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WO2022206461A1 - 供电系统及直流汇流箱的输出电压控制方法 - Google Patents

供电系统及直流汇流箱的输出电压控制方法 Download PDF

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Publication number
WO2022206461A1
WO2022206461A1 PCT/CN2022/082084 CN2022082084W WO2022206461A1 WO 2022206461 A1 WO2022206461 A1 WO 2022206461A1 CN 2022082084 W CN2022082084 W CN 2022082084W WO 2022206461 A1 WO2022206461 A1 WO 2022206461A1
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WO
WIPO (PCT)
Prior art keywords
output
voltage
combiner box
combiner
preset
Prior art date
Application number
PCT/CN2022/082084
Other languages
English (en)
French (fr)
Inventor
陈东
高拥兵
石磊
Original Assignee
华为数字能源技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 华为数字能源技术有限公司 filed Critical 华为数字能源技术有限公司
Priority to EP22778644.9A priority Critical patent/EP4311063A4/en
Publication of WO2022206461A1 publication Critical patent/WO2022206461A1/zh
Priority to US18/474,453 priority patent/US20240014664A1/en

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
    • H02M1/007—Plural converter units in cascade
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
    • H02M1/0077—Plural converter units whose outputs are connected in series
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/36—Means for starting or stopping converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/493—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode the static converters being arranged for operation in parallel
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/22—The renewable source being solar energy
    • H02J2300/24—The renewable source being solar energy of photovoltaic origin

Definitions

  • the present application relates to the technical field of electronic circuits, and in particular, to a power supply system and an output voltage control method of a DC combiner box.
  • the power supply system includes multiple DC power sources, multiple DC combiner boxes and inverters, wherein the input end of each DC combiner box is connected to at least one DC power source, and the output end is connected to the inverter , each DC combiner box is used to convert the DC power of at least one DC power supply connected to its input end to DC and output it to the inverter.
  • the inverter in the output voltage control mode of the DC combiner box, the inverter sends a communication signal to the DC combiner box, and the DC combiner box controls its own output voltage according to the received communication signal, thereby realizing the startup of the DC combiner box. , and supply power to the inverter.
  • the above method has the following problems: when the communication between the DC combiner box and the inverter is difficult (for example, the communication link is abnormal such as the communication signal is absorbed or blocked, or the inverter cannot send the communication signal without obtaining power), It will cause the DC combiner box to fail to start and work normally, resulting in poor stability of the power supply system.
  • the present application provides a power supply system and a method for controlling the output voltage of a DC combiner box.
  • the DC combiner box can determine the connection relationship between itself and other DC combiner boxes or inverters according to its own output terminal parameters, and then can control according to the connection relationship. Its own output voltage ensures that the DC combiner box can still start and work normally when it is difficult to communicate with the inverter, which improves the stability of the power supply system and has strong applicability.
  • the present application provides a power supply system
  • the power supply system includes at least one DC combiner box and an inverter, and the output ends of each DC combiner box in the at least one DC combiner box are connected in series and/or parallel to the inverter.
  • the input ends of the DC combiner boxes are coupled to the DC power supply, and the DC combiner boxes include a controller, a detection circuit and a DC conversion circuit.
  • the output end of the circuit is coupled with the output end of the DC combiner box, and the DC conversion circuit is used to DC convert the input terminal voltage of the DC combiner box to the output terminal voltage of the DC combiner box.
  • the detection circuit detects the output terminal parameters of the DC combiner box, and sends the output terminal parameters of the DC combiner box to the controller, and the controller controls the output voltage of the DC conversion circuit according to the output terminal parameters of the DC combiner box. Furthermore, the DC combiner box can determine the connection relationship between the DC combiner box and other DC combiner boxes or inverters according to the parameters of the output terminal, and control the output voltage of the DC conversion circuit according to the connection relationship to ensure that the DC combiner box is connected to the inverter.
  • the device can still start and work normally even when the communication is difficult, which improves the stability of the power supply system and has strong applicability.
  • the controller determines the output impedance value of the DC combiner box according to the first preset voltage and the output current of the DC combiner box, and the output impedance value of the DC combiner box is greater than the preset value.
  • the output impedance threshold it is determined that the DC combiner box is connected to the inverter, and then the output voltage of the DC conversion circuit is controlled to be adjusted from the first preset voltage to the second preset voltage.
  • the first preset voltage is a DC voltage, an AC current, or a DC voltage superimposed on an AC voltage. Furthermore, when the first preset voltage is a DC voltage, the DC combiner box can calculate and obtain the resistance value of the resistive part of the output impedance value of the DC combiner box; when the first preset voltage is an AC voltage, calculate and obtain The impedance value of the capacitive part and the impedance value of the inductive part in the output impedance value of the DC combiner box; in the case where the first preset voltage is a DC voltage superimposed on an AC voltage, the impedance value of the resistive part in the output impedance value of the DC combiner box is calculated and obtained , capacitive part impedance value and inductive part impedance value.
  • the DC combiner box may determine the output impedance value of the DC combiner box according to the first preset current and the output terminal voltage of the DC combiner box, and determine the output impedance value of the DC combiner box at the output impedance of the DC combiner box. When the value is greater than the preset output impedance threshold, it is determined that the DC combiner box is connected to the inverter, and then the output voltage of the DC conversion circuit is controlled to be the second preset voltage.
  • the first preset current is a direct current, an alternating current, or a direct current superimposed on an alternating current.
  • the DC combiner box can calculate the resistance value of the resistive part of the output impedance value of the DC combiner box when the first preset current is a DC current; and when the first preset current is an AC current, calculate and obtain The impedance value of the capacitive part and the impedance value of the inductive part in the output impedance value of the DC combiner box; in the case where the first preset current is the DC current superimposed on the AC current, the impedance value of the resistive part in the output impedance value of the DC combiner box is calculated and obtained , capacitive part impedance value and inductive part impedance value.
  • a fifth possible implementation manner when the output terminal voltage of the DC combiner box meets the preset output voltage range or the output terminal current meets the preset output current range, according to the output terminal voltage of the DC combiner box and the output current to determine the output impedance value of the DC combiner box, and when the output impedance value of the DC combiner box is greater than the preset output impedance threshold, it is determined that the DC combiner box is connected to the inverter, and then the DC converter in the DC combiner box is controlled. The output voltage of the circuit is adjusted to the second preset voltage.
  • the output terminal voltage of the DC combiner box includes DC voltage and/or AC voltage
  • the output terminal current includes DC current and/or AC current.
  • the DC combiner box can calculate the impedance value of the resistive part of the output impedance value of the DC combiner box when the output voltage and output current are both DC; when the output voltage and output current are both AC , the capacitive part impedance value and the inductive part impedance value of the output impedance value of the DC combiner box are calculated; when the output voltage and output current are both DC and AC, the output impedance value of the DC combiner box is calculated.
  • the impedance value of the capacitive part, the impedance value of the capacitive part and the impedance value of the inductive part are calculated.
  • the DC combiner box may determine that the DC combiner box is connected to the inverter when the output residual current of the DC combiner box is greater than a preset residual current threshold, and control the The output voltage of the DC conversion circuit is the second preset voltage.
  • the DC combiner box further includes a communication circuit, where the communication circuit is configured to receive an instruction sent by the inverter, and send the instruction to the controller.
  • the controller controls the output voltage of the DC conversion circuit to be a third preset voltage, where the third preset voltage is greater than or equal to the second preset voltage, and the third preset voltage is the DC conversion The rated voltage of the circuit.
  • the DC combiner box does not change the output voltage of the DC conversion circuit until after receiving the instruction sent by the inverter, and controls the output of the DC conversion circuit
  • the voltage is adjusted from the second preset voltage to the rated voltage, so that the DC combiner box completes the startup.
  • the DC combiner box no longer controls the output voltage of the DC conversion circuit to continue to increase, but only continues to control when an instruction sent by the inverter is received.
  • the DC conversion circuit completes the startup, which can effectively reduce the loss of the power supply system and reduce the probability of misoperation of the power supply system.
  • the DC conversion circuit includes a power conversion circuit, a voltage regulation circuit, and a disconnect switch, and the output voltage of the power conversion circuit is greater than the output voltage of the voltage regulation circuit, wherein the power conversion circuit The input end is coupled with the input end of the DC conversion circuit through the disconnect switch, the output end of the power conversion circuit is coupled with the output end of the DC conversion circuit; the input end of the voltage regulation circuit is coupled with the input end of the DC conversion circuit, and the output end of the voltage regulation circuit It is coupled with the output terminal of the DC conversion circuit.
  • the DC combiner box can be disconnected by controlling the disconnect switch, and the output voltage of the control voltage regulating circuit is the first preset voltage, so that the output voltage of the DC combiner box is the first preset voltage. Furthermore, in the case where the power conversion circuit does not have the step-down function, the DC conversion circuit can still realize the output value of a low voltage of the first preset voltage.
  • the DC combiner box may determine that the DC combiner box is connected to other DC combiner boxes when the output terminal voltage is greater than the preset output voltage threshold, and the DC combiner box is connected to the DC combiner box.
  • the other DC combiner boxes connected to the combiner box have started to start.
  • the DC combiner box controls the output voltage of the DC conversion circuit to follow the output voltage of the DC combiner box to output, thereby avoiding the current DC combiner box.
  • the DC combiner box may determine that the DC combiner box is connected to other DC combiner boxes when the output current is greater than the preset output current threshold, and the DC combiner box is connected to the DC combiner box.
  • the other DC combiner boxes connected to the DC combiner box have started to start.
  • the output voltage of the DC combiner box controls the output voltage of the DC converter circuit to follow the output voltage of the DC combiner box to output, thereby avoiding the output voltage when the current DC combiner box is not started.
  • the current impact problem caused by too high has been solved, and it is guaranteed that the current DC combiner box can still start and work normally when it is difficult to communicate with the inverter and other connected DC return boxes.
  • the inverter includes a first inverter and a second inverter
  • at least one DC combiner box includes a first group of DC combiner boxes and a second group of DC combiner boxes
  • the first group of DC combiner boxes and the second group of DC combiner boxes each include at least one DC combiner box, wherein: the output ends of each DC combiner box in the first group of DC combiner boxes are connected in parallel, and each DC combiner box in the second group of DC combiner boxes is connected in parallel.
  • the output ends of the combiner boxes are connected in parallel; the first output ends of each DC combiner box in the first group of DC combiner boxes are coupled to form a first node; the first node is connected with the first input end of the first inverter through a first wire; The second output end of each DC combiner box in the first group of DC combiner boxes is coupled with the first output end of each DC combiner box in the second group of DC combiner boxes to form a second node; each DC combiner in the second group of DC combiner boxes The second output end of the box is coupled to form a third node; the third node is connected with the second input end of the second inverter through a second wire; the second input end of the first inverter is connected with the second input end of the second inverter The first input terminal is coupled to form a fourth node; the fourth node and the second node are connected by a third wire, wherein the current capacity of the first wire and the current capacity of the second wire are both greater than or equal to the third wire.
  • the above-mentioned method for controlling the output voltage of the DC combiner box is also applicable to the power supply system provided in the embodiment of the present application. Since the output current of the first group of DC combiner boxes and the output current of the second group of DC combiner boxes simultaneously flow through the third wire, And in the opposite direction, there is a phenomenon of cancellation. Therefore, in the normal working mode, the current value of the third wire is less than or equal to the current value of the first wire or the second wire, and the wire with lower current capacity can be selected to save the wire. cable, reducing the cost of the power supply system.
  • the output voltage of the first group of DC combiner boxes in the maintenance mode is different from the output voltage of the second group of DC combiner boxes in the maintenance mode, and the first group of DC combiner boxes has a different output voltage in the maintenance mode.
  • Each DC combiner box in the DC combiner box has the same output voltage in the maintenance mode
  • each DC combiner box in the second group of DC combiner boxes has the same output voltage in the maintenance mode.
  • the DC power source is a photovoltaic string
  • the application scene of the power supply system is a photovoltaic scene.
  • the present application provides an output voltage control method for a DC combiner box, and the method is suitable for a power supply system, where the power supply system includes at least one DC combiner box and an inverter, and each DC combiner box in the at least one DC combiner box The output terminals of the inverter are connected in series and/or parallel to the input terminal of the inverter, and the input terminals of each DC combiner box are connected to the DC power supply.
  • the DC combiner box includes a controller, a detection circuit and a DC conversion circuit, wherein the DC conversion circuit
  • the input terminal is coupled with the input terminal of the DC combiner box
  • the output terminal of the DC converter circuit is coupled with the output terminal of the DC combiner box
  • the DC converter circuit converts the input terminal voltage of the DC combiner box to the output terminal voltage of the DC combiner box.
  • the detection circuit detects the output terminal parameters of the DC combiner box, and sends the output terminal parameters of the DC combiner box to the controller, and the controller controls the output voltage of the DC conversion circuit according to the output terminal parameters of the DC combiner box.
  • the controller determines the output impedance value of the DC combiner box according to the first preset voltage and the output current of the DC combiner box, and the output impedance value of the DC combiner box is greater than the preset value.
  • the output impedance threshold it is determined that the DC combiner box is connected to the inverter, and then the output voltage of the DC conversion circuit is controlled to be adjusted from the first preset voltage to the second preset voltage.
  • the first preset voltage is a DC voltage, an AC voltage, or a DC voltage superimposed on an AC voltage.
  • the DC combiner box may determine the output impedance value of the DC combiner box according to the first preset current and the output terminal voltage of the DC combiner box, and determine the output impedance value of the DC combiner box at the output impedance of the DC combiner box. When the value is greater than the preset output impedance threshold, it is determined that the DC combiner box is connected to the inverter, and then the output voltage of the DC conversion circuit is controlled to be the second preset voltage.
  • the first preset current is a direct current, an alternating current, or a direct current superimposed on an alternating current.
  • the output terminal voltage of the DC combiner box includes DC voltage and/or AC voltage
  • the output terminal current includes DC current and/or AC current
  • the DC combiner box may determine that the DC combiner box is connected to the inverter when the output residual current is greater than the preset residual current threshold, and control the DC conversion circuit.
  • the output voltage is the second preset voltage.
  • the DC combiner box further includes a communication circuit, where the communication circuit is configured to receive an instruction sent by the inverter, and send the instruction to the controller.
  • the controller controls the output voltage of the DC conversion circuit to be a third preset voltage, where the third preset voltage is greater than or equal to the second preset voltage, and the third preset voltage is the DC conversion The rated voltage of the circuit.
  • the DC conversion circuit includes a power conversion circuit, a voltage regulation circuit, and a disconnect switch, and the output voltage of the power conversion circuit is greater than the output voltage of the voltage regulation circuit, wherein the power conversion circuit
  • the input end is coupled with the input end of the DC conversion circuit through the disconnect switch, the output end of the power conversion circuit is coupled with the output end of the DC conversion circuit; the input end of the voltage regulation circuit is coupled with the input end of the DC conversion circuit, and the output end of the voltage regulation circuit It is coupled with the output terminal of the DC conversion circuit.
  • the DC combiner box can be disconnected by controlling the disconnect switch, and the output voltage of the control voltage regulating circuit is the first preset voltage, so that the output voltage of the DC combiner box is the first preset voltage.
  • the DC combiner box controls the output voltage of the DC conversion circuit to follow the output voltage of the DC combiner box to output.
  • the DC combiner box when the output current of the DC combiner box is greater than the preset output current threshold, it is determined that the DC combiner box is connected to other DC combiner boxes, and the DC combiner box is connected to the DC combiner box.
  • the other DC combiner boxes connected to the combiner box have started to start.
  • the DC combiner box controls the output voltage of the DC conversion circuit to follow the output voltage of the DC combiner box to output.
  • the inverter includes a first inverter and a second inverter, and at least one DC combiner box includes a first group of DC combiner boxes and a second group of DC combiner boxes
  • the first group of DC combiner boxes and the second group of DC combiner boxes each include at least one DC combiner box, wherein: the output ends of each DC combiner box in the first group of DC combiner boxes are connected in parallel, and each DC combiner box in the second group of DC combiner boxes is connected in parallel.
  • the output ends of the combiner boxes are connected in parallel; the first output ends of each DC combiner box in the first group of DC combiner boxes are coupled to form a first node; the first node is connected with the first input end of the first inverter through a first wire; The second output end of each DC combiner box in the first group of DC combiner boxes is coupled with the first output end of each DC combiner box in the second group of DC combiner boxes to form a second node; each DC combiner in the second group of DC combiner boxes The second output end of the box is coupled to form a third node; the third node is connected with the second input end of the second inverter through a second wire; the second input end of the first inverter is connected with the second input end of the second inverter The first input terminal is coupled to form a fourth node; the fourth node and the second node are connected through a third wire, wherein the current capacity of the first wire and the current capacity of the second wire are both greater than or equal to the current capacity of the third wire. flow
  • the output voltage of the first group of DC combiner boxes in the maintenance mode is different from the output voltage of the second group of DC combiner boxes in the maintenance mode, and the first group of DC combiner boxes is different.
  • Each DC combiner box in the DC combiner box has the same output voltage in the maintenance mode, and each DC combiner box in the second group of DC combiner boxes has the same output voltage in the maintenance mode.
  • the DC power source is a photovoltaic string. It should be understood that the implementation and beneficial effects of the above-mentioned aspects of the present application may refer to each other.
  • Fig. 1a is an output voltage control method of a DC combiner box provided by the prior art
  • FIG. 1b is a schematic structural diagram of a power supply system in which the output ends of the DC combiner box provided in the present application are connected in parallel;
  • 2a is a schematic structural diagram of a DC conversion circuit provided by the present application.
  • FIG. 2b is another schematic structural diagram of the DC conversion circuit provided by the present application.
  • FIG. 3 is another schematic structural diagram of a power supply system in which the output ends of the DC combiner box provided in the present application are connected in parallel;
  • FIG. 4 is another structural schematic diagram of the power supply system in which the output ends of the DC combiner box provided in the present application are connected in parallel;
  • FIG. 5 is a schematic structural diagram of a power supply system in which the output ends of the DC combiner box provided by the present application are connected in series;
  • FIG. 6 is another structural schematic diagram of the power supply system in which the output ends of the DC combiner boxes provided by the present application are connected in series;
  • FIG. 7 is a schematic structural diagram of a power supply system in which the output ends of the DC combiner box are combined in series and parallel provided by the present application.
  • the power supply system and the output voltage control method of the DC combiner box provided by this application can be applied to the following scenarios:
  • the technical solution of the present application can be applied to a photovoltaic scenario, and the DC power supply in the power supply system provided by the present application is a photovoltaic string, and each photovoltaic string may include a plurality of series and/or parallel photovoltaic modules.
  • the power supply system also includes at least one DC combiner box and an inverter, the output end of the at least one DC combiner box is connected in series and/or in parallel with the input end of the inverter, and the input end of each DC combiner box is connected to at least one photovoltaic group. It is used to boost the DC power generated by the PV string connected to it and output it to the inverter.
  • the inverter is used to convert the boosted DC power generated by the DC combiner box into a DC power that meets the requirements of the grid. alternating current.
  • the power supply system can transmit the inverted alternating current to the grid.
  • the power supply system can also be applied to the uninterruptible power supply scenario, that is, the power supply system can be provided with energy storage batteries, such as nickel-cadmium batteries, nickel-hydrogen batteries, lithium-ion batteries, and lithium-polymer batteries Wait.
  • the DC combiner box includes a detection circuit, a DC conversion circuit and a controller.
  • the detection circuit detects the output terminal parameters of the DC combiner box, and sends the output terminal parameters of the DC combiner box to the controller.
  • the controller determines the DC combiner box and other DC combiner boxes in the power supply system according to the output terminal parameters of the DC combiner box or the power supply system.
  • the connection relationship of the inverter, and then the output voltage of the DC conversion circuit can be controlled according to the connection relationship, so as to ensure that the DC combiner box can still start and work normally when it is difficult to communicate with the inverter, which improves the stability of the power supply system. Strong applicability.
  • the technical solution of the present application can also be applied to a photovoltaic scenario where multiple machines are connected in parallel, and the DC power supply in the power supply system provided by the present application can be either a photovoltaic string or an energy storage battery pack.
  • Each energy storage battery string may include a plurality of energy storage batteries connected in series and/or in parallel.
  • the power supply system also includes at least one DC combiner box and an inverter, the output end of the at least one DC combiner box is coupled in series and/or in parallel with the input end of the inverter, and the input end of the DC combiner box can be connected to at least one photovoltaic string It is used to boost the DC power generated by the photovoltaic string connected to it and output it to the inverter; the input end of the DC combiner box can also be connected to at least one energy storage battery string to connect the energy storage battery connected to it. The DC power generated by the battery string is converted to DC and then output to the inverter.
  • the power supply system includes a first DC combiner box and a second DC combiner box, wherein the first DC combiner box is connected to at least one photovoltaic string, and the second DC combiner box is connected to at least one energy storage battery string. connected.
  • the inverter is used to convert the DC power generated by the DC combiner box after boosting or DC conversion into AC power that meets the requirements of the power grid.
  • the power supply system can transmit the inverted alternating current to the grid.
  • the power supply system can also be applied to the uninterruptible power supply scenario, that is, the power supply system can be provided with energy storage batteries, such as nickel-cadmium batteries, nickel-hydrogen batteries, lithium-ion batteries, and lithium-polymer batteries Wait.
  • the DC combiner box includes a detection circuit, a DC conversion circuit and a controller.
  • the detection circuit detects the output terminal parameters of the DC combiner box, and sends the output terminal parameters of the DC combiner box to the controller.
  • the controller determines the DC combiner box and other DC combiner boxes in the power supply system according to the output terminal parameters of the DC combiner box or the power supply system.
  • the connection relationship of the inverter, and then the output voltage of the DC conversion circuit can be controlled according to the connection relationship, so as to ensure that the DC combiner box can still start and work normally when it is difficult to communicate with the inverter, which improves the stability of the power supply system. Strong applicability.
  • the technical solution of the present application can also be applied to battery charging/discharging scenarios, then the DC power supply in the power supply system provided by the present application is an energy storage battery string, and each energy storage battery string can be Including a plurality of energy storage batteries connected in series and/or in parallel.
  • the power supply system also includes at least one DC combiner box and an inverter, the output end of the at least one DC combiner box is connected in series and/or in parallel with the input end of the inverter, and the input end of the DC combiner box is connected with at least one energy storage battery pack It is used to convert the direct current generated by the energy storage battery string connected to it and output it to the inverter after direct current conversion.
  • the inverter is used to convert the DC power generated by the DC combiner box after DC conversion into AC power that meets the requirements of the power grid.
  • the power supply system can transmit the inverted AC power to the grid.
  • the DC combiner box includes a detection circuit, a DC conversion circuit and a controller.
  • the detection circuit detects the output terminal parameters of the DC combiner box, and sends the output terminal parameters of the DC combiner box to the controller.
  • the controller determines the DC combiner box and other DC combiner boxes in the power supply system according to the output terminal parameters of the DC combiner box or the power supply system.
  • the connection relationship of the inverter, and then the output voltage of the DC conversion circuit can be controlled according to the connection relationship, so as to ensure that the DC combiner box can still start and work normally when it is difficult to communicate with the inverter, which improves the stability of the power supply system. Strong applicability.
  • FIG. 1b is a schematic structural diagram of a power supply system provided by the present application in which the output ends of the DC combiner box are connected in parallel.
  • the power supply system 1 includes a DC combiner box 10, a DC combiner box 11, . ..., the DC power supply 100a is connected, the input end of the DC combiner box 11 is connected with the DC power supply 1101, the DC power supply 1102, ..., the DC power supply 110b, ..., the input end of the DC combiner box 1n is connected with the DC power supply 1n01, the DC power supply 1n02, ...,
  • the DC power source 1n0x is connected to the DC combiner box 10, the DC combiner box 11, . . . and the output ends of the DC combiner box 1n are connected in parallel with the input end of the inverter 20 through connecting wires, and the output end of the inverter 20 is connected to the AC power grid .
  • the DC combiner box 10 includes a DC conversion circuit 101 , a detection circuit 102 and a controller 103 , wherein the input terminal of the DC conversion circuit 101 is coupled with the input terminal of the DC combiner box 10 , and the output terminal of the DC conversion circuit 101 passes through the detection circuit 102 and the DC link.
  • the output of the combiner box 10 is coupled.
  • the controller 103 can determine the connection relationship between the DC combiner box 10 and other DC combiner boxes in the power supply system 1 (corresponding to the DC combiner boxes 11 , . , and control the output voltage of the DC conversion circuit 101 according to the connection relationship.
  • the controller 103 when the input terminal of the DC combiner box 10 supplies power, the controller 103 starts to work, and simultaneously controls the output voltage of the DC conversion circuit 101 to be a first preset voltage, wherein the first preset voltage includes a DC voltage , AC voltage or DC voltage superimposed AC voltage.
  • the first preset voltage may be less than or equal to the safety voltage of the human body, such as 36V.
  • FIG. 2a is a schematic structural diagram of the DC conversion circuit provided by the present application.
  • the DC conversion circuit 101 includes a main power circuit 1011 (such as a Buck-Boost conversion circuit), and a controllable switch tube in the main power circuit 1011 is connected to a controller.
  • a main power circuit 1011 such as a Buck-Boost conversion circuit
  • a controllable switch tube in the main power circuit 1011 is connected to a controller.
  • the controller 103 can output a corresponding pulse width modulated wave with a fixed duty cycle to the controllable switch tube in the main power circuit 1011, so that the output of the DC conversion circuit 101 The voltage is the first preset voltage.
  • the controller 103 can output a corresponding pulse width modulated wave with a continuously changing duty cycle to the controllable switch tube in the main power circuit 1011, and control the The changing frequency is lower than the switching frequency of the controllable switch tube, so that the output voltage of the DC conversion circuit 101 is the first preset voltage.
  • the controller 103 can output a pulse width modulated wave with a corresponding duty cycle that is constantly changing around a fixed value to the controllable switch tube in the main power circuit 1011,
  • the change frequency of the control duty ratio is lower than the switching frequency of the controllable switch tube, so that the output voltage of the DC conversion circuit 101 is the first preset voltage.
  • Fig. 2b is another schematic structural diagram of the DC conversion circuit provided by the present application.
  • the DC conversion circuit 101 includes a disconnect switch 1012, a power conversion circuit 1013 and a voltage regulation circuit 1013, wherein the power conversion circuit 1013 does not have a step-down function, and the output voltage of the power conversion circuit 1013 is greater than that of the voltage regulation circuit 1014 output voltage.
  • the input end of the power conversion circuit 1013 is coupled with the input end of the DC conversion circuit 101 through the disconnect switch 1012, and the output end is coupled with the output end of the DC conversion circuit 101; the input end of the voltage regulation circuit 1014 is coupled with the input end of the DC conversion circuit 101, The output terminal is coupled to the output terminal of the DC conversion circuit 101 . Since the power conversion circuit 1013 (such as the Boost conversion circuit) itself cannot output a lower voltage, and when the input voltage of the DC conversion circuit 101 is relatively high, the output voltage of the power conversion circuit 1013 may also follow the input voltage of the DC conversion circuit 101 .
  • the controller 103 controls the disconnecting switch 1012 to be turned off, so that the power conversion circuit 1013 does not work, and at the same time, controls the output voltage of the voltage regulating circuit 1014 to be the first preset voltage, so that the output voltage of the DC conversion circuit 101 is the first preset voltage.
  • the voltage regulation circuit 1014 may be an additional circuit, or may be shared with the precharge circuit, the soft start circuit, the potential induced decay circuit, etc. in the DC conversion circuit 101 .
  • the controller 103 controls the first preset voltage output by the DC conversion circuit 101 to be a DC voltage, an AC voltage, or a DC voltage superimposed on an AC voltage.
  • the specific implementation can refer to the controller 103 in the embodiment shown in FIG. 2a to control the DC conversion circuit 101.
  • the outputted first preset voltage is a specific implementation manner of a DC voltage, an AC voltage, or a DC voltage superimposed on an AC voltage, which will not be repeated here.
  • the controller 103 sends an output current sampling signal to the detection circuit 102 when the output voltage of the DC conversion circuit 101 is the first preset voltage.
  • the detection circuit 102 collects the output terminal current of the DC combiner box 10 according to the output current sampling signal, and returns the output terminal current of the DC combiner box 10 to the controller 103 .
  • the controller 103 determines the ratio between the first preset voltage and the output current of the DC combiner box 10 as the output impedance value of the DC combiner box 10, and compares the output impedance value of the DC combiner box 10 with the preset output impedance threshold.
  • the controller 103 controls the output voltage of the DC conversion circuit 101 to be the second preset voltage, reference may be made to the specific implementation of the controller 103 controlling the output voltage of the DC conversion circuit 101 to be the first preset voltage in the embodiment of the present application method, which will not be repeated here.
  • the controller 103 when the input terminal of the DC combiner box 10 supplies power, the controller 103 starts to work, and at the same time controls the output current of the DC conversion circuit 101 to be a first preset current, wherein the first preset current includes DC Current, alternating current or direct current superimposed alternating current.
  • the first preset current may be less than or equal to the safety current of the human body, or, when the output current of the DC conversion circuit 101 is the first preset current, the input voltage of the DC conversion circuit 101 may be less than or equal to the safety voltage of the human body.
  • the controller 103 controls the output current of the DC conversion circuit 101 to be the first preset current
  • the controller 103 sends an output voltage sampling signal to the detection circuit 102 when the output current of the DC conversion circuit 101 is the first preset current.
  • the detection circuit 102 collects the output terminal voltage of the DC combiner box 10 according to the output voltage sampling signal, and returns the output terminal voltage of the DC combiner box 10 to the controller 103 .
  • the controller 103 determines the ratio between the output terminal voltage of the DC combiner box 10 and the first preset current as the output impedance value of the DC combiner box 10, and compares the output impedance value of the DC combiner box 10 with the preset output impedance threshold value.
  • the controller 103 controls the output voltage of the DC conversion circuit 101 to be the second preset voltage.
  • the controller 103 can further determine the connection relationship between the DC combiner box 10 and the DC combiner boxes 11, . . . , and the DC combiner box 1n by changing the preset output impedance threshold.
  • the controller 103 in order to enable the inverter 20 to obtain sufficient power and start normally, the controller 103 usually determines the number of the DC combiner box 10 connected to the inverter 20 and other DC combiner boxes connected to the DC combiner box 10 In the case of being larger than the preset number threshold, the output voltage of the DC conversion circuit 101 is controlled to be the second preset voltage.
  • the controller 103 can control the DC conversion circuit 101 to output the first preset voltage of the DC voltage superimposed on the AC voltage, and the detection circuit 102 detects that the output voltage of the DC conversion circuit 101 is DC when the output voltage is the first preset voltage.
  • the current at the output end of the combiner box 10 can effectively detect the magnitude of the resistive impedance, capacitive impedance and inductive impedance of the output end of the DC combiner box 10 .
  • the controller 103 can also control the DC conversion circuit 101 to output the first preset current of the DC current superimposed on the AC current, and detect the DC combiner box when the output current of the DC conversion circuit 101 is the first preset current through the detection circuit 102.
  • the output terminal voltage of 10 can effectively detect the resistive impedance, capacitive impedance and inductive impedance of the output terminal of the DC combiner box 10.
  • the controller 103 can determine whether the output end of the DC combiner box 10 is not based on the calculated output impedance value of the DC combiner box 10 .
  • the connection relationship between each DC combiner box and each inverter 20 in the power supply system 1 where the DC combiner box 10 is located can also be determined.
  • each DC combiner box is resistive parallel capacitive, and the resistance value is 1M ⁇ , the capacitance value is 100 ⁇ F; the input impedance of the inverter is inductive series capacitive, and the inductance value is 100 ⁇ H , the capacitance value is 500 ⁇ F.
  • the output impedance of the DC combiner box calculated by the controller is a 0.2M ⁇ resistor in parallel with a 500 ⁇ F capacitor, and then a 100 ⁇ H inductor and a 500 ⁇ F capacitor in series, the controller can determine that the output end of the DC combiner box is connected to 4 other DC combiner boxes , and an inverter is connected; at the same time, the DC combiner boxes are in a parallel relationship, and the output terminals of each DC combiner box are connected in parallel and then connected in parallel with the input terminal of the inverter.
  • the controller 103 may determine the connection relationship between the DC combiner box 10 and the DC combiner box 11 , . . . , the DC combiner box 1n and the inverter 20 according to the calculated output impedance value of the DC combiner box 10 , and The output voltage of the DC conversion circuit 101 is controlled according to the connection relationship to ensure that the DC combiner box 10 can still start and work normally even when it is difficult to communicate with the inverter 20 , which improves the stability of the power supply system 1 and has strong applicability.
  • the present application also provides an output voltage control method for a DC combiner box, including:
  • the controller 103 controls the output voltage of the DC conversion circuit 101 to be the first preset voltage, and determines the output impedance value of the DC combiner box 10 according to the first preset voltage and the output current of the DC combiner box 10 .
  • the output voltage of the DC conversion circuit 101 is controlled to be the second preset voltage, wherein the output current of the DC combiner box 10 is determined by the detection circuit 102 at the output voltage of the DC conversion circuit 101 It is detected under the condition of the first preset voltage.
  • the controller 103 controls the output current of the DC conversion circuit 101 to be the first preset current, and determines the output impedance value of the DC combiner box 10 according to the first preset current and the output terminal voltage of the DC combiner box 10 .
  • the output impedance value of 10 is greater than the preset output impedance threshold
  • the output voltage of the DC conversion circuit 101 is controlled to be the second preset voltage, wherein the output terminal voltage of the DC combiner box 10 is determined by the detection circuit 102 in the DC conversion circuit 101. It is detected when the output current is the first preset current.
  • the controller 103 starts to work, and sends the output voltage and current to the detection circuit 102 at the same time sampled signal.
  • the detection circuit 102 collects the output terminal voltage and output terminal current of the DC combiner box 10 according to the output voltage and current sampling signal, and returns the output terminal voltage and output terminal current of the DC combiner box 10 to the controller 103 .
  • the controller 103 determines whether the output terminal voltage of the DC combiner box 10 satisfies the preset output voltage range (that is, greater than 0 and less than or equal to the first preset voltage), and the output terminal voltage of the DC combiner box 10 satisfies the preset output voltage In the case of the voltage range, it means that the DC combiner box 10 is connected to other DC combiner boxes in the power supply system 1, and that other DC combiner boxes connected to the DC combiner box 10 have already started to output the first preset voltage, and the DC combiner box 10 does not need to be any longer.
  • the preset output voltage range that is, greater than 0 and less than or equal to the first preset voltage
  • the controller 103 determines the ratio between the output terminal voltage of the DC combiner box 10 and the output terminal current as the output impedance value of the DC combiner box 10, and determines the output impedance value of the DC combiner box 10 as the output impedance value of the DC combiner box 10.
  • the output impedance is greater than the preset output impedance threshold, the output voltage of the DC conversion circuit 101 is controlled to be adjusted to the second preset voltage.
  • the controller 103 determines whether the output current of the DC combiner box 10 satisfies the preset output current range (that is, greater than 0 and less than or equal to the first preset current), and the output current of the DC combiner box 10 meets the preset output current range.
  • the controller 103 determines the ratio between the output terminal voltage of the DC combiner box 10 and the output terminal current as the output impedance value of the DC combiner box 10, and determines the output impedance of the DC combiner box 10 as the output impedance value of the DC combiner box 10.
  • the output voltage of the DC conversion circuit 101 is controlled to be adjusted to the second preset voltage.
  • the controller 103 does not need to output the first preset voltage when the output voltage of the DC combiner box 10 meets the preset output voltage range, or the current at the output terminal of the DC combiner box 10 meets the preset output voltage range. In the case of the preset output current range, there is no need to output the first preset current.
  • the output voltage of the circuit 101 further responds to the situation that other existing DC combiner boxes start to output voltage or current, and avoids that the DC combiner box 10 outputs voltage or current again and conflicts with the output voltage or current of other existing DC combiner boxes. problems, and ensure that the DC combiner box 10 can still start and work normally when it is difficult to communicate with the inverter 20 and other connected DC combiner boxes, which improves the stability of the power supply system 1 and has strong applicability.
  • the present application also provides an output voltage control method for a DC combiner box, including:
  • the DC combiner is determined according to the output terminal voltage and output terminal current of the DC combiner box 10
  • the output impedance value of the box 10 when the output impedance value of the DC combiner box 10 is greater than the preset output impedance threshold, the output voltage of the DC conversion circuit 101 is controlled to be the second preset voltage, wherein the output terminal of the DC combiner box 10
  • the voltage and the output terminal current are detected by the detection circuit 102 under the condition that the input parameters of the DC combiner box 10 are not the preset input parameter values.
  • the controller 103 starts to work, and sends the output residual current to the detection circuit 102 at the same time. sampled signal.
  • the detection circuit 102 collects the output residual current of the DC combiner box 10 according to the output residual current sampling signal, and returns the output residual current of the DC combiner box 10 to the controller 103 .
  • the controller 103 compares the output residual current of the DC combiner box 10 with the preset residual current threshold, and in the case where the output residual current of the DC combiner box 10 is greater than the preset residual current threshold (eg 100mA), determines The inverter 20 is connected, and controls the output voltage of the DC conversion circuit 101 to be the second preset voltage.
  • the detection circuit 102 is a residual current device (Residual Current Device, RCD).
  • the controller 103 may determine the connection relationship between the DC combiner box 10 and the inverter 20 according to the output residual current of the DC combiner box 10, and control the output voltage of the DC conversion circuit 101 according to the connection relationship to ensure the DC
  • the combiner box 10 can still start and work normally even when it is difficult to communicate with the inverter 20 , which improves the stability of the power supply system 1 and has strong applicability.
  • the present application also provides an output voltage control method for a DC combiner box, including:
  • the controller 103 controls the output voltage of the DC conversion circuit 101 to be the second preset voltage, wherein the output residual current of the DC combiner box 10 is determined by the detection circuit. 102 is detected when the input parameter of the DC combiner box 10 is not the preset input parameter value.
  • the controller 103 starts to work, and sends the output voltage sample to the detection circuit 102 at the same time Signal.
  • the detection circuit 102 collects the output terminal voltage of the DC combiner box 10 according to the output voltage sampling signal, and returns the output terminal voltage of the DC combiner box 10 to the controller 103 .
  • the controller 103 determines whether the output terminal voltage of the DC combiner box 10 is greater than a preset output voltage threshold, wherein the preset output voltage threshold is greater than a first preset voltage. In the case that the output terminal voltage of the DC combiner box 10 is greater than the preset output voltage threshold, it means that the DC combiner box 10 is connected to other DC combiner boxes in the power supply system 1, and other DC combiner boxes connected to the DC combiner box 10 have started After startup, the controller 103 controls the output voltage of the DC conversion circuit 101 to adjust to the output terminal voltage of the DC combiner box 10 , that is, controls the output voltage of the DC conversion circuit 101 to follow the output terminal voltage of the DC combiner box 10 .
  • the controller 103 can determine that other DC combiner boxes connected to the DC combiner box 10 have started to start when the output voltage of the DC combiner box 10 is greater than the preset output voltage threshold, and then controls the DC conversion
  • the output voltage of the circuit 101 follows the output terminal voltage of the DC combiner box 10 , thereby avoiding the current impact problem caused by the high output terminal voltage when the DC combiner box 10 is not started, and ensuring that the DC combiner box 10 is connected with the inverter 20 .
  • other connected DC combiner boxes can still start and work normally even when it is difficult to communicate, which improves the stability of the power supply system 1 and has strong applicability.
  • the present application also provides an output voltage control method for a DC combiner box, including:
  • the output terminal parameters of the DC combiner box 10 include the output terminal voltage of the DC combiner box 10;
  • the controller 103 controls the output voltage of the DC converter circuit 101 to be the output terminal voltage of the DC combiner box 10 , wherein the output terminal voltage of the DC combiner box 10 It is detected by the detection circuit 102 when the input parameter of the DC combiner box 10 is not the preset input parameter value.
  • each DC combiner box in the power supply system 1 shown in FIG. 1b may further include a communication circuit, for details, please refer to another schematic structural diagram of the power supply system shown in FIG. 3 .
  • the DC combiner box 10 further includes a communication circuit 104 for receiving an instruction sent by the inverter 20 and sending the instruction to the controller 103 .
  • the communication mode between the communication circuit 104 and the inverter 20 may be power cable communication, dedicated wired communication, or wireless communication.
  • the controller 103 when the input terminal of the DC combiner box 10 is powered, the controller 103 starts to work, and at the same time controls the output voltage of the DC conversion circuit 101 to be the first preset voltage, and the output voltage of the DC conversion circuit 101 is In the case of the first preset voltage, the output current sampling signal is sent to the detection circuit 102 .
  • the detection circuit 102 collects the output terminal current of the DC combiner box 10 according to the output current sampling signal, and sends the output terminal current of the DC combiner box 10 to the controller 103 .
  • the controller 103 determines the output impedance value of the DC combiner box 10 according to the first preset voltage and the output current of the DC combiner box 10, and controls the DC conversion when the output impedance value of the DC combiner box 10 is greater than the preset output impedance threshold The output voltage of the circuit 101 is increased from the first preset voltage to the second preset voltage.
  • the controller 103 starts to work, and at the same time controls the output current of the DC conversion circuit 101 to be the first preset current, and the output current of the DC conversion circuit 101 is the first preset current.
  • the output voltage sampling signal is sent to the detection circuit 102 .
  • the detection circuit 102 collects the output terminal voltage of the DC combiner box 10 according to the output voltage sampling signal, and sends the output terminal voltage of the DC combiner box 10 to the controller 103 .
  • the controller 103 determines the output impedance value of the DC combiner box 10 according to the first preset current and the output terminal voltage of the DC combiner box 10, and controls the DC conversion when the output impedance value of the DC combiner box 10 is greater than the preset output impedance threshold
  • the output voltage of the circuit 101 is adjusted from the first preset voltage to the second preset voltage.
  • the controller 103 starts to work and sends output voltage and current sampling signals to the detection circuit 102 at the same time.
  • the detection circuit 102 collects the output terminal voltage and output terminal current of the DC combiner box 10 according to the output voltage and current sampling signal, and returns the output terminal voltage and output terminal current of the DC combiner box 10 to the controller 103 .
  • the controller 103 determines the output terminal voltage and output terminal current of the DC combiner box 10 according to the The output impedance value of the DC combiner box 10 is determined, and when the output impedance value of the DC combiner box 10 is greater than the preset output impedance threshold, the output voltage of the DC conversion circuit 101 is controlled to be the second preset voltage.
  • the controller 103 starts to work, and simultaneously sends the output residual current sampling signal to the detection circuit 102 .
  • the detection circuit 102 collects the output residual current of the DC combiner box 10 according to the output residual current sampling signal, and sends the output residual current of the DC combiner box 10 to the controller 103 .
  • the controller 103 controls the output voltage of the DC conversion circuit 101 to be the second preset voltage.
  • the input terminal of the inverter 20 obtains the same voltage, and the voltage is set to a value that enables the auxiliary power supply, the control unit and the communication unit of the inverter 20 to start working.
  • the inverter 20 sends an instruction to the communication circuit 104 of the DC combiner box 10, and the communication circuit 104 sends the instruction to the controller 103.
  • the controller 103 receives the instruction, it controls the output voltage of the DC conversion circuit 101 to change from the second
  • the preset voltage is adjusted to the third preset voltage, so that the DC combiner box 10 completes the startup.
  • the third preset voltage is generally the rated voltage of the DC conversion circuit 101 , and is greater than or equal to the second preset voltage.
  • the controller 103 may determine the connection relationship between the DC combiner box 10 and the inverter 20 according to the output impedance value of the DC combiner box 10 or the output residual current, and control the DC conversion circuit 101 to output the first output according to the connection relationship.
  • the second preset voltage ensures that the DC combiner box 10 can still start normally when it is difficult to communicate with the inverter 20 , which improves the stability of the power supply system 1 and has strong applicability.
  • the controller 103 no longer controls the output voltage of the DC conversion circuit 101 to continue to increase, but when an instruction sent by the inverter 20 is received Continue to control the DC conversion circuit 101 to complete the startup, which can effectively reduce the loss of the power supply system 1 and reduce the probability of misoperation of the power supply system 1 .
  • the present application also provides an output voltage control method for a DC combiner box, including:
  • the DC combiner box 10 further includes a communication circuit 104, and the communication circuit 104 is used for receiving the instruction sent by the inverter 20 and sending the instruction to the controller 103;
  • the controller 103 controls the output voltage of the DC conversion circuit 101 to be the second preset voltage, and controls the output of the DC conversion circuit 101 when receiving an instruction
  • the voltage is adjusted from the second preset voltage to a third preset voltage, wherein the third preset voltage is greater than or equal to the second preset voltage, and the third preset voltage is the rated voltage of the DC conversion circuit 101 .
  • the controller 103 when the input terminal of the DC combiner box 10 supplies power, the controller 103 starts to work, and when the controller 103 receives an instruction sent by the inverter 20 through the communication circuit 104 , the controller 103 controls The output voltage of the DC conversion circuit 101 is a third preset voltage, wherein the third preset voltage is the rated voltage of the DC conversion circuit 101 .
  • the inverter 20 has been provided with voltage by other DC combiner boxes, or provided with voltage by additional means such as the power grid, and sends an instruction to the communication circuit 104 of the DC combiner box 10 . Therefore, after receiving the instruction, the controller 103 can directly control the output voltage of the DC conversion circuit 101 to be the third preset voltage, so that the DC combiner box 10 can be started up.
  • FIG. 4 is another schematic structural diagram of the power supply system provided by the present application in which the output ends of the DC combiner box are connected in parallel.
  • the power supply system 1 includes a first group of DC combiner boxes 11 and a second group of DC combiner boxes 21 , a first inverter 30 and a second inverter 32 .
  • the first group of DC combiner boxes 11 includes a DC combiner box 11-1, a DC combiner box 11-2, ..., a DC combiner box 11-n
  • the second group of DC combiner boxes 21 includes a DC combiner box 21-1, a DC combiner box Boxes 21-2, ..., DC combiner boxes 21-m.
  • the output terminals of the DC combiner box 11-1, the DC combiner box 11-2, ..., and the DC combiner box 11-n are connected in parallel, and the DC combiner box 11-1, the DC combiner box 11-2, ..., and the DC combiner box
  • the positive output terminals of 11-n are coupled to form a first node 41, and the first node 41 is connected to the positive input terminal of the first inverter 31 through a first wire.
  • the DC combiner box 11 - 1 , the DC combiner box 11 - 2 , . . . and the negative output terminals of the DC combiner box 11 - n are coupled to form the second node 42 .
  • the output ends of the DC combiner box 21-1, the DC combiner box 21-2, ..., and the DC combiner box 21-m are connected in parallel, and the DC combiner box 21-1, the DC combiner box 21-2, ..., and the DC combiner box 21
  • the negative output terminal of -m is coupled to form a third node 43, and the third node 43 is connected to the negative input terminal of the second inverter 32 through a second wire.
  • the negative input terminal of the first inverter 31 is coupled with the positive input terminal of the second inverter 32 to form a fourth node 44, and the fourth node 44 and the second node 42 are connected through a third wire.
  • the flow capacity of the first wire and the flow capacity of the second wire are both greater than or equal to the flow capacity of the third wire.
  • the current of the third wire If the value is less than or equal to the current value of the first wire or the second wire, a wire with a lower current capacity can be selected, thereby saving cables and reducing the cost of the power supply system.
  • the output voltages (ie, the first preset voltage) of the DC combiner boxes in different groups in the maintenance mode can be the same or different; the DC combiner boxes of different groups are under maintenance
  • the output currents (ie, the first preset currents) in the modes may be the same or different.
  • each DC combiner box in the power supply system 1 and the specific implementation of controlling the output voltage of each DC combiner box please refer to the structure of the DC combiner box and the control of each DC combiner box in the embodiment shown in FIG. 1 b and FIG. 3 .
  • the specific implementation of the output voltage of the DC combiner box will not be repeated here.
  • the embodiment of the present application can realize the control of the output voltage of the DC combiner box according to the output terminal parameters of the DC combiner box, so as to ensure that the DC combiner box can still start and work normally even when it is difficult to communicate with the inverter.
  • the power supply system 1 is stable and has strong applicability.
  • by setting different groups of DC combiner boxes to have different output voltages in the maintenance mode it is possible to further determine whether the DC combiner boxes are connected to the correct group when testing the DC combiner boxes, thereby simplifying the detection of the power supply system 1 In this way, the maintenance cost of the power supply system 1 is reduced.
  • FIG. 5 is a schematic structural diagram of a power supply system in which the output ends of the DC combiner box provided in the present application are connected in series.
  • the power supply system 1 includes a DC combiner box 10 , a DC combiner box 11 , . . . ..., the DC power supply 100a is connected, the input end of the DC combiner box 11 is connected with the DC power supply 1101, the DC power supply 1102, ..., the DC power supply 110b, ..., the input end of the DC combiner box 1n is connected with the DC power supply 1n01, the DC power supply 1n02, ..., The DC power supply 1n0x is connected.
  • the negative output terminal of the DC combiner box 10 is connected to the positive output terminal of the DC combiner box 11, ..., the negative output terminal of the DC combiner box 1 (n-1) is connected to the positive output terminal of the DC combiner box 1n, and the The positive output terminal is connected to the positive input terminal of the inverter 20, the negative output terminal of the DC combiner box 1n is connected to the negative output terminal of the inverter 20, and the output terminal of the inverter 20 is connected to the AC grid.
  • the DC combiner box 10 includes a DC conversion circuit 101 , a detection circuit 102 and a controller 103 , wherein the input terminal of the DC conversion circuit 101 is coupled with the input terminal of the DC combiner box 10 , and the output terminal of the DC conversion circuit 101 passes through the detection circuit 102 and the DC link.
  • the output of the combiner box 10 is coupled.
  • the controller 103 can determine the connection relationship between the DC combiner box 10 and other DC combiner boxes in the power supply system 1 (corresponding to the DC combiner boxes 11 , . , and control the output voltage of the DC conversion circuit 101 according to the connection relationship.
  • the controller 103 when the input terminal of the DC combiner box 10 supplies power, the controller 103 starts to work, and simultaneously controls the output voltage of the DC conversion circuit 101 to be a first preset voltage, wherein the first preset voltage includes a DC voltage , AC voltage or DC voltage superimposed AC voltage.
  • the first preset voltage may be less than or equal to the safety voltage of the human body, such as 36V.
  • the controller 103 sends an output current sampling signal to the detection circuit 102 when the output voltage of the DC conversion circuit 101 is the first preset voltage.
  • the detection circuit 102 collects the output terminal current of the DC combiner box 10 according to the output current sampling signal, and returns the output terminal current of the DC combiner box 10 to the controller 103 .
  • the controller 103 determines the ratio between the first preset voltage and the output current of the DC combiner box 10 as the output impedance value of the DC combiner box 10, and compares the output impedance value of the DC combiner box 10 with the preset output impedance threshold. When the output impedance value of the DC combiner box 10 is greater than the preset output impedance threshold, it is determined that the DC combiner box 10 is connected to the inverter 20, and the output voltage of the DC conversion circuit 101 is controlled to be adjusted from the first preset voltage to a second preset voltage, wherein the second preset voltage is greater than the first preset voltage.
  • the controller 103 when the input terminal of the DC combiner box 10 supplies power, the controller 103 starts to work, and at the same time controls the output current of the DC conversion circuit 101 to be a first preset current, wherein the first preset current includes DC Current, alternating current or direct current superimposed alternating current.
  • the first preset current may be less than or equal to the safety current of the human body, or, when the output current of the DC conversion circuit 101 is the first preset current, the input voltage of the DC conversion circuit 101 may be less than or equal to the safety voltage of the human body.
  • the controller 103 sends an output voltage sampling signal to the detection circuit 102 when the output current of the DC conversion circuit 101 is the first preset current.
  • the detection circuit 102 collects the output terminal voltage of the DC combiner box 10 according to the output voltage sampling signal, and returns the output terminal voltage of the DC combiner box 10 to the controller 103 .
  • the controller 103 determines the ratio between the output terminal voltage of the DC combiner box 10 and the first preset current as the output impedance value of the DC combiner box 10, and compares the output impedance value of the DC combiner box 10 with the preset output impedance threshold value. When the output impedance value of the DC combiner box 10 is greater than the preset output impedance threshold, it is determined that the DC combiner box 10 is connected to the inverter 20, and the output voltage of the DC conversion circuit 101 is controlled to be the second preset voltage.
  • the controller 103 can further determine the connection relationship between the DC combiner box 10 and the DC combiner boxes 11, . . . , and the DC combiner box 1n by changing the preset output impedance threshold.
  • the controller 103 in order to enable the inverter 20 to obtain sufficient power and start normally, the controller 103 usually determines the number of the DC combiner box 10 connected to the inverter 20 and other DC combiner boxes connected to the DC combiner box 10 In the case of being larger than the preset number threshold, the output voltage of the DC conversion circuit 101 is controlled to be the second preset voltage.
  • the controller 103 can control the DC conversion circuit 101 to output the first preset voltage of the DC voltage superimposed on the AC voltage, and the detection circuit 102 detects that the output voltage of the DC conversion circuit 101 is DC when the output voltage is the first preset voltage.
  • the current at the output end of the combiner box 10 can effectively detect the magnitude of the resistive impedance, capacitive impedance and inductive impedance of the output end of the DC combiner box 10 .
  • the controller 103 can also control the DC conversion circuit 101 to output the first preset current of the DC current superimposed on the AC current, and detect the DC combiner box when the output current of the DC conversion circuit 101 is the first preset current through the detection circuit 102.
  • the output terminal voltage of 10 can effectively detect the resistive impedance, capacitive impedance and inductive impedance of the output terminal of the DC combiner box 10.
  • the controller 103 can determine whether the output end of the DC combiner box 10 is not based on the calculated output impedance value of the DC combiner box 10 .
  • the connection relationship between each DC combiner box and each inverter 20 in the power supply system 1 where the DC combiner box 10 is located can also be determined.
  • the controller 103 may determine the connection relationship between the DC combiner box 10 and the DC combiner box 11 , . . . , the DC combiner box 1n and the inverter 20 according to the calculated output impedance value of the DC combiner box 10 , and The output voltage of the DC conversion circuit 101 is controlled according to the connection relationship to ensure that the DC combiner box 10 can still start and work normally even when it is difficult to communicate with the inverter 20 , which improves the stability of the power supply system 1 and has strong applicability.
  • the present application also provides an output voltage control method for a DC combiner box, including:
  • the controller 103 controls the output voltage of the DC conversion circuit 101 to be the first preset voltage, and determines the output impedance value of the DC combiner box 10 according to the first preset voltage and the output current of the DC combiner box 10 .
  • the output voltage of the DC conversion circuit 101 is controlled to be the second preset voltage, wherein the output current of the DC combiner box 10 is determined by the detection circuit 102 at the output voltage of the DC conversion circuit 101 It is detected under the condition of the first preset voltage.
  • the controller 103 controls the output current of the DC conversion circuit 101 to be the first preset current, and determines the output impedance value of the DC combiner box 10 according to the first preset current and the output terminal voltage of the DC combiner box 10 .
  • the output impedance value of 10 is greater than the preset output impedance threshold
  • the output voltage of the DC conversion circuit 101 is controlled to be the second preset voltage, wherein the output terminal voltage of the DC combiner box 10 is determined by the detection circuit 102 in the DC conversion circuit 101. It is detected when the output current is the first preset current.
  • the controller 103 starts to work, and sends the output voltage and current to the detection circuit 102 at the same time sampled signal.
  • the detection circuit 102 collects the output terminal voltage and output terminal current of the DC combiner box 10 according to the output voltage and current sampling signal, and returns the output terminal voltage and output terminal current of the DC combiner box 10 to the controller 103 .
  • the controller 103 determines whether the output terminal voltage of the DC combiner box 10 satisfies the preset output voltage range (that is, greater than 0 and less than or equal to the first preset voltage), and the output terminal voltage of the DC combiner box 10 satisfies the preset output voltage In the case of the voltage range, it means that the DC combiner box 10 is connected to other DC combiner boxes in the power supply system 1, and that other DC combiner boxes connected to the DC combiner box 10 have already started to output the first preset voltage, and the DC combiner box 10 does not need to be any longer.
  • the preset output voltage range that is, greater than 0 and less than or equal to the first preset voltage
  • the controller 103 determines the ratio between the output terminal voltage of the DC combiner box 10 and the output terminal current as the output impedance value of the DC combiner box 10, and determines the output impedance value of the DC combiner box 10 as the output impedance value of the DC combiner box 10.
  • the output impedance is greater than the preset output impedance threshold, the output voltage of the DC conversion circuit 101 is controlled to be adjusted to the second preset voltage.
  • the controller 103 determines whether the output current of the DC combiner box 10 satisfies the preset output current range (that is, greater than 0 and less than or equal to the first preset current), and the output current of the DC combiner box 10 meets the preset output current range.
  • the controller 103 determines the ratio between the output terminal voltage of the DC combiner box 10 and the output terminal current as the output impedance value of the DC combiner box 10, and determines the output impedance of the DC combiner box 10 as the output impedance value of the DC combiner box 10.
  • the output voltage of the DC conversion circuit 101 is controlled to be adjusted to the second preset voltage.
  • the controller 103 does not need to output the first preset voltage when the output voltage of the DC combiner box 10 meets the preset output voltage range, or the current at the output terminal of the DC combiner box 10 meets the preset output voltage range. In the case of the preset output current range, there is no need to output the first preset current.
  • the output voltage of the circuit 101 further responds to the situation that other existing DC combiner boxes start to output voltage or current, and avoids that the DC combiner box 10 outputs voltage or current again and conflicts with the output voltage or current of other existing DC combiner boxes. problems, and ensure that the DC combiner box 10 can still start and work normally when it is difficult to communicate with the inverter 20 and other connected DC combiner boxes, which improves the stability of the power supply system 1 and has strong applicability.
  • the present application also provides an output voltage control method for a DC combiner box, including:
  • the DC combiner is determined according to the output terminal voltage and output terminal current of the DC combiner box 10
  • the output impedance value of the box 10 when the output impedance value of the DC combiner box 10 is greater than the preset output impedance threshold, the output voltage of the DC conversion circuit 101 is controlled to be the second preset voltage, wherein the output terminal of the DC combiner box 10
  • the voltage and the output terminal current are detected by the detection circuit 102 under the condition that the input parameters of the DC combiner box 10 are not the preset input parameter values.
  • the controller 103 starts to work, and sends the output residual current to the detection circuit 102 at the same time. sampled signal.
  • the detection circuit 102 collects the output residual current of the DC combiner box 10 according to the output residual current sampling signal, and returns the output residual current of the DC combiner box 10 to the controller 103 .
  • the controller 103 compares the output residual current of the DC combiner box 10 with the preset residual current threshold, and determines the DC combiner box 10 and the inverter 20 when the output residual current of the DC combiner box 10 is greater than the preset residual current threshold. connected, and the output voltage of the DC conversion circuit 101 is controlled to be the second preset voltage.
  • the controller 103 may determine the connection relationship between the DC combiner box 10 and the inverter 20 according to the output residual current of the DC combiner box 10, and control the output voltage of the DC conversion circuit 101 according to the connection relationship to ensure the DC
  • the combiner box 10 can still start and work normally even when it is difficult to communicate with the inverter 20 , which improves the stability of the power supply system 1 and has strong applicability.
  • the present application also provides an output voltage control method for a DC combiner box, including:
  • the controller 103 controls the output voltage of the DC conversion circuit 101 to be the second preset voltage, wherein the output residual current of the DC combiner box 10 is determined by the detection circuit. 102 is detected when the input parameter of the DC combiner box 10 is not the preset input parameter value.
  • the controller 103 starts to work, and at the same time sends the output voltage sample to the detection circuit 102 Signal.
  • the detection circuit 102 collects the output terminal voltage of the DC combiner box 10 according to the output voltage sampling signal, and returns the output terminal voltage of the DC combiner box 10 to the controller 103 .
  • the controller 103 determines whether the output terminal voltage of the DC combiner box 10 is greater than a preset output voltage threshold, wherein the preset output voltage threshold is greater than a first preset voltage. In the case that the output terminal voltage of the DC combiner box 10 is greater than the preset output voltage threshold, it means that the DC combiner box 10 is connected to other DC combiner boxes in the power supply system 1, and other DC combiner boxes connected to the DC combiner box 10 have started After startup, the controller 103 controls the output voltage of the DC conversion circuit 101 to adjust to the output terminal voltage of the DC combiner box 10 , that is, controls the output voltage of the DC conversion circuit 101 to follow the output terminal voltage of the DC combiner box 10 .
  • the controller 103 can determine that other DC combiner boxes connected to the DC combiner box 10 have started to start when the output voltage of the DC combiner box 10 is greater than the preset output voltage threshold, and then controls the DC conversion
  • the output voltage of the circuit 101 follows the output terminal voltage of the DC combiner box 10 , thereby avoiding the current impact problem caused by the high output terminal voltage when the DC combiner box 10 is not started, and ensuring that the DC combiner box 10 is connected with the inverter 20 .
  • other connected DC combiner boxes can still start and work normally even when it is difficult to communicate, which improves the stability of the power supply system 1 and has strong applicability.
  • the present application also provides an output voltage control method for a DC combiner box, including:
  • the output terminal parameters of the DC combiner box 10 include the output terminal voltage of the DC combiner box 10;
  • the controller 103 controls the output voltage of the DC converter circuit 101 to be the output terminal voltage of the DC combiner box 10 , wherein the output terminal voltage of the DC combiner box 10 It is detected by the detection circuit 102 when the input parameter of the DC combiner box 10 is not the preset input parameter value.
  • the controller 103 starts to work, and sends the output current and voltage to the detection circuit 102 at the same time. sampled signal.
  • the detection circuit 102 collects the output terminal current and output terminal voltage of the DC combiner box 10 according to the output current and voltage sampling signal, and returns the output terminal current and output terminal voltage of the DC combiner box 10 to the controller 103 .
  • the controller 103 determines whether the output current of the DC combiner box 10 is greater than a preset output current threshold, wherein the preset output current threshold is greater than a first preset current. In the case that the output current of the DC combiner box 10 is greater than the preset output current threshold, it means that the DC combiner box 10 is connected to other DC combiner boxes in the power supply system 1, and other DC combiner boxes connected to the DC combiner box 10 have started After startup, the controller 103 controls the output voltage of the DC conversion circuit 101 to adjust to the output terminal voltage of the DC combiner box 10 , that is, controls the output voltage of the DC conversion circuit 101 to follow the output terminal voltage of the DC combiner box 10 .
  • the controller 103 can determine that other DC combiner boxes connected to the DC combiner box 10 have started to start when the output current of the DC combiner box 10 is greater than the preset output current threshold, and then controls the DC converter
  • the output voltage of the circuit 101 follows the output terminal voltage of the DC combiner box 10 , thereby avoiding the current impact problem caused by the high output current when the DC combiner box 10 is not started, and ensuring that the DC combiner box 10 is connected to the inverter 20 .
  • other connected DC combiner boxes can still start and work normally even when it is difficult to communicate, which improves the stability of the power supply system 1 and has strong applicability.
  • the present application also provides an output voltage control method for a DC combiner box, including:
  • the output terminal parameters of the DC combiner box 10 include the output terminal current and output terminal voltage of the DC combiner box 10;
  • the controller 103 controls the output voltage of the DC conversion circuit 101 to be the output terminal voltage of the DC combiner box 10 , wherein the output current of the DC combiner box 10 and the output terminal voltage are detected by the detection circuit 102 under the condition that the input parameter of the DC combiner box 10 is not the preset input parameter value.
  • each DC combiner box in the power supply system 1 shown in FIG. 5 may further include a communication circuit.
  • the DC combiner box 10 further includes a communication circuit 104 for receiving an instruction sent by the inverter 20 and sending the instruction to the controller 103 .
  • the communication mode between the communication circuit 104 and the inverter 20 may be power cable communication, dedicated wired communication, or wireless communication.
  • the controller 103 when the input terminal of the DC combiner box 10 is powered, the controller 103 starts to work, and at the same time controls the output voltage of the DC conversion circuit 101 to be the first preset voltage, and the output voltage of the DC conversion circuit 101 is In the case of the first preset voltage, the output current sampling signal is sent to the detection circuit 102 .
  • the detection circuit 102 collects the output terminal current of the DC combiner box 10 according to the output current sampling signal, and sends the output terminal current of the DC combiner box 10 to the controller 103 .
  • the controller 103 determines the output impedance value of the DC combiner box 10 according to the first preset voltage and the output current of the DC combiner box 10, and controls the DC conversion when the output impedance value of the DC combiner box 10 is greater than the preset output impedance threshold The output voltage of the circuit 101 is increased from the first preset voltage to the second preset voltage.
  • the controller 103 starts to work, and at the same time controls the output current of the DC conversion circuit 101 to be the first preset current, and the output current of the DC conversion circuit 101 is the first preset current.
  • the output voltage sampling signal is sent to the detection circuit 102 .
  • the detection circuit 102 collects the output terminal voltage of the DC combiner box 10 according to the output voltage sampling signal, and sends the output terminal voltage of the DC combiner box 10 to the controller 103 .
  • the controller 103 determines the output impedance value of the DC combiner box 10 according to the first preset current and the output terminal voltage of the DC combiner box 10, and controls the DC conversion when the output impedance value of the DC combiner box 10 is greater than the preset output impedance threshold
  • the output voltage of the circuit 101 is adjusted from the first preset voltage to the second preset voltage.
  • the controller 103 starts to work and sends output voltage and current sampling signals to the detection circuit 102 at the same time.
  • the detection circuit 102 collects the output terminal voltage and output terminal current of the DC combiner box 10 according to the output voltage and current sampling signal, and returns the output terminal voltage and output terminal current of the DC combiner box 10 to the controller 103 .
  • the controller 103 determines the output terminal voltage and output terminal current of the DC combiner box 10 according to the The output impedance value of the DC combiner box 10 is determined, and when the output impedance value of the DC combiner box 10 is greater than the preset output impedance threshold, the output voltage of the DC conversion circuit 101 is controlled to be the second preset voltage.
  • the controller 103 starts to work, and simultaneously sends the output residual current sampling signal to the detection circuit 102 .
  • the detection circuit 102 collects the output residual current of the DC combiner box 10 according to the output residual current sampling signal, and sends the output residual current of the DC combiner box 10 to the controller 103.
  • the controller 103 controls the output voltage of the DC conversion circuit 101 to be the second preset voltage.
  • the input terminal of the inverter 20 obtains the same voltage, and the voltage is set to a value that enables the auxiliary power supply, the control unit and the communication unit of the inverter 20 to start working.
  • the inverter 20 sends an instruction to the communication circuit 104 of the DC combiner box 10, and the communication circuit 104 sends the instruction to the controller 103.
  • the controller 103 receives the instruction, it controls the output voltage of the DC conversion circuit 101 to change from the second
  • the preset voltage rises to the third preset voltage, so that the DC combiner box 10 completes the startup.
  • the third preset voltage is generally the rated voltage of the DC conversion circuit 101 , and is greater than or equal to the second preset voltage.
  • the controller 103 may determine the connection relationship between the DC combiner box 10 and the inverter 20 according to the output impedance value of the DC combiner box 10 or the output residual current, and control the DC conversion circuit 101 to output the first output according to the connection relationship.
  • the second preset voltage ensures that the DC combiner box 10 can still start normally when it is difficult to communicate with the inverter 20 , which improves the stability of the power supply system 1 and has strong applicability.
  • the controller 103 no longer controls the output voltage of the DC conversion circuit 101 to continue to increase, but when receiving the work instruction sent by the inverter 20 Continue to control the DC conversion circuit 101 to complete the startup until the next step, which can effectively reduce the loss of the power supply system 1 and reduce the probability of misoperation of the power supply system 1 .
  • the present application also provides an output voltage control method for a DC combiner box, including:
  • the DC combiner box 10 further includes a communication circuit 104, and the communication circuit 104 is used for receiving the instruction sent by the inverter 20 and sending the instruction to the controller 103;
  • the controller 103 controls the output voltage of the DC conversion circuit 101 to be the second preset voltage, and controls the output of the DC conversion circuit 101 when receiving an instruction
  • the voltage is adjusted from the second preset voltage to a third preset voltage, wherein the third preset voltage is greater than or equal to the second preset voltage, and the third preset voltage is the rated voltage of the DC conversion circuit 101 .
  • the controller 103 when the input terminal of the DC combiner box 10 supplies power, the controller 103 starts to work, and when the controller 103 receives an instruction sent by the inverter 20 through the communication circuit 104 , the controller 103 controls The output voltage of the DC conversion circuit 101 is a third preset voltage, wherein the third preset voltage is the rated voltage of the DC conversion circuit 101 .
  • the inverter 20 has been provided with voltage by other DC combiner boxes, or provided with voltage by additional means such as the power grid, and sends an instruction to the communication circuit 104 of the DC combiner box 10 . Therefore, after receiving the instruction, the controller 103 can directly control the output voltage of the DC conversion circuit 101 to be the third preset voltage, so that the DC combiner box 10 can be started up.
  • FIG. 7 is a schematic structural diagram of a power supply system in which the output ends of the DC combiner box are combined in series and parallel provided by the present application.
  • the power supply system 1 includes a first group of DC combiner boxes 11 , a second group of DC combiner boxes 21 and an inverter 31 .
  • the first group of DC combiner boxes 11 includes DC combiner boxes 11-1, . . . , DC combiner boxes 11-n
  • the second group of DC combiner boxes 21 includes DC combiner boxes 21-1,..., DC combiner boxes 21-m.
  • the negative output terminal of the DC combiner box 11-1 is connected in series with the positive output terminal of the DC combiner box 11-2, ..., the negative output terminal of the DC combiner box 11-(n-1) is connected with the positive output terminal of the DC combiner box 11-n
  • the positive output terminal of the DC combiner box 11 - 1 is connected to the positive input terminal of the inverter 31
  • the negative output terminal of the DC combiner box 11 - n is connected to the negative input terminal of the inverter 31 .
  • the positive output terminals of the DC combiner boxes 21-1, . . . and the DC combiner box 21-m are connected in parallel with the positive input terminal of the inverter 31.
  • the negative output terminal is connected in parallel with the negative input terminal of the inverter 31 .
  • each DC combiner box in the first group of DC combiner boxes 11 and the specific implementation of controlling the output voltage of each DC combiner box please refer to the DC combiner boxes in the embodiments shown in FIG. 5 and FIG. 6 .
  • the structure and the specific implementation of controlling the output voltage of each DC combiner box, the structure of each DC combiner box in the second group of DC combiner boxes 21 and the specific implementation of controlling the output voltage of each DC combiner box please refer to FIG. 1b and FIG. 3 .
  • the structure of the DC combiner box in the illustrated embodiment and the specific implementation manner of controlling the output voltage of each DC combiner box will not be repeated here.
  • the embodiment of the present application can realize the control of the output voltage of the DC combiner box according to the output terminal parameters of the DC combiner box, so as to ensure that the DC combiner box can still start and work normally even when it is difficult to communicate with the inverter.
  • the stability and applicability of the power supply system 1 are strong.
  • the controller in the DC combiner box can output the DC combiner box.
  • the connection of other DC combiner boxes or inverters is recorded. Under normal circumstances, the connection relationship between the DC combiner boxes and the inverter will not change after the power supply system is installed. Therefore, when any DC combiner box is started for the second time and thereafter, the controller in the DC combiner box can complete the startup of the DC combiner box according to the recorded connection of the output terminals.
  • the controller in any DC combiner box in the power supply system can be started according to the first startup method of the DC combiner box (that is, as shown in Figure 1b- Figure 7).
  • the starting mode of the DC combiner box in the embodiment is started.
  • the controller determines the connection relationship between the DC combiner box and other DC combiner boxes or inverters in the power supply system according to the output terminal parameters of the DC combiner box, and then can control the output voltage of the DC conversion circuit according to the connection relationship. , to ensure that the DC combiner box can still start and work normally when it is difficult to communicate with the inverter, which improves the stability of the power supply system and has strong applicability.

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Abstract

本申请提供了一种供电系统及直流汇流箱的输出电压控制方法，供电系统包括至少一个直流汇流箱和逆变器，至少一个直流汇流箱中各个直流汇流箱的输出端串联和/或并联后与逆变器的输入端耦合，各个直流汇流箱的输入端与直流电源相连，直流汇流箱包括控制器、检测电路和直流变换电路，其中，直流变换电路将直流汇流箱的输入端电压直流变换为直流汇流箱的输出端电压。检测电路检测直流汇流箱的输出端参数，并将直流汇流箱的输出端参数发送至控制器，控制器根据直流汇流箱的输出端参数，控制直流变换电路的输出电压。采用本申请，可保证直流汇流箱在与逆变器难以通信的情况下依然可以正常启动和工作，提高了供电系统的稳定性，适用性强。

Description

供电系统及直流汇流箱的输出电压控制方法
本申请要求于2021年03月30日提交中国专利局、申请号为202110339587.9、申请名称为“供电系统及直流汇流箱的输出电压控制方法”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及电子电路技术领域，尤其涉及一种供电系统及直流汇流箱的输出电压控制方法。
背景技术
目前，如图1a所示，供电系统包括多个直流电源、多个直流汇流箱以及逆变器，其中，每个直流汇流箱的输入端与至少一个直流电源相连，输出端与逆变器相连，每个直流汇流箱用于将与其输入端相连的至少一个直流电源的直流电进行直流变换后输出至逆变器。
如图1a所示，在直流汇流箱的输出电压控制方式中，逆变器向直流汇流箱发送通信信号，直流汇流箱根据接收到的通信信号控制自身的输出电压，从而实现直流汇流箱的启动，并为逆变器提供电能。但是上述方式存在以下问题：在直流汇流箱与逆变器之间难以通信(如通信信号被吸收或者被遮挡等通信链路异常，或者逆变器未获得电能无法发送通信信号)的情况下，会导致直流汇流箱无法正常启动和工作，进而导致供电系统稳定性差。
发明内容
本申请提供了一种供电系统及直流汇流箱的输出电压控制方法，直流汇流箱可根据自身的输出端参数确定自身与其他直流汇流箱或者逆变器的连接关系，进而可根据该连接关系控制自身的输出电压，保证直流汇流箱在与逆变器难以通信的情况下依然可以正常启动和工作，提高了供电系统的稳定性，适用性强。
第一方面，本申请提供了一种供电系统，该供电系统包括至少一个直流汇流箱和逆变器，至少一个直流汇流箱中各个直流汇流箱的输出端串联和/或并联后与逆变器的输入端耦合，各个直流汇流箱的输入端与直流电源相连，直流汇流箱包括控制器、检测电路和直流变换电路，其中，直流变换电路的输入端与直流汇流箱的输入端耦合，直流变换电路的输出端与直流汇流箱的输出端耦合，直流变换电路用于将直流汇流箱的输入端电压直流变换为直流汇流箱的输出端电压。检测电路检测直流汇流箱的输出端参数，并将直流汇流箱的输出端参数发送至控制器，控制器根据直流汇流箱的输出端参数，控制直流变换电路的输出电压。进而，直流汇流箱可根据输出端参数，确定该直流汇流箱与其他直流汇流箱或者逆变器的连接关系，并根据该连接关系控制直流变换电路的输出电压，保证直流汇流箱在与逆变器难以通信的情况下依然可以正常启动和工作，提高了供电系统的稳定性，适用性强。
结合第一方面，在第一种可能的实施方式中，控制器根据第一预设电压以及直流汇 流箱的输出端电流确定直流汇流箱的输出阻抗值，在直流汇流箱的输出阻抗值大于预设输出阻抗阈值的情况下，确定该直流汇流箱与逆变器相连，进而控制直流变换电路的输出电压从第一预设电压调整为第二预设电压。
结合第一方面，在第二种可能的实施方式中，第一预设电压为直流电压、交流电流或者直流电压叠加交流电压。进而，直流汇流箱可在第一预设电压为直流电压的情况下，计算得到直流汇流箱的输出阻抗值中阻性部分阻抗值；在第一预设电压为交流电压的情况下，计算得到直流汇流箱的输出阻抗值中容性部分阻抗值和感性部分阻抗值；在第一预设电压为直流电压叠加交流电压的情况下，计算得到直流汇流箱的输出阻抗值中阻性部分阻抗值、容性部分阻抗值和感性部分阻抗值。
结合第一方面，在第三种可能的实施方式中，直流汇流箱可根据第一预设电流以及直流汇流箱的输出端电压确定直流汇流箱的输出阻抗值，并在直流汇流箱的输出阻抗值大于预设输出阻抗阈值的情况下，确定该直流汇流箱与逆变器相连，进而控制直流变换电路的输出电压为第二预设电压。
结合第一方面，在第四种可能的实施方式中，第一预设电流为直流电流、交流电流或者直流电流叠加交流电流。进而，直流汇流箱可在第一预设电流为直流电流的情况下，计算得到直流汇流箱的输出阻抗值中阻性部分阻抗值；在第一预设电流为交流电流的情况下，计算得到直流汇流箱的输出阻抗值中容性部分阻抗值和感性部分阻抗值；在第一预设电流为直流电流叠加交流电流的情况下，计算得到直流汇流箱的输出阻抗值中阻性部分阻抗值、容性部分阻抗值和感性部分阻抗值。
结合第一方面，在第五种可能的实施方式中，直流汇流箱在输出端电压满足预设输出电压范围或者输出端电流满足预设输出电流范围的情况下，根据直流汇流箱的输出端电压和输出端电流确定直流汇流箱的输出阻抗值，在直流汇流箱的输出阻抗值大于预设输出阻抗阈值的情况下，确定该直流汇流箱与逆变器相连，进而控制直流汇流箱中直流变换电路的输出电压调整为第二预设电压。
结合第一方面，在第六种可能的实施方式中，直流汇流箱的输出端电压包括直流电压和/或交流电压，输出端电流包括直流电流和/或交流电流。进而，直流汇流箱可在输出端电压和输出端电流均为直流电的情况下，计算得到直流汇流箱的输出阻抗值中阻性部分阻抗值；在输出端电压和输出端电流均交流电的情况下，计算得到直流汇流箱的输出阻抗值中容性部分阻抗值和感性部分阻抗值；在输出端电压和输出端电流均为直流电叠加交流电的情况下，计算得到直流汇流箱的输出阻抗值中阻性部分阻抗值、容性部分阻抗值和感性部分阻抗值。
结合第一方面，在第七种可能的实施方式中，直流汇流箱可以在直流汇流箱的输出残余电流大于预设残余电流阈值的情况下，确定该直流汇流箱与逆变器相连，并控制直流变换电路的输出电压为第二预设电压。
结合第一方面，在第八种可能的实施方式中，直流汇流箱还包括通信电路，通信电路用于接收逆变器发送的指令，并将指令发送至控制器。控制器在接收到指令的情况下，控制直流变换电路的输出电压为第三预设电压，其中，第三预设电压大于或者等于第二预设电压，并且，第三预设电压为直流变换电路的额定电压。进而，直流汇流箱在控制直流变换电路的输出电压为第二预设电压后，不再对直流变换电路的输出电压进行改变，直到接收到逆变器发送的指令后，控制直流变换电路的输出电压由第二预设电压调整为额定电压，从而使直流汇流箱完成启动。此外，在直流变换电路的输出电压为第二预设 电压时，直流汇流箱不再控制直流变换电路的输出电压继续升高，而是在接收到逆变器发送的指令的情况下才继续控制直流变换电路完成启动，可有效减少供电系统的损耗，降低供电系统误操作的几率。
结合第一方面，在第九种可能的实施方式中，直流变换电路包括功率变换电路、电压调节电路和分断开关，功率变换电路的输出电压大于电压调节电路的输出电压，其中，功率变换电路的输入端通过分断开关与直流变换电路的输入端耦合，功率变换电路的输出端与直流变换电路的输出端耦合；电压调节电路的输入端与直流变换电路的输入端耦合，电压调节电路的输出端与直流变换电路的输出端耦合。直流汇流箱可通过控制分断开关断开，并且，控制电压调节电路的输出电压为第一预设电压，使得直流汇流箱的输出电压为第一预设电压。进而，使得在功率变换电路不具有降压功能的情况下，直流变换电路仍然可以实现输出值为第一预设电压的低电压。
结合第一方面，在第十种可能的实施方式中，直流汇流箱可在输出端电压大于预设输出电压阈值的情况下，确定该直流汇流箱与其他直流汇流箱相连，并且，与该直流汇流箱相连的其他直流汇流箱已经开始启动，此时，直流汇流箱控制直流变换电路的输出电压跟随直流汇流箱的输出端电压进行输出，进而避免了当前直流汇流箱未启动时输出端电压已经过高带来的电流冲击问题，并保证当前直流汇流箱在与逆变器及其他相连直流回流箱难以通信的情况下依然可以正常启动和工作。
结合第一方面，在第十一种可能的实施方式中，直流汇流箱可在输出端电流大于预设输出电流阈值的情况下，确定该直流汇流箱与其他直流汇流箱相连，并且，与该直流汇流箱相连的其他直流汇流箱已经开始启动，此时，直流汇流箱控制直流变换电路的输出电压跟随直流汇流箱的输出端电压进行输出，进而避免了当前直流汇流箱未启动时输出端电压已经过高带来的电流冲击问题，并保证当前直流汇流箱在与逆变器及其他相连直流回流箱难以通信的情况下依然可以正常启动和工作。
结合第一方面，在第十二种可能的实施方式中，逆变器包括第一逆变器和第二逆变器，至少一个直流汇流箱包括第一组直流汇流箱和第二组直流汇流箱，第一组直流汇流箱和第二组直流汇流箱均包括至少一个直流汇流箱，其中：第一组直流汇流箱中各个直流汇流箱的输出端并联，第二组直流汇流箱中各个直流汇流箱的输出端并联；第一组直流汇流箱中各个直流汇流箱的第一输出端耦合，构成第一节点；第一节点与第一逆变器的第一输入端通过第一导线连接；第一组直流汇流箱中各个直流汇流箱的第二输出端与第二组直流汇流箱中各个直流汇流箱的第一输出端耦合，构成第二节点；第二组直流汇流箱中各个直流汇流箱的第二输出端耦合，构成第三节点；第三节点与第二逆变器的第二输入端通过第二导线连接；第一逆变器的第二输入端与第二逆变器的第一输入端耦合，构成第四节点；第四节点与第二节点通过第三导线连接，其中，第一导线的通流能力和第二导线的通流能力均大于或者等于于第三导线的通流能力。上述直流汇流箱的输出电压控制方法同样适用于本申请实施例中提供的供电系统，由于第三导线上同时流过第一组直流汇流箱的输出电流和第二组直流汇流箱的输出电流，并且方向相反，存在抵消的现象，因此在正常的工作模式下，第三导线的电流值小于或等于第一导线或者第二导线的电流值，可以选取通流能力较低的导线，从而节省线缆，降低供电系统的成本。
结合第一方面，在第十三种可能的实施方式中，第一组直流汇流箱在维护模式下的输出电压与第二组直流汇流箱在维护模式下的输出电压不同，并且，第一组直流汇流箱中各个直流汇流箱在维护模式下的输出电压相同，第二组直流汇流箱中各个直流汇流箱 在维护模式下的输出电压相同。进而，通过设置不同组的直流汇流箱在维护模式下的输出电压不同，可以在对直流汇流箱进行测试时，进一步判断出直流汇流箱是否连接至正确的分组，从而简化了供电系统的检测方式，降低了供电系统的维护成本。
结合第一方面，在第十四种可能的实施方式中，直流电源为光伏组串，进而，该供电系统的应用场景为光伏场景。
第二方面，本申请提供了一种直流汇流箱的输出电压控制方法，该方法适用于供电系统，该供电系统包括至少一个直流汇流箱和逆变器，至少一个直流汇流箱中各个直流汇流箱的输出端串联和/或并联后与逆变器的输入端耦合，各个直流汇流箱的输入端与直流电源相连，直流汇流箱包括控制器、检测电路和直流变换电路，其中，直流变换电路的输入端与直流汇流箱的输入端耦合，直流变换电路的输出端与直流汇流箱的输出端耦合，直流变换电路将直流汇流箱的输入端电压直流变换为直流汇流箱的输出端电压。检测电路检测直流汇流箱的输出端参数，并将直流汇流箱的输出端参数发送至控制器，控制器根据直流汇流箱的输出端参数，控制直流变换电路的输出电压。
结合第二方面，在第一种可能的实施方式中，控制器根据第一预设电压以及直流汇流箱的输出端电流确定直流汇流箱的输出阻抗值，在直流汇流箱的输出阻抗值大于预设输出阻抗阈值的情况下，确定该直流汇流箱与逆变器相连，进而控制直流变换电路的输出电压从第一预设电压调整为第二预设电压。
结合第二方面，在第二种可能的实施方式中，第一预设电压为直流电压、交流电压或者直流电压叠加交流电压。
结合第二方面，在第三种可能的实施方式中，直流汇流箱可根据第一预设电流以及直流汇流箱的输出端电压确定直流汇流箱的输出阻抗值，并在直流汇流箱的输出阻抗值大于预设输出阻抗阈值的情况下，确定该直流汇流箱与逆变器相连，进而控制直流变换电路的输出电压为第二预设电压。
结合第二方面，在第四种可能的实施方式中，第一预设电流为直流电流、交流电流或者直流电流叠加交流电流。
结合第二方面，在第五种可能的实施方式中，直流汇流箱在输出端电压满足预设输出电压范围或者输出端电流满足预设输出电流范围的情况下，根据直流汇流箱的输出端电压和输出端电流确定直流汇流箱的输出阻抗值，在直流汇流箱的输出阻抗值大于预设输出阻抗阈值的情况下，确定该直流汇流箱与逆变器相连，进而控制直流汇流箱中直流变换电路的输出电压调整为第二预设电压。
结合第二方面，在第六种可能的实施方式中，直流汇流箱的输出端电压包括直流电压和/或交流电压，输出端电流包括直流电流和/或交流电流。
结合第二方面，在第七种可能的实施方式中，直流汇流箱可以在输出残余电流大于预设残余电流阈值的情况下，确定该直流汇流箱与逆变器相连，并控制直流变换电路的输出电压为第二预设电压。
结合第二方面，在第八种可能的实施方式中，直流汇流箱还包括通信电路，通信电路用于接收逆变器发送的指令，并将指令发送至控制器。控制器在接收到指令的情况下，控制直流变换电路的输出电压为第三预设电压，其中，第三预设电压大于或者等于第二预设电压，并且，第三预设电压为直流变换电路的额定电压。
结合第二方面，在第九种可能的实施方式中，直流变换电路包括功率变换电路、电压调节电路和分断开关，功率变换电路的输出电压大于电压调节电路的输出电压，其中， 功率变换电路的输入端通过分断开关与直流变换电路的输入端耦合，功率变换电路的输出端与直流变换电路的输出端耦合；电压调节电路的输入端与直流变换电路的输入端耦合，电压调节电路的输出端与直流变换电路的输出端耦合。直流汇流箱可通过控制分断开关断开，并且，控制电压调节电路的输出电压为第一预设电压，使得直流汇流箱的输出电压为第一预设电压。
结合第二方面，在第十种可能的实施方式中，直流汇流箱在输出端电压大于预设输出电压阈值的情况下，确定该直流汇流箱与其他直流汇流箱相连，并且，与该直流汇流箱相连的其他直流汇流箱已经开始启动，此时，直流汇流箱控制直流变换电路的输出电压跟随直流汇流箱的输出端电压进行输出。
结合第二方面，在第十一种可能的实施方式中，直流汇流箱在输出端电流大于预设输出电流阈值的情况下，确定该直流汇流箱与其他直流汇流箱相连，并且，与该直流汇流箱相连的其他直流汇流箱已经开始启动，此时，直流汇流箱控制直流变换电路的输出电压跟随直流汇流箱的输出端电压进行输出。
结合第二方面，在第十二种可能的实施方式中，逆变器包括第一逆变器和第二逆变器，至少一个直流汇流箱包括第一组直流汇流箱和第二组直流汇流箱，第一组直流汇流箱和第二组直流汇流箱均包括至少一个直流汇流箱，其中：第一组直流汇流箱中各个直流汇流箱的输出端并联，第二组直流汇流箱中各个直流汇流箱的输出端并联；第一组直流汇流箱中各个直流汇流箱的第一输出端耦合，构成第一节点；第一节点与第一逆变器的第一输入端通过第一导线连接；第一组直流汇流箱中各个直流汇流箱的第二输出端与第二组直流汇流箱中各个直流汇流箱的第一输出端耦合，构成第二节点；第二组直流汇流箱中各个直流汇流箱的第二输出端耦合，构成第三节点；第三节点与第二逆变器的第二输入端通过第二导线连接；第一逆变器的第二输入端与第二逆变器的第一输入端耦合，构成第四节点；第四节点与第二节点通过第三导线连接，其中，第一导线的通流能力和第二导线的通流能力均大于或者等于第三导线的通流能力。
结合第二方面，在第十三种可能的实施方式中，第一组直流汇流箱在维护模式下的输出电压与第二组直流汇流箱在维护模式下的输出电压不同，并且，第一组直流汇流箱中各个直流汇流箱在维护模式下的输出电压相同，第二组直流汇流箱中各个直流汇流箱在维护模式下的输出电压相同。
结合第二方面，在第十四种可能的实施方式中，直流电源为光伏组串。应理解的是，本申请上述多个方面的实现和有益效果可互相参考。
附图说明
图1a是现有技术提供的一种直流汇流箱的输出电压控制方法；
图1b是本申请提供的直流汇流箱的输出端并联的供电系统的一结构示意图；
图2a是本申请提供的直流变换电路的一结构示意图；
图2b是本申请提供的直流变换电路的另一结构示意图；
图3是本申请提供的直流汇流箱的输出端并联的供电系统的另一结构示意图；
图4是本申请提供的直流汇流箱的输出端并联的供电系统的又一结构示意图；
图5是本申请提供的直流汇流箱的输出端串联的供电系统的一结构示意图；
图6是本申请提供的直流汇流箱的输出端串联的供电系统的另一结构示意图；
图7是本申请提供的直流汇流箱的输出端串并联组合的供电系统的结构示意图。
具体实施方式
本申请提供的供电系统及直流汇流箱的输出电压控制方法可适用于以下场景：
在一可选实施例中，本申请的技术方案可以应用于光伏场景，则本申请提供的供电系统中的直流电源为光伏组串，每个光伏组串可以包括多个串联和/或并联的光伏组件。供电系统还包括至少一个直流汇流箱和逆变器，至少一个直流汇流箱的输出端串联和/或并联后与逆变器的输入端耦合，每个直流汇流箱的输入端与至少一个光伏组串相连，用于将与其相连的光伏组串产生的直流电经过升压后输出至逆变器，逆变器用于将直流汇流箱产生的经过升压后的直流电经过逆变转换成符合电网要求的交流电。供电系统可以将逆变后的交流电输向电网。在可选的实施场景中，供电系统还可以应用于不间断供电电源的场景中，即供电系统中可以设置有储能电池，例如镍镉电池、镍氢电池、锂离子电池、锂聚合物电池等。
直流汇流箱包括检测电路、直流变换电路和控制器。检测电路检测直流汇流箱的输出端参数，并将直流汇流箱的输出端参数发送至控制器，控制器根据直流汇流箱的输出端参数，确定该直流汇流箱与供电系统中其他直流汇流箱或者逆变器的连接关系，进而可根据该连接关系控制直流变换电路的输出电压，保证直流汇流箱在与逆变器难以通信的情况下依然可以正常启动和工作，提高了供电系统的稳定性，适用性强。
在另一可选实施例中，本申请的技术方案也可以应用于多机并联的光伏场景，则本申请提供的供电系统中的直流电源既可以为光伏组串，也可以为储能电池组串，每个储能电池组串可以包括多个串联和/或并联的储能电池。供电系统还包括至少一个直流汇流箱和逆变器，至少一个直流汇流箱的输出端串联和/或并联后与逆变器的输入端耦合，直流汇流箱的输入端可以与至少一个光伏组串相连，用于将与其相连的光伏组串产生的直流电经过升压后输出至逆变器；直流汇流箱的输入端也可以与至少一个储能电池组串相连，用于将与其相连的储能电池组串产生的直流电经过直流变换后输出至逆变器。示例性的，供电系统共包括第一直流汇流箱和第二直流汇流箱，其中，第一直流汇流箱与至少一个光伏组串相连，第二直流汇流箱与至少一个储能电池组串相连。逆变器用于将直流汇流箱产生的经过升压或者直流变换后的直流电经过逆变转换成符合电网要求的交流电。供电系统可以将逆变后的交流电输向电网。在可选的实施场景中，供电系统还可以应用于不间断供电电源的场景中，即供电系统中可以设置有储能电池，例如镍镉电池、镍氢电池、锂离子电池、锂聚合物电池等。
直流汇流箱包括检测电路、直流变换电路和控制器。检测电路检测直流汇流箱的输出端参数，并将直流汇流箱的输出端参数发送至控制器，控制器根据直流汇流箱的输出端参数，确定该直流汇流箱与供电系统中其他直流汇流箱或者逆变器的连接关系，进而可根据该连接关系控制直流变换电路的输出电压，保证直流汇流箱在与逆变器难以通信的情况下依然可以正常启动和工作，提高了供电系统的稳定性，适用性强。
在又一可选实施例中，本申请的技术方案还可以应用于电池充/放电场景，则本申请提供的供电系统中的直流电源为储能电池组串，每个储能电池组串可以包括多个串联和/或并联的储能电池。供电系统还包括至少一个直流汇流箱和逆变器，至少一个直流汇流箱的输出端串联和/或并联后与逆变器的输入端耦合，直流汇流箱的输入端与至少一个储能电池组串相连，用于将与其相连的储能电池组串产生的直流电经过直流变换后输出至逆变器。逆变器用于将直流汇流箱产生的经过直流变换后的直流电经过逆变转换成符合电网要求的交流电。供 电系统可以将逆变后的交流电输向电网。
直流汇流箱包括检测电路、直流变换电路和控制器。检测电路检测直流汇流箱的输出端参数，并将直流汇流箱的输出端参数发送至控制器，控制器根据直流汇流箱的输出端参数，确定该直流汇流箱与供电系统中其他直流汇流箱或者逆变器的连接关系，进而可根据该连接关系控制直流变换电路的输出电压，保证直流汇流箱在与逆变器难以通信的情况下依然可以正常启动和工作，提高了供电系统的稳定性，适用性强。
上述只是对本申请提供的供电系统的应用场景进行示例，而非穷举，本申请不对应用场景进行限制。
参见图1b，图1b是本申请提供的直流汇流箱的输出端并联的供电系统的一结构示意图。如图1b所示，供电系统1包括直流汇流箱10、直流汇流箱11、…、直流汇流箱1n以及逆变器20，其中，直流汇流箱10的输入端与直流电源1001、直流电源1002、…、直流电源100a相连，直流汇流箱11的输入端与直流电源1101、直流电源1102、…、直流电源110b相连，…，直流汇流箱1n的输入端与直流电源1n01、直流电源1n02、…、直流电源1n0x相连，直流汇流箱10、直流汇流箱11、…、以及直流汇流箱1n的输出端并联后通过连接导线与逆变器20的输入端相连，逆变器20的输出端连接交流电网。
由于供电系统1中每个直流汇流箱的结构以及其输出电压控制方式均相同，下面以直流汇流箱10为例进行说明。直流汇流箱10包括直流变换电路101、检测电路102和控制器103，其中，直流变换电路101的输入端与直流汇流箱10的输入端耦合，直流变换电路101的输出端经过检测电路102与直流汇流箱10的输出端耦合。
控制器103可根据直流汇流箱10的输出端参数，确定直流汇流箱10与供电系统1中其他直流汇流箱(对应直流汇流箱11、…、直流汇流箱1n)或者逆变器20的连接关系，并根据该连接关系控制直流变换电路101的输出电压。
在一可选实施例中，当直流汇流箱10输入端供电时，控制器103开始工作，同时控制直流变换电路101的输出电压为第一预设电压，其中，第一预设电压包括直流电压、交流电压或者直流电压叠加交流电压。第一预设电压可以为小于或者等于人体的安全电压，例如36V。
在一可选实施方式中，参见图2a，图2a是本申请提供的直流变换电路的一结构示意图。如图2a所示，直流变换电路101包括主功率电路1011(如Buck-Boost变换电路)，主功率电路1011中的可控开关管与控制器相连。
在第一预设电压为直流电压的情况下，控制器103可以通过向主功率电路1011中的可控开关管输出相应的占空比固定的脉宽调制波，以使直流变换电路101的输出电压为第一预设电压。
在第一预设电压为交流电压的情况下，控制器103可以通过向主功率电路1011中的可控开关管输出相应的占空比不断变化的脉宽调制波，并且，控制占空比的变化频率低于可控开关管的开关频率，以使直流变换电路101的输出电压为第一预设电压。
在第一预设电压为直流电压叠加交流电压的情况下，控制器103可以通过向主功率电路1011中的可控开关管输出相应的占空比在固定值附近不断变化的脉宽调制波，并且，控制占空比的变化频率低于可控开关管的开关频率，以使直流变换电路101的输出电压为第一预设电压。
在另一可选实施方式中，参见图2b，图2b是本申请提供的直流变换电路的另一结构示 意图。如图2b所示，直流变换电路101包括分断开关1012、功率变换电路1013和电压调节电路1013，其中，功率变换电路1013不具有降压功能，并且，功率变换电路1013的输出电压大于电压调节电路1014的输出电压。功率变换电路1013的输入端通过分断开关1012与直流变换电路101的输入端耦合，输出端与直流变换电路101的输出端耦合；电压调节电路1014的输入端与直流变换电路101的输入端耦合，输出端与直流变换电路101的输出端耦合。由于功率变换电路1013(如Boost变换电路)自身无法输出较低的电压，并且在直流变换电路101输入电压较高时，功率变换电路1013的输出电压还有可能会跟随直流变换电路101的输入电压从而达到较高值，因此，需要在直流变换电路101输入端和功率变换电路1013输入端之间增加分断开关1012以断开，并且增加耦合在直流变换电路101输入端和输出端之间的电压调节电路1014。具体的，控制器103通过控制分断开关1012断开，使功率变换电路1013不工作，同时，控制电压调节电路1014输出电压为第一预设电压，以使直流变换电路101的输出电压为第一预设电压。该电压调节电路1014可以是额外增加的电路，也可以与直流变换电路101中的预充电电路、软启动电路、电势诱导衰减电路等共用。这里，控制器103控制直流变换电路101输出的第一预设电压为直流电压、交流电压或者直流电压叠加交流电压的具体实现方式可参照图2a所示实施例中控制器103控制直流变换电路101输出的第一预设电压为直流电压、交流电压或者直流电压叠加交流电压的具体实现方式，此处不再赘述。
之后，控制器103在直流变换电路101的输出电压为第一预设电压的情况下，向检测电路102发送输出电流采样信号。检测电路102根据输出电流采样信号采集直流汇流箱10的输出端电流，并将直流汇流箱10的输出端电流返回至控制器103。控制器103将第一预设电压与直流汇流箱10的输出端电流之间的比值确定为直流汇流箱10的输出阻抗值，并比较直流汇流箱10的输出阻抗值与预设输出阻抗阈值的大小，在直流汇流箱10的输出阻抗值大于预设输出阻抗阈值的情况下，确定直流汇流箱10与逆变器20相连，并控制直流变换电路101的输出电压从第一预设电压调整为第二预设电压，其中，第二预设电压大于第一预设电压。这里，控制器103控制直流变换电路101的输出电压为第二预设电压的具体实现方式可参照本申请实施例中控制器103控制直流变换电路101的输出电压为第一预设电压的具体实现方式，此处不再赘述。
在另一可选实施例中，当直流汇流箱10输入端供电时，控制器103开始工作，同时控制直流变换电路101的输出电流为第一预设电流，其中，第一预设电流包括直流电流、交流电流或者直流电流叠加交流电流。第一预设电流可以为小于或者等于人体的安全电流，或者，当直流变换电路101的输出电流为第一预设电流时，直流变换电路101的输入电压为小于或者等于人体的安全电压。这里，控制器103控制直流变换电路101的输出电流为第一预设电流的具体实现方式，请参照上一实施例中控制器103直流变换电路101的输出电压为第一预设电压的具体实现方式，此处不再赘述。
之后，控制器103在直流变换电路101的输出电流为第一预设电流的情况下，向检测电路102发送输出电压采样信号。检测电路102根据输出电压采样信号采集直流汇流箱10的输出端电压，并将直流汇流箱10的输出端电压返回至控制器103。控制器103将直流汇流箱10的输出端电压与第一预设电流之间的比值确定为直流汇流箱10的输出阻抗值，并比较直流汇流箱10的输出阻抗值与预设输出阻抗阈值的大小，在直流汇流箱10的输出阻抗值大于预设输出阻抗阈值的情况下，确定直流汇流箱10与逆变器20相连， 并控制直流变换电路101的输出电压为第二预设电压。这里，控制器103控制直流变换电路101的输出电压为第二预设电压的具体实现方式可参照本申请实施例中控制器103控制直流变换电路101的输出电压为第一预设电压的具体实现方式，此处不再赘述。
需要说明的是，控制器103可以通过改变预设输出阻抗阈值大小的方式，进一步确定直流汇流箱10与直流汇流箱11、…、以及直流汇流箱1n的连接关系。此外，为了使逆变器20能够获得足够的电能并正常启动，控制器103通常是在确定直流汇流箱10与逆变器20相连，并且，与直流汇流箱10相连的其他直流汇流箱的数量大于预设数量阈值的情况下，控制直流变换电路101的输出电压为第二预设电压。
进一步地，控制器103可通过控制直流变换电路101输出直流电压叠加交流电压的第一预设电压，并且通过检测电路102检测得到直流变换电路101的输出电压为第一预设电压的情况下直流汇流箱10的输出端电流，有效检测出直流汇流箱10输出端的阻性阻抗、容性阻抗、感性阻抗的大小情况。控制器103也可通过控制直流变换电路101输出直流电流叠加交流电流的第一预设电流，并且通过检测电路102检测得到直流变换电路101的输出电流为第一预设电流的情况下直流汇流箱10的输出端电压，有效检测出直流汇流箱10输出端的阻性阻抗、容性阻抗、感性阻抗的大小情况。在已知单个直流汇流箱的输出阻抗值以及逆变器20的输入阻抗值的情况下，控制器103可以根据计算得到的直流汇流箱10的输出阻抗值，判断出直流汇流箱10输出端是否连接有其它直流汇流箱以及逆变器20，也可以判断出直流汇流箱10所处供电系统1的各个直流汇流箱以及各个逆变器20之间的连接关系。
举例来说，假设每个直流汇流箱的输出阻抗均为阻性并联容性，并且，阻值为1MΩ,容值为100μF；逆变器输入阻抗为感性串联容性，并且，感值为100μH，容值为500μF。控制器计算得到的直流汇流箱的输出阻抗值为0.2MΩ电阻并联500μF电容，再并联100μH电感与500μF电容的串联，则控制器可以判断出该直流汇流箱输出端连接有4个其他直流汇流箱，并且连接有逆变器；同时直流汇流箱之间为并联关系，各个直流汇流箱输出端并联后再与逆变器输入端并联。
在本申请实施例中，控制器103可以根据计算得到的直流汇流箱10的输出阻抗值确定直流汇流箱10与直流汇流箱11、…、直流汇流箱1n以及逆变器20的连接关系，并根据该连接关系控制直流变换电路101的输出电压，保证直流汇流箱10在与逆变器20难以通信的情况下依然可以正常启动和工作，提高了供电系统1的稳定性，适用性强。
基于图1b所示的供电系统1，本申请还提供了一种直流汇流箱的输出电压控制方法，包括：
控制器103控制直流变换电路101的输出电压为第一预设电压，并根据第一预设电压以及直流汇流箱10的输出端电流确定直流汇流箱10的输出阻抗值，在直流汇流箱10的输出阻抗值大于预设输出阻抗阈值的情况下，控制直流变换电路101的输出电压为第二预设电压，其中，直流汇流箱10的输出端电流由检测电路102在直流变换电路101的输出电压为第一预设电压的情况下检测得到。
或者，控制器103控制直流变换电路101的输出电流为第一预设电流，并根据第一预设电流以及直流汇流箱10的输出端电压确定直流汇流箱10的输出阻抗值，在直流汇流箱10的输出阻抗值大于预设输出阻抗阈值的情况下，控制直流变换电路101的输出电压为第二预设电压，其中，直流汇流箱10的输出端电压由检测电路102在直流变换电路101的输出电流为第一预设电流的情况下检测得到。
在另一可选实施例中，当直流汇流箱10输入端供电时，此时直流汇流箱10的输入电压或者输入电流不为0，控制器103开始工作，同时向检测电路102发送输出电压电流采样信号。检测电路102根据输出电压电流采样信号采集直流汇流箱10的输出端电压和输出端电流，并将直流汇流箱10的输出端电压和输出端电流返回至控制器103。
具体的，控制器103判断直流汇流箱10的输出端电压是否满足预设输出电压范围(即大于0并且小于或者等于第一预设电压)，在直流汇流箱10的输出端电压满足预设输出电压范围的情况下，说明直流汇流箱10与供电系统1中其他直流汇流箱相连，并且，与直流汇流箱10相连的其他直流汇流箱已经开始输出第一预设电压，直流汇流箱10无需再自行输出第一预设电压，则控制器103将直流汇流箱10的输出端电压与输出端电流之间的比值确定为直流汇流箱10的输出阻抗值，并在直流汇流箱10的输出阻抗值大于预设输出阻抗阈值的情况下，控制直流变换电路101的输出电压调整为第二预设电压。
可选的，控制器103判断直流汇流箱10的输出端电流是否满足预设输出电流范围(即大于0并且小于或者等于第一预设电流)，在直流汇流箱10的输出端电流满足预设输出电流范围的情况下，说明直流汇流箱10与供电系统1中其他直流汇流箱相连，并且，与直流汇流箱10相连的其他直流汇流箱已经开始输出第一预设电流，直流汇流箱10无需再自行输出第一预设电流，则控制器103将直流汇流箱10的输出端电压与输出端电流之间的比值确定为直流汇流箱10的输出阻抗值，并在直流汇流箱10的输出阻抗值大于预设输出阻抗阈值的情况下，控制直流变换电路101的输出电压调整为第二预设电压。
在本申请实施例中，控制器103在直流汇流箱10的输出端电压满足预设输出电压范围的情况下，无需再输出第一预设电压，或者，在直流汇流箱10的输出端电流满足预设输出电流范围的情况下，无需再输出第一预设电流。之后可直接根据直流汇流箱10的输出端电压和输出端电流确定直流汇流箱10与直流汇流箱11、…、直流汇流箱1n以及逆变器20的连接关系，并根据该连接关系控制直流变换电路101的输出电压，进而应对了已有其他直流汇流箱开始输出电压或者电流的情况，避免了直流汇流箱10再次输出电压或者电流而与已有其他直流汇流箱的输出电压或者电流产生冲突的问题，并保证直流汇流箱10在与逆变器20以及其他相连直流汇流箱难以通信的情况下依然可以正常启动和工作，提高了供电系统1的稳定性，适用性强。
基于图1b所示的供电系统1，本申请还提供了一种直流汇流箱的输出电压控制方法，包括：
在直流汇流箱10的输出端电压满足预设输出电压范围或者直流汇流箱10的输出端电流满足预设输出电流范围的情况下，根据直流汇流箱10的输出端电压和输出端电流确定直流汇流箱10的输出阻抗值，在直流汇流箱10的输出阻抗值大于预设输出阻抗阈值的情况下，控制直流变换电路101的输出电压为第二预设电压，其中，直流汇流箱10的输出端电压和输出端电流由检测电路102在直流汇流箱10的输入参数不为预设输入参数值的情况下检测得到。
在另一可选实施例中，当直流汇流箱10输入端供电时，此时直流汇流箱10的输入电压或者输入电流不为0，控制器103开始工作，同时向检测电路102发送输出残余电流采样信号。检测电路102根据输出残余电流采样信号采集直流汇流箱10的输出残余电流，并将直流汇流箱10的输出残余电流返回至控制器103。控制器103比较直流汇流箱10 的输出残余电流与预设残余电流阈值的大小，在直流汇流箱10的输出残余电流大于预设残余电流阈值(例如100mA)的情况下，确定直流汇流箱10与逆变器20相连，并控制直流变换电路101的输出电压为第二预设电压。示例性的，检测电路102为残余电流装置(Residual Current Device，RCD)。
在本申请实施例中，控制器103可以根据直流汇流箱10的输出残余电流确定直流汇流箱10与逆变器20的连接关系，并根据该连接关系控制直流变换电路101的输出电压，保证直流汇流箱10在与逆变器20难以通信的情况下依然可以正常启动和工作，提高了供电系统1的稳定性，适用性强。
基于图1b所示的供电系统1，本申请还提供了一种直流汇流箱的输出电压控制方法，包括：
控制器103在直流汇流箱10的输出残余电流大于预设残余电流阈值的情况下，控制直流变换电路101的输出电压为第二预设电压，其中，直流汇流箱10的输出残余电流由检测电路102在直流汇流箱10的输入参数不为预设输入参数值的情况下检测得到。
在又一可选实施例中，当直流汇流箱10输入端供电时，此时直流汇流箱10的输入电压或者输入电流不为0，控制器103开始工作，同时向检测电路102发送输出电压采样信号。检测电路102根据输出电压采样信号采集直流汇流箱10的输出端电压，并将直流汇流箱10的输出端电压返回至控制器103。
控制器103判断直流汇流箱10的输出端电压是否大于预设输出电压阈值，其中，预设输出电压阈值大于第一预设电压。在直流汇流箱10的输出端电压大于预设输出电压阈值的情况下，说明直流汇流箱10与供电系统1中其他直流汇流箱相连，并且，与直流汇流箱10相连的其他直流汇流箱已经开始启动，则控制器103控制直流变换电路101的输出电压调整为直流汇流箱10的输出端电压，即控制直流变换电路101的输出电压跟随直流汇流箱10的输出端电压。
在本申请实施例中，控制器103在直流汇流箱10的输出端电压大于预设输出电压阈值的情况下，可确定与直流汇流箱10相连的其他直流汇流箱已经开始启动，则控制直流变换电路101的输出电压跟随直流汇流箱10的输出端电压，进而避免了直流汇流箱10未启动时输出端电压已经过高带来的电流冲击问题，并保证直流汇流箱10在与逆变器20以及其他相连直流汇流箱难以通信的情况下依然可以正常启动和工作，提高了供电系统1的稳定性，适用性强。
基于图1b所示的供电系统1，本申请还提供了一种直流汇流箱的输出电压控制方法，包括：
直流汇流箱10的输出端参数包括直流汇流箱10的输出端电压；
控制器103在直流汇流箱10的输出端电压大于预设输出电压阈值的情况下，控制直流变换电路101的输出电压为直流汇流箱10的输出端电压，其中，直流汇流箱10的输出端电压由检测电路102在直流汇流箱10的输入参数不为预设输入参数值的情况下检测得到。
进一步地，图1b所示的供电系统1中的各个直流汇流箱还可以包括通信电路，具体请参见图3所示的供电系统的另一结构示意图。如图3所示，直流汇流箱10还包括通信电路104，用于接收逆变器20发送的指令，并将指令发送至控制器103。其中，通信电路104与逆变器20之间的通信方式可以为功率线缆通信，专用有线通信，或者无线通信。
在一可选实施例中，当直流汇流箱10输入端供电时，控制器103开始工作，同时控制直流变换电路101的输出电压为第一预设电压，并在直流变换电路101的输出电压为第一预设电压的情况下，向检测电路102发送输出电流采样信号。检测电路102根据输出电流采样信号采集直流汇流箱10的输出端电流，并将直流汇流箱10的输出端电流发送至控制器103。控制器103根据第一预设电压和直流汇流箱10的输出端电流确定直流汇流箱10的输出阻抗值，在直流汇流箱10的输出阻抗值大于预设输出阻抗阈值的情况下，控制直流变换电路101的输出电压从第一预设电压升高为第二预设电压。
可选的，当直流汇流箱10输入端供电时，控制器103开始工作，同时控制直流变换电路101的输出电流为第一预设电流，并在直流变换电路101的输出电流为第一预设电流的情况下，向检测电路102发送输出电压采样信号。检测电路102根据输出电压采样信号采集直流汇流箱10的输出端电压，并将直流汇流箱10的输出端电压发送至控制器103。控制器103根据第一预设电流和直流汇流箱10的输出端电压确定直流汇流箱10的输出阻抗值，在直流汇流箱10的输出阻抗值大于预设输出阻抗阈值的情况下，控制直流变换电路101输出电压从第一预设电压调整为第二预设电压。
可选的，当直流汇流箱10输入端供电时，此时直流汇流箱10的输入电压或者输入电流不为0，控制器103开始工作，同时向检测电路102发送输出电压电流采样信号。检测电路102根据输出电压电流采样信号采集直流汇流箱10的输出端电压和输出端电流，并将直流汇流箱10的输出端电压和输出端电流返回至控制器103。控制器103在直流汇流箱10的输出端电压满足预设输出电压范围或者直流汇流箱10的输出端电流满足预设输出电流范围的情况下，根据直流汇流箱10的输出端电压和输出端电流确定直流汇流箱10的输出阻抗值，在直流汇流箱10的输出阻抗值大于预设输出阻抗阈值的情况下，控制直流变换电路101的输出电压为第二预设电压。
可选的，当直流汇流箱10输入端供电时，此时直流汇流箱10的输入电压或者输入电流不为0，控制器103开始工作，同时向检测电路102发送输出残余电流采样信号。检测电路102根据输出残余电流采样信号采集直流汇流箱10的输出残余电流，并将直流汇流箱10的输出残余电流发送至控制器103。控制器103在直流汇流箱10的输出残余电流大于预设输出残余电流阈值的情况下，控制直流变换电路101的输出电压为第二预设电压。
直流变换电路101输出第二预设电压时，逆变器20输入端得到与之相等的电压，该电压设定在能够使逆变器20的辅助电源、控制单元以及通信单元开始工作的数值。之后，逆变器20向直流汇流箱10的通信电路104发送指令，通信电路104将该指令发送至控制器103，控制器103接收到该指令后，控制直流变换电路101的输出电压从第二预设电压调整为第三预设电压，从而使直流汇流箱10完成启动。其中，第三预设电压通常为直流变换电路101的额定电压，并且，大于或者等于第二预设电压。
在本申请实施例中，控制器103可根据直流汇流箱10的输出阻抗值或者输出残余电流确定直流汇流箱10与逆变器20的连接关系，并根据该连接关系控制直流变换电路101输出第二预设电压，保证直流汇流箱10在与逆变器20难以通信的情况下依然可以正常开始启动，提高了供电系统1的稳定性，适用性强。此外，在直流变换电路101的输出电压为第二预设电压时，控制器103不再控制直流变换电路101的输出电压继续升高，而是在接收到逆变器20发送的指令的情况下才继续控制直流变换电路101完成启动，可有效减少供电系统1的损耗，降低供电系统1误操作的几率。
基于图1b所示的供电系统1，本申请还提供了一种直流汇流箱的输出电压控制方法， 包括：
直流汇流箱10还包括通信电路104，通信电路104用于接收逆变器20发送的指令，并将指令发送至控制器103；
控制器103在确定直流汇流箱10与逆变器20相连的情况下，控制直流变换电路101的输出电压为第二预设电压，并在接收到指令的情况下，控制直流变换电路101的输出电压从第二预设电压调整为第三预设电压，其中，第三预设电压大于或者等于第二预设电压，并且，第三预设电压为直流变换电路101的额定电压。
在另一可选实施例中，当直流汇流箱10输入端供电时，控制器103开始工作，在控制器103通过通信电路104接收到逆变器20发送的指令的情况下，控制器103控制直流变换电路101的输出电压为第三预设电压，其中，第三预设电压为直流变换电路101的额定电压。
在本申请实施例中，逆变器20已由其他直流汇流箱提供电压，或者由电网等额外方式提供电压，并向直流汇流箱10的通信电路104发送指令。因此，控制器103接收到指令后，可以直接控制直流变换电路101的输出电压为第三预设电压，从而使直流汇流箱10完成启动。
参见图4，图4是本申请提供的直流汇流箱的输出端并联的供电系统的又一结构示意图。如图4所示，供电系统1包括第一组直流汇流箱11和第二组直流汇流箱21，第一逆变器30和第二逆变器32。其中，第一组直流汇流箱11包括直流汇流箱11-1、直流汇流箱11-2、…、直流汇流箱11-n，第二组直流汇流箱21包括直流汇流箱21-1、直流汇流箱21-2、…、直流汇流箱21-m。
直流汇流箱11-1、直流汇流箱11-2、…、以及直流汇流箱11-n的输出端并联，并且，直流汇流箱11-1、直流汇流箱11-2、…、以及直流汇流箱11-n的正输出端耦合，构成第一节点41，第一节点41通过第一导线与第一逆变器31的正输入端连接。直流汇流箱11-1、直流汇流箱11-2、…、以及直流汇流箱11-n的负输出端耦合，构成第二节点42。
直流汇流箱21-1、直流汇流箱21-2、…、直流汇流箱21-m的输出端并联，并且，直流汇流箱21-1、直流汇流箱21-2、…、以及直流汇流箱21-m的负输出端耦合，构成第三节点43，第三节点43通过第二导线与第二逆变器32的负输入端连接。
第一逆变器31的负输入端与第二逆变器32的正输入端耦合，构成第四节点44，第四节点44与第二节点42通过第三导线连接。其中，第一导线的通流能力和第二导线的通流能力均大于或者等于第三导线的通流能力。
由于第三导线上同时流过第一组直流汇流箱的输出电流和第二组直流汇流箱的输出电流，并且方向相反，存在抵消的现象，因此在正常的工作模式下，第三导线的电流值小于或等于第一导线或者第二导线的电流值，可以选取通流能力较低的导线，从而节省线缆，降低供电系统的成本。
当直流汇流箱输出端并联后分为多组时，不同组的直流汇流箱在维护模式下的输出电压(即第一预设电压)可以相同，也可以不同；不同组的直流汇流箱在维护模式下的输出电流(即第一预设电流)可以相同，也可以不同。
本申请实施例中，供电系统1中各个直流汇流箱的结构以及控制各个直流汇流箱的输出电压的具体实现方式请参见图1b和图3所示实施例中的直流汇流箱的结构以及控制各个直流汇流箱的输出电压的具体实现方式，此处不再赘述。
可以理解，本申请实施例可根据直流汇流箱的输出端参数，实现对直流汇流箱输出电压 的控制，保证直流汇流箱在与逆变器难以通信的情况下依然可以正常启动和工作，提高了供电系统1的稳定性，适用性强。此外，通过设置不同组的直流汇流箱在维护模式下的输出电压不同，可以在对直流汇流箱进行测试时，进一步判断出直流汇流箱是否连接至正确的分组，从而简化了供电系统1的检测方式，降低了供电系统1的维护成本。
参见图5，图5是本申请提供的直流汇流箱的输出端串联的供电系统的一结构示意图。如图5所示，供电系统1包括直流汇流箱10、直流汇流箱11、…、直流汇流箱1n以及逆变器20，其中，直流汇流箱10的输入端与直流电源1001、直流电源1002、…、直流电源100a相连，直流汇流箱11的输入端与直流电源1101、直流电源1102、…、直流电源110b相连，…，直流汇流箱1n的输入端与直流电源1n01、直流电源1n02、…、直流电源1n0x相连。直流汇流箱10的负输出端与直流汇流箱11的正输出端相连，…，直流汇流箱1(n-1)的负输出端与直流汇流箱1n的正输出端相连，直流汇流箱10的正输出端与逆变器20的正输入端相连，直流汇流箱1n的负输出端与逆变器20的负输出端相连，逆变器20的输出端连接交流电网。
由于供电系统1中每个直流汇流箱的结构以及其输出电压控制方式均相同，下面以直流汇流箱10为例进行说明。直流汇流箱10包括直流变换电路101、检测电路102和控制器103，其中，直流变换电路101的输入端与直流汇流箱10的输入端耦合，直流变换电路101的输出端经过检测电路102与直流汇流箱10的输出端耦合。
控制器103可根据直流汇流箱10的输出端参数，确定直流汇流箱10与供电系统1中其他直流汇流箱(对应直流汇流箱11、…、直流汇流箱1n)或者逆变器20的连接关系，并根据该连接关系控制直流变换电路101的输出电压。
在一可选实施例中，当直流汇流箱10输入端供电时，控制器103开始工作，同时控制直流变换电路101的输出电压为第一预设电压，其中，第一预设电压包括直流电压、交流电压或者直流电压叠加交流电压。第一预设电压可以为小于或者等于人体的安全电压，例如36V。之后，控制器103在直流变换电路101的输出电压为第一预设电压的情况下，向检测电路102发送输出电流采样信号。检测电路102根据输出电流采样信号采集直流汇流箱10的输出端电流，并将直流汇流箱10的输出端电流返回至控制器103。控制器103将第一预设电压与直流汇流箱10的输出端电流之间的比值确定为直流汇流箱10的输出阻抗值，并比较直流汇流箱10的输出阻抗值与预设输出阻抗阈值的大小，在直流汇流箱10的输出阻抗值大于预设输出阻抗阈值的情况下，确定直流汇流箱10与逆变器20相连，并控制直流变换电路101的输出电压从第一预设电压调整为第二预设电压，其中，第二预设电压大于第一预设电压。
在另一可选实施例中，当直流汇流箱10输入端供电时，控制器103开始工作，同时控制直流变换电路101的输出电流为第一预设电流，其中，第一预设电流包括直流电流、交流电流或者直流电流叠加交流电流。第一预设电流可以为小于或者等于人体的安全电流，或者，当直流变换电路101的输出电流为第一预设电流时，直流变换电路101的输入电压为小于或者等于人体的安全电压。之后，控制器103在直流变换电路101的输出电流为第一预设电流的情况下，向检测电路102发送输出电压采样信号。检测电路102根据输出电压采样信号采集直流汇流箱10的输出端电压，并将直流汇流箱10的输出端电压返回至控制器103。控制器103将直流汇流箱10的输出端电压与第一预设电流之间的比值确定为直流汇流箱10的输出阻抗值，并比较直流汇流箱10的输出阻抗值与预设输出阻抗阈值的大小，在直流汇流箱10的输出阻抗值大于预设输出阻抗阈值的情况下， 确定直流汇流箱10与逆变器20相连，并控制直流变换电路101的输出电压为第二预设电压。
需要说明的是，控制器103可以通过改变预设输出阻抗阈值大小的方式，进一步确定直流汇流箱10与直流汇流箱11、…、以及直流汇流箱1n的连接关系。此外，为了使逆变器20能够获得足够的电能并正常启动，控制器103通常是在确定直流汇流箱10与逆变器20相连，并且，与直流汇流箱10相连的其他直流汇流箱的数量大于预设数量阈值的情况下，控制直流变换电路101的输出电压为第二预设电压。
进一步地，控制器103可通过控制直流变换电路101输出直流电压叠加交流电压的第一预设电压，并且通过检测电路102检测得到直流变换电路101的输出电压为第一预设电压的情况下直流汇流箱10的输出端电流，有效检测出直流汇流箱10输出端的阻性阻抗、容性阻抗、感性阻抗的大小情况。控制器103也可通过控制直流变换电路101输出直流电流叠加交流电流的第一预设电流，并且通过检测电路102检测得到直流变换电路101的输出电流为第一预设电流的情况下直流汇流箱10的输出端电压，有效检测出直流汇流箱10输出端的阻性阻抗、容性阻抗、感性阻抗的大小情况。在已知单个直流汇流箱的输出阻抗值以及逆变器20的输入阻抗值的情况下，控制器103可以根据计算得到的直流汇流箱10的输出阻抗值，判断出直流汇流箱10输出端是否连接有其它直流汇流箱以及逆变器20，也可以判断出直流汇流箱10所处供电系统1的各个直流汇流箱以及各个逆变器20之间的连接关系。
在本申请实施例中，控制器103可以根据计算得到的直流汇流箱10的输出阻抗值确定直流汇流箱10与直流汇流箱11、…、直流汇流箱1n以及逆变器20的连接关系，并根据该连接关系控制直流变换电路101的输出电压，保证直流汇流箱10在与逆变器20难以通信的情况下依然可以正常启动和工作，提高了供电系统1的稳定性，适用性强。
基于图5所示的供电系统1，本申请还提供了一种直流汇流箱的输出电压控制方法，包括：
控制器103控制直流变换电路101的输出电压为第一预设电压，并根据第一预设电压以及直流汇流箱10的输出端电流确定直流汇流箱10的输出阻抗值，在直流汇流箱10的输出阻抗值大于预设输出阻抗阈值的情况下，控制直流变换电路101的输出电压为第二预设电压，其中，直流汇流箱10的输出端电流由检测电路102在直流变换电路101的输出电压为第一预设电压的情况下检测得到。
或者，控制器103控制直流变换电路101的输出电流为第一预设电流，并根据第一预设电流以及直流汇流箱10的输出端电压确定直流汇流箱10的输出阻抗值，在直流汇流箱10的输出阻抗值大于预设输出阻抗阈值的情况下，控制直流变换电路101的输出电压为第二预设电压，其中，直流汇流箱10的输出端电压由检测电路102在直流变换电路101的输出电流为第一预设电流的情况下检测得到。
在另一可选实施例中，当直流汇流箱10输入端供电时，此时直流汇流箱10的输入电压或者输入电流不为0，控制器103开始工作，同时向检测电路102发送输出电压电流采样信号。检测电路102根据输出电压电流采样信号采集直流汇流箱10的输出端电压和输出端电流，并将直流汇流箱10的输出端电压和输出端电流返回至控制器103。
具体的，控制器103判断直流汇流箱10的输出端电压是否满足预设输出电压范围(即大于0并且小于或者等于第一预设电压)，在直流汇流箱10的输出端电压满足预设输出 电压范围的情况下，说明直流汇流箱10与供电系统1中其他直流汇流箱相连，并且，与直流汇流箱10相连的其他直流汇流箱已经开始输出第一预设电压，直流汇流箱10无需再自行输出第一预设电压，则控制器103将直流汇流箱10的输出端电压与输出端电流之间的比值确定为直流汇流箱10的输出阻抗值，并在直流汇流箱10的输出阻抗值大于预设输出阻抗阈值的情况下，控制直流变换电路101的输出电压调整为第二预设电压。
可选的，控制器103判断直流汇流箱10的输出端电流是否满足预设输出电流范围(即大于0并且小于或者等于第一预设电流)，在直流汇流箱10的输出端电流满足预设输出电流范围的情况下，说明直流汇流箱10与供电系统1中其他直流汇流箱相连，并且，与直流汇流箱10相连的其他直流汇流箱已经开始输出第一预设电流，直流汇流箱10无需再自行输出第一预设电流，则控制器103将直流汇流箱10的输出端电压与输出端电流之间的比值确定为直流汇流箱10的输出阻抗值，并在直流汇流箱10的输出阻抗值大于预设输出阻抗阈值的情况下，控制直流变换电路101的输出电压调整为第二预设电压。
在本申请实施例中，控制器103在直流汇流箱10的输出端电压满足预设输出电压范围的情况下，无需再输出第一预设电压，或者，在直流汇流箱10的输出端电流满足预设输出电流范围的情况下，无需再输出第一预设电流。之后可直接根据直流汇流箱10的输出端电压和输出端电流确定直流汇流箱10与直流汇流箱11、…、直流汇流箱1n以及逆变器20的连接关系，并根据该连接关系控制直流变换电路101的输出电压，进而应对了已有其他直流汇流箱开始输出电压或者电流的情况，避免了直流汇流箱10再次输出电压或者电流而与已有其他直流汇流箱的输出电压或者电流产生冲突的问题，并保证直流汇流箱10在与逆变器20以及其他相连直流汇流箱难以通信的情况下依然可以正常启动和工作，提高了供电系统1的稳定性，适用性强。
基于图5所示的供电系统1，本申请还提供了一种直流汇流箱的输出电压控制方法，包括：
在直流汇流箱10的输出端电压满足预设输出电压范围或者直流汇流箱10的输出端电流满足预设输出电流范围的情况下，根据直流汇流箱10的输出端电压和输出端电流确定直流汇流箱10的输出阻抗值，在直流汇流箱10的输出阻抗值大于预设输出阻抗阈值的情况下，控制直流变换电路101的输出电压为第二预设电压，其中，直流汇流箱10的输出端电压和输出端电流由检测电路102在直流汇流箱10的输入参数不为预设输入参数值的情况下检测得到。
在另一可选实施例中，当直流汇流箱10输入端供电时，此时直流汇流箱10的输入电压或者输入电流不为0，控制器103开始工作，同时向检测电路102发送输出残余电流采样信号。检测电路102根据输出残余电流采样信号采集直流汇流箱10的输出残余电流，并将直流汇流箱10的输出残余电流返回至控制器103。控制器103比较直流汇流箱10的输出残余电流与预设残余电流阈值的大小，在直流汇流箱10的输出残余电流大于预设残余电流阈值的情况下，确定直流汇流箱10与逆变器20相连，并控制直流变换电路101的输出电压为第二预设电压。
在本申请实施例中，控制器103可以根据直流汇流箱10的输出残余电流确定直流汇流箱10与逆变器20的连接关系，并根据该连接关系控制直流变换电路101的输出电压，保证直流汇流箱10在与逆变器20难以通信的情况下依然可以正常启动和工作，提高了供电系统1的稳定性，适用性强。
基于图5所示的供电系统1，本申请还提供了一种直流汇流箱的输出电压控制方法，包括：
控制器103在直流汇流箱10的输出残余电流大于预设残余电流阈值的情况下，控制直流变换电路101的输出电压为第二预设电压，其中，直流汇流箱10的输出残余电流由检测电路102在直流汇流箱10的输入参数不为预设输入参数值的情况下检测得到。
在另一可选实施例中，当直流汇流箱10输入端供电时，此时直流汇流箱10的输入电压或者输入电流不为0，控制器103开始工作，同时向检测电路102发送输出电压采样信号。检测电路102根据输出电压采样信号采集直流汇流箱10的输出端电压，并将直流汇流箱10的输出端电压返回至控制器103。
控制器103判断直流汇流箱10的输出端电压是否大于预设输出电压阈值，其中，预设输出电压阈值大于第一预设电压。在直流汇流箱10的输出端电压大于预设输出电压阈值的情况下，说明直流汇流箱10与供电系统1中其他直流汇流箱相连，并且，与直流汇流箱10相连的其他直流汇流箱已经开始启动，则控制器103控制直流变换电路101的输出电压调整为直流汇流箱10的输出端电压，即控制直流变换电路101的输出电压跟随直流汇流箱10的输出端电压。
在本申请实施例中，控制器103在直流汇流箱10的输出端电压大于预设输出电压阈值的情况下，可确定与直流汇流箱10相连的其他直流汇流箱已经开始启动，则控制直流变换电路101的输出电压跟随直流汇流箱10的输出端电压，进而避免了直流汇流箱10未启动时输出端电压已经过高带来的电流冲击问题，并保证直流汇流箱10在与逆变器20以及其他相连直流汇流箱难以通信的情况下依然可以正常启动和工作，提高了供电系统1的稳定性，适用性强。
基于图5所示的供电系统1，本申请还提供了一种直流汇流箱的输出电压控制方法，包括：
直流汇流箱10的输出端参数包括直流汇流箱10的输出端电压；
控制器103在直流汇流箱10的输出端电压大于预设输出电压阈值的情况下，控制直流变换电路101的输出电压为直流汇流箱10的输出端电压，其中，直流汇流箱10的输出端电压由检测电路102在直流汇流箱10的输入参数不为预设输入参数值的情况下检测得到。
在又一可选实施例中，当直流汇流箱10输入端供电时，此时直流汇流箱10的输入电压或者输入电流不为0，控制器103开始工作，同时向检测电路102发送输出电流电压采样信号。检测电路102根据输出电流电压采样信号采集直流汇流箱10的输出端电流和输出端电压，并将直流汇流箱10的输出端电流和输出端电压返回至控制器103。
控制器103判断直流汇流箱10的输出端电流是否大于预设输出电流阈值，其中，预设输出电流阈值大于第一预设电流。在直流汇流箱10的输出端电流大于预设输出电流阈值的情况下，说明直流汇流箱10与供电系统1中其他直流汇流箱相连，并且，与直流汇流箱10相连的其他直流汇流箱已经开始启动，则控制器103控制直流变换电路101的输出电压调整为直流汇流箱10的输出端电压，即控制直流变换电路101的输出电压跟随直流汇流箱10的输出端电压。
在本申请实施例中，控制器103在直流汇流箱10的输出端电流大于预设输出电流阈值 的情况下，可确定与直流汇流箱10相连的其他直流汇流箱已经开始启动，则控制直流变换电路101的输出电压跟随直流汇流箱10的输出端电压，进而避免了直流汇流箱10未启动时输出端电流已经过高带来的电流冲击问题，并保证直流汇流箱10在与逆变器20及其他相连直流汇流箱难以通信的情况下依然可以正常启动和工作，提高了供电系统1的稳定性，适用性强。
基于图5所示的供电系统1，本申请还提供了一种直流汇流箱的输出电压控制方法，包括：
直流汇流箱10的输出端参数包括直流汇流箱10的输出端电流和输出端电压；
控制器103在直流汇流箱10的输出端电流大于预设输出电流阈值的情况下，控制直流变换电路101的输出电压为直流汇流箱10的输出端电压，其中，直流汇流箱10的输出端电流和输出端电压由检测电路102在直流汇流箱10的输入参数不为预设输入参数值的情况下检测得到。
进一步地，图5所示的供电系统1中的各个直流汇流箱还可以包括通信电路，具体请参见图6所示的供电系统的另一结构示意图。如图6所示，直流汇流箱10还包括通信电路104，用于接收逆变器20发送的指令，并将指令发送至控制器103。其中，通信电路104与逆变器20之间的通信方式可以为功率线缆通信，专用有线通信，或者无线通信。
在一可选实施例中，当直流汇流箱10输入端供电时，控制器103开始工作，同时控制直流变换电路101的输出电压为第一预设电压，并在直流变换电路101的输出电压为第一预设电压的情况下，向检测电路102发送输出电流采样信号。检测电路102根据输出电流采样信号采集直流汇流箱10的输出端电流，并将直流汇流箱10的输出端电流发送至控制器103。控制器103根据第一预设电压和直流汇流箱10的输出端电流确定直流汇流箱10的输出阻抗值，在直流汇流箱10的输出阻抗值大于预设输出阻抗阈值的情况下，控制直流变换电路101的输出电压从第一预设电压升高为第二预设电压。
可选的，当直流汇流箱10输入端供电时，控制器103开始工作，同时控制直流变换电路101的输出电流为第一预设电流，并在直流变换电路101的输出电流为第一预设电流的情况下，向检测电路102发送输出电压采样信号。检测电路102根据输出电压采样信号采集直流汇流箱10的输出端电压，并将直流汇流箱10的输出端电压发送至控制器103。控制器103根据第一预设电流和直流汇流箱10的输出端电压确定直流汇流箱10的输出阻抗值，在直流汇流箱10的输出阻抗值大于预设输出阻抗阈值的情况下，控制直流变换电路101输出电压从第一预设电压调整为第二预设电压。
可选的，当直流汇流箱10输入端供电时，此时直流汇流箱10的输入电压或者输入电流不为0，控制器103开始工作，同时向检测电路102发送输出电压电流采样信号。检测电路102根据输出电压电流采样信号采集直流汇流箱10的输出端电压和输出端电流，并将直流汇流箱10的输出端电压和输出端电流返回至控制器103。控制器103在直流汇流箱10的输出端电压满足预设输出电压范围或者直流汇流箱10的输出端电流满足预设输出电流范围的情况下，根据直流汇流箱10的输出端电压和输出端电流确定直流汇流箱10的输出阻抗值，在直流汇流箱10的输出阻抗值大于预设输出阻抗阈值的情况下，控制直流变换电路101的输出电压为第二预设电压。
可选的，当直流汇流箱10输入端供电时，此时直流汇流箱10的输入电压或者输入电流不为0，控制器103开始工作，同时向检测电路102发送输出残余电流采样信号。检测电 路102根据输出残余电流采样信号采集直流汇流箱10的输出残余电流，并将直流汇流箱10的输出残余电流发送至控制器103。控制器103在直流汇流箱10的输出残余电流大于预设输出残余电流阈值的情况下，控制直流变换电路101的输出电压为第二预设电压。
直流变换电路101输出第二预设电压时，逆变器20输入端得到与之相等的电压，该电压设定在能够使逆变器20的辅助电源、控制单元以及通信单元开始工作的数值。之后，逆变器20向直流汇流箱10的通信电路104发送指令，通信电路104将该指令发送至控制器103，控制器103接收到该指令后，控制直流变换电路101的输出电压从第二预设电压上升至第三预设电压，从而使直流汇流箱10完成启动。其中，第三预设电压通常为直流变换电路101的额定电压，并且，大于或者等于第二预设电压。
在本申请实施例中，控制器103可根据直流汇流箱10的输出阻抗值或者输出残余电流确定直流汇流箱10与逆变器20的连接关系，并根据该连接关系控制直流变换电路101输出第二预设电压，保证直流汇流箱10在与逆变器20难以通信的情况下依然可以正常开始启动，提高了供电系统1的稳定性，适用性强。此外，在直流变换电路101的输出电压为第二预设电压时，控制器103不再控制直流变换电路101的输出电压继续升高，而是在接收到逆变器20发送的工作指令的情况下才继续控制直流变换电路101完成启动，可有效减少供电系统1的损耗，降低供电系统1误操作的几率。
基于图5所示的供电系统1，本申请还提供了一种直流汇流箱的输出电压控制方法，包括：
直流汇流箱10还包括通信电路104，通信电路104用于接收逆变器20发送的指令，并将指令发送至控制器103；
控制器103在确定直流汇流箱10与逆变器20相连的情况下，控制直流变换电路101的输出电压为第二预设电压，并在接收到指令的情况下，控制直流变换电路101的输出电压从第二预设电压调整为第三预设电压，其中，第三预设电压大于或者等于第二预设电压，并且，第三预设电压为直流变换电路101的额定电压。
在另一可选实施例中，当直流汇流箱10输入端供电时，控制器103开始工作，在控制器103通过通信电路104接收到逆变器20发送的指令的情况下，控制器103控制直流变换电路101的输出电压为第三预设电压，其中，第三预设电压为直流变换电路101的额定电压。
在本申请实施例中，逆变器20已由其他直流汇流箱提供电压，或者由电网等额外方式提供电压，并向直流汇流箱10的通信电路104发送指令。因此，控制器103接收到指令后，可以直接控制直流变换电路101的输出电压为第三预设电压，从而使直流汇流箱10完成启动。
参见图7，图7是本申请提供的直流汇流箱的输出端串并联组合的供电系统的结构示意图。如图7所示，供电系统1包括第一组直流汇流箱11、第二组直流汇流箱21和逆变器31。其中，第一组直流汇流箱11包括直流汇流箱11-1、…、直流汇流箱11-n，第二组直流汇流箱21包括直流汇流箱21-1、…、直流汇流箱21-m。直流汇流箱11-1的负输出端与直流汇流箱11-2的正输出端串联，…，直流汇流箱11-(n-1)的负输出端与直流汇流箱11-n的正输出端串联，并且，直流汇流箱11-1的正输出端与逆变器31的正输入端相连，直流汇流箱11-n的负输出端与逆变器31的负输入端相连。直流汇流箱21-1、…、以及直流汇流箱21-m的正输出端并联后与逆变器31的正输入端相连，直流汇流箱21-1、…、以及直流汇流箱21-m的负输出端并联后与逆变器31的负输入端相连。
本申请实施例中，第一组直流汇流箱11中各个直流汇流箱的结构以及控制各个直流汇流箱的输出电压的具体实现方式请参见图5和图6所示实施例中的直流汇流箱的结构以及控制各个直流汇流箱的输出电压的具体实现方式，第二组直流汇流箱21中各个直流汇流箱的结构以及控制各个直流汇流箱的输出电压的具体实现方式请参见图1b和图3所示实施例中的直流汇流箱的结构以及控制各个直流汇流箱的输出电压的具体实现方式，此处不再赘述。
可以理解，本申请实施例可根据直流汇流箱的输出端参数，实现对直流汇流箱输出电压的控制，保证直流汇流箱在与逆变器难以通信的情况下依然可以正常启动和工作，提高了供电系统1的稳定性，适用性强。
需要说明的是，对于图1b-图7所示供电系统中的任一直流汇流箱而言，当直流汇流箱首次启动完成后，该直流汇流箱中的控制器可将该直流汇流箱输出端连接其他直流汇流箱或逆变器的情况记录起来。在通常情况下，直流汇流箱之间，以及与逆变器之间的连接关系在供电系统安装完毕后是不会改变的。因此，在任一直流汇流箱第二次启动以及此后启动时，该直流汇流箱中的控制器可以根据记录的输出端连接情况，使该直流汇流箱完成启动。当供电系统出现故障或者进行维护后，供电系统需要重置，则供电系统中的任一直流汇流箱中的控制器均可根据该直流汇流箱的首次启动方式(即图1b-图7所示实施例中直流汇流箱的启动方式)进行启动。
在本申请中，控制器根据直流汇流箱的输出端参数，确定该直流汇流箱与供电系统中其他直流汇流箱或者逆变器的连接关系，进而可根据该连接关系控制直流变换电路的输出电压，保证直流汇流箱在与逆变器难以通信的情况下依然可以正常启动和工作，提高了供电系统的稳定性，适用性强。
以上，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (30)

  1. 一种供电系统，其特征在于，所述供电系统包括至少一个直流汇流箱和逆变器，所述至少一个直流汇流箱中各个直流汇流箱的输出端串联和/或并联后与所述逆变器的输入端耦合，所述各个直流汇流箱的输入端与直流电源相连，所述直流汇流箱包括控制器、检测电路和直流变换电路，其中：
    所述直流变换电路的输入端与所述直流汇流箱的输入端耦合，所述直流变换电路的输出端与所述直流汇流箱的输出端耦合，所述直流变换电路用于将所述直流汇流箱的输入端电压直流变换为所述直流汇流箱的输出端电压；
    所述检测电路，用于检测所述直流汇流箱的输出端参数，并将所述直流汇流箱的输出端参数发送至所述控制器；
    所述控制器，用于根据所述直流汇流箱的输出端参数，控制所述直流变换电路的输出电压。
  2. 根据权利要求1所述的供电系统，其特征在于，所述检测电路用于在所述直流变换电路的输出电压为第一预设电压的情况下，检测得到所述直流汇流箱的输出端电流；
    所述控制器还用于控制所述直流变换电路的输出电压为所述第一预设电压；
    所述控制器用于根据所述第一预设电压以及所述直流汇流箱的输出端电流，确定所述直流汇流箱的输出阻抗值，在所述直流汇流箱的输出阻抗值大于预设输出阻抗阈值的情况下，控制所述直流变换电路的输出电压为第二预设电压，其中，所述第二预设电压大于第一预设电压。
  3. 根据权利要求2所述的供电系统，其特征在于，所述第一预设电压包括直流电压和/或交流电压。
  4. 根据权利要求1所述的供电系统，其特征在于，所述检测电路用于在所述直流变换电路的输出电流为第一预设电流的情况下，检测得到所述直流汇流箱的输出端电压；
    所述控制器还用于控制所述直流变换电路的输出电流为所述第一预设电流；
    所述控制器用于根据所述第一预设电流以及所述直流汇流箱的输出端电压，确定所述直流汇流箱的输出阻抗值，在所述直流汇流箱的输出阻抗值大于预设输出阻抗阈值的情况下，控制所述直流变换电路的输出电压为第二预设电压。
  5. 根据权利要求4所述的供电系统，其特征在于，所述第一预设电流包括直流电流和/或交流电流。
  6. 根据权利要求1所述的供电系统，其特征在于，所述检测电路用于在所述直流汇流箱的输入参数不为预设输入参数值的情况下，检测得到所述直流汇流箱的输出端电压和输出端电流；
    所述控制器用于在所述直流汇流箱的输出端电压满足预设输出电压范围或者所述直流汇流箱的输出端电流满足预设输出电流范围的情况下，根据所述直流汇流箱的输出端电压和所述输出端电流确定所述直流汇流箱的输出阻抗值，在所述直流汇流箱的输出阻抗值大于预设输出阻抗阈值的情况下，控制所述直流变换电路的输出电压为第二预设电 压。
  7. 根据权利要求6所述的供电系统，其特征在于，所述直流汇流箱的输出端电压包括直流电压和/或交流电压，所述直流汇流箱的输出端电流包括直流电流和/或交流电流。
  8. 根据权利要求1所述的供电系统，其特征在于，所述检测电路用于在所述直流汇流箱的输入参数不为预设输入参数值的情况下，检测所述直流汇流箱的输出残余电流；
    所述控制器用于在所述直流汇流箱的输出残余电流大于预设残余电流阈值的情况下，控制所述直流变换电路的输出电压为第二预设电压。
  9. 根据权利要求2-8任一项所述的供电系统，其特征在于，所述直流汇流箱还包括通信电路，所述通信电路用于接收所述逆变器发送的指令，并将所述指令发送至所述控制器；
    所述控制器还用于在接收到所述指令的情况下，控制所述直流变换电路的输出电压为第三预设电压，其中，所述第三预设电压大于或者等于所述第二预设电压，并且，所述第三预设电压为所述直流变换电路的额定电压。
  10. 根据权利要求2所述的供电系统，其特征在于，所述直流变换电路包括功率变换电路、电压调节电路和分断开关，所述功率变换电路的输出电压大于所述电压调节电路的输出电压，其中，所述功率变换电路的输入端通过所述分断开关与所述直流变换电路的输入端耦合，所述功率变换电路的输出端与所述直流变换电路的输出端耦合；所述电压调节电路的输入端与所述直流变换电路的输入端耦合，所述电压调节电路的输出端与所述直流变换电路的输出端耦合；
    所述控制器用于控制所述分断开关断开，并且，控制所述电压调节电路的输出电压为所述第一预设电压。
  11. 根据权利要求1所述的供电系统，其特征在于，所述检测电路用于在所述直流汇流箱的输入参数不为预设输入参数值的情况下，检测所述直流汇流箱的输出端电压；
    所述控制器用于在所述直流汇流箱的输出端电压大于预设输出电压阈值的情况下，控制所述直流变换电路的输出电压为所述直流汇流箱的输出端电压。
  12. 根据权利要求1所述的供电系统，其特征在于，所述检测电路用于在所述直流汇流箱的输入参数不为预设输入参数值的情况下，检测所述直流汇流箱的输出端电流和输出端电压；
    所述控制器用于在所述直流汇流箱的输出端电流大于预设输出电流阈值的情况下，控制所述直流变换电路的输出电压为所述直流汇流箱的输出端电压。
  13. 根据权利要求1-12任一项所述的供电系统，其特征在于，所述逆变器包括第一逆变器和第二逆变器，所述至少一个直流汇流箱包括第一组直流汇流箱和第二组直流汇流箱，所述第一组直流汇流箱和所述第二组直流汇流箱均包括至少一个直流汇流箱，其中：
    所述第一组直流汇流箱中各个直流汇流箱的输出端并联，所述第二组直流汇流箱中各个直流汇流箱的输出端并联；
    所述第一组直流汇流箱中各个直流汇流箱的第一输出端耦合，构成第一节点；
    所述第一节点与所述第一逆变器的第一输入端通过第一导线连接；
    所述第一组直流汇流箱中各个直流汇流箱的第二输出端与所述第二组直流汇流箱中各个直流汇流箱的第一输出端耦合，构成第二节点；
    所述第二组直流汇流箱中各个直流汇流箱的第二输出端耦合，构成第三节点；
    所述第三节点与所述第二逆变器的第二输入端通过第二导线连接；
    所述第一逆变器的第二输入端与所述第二逆变器的第一输入端耦合，构成第四节点；
    所述第四节点与所述第二节点通过第三导线连接，其中，所述第一导线的通流能力和所述第二导线的通流能力均大于或者等于所述第三导线的通流能力。
  14. 根据权利要求13所述的供电系统，其特征在于，所述第一组直流汇流箱在维护模式下的输出电压与所述第二组直流汇流箱在维护模式下的输出电压不同，并且，所述第一组直流汇流箱中各个直流汇流箱在维护模式下的输出电压相同，所述第二组直流汇流箱中各个直流汇流箱在维护模式下的输出电压相同。
  15. 根据权利要求1-14任一项所述的供电系统，其特征在于，所述直流电源包括光伏组串。
  16. 一种直流汇流箱的输出电压控制方法，其特征在于，所述方法适用于供电系统，所述供电系统包括至少一个直流汇流箱和逆变器，所述至少一个直流汇流箱中各个直流汇流箱的输出端串联和/或并联后与所述逆变器的输入端耦合，所述各个直流汇流箱的输入端与直流电源相连，所述直流汇流箱包括控制器、检测电路和直流变换电路，其中，所述直流变换电路的输入端与所述直流汇流箱的输入端耦合，所述直流变换电路的输出端与所述直流汇流箱的输出端耦合；
    所述方法包括：
    所述直流变换电路将所述直流汇流箱的输入端电压直流变换为所述直流汇流箱的输出端电压；
    所述检测电路检测所述直流汇流箱的输出参数，并将所述直流汇流箱的输出参数发送至所述控制器；
    所述控制器根据所述直流汇流箱的输出端参数，控制所述直流变换电路的输出电压。
  17. 根据权利要求16所述的方法，其特征在于，所述根据所述直流汇流箱的输出参数，控制所述直流变换电路的输出电压之前，还包括：
    控制所述直流变换电路的输出电压为第一预设电压；
    所述根据所述直流汇流箱的输出端参数，控制所述直流变换电路的输出电压，包括：
    根据所述第一预设电压以及所述直流汇流箱的输出端电流，确定所述直流汇流箱的输出阻抗值，在所述直流汇流箱的输出阻抗值大于预设输出阻抗阈值的情况下，控制所述直流变换电路的输出电压为第二预设电压，其中，所述第二预设电压大于所述第一预设电压，所述输出端电流由所述检测电路在所述直流变换电路的输出电压为所述第一预 设电压的情况下检测得到。
  18. 根据权利要求17所述的方法，其特征在于，所述第一预设电压包括直流电压和/或交流电压。
  19. 根据权利要求16所述的方法，其特征在于，所述根据所述直流汇流箱的输出参数，控制所述直流变换电路的输出电压之前，还包括：
    控制所述直流变换电路的输出电压为第一预设电流；
    所述根据所述直流汇流箱的输出端参数，控制所述直流变换电路的输出电压，包括：
    根据所述第一预设电流以及所述直流汇流箱的输出端电压，确定所述直流汇流箱的输出阻抗值，在所述直流汇流箱的输出阻抗值大于预设输出阻抗阈值的情况下，控制所述直流变换电路的输出电压为第二预设电压，其中，所述输出端电压由所述检测电路在所述直流变换电路的输出电流为所述第一预设电流的情况下检测得到。
  20. 根据权利要求19所述的方法，其特征在于，所述第一预设电流包括直流电流和/或交流电流。
  21. 根据权利要求16所述的方法，其特征在于，所述根据所述直流汇流箱的输出端参数，控制所述直流变换电路的输出电压，包括：
    在所述直流汇流箱的输出端电压满足预设输出电压范围或者所述直流汇流箱的输出端电流满足预设输出电流范围的情况下，根据所述直流汇流箱的输出端电压和所述输出端电流确定所述直流汇流箱的输出阻抗值，在所述直流汇流箱的输出阻抗值大于预设输出阻抗阈值的情况下，控制所述直流变换电路的输出电压为第二预设电压，其中，所述直流汇流箱的输出端电压和输出端电流由所述检测电路在所述直流汇流箱的输入参数不为预设输入参数值的情况下检测得到。
  22. 根据权利要求21所述的方法，其特征在于，所述直流汇流箱的输出端电压包括直流电压和/或交流电压，所述直流汇流箱的输出端电流包括直流电流和/或交流电流。
  23. 根据权利要求16所述的方法，其特征在于，所述根据所述直流汇流箱的输出端参数，控制所述直流变换电路的输出电压，包括：
    在所述直流汇流箱的输出残余电流大于预设残余电流阈值的情况下，控制所述直流变换电路的输出电压为第二预设电压，所述输出残余电流由所述检测电路在所述直流汇流箱的输入参数不为预设输入参数值的情况下检测得到。
  24. 根据权利要求17-23任一项所述的方法，其特征在于，所述直流汇流箱还包括通信电路，所述通信电路用于接收所述逆变器发送的指令，并将所述指令发送至所述控制器；
    所述控制所述直流变换电路的输出电压为第二预设电压之后，包括：
    在接收到所述指令的情况下，控制所述直流变换电路的输出电压为第三预设电压，其中，所述第三预设电压大于或者等于所述第二预设电压，并且，所述第三预设电压为 所述直流变换电路的额定电压。
  25. 根据权利要求17所述的方法，其特征在于，所述直流变换电路包括功率变换电路、电压调节电路和分断开关，所述功率变换电路的输出电压大于所述电压调节电路的输出电压，其中，所述功率变换电路的输入端通过所述分断开关与所述直流变换电路的输入端耦合，所述功率变换电路的输出端与所述直流变换电路的输出端耦合；所述电压调节电路的输入端与所述直流变换电路的输入端耦合，所述电压调节电路的输出端与所述直流变换电路的输出端耦合；
    所述控制所述直流变换电路的输出电压为第一预设电压，包括:
    控制所述分断开关断开，并且，控制所述电压调节电路的输出电压为所述第一预设电压。
  26. 根据权利要求16所述的方法，其特征在于，所述直流汇流箱的输出端参数包括所述直流汇流箱的输出端电压；
    根据所述直流汇流箱的输出端参数，控制所述直流变换电路的输出电压，包括：
    在所述直流汇流箱的输出端电压大于预设输出电压阈值的情况下，控制所述直流变换电路的输出电压为所述直流汇流箱的输出端电压，所述输出端电压由所述检测电路在所述直流汇流箱的输入参数不为预设输入参数值的情况下检测得到。
  27. 根据权利要求16所述的方法，其特征在于，所述直流汇流箱的输出端参数包括所述直流汇流箱的输出端电流和输出端电压；
    根据所述直流汇流箱的输出端参数，控制所述直流变换电路的输出电压，包括：
    在所述直流汇流箱的输出端电流大于预设输出电流阈值的情况下，控制所述直流变换电路的输出电压为所述直流汇流箱的输出端电压，所述输出端电流和所述输出端电压由所述检测电路在所述直流汇流箱的输入参数不为预设输入参数值的情况下检测得到。
  28. 根据权利要求16-27任一项所述的方法，其特征在于，所述逆变器包括第一逆变器和第二逆变器，所述至少一个直流汇流箱包括第一组直流汇流箱和第二组直流汇流箱，所述第一组直流汇流箱和所述第二组直流汇流箱均包括至少一个直流汇流箱，其中：
    所述第一组直流汇流箱中各个直流汇流箱的输出端并联，所述第二组直流汇流箱中各个直流汇流箱的输出端并联；
    所述第一组直流汇流箱中各个直流汇流箱的第一输出端耦合，构成第一节点；
    所述第一节点与所述第一逆变器的第一输入端通过第一导线连接；
    所述第一组直流汇流箱中各个直流汇流箱的第二输出端与所述第二组直流汇流箱中各个直流汇流箱的第一输出端耦合，构成第二节点；
    所述第二组直流汇流箱中各个直流汇流箱的第二输出端耦合，构成第三节点；
    所述第三节点与所述第二逆变器的第二输入端通过第二导线连接；
    所述第一逆变器的第二输入端与所述第二逆变器的第一输入端耦合，构成第四节点；
    所述第四节点与所述第二节点通过第三导线连接，其中，所述第一导线的通流能力和所述第二导线的通流能力均大于或者等于所述第三导线的通流能力。
  29. 根据权利要求28所述的方法，其特征在于，所述第一组直流汇流箱在维护模式下的输出电压与所述第二组直流汇流箱在维护模式下的输出电压不同，并且，所述第一组直流汇流箱中各个直流汇流箱在维护模式下的输出电压相同，所述第二组直流汇流箱中各个直流汇流箱在维护模式下的输出电压相同。
  30. 根据权利要求16-29所述的方法，其特征在于，所述直流电源包括光伏组串。
PCT/CN2022/082084 2021-03-30 2022-03-21 供电系统及直流汇流箱的输出电压控制方法 WO2022206461A1 (zh)

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