TWI712241B - Power conversion system and method of operating the same - Google Patents

Abstract

A power conversion system includes a UPS and a control unit, and the UPS includes a conversion module, a generator module and a DC-AC conversion unit. The control unit controls the generator module and the conversion module according to a power command to slowly increase or decrease a first average power provided by a DC power source coupled to the conversion module. The control unit controls the conversion module according to the bus voltage, so that a second average power provided by a mains power coupled to the conversion module slowly decreases or increases corresponding to the first average power.

Description

Power conversion system and its operation method

The invention relates to a power conversion system and an operation method thereof, in particular to a power conversion system and an operation method of a flexible load proportional transfer.

As the demand for servers or large data centers is increasing, and more reliable, faster deployment, and higher power density energy sources are needed to maintain the stability of the server or large data centers. Therefore, the demand for power conversion systems (Power Train Unit; PTU) has been paid more and more attention.

The traditional power conversion system usually has a monitoring system inside, integrating all the equipment of the power system in a single cabinet, which includes the power distribution system, air conditioning, automatic transfer switch (ATS), uninterruptible power system (UPS), battery, wiring, communication monitoring Wait. Because it is equipped with an uninterruptible power system, the power conversion system is highly reliable.

The traditional power conversion system selectively connects the mains or the generator as AC input through the automatic switch. When the mains is interrupted, the automatic switch is directly switched to the generator to supply power, which will cause the generator to instantaneously draw load and generate inrush current. The generation of inrush current can easily cause the generator to malfunction and shut down. Therefore, the generator capacity is designed to be at least 1.7 times the load capacity, but this has caused a substantial increase in equipment costs. And the generator is an important input source after the mains is interrupted, and it needs regular maintenance to ensure the reliability of the system. Due to the design of the automatic transfer switch, offline testing is generally selected, and a generator test load (Load Bank) must be added. Therefore, the cost of the generator test load must be increased, and when the generator test load is coupled to the generator, Wiring time.

Moreover, if the function test of the generator is performed, the load is switched at one time, and the inrush current can easily cause the generator to fail and must be switched back to the mains power supply immediately. Due to the slow switching speed of the automatic switch, the battery may be discharged during the switching process. And reduce the battery backup time. And, during the peak period of power consumption, the uninterruptible power system with automatic switch cannot transfer part of the load to the generator for power supply. In addition, the risk of a single point failure of the automatic transfer switch is high. If the automatic transfer switch fails, the uninterrupted power system will lose the input power, which will cause the output of the uninterrupted power system to be interrupted.

Therefore, how to design a power conversion system that does not need to install an automatic switch, and has the function of flexibly shifting the load ratio, is a major issue that the creator of this case wants to overcome and solve.

In order to solve the above-mentioned problems, the present invention provides a power conversion system to overcome the problems of the prior art. Therefore, the power conversion system of the present invention supplies power to the load, and the power conversion system includes: an uninterruptible power device, including: a conversion module, which is coupled to the mains power and the DC power source to convert the mains power and the DC power source into a bus voltage. And the DC-AC conversion unit is coupled to the conversion module and converts the bus voltage to supply power to the load. The generator module is coupled to the DC power supply. And a control unit, coupled to the conversion module. Wherein, the control unit controls the conversion module according to the power command to gradually increase or decrease the first average power provided by the DC power supply; the control unit controls the conversion module according to the bus voltage so that the second average power provided by the mains corresponds to the first average power The power is slowly reduced or increased.

In order to solve the above-mentioned problems, the present invention provides an operation method of a power conversion system to overcome the problems of the conventional technology. Therefore, the operating method of the power conversion system of the present invention includes: controlling the conversion module to convert the mains power and the DC power to the bus voltage. Control the DC-AC conversion unit to convert the bus voltage to supply power to the load. Control the generator module to provide electrical energy to the DC power supply. The first average power provided by the DC power supply is controlled to increase or decrease gradually according to the power command. And according to the bus voltage, the second average power provided by the mains is controlled to gradually decrease or increase corresponding to the first average power.

In order to further understand the technology, means and effects of the present invention to achieve the intended purpose, please refer to the following detailed description and drawings of the present invention. I believe that the purpose, features and characteristics of the present invention can be obtained from this in depth and For specific understanding, however, the accompanying drawings are only provided for reference and illustration, and are not intended to limit the present invention.

100: Power Conversion System

10: Uninterruptible power device

102, 102’: Conversion module

102-1: DC-DC conversion unit

102-2: AC-DC conversion unit

1022: First switching bridge arm

1024: second switching bridge arm

Q1~Q4: The first switch ~ the fourth switch

1026: The first booster unit

L1: first inductance

S1: The first power switch

D1: The first diode

C1: first capacitor

1028: Second booster unit

L2: second inductor

S2: second power switch

D2: The second diode

C2: second capacitor

104: DC-AC conversion unit

20: control unit

30: DC power supply module

302: Generator Module

302-1: Generator

302-2: AC-DC converter

304: Renewable Energy Module

304-1: Renewable energy unit

304-2: DC-DC converter

306: Energy Storage Module

200: load

Vac: mains

Vdc: DC power supply

Vo: output power

Vdc1: the first DC source

Vdc2: second DC source

Vbus: bus voltage

Vbus1: the first bus voltage

Vbus2: second bus voltage

Vp: predetermined output voltage

Vp1: The first predetermined output voltage

Vp2: second predetermined output voltage

V1~V3: first power supply~third power supply

A: Scheduled power supply

B: Redundant power

I1~I4: the first current ~ the fourth current

Ii: input current

Ii1: first input current

Ii2: second input current

Cp: power command

Pc: power value

Pc1: the first power value

Pc2: second power value

Cit1: The first total current command

Cit2: Second total current command

Ci1~Ci4: The first current command ~ the fourth current command

T1: During peak electricity consumption

T2: Use ionization peak period

DC_I_mod: current mode

AC_V_mod: voltage mode

N: node

Gpc, Gvc, Gic, Gic_dc, Gic_ac: control parameters

1 is a schematic diagram of a circuit block diagram of the power conversion system of the present invention; FIG. 2A is a schematic diagram of power transmission of the first embodiment of the power conversion system of the present invention; FIG. 2B is a schematic diagram of power transmission of the second embodiment of the power conversion system of the present invention; 2C is a schematic diagram of power transmission of the third embodiment of the power conversion system of the present invention; FIG. 3A is a schematic diagram of power consumption of the first embodiment of the power conversion system of the present invention; FIG. 3B is a schematic diagram of the second embodiment of the power conversion system of the present invention Power consumption diagram; Figure 4A is a circuit block diagram of the first embodiment of the conversion module of the present invention; Figure 4B is a control block diagram of the first embodiment of the conversion module of the present invention; Figure 5 is the second embodiment of the conversion module of the present invention Example circuit block diagram; and FIG. 6 is a control block diagram of the second embodiment of the conversion module of the present invention.

The technical content and detailed description of the present invention are described as follows in conjunction with the drawings: Please refer to FIG. 1 for a block diagram of the circuit of the power conversion system of the present invention. The power conversion system 100 receives the city power Vac and the DC power source Vdc, and converts the city power Vac and the DC power source Vdc into an output power source Vo to supply power to the load 200. The power conversion system 100 includes an uninterruptible power device 10 and a control unit 20. The uninterruptible power device 10 receives the commercial power Vac and the DC power Vdc, and is coupled to the load 200. The control unit 20 is coupled to the uninterruptible power device 10, and controls the uninterruptible power device 10 to convert the commercial power Vac or the direct current power Vdc into the output power Vo. The uninterruptible power device 10 includes a conversion module 102 and a DC-AC conversion unit 104. The conversion module 102 is coupled to the mains Vac, the DC power supply Vdc and the control unit 20, and the control unit 20 controls the conversion module 102 to convert the mains Vac or the DC power supply Vdc into the bus voltage Vbus. The DC-AC conversion unit 104 is coupled to the conversion module 102 and the load 200, and the DC-AC conversion unit 104 converts the bus voltage Vbus into the output power Vo. It is hereby explained that the position of the control unit 20 is not limited to the outside or inside of the uninterruptible power device 10, as long as the control purpose can be achieved. When the control unit 20 wants to adjust the ratio of the commercial power Vac and the DC power supply Vdc to the load power supply (hereinafter referred to as the load ratio), the control unit 20 slowly adjusts the load ratio occupied by the DC power supply Vdc by controlling the conversion module 102 (for example, but Not limited to slowly adjusting from 0% to 50%). Then, according to the slow step adjustment of the load ratio occupied by the DC power supply Vdc, the load ratio occupied by the mains Vac is correspondingly adjusted backward stepwise (for example, but not limited to reverse step adjustment from 100% to 50%). Specifically, the control unit 20 controls the conversion module 102 according to the power command Cp, so that the conversion module 102 gradually increases or decreases the first average power provided by the DC power supply Vdc, and then slowly adjusts the amount of the DC power supply Vdc. Load ratio. The power command Cp can be provided by an external device (for example, but not limited to, a remote control device, etc.), or provided by the control unit 20 to detect the actual operating status of the power conversion system 100 (not shown in the figure, for example, but not limited to, detection Test load 200, mains Vac or DC power Vdc, etc.).

When the first average power is adjusted slowly, the bus voltage Vbus corresponding to the slow variation of the first average power will theoretically change accordingly, but the control unit 20 correspondingly controls the conversion module 102 according to the bus voltage Vbus to make the conversion The module 102 slowly adjusts the second average power corresponding to Vac (corresponding to the reverse slow step adjustment of the first average power), so that when the load ratio of the DC power supply Vdc is gradually increased or decreased, the mains Vac The proportion of the load is correspondingly reduced or increased gradually.

Furthermore, since the power conversion system 100 of the present invention uses the flexible switching technology of slow step adjustment when the load is switched between the commercial power Vac and the DC power supply Vdc, the front end of the uninterruptible power device 10 does not need to be additionally coupled to the automatic switching Switch, so that the uninterruptible power device 10 can avoid the inrush current generated when the switch is automatically switched, and the flexible switching technology of slow step adjustment can be used to easily and accurately distribute the load (for example, but not limited to accurately The distribution city power Vac is 48%, and the direct current power supply Vdc is 52%).

Please refer to FIGS. 2A~2C for schematic diagrams of power transmission of the first to third embodiments of the power conversion system of the present invention, and FIGS. 3A~3B for the power consumption of the first to second embodiments of the power conversion system of the present invention Refer to Figure 1 for compound coordination, and refer to Figures 2A~3B repeatedly. The power conversion system 100 further includes a DC power supply module 30. The DC power supply module 30 is coupled to the conversion module 102 and provides a DC power Vdc to the conversion module 102. The DC power supply module 30 may include a generator module 302, a renewable energy module 304, and an energy storage module 306. The generator module 302 includes a generator 302-1 and an AC-DC converter 302-2. The AC-DC converter 302-2 can be a rectifier circuit to convert the electric energy generated by the generator 302-1 into a first power source V1. And the first power V1 is provided to the conversion module 102. The renewable energy module 304 includes a renewable energy unit 304-1 and a DC-DC converter 304-2. The DC-DC converter 304-2 converts the electrical energy generated by the renewable energy unit 304-1 into a second power source V2, and The second power V2 is provided to the conversion module 102. The energy storage module 306 may be, for example, but not limited to, a battery pack for providing the third power V3 to the conversion module 102. It is hereby explained that the generator, which is different from the traditional power conversion system, is located at the AC input end. The generator module of the present invention 302 is used to provide DC power Vdc. Such a configuration combined with the control of the present invention can solve the problems mentioned in the prior art.

2A and 3A, when the required power is greater than or equal to the predetermined power A, the control unit 20 controls the mains Vac and the DC power Vdc to supply power to the load 200 according to the power command Cp. For example, but not limited to, the predetermined power source A can be the demarcation point of the power consumption calculation step. When the demand power is too high and the power provided by the mains Vac is greater than or equal to the predetermined power source A, the extra power consumption will have to be paid extra Relatively high cost. When the demand for power is low and the power provided by the mains Vac is less than the predetermined power A, a relatively low cost will be paid for the lower power consumption.

As shown in Figures 3A and 3B, the vertical axis P of the coordinates represents power, and the horizontal axis t represents time. When the power consumption peak period T1 (as shown in FIG. 3A), the demand power of the load 200 is greater than or equal to the predetermined power A. At this time, the control unit 20 controls the conversion module 102 to convert the DC power supply Vdc provided by the generator module 302, the renewable energy module 304 or the energy storage module 306, gradually increase the load ratio of the DC power supply Vdc, and slowly Reduce the load ratio of the mains Vac (for example, but not limited to, the energy storage module 306 and the renewable energy module 304 jointly provide the DC power supply Vdc, or the energy storage module 306 separately provides the DC power supply Vdc). Through the function of the mains Vac and the DC power supply Vdc to supply power to the load 200 during the peak period T1, the peak energy saving effect is achieved. And during the functional test of the generator 302-1, there is no need to add an additional generator test load (Load Bank), but directly use the control unit 20 to control the conversion module 102 to transfer the load ratio, which can complete the generator 302 -1 function test (that is, online online test), so it can achieve the effect of not needing to invest in additional generator test load, and greatly reducing the cost of system construction.

2B and 3A, when the required power is less than the predetermined power A, the control unit 20 controls the conversion module 102 to make the mains Vac supply power to the load 200, and controls the conversion module 102 to make the mains Vac charge the energy storage module 306. During the ionization peak period T2 (as shown in FIG. 3A), the demand power of the load 200 is less than the predetermined power A. At this time, the control unit 20 in addition to controlling the conversion module 102 makes the mains Vac supply power to the load 200 In addition, at the same time, the conversion module 102 is also controlled to charge the energy storage module 306 (as shown in FIG. 2B) when the mains Vac is less than the predetermined power supply A (indicated by the dotted line).

2C and 3B, the conversion module 102 can be a bidirectional conversion module, and the control unit 20 can control the conversion module 102 to convert the DC power supply Vdc to the mains Vac through the bidirectional conversion module, and feed the mains Vac back to the power company (Picture not shown). As shown in FIG. 3B, more than 0% of the power is the demand power required by the load 200, and the power below 0% is the extra redundant power B (indicated by the dotted line) generated by the renewable energy module 304. When the regenerative energy module 304 supplies power to the load 200 and there is redundant power B, the control unit 20 controls the conversion module 102 to convert the redundant power B into the commercial power Vac through the bidirectional conversion module, and will be converted from the redundant power B The mains Vac is fed back to the power company (as shown in Figure 2C). Since the power generation of renewable energy is not stable, when the power of the renewable energy is supplied to the load 200, when there is additional redundant power B (as shown in Figure 3B), in addition to the additional redundant power B can be stored in energy storage In addition to the module 306, the extra redundant power B can be converted into the mains Vac through the two-way conversion module, and the mains Vac is fed back to the power company (not shown), so that renewable energy can supply the company without loss Bulk purchase to achieve economic benefits.

Please refer to FIG. 4A for the circuit block diagram of the first embodiment of the conversion module of the present invention. Please refer to FIGS. 1 to 3B for cooperation, and refer to FIGS. 1 and 4A repeatedly. The conversion module 102 includes a DC-DC conversion unit 102-1 and an AC-DC conversion unit 102-2. The DC-DC conversion unit 102-1 is coupled to the DC power supply Vdc and the DC-AC conversion unit 104, and the AC-DC conversion unit 102-2 is coupled to the mains Vac and the DC-AC conversion unit 104. The DC-DC conversion unit 102-1 converts the DC power supply Vdc into the bus voltage Vbus, and provides the first current I1 to the node N according to the demand of the load 200 and the control of the control unit 20. Therefore, the first average power provided by the DC power supply Vdc corresponds to the first current I1 output by the DC-DC conversion unit 102-1 according to the relationship between the input power and the output power (excluding the loss of conversion efficiency). The AC-DC conversion unit 102-2 converts the mains Vac into the bus voltage Vbus, and provides the second current I2 to the node N according to the demand of the load 200 and the control of the control unit 20. Therefore, the second average power provided by the mains Vac According to the relationship between the input power and the output power (excluding the loss of conversion efficiency), it will correspond to the input current Ii of the AC-DC conversion unit 102-2 and the output second current I2. When the second current I2 changes, the second average power also changes with the change of the second current I2.

When the control unit 20 wants to increase the load ratio of the DC power supply Vdc (for example, from 0% to 50%), the control unit 20 slowly increases the first current I1 provided by the DC-DC conversion unit 102-1 according to the power command Cp , So that the first average power is correspondingly increased gradually. The DC-DC conversion unit 102-1 can be controlled by controlling the first duty cycle. The principle is equivalent to controlling the DC-DC conversion unit 102-1 to operate in the current mode . When the first current I1 changes, the bus voltage Vbus on the node N will theoretically change due to the increase of the first current I1, but the control unit 20 will control the AC-DC conversion unit 102-2 to change the bus voltage on the node N The voltage Vbus is maintained at the predetermined output voltage Vp, and the second current I2 output by the AC-DC conversion unit 102-2 is adjusted. Therefore, when the first current I1 is gradually increased, the control unit 20 adjusts the second duty cycle according to the variation of the bus voltage Vbus, so that the second current I2 output by the AC-DC conversion unit 102-2 is gradually decreased, and then As a result, the second average power is gradually reduced, and the load ratio of the mains Vac is gradually reduced (correspondingly reduced from 100% to 50%). It is worth mentioning that when the control unit 20 wants to lower the load ratio of the DC power supply Vdc, the operation is exactly the opposite of the higher load ratio, which is not repeated here.

Please refer to FIG. 4B for the control block diagram of the first embodiment of the conversion module of the present invention. Please refer to FIGS. 1 to 4A for cooperation, and refer to FIGS. 4A and 4B repeatedly. As shown in FIG. 4B, the control of the DC-DC conversion unit 102-1 is the current mode DC_I_mod. In the current mode DC_I_mod, the control unit 20 subtracts the current power value Pc (known by detection) of the DC-DC conversion unit 102-1 according to the power command Cp to obtain the power difference. After the power difference is amplified and calculated by the control parameter Gpc, the first DC current command Ci1 is obtained. The first current command Ci1 is subtracted from the first current I1 (known by detection) output by the DC-DC conversion unit 102-1 to obtain a first current difference, and the first current difference is amplified by the control parameter Gic_dc Then the first control amount is obtained. The control unit 20 adjusts the first duty ratio of the DC-DC conversion unit 102-1 according to the first control amount to adjust the first current I1 output by the DC-DC conversion unit 102-1.

Referring again to FIG. 4B, the control of the AC-DC conversion unit 102-2 is the voltage mode AC_V_mod. When the first current I1 is adjusted, the bus voltage Vbus will change accordingly. The control unit 20 subtracts the bus voltage Vbus from the predetermined output voltage Vp set and output by the AC-DC conversion unit 102-2 to obtain a voltage difference. After the voltage difference is amplified by the control parameter Gvc and multiplied by a sine wave (the waveform of the mains Vac is a sine wave), the AC second current command Ci2 is obtained. The second current command Ci2 is subtracted from the input current Ii of the AC-DC conversion unit 102-2 (known through detection) to obtain a second current difference, and the second current difference is amplified by the control parameter Gic_ac to obtain the first 2. Control amount. The control unit 20 adjusts the second duty cycle of the AC-DC conversion unit 102-2 according to the second control amount to control the input current Ii of the AC-DC conversion unit 102-2, and then adjust the output second current I2. It is worth mentioning that in the embodiment of the present invention, the AC-DC conversion unit 102-2 has a power factor correction function, so the waveform of the input current Ii will follow the voltage waveform of the mains Vac, so multiplying the voltage difference by the sine wave is To make the generated second current command Ci2 become an alternating current command waveform. It is hereby explained that because the AC current changes constantly, the present invention uses the concept of average power to discuss. For example, the second slow average power reduction can be understood as a gradual decrease in the peak value of the AC current, but the shape still roughly conforms to the sine wave to maintain the power factor. In addition, FIG. 4B is a control block diagram of the first embodiment of the conversion module of the present invention. The control circuit of the DC-DC conversion unit 102-1 and the control circuit of the AC-DC conversion unit 102-2 may be collectively referred to as the control unit 20. Please refer to FIG. 5 for a schematic diagram of a circuit block diagram of the second embodiment of the conversion module of the present invention. Please refer to FIGS. 1 to 4B for cooperation, and refer to FIGS. 1 and 5 repeatedly. The difference between this embodiment and the embodiment in FIG. 4A is that the conversion module 102' includes a first switching bridge arm 1022, a second switching bridge arm 1024, a first boosting unit 1026, and a second boosting unit 1028. The first switching bridge arm 1022 includes a first switch Q1 and a second switch Q2 connected in series, and the mains Vac is coupled to one end of the first switch Q1 and the second switch Q2. The DC power supply Vdc includes a first DC source Vdc1 and a second DC source Vdc2 connected in series, and the first DC source Vdc1 and the second DC source Vdc2 are commonly coupled One end is the midpoint end. The second switching bridge arm 1024 includes a third switch Q3 and a fourth switch Q4 connected in series, and one end of the third switch Q3 is coupled to the other end of the first direct current source Vdc1, and one end of the fourth switch Q4 is coupled to the second direct current source The other end of Vdc2. The first switching bridge arm 1022 is connected in parallel with the second switching bridge arm 1024, so that the other end of the first switch Q1 is coupled to the other end of the third switch Q3, and the other end of the second switch Q2 is coupled to the other end of the fourth switch Q4.

The first boost unit 1026 includes a first inductor L1, a first power switch S1, a first diode D1, and a first capacitor C1. One end of the first inductor L1 is coupled to the other end of the third switch Q3, and the other end of the first inductor L1 is coupled to the first power switch S1 and one end of the first diode D1. The other end of the first diode D1 is coupled to one end of the first capacitor C1, and the other end of the first power switch S1, the other end of the first capacitor C1 and the mains Vac are coupled to the midpoint end of the DC power supply Vdc. The second boost unit 1028 includes a second inductor L2, a second power switch S2, a second diode D2, and a second capacitor C2, and is opposite to the first boost unit 1026 and is coupled to the other end of the fourth switch Q4 The midpoint end of the DC power supply Vdc. It is worth mentioning that in an embodiment of the present invention, the first switch Q1 to the fourth switch Q4 are silicon-controlled diodes, but it is not limited thereto. In other words, as long as the switchable switching element is included in the scope of this embodiment.

Specifically, the conversion module 102' is characterized in that the conversion module 102' is a conversion circuit that operates half of the mains Vac and the other half of the DC power Vdc. When the first boosting unit 1026 converts half of the AC source, the second boosting unit 1028 simultaneously converts the DC source. When the mains Vac is in the positive half cycle, the control unit 20 controls the first switching bridge arm 1022 to switch on the first switch Q1 so that the positive half cycle of the mains Vac is provided to the first boost unit 1026 through the first switch Q1. The control unit 20 controls the switching of the first power switch S1, so that the first inductor L1 is stored or discharged to generate a second current I2, and the second current I2 charges the first capacitor C1 to establish a first capacitor C1. Bus voltage Vbus1. During this half-cycle of the mains Vac, the control unit 20 controls the second switching bridge arm 1024 to switch on the fourth switch Q4, so that the DC power Vdc is provided to the second boost unit 1028 through the fourth switch Q4. The control unit 20 controls the switching of the second power switch S2, so that the second inductor L2 stores or discharges energy to generate a fourth current I4, and the fourth current I4 affects the second capacitor C2 is charged to establish a second bus voltage Vbus2 on the second capacitor C2. The sum of the first bus voltage Vbus1 and the second bus voltage Vbus2 is the bus voltage Vbus. When the mains power Vac is in the negative half cycle, the method of using the first current I1 to establish the first bus voltage Vbus1 and the third current I3 to establish the second bus voltage Vbus2 is exactly the opposite of the positive half cycle, and will not be repeated here.

Furthermore, since the first boosting unit 1026 generates the second current I2 according to the mains power Vac during one and a half cycles, and generates the first current I1 according to the DC power supply Vdc during the other half cycle. Therefore, when the first current I1 changes, the first average power also changes with the first current I1, and the first bus voltage Vbus1 changes with the first current I1. When the first bus voltage Vbus1 changes, the control unit 20 will adjust the second current I2 in the next half cycle so that the second average power will also change with the change of the second current I2. The operation of the second boosting unit 1028 is also the same, and will not be repeated here.

When the control unit 20 wants to increase the load ratio of the DC power supply Vdc (for example, from 0% to 50%), the control unit 20 increases the first current I1 provided by the first boost unit 1026 in the negative half cycle according to the power command Cp , In turn, the first average power is correspondingly increased, and the first bus voltage Vbus1 will vary due to the variation of the first current I1. When the first bus voltage Vbus1 changes, the control unit 20 controls the first boost unit 1026 to maintain the first bus voltage Vbus1 at a predetermined output voltage, and then adjusts the first boost unit 1026 to be in the positive half cycle (meaning the mains Vac input) the output second current I2. Therefore, when the first current I1 is gradually increased, the control unit 20 adjusts the second duty cycle according to the variation of the first bus voltage Vbus1, so that the second current I2 is gradually reduced, so that the second average power corresponds to Is gradually reduced, and the load ratio of the mains Vac is gradually reduced (correspondingly reduced from 100% to 50%). It is worth mentioning that the operation of the second boosting unit 1028 is also the same, and when the control unit 20 wants to lower the load ratio of the direct current power supply Vdc, the operation is exactly the opposite of the higher operation, which will not be repeated here.

Please refer to FIG. 6 for a schematic diagram of the control block diagram of the second embodiment of the conversion module of the present invention. The control block of the conversion module 102’ is actually the first The boosting unit 1026 is an independent group of control blocks, and the second boosting unit 1028 is an independent group of control blocks. The method is the same, but the signal is different. For the convenience of description, this embodiment combines two sets of control blocks for description. As shown in FIG. 6, the control unit 20 according to the power command Cp and the first power value Pc1 of the first boosting unit 1026 in the negative half cycle (the current power value is known through detection, and the second boosting unit 1028 is The second power value Pc2) is subtracted to obtain the first power difference. After the first power difference is amplified by the control parameter Gpc and multiplied by the square wave, the first DC current command Ci1 is obtained. The control unit 20 subtracts the first bus voltage Vbus1 and the first predetermined output voltage Vp1 set and output by the first boost unit 1026 (in the second predetermined output voltage Vp2 in the second boost unit 1028) to obtain a first voltage difference value. After the first voltage difference is amplified by the control parameter Gvc and multiplied by the sine wave (as shown in the figure), the AC second current command Ci2 is obtained.

As shown in the waveform of FIG. 6, the control unit 20 synthesizes the first current command Ci1 and the second current command Ci2 into the first total current command Cit1 (in the second boost unit 1028, the control unit 20 synthesizes the third current command Ci3 and the first current command Ci3). The four current command Ci4 is the second total current command Cit2). The second current command Ci2 is the AC sine wave current command corresponding to the mains Vac when the mains Vac is in the positive half cycle (solid line), and the first current command Ci1 corresponds to the DC square wave current of the DC power Vdc when the mains is in the negative half cycle. Command (represented by a solid line). From the control diagram, it can be seen that the combination of the two current commands is the first total current command Cit1 with alternating sine wave and square wave, that is, the input current of the first boost unit 1026 will follow The first total current command to realize our invention. The first total current command Cit1 is subtracted from the first input current Ii1 of the first boost unit 1026 (known by detection) to obtain the first total current difference, and the first total current difference is amplified by the control parameter Gic And get the first control amount. The control unit 20 adjusts the first duty ratio of the first boost unit 1026 when the mains Vac is in the negative half cycle according to the first control amount, so as to adjust the first current I1 provided by the DC power supply Vdc, and adjust the first boost unit 1026 is the second duty cycle when the mains Vac is in the positive half cycle to adjust the second current I2 provided by the mains Vac.

It is worth mentioning that the control block operation of the second boosting unit 1028 is also the same. The sine wave and square wave commands in FIG. 6 are represented by dashed lines, which will not be repeated here. In addition, in the embodiment of the present invention, the first boost unit 1026 and the second boost unit 1028 have a power factor correction function, so that the waveforms of the first input current Ii1 and the second input current Ii2 follow the voltage of the mains Vac Therefore, the purpose of multiplying the first voltage difference by the sine wave is to make the generated second current command Ci2 become an alternating current command waveform.

However, the above are only detailed descriptions and drawings of the preferred embodiments of the present invention. However, the features of the present invention are not limited to these, and are not intended to limit the present invention. The full scope of the present invention should be referred to the following application The scope of the patent shall prevail. All embodiments that conform to the spirit of the scope of the patent application of the present invention and similar variations should be included in the scope of the present invention. Anyone familiar with the art in the field of the present invention can easily think of it. Changes or modifications can be covered in the following patent scope of this case.

100: Power Conversion System

10: Uninterruptible power device

102: conversion module

104: DC-AC conversion unit

20: control unit

200: load

Vac: mains

Vdc: DC power supply

Vbus: bus voltage

Vo: output power

Cp: power command

Claims (11)

A power conversion system supplies power to a load, and the power conversion system includes: an uninterruptible power device, including: a conversion module, coupled to a city power supply and a DC power supply to convert the city power and the DC power supply into one Bus voltage, the conversion module includes: an AC-DC conversion unit coupled to the mains; and a DC-DC conversion unit coupled to the DC power supply; and a DC-AC conversion unit coupled to the AC-DC conversion Unit and the DC-DC conversion unit, and convert the bus voltage to supply power to the load; a generator module, coupled to the DC power source; and a control unit, coupled to the conversion module; wherein the control unit is based on a The power command controls the conversion module so that a first average power provided by the DC power supply is gradually increased or decreased; the control unit controls the conversion module according to the bus voltage so that a second average power provided by the mains The first average power should be gradually reduced or increased; the control unit adjusts a first duty cycle of the DC-DC conversion unit according to the power command so that the first average power provided by the DC-DC conversion unit corresponds to A first current of the AC-DC conversion unit is gradually increased or decreased; the control unit adjusts a second duty cycle of the AC-DC conversion unit according to the bus voltage so that the second average power provided by the AC-DC conversion unit corresponds to The control unit calculates a second current command according to a voltage difference between the bus voltage and a predetermined output voltage set by the AC-DC conversion unit, and according to the second current Commands a second current difference between an input current of the AC-DC conversion unit to generate a second control value, and adjusts the second duty ratio according to the second control value. The power conversion system described in item 1 of the scope of patent application, wherein the control unit obtains a power difference according to the power command and a power value of the DC-DC conversion unit, and calculates a first current according to the power difference Command; the control unit generates a first control amount according to a first current difference between the first current command and the first current, and adjusts the first duty cycle according to the first control amount. For example, the power conversion system described in item 1 of the scope of patent application further includes: a renewable energy module coupled to the conversion module and the control unit; and an energy storage module coupled to the conversion module and the control unit Unit; wherein the control unit selectively controls the generator module, the regenerative energy module or the energy storage module to provide the DC power source to the conversion module according to a demand power source of the load. According to the power conversion system described in item 3 of the scope of patent application, when the demand power is greater than or equal to a predetermined power source, the control unit controls the mains and the DC power source to supply power to the load according to the power command. For example, in the power conversion system described in item 4 of the scope of patent application, when the required power is less than the predetermined power, the control unit controls the mains power to supply power to the load, and controls the mains to charge the energy storage module. For example, the power conversion system described in item 3 of the scope of patent application, wherein the conversion module is a two-way conversion module. When the renewable energy module supplies power to the load and still has a redundant power, the control unit controls The redundant power is converted into the mains power through the bidirectional conversion module. A power conversion system supplies power to a load, and the power conversion system includes: an uninterruptible power device, including: a conversion module, coupled to a city power supply and a DC power supply to convert the city power and the DC power supply into one Bus voltage, the conversion module includes: a first switching bridge arm, including a first terminal, a second terminal and a power terminal, the power terminal is coupled to the mains; A second switching bridge arm includes a first end, a second end, and a power terminal. The first end is coupled to the first end of the first switching bridge arm, and the second end is coupled to the first switching bridge. The second end of the bridge arm, and the power end is coupled to the DC power supply; a first boost unit includes a power end and a midpoint end, the power end is coupled to the first switching bridge arm Terminal, and the midpoint terminal is coupled to the mains and the DC power supply; and a second boost unit, including a power terminal and a midpoint terminal, the power terminal is coupled to the second end of the second switching bridge arm , And the midpoint terminal is coupled to the mains and the DC power supply; a DC-AC conversion unit is coupled to the first boost unit and the second boost unit, and converts the bus voltage to supply power to the load; The motor module is coupled to the DC power supply; and a control unit is coupled to the conversion module; wherein, the control unit controls the conversion module according to a power command to slow down a first average power provided by the DC power supply The control unit controls the conversion module according to the bus voltage, so that a second average power provided by the mains is gradually reduced or increased corresponding to the first average power; when the mains is in the positive half-cycle, the The control unit controls the switching of the first switching bridge arm to provide the mains power to the first boosting unit, so that the first boosting unit generates a first bus voltage, and the control unit controls the switching of the second switching bridge arm Switch to provide the DC power to the second boost unit, so that the second boost unit generates a second bus voltage; and when the mains is in the negative half cycle, the control unit controls the switching of the first switching bridge arm The mains is provided to the second boost unit, the second boost unit generates the second bus voltage, and the control unit controls the switching of the second switching bridge arm to provide the DC power to the first A boosting unit, causing the first boosting unit to generate the first bus voltage; the sum of the first bus voltage and the second bus voltage is the bus voltage; The control unit adjusts a first duty cycle of the first boost unit in the negative half cycle according to the power command, so that a first current corresponding to the first average power is gradually increased or decreased; the control unit Adjust a second duty cycle of the first boost unit in the positive half cycle according to the first bus voltage, so that a second current corresponding to the second average power can be gradually reduced or decreased corresponding to the first current Increase; and the control unit adjusts a third duty cycle of the second boost unit in the positive half cycle according to the power command, so that a third current corresponding to the first average power is gradually increased or decreased; The control unit adjusts a fourth duty ratio of the second boost unit in the negative half cycle according to the second bus voltage, so that a fourth current corresponding to the second average power can be slow to correspond to the third current To reduce or increase. The power conversion system described in item 7 of the scope of patent application, wherein the control unit calculates a first current command according to the power command; the control unit calculates a first current command according to the first bus voltage and the first boost unit A first voltage difference of the predetermined output voltage calculates a second current command; the control unit synthesizes the first current command and the second current command into a first total current command, and according to the first total current command and the An input current of the first boost unit generates a first control quantity, and the control unit adjusts the first duty ratio and the second duty ratio according to the first control quantity. An operation method of a power conversion system includes: controlling a conversion module to convert a mains and a DC power supply into a bus voltage, the conversion module including an AC-DC conversion unit and a DC-DC conversion unit; controlling the DC- The AC conversion unit converts the bus voltage to supply power to a load; controls a generator module to provide electrical energy to the DC power source; controls a first average power provided by the DC power source to gradually increase or decrease according to a power command; The bus voltage controls a second average power provided by the mains to gradually decrease or increase in response to the first average power; Adjust a first duty cycle of the DC-DC conversion unit according to the power command, so that a first current corresponding to the first average power is gradually increased or decreased; adjust the AC-DC conversion unit according to the bus voltage A second duty cycle of the second average power enables a second current corresponding to the second average power to be gradually reduced or increased corresponding to the bus voltage; according to the power command and a power value of the DC-DC conversion unit, a Power difference, and calculate a first current command according to the power difference; generate a first control value according to a first current difference between the first current command and the first current, and adjust according to the first control value The first duty cycle; and calculating a second current command according to a voltage difference between the bus voltage and a predetermined output voltage set by the AC-DC conversion unit, and calculating a second current command according to the second current command and the AC-DC conversion A second current difference value of an input current of the unit generates a second control value, and the second duty ratio is adjusted according to the second control value. An operation method of a power conversion system includes: controlling a conversion module to convert a mains power and a DC power supply into a bus voltage, the conversion module including a first boosting unit and a second boosting unit; controlling the DC- The AC conversion unit converts the bus voltage to supply power to a load; controls a generator module to provide electrical energy to the DC power source; controls a first average power provided by the DC power source to gradually increase or decrease according to a power command; The bus voltage controls a second average power provided by the mains power to gradually decrease or increase in response to the first average power; when the mains power is in the positive half-cycle, the mains power is provided to the first boosting unit to make the first boost The voltage unit generates a first bus voltage, and provides the DC power to the second voltage boost unit, so that the second voltage boost unit generates a second bus voltage; When the city power is in the negative half cycle, the city power is supplied to the second boost unit, the second boost unit generates the second bus voltage, and the DC power is supplied to the first boost unit, so that the The first boosting unit generates the first bus voltage; the sum of the first bus voltage and the second bus voltage is the bus voltage; adjusts the first boosting unit in the negative half cycle according to the power command A duty cycle to make a first current corresponding to the first average power gradually increase or decrease; adjust a second duty cycle of the first boost unit in a positive half cycle according to the first bus voltage , Enabling a second current corresponding to the second average power to gradually decrease or increase corresponding to the first current; adjust a third duty cycle of the second boost unit in the positive half cycle according to the power command , Make a third current corresponding to the first average power gradually increase or decrease; and adjust a fourth duty cycle of the second boost unit in the negative half cycle according to the second bus voltage to make the A fourth current corresponding to the second average power can be gradually decreased or increased corresponding to the third current. As described in item 10 of the scope of patent application, the operation method further includes: calculating a first current command according to the power command; according to a ratio of the first bus voltage and a first predetermined output voltage set by the first boost unit A second current command is calculated by the first voltage difference; the first current command and the second current command are synthesized into a first total current command, and according to the first total current command and a second current command of the first boost unit A first total current difference of an input current generates a first control quantity, and the first duty ratio and the second duty ratio are adjusted according to the first control quantity.

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