JP5849517B2 - Power system - Google Patents

Description

  The present invention relates to a power supply system capable of charging and discharging DC power.

In recent years, motors have been actively used as power generation sources in order to reduce the amount of carbon dioxide (CO ₂ ), which is a kind of greenhouse gas. For example, in an automobile or the like, an internal combustion engine such as an engine is generally used as a power generation source. However, in recent years, a hybrid vehicle (HV: Hybrid Vehicle) or a power that uses an engine and a motor together as a power generation source. Research and development of electric vehicles (EVs) that use only a motor as a generation source have been actively conducted.

  In an apparatus using a motor as a power generation source, a secondary battery such as a lithium ion secondary battery capable of charging and discharging DC power is used as a power source. When constructing a power supply system using a secondary battery as a power source, the system designer must include a secondary battery, a DC / DC converter that controls charging / discharging of the secondary battery, and an inverter that drives an electric device to be controlled. It is necessary to prepare equipment individually and combine these equipment to meet the specifications of the power supply system. Similarly, when building a large-capacity power supply system, it is necessary to obtain a large-capacity secondary battery (for example, several megawatts) and a large-capacity converter individually and combine them according to the specifications of the power supply system. is there.

  The following Patent Document 1 discloses a technique for improving the performance of a power supply device including a plurality of DC / DC converters connected in parallel between a direct current power source such as a solar battery and a load. Specifically, the number of operating DC / DC converters is such that the value obtained by dividing the total input or total output current value of the power supply device by the number of operating DC / DC converters is the closest value to the rated current value of the current sensor. A technique for improving the performance of a power supply device by controlling the power is disclosed.

JP 2010-144201 A

  By the way, in order to increase the capacity of the power supply system including the secondary battery and the DC / DC converter described above, for example, a plurality of secondary batteries are provided in parallel, and a DC / DC converter as described in Patent Document 1 described above is provided. It is conceivable to provide a plurality in parallel. At this time, it is considered that the configuration and controllability can be simplified if the secondary battery and the DC / DC converter are associated with each other on a one-to-one basis.

  Here, the charge / discharge current of the secondary battery is basically controlled based on the remaining capacity (SOC: State Of Charge) and the depth of discharge (DOD: Depth Of Discharge) of the secondary battery. For this reason, as described above, when the secondary battery and the DC / DC converter are united in a one-to-one correspondence, it is necessary to input / output in each unit on the assumption that all the units operate simultaneously. A certain current sharing is determined based on the SOC and DOD of the secondary battery provided in each unit.

  However, when the current input / output in the power supply system is shared by all the units, a situation may occur in which the charge / discharge current of the secondary battery provided in each unit becomes smaller than the capacity of the entire power supply system. When such a situation occurs, each unit operates in a state where the input / output current is lower than the preset rated current (low load factor). As a result, the conversion efficiency of the DC / DC converter provided in each unit is lowered, which may reduce the efficiency of the entire power supply system.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a power supply system capable of maintaining high efficiency even in a state where the input / output current is small.

In order to solve the above-described problems, the power supply system of the present invention has power input / output terminals (T11, T12) for inputting / outputting DC power connected in parallel, and the DC power is input via the power input / output terminals. A power supply system (PS) including a plurality of power supply devices (1) capable of charging and discharging, wherein the power supply device includes at least one battery module (10) and direct-current power charged / discharged with respect to the battery module. Information indicating a control amount of the power conversion circuit is obtained from a power conversion circuit (20) that performs power conversion and a command signal (C, C1) input from the outside, and the control of the power conversion circuit is performed based on the information. And a control unit (40) that performs a delay by a preset time.
The power supply system of the present invention is characterized in that a time for delaying control of the power conversion circuit is set for each of the power supply devices.
In the power supply system of the present invention, the control unit calculates a control amount calculation unit (51) that obtains information indicating a control amount of the power conversion circuit from the command signal, and a control amount obtained by the control amount calculation unit. And an operation unit (53) for obtaining a product of the control amount obtained by the control amount calculation unit and the output of the hysteresis comparator.
In the power supply system of the present invention, at least one of the power supply devices is set so that the hysteresis comparator operates when the control amount obtained by the control amount calculation unit is greater than zero. It is said.
Moreover, the power supply system of the present invention is characterized in that the power supply device is formed by unitizing the battery module, the power conversion circuit, and the control unit.
Further, in the power supply system of the present invention, the battery module is a module in which a battery cell and a monitoring board for monitoring the battery cell are modularized, and the control unit is provided for the monitoring board provided in the battery module. The power conversion circuit is controlled based on the information while referring to a monitoring result.
In the power supply system of the present invention, the power supply device includes a signal input / output terminal (T22) capable of inputting / outputting a signal including information indicating a monitoring result of the monitoring board.

  According to the present invention, the control unit provided in each of the power supply devices obtains information indicating the control amount of the command signal power conversion circuit input from the outside, and presets the control of the power conversion circuit based on the information Since the charging and discharging of the DC power to each of the power supply devices is performed in a ring by performing the delay for a certain amount of time, it is possible to maintain high efficiency even when the input / output current is small. There is an effect that there is.

It is a circuit diagram which shows the principal part structure of the power supply system by one Embodiment of this invention. It is a figure which extracts and shows the block which concerns on the control at the time of the pressure | voltage rise (discharge) driving | operation of the power supply system by one Embodiment of this invention. It is a figure which extracts and shows the block which concerns on the control at the time of the pressure | voltage fall (charge) driving | operation of the power supply system by one Embodiment of this invention.

  Hereinafter, a power supply system according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a circuit diagram showing a main configuration of a power supply system according to an embodiment of the present invention. As shown in FIG. 1, in the power supply system PS of the present embodiment, the power input / output terminals T11 and T12 are connected in parallel and the signal input / output terminal T22 is connected to each other, via the power input / output terminals T11 and T12. A plurality of power supply devices 1 capable of charging / discharging DC power are provided.

  One of the plurality of power supply devices 1 provided in the power supply system PS is a master power supply device M, and the rest is a slave power supply device S. Here, the master power supply device M includes a signal input / output terminal T21 to which a command signal C (for example, a voltage command signal) indicating the amount of DC power to be charged / discharged is input. It is a power supply device that performs overall control of the amount of DC power to be charged and discharged by each power supply device S. The slave power supply device S is a power supply device that charges and discharges DC power under the control of the master power supply device M.

  The power supply system PS having such a configuration can change the capacity by increasing or decreasing the parallel number of the slave power supply devices S. Specifically, the capacity of the power supply system PS can be increased by increasing the parallel number of the slave power supply devices S, and conversely, the capacity of the power supply system PS can be decreased by decreasing the parallel number of the slave power supply devices S. Can be made. The power supply system PS is connected to an inverter INV that converts DC power into AC power, for example.

  Specifically, the master power supply device M is a power source in which the battery module 10, the DC / DC converter 20 (power conversion circuit), the current sensor 31, the voltage sensor 32, and the controller 40 (control unit) are unitized. The master power supply device M is a power supply device (so-called bipolar power supply device) capable of charging and discharging DC power via a pair of power supply input / output terminals T11 and T12.

  The battery module 10 is obtained by modularizing a battery cell and a battery monitoring board (monitoring board), and at least one battery module 10 is provided in the master power supply device M. The number of battery modules 10 (the number of series connections) is appropriately set according to specifications such as the output voltage and capacity of the master power supply device M. Here, the battery cell is formed by stacking a plurality of single battery cells such as lithium ion secondary battery cells. The battery monitoring board is a board for monitoring the voltage / current of the battery cell, and is provided for each battery cell.

  The DC / DC converter 20 is provided between the battery module 10 and the pair of power supply input / output terminals T11 and T12, and the DC power discharged from the battery module 10 or the battery module under the control of the controller 40. 10 is converted into DC power (DC power input via a pair of power input / output terminals T11 and T12). The DC / DC converter 20 includes a capacitor 21, a choke coil 22, transistors 23a and 23b, diodes 24a and 24b, and a capacitor 25.

  The capacitor 21 is connected between the positive electrode and the negative electrode of the battery module 10. The negative electrode of the battery module 10 is connected to the power input / output terminal T12. The capacitor 21 is provided for smoothing the power supplied to the battery module 10 into a direct current when the master power supply M is charged (when the battery module 10 is charged).

  The choke coil 22 has one end connected to one electrode of the capacitor 21 (the electrode connected to the positive electrode of the battery module 10), and the other end connected to the collector electrode of the transistor 23a and the emitter electrode of the transistor 23b. It is connected to the. The transistors 23 a and 23 b are bipolar transistors, and the on state and the off state are controlled by the controller 40. Note that FET transistors (Field Effect Transistors) may be used as the transistors 23a and 23b.

  The transistor 23a has a collector electrode connected to the emitter electrode of the transistor 23b and the other end of the choke coil 22, and an emitter electrode connected to the other electrode of the capacitor 21 (the negative electrode of the battery module 10 and the power input / output terminal T12). Electrode). The transistor 23b has an emitter electrode connected to the collector electrode of the transistor 23a and the other end of the choke coil 22, and a collector electrode connected to one electrode of the capacitor 25 and the power input / output terminal T11. The base electrodes of these transistors 23a and 23b are connected to the controller 40.

  The diodes 24a and 24b are connected between the collectors and emitters of the transistors 23a and 23b, respectively. Specifically, the diode 24a has an anode electrode connected to the emitter electrode of the transistor 23a and a cathode electrode connected to the collector electrode of the transistor 23a. The diode 24b has an anode electrode connected to the emitter electrode of the transistor 23b and a cathode electrode connected to the collector electrode of the transistor 23b. The capacitor 25 is connected between the pair of power input / output terminals T11 and T12. The capacitor 25 is provided to smooth the power output from the power input / output terminals T11 and T12 to the DC current when the master power supply M is discharged.

  The current sensor 31 is attached to a current path that connects the positive electrode of the battery module 10 and the DC / DC converter 20, and a current flowing out from the battery module 10 (discharge current) and a current flowing into the battery module 10 ( Charge current). The voltage sensor 32 is attached in parallel to the capacitor 25 and detects a potential difference of the capacitor 25 (voltage appearing between the power input / output terminals T11 and T12). Detection signals indicating detection results of the current sensor 31 and the voltage sensor 32 are output to the controller 40.

  The controller 40 includes an arithmetic unit 41, an automatic voltage regulator (AVR) 42, a current command value generation unit 43, an arithmetic unit 44, an automatic current controller (ACR) 45, and a PWM controller 46. Is provided. Information (for example, current command value) indicating the control amount of the DC / DC converter 20 is obtained from the command signal C input from the signal input / output terminal T21, and control of the DC / DC converter 20 based on this information is performed in advance. Delayed by the set time.

  The blocks provided in the controller 40 may be realized by hardware or may be realized by software. When implemented by software, the controller 40 is configured using a CPU, memory, etc., and a program for realizing the function of each block is read by the CPU, and the program and hardware resources such as the CPU cooperate with each other. Realized.

  The calculator 41 subtracts the detection result of the voltage sensor 32 from the command signal C input from the signal input / output terminal T21 to obtain a voltage error signal indicating the difference between them. The automatic voltage controller 42 outputs a control signal that makes the voltage error signal output from the calculator 41 zero. The current command value generation unit 43 refers to the monitoring result of the battery module 10 (including the battery module 10 provided in the slave power supply device S), and based on the control signal from the automatic voltage controller 42, the master power supply device A current command value that is a command value that indicates the amount of DC power to be converted by the DC / DC converter 20 included in M is obtained. The current command value generation unit 43 outputs a signal C1 including a control signal from the automatic voltage controller 42 and a signal indicating the monitoring result of the battery module 10 to the signal input / output terminal T22.

  The calculator 44 subtracts the detection result of the current sensor 31 from the current command value generated by the current command value generation unit 43 to obtain a current error signal indicating the difference between them. The automatic current controller 45 generates and outputs a control signal that makes the current error signal output from the calculator 34 zero. The PWM controller 46 switches the transistors 23a and 23b provided in the DC / DC converter 20 based on the control signal from the automatic current controller 45 (PWM switching operation).

  Here, when the controller 40 turns off the transistor 23b and switches the transistor 23a, the DC / DC converter 40 operates as a non-insulated boost choke converter. For this reason, the DC power discharged from the battery module 10 is boosted in voltage and output to the outside via the power input / output terminals T11 and T12. This operation is performed when DC power is discharged from the battery module 10 provided in the master power supply device M.

  On the other hand, when the controller 40 turns off the transistor 23a and switches the transistor 23b, the DC / DC converter 40 operates as a non-insulated step-down choke converter. For this reason, the DC power input from the outside via the power input / output terminals T11 and T12 is supplied to the battery module 10 with the voltage lowered. This operation is performed when the battery module 10 provided in the master power supply device M is charged.

  The slave power supply device S is a bipolar power supply device whose basic configuration is almost the same as that of the master power supply device M. Specifically, the slave power supply device S is a power source in which the battery module 10, the DC / DC converter 20 (power conversion circuit), the current sensor 31, and the controller 40 (control unit) are unitized. However, the signal input / output terminal T21 and the voltage sensor 32 included in the master power supply device M are omitted, and the calculator 41 and the automatic voltage controller 42 are omitted in the controller 40.

  Unlike the controller 40 provided in the master power supply device M, the controller 40 provided in the slave power supply device S having such a configuration can control the control amount of the DC / DC converter 20 from the signal C1 input from the signal input / output terminal T22. Information (for example, current command value) to be shown is obtained, and the control of the DC / DC converter 20 based on this information is delayed by a preset time.

  Specifically, the current command value generation unit 43 is included in the signal C1 while referring to the monitoring result of the battery module 10 (including the battery module 10 provided in the master power supply device M and the other slave power supply device S). Based on the control signal, a current command value, which is a command value for instructing the amount of DC power to be converted by the DC / DC converter 20 provided in the device, is obtained. The control of the DC / DC converter 20 based on the generated current command value is performed similarly to the master power supply device S.

  Here, the delay time of the controller 40 provided in each of the master power supply device M and the slave power supply device S described above is set to a different time. Such a delay time is set by operating the power supply device 1 (master power supply device M, slave power supply device S) in a rotation number so that high efficiency is maintained even in a state where the input / output current is small. It is to do. That is, when all the power supply devices 1 are operated simultaneously, each power supply device 1 operates at a low load factor. Therefore, by operating the power supply device 1 as a wheel, each power supply device 1 is operated at a high load factor as much as possible. It is.

  The master power supply device M and the slave power supply device S have the same basic configuration. For this reason, it is possible to make these configurations exactly the same and select the master power supply device M or the slave power supply device S depending on the setting. For example, when the identification number assigned to identify each of the power supply devices 1 is “0”, the master power supply device M is selected, and when the identification number is other than “0”, the slave power supply S is selected. Further, depending on the type of program used in the controller 40, it may be determined whether to use the master power supply device M or the slave power supply device S.

  FIG. 2 is a diagram showing extracted blocks relating to control during the boost (discharge) operation of the power supply system according to the embodiment of the present invention. As shown in FIG. 2, the current command value generation unit 43 provided in the power supply device 1 (master power supply device M and slave power supply device S) includes a control amount calculation unit 51, a hysteresis comparator 52, a calculation unit 53, and a current limiting unit 54. Each is provided. In FIG. 2, signals denoted by reference numerals D1 and D2 indicate detection signals output from the voltage sensor 32 and the current sensor 31 included in the master power supply device M, respectively, and are denoted by reference numeral D3. The signal indicates a detection signal output from the current sensor 31 provided in each of the slave power supply devices S.

  The control amount calculation unit 51 refers to the remaining capacity (SOC1 to SOCn) of the battery module 10 provided in each of the master power supply device M and the slave power supply device S, and the automatic voltage provided in the controller 40 of the master power supply device M. Based on the control signal output from the controller 42 (or the control signal included in the signal C1), the control amount of the DC / DC converter 20 is obtained. That is, the control amount calculation unit 51 obtains the sharing of the current to be output in each of the master power supply device M and the slave power supply device S.

  The hysteresis comparator 52 receives the control amount obtained by the control amount calculation unit 51, and a preset time (delay time) has elapsed when the input control amount exceeds a preset threshold. Output at the time. Here, the hysteresis comparator 52 provided in the master power supply device M operates when the control amount obtained by the control amount calculation unit 51 is larger than the value “0”, and the control amount falls below a preset threshold value. Is set to stop (reset) the operation when The delay time of the hysteresis comparator 52 provided in each of the master power supply device M and the slave power supply device S is set to a different time.

  The calculation unit 53 calculates the product of the control amount obtained by the control amount calculation unit 51 and the output of the hysteresis comparator 52. In each of the master power supply device M and the slave power supply device S, the current limiter 54 restricts the discharge amount when the current according to the control amount obtained by the control amount calculation unit 51 cannot be discharged. Processing for generating a value (limiter processing) is performed.

  Next, an operation when the DC power is discharged in the power supply system PS will be described with reference to FIG. When a command signal C indicating that the DC power should be discharged is input from a signal input / output terminal T21 provided in the master power supply device M, first, the command signal C is provided by the arithmetic unit 41 provided in the master power supply device M. The voltage error signal is obtained by subtracting the detection result of the voltage sensor 32 from. This voltage error signal is input to an automatic voltage controller 42 provided in the master power supply device M, and the automatic voltage controller 42 generates a control signal that makes the voltage error signal zero.

  The control signal generated by the automatic voltage controller 42 is output to the current command value generation unit 43 provided in the slave power supply S in addition to the current command value generation unit 43 provided in the master power supply M. . Then, in each of the current command value generation units 43 provided in the master power supply device M and each slave power supply device S, a command value instructing the amount of DC power to be converted by the DC / DC converter 20 provided in the own device. A current command value is obtained.

  Specifically, in the control amount calculation unit 51 provided in the current command value generation unit 43, the own device for the total remaining capacity (SOC) of all the power supply devices 1 (master power supply device M and each slave power supply device S). The remaining capacity ratio is calculated, and the control amount of the DC / DC converter 20 provided in the own apparatus is obtained. Then, the control amount is output as a current command value through the calculation unit 53 and the current limiting unit 54 in order.

  Here, among the hysteresis comparators 52 provided in the master power supply device M and the slave power supply device S, only the hysteresis comparator 52 provided in the master power supply device M has the control amount calculated by the control amount calculation unit 51 as the value “ It is set to operate when it is greater than "0". Therefore, a current command value is output from the current command value generation unit 43 provided in the master power supply device M, but no current command value is output from the current command value generation unit 43 provided in the slave power supply device S. . Thus, immediately after the operation is started, only the DC power is discharged from the master power supply device M, and the DC power is not discharged from the slave power supply device S.

  As the value of the command signal C (the magnitude of the DC power to be discharged) gradually increases, the value of the control amount calculated by the control amount calculation unit 51 of the master power supply device M and each slave power supply device S also increases. In each of the slave power supply devices S, when the value of the control amount calculated by the control amount calculation unit 51 exceeds the threshold set in the hysteresis comparator 52, the slave power supply devices S operate in order from the one set with the shortest delay time. Thereby, the discharge of the DC power is sequentially started from the slave power supply device S in which the hysteresis comparator 52 is operated, and the number of the slave power supply devices S that discharge the DC power increases as the value of the command signal C increases. The timing at which discharge is started depends on the delay time set in the hysteresis comparator 52.

  On the other hand, when the value of the command signal C is gradually decreased, the value of the control amount calculated by the control amount calculation unit 51 of the master power supply device M and each slave power supply device S is also gradually decreased. In each of the master power supply device M and the slave power supply device S, when the value of the control amount calculated by the control amount calculation unit 51 is equal to or less than the threshold value set in the hysteresis comparator 52, the delay time is set in order from the shortest. Stop operation. As described above, the master power supply device M and each slave power supply device S stop operating in order from the one in which discharge is started first by the action of the hysteresis comparator 52. Note that the timing at which discharge is stopped also depends on the delay time set in the hysteresis comparator 52.

  As described above, in the present embodiment, the master power supply device M and each slave power supply device S operate in a ring by the action of the hysteresis comparator 52, and the DC power is discharged from each of the master power supply device M and each slave power supply device S. Is performed on the wheel number, and the discharge of the DC power is stopped on the wheel number. For this reason, it is possible to avoid a situation in which the discharge from only the specific power supply device 1 is continued, and it is possible to maintain high efficiency even in a state where the input / output current is small.

  FIG. 3 is a diagram illustrating extracted blocks relating to control during step-down (charging) operation of the power supply system according to the embodiment of the present invention. As shown in FIG. 3, the current command value generation unit 43 provided in the power supply device 1 (master power supply device M and slave power supply device S) replaces the control amount calculation unit 51 shown in FIG. 2 with a control amount calculation unit 61. And the division part 62 is provided. In FIG. 3, a signal indicated by reference numeral V1 indicates a signal indicating the output voltage of the battery module 10 provided in the master power supply apparatus M, and a signal indicated by reference numeral V2 indicates a slave power supply. The signal which shows the output voltage of the battery module 10 provided in each of the apparatuses S is shown.

  The control amount calculation unit 61 refers to the automatic voltage provided in the controller 40 of the master power supply device M while referring to the discharge depth (DOD1 to DODn) of the battery module 10 provided in each of the master power supply device M and the slave power supply device S. Based on the control signal output from the controller 42 (or the control signal included in the signal C1), the control amount of the DC / DC converter 20 is obtained. That is, the control amount calculation unit 51 determines the sharing of the charge amount of the battery module 10 in each of the master power supply device M and the slave power supply device S. The division unit 62 calculates a ratio between the control amount obtained by the control amount calculation unit 61 and the output voltage of the battery module 10 included in the own device.

  The operation when the DC power is charged in the power supply system PS is basically the same as the operation described with reference to FIG. In other words, the master power supply device M and each slave power supply device S operate in a rotation number by the action of the hysteresis comparator 52, and charging in each of the master power supply device M and each slave power supply device S is performed in a rotation number, and charging is stopped. It is done in a wheelchair. For this reason, detailed description here is omitted.

  As mentioned above, although the power supply system by one Embodiment of this invention was demonstrated, this invention is not restrict | limited to the said embodiment, It can change freely within the scope of the present invention. For example, the threshold value of the hysteresis comparator 52 provided in each of the master power supply device M and the slave power supply device S described in the above embodiment may be set to the same value or different values. The delay time of the hysteresis comparator 52 can be arbitrarily set according to the specifications required for the power supply system PS and the performance of the master power supply device M and the slave power supply device S.

DESCRIPTION OF SYMBOLS 1 Power supply device 10 Battery module 20 DC / DC converter 40 Controller 51 Control amount calculation part 52 Hysteresis comparator 53 Calculation part C Command signal C1 signal PS Power supply system T11, T12 Power input / output terminal T22 Signal input / output terminal

Claims (7)

A power supply system including a plurality of power supply devices capable of charging and discharging DC power via the power supply input / output terminals, wherein power supply input / output terminals for performing DC power input / output are connected in parallel,
The power supply device includes at least one battery module;
A power conversion circuit that performs power conversion of DC power charged and discharged with respect to the battery module;
From the command signal indicating the amount of DC power to be charged / discharged input from the outside, information indicating the control amount of the power conversion circuit from which the charge / discharge amount to be shared by the device is obtained , and based on the information A power supply system, comprising: a control unit that delays control of the power conversion circuit by a preset time.   The power supply system according to claim 1, wherein the time for delaying the control of the power conversion circuit is set to be different for each power supply device. The control unit is a control amount calculation unit for obtaining information indicating a control amount of the power conversion circuit from the command signal;
A hysteresis comparator that receives as input the control amount obtained by the control amount calculation unit;
The power supply system according to claim 1, further comprising: an arithmetic unit that calculates a product of the control amount obtained by the control amount calculation unit and the output of the hysteresis comparator.   4. The power supply according to claim 3, wherein at least one of the power supply devices is set so that the hysteresis comparator operates when a control amount obtained by a control amount calculation unit is greater than zero. system.   The power supply system according to any one of claims 1 to 4, wherein the power supply device is formed by unitizing the battery module, the power conversion circuit, and the control unit. The battery module is a module of a battery cell and a monitoring board for monitoring the battery cell,
The control unit controls the power conversion circuit based on the information while referring to a monitoring result of the monitoring board provided in the battery module. A power supply system according to any one of the above.   The power supply system according to claim 6, wherein the power supply device includes a signal input / output terminal capable of inputting / outputting a signal including information indicating a monitoring result of the monitoring board.

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