Power converter control device, program, and power converter control method

Abstract

A power supply system (10) comprises: a storage battery (11) having a first battery group (11A) and a second battery group (11B) connected in series to each other; and a first power converter (21A) and a second power converter (21B) each connected to both ends of each battery group. The power supply system supplies, to an electric load, output power after power conversion by each power converter. A control device (40) comprises: a difference calculation unit (43) for calculating a charge amount difference, which is a difference between charge amount parameters indicating the amount of charge stored in each battery group; an adjustment unit (44) for adjusting the output power of each power converter if the charge amount difference is greater than a predetermined threshold; and an acquisition unit (45) for acquiring charge / discharge information indicating the state of charge / discharge of the storage battery. The adjustment unit changes the implementation mode of power adjustment by each power converter on the basis of the acquired charge / discharge information.

Description

Control device, program, and method for controlling a power converter CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2024-060312 filed on April 3, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a control device for a power converter, a program, and a control method for a power converter.

[0003] A power supply system has been known in the past in which a power converter is connected across each end of a group of batteries connected in series with each other. Each power converter is used to redundantly supply power to an electrical load. An example of such a technology is disclosed in Patent Document 1.

[0004] Japanese Patent Application Laid-Open No. 2020-124060

[0005] It is desirable to appropriately implement a power supply system that redundantly supplies power from multiple power converters to an electrical load.

[0006] An object of the present disclosure is to provide a power converter control device, a program, and a power converter control method that can appropriately realize a power supply system that redundantly supplies power from multiple power converters to an electrical load.

[0007] The present disclosure provides a power converter control device applicable to a power supply system comprising: a storage battery having a first battery group and a second battery group connected in series with each other; and a first power converter and a second power converter connected to both ends of each battery group, respectively; and supplying output power after power conversion by each power converter to an electrical load; the control device comprising: a difference calculation unit that calculates a storage amount difference, which is a difference between storage amount parameters indicating the storage amount of each battery group; an adjustment unit that adjusts the output power by each power converter when the storage amount difference becomes larger than a predetermined threshold; and an acquisition unit that acquires charge / discharge information indicating the charge / discharge state of the storage battery; and the adjustment unit changes the implementation of power adjustment by each power converter based on the acquired charge / discharge information.

[0008] When power is redundantly supplied from each battery group in a storage battery to an electrical load, differences in the amount of stored power among the battery groups may occur. For example, if there is a difference in the path resistance of the electrical path between the electrical load and each power converter, differences in the amount of stored power among the battery groups may occur, and these differences may gradually increase. Therefore, it is possible to calculate a difference in the amount of stored power among the battery groups, and when the difference in amount of stored power exceeds a predetermined threshold, adjust the output power of each power converter to reduce the difference in amount of stored power.

[0009] However, in a configuration in which the power adjustment of each power converter to reduce the difference in the amount of stored energy is performed in a certain embodiment, it is possible that excessive temperature differences may occur unintentionally among the power converters during the period in which the power adjustment is performed, or that it may take an excessive amount of time for the difference in the amount of stored energy to be sufficiently reduced. For example, if the difference in the output power of each power converter is too large, there is a concern that excessive temperature differences may occur among the power converters. Also, if the difference in the output power of each power converter is too small, there is a concern that it may take an excessive amount of time to reduce the difference in the amount of stored energy.

[0010] In consideration of this, the present disclosure acquires charge / discharge information indicating the charge / discharge state of the storage battery, and changes the mode of power adjustment by each power converter based on the acquired charge / discharge information. This makes it possible to adjust the power of each power converter while taking into account the charge / discharge state of the storage battery, so as to prevent problems such as excessive temperature differences between the power converters and excessive time required to reduce the difference in power storage amount. As a result, a power supply system can be appropriately realized in which each power converter supplies power to an electrical load.

[0011] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. 1 is a diagram showing an example of the operation of the power supply system according to the first embodiment; FIG. 2 is a time chart showing an example of the operation of adjustment control; FIG. 3 is a flowchart showing the processing procedure of adjustment control; FIG. 4 is a diagram showing an example of a method for setting an increase and a decrease; FIG. 5 is a flowchart showing the processing procedure of adjustment control according to a modified example of the first embodiment; FIG. 6 is a diagram showing an example of a method for setting a difference threshold;

[0012] Several embodiments will be described with reference to the drawings. In several embodiments, functionally and / or structurally corresponding and / or associated parts may be designated by the same reference numerals or reference numerals that differ in the hundredth or more digit. For corresponding and / or associated parts, reference may be made to the descriptions of other embodiments.

[0013] First Embodiment A first embodiment of a control device according to the present disclosure will now be described with reference to the drawings. In this embodiment, the control device is applied to an on-board power supply system. The power supply system is mounted on an electric vehicle that uses a motor as a driving power source.

[0014] As shown in FIG. 1 , the power supply system 10 includes a high-voltage storage battery 11 and a high-voltage load 12. The high-voltage storage battery 11 is a battery pack including a plurality of unit cells connected in series. The unit cell is a single battery cell or a plurality of unit cells connected in series. The battery cell is, for example, a secondary battery such as a lithium-ion battery. The rated voltage of the high-voltage storage battery 11 is, for example, several hundred volts. Both ends of the high-voltage storage battery 11 are connected to the high-voltage load 12.

[0015] In this embodiment, the high-voltage load 12 is a three-phase inverter 13 and a rotating electric machine 14. The rotating electric machine 14 has armature windings electrically connected to the inverter 13, the number of which corresponds to the number of phases. The inverter 13 controls the current flowing through the windings of each phase. The rotating electric machine 14 is an on-board main motor, and a rotor of the rotating electric machine 14 is capable of transmitting power to the drive wheels of the vehicle. The rotating electric machine 14 is, for example, a permanent magnet synchronous machine.

[0016] The inverter 13 converts DC power supplied from the high-voltage storage battery 11 into AC power and supplies the power to each phase winding of the rotating electric machine 14. In this case, the rotating electric machine 14 serves as a power source for running the vehicle. The rotating electric machine 14 also generates regenerative power using the rotational force applied to the rotor. The inverter 13 converts the generated AC power into DC power and outputs the power to the high-voltage storage battery 11.

[0017] The power supply system 10 includes a low-voltage load 20 and a power converter 21. The low-voltage load 20 is connected to the high-voltage storage battery 11 via the power converter 21. The power converter 21 is a DC-DC converter that steps down the voltage of the high-voltage storage battery 11 and supplies the stepped-down voltage to the low-voltage load 20. For example, an isolated DC-DC converter can be used as the power converter 21.

[0018] In the power supply system 10 , it is possible to redundantly supply power from the high-voltage storage battery 11 to the low-voltage load 20 .

[0019] Specifically, among the unit batteries that make up the high-voltage storage battery 11, some of the unit batteries make up a first battery group 11A, and the remaining unit batteries make up a second battery group 11B. In other words, the high-voltage storage battery 11 is divided into two blocks. In the series-connected assembly of the first battery group 11A and the second battery group 11B, the first battery group 11A is on the high-potential side, and the second battery group 11B is on the low-potential side. In this embodiment, the number of unit batteries that make up the first battery group 11A is the same as the number of unit batteries that make up the second battery group 11B. Therefore, the voltage (e.g., rated voltage) of the first battery group 11A is the same as the voltage (e.g., rated voltage) of the second battery group 11B.

[0020] The power supply system 10 is provided with two power converters 21, which are connected to both ends of each of the battery groups 11A and 11B. Hereinafter, the power converter 21A connected to both ends of the first battery group 11A may be referred to as the "first power converter 21A," and the power converter 21B connected to both ends of the second battery group 11B may be referred to as the "second power converter 21B."

[0021] The positive terminal of the first battery group 11A is connected to the first power converter 21A. The negative terminal of the first battery group 11A and the positive terminal of the second battery group 11B are connected to the power converters 21A and 21B, respectively. The negative terminal of the second battery group 11B is connected to the second power converter 21B.

[0022] The low-voltage load 20 includes a low-voltage battery 22, a normal auxiliary device 23, and a protective auxiliary device 24. The rated voltage of the low-voltage battery 22 is lower than that of the high-voltage battery 11, for example, 12 V. The low-voltage battery 22 is a rechargeable battery, for example, a lead-acid battery or a lithium-ion battery.

[0023] The normal auxiliary devices 23 and the protective auxiliary devices 24 are electrical loads that operate by receiving power from the low-voltage storage battery 22 and the power converters 21A and 21B. For example, the normal auxiliary devices 23 are general electrical loads, such as an air conditioner, an audio system, power windows, an electric fan for a radiator that cools engine coolant, a stop lamp, an interior light, a USB power socket, and a motor that drives a mirror provided outside the vehicle. For example, the protective auxiliary devices 24 are electrical loads used for vehicle driving assistance control, such as an electric power steering device that generates an assist torque to assist the driver's steering, an electric brake device that applies braking force to the wheels, a camera for monitoring the conditions around the vehicle, a laser radar such as LIDAR (Laser Imaging Detection and Ranging), a millimeter-wave radar, a by-wire system, etc.

[0024] The power supply system 10 includes first to fifth electrical paths 31 to 35 and a connection switch 36 .

[0025] The first power converter 21A is connected to the positive electrode side of the normal auxiliary device 23 via a first electrical path 31. The positive electrode side of the protective auxiliary device 24 is connected to the first electrical path 31 via a second electrical path 32. The positive electrode side of the low-voltage storage battery 22 is connected to the first electrical path 31 via a third electrical path 33. The negative electrode side of the low-voltage storage battery 22, the negative electrode side of the normal auxiliary device 23, and the negative electrode side of the protective auxiliary device 24 are connected to a grounding portion. This makes it possible to supply power from the first power converter 21A to the low-voltage storage battery 22, the normal auxiliary device 23, and the protective auxiliary device 24.

[0026] The second power converter 21B is connected to the first electrical path 31 via the fourth electrical path 34. In a state in which the second power converter 21B is connected to the first electrical path 31 via the fourth electrical path 34, power is supplied to the low voltage load 20 in parallel from both the power converters 21A and 21B.

[0027] The positive electrode side of the protective auxiliary device 24 is connected to the fourth electrical path 34 via a fifth electrical path 35, which is a path separate from the second electrical path 32. A connection switch 36 is provided in the fourth electrical path 34 between a connection point with the first electrical path 31 and a connection point with the fifth electrical path 35. The connection switch 36 is a relay or a semiconductor switching element. The connection switch 36 is controlled by a control device 40 provided in the power supply system 10. In this case, even if power supply from one of the power converters 21A, 21B to the protective auxiliary device 24 becomes impossible, power supply from the other power converter to the protective auxiliary device 24 can continue.

[0028] For example, when no abnormality occurs in the power supply system 10, the control device 40 keeps the connection switch 36 on. This allows power to be supplied in parallel from the power converters 21A, 21B to the low-voltage storage battery 22, the normal auxiliary device 23, and the protective auxiliary device 24. On the other hand, when at least one of the first power converter 21A, the first electrical path 31, and the second electrical path 32 fails, the control device 40 turns the connection switch 36 off. In this case, power can continue to be supplied from the second power converter 21B to the protective auxiliary device 24 via the fourth and fifth electrical paths 34, 35.

[0029] The power supply system 10 includes a voltage sensor 50 and a current sensor 51. The voltage sensor 50 detects the voltage of each unit battery that constitutes the high-voltage storage battery 11. The current sensor 51 detects the current flowing through the high-voltage storage battery 11. The detected values ​​of the sensors 50 and 51 are input to the control device 40.

[0030] The control device 40 is an electronic control unit (ECU) that performs various controls of the power supply system 10, and includes a processor and a storage unit as hardware. Note that in the power supply system 10, each device can be controlled by an ECU corresponding to the inverter 13, each power converter 21A, 21B, and auxiliary protection device 24. However, for convenience, multiple ECUs are shown as a single control device 40 in FIG. 1 .

[0031] The memory unit of the control device 40 includes a memory and a storage as hardware. The memory is a storage device for storing data used in the processing of the control device 40. The memory provides the processor with a working area for temporary use when the processor performs processing, for example. The memory includes, for example, a ROM or a RAM. The storage is a storage device for storing various programs and data to be read and executed by the processor, and is a non-transitory tangible storage medium. The storage includes, for example, an HDD or a flash memory. The storage stores program information and the like for processing, such as those shown in Figures 3, 5, 12, 15, and 16, which will be described later.

[0032] For example, program information stored in a non-transient physical recording medium is installed in the storage unit of the control device 40. The recording medium is, for example, a USB memory, a CD-ROM, or a DVD. Also, for example, program information transmitted via a communication network, such as over the air (OTA), is installed in the storage unit.

[0033] When power is redundantly supplied from each of the battery groups 11A, 11B to the low-voltage load 20, it is conceivable that a difference will occur in the SOC (corresponding to the "amount of stored electricity") between the battery groups 11A, 11B. Therefore, the control device 40 performs adjustment control to adjust the output power of each of the power converters 21A, 21B in order to reduce the difference in SOC between the battery groups 11A, 11B.

[0034] In the present embodiment, the control device 40 controls the switching of the power converters 21A, 21B to step down the voltage of the high-voltage storage battery 11 and output the stepped-down voltage to the low-voltage load 20.

[0035] The control device 40 includes a first SOC calculation unit 41, a second SOC calculation unit 42, a difference calculation unit 43, and an adjustment unit 44. The first SOC calculation unit 41 calculates the SOC of the first battery group 11A. The second SOC calculation unit 42 calculates the SOC of the second battery group 11B. The first calculated value SOC1r calculated by the first SOC calculation unit 41 and the second calculated value SOC2r calculated by the second SOC calculation unit 42 are input to the difference calculation unit 43.

[0036] For example, each SOC calculation unit 41, 42 can calculate the corresponding calculated value SOC1r, SOC2r based on the detected values ​​of the voltage sensor 50 and the current sensor 51. In this case, each SOC calculation unit 41, 42 may calculate the SOC of each of the plurality of unit batteries constituting the high-voltage storage battery 11. The first SOC calculation unit 41 may calculate the maximum, minimum, average, or the like of the SOC of each of the plurality of unit batteries constituting the first battery group 11A as the SOC of the first battery group 11A. The second SOC calculation unit 42 may calculate the maximum, minimum, average, or the like of the SOC of each of the plurality of unit batteries constituting the second battery group 11B as the SOC of the second battery group 11B.

[0037] The difference calculation unit 43 calculates the difference in the amount of stored electricity ΔSOC, which is the difference between the input calculated values ​​SOC1r and SOC2r. The calculated difference in the amount of stored electricity ΔSOC is input to the adjustment unit 44. The difference in the amount of stored electricity ΔSOC is calculated as the absolute value of the difference between the calculated values ​​SOC1r and SOC2r.

[0038] The adjustment unit 44 determines whether the input difference in the amount of stored power ΔSOC is greater than a predetermined difference threshold TH. When the adjustment unit 44 determines that the input difference in the amount of stored power ΔSOC is greater than the predetermined difference threshold TH, the adjustment unit 44 adjusts the output power of each of the power converters 21A, 21B.

[0039] Specifically, when the first calculated value SOC1r is lower than the second calculated value SOC2r, for example, during discharge of the high-voltage storage battery 11, the adjustment unit 44 adjusts the output power of each of the power converters 21A, 21B so that the power output from the second battery group 11B is higher than that of the first battery group 11A. This makes the degree of decrease in the SOC of the first battery group 11A smaller than the degree of decrease in the SOC of the second battery group 11B, thereby reducing the SOC difference between the battery groups 11A, 11B.

[0040] For example, when the second calculated value SOC2r is lower than the first calculated value SOC1r during discharge of the high-voltage storage battery 11, the adjustment unit 44 adjusts the output power of each of the power converters 21A, 21B so that the power output from the first battery group 11A is higher than that of the second battery group 11B. This makes the degree of decrease in the SOC of the second battery group 11B smaller than the degree of decrease in the SOC of the first battery group 11A, and can reduce the difference in the amount of stored electricity ΔSOC between the battery groups 11A, 11B.

[0041] However, if the output power of each power converter 21A, 21B is not adjusted appropriately, there is a concern that the power supply system 10 that supplies power from each power converter 21A, 21B to the low voltage load 20 may not be properly realized.

[0042] Specifically, the adjustment control operation will be described with reference to an example shown in Fig. 2. In Fig. 2, (a) shows the transition of the output voltage of each power converter 21A, 21B, (b) shows the transition of the supply current supplied to the low-voltage load 20, and (c) shows the transition of the first calculated value SOC1r and the second calculated value SOC2r. Fig. 2 assumes a situation in which the high-voltage storage battery 11 is discharged to supply power to the high-voltage load 12 and the low-voltage load 20.

[0043] At time t1, the adjustment unit 44 sets the output voltage of the first power converter 21A to a reference voltage V1r, and sets the output voltage of the second power converter 21B to a reference voltage V2r. Each of the reference voltages V1r, V2r is, for example, a voltage equal to or lower than the rated voltage of each of the power converters 21A, 21B. Here, each of the reference voltages V1r, V2r has the same value, for example, 13.8 V. Note that each of the reference voltages V1r, V2r may also have different values.

[0044] After time t1, each power converter 21A, 21B supplies the low-voltage load 20 with a requested current Ib. Fig. 2(b) shows the breakdown of the requested current Ib, which is made up of a first supply current Ib1 supplied from the first power converter 21A to the low-voltage load 20 and a second supply current Ib2 supplied from the second power converter 21B to the low-voltage load 20.

[0045] During the period from time t1 to time t2, because the second supply current Ib2 is smaller than the first supply current Ib1, the rate of decrease in the SOC of the second battery group 11B is smaller than the rate of decrease in the SOC of the first battery group 11A. In this case, the calculated values ​​SOC1r and SOC2r change so that the second calculated value SOC2r exceeds the first calculated value SOC1r and the difference between the calculated values ​​SOC1r and SOC2r gradually increases.

[0046] In this embodiment, the supply currents Ib1 and Ib2 are different because there is a difference in the path resistance of the electrical path between the low voltage load 20 and the power converters 21A and 21B. In this case, even if the output voltages of the power converters 21A and 21B are set to the same value, a difference occurs between the supply currents Ib1 and Ib2.

[0047] 1 , the second power converter 21B is connected to the first electrical path 31 via the fourth electrical path 34. In this case, the path length of the electrical path from the second power converter 21B to the low-voltage load 20 is longer than the path length of the electrical path from the first power converter 21A to the low-voltage load 20. Accordingly, the path resistance of the electrical path from the second power converter 21B to the low-voltage load 20 is greater than the path resistance of the electrical path from the first power converter 21A to the low-voltage load 20.

[0048] At time t2, the adjustment unit 44 determines that the charge amount difference ΔSOC is greater than the difference threshold TH and that the first calculated value SOC1r is lower than the second calculated value SOC2r. In this case, the adjustment unit 44 adjusts the output power of each power converter 21A, 21B so that the degree of decrease in the SOC of the first battery group 11A is smaller than the degree of decrease in the SOC of the second battery group 11B. In this embodiment, the adjustment unit 44 adjusts the output voltage of each power converter 21A, 21B during adjustment control to adjust the output power of each power converter 21A, 21B. Specifically, the adjustment unit 44 reduces the output voltage of the first power converter 21A by a reduction amount Vβ and increases the output voltage of the second power converter 21B by an increase amount Vα. As a result, the first supply current Ib1 is reduced and the second supply current Ib2 is increased, making the first supply current Ib1 smaller than the second supply current Ib2.

[0049] During the period from time t2 to time t3, the difference in the amount of stored energy ΔSOC between the calculated values ​​SOC1r and SOC2r gradually decreases. At time t3, the difference in the amount of stored energy ΔSOC between the battery groups 11A and 11B becomes sufficiently small. In this case, the adjustment unit 44 sets the output voltages of the power converters 21A and 21B to the reference voltages V1r and V2r again. This reduces the difference in output power between the power converters 21A and 21B, and prevents a temperature difference from occurring between the power converters 21A and 21B.

[0050] However, in a configuration in which adjustment control is performed in a certain embodiment, it is conceivable that an excessive temperature difference may occur between the power converters 21A and 21B unintentionally during the period in which power adjustment is performed, or that it may take an excessive amount of time for the storage amount difference ΔSOC to become sufficiently small. For example, if the difference in output power between the power converters 21A and 21B is too large, there is a concern that an excessive temperature difference may occur between the power converters 21A and 21B. Furthermore, if the difference in output power between the power converters 21A and 21B is too small, there is a concern that it may take an excessive amount of time to reduce the storage amount difference ΔSOC.

[0051] Therefore, in this embodiment, the mode of adjustment control is changed depending on the charge / discharge state of the high-voltage storage battery 11. A configuration for changing the mode of adjustment control will be described below.

[0052] Returning to the explanation of FIG. 1 , the control device 40 includes an acquisition unit 45. The acquisition unit 45 acquires charge / discharge information indicating the charge / discharge state of the high-voltage storage battery 11. The adjustment unit 44 changes the implementation of adjustment control based on the acquired charge / discharge information. In this embodiment, the charge / discharge information is information related to the charge / discharge power in the charge / discharge state of the high-voltage storage battery 11, specifically, the power Pa required by the high-voltage load 12 and the power Pb required by the low-voltage load 20. The higher the power Pa and Pb required by each load 12 and 20, the higher the charge / discharge power of the high-voltage storage battery 11.

[0053] When the charge / discharge power of the high-voltage storage battery 11 is high, the period until the SOC of one of the battery groups 11A, 11B reaches the upper limit or the lower limit is shorter than when the charge / discharge power of the high-voltage storage battery 11 is low. Therefore, when the charge / discharge power of the high-voltage storage battery 11 is high, it is desirable to quickly reduce the difference in the amount of stored electricity ΔSOC between the battery groups 11A, 11B in order to ensure appropriate use of the high-voltage storage battery 11.

[0054] When the charge / discharge power of the high-voltage storage battery 11 indicated by the acquired charge / discharge information is greater than the charge / discharge power threshold, the adjustment unit 44 sets a larger power adjustment amount of each power converter 21A, 21B to reduce the storage amount difference ΔSOC compared to when the charge / discharge power of the high-voltage storage battery 11 is equal to or less than the charge / discharge power threshold. In this embodiment, the adjustment unit 44 increases the power adjustment amount of each power converter 21A, 21B by setting the increase Vα and decrease Vβ of the output voltage of each power converter 21A, 21B to larger values.

[0055] 3 shows the procedure of the adjustment control performed by the control device 40. This control is repeatedly executed by the processor of the control device 40 at predetermined intervals.

[0056] In step S10, charge / discharge information is acquired by the acquisition unit 45. In step S11, the first SOC calculation unit 41 calculates a first calculated value SOC1r. In step S12, the second SOC calculation unit 42 calculates a second calculated value SOC2r.

[0057] In step S13, the difference calculation unit 43 calculates the charge amount difference ΔSOC based on the calculated values ​​SOC1r and SOC2r. Then, the adjustment unit 44 determines whether the calculated charge amount difference ΔSOC is smaller than the difference threshold value TH.

[0058] If the determination in step S13 is affirmative, the process proceeds to step S14. In step S14, the adjustment unit 44 sets the output voltage of the first power converter 21A to a reference voltage V1r. In step S15, the adjustment unit 44 sets the output voltage of the second power converter 21B to a reference voltage V2r. In this embodiment, the reference voltages V1r and V2r are set to the same value.

[0059] If the determination in step S13 is negative, the process proceeds to step S16. In step S16, the adjustment unit 44 determines whether the first calculated value SOC1r is higher than the second calculated value SOC2r. If it is determined that the first calculated value SOC1r is higher than the second calculated value SOC2r, the process proceeds to steps S17 to S19. On the other hand, if it is determined that the first calculated value SOC1r is lower than the second calculated value SOC2r, the process proceeds to steps S20 to S22.

[0060] In step S17, the adjusting unit 44 sets an increase Vα in the output voltage of the first power converter 21A and a decrease Vβ in the output voltage of the second power converter 21B based on the acquired charge / discharge information.

[0061] FIG. 4 shows an example of a method for setting the increase amount Vα and the decrease amount Vβ. Here, the adjustment unit 44 sets the increase amount Vα and the decrease amount Vβ based on the total power Pa+Pb of the required powers Pa and Pb of the loads 12 and 20. When the total power Pa+Pb is equal to or less than a low power threshold PL set as a charge / discharge power threshold, the adjustment unit 44 sets the increase amount Vα and the decrease amount Vβ to a low adjustment voltage value VL. When the total power Pa+Pb is higher than a high power threshold PH set on the high power side relative to the low power threshold PL, the adjustment unit 44 sets the increase amount Vα and the decrease amount Vβ to a high adjustment voltage value VH. The high adjustment voltage value VH is a value higher than the low adjustment voltage value VL. When the total power Pa+Pb is higher than the low power threshold PL and equal to or less than the high power threshold PH, the adjustment unit 44 sets the increase amount Vα and the decrease amount Vβ higher as the total power Pa+Pb increases.

[0062] The adjustment unit 44 can set the increase Vα and decrease Vβ to the same value or different values. For example, the adjustment unit 44 can set the value of only one of the increase Vα and decrease Vβ by the setting method described in FIG. 4, and set the value of the other to 0.

[0063] In step S18, the adjustment unit 44 sets the output voltage of the first power converter 21A to a value obtained by adding the increase amount Vα to the reference voltage V1r. In step S19, the adjustment unit 44 sets the output voltage of the second power converter 21B to a value obtained by subtracting the decrease amount Vβ from the reference voltage V2r.

[0064] In step S20, the adjustment unit 44 sets an increase Vα in the output voltage of the second power converter 21B and a decrease Vβ in the output voltage of the first power converter 21A based on the acquired charge / discharge information. The method for setting the increase Vα and decrease Vβ is the same as the method described in step S17.

[0065] In step S21, the adjustment unit 44 sets the output voltage of the first power converter 21A to a value obtained by subtracting the decrease Vβ from the reference voltage V1r. In step S22, the adjustment unit 44 sets the output voltage of the second power converter 21B to a value obtained by adding the increase Vα to the reference voltage V2r.

[0066] According to the present embodiment described above in detail, the following effects can be obtained.

[0067] In this embodiment, charge / discharge information indicating the charge / discharge state of the high-voltage storage battery 11 is acquired, and the implementation of the adjustment control is changed based on the acquired charge / discharge information. This makes it possible to adjust the power of each power converter 21A, 21B in consideration of the charge / discharge state of the high-voltage storage battery 11 so as to prevent problems such as an excessive temperature difference between the power converters 21A, 21B and excessive time required to reduce the charge storage amount difference ΔSOC. As a result, it is possible to appropriately realize the power supply system 10 that supplies power from each power converter 21A, 21B to the low-voltage load 20.

[0068] When the charge / discharge power of the high-voltage battery 11 indicated by the charge / discharge information is greater than the charge / discharge power threshold, the power adjustment amount of each power converter 21A, 21B is set to be larger than when the charge / discharge power of the high-voltage battery 11 is equal to or less than the charge / discharge power threshold. By adjusting the power of each power converter 21A, 21B based on the set power adjustment amount, the charge / discharge power difference ΔSOC can be quickly reduced. As a result, a configuration suitable for ensuring appropriate use of the high-voltage battery 11 can be realized when the charge / discharge power of the high-voltage battery 11 is large.

[0069] The mode of adjustment control is changed by changing the output voltage of each power converter 21A, 21B. In this case, the output voltage of one of the power converters 21A, 21B is increased and the output voltage of the other power converter is decreased based on the charge / discharge information, thereby enabling accurate adjustment of the output power of each power converter 21A, 21B. Therefore, a configuration suitable for adjusting the power of each power converter 21A, 21B can be realized.

[0070] Modification of First Embodiment The adjustment unit 44 may change the mode of adjustment control by variably setting the difference threshold TH based on the acquired charge / discharge information.

[0071] 5, after the process of step S12, the process proceeds to step S30. In step S30, the adjustment unit 44 sets the difference threshold value TH based on the acquired charge / discharge information. A method for setting the difference threshold value TH will be described below.

[0072] In a situation where the charge / discharge power of the high-voltage battery 11 is high, it is desirable to adjust the power of each power converter 21A, 21B as soon as possible after the occurrence of the storage amount difference ΔSOC in order to ensure appropriate use of the high-voltage battery 11. Therefore, when the charge / discharge power of the high-voltage battery 11 indicated by the acquired charge / discharge information is greater than the charge / discharge power threshold, the adjustment unit 44 sets the difference threshold TH to a smaller value than when the charge / discharge power of the high-voltage battery 11 is equal to or less than the charge / discharge power threshold.

[0073] 6 shows an example of a method for setting the difference threshold TH. Here, the adjustment unit 44 sets the difference threshold TH based on the total power Pa+Pb of the required powers Pa and Pb of the loads 12 and 20. When the total power Pa+Pb is equal to or less than the low power threshold PL, the adjustment unit 44 sets the difference threshold TH to a first threshold TH1. When the total power Pa+Pb is higher than the high power threshold PH, the adjustment unit 44 sets the difference threshold TH to a second threshold TH2. The second threshold TH2 is a smaller value than the first threshold TH1. When the total power Pa+Pb is higher than the low power threshold PL and equal to or less than the high power threshold PH, the adjustment unit 44 sets the difference threshold TH to a smaller value as the total power Pa+Pb increases.

[0074] In this embodiment, when the charge / discharge power of the high-voltage battery 11 indicated by the charge / discharge information is greater than the charge / discharge power threshold, the difference threshold TH for determining whether to adjust the power of each power converter 21A, 21B is set to a smaller value than when the charge / discharge power of the high-voltage battery 11 is equal to or less than the charge / discharge power threshold. This allows the power adjustment of each power converter 21A, 21B to be started earlier than when a larger difference threshold TH is set. This prevents the charge amount difference ΔSOC from becoming large. As a result, a configuration suitable for ensuring appropriate use of the high-voltage battery 11 in situations where the charge / discharge power of the high-voltage battery 11 is large can be realized.

[0075] On the other hand, when the charge / discharge power of the high-voltage storage battery 11 indicated by the charge / discharge information is equal to or less than the charge / discharge power threshold, the difference threshold TH is set to a larger value than when the charge / discharge power of the high-voltage storage battery 11 is greater than the charge / discharge threshold. This makes it possible to prevent adjustment control from being performed frequently when the charge / discharge power of the high-voltage storage battery 11 is small, and to prevent an excessive temperature difference from occurring between the power converters 21A, 21B.

[0076] 5, the processes of steps S17 and S20 may not be performed. In this case, predetermined values ​​may be used as the increase amount Vα and the decrease amount Vβ in steps S18, S19, S21, and S22.

[0077] The acquisition unit 45 may acquire, as the charge / discharge information, either one of the required powers Pa and Pb of the loads 12 and 20. Even in this case, the adjustment unit 44 can perform the process of setting the increase Vα, decrease Vβ, and difference threshold TH described above with reference to FIGS.

[0078] The acquisition unit 45 may acquire information other than the required powers Pa and Pb of the loads 12 and 20 as the charge / discharge information.

[0079] For example, the acquisition unit 45 may acquire, as the charge / discharge information, high-voltage discharge information indicating that power is being supplied to the high-voltage load 12. Specifically, the high-voltage discharge information is information indicating that the rotating electric machine 14 is being driven, such as information such as the command torque of the rotating electric machine 14 or the accelerator operation amount of the accelerator pedal operated by the user. When the high-voltage discharge information is acquired, the adjustment unit 44 may change the mode of adjustment control by performing a process to set the increase amount Vα and the decrease amount Vβ to higher values ​​than when the high-voltage discharge information is not acquired. Furthermore, when the high-voltage discharge information is acquired, the adjustment unit 44 may change the mode of adjustment control by performing a process to set the difference threshold TH to a lower value than when the high-voltage discharge information is not acquired. Even in this case, the adjustment unit 44 can perform adjustment control based on the acquired high-voltage discharge information, taking into account the fact that the discharge power of the high-voltage storage battery 11 is high due to the drive of the rotating electric machine 14.

[0080] For example, the acquisition unit 45 may acquire, as the charge / discharge information, charging information indicating that there is a request to charge the high-voltage storage battery 11 by an external charger. The adjustment unit 44 may change the mode of adjustment control by performing a process to set the increase amount Vα and the decrease amount Vβ to higher values ​​when the charging information is acquired compared to when the charging information is not acquired. Furthermore, the adjustment unit 44 may change the mode of adjustment control by performing a process to set the difference threshold TH to a lower value when the charging information is acquired compared to when the charging information is not acquired. Even in this case, the adjustment unit 44 can perform adjustment control based on the acquired charging information, taking into account the fact that the charging power of the high-voltage storage battery 11 is high due to the use of the external charger.

[0081] For example, the acquisition unit 45 may acquire the amount of change over time of each calculated value SOC1r, SOCr as the charge / discharge information. The adjustment unit 44 may change the mode of adjustment control by performing a process of setting the increase amount Vα and the decrease amount Vβ to higher values ​​when the acquired amount of change over time of each calculated value SOC1r, SOCr is large compared to when the amount of change over time of each calculated value SOC1r, SOCr is small. Furthermore, the adjustment unit 44 may change the mode of adjustment control by performing a process of setting the difference threshold TH to a lower value when the acquired amount of change over time of each calculated value SOC1r, SOCr is large compared to when the amount of change over time of each calculated value SOC1r, SOCr is small. Even in this case, the adjustment unit 44 can perform adjustment control based on the acquired charge / discharge information, taking into account the fact that the charge / discharge power of the high-voltage storage battery 11 is high.

[0082] Second Embodiment A second embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, the charge / discharge information acquired by the acquisition unit 45 is changed.

[0083] There is a concern that one of the calculated values ​​SOC1r, SOC2r of each of the battery groups 11A, 11B during discharging will reach the discharge lower limit SOCL, limiting the discharge of the high-voltage storage battery 11. Therefore, in a situation where the calculated values ​​SOC1r, SOC2r of each of the battery groups 11A, 11B during discharging are close to the discharge lower limit SOCL, it is desirable to quickly reduce the storage amount difference ΔSOC of each of the battery groups 11A, 11B in order to continue using the high-voltage storage battery 11 as long as possible.

[0084] 5 , the acquisition unit 45 acquires, as charge / discharge information, a discharge margin Md (see FIG. 7 ), which is the margin of SOC relative to the discharge lower limit SOCL of the high-voltage battery 11, instead of the charge / discharge power of the high-voltage battery 11. In steps S17 and S20, the adjustment unit 44 sets the increase Vα and decrease Vβ for reducing the storage amount difference ΔSOC to larger values ​​when the acquired discharge margin Md is less than a predetermined value, compared to when the discharge margin Md is equal to or greater than the predetermined value. Furthermore, in step S30, the adjustment unit 44 sets the difference threshold TH to a smaller value when the acquired discharge margin Md is less than the predetermined value, compared to when the discharge margin Md is equal to or greater than the predetermined value.

[0085] 8 shows an example of a method for setting the increase amount Vα and the decrease amount Vβ based on the discharge margin Md. When the discharge margin Md is greater than a first predetermined value M1, the adjustment unit 44 sets the increase amount Vα and the decrease amount Vβ to the low regulated voltage value VL. When the discharge margin Md is equal to or less than a second predetermined value M2, the adjustment unit 44 sets the increase amount Vα and the decrease amount Vβ to the high regulated voltage value VH. The second predetermined value M2 is a value smaller than the first predetermined value M1. When the discharge margin Md is equal to or less than the first predetermined value M1 and greater than the second predetermined value M2, the adjustment unit 44 sets the increase amount Vα and the decrease amount Vβ higher as the discharge margin Md becomes smaller.

[0086] 9 shows an example of a method for setting the difference threshold TH based on the discharge margin Md. When the discharge margin Md is greater than a first predetermined value M1, the adjustment unit 44 sets the difference threshold TH to a first threshold TH1. When the discharge margin Md is equal to or less than a second predetermined value M2, the adjustment unit 44 sets the difference threshold TH to a second threshold TH2. When the discharge margin Md is equal to or less than the first predetermined value M1 and greater than the second predetermined value M2, the adjustment unit 44 sets the difference threshold TH to a smaller value as the discharge margin Md decreases.

[0087] By adjusting the power of each power converter 21A, 21B based on the set power adjustment amount, it is possible to shorten the time required to reduce the charge storage amount difference ΔSOC when the SOC of each battery group 11A, 11B is close to the discharge lower limit SOCL. As a result, it is possible to realize a configuration that is suitable for continuing use of the high-voltage battery 11 as long as possible when the SOC of the high-voltage battery 11 during discharging is close to the discharge lower limit SOCL.

[0088] The discharge margin Md as charge / discharge information will be further described with reference to Fig. 7. (a) to (c) of Fig. 7 correspond to (a) to (c) of Fig. 2.

[0089] In this embodiment, the acquisition unit 45 acquires, as the discharge margin Md, the margin relative to the discharge lower limit SOCL of a unit battery having the smallest SOC among the plurality of unit batteries constituting the high-voltage storage battery 11. Note that, for convenience of explanation, Fig. 7(c) shows the SOC transitions of two unit batteries among the plurality of unit batteries in each of the battery groups 11A and 11B. In Fig. 7, X represents the smallest SOC among the plurality of unit batteries constituting the high-voltage storage battery 11.

[0090] The adjustment unit 44 changes the mode of adjustment control based on the discharge margin Md, which is the difference between the minimum SOC of the acquired SOCs for each of the plurality of unit batteries and the discharge lower limit SOCL. This makes it possible to adjust the power of each of the power converters 21A, 21B in consideration of the SOC of the unit battery that will reach the discharge lower limit SOCL earliest among the plurality of unit batteries constituting the high-voltage storage battery 11 during discharging. This makes it possible to realize a configuration that is suitable for continuing use of the high-voltage storage battery 11 as long as possible.

[0091] Third Embodiment A third embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, the charge / discharge information acquired by the acquisition unit 45 is changed.

[0092] There is a concern that one of the calculated values ​​SOC1r, SOC2r of each battery group 11A, 11B during charging will reach the charging upper limit value SOCH, restricting the charging of the high-voltage storage battery 11. Therefore, in order to properly charge the high-voltage storage battery 11, it is desirable to quickly reduce the storage amount difference ΔSOC of each battery group 11A, 11B when the calculated values ​​SOC1r, SOC2r of each battery group 11A, 11B during charging are close to the charging upper limit value SOCH.

[0093] 5 , the acquisition unit 45 acquires, as charge / discharge information, a charge margin Mc (see FIG. 10 ), which is the SOC margin relative to the charge upper limit value SOCH of the high-voltage battery 11, instead of the charge / discharge power of the high-voltage battery 11. In steps S17 and S20, the adjustment unit 44 sets the increase Vα and decrease Vβ for reducing the charge amount difference ΔSOC to larger values ​​when the acquired charge margin Mc is less than a predetermined value, compared to when the charge margin Mc is equal to or greater than the predetermined value. Also, in step S30, the adjustment unit 44 sets the difference threshold TH to a smaller value when the acquired charge margin Mc is less than the predetermined value, compared to when the charge margin Mc is equal to or greater than the predetermined value.

[0094] The high-voltage battery 11 may be charged in two ways: when electric power generated by regenerative power generation of the rotating electric machine 14 is supplied to the high-voltage battery 11 via the inverter 13; or when the high-voltage battery 11 is charged by an external charger. The external charger may be, for example, a stationary charger provided outside the vehicle.

[0095] The adjustment unit 44 can set the increase Vα and decrease Vβ, and set the difference threshold TH, based on the charge margin Mc, as described in Figures 8 and 9 of the second embodiment.

[0096] By adjusting the power of each of the power converters 21A, 21B based on the set power adjustment amount, the charge amount difference ΔSOC can be quickly reduced when the SOC of the high-voltage battery 11 being charged is close to the charge upper limit value SOCH. As a result, the high-voltage battery 11 can be appropriately charged.

[0097] The charge margin Mc as charge / discharge information will be further described with reference to Fig. 10. (a) to (c) of Fig. 10 correspond to (a) to (c) of Fig. 2.

[0098] In this embodiment, the acquisition unit 45 acquires, as the charge margin Mc, the margin relative to the charge upper limit value SOCH of a unit battery having the maximum SOC among the plurality of unit batteries constituting the high-voltage storage battery 11. Note that, for convenience of explanation, Fig. 10(c) illustrates the SOC transitions of two unit batteries among the plurality of unit batteries in each of the battery groups 11A and 11B. In Fig. 10, Y represents the maximum SOC among the plurality of unit batteries constituting the high-voltage storage battery 11.

[0099] The adjustment unit 44 changes the mode of adjustment control based on the charge margin Mc, which is the difference between the maximum SOC of the acquired SOCs for each of the multiple unit batteries and the charge upper limit SOCH. This makes it possible to adjust the power of each of the power converters 21A, 21B in consideration of the SOC of the unit battery that will reach the charge upper limit SOCH earliest among the multiple unit batteries that make up the high-voltage storage battery 11 being charged. This makes it possible to realize a configuration that is suitable for charging the high-voltage storage battery 11 to full charge.

[0100] Other Embodiments The above-described embodiments may be modified as follows.

[0101] Instead of adjusting the output voltage of each power converter 21A, 21B, the adjustment unit 44 may adjust the output power of each power converter 21A, 21B by limiting the output current of one of the power converters 21A, 21B.

[0102] An example of the operation of the adjustment control is shown in Fig. 11. In Fig. 11, (a) shows the transition of the output current Idc1 of the first power converter 21A, and (b) shows the transition of the output current Idc2 of the second power converter 21B. In Fig. 11, (c) and (d) correspond to Fig. 2(b) and (c) above. In Fig. 11, the output current Idc1 of the first power converter 21A is limited, thereby adjusting the output power of each of the power converters 21A and 21B.

[0103] At time t1, the adjuster 44 sets the output current Idc1 of the first power converter 21A to a value equal to or less than the limit current value IL1. The adjuster 44 also sets the output current Idc2 of the second power converter 21B to a value equal to or less than the limit current value IL2. In this case, the adjuster 44 sets the output currents Idc1 and Idc2 so that the sum of the supply currents Ib1 and Ib2 becomes the required current Ib of the low voltage load 20. Note that here, the limit current values ​​IL1 and IL2 are set to, for example, the rated current values ​​of the power converters 21A and 21B.

[0104] In the period from time t1 to time t2, the output current Idc1 of the first power converter 21A is greater than the output current Idc2 of the second power converter 21B. In this case, as in the description of FIG. 2 , the calculated values ​​SOC1r and SOC2r change so that the second calculated value SOC2r exceeds the first calculated value SOC1r and the difference between the calculated values ​​SOC1r and SOC2r gradually increases.

[0105] At time t2, the adjustment unit 44 determines that the charge amount difference ΔSOC is greater than the difference threshold TH and that the first calculation value SOC1r is lower than the second calculation value SOC2r. In this case, the adjustment unit 44 sets a limit current value IL1 of the output current Idc1 of the first power converter 21A based on the charge / discharge information. Here, the adjustment unit 44 sets the limit current value IL1 to a value smaller than the output current Idc1 of the first power converter 21A set at time t1. As a result, from time t2 onwards, the first supply current Ib1 is reduced compared to before time t2. The adjustment unit 44 sets the output current Idc2 of the second power converter 21B to increase by the amount of the reduction in the output current Idc1 of the first power converter 21A. As a result, from time t2 onwards, the second supply current Ib2 is reduced compared to before time t2. The method for setting the limit current value IL1 will be described later.

[0106] During the period from time t2 to time t3, the first supply current Ib1 is made smaller than the second supply current Ib2. As a result, the charge storage difference ΔSOC, which is the difference between the calculated values ​​SOC1r and SOC2r, gradually decreases. At time t3, the difference in SOC between the battery groups 11A and 11B is eliminated. In this case, the adjustment unit 44 sets the limit current value IL1 to the same value as before time t2. This allows the adjustment unit 44 to set the output currents Idc1 and Idc2 of the power converters 21A and 21B to the same values ​​as before time t2.

[0107] Next, the processing procedure of adjustment control will be described. In this embodiment, as shown in FIG. 12 , if a positive determination is made in step S13, the process proceeds to step S40. In step S40, the adjustment unit 44 sets the output current Idc1 of the first power converter 21A. In step S41, the adjustment unit 44 sets the output current Idc1 of the second power converter 21B. The adjustment unit 44 sets the output currents Idc1 and Idc2 so that the sum of the supply currents Ib1 and Ib2 becomes the required current Ib of the low voltage load 20.

[0108] If the determination in step S16 is affirmative, the process proceeds to step S42. In step S42, the adjustment unit 44 sets a limit current value IL2 of the output current Idc2 of the second power converter 21B based on the charge / discharge information.

[0109] 13 shows an example of a method for setting the limit current value IL2 based on the total power Pa+Pb of the required powers Pa and Pb of the loads 12 and 20. When the total power Pa+Pb is equal to or less than the low power threshold PL, the adjuster 44 sets the limit current value IL2 to the first current value ILa. For example, the first current value ILa is a value smaller than the currently set output current Idc2 of the second power converter 21B. When the total power Pa+Pb is higher than the high power threshold PH, the adjuster 44 sets the limit current value IL2 to the second current value ILb. The second current value ILb is a value smaller than the first current value ILa. When the total power Pa+Pb is higher than the low power threshold PL and equal to or less than the high power threshold PH, the adjuster 44 sets the limit current value IL2 to a smaller value as the total power Pa+Pb increases.

[0110] 14 shows an example of a method for setting the limit current value IL2 based on the discharge margin Md described in the second embodiment or the charge margin Mc described in the third embodiment. When the margins Mc, Md are greater than the first predetermined value M1, the adjustment unit 44 sets the limit current value IL2 to the first current value ILa. When the margins Mc, Md are equal to or less than the second predetermined value M2, the adjustment unit 44 sets the limit current value IL2 to the second current value ILb. When the margins Mc, Md are equal to or less than the first predetermined value M1 and greater than the second predetermined value M2, the adjustment unit 44 sets the limit current value IL2 to a smaller value as the margins Mc, Md are smaller.

[0111] 12 , in step S43, the adjustment unit 44 limits the output current Idc2 of the second power converter 21B to a limit current value IL2 or less. In step S44, the adjustment unit 44 sets the output current Idc1 of the first power converter 21A. For example, the output current Idc1 of the first power converter 21A is set to increase by the amount by which the output current Idc2 of the second power converter 21B is reduced.

[0112] If the determination in step S16 is negative, the process proceeds to step S45. In step S45, the adjustment unit 44 sets a limit current value IL1 of the output current Idc1 of the first power converter 21A based on the charge / discharge information. The limit current value IL1 can be set as described above with reference to FIGS.

[0113] In step S46, the adjustment unit 44 limits the output current Idc1 of the first power converter 21A to a value equal to or less than the limit current value IL1. In step S47, the adjustment unit 44 sets the output current Idc2 of the second power converter 21B. For example, the output current Idc2 of the second power converter 21B is set to increase by the amount by which the output current Idc1 of the first power converter 21A is reduced.

[0114] In this embodiment, the mode of adjustment control is changed by changing the output currents Idc1 and Idc2 of the power converters 21A and 21B. In this case, the output current of one of the power converters 21A and 21B is limited based on the charge / discharge information, thereby enabling the output power of each of the power converters 21A and 21B to be appropriately adjusted. Therefore, a configuration suitable for adjusting the power of each of the power converters 21A and 21B can be realized.

[0115] In the second and third embodiments, the same modifications as those in the modified example of the first embodiment may be made. Specifically, the implementation of the adjustment control may be changed by variably setting the difference threshold value TH based on the margins Mc and Md as charge / discharge information.

[0116] The adjustment unit 44 may set the power adjustment amount of each power converter 21A, 21B for reducing the difference in the amount of stored power ΔSOC to a larger value as the difference in the amount of stored power ΔSOC increases. For example, the adjustment unit 44 may set the increase amount Vα and decrease amount Vβ of the output voltage of each power converter 21A, 21B to larger values ​​as the difference in the amount of stored power ΔSOC increases. Furthermore, for example, the adjustment unit 44 may set one of the limit current values ​​IL1, IL2 to a smaller value as the difference in the amount of stored power ΔSOC increases.

[0117] In each of the above embodiments, the adjustment unit 44 performs adjustment control such that each power converter 21A, 21B performs a step-down operation to step down the voltage of the high-voltage storage battery 11 and apply the stepped-down voltage to the low-voltage load 20, but this is not limited to this.

[0118] In the adjustment control, the adjustment unit 44 may change the mode of power adjustment by each of the power converters 21A, 21B so that the battery group with the higher SOC of the first battery group 11A or the second battery group 11B supplies power to the low-voltage load 20 and to the battery group with the lower SOC. In this case, the adjustment unit 44 causes one of the power converters 21A, 21B to perform a step-down operation and the other of the power converters 21A, 21B to perform a step-up operation. The step-up operation is an operation of boosting the voltage of the low-voltage storage battery 22 and applying the boosted voltage to the first battery group 11A or the second battery group 11B.

[0119] FIG. 15 shows the procedure for adjustment control.

[0120] If the determination in step S16 is affirmative, the process proceeds to step S50. In step S50, the adjustment unit 44 causes the first power converter 21A to perform a step-down operation and the second power converter 21B to perform a step-up operation. In this case, the first power converter 21A adjusts the output voltage applied to the low-voltage side of the first power converter 21A so that power is supplied from the first battery group 11A to the low-voltage load 20 and the second power converter 21B. In the second power converter 21B, the output voltage applied to the high-voltage side of the second power converter 21B is adjusted so that power is supplied from the first power converter 21A to the second battery group 11B.

[0121] If the determination in step S16 is negative, the process proceeds to step S51. In step S51, the adjustment unit 44 causes the first power converter 21A to perform a voltage step-up operation and the second power converter 21B to perform a voltage step-down operation. In this case, the second power converter 21B adjusts the output voltage applied to the low-voltage side of the second power converter 21B so that power is supplied from the second battery group 11B to the low-voltage load 20 and the first power converter 21A. In the first power converter 21A, the output voltage applied to the high-voltage side of the first power converter 21A is adjusted so that power is supplied from the second power converter 21B to the first battery group 11A.

[0122] According to this embodiment, the battery group 11A, 11B with the lower SOC can be charged while the battery group 11A, 11B with the higher SOC can be discharged. This allows power to be exchanged between the battery groups 11A, 11B so that the SOCs of the battery groups 11A, 11B approach each other while satisfying the requirements of the low voltage load 20. Therefore, a configuration suitable for equalizing the SOCs of the battery groups 11A, 11B can be realized.

[0123] In the above embodiments, the adjustment unit 44 adjusts the output power of each power converter 21A, 21B to reduce the difference in the amount of stored power ΔSOC during adjustment control. However, this is not limited to this. The adjustment unit 44 may adjust the output power of each power converter 21A, 21B to increase the difference in the amount of stored power ΔSOC. For example, when one of the battery groups 11A, 11B is deteriorated and needs to be replaced at a factory or the like, it may be desirable to prioritize using up the SOC of the deteriorated battery group over the normal battery group. In this case, adjustment control is performed to increase the difference in the amount of stored power ΔSOC.

[0124] Specifically, when the SOC of the second battery group 11B is to be used up preferentially over that of the first battery group 11A, the adjustment unit 44 adjusts the output power of each power converter 21A, 21B so that the power output from the second battery group 11B is higher than that of the first battery group 11A. For example, the adjustment unit 44 sets the output voltage of the second power converter 21B higher than the output voltage of the first power converter 21A. Also, for example, the adjustment unit 44 sets the limit current value IL1 for the output current Idc1 of the first power converter 21A to a value smaller than the limit current value IL2 for the output current Idc2 of the second power converter 21B.

[0125] When the SOC of the first battery group 11A is to be used up preferentially over that of the second battery group 11B, the adjustment unit 44 adjusts the output power of each power converter 21A, 21B so that the power output from the first battery group 11A is higher than that of the second battery group 11B. For example, the adjustment unit 44 sets the output voltage of the first power converter 21A higher than the output voltage of the first power converter 21A. Also, for example, the adjustment unit 44 sets the limit current value IL1 for the output current Idc2 of the second power converter 21B to a value smaller than the limit current value IL1 for the output current Idc1 of the first power converter 21A.

[0126] 16 shows a procedure for adjusting the charge amount difference ΔSOC to be increased. This control is repeatedly executed by the processor of the control device 40 at predetermined intervals.

[0127] In step S60, the same process as in step S11 in Fig. 3 is performed. In step S61, the same process as in step S12 in Fig. 3 is performed.

[0128] In step S62, the difference calculation unit 43 calculates the charge amount difference ΔSOC based on the calculated values ​​SOC1r and SOC2r. Then, the adjustment unit 44 determines whether there is a request to increase the charge amount difference ΔSOC. For example, if there is a request to preferentially use up the SOC of one of the battery groups 11A, 11B, a positive determination is made in step S62. In this case, the process proceeds to step S63. On the other hand, if a negative determination is made in step S62, the control ends.

[0129] In step S63, the adjustment unit 44 determines whether to make the first calculated value SOC1r smaller than the second calculated value SOC2r. For example, if the first battery group 11A is the battery group whose SOC is to be used up preferentially among the battery groups 11A and 11B, a positive determination is made in step S63. On the other hand, if the second battery group 11B is the battery group whose SOC is to be used up preferentially among the battery groups 11A and 11B, a negative determination is made in step S63.

[0130] If the determination in step S63 is affirmative, the process proceeds to step S64. In step S64, the output power of each power converter 21A, 21B is adjusted so that the power output from the first battery group 11A is higher than that of the second battery group 11B.

[0131] If the determination in step S63 is negative, the process proceeds to step S65. In step S65, the output power of each power converter 21A, 21B is adjusted so that the power output from the second battery group 11B is higher than that of the first battery group 11A.

[0132] According to this embodiment, the output power of each power converter 21A, 21B is adjusted so that the charge storage amount difference ΔSOC becomes large. This makes it possible to respond to requests such as preferentially using one of the battery groups 11A, 11B. Therefore, a configuration suitable for appropriate use of the high-voltage storage battery 11 can be realized.

[0133] The high-voltage storage battery 11 is not limited to having two battery groups, but may have three or more battery groups. In this case, a power converter corresponding to each battery group may be connected to both ends of each of the three or more battery groups. Then, for the three or more battery groups, power adjustment of each power converter may be performed based on the power storage amount parameter of each battery group.

[0134] Specifically, for example, in a high-voltage battery 11 having three battery groups, the battery group with the highest SOC (storage capacity parameter) and the battery group with the lowest SOC (storage capacity parameter) are selected from the three battery groups. In this case, these two battery groups correspond to the first and second battery groups. Then, an SOC difference between these two battery groups is calculated, and when the SOC difference exceeds a predetermined threshold, the output power of each power converter is adjusted.

[0135] The adjustment unit 44 may perform adjustment control using a storage amount parameter indicating the storage amount, such as the amount of power and the open circuit voltage (OCV), instead of the SOC of each battery group 11A, 11B.

[0136] The power supply system may be mounted on a vehicle other than a vehicle, and may be mounted on a mobile body such as an aircraft or a ship. If the mobile body is an aircraft, the rotating electric machine serves as the power source for the aircraft's flight, and if the mobile body is a ship, the rotating electric machine serves as the power source for the ship's navigation. Furthermore, the power supply system is not limited to being mounted on a mobile body, and can also be used as a stationary power source.

[0137] The control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described herein may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to perform one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium.

[0138] The technical concepts extracted from the above-described embodiments are described below. [Configuration 1] A power converter control device (40) for use in a power supply system (10) comprising: a storage battery (11) having a first battery group (11A) and a second battery group (11B) connected to each other in series; and a first power converter (21A) and a second power converter (21B) connected to both ends of each battery group, the power converter controlling device (40) comprising: a difference calculation unit (43) calculating a storage amount difference that is a difference between storage amount parameters indicating the storage amounts of the battery groups; an adjustment unit (44) adjusting the output power of each of the power converters when the storage amount difference becomes larger than a predetermined threshold; and an acquisition unit (45) acquiring charge / discharge information indicating a charge / discharge state of the storage batteries, the adjustment unit changing an implementation of power adjustment by each of the power converters based on the acquired charge / discharge information. [Configuration 2] The control device for a power converter according to Configuration 1, wherein the acquisition unit acquires, as the charge / discharge information, information related to charge / discharge power in a charged state or a discharged state of the storage battery, and the adjustment unit changes the embodiment by performing at least one of a process of setting a power adjustment amount of each of the power converters to be larger when the charge / discharge power of the storage battery indicated by the acquired charge / discharge information is large, compared to a case where the charge / discharge power of the storage battery is small, and a process of setting the threshold value to be smaller when the charge / discharge power of the storage battery indicated by the acquired charge / discharge information is large, compared to a case where the charge / discharge power of the storage battery is small.[Configuration 3] The power supply system is capable of supplying power to a low-voltage load as the electrical load and to a high-voltage load to which a higher voltage than the low-voltage load is applied, and power is supplied from each of the battery groups to the low-voltage load via the power converter while power is supplied from the storage battery to the high-voltage load, and the acquisition unit acquires, as the charge / discharge information, high-voltage discharge information indicating that power is being supplied to the high-voltage load when power is being supplied from each of the battery groups to the low-voltage load, and the adjustment unit performs at least one of a process of setting a power adjustment amount of each of the power converters to be larger when the high-voltage discharge information is acquired compared to a case where the high-voltage discharge information is not acquired, and a process of setting the threshold value to be smaller when the high-voltage discharge information is acquired compared to a case where the high-voltage discharge information is not acquired, thereby changing the embodiment. [Configuration 4] The control device for a power converter according to Configuration 1, wherein the acquisition unit acquires, as the charge / discharge information, a discharge margin which is a margin of storage amount of power in the storage battery relative to a lower discharge limit, and the adjustment unit changes the embodiment by performing at least one of a process of setting a power adjustment amount of the power converter to be larger when the acquired discharge margin is less than a predetermined value compared to a case where the discharge margin is greater than or equal to the predetermined value, and a process of setting the threshold value to be smaller when the acquired discharge margin is less than the predetermined value compared to a case where the discharge margin is greater than or equal to the predetermined value. [Configuration 5] The control device for a power converter according to Configuration 4, wherein the acquisition unit acquires, as the discharge margin, a margin of storage amount of power relative to a lower discharge limit of a unit battery with a minimum amount of storage amount among a plurality of unit batteries constituting the storage battery, and the adjustment unit changes the embodiment based on the acquired margin of the unit battery with the minimum amount of storage amount.[Configuration 6] The control device for a power converter according to Configuration 1, wherein the acquisition unit acquires, as the charge / discharge information, a charge margin, which is a margin of storage amount relative to a charge upper limit in the storage battery, and the adjustment unit changes the embodiment by performing at least one of a process of setting a power adjustment amount of each of the power converters to be larger when the acquired charge margin is less than a predetermined value, compared to a process of setting the threshold value smaller when the acquired charge margin is less than the predetermined value, compared to a process of setting the threshold value smaller when the acquired charge margin is less than the predetermined value. [Configuration 7] The control device for a power converter according to Configuration 6, wherein the acquisition unit acquires, as the charge margin, a margin of storage amount relative to a charge upper limit in a unit battery with a maximum stored amount of power among a plurality of unit batteries constituting the storage battery, and the adjustment unit changes the embodiment based on the acquired margin of storage amount of the unit battery with the maximum stored amount. [Configuration 8] The control device for a power converter according to any one of Configurations 2 to 7, wherein the adjustment unit controls the power adjustment amount by changing an output voltage of at least one of the power converters. [Configuration 9] The power converter control device according to Configuration 8, wherein the adjustment unit changes an embodiment of power adjustment by each of the power converters so that power is supplied to the electrical load from the battery group of the first battery group or the second battery group, which has the larger power storage amount parameter, and power is supplied to the battery group of the second battery group, which has the smaller power storage amount parameter. [Configuration 10] The power converter control device according to any one of Configurations 2 to 7, wherein the adjustment unit controls the power adjustment amount by limiting the output current of one of the power converters. [Configuration 11] The power converter control device according to any one of Configurations 1 to 10, wherein the adjustment unit adjusts the output power of each of the power converters so as to increase the power storage amount difference.

[0139] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. A power converter control device (40) applied to a power supply system (10) comprising: a storage battery (11) having a first battery group (11A) and a second battery group (11B) connected in series with each other; and a first power converter (21A) and a second power converter (21B) connected to both ends of each battery group, respectively, and supplying output power after power conversion by each power converter to an electrical load, the power converter control device comprising: a difference calculation unit (43) that calculates a storage amount difference, which is a difference between storage amount parameters that indicate the storage amount of each battery group; an adjustment unit (44) that adjusts the output power of each power converter when the storage amount difference becomes larger than a predetermined threshold; and an acquisition unit (45) that acquires charge / discharge information that indicates the charge / discharge state of the storage battery, and the adjustment unit changes the mode of power adjustment by each power converter based on the acquired charge / discharge information.

2. The control device for a power converter according to claim 1, wherein the acquisition unit acquires, as the charge / discharge information, information related to the charge / discharge power in the charge state or discharge state of the storage battery, and the adjustment unit changes the implementation by performing at least one of a process of setting a larger power adjustment amount of each power converter to reduce the difference in the amount of stored electricity when the charge / discharge power of the storage battery indicated by the acquired charge / discharge information is large, compared to when the charge / discharge power of the storage battery is small, and a process of setting a smaller threshold when the charge / discharge power of the storage battery indicated by the acquired charge / discharge information is large, compared to when the charge / discharge power of the storage battery is small.

3. The power supply system is capable of supplying power to a low-voltage load as the electrical load and to a high-voltage load to which a higher voltage than the low-voltage load is applied, and power is supplied from each of the battery groups to the low-voltage load via the power converter, while power is supplied from the storage battery to the high-voltage load; the acquisition unit acquires, as the charge / discharge information, high-voltage discharge information indicating that power is being supplied to the high-voltage load when power is being supplied from each of the battery groups to the low-voltage load; and the adjustment unit changes the embodiment by performing at least one of a process of setting a power adjustment amount of each of the power converters to be larger when the high-voltage discharge information is acquired compared to when the high-voltage discharge information is not acquired, and a process of setting the threshold value to be smaller when the high-voltage discharge information is acquired compared to when the high-voltage discharge information is not acquired.

4. The control device for a power converter according to claim 1, wherein the acquisition unit acquires, as the charge / discharge information, a discharge margin, which is the margin of storage capacity in the storage battery relative to a lower discharge limit, and the adjustment unit changes the implementation by performing at least one of a process of setting a larger power adjustment amount of each power converter to reduce the storage capacity difference when the acquired discharge margin is less than a predetermined value, compared to when the discharge margin is equal to or greater than the predetermined value, and a process of setting a smaller threshold when the acquired discharge margin is less than the predetermined value, compared to when the discharge margin is equal to or greater than the predetermined value.

5. The control device for a power converter according to claim 4, wherein the acquisition unit acquires, as the discharge margin, the margin of storage capacity relative to a lower discharge limit in a unit battery with the smallest storage capacity among a plurality of unit batteries constituting the storage battery, and the adjustment unit changes the implementation based on the acquired margin in the unit battery with the smallest storage capacity.

6. The control device for a power converter according to claim 1, wherein the acquisition unit acquires, as the charge / discharge information, a charge margin, which is the margin of storage capacity in the storage battery relative to a charge upper limit, and the adjustment unit changes the implementation by performing at least one of a process of setting a larger power adjustment amount of each power converter to reduce the storage capacity difference when the acquired charge margin is less than a predetermined value, compared to when the charge margin is greater than or equal to the predetermined value, and a process of setting a smaller threshold when the acquired charge margin is less than the predetermined value, compared to when the charge margin is greater than or equal to the predetermined value.

7. The control device for a power converter according to claim 6, wherein the acquisition unit acquires, as the charge margin, the margin of charge in the unit battery with the largest amount of stored power among the plurality of unit batteries constituting the storage battery, relative to the charge upper limit, and the adjustment unit changes the implementation based on the acquired margin in the unit battery with the largest amount of stored power.

8. A power converter control device according to any one of claims 2 to 7, wherein the adjustment unit controls the amount of power adjustment by changing the output voltage of at least one of the power converters.

9. A control device for a power converter as described in claim 8, wherein the adjustment unit changes the implementation of power adjustment by each of the power converters so that power is supplied to the electrical load from the battery group having the larger storage capacity parameter of the first battery group or the second battery group, and power is supplied to the battery group having the smaller storage capacity parameter.

10. A power converter control device according to any one of claims 2 to 7, wherein the adjustment unit controls the amount of power adjustment by limiting the output current of one of the power converters.

11. The power converter control device according to any one of claims 1 to 7, wherein the adjustment unit adjusts the output power of each of the power converters so that the difference in the amount of stored electricity becomes large.

12. A program applicable to a power supply system (10) comprising a storage battery (11) having a first battery group (11A) and a second battery group (11B) connected in series with each other, and a first power converter (21A) and a second power converter (21B) connected to both ends of each battery group, respectively, and supplying output power after power conversion by each power converter to an electrical load, the program causes a computer (40) to execute processes including: a difference calculation process for calculating a storage amount difference, which is a difference between storage amount parameters indicating the storage amount of each battery group; an adjustment process for adjusting the output power by each power converter when the storage amount difference becomes larger than a predetermined threshold; and an acquisition process for acquiring charge / discharge information indicating the charge / discharge state of the storage battery, wherein the adjustment process is a process for changing the mode of power adjustment by each power converter based on the acquired charge / discharge information.

13. A control method for a power converter applied to a power supply system (10) comprising a storage battery (11) having a first battery group (11A) and a second battery group (11B) connected in series with each other, and a first power converter (21A) and a second power converter (21B) connected to both ends of each battery group, and supplying output power after power conversion by each of the power converters to an electrical load, the control method comprising: a difference calculation step of calculating a storage amount difference, which is a difference between storage amount parameters indicating the storage amount of each of the battery groups; an adjustment step of adjusting the output power by each of the power converters when the storage amount difference becomes larger than a predetermined threshold; and an acquisition step of acquiring charge / discharge information indicating the charge / discharge state of the storage battery, wherein in the adjustment step, the mode of power adjustment by each of the power converters is changed based on the charge / discharge information acquired.

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