System with power converter, program and control method

Abstract

A system, a program, and a control method are provided that can appropriately control each power converter depending on the usage status of the system. The system 10 includes modules 100, 200, and 300, each having a positive electrode connector 101, 201, or 301 connectable to a positive electrode terminal of a storage battery 103, 203, or 303, a negative electrode connector 102, 202, or 302 connectable to a negative electrode terminal, and a power converter 110, 210, or 310. A control device 170 included in the system 10 controls the voltage or current of the power converter 110, 210, or 310 in each of the modules 100, 200, or 300.

Description

[Technical Field]

[0001] The present disclosure relates to a system including a power converter, a program, and a control method. [Background technology]

[0002] BACKGROUND ART Conventionally, as described in Patent Document 1, for example, a system is known that includes a power converter connected to a plurality of storage batteries and performs power conversion between the storage batteries by controlling the power converter. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-23722 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a system that includes a power converter provided individually for each of a plurality of power storage units, and it is desirable to appropriately control each power converter depending on the usage status of the system.

[0005] The present disclosure has been made to solve the above-mentioned problems, and its main purpose is to provide a system, a program, and a control method that can appropriately control a power converter depending on the usage status of the system. [Means for solving the problem]

[0006] The present disclosure provides a system including a plurality of modules each having a positive electrode connection part connectable to a positive electrode terminal of a power storage unit, a negative electrode connection part connectable to a negative electrode terminal of the power storage unit, and a power converter, The power converter of each module is a primary circuit including a first high potential side terminal and a first low potential side terminal; a secondary circuit including a second high potential side terminal and a second low potential side terminal; an isolation transformer connecting the primary side circuit and the secondary side circuit; It has.

[0007] In a first aspect of the present disclosure, in each of the modules, a high potential path connecting the positive electrode connecting portion and the first high potential side terminal; In each of the modules, a first low potential path connecting the negative electrode connecting portion and the first low potential side terminal; a second low potential path connecting a middle portion of the high potential path and the second low potential side terminal in each of the modules; a main high potential path connecting the second high potential side terminals of the modules; a main low potential path connecting the first low potential paths of the modules; a control device; Equipped with.

[0008] A second aspect of the present disclosure is a power supply module including: a first high potential path connecting the positive electrode connecting portion and the first high potential side terminal; In each of the modules, a low potential path connecting the negative electrode connecting portion and the first low potential side terminal; a second high potential path connecting a middle portion of the low potential path and the second high potential side terminal in each of the modules; a main high potential path connecting the first high potential paths of the modules; a main low potential path connecting the second low potential side terminals of the modules; a control device; Equipped with.

[0009] In the first and second aspects of the present disclosure, the control device controls the voltage or current of the power converter in each of the modules, and the current control is switching control of the power converter to control the current flowing through the power storage unit to a target current.

[0010] In a first aspect of the present disclosure, the voltage control is switching control of the power converter for controlling the voltage of the second high potential side terminal relative to the negative electrode connection part to a target voltage. In a second aspect of the present disclosure, the voltage control is switching control of the power converter for controlling the voltage of the positive electrode connection part relative to the second low potential side terminal to a target voltage.

[0011] For example, when the power fluctuations of the loads connected to the main high potential path and the main low potential path are large, it is required to improve the responsiveness of the voltage control of the main high potential path relative to the main low potential path.

[0012] Furthermore, for example, when the amount of stored electricity varies among the power storage units, it is necessary to control the current of each power storage unit in consideration of the variation in the amount of stored electricity.

[0013] According to the present disclosure, voltage control or current control of each power converter is selected depending on the usage status of the system, thereby enabling each power converter to be appropriately controlled depending on the usage status of the system. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a configuration diagram of a system according to a first embodiment. [Figure 2] FIG. 1 is a block diagram of a power converter. [Figure 3] 4 is a flowchart of a process executed by the control device. [Figure 4] FIG. 10 is a diagram showing an example of a control pattern when the number of power converters that are current-controlled is one. [Figure 5] FIG. 10 is a diagram showing an example of a control pattern when the number of power converters that are current-controlled is one. [Figure 6] 4 is a diagram showing a setting manner of a target discharge current of a storage battery that is a target of current control during discharging of each storage battery; FIG. [Figure 7] 4 is a diagram showing a setting manner of a target discharge current of a storage battery that is a target of current control during discharging of each storage battery; FIG. [Figure 8]4 is a diagram showing a setting manner of a target charging current for a storage battery that is a target of current control during charging of each storage battery; FIG. [Figure 9] 4 is a diagram showing a setting manner of a target charging current for a storage battery that is a target of current control during charging of each storage battery; FIG. [Figure 10] FIG. 10 is a diagram showing an example of a control pattern when the number of power converters that are current-controlled is two. [Figure 11] 10 is a flowchart of a process executed by a control device according to a second embodiment. [Figure 12] FIG. 10 is a configuration diagram of a system according to a third embodiment. [Figure 13] FIG. 10 is a configuration diagram of a power converter according to another embodiment. [Figure 14] FIG. 10 is a configuration diagram of a power converter according to another embodiment. [Figure 15] FIG. 10 is a configuration diagram of a power converter according to another embodiment. [Figure 16] FIG. 10 is a configuration diagram of a power converter according to another embodiment. [Figure 17] FIG. 10 is a configuration diagram of a power converter according to another embodiment. [Figure 18] FIG. 10 is a configuration diagram of a power converter according to another embodiment. [Figure 19] FIG. 10 is a configuration diagram of a power converter according to another embodiment. [Figure 20] FIG. 10 is a configuration diagram of a system according to another embodiment. [Figure 21] FIG. 10 is a configuration diagram of a system according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Several embodiments will be described with reference to the drawings. In several embodiments, functionally and / or structurally corresponding and / or associated parts may be assigned 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.

[0016] First Embodiment A first embodiment of a system according to the present disclosure will now be described with reference to the drawings. In this embodiment, the system is installed in an electric vehicle such as an electric vehicle or a hybrid vehicle.

[0017] 1 shows a configuration diagram of a system 10 mounted on a vehicle. The system 10 includes a plurality of modules 100, 200, and 300. In this embodiment, the system 10 includes three modules, specifically, a first module 100, a second module 200, and a third module 300. The first, second, and third modules 100, 200, and 300 include positive electrode connectors 101, 201, and 301 that can be connected to positive electrode terminals of storage batteries (corresponding to "power storage units") 103, 203, and 303, respectively, and negative electrode connectors 102, 202, and 302 that can be connected to negative electrode terminals of the storage batteries 103, 203, and 303, respectively. The positive electrode connectors 101, 201, 301 are connected to the positive electrode terminals of the storage batteries 103, 203, 303, and the negative electrode connectors 102, 202, 302 are connected to the negative electrode terminals of the storage batteries 103, 203, 303. The storage batteries 103, 203, 303 are, for example, secondary batteries such as lithium ion batteries or nickel-metal hydride batteries. In this embodiment, the rated voltages of the storage batteries 103, 203, 303 are the same (for example, 400 V).

[0018] The system 10 includes a main high potential path 20, a main low potential path 21, a smoothing capacitor 22, and a load 23. The smoothing capacitor 22 is connected to the main high potential path 20 and the main low potential path 21. The smoothing capacitor 22 is connected in parallel to the load 23.

[0019] The positive electrode side of each of the modules 100, 200, 300 is connected to the main high potential path 20, and the negative electrode side of each of the modules 100, 200, 300 is connected to the main low potential path 21. As a result, each of the modules 100, 200, 300 is connected in parallel to the load 23.

[0020] The load 23 is connected to the main high potential path 20 and the main low potential path 21. Specifically, the load 23 includes a three-phase inverter 23a and a rotating electric machine 23b having armature windings connected to the inverter 23a for the same number of phases. The inverter 23a controls the current flowing through the armature windings of each phase. The rotating electric machine 23b is an on-board main motor, and a rotor of the rotating electric machine 23b is capable of transmitting power to the drive wheels of the vehicle. The rotating electric machine 23b is, for example, a permanent magnet synchronous machine.

[0021] The main high potential path 20 is connected to the positive electrode side of the inverter 23a, and the main low potential path 21 is connected to the negative electrode side of the inverter 23a. The inverter 23a converts DC power supplied from the system 10 into AC power and supplies the converted AC power to each phase winding of the rotating electric machine 23b. In this case, the rotating electric machine 23b serves as a power source for running the vehicle. The rotating electric machine 23b also generates regenerative power using rotational force applied to the rotor. The inverter 23a converts the generated AC power into DC power and outputs the converted DC power to the main high potential path 20.

[0022] Each of the modules 100, 200, and 300 includes a power converter 110, 210, and 310. Hereinafter, the storage battery 103 and the power converter 110 connected to the first module 100 may be referred to as the "first storage battery 103" and the "first power converter 110," the storage battery 203 and the power converter 210 connected to the second module 200 may be referred to as the "second storage battery 203" and the "second power converter 210," and the storage battery 303 and the power converter 310 connected to the third module 300 may be referred to as the "third storage battery 303" and the "third power converter 310."

[0023] A specific description will be given of the connection relationship between the storage battery and the power converter in each of the modules 100, 200, and 300. The configuration of each of the modules 100, 200, and 300 is basically the same. Therefore, the following description will focus on the first module 100.

[0024] In the first module 100, the first power converter 110 includes a first high potential side terminal 111H, a first low potential side terminal 111L, a second high potential side terminal 112H, and a second low potential side terminal 112L.

[0025] The first module 100 includes a high potential path 104 that connects the first high potential side terminal 111H and the positive electrode connecting part 101. The first module 100 includes a first low potential path 105 that connects the first low potential side terminal 111L and the negative electrode connecting part 102.

[0026] The first module 100 includes a second low potential path 106 that connects the second low potential side terminal 112L and an intermediate portion of the high potential path 104. The second high potential side terminal 112H is connected to the main high potential path 20. An intermediate portion of the first low potential path 105 is connected to the main low potential path 21.

[0027] FIG. 2 shows an example of a first power converter 110. The first power converter 110 is a center-tapped isolated DC-DC converter. As shown in FIGS. 1 and 2, the first power converter 110 includes a primary circuit 120 having a first high-potential side terminal 111H and a first low-potential side terminal 111L, and a secondary circuit 130 having a second high-potential side terminal 112H and a second low-potential side terminal 112L. That is, the primary circuit 120 of the first power converter 110 is connected in parallel to the first storage battery 103. Furthermore, the secondary circuit 130 of the first power converter 110 is connected in series to the first storage battery 103.

[0028] The primary side circuit 120 includes first and second upper arm switches S1H and S2H and first and second lower arm switches S1L and S2L. In this embodiment, the first and second upper arm switches S1H and S2H and the first and second lower arm switches S1L and S2L are semiconductor switching elements, more specifically, N-channel MOSFETs. The switches S1H, S2H, S1L, and S2L each have a body diode D1H, D2H, D1L, and D2L. Note that the switches S1H, S2H, S1L, and S2L may be, for example, IGBTs. In this case, a freewheeling diode is connected in anti-parallel to each of the switches S1H, S2H, S1L, and S2L.

[0029] The drain of the first upper arm switch S1H and the drain of the second upper arm switch S2H are connected to a first high potential side terminal 111H. The source of the first upper arm switch S1H is connected to the drain of the first lower arm switch S1L, and the source of the second upper arm switch S2H is connected to the drain of the second lower arm switch S2L. The sources of the first and second lower arm switches S1L and S2L are connected to a first low potential side terminal 111L.

[0030] The secondary circuit 130 includes first to fourth switches SW1 to SW4 and a reactor 132. In this embodiment, the first to fourth switches SW1 to SW4 are semiconductor switching elements, more specifically, N-channel MOSFETs, and each of the switches SW1 to SW4 has a body diode D1 to D4.

[0031] A first end of the reactor 132 is connected to the second high potential side terminal 112H. A second end of the reactor 132 is connected to the drain of the second switch SW2. A source of the second switch SW2 is connected to the source of the first switch SW1. A second end of the reactor 132 is connected to the drain of the fourth switch SW4. A source of the fourth switch SW4 is connected to the source of the third switch SW3.

[0032] The configuration in which the secondary side circuit 130 has the first to fourth switches SW1 to SW4 is configured to select and execute either a positive voltage mode in which the voltage of the second high potential side terminal 112H is higher than that of the second low potential side terminal 112L, or a negative voltage mode in which the voltage of the second high potential side terminal 112H is lower than that of the second low potential side terminal 112L.

[0033] The first power converter 110 includes an isolation transformer 140 that connects the primary circuit 120 and the secondary circuit 130. The isolation transformer 140 includes a primary coil 141 and a secondary coil 142 having a center tap 143. A first end of the primary coil 141 is connected to a connection point between the first upper arm switch S1H and the first lower arm switch S1L, and a second end of the primary coil 141 is connected to a connection point between the second upper arm switch S2H and the second lower arm switch S2L. A first end of the secondary coil 142 is connected to the drain of the first switch SW1, and a second end of the secondary coil 142 is connected to the drain of the third switch SW3. The center tap 143 of the secondary coil 142 is connected to the second low potential terminal 112L.

[0034] The primary circuit 120 includes a first capacitor 121. The secondary circuit 130 includes a second capacitor 131. The first capacitor 121 is connected to the first high potential side terminal 111H and the first low potential side terminal 111L. The second capacitor 131 is connected to the second high potential side terminal 112H and the second low potential side terminal 112L.

[0035] 1, the second power converter 210 includes a first high potential terminal 211H, a first low potential terminal 211L, a second high potential terminal 212H, and a second low potential terminal 212L. The third power converter 310 includes a first high potential terminal 311H, a first low potential terminal 311L, a second high potential terminal 312H, and a second low potential terminal 312L. In the second module 200 and the third module 300, the connections between the terminals 211H, 211L, 212H, 212L, 311H, 311L, 312H, and 312L of the power converters corresponding to each module and the storage batteries 203 and 303 corresponding to each module are the same as in the first module 100. Therefore, a detailed description of the connections will be omitted.

[0036] The second power converter 210 and the third power converter 310 are center-tapped isolated DC-DC converters, similar to the first power converter 110, and include a primary circuit having first high potential side terminals 211H, 311H and first low potential side terminals 211L, 311L, and a secondary circuit having second high potential side terminals 212H, 312H and second low potential side terminals 212L, 312L. In this embodiment, the configurations of the second power converter 210 and the third power converter 310 are basically the same as the configuration of the first power converter 110, and therefore detailed descriptions of the second power converter 210 and the third power converter 310 will be omitted.

[0037] The first power converter 110 includes a drive circuit 160. The drive circuit 160 drives the first and second upper arm switches S1H and S2H, the first and second lower arm switches S1L and S2L, and the first to fourth switches SW1 to SW4 to turn on and off, which are included in the first power converter 110. The first drive circuit 160 charges and discharges the gates of the switches S1H, S2H, S1L, S2L, and SW1 to SW4, and is controlled by a control device 170 included in the system 10.

[0038] Like the first power converter 110, the second and third power converters 210 and 310 also include drive circuits 260 and 360. The configurations of the drive circuits 260 and 360 of the second and third power converters 210 and 310 are basically the same as the configuration of the drive circuit 160 of the first power converter 110, and therefore detailed description of the drive circuits 260 and 360 will be omitted.

[0039] As shown in FIG. 1, the system 10 includes a main voltage sensor 30 and a main current sensor 31. The main voltage sensor 30 detects a system voltage, which is a voltage between the main high potential path 20 and the main low potential path 21. The main current sensor 31 detects a current flowing through the load 23. In the example shown in FIG. 1, the main current sensor 31 detects a current flowing through a portion of the main low potential path 21 that is closer to the load 23 than a connection point between the main low potential path 21 and the first low potential paths 105, 205, and 305. The detection values ​​of the sensors 30 and 31 are input to the control device 170. The main current sensor 31 may also detect a current flowing through a portion of the main high potential path 20 that is closer to the load 23 than a connection point between the main high potential path 20 and the second high potential terminals 112H, 212H, and 312H.

[0040] The modules 100, 200, and 300 each include an individual voltage sensor 155, 255, and 355. The individual voltage sensors 155, 255, and 355 are provided corresponding to the storage batteries 103, 203, and 303, respectively, and detect the voltages of the storage batteries 103, 203, and 303. The detected values ​​of the individual voltage sensors 155, 255, and 355 are input to the control device 170.

[0041] The modules 100, 200, and 300 each include an individual current sensor 150, 250, and 350. The individual current sensors 150, 250, and 350 are provided corresponding to the storage batteries 103, 203, and 303, respectively, and detect the current flowing through the storage batteries 103, 203, and 303. The detected values ​​of the individual current sensors 150, 250, and 350 are input to the control device 170.

[0042] The modules 100, 200, and 300 are each equipped with an individual temperature sensor 156, 256, and 356. The individual temperature sensors 156, 256, and 356 are provided corresponding to the storage batteries 103, 203, and 303, respectively, and detect the temperatures of the storage batteries 103, 203, and 303. The detected values ​​of the individual temperature sensors 156, 256, and 356 are input to the control device 170.

[0043] As shown in FIG. 2, each of the power converters 110, 210, and 310 includes a first voltage sensor 151, a second voltage sensor 154, a first current sensor 152, and a second current sensor 153. The first voltage sensor 151 detects a primary voltage, which is a voltage between a first high potential terminal 111H and a first low potential terminal 111L. The second voltage sensor 154 detects a secondary voltage, which is a voltage between a second high potential terminal 112H and a second low potential terminal 112L. The first current sensor 152 detects a primary current flowing through the primary circuit 120. The second current sensor 153 detects a secondary current flowing through the secondary circuit 130 (e.g., reactor 132). Detected values ​​of the sensors 151, 154, 152, and 153 included in each of the power converters 110, 210, and 310 are input to the control device 170.

[0044] As shown in FIG. 1, the control device 170 is an electronic control unit (ECU) that performs various controls of the system 10, and includes a processor 171 as hardware, a memory unit 172, and a communication bus 173 that connects the processor 171 and the memory unit 172.

[0045] The memory unit 172 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 170. The memory provides the processor 171 with a working area for temporary use when the processor 171 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 171, 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 the processing described below.

[0046] For example, program information stored in a non-transient physical recording medium is installed in the storage unit 172. 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 172.

[0047] The first module 100 includes a positive switch 181 and a negative switch 182. In this embodiment, the positive switch 181 and the negative switch 182 are relays (specifically, for example, mechanical relays). Note that the positive switch 181 and the negative switch 182 may be, for example, semiconductor switching elements.

[0048] The positive electrode switch 181 is provided in a portion of the high potential path 104 closer to the positive electrode connecting part 101 than the connection part with the second low potential path 106. The negative electrode switch 182 is provided in a portion of the first low potential path 105 closer to the negative electrode connecting part 102 than the connection part with the main low potential path 21.

[0049] The second module 200, like the first module 100, includes a positive switch 281 and a negative switch 282. The third module 300, like the first module 100, includes a positive switch 381 and a negative switch 382.

[0050] Next, the processing executed by the control device 170 will be described.

[0051] The control device 170 performs powering control or regenerative control. Powering control is switching control of the inverter 23a that converts DC power supplied from each of the modules 100, 200, and 300 into AC power and supplies it to each phase winding of the rotating electric machine 23b. Regenerative control is switching control of the inverter 23a that converts AC power output from each phase winding of the rotating electric machine 23b into DC power and supplies it to each of the modules 100, 200, and 300.

[0052] During execution of powering control or regenerative control, the control device 170 sets the number Ncv of power converters to be voltage-controlled and the number Ncc of power converters to be current-controlled from among the first, second, and third power converters 110, 210, and 310.

[0053] The voltage control is switching control of the first, second and third power converters 110, 210 and 310 (specifically, the primary side circuit 120 and the secondary side circuit 130) to control the voltage of the second high potential side terminals 112H, 212H and 312H (hereinafter referred to as the first, second and third module voltages) relative to the negative electrode connecting parts 102, 202 and 302 to a target voltage.

[0054] Current control is switching control of the first, second, and third power converters 110, 210, and 310 (specifically, the primary side circuit 120 and the secondary side circuit 130) to control the current flowing through the second high potential side terminals 112H, 212H, and 312H of the first, second, and third power converters 110, 210, and 310 to a target current.

[0055] The control device 170 sets the number Ncv of power converters to be voltage-controlled and the number Ncc of power converters to be current-controlled according to the usage status of the system 10.

[0056] Next, the procedure of the process executed by the control device 170 will be shown with reference to Fig. 3. This process is repeatedly executed at a predetermined cycle. Note that, prior to executing the process of Fig. 3, the control device 170 switches on each of the positive switches 181, 281, 381 and each of the negative switches 182, 282, 382.

[0057] In step S10, the voltages of the first, second and third storage batteries 103, 203 and 303 detected by the individual voltage sensors 155, 255 and 355 (hereinafter referred to as the first, second and third detected voltages Vb1, Vb2 and Vb3) and the temperatures of the first, second and third storage batteries 103, 203 and 303 detected by the individual temperature sensors 156, 256 and 356 (hereinafter referred to as the first, second and third detected temperatures Tb1, Tb2 and Tb3) are acquired.

[0058] In step S11, request information is obtained from an ECU higher than the control device 170. The request information may include a request to execute current control and a request to suppress ripples. The request to execute current control is a request transmitted from the higher ECU when, for example, it is desired to control the total discharge current or the total charge current of each of the storage batteries 103, 203, 303 to a target total current. The request to suppress ripples is a request transmitted from the higher ECU when it is desired to suppress voltage ripples contained in the system voltage and prevent an electrical device (e.g., the load 23) connected to the main high potential path 20 and the main low potential path 21 from abnormally stopping.

[0059] In step S12, it is determined whether the request information includes a request to execute current control. If it is determined in step S12 that a request to execute current control is included, the process proceeds to step S13. In step S13, it is determined whether the request information includes a request to suppress ripple. If it is determined in step S13 that a request to suppress ripple is not included, the process proceeds to step S14.

[0060] In step S14, information on the required response time Tres is obtained from a higher-level ECU. The required response time Tres is the required responsiveness of the system voltage in voltage control. Specifically, for example, the required response time Tres is the required convergence time of the detected voltage to the target voltage Vtgt when the target voltage Vtgt changes stepwise, or the required time for the amount of change in the detected voltage from when the detected voltage starts to change to reach K% (e.g., 63%) of the amount of change in the target voltage Vtgt when the target voltage Vtgt changes stepwise. The shorter the required response time Tres, the higher the required responsiveness of the system voltage.

[0061] In the following step S15, it is determined whether the acquired required response time Tres is equal to or less than the first response threshold Tth1.

[0062] If it is determined in step S15 that the required response time Tres is equal to or less than the first responsiveness threshold Tth1, or if it is determined in step S12 that a request to execute current control is not included, the process proceeds to step S16, where all of the first, second, and third power converters 110, 210, and 310 are voltage-controlled. In the voltage control, the target voltages Vtgt of the first, second, and third module voltages are set to, for example, the same or equivalent values. A situation in which it is determined that the required response time Tres is equal to or less than the first responsiveness threshold Tth1 indicates a situation in which the required system voltage responsiveness is high. By controlling the voltages of all of the first, second, and third power converters 110, 210, and 310 in this situation, it becomes easier to maintain the system voltage at the target voltage even if the power consumption or regenerative power of the load 23 suddenly changes.

[0063] On the other hand, if it is determined in step S15 that the required response time Tres exceeds the first responsiveness threshold Tth1, the process proceeds to step S17. In step S17, it is determined whether the acquired required response time Tres is longer than the first responsiveness threshold Tth1 and equal to or less than the second responsiveness threshold Tth2 (>Tth1).

[0064] If it is determined in step S17 that "Tth1 < Tres ≤ Tth2", the process proceeds to step S18, where two of the first, second, and third power converters 110, 210, 310 are voltage-controlled, and the remaining one power converter is current-controlled. By voltage-controlling two power converters, the responsiveness of the system voltage to the target voltage can be enhanced.

[0065] Using FIGS. 4 and 5, patterns 1 to 7, which are specific examples of the process in step S18, will be described.

[0066] <Pattern 1> Among the first, second, and third power converters 110, 210, 310, assume that the power converter for which the sum of the electrical path lengths from the main high potential path 20 to the load 23 and from the main low potential path 21 to the load 23 is the minimum is the first power converter 110. As shown in FIG. 4, the control device 170 targets the first power converter 110, for which the above sum is the minimum, among the first, second, and third power converters 110, 210, 310 for voltage control.

[0067] As shown in the column of pattern 1 in FIG. 4, assume that the voltage of the first storage battery 103 is 395V, the voltage of the second storage battery 203 is 394V, and the voltage of the third storage battery 303 is 385V. Based on the detected voltages Vb1, Vb2, Vb3, the control device 170 targets the third power converter 310 connected to the third storage battery 303, which is the farthest from the voltage of the first storage battery 103 among the second and third storage batteries 203, 303, for current control. The control device 170 targets the remaining second power converter 210 for voltage control.

[0068] Since the third power converter 310 is targeted for current control and the method for setting the target charge / discharge current described later is used, the variation in the voltages of the storage batteries 103, 203, 303 can be reduced. Also, since the first power converter 110, for which the above sum is the minimum, is targeted for voltage control, the variation in the system voltage can be suppressed while minimizing the influence of the impedance of the above electrical path.

[0069] <Pattern 2> As in pattern 1, the control device 170 selects the first power converter 110, which has the smallest total value, from among the first, second, and third power converters 110, 210, and 310 as the target of voltage control.

[0070] As shown in the column for pattern 2 in FIG. 4, the voltage of the first storage battery 103 is 385 V, the voltage of the second storage battery 203 is 394 V, and the voltage of the third storage battery 303 is 395 V. The control device 170 calculates the average voltage Vave (= (Vb1 + Vb2 + Vb3) / 3) of the first, second, and third detected voltages Vb1, Vb2, and Vb3. Based on the second and third detected voltages Vb2 and Vb3, the control device 170 selects, as the current control target, the third power converter 310 connected to the third storage battery 303 that is farthest from the average voltage Vave (≈391 V) among the second and third storage batteries 203, 303. The control device 170 selects, as the voltage control target, the remaining second power converters 210.

[0071] <Pattern 3> As shown in the column for pattern 3 in Fig. 4, the voltage of the first storage battery 103 is 395V, the voltage of the second storage battery 203 is 386V, and the voltage of the third storage battery 303 is 385V. Based on the detected voltages Vb1, Vb2, and Vb3, the control device 170 selects the second and third power converters 210 and 310 connected to specific batteries (Ncv = 2) (specifically, the second and third storage batteries 203 and 303) that have similar voltages from among the first, second, and third storage batteries 103, 203, and 303 as targets for voltage control. The control device 170 selects the remaining first power converter 110 as targets for current control.

[0072] This reduces the variation in voltage of each of the storage batteries 103, 203, and 303, while suppressing fluctuations in the system voltage.

[0073] <Pattern 4> As shown in the column for pattern 4 in FIG. 4 , the voltage of the first storage battery 103 is 395 V, the voltage of the second storage battery 203 is 390 V, and the voltage of the third storage battery 303 is 385 V. When the control device 170 determines that the difference (5 V) between the first, second, and third detected voltages Vb1, Vb2, and Vb3 is equal, the control device 170 selects the first power converter 110, which has the smallest total voltage, as the target of voltage control among the first, second, and third power converters 110, 210, and 310. The control device 170 selects the third power converter 310, which is connected to the third storage battery 303, which is the furthest from the voltage of the first storage battery 103, as the target of current control among the second and third storage batteries 203 and 303. The control device 170 selects the remaining second power converter 210 as the target of voltage control.

[0074] The control device 170 may control the first power converter 110 as a current control target and the third power converter 310 as a voltage control target.

[0075] <Pattern 5> As shown in the column for pattern 5 in Fig. 5, the voltage of the first storage battery 103 is 395 V, the voltage of the second storage battery 203 is 390 V, and the voltage of the third storage battery 303 is 385 V. During powering control, the control device 170 selects the third power converter 310 connected to the third storage battery 303, which has the lowest voltage among the first, second, and third storage batteries 103, 203, and 303, as the target of current control based on the detected voltages Vb1, Vb2, and Vb3. The control device 170 selects the remaining first and second power converters 110 and 210 as the target of voltage control.

[0076] The higher the voltage of a storage battery, the greater the power it can output. Therefore, according to pattern 5, when the power demand of the load 23 increases suddenly, the output power of the first and second storage batteries 103, 203 becomes relatively greater than the output power of the third storage battery 303. As a result, the voltage variation of the first, second, and third storage batteries 103, 203, 303 can be reduced.

[0077] <Pattern 6> As shown in the column for pattern 6 in Fig. 5, the voltage of the first storage battery 103 is 395V, the voltage of the second storage battery 203 is 390V, and the voltage of the third storage battery 303 is 385V. During execution of regenerative control, the control device 170, based on the detected voltages Vb1, Vb2, and Vb3, selects the first power converter 110 connected to the first storage battery 103, which has the highest voltage, among the first, second, and third storage batteries 103, 203, and 303, as the target of current control. The control device 170 selects the remaining second and third power converters 210 and 310 as the target of voltage control.

[0078] The lower the voltage of a storage battery, the greater the power that can be input. Therefore, according to pattern 6, when the regenerative power of the load 23 increases suddenly, the input power of the second and third storage batteries 203, 303 becomes relatively greater than the input power of the first storage battery 103. As a result, the variation in voltage of the first, second, and third storage batteries 103, 203, 303 can be reduced.

[0079] <Pattern 7> As shown in the column for pattern 7 in FIG. 5, it is assumed that the temperature of the first storage battery 103 is -20°C, the temperature of the second storage battery 203 is -15°C, and the temperature of the third storage battery 303 is -15°C.

[0080] Based on the detected temperatures Tb1, Tb2, and Tb3, the control device 170 selects the first storage battery 103, which has the lowest temperature, as the battery to be heated among the first, second, and third storage batteries 103, 203, and 303. Regardless of the magnitude relationship between the detected voltages Vb1, Vb2, and Vb3, the control device 170 subjects the first power converter 110 connected to the selected first storage battery 103 to current control and subjects the remaining second and third power converters 210 and 310 to voltage control. As the current control of the first power converter 110, the control device 170 performs ripple heating control, which controls the switching of the first power converter 110 so that the current flowing to the first storage battery 103 includes an AC component.

[0081] According to pattern 7, it is possible to promote the temperature rise of the first storage battery 103, which has the lowest temperature.

[0082] Next, a method for setting the target discharge current of the storage batteries connected to the power converter that is the current control target (hereinafter, current-controlled storage batteries) in step S18 will be described with reference to Figures 6 and 7. Note that Figure 6 illustrates an example in which the voltages of the three storage batteries are 395V, 394V, and 385V. Also, Figure 7 illustrates an example in which the voltages of the three storage batteries are 395V, 386V, and 385V.

[0083] The control device 170 calculates the average voltage Vave when the first, second, and third storage batteries 103, 203, and 303 are discharging to the load 23. When the control device 170 determines that the voltage of the current-controlled storage battery is lower than the average voltage Vave as shown in Fig. 6 when the first, second, and third storage batteries 103, 203, and 303 are discharging, the control device 170 sets the target discharge current Idis of the current-controlled storage battery to be smaller than the discharge current Idis (specifically, for example, the current detected by the individual current sensor) of a storage battery whose voltage is higher than the average voltage Vave. This reduces the variation in voltage of each storage battery 103, 203, and 303.

[0084] On the other hand, when the first, second, and third storage batteries 103, 203, and 303 are discharging, if the control device 170 determines that the voltage of the current-controlled storage battery is higher than the average voltage Vave, as shown in Fig. 7, it sets the target discharge current Idis of the current-controlled storage battery to be larger than the discharge current Idis (specifically, for example, the current detected by the individual current sensor) of a storage battery whose voltage is lower than the average voltage Vave. This reduces the variation in voltage of each storage battery 103, 203, and 303.

[0085] Next, a method for setting the target charging current for the current-controlled storage battery in step S18 will be described with reference to Figures 8 and 9. Note that Figure 8 illustrates an example in which the voltages of the three storage batteries are 395V, 394V, and 385V. Also, Figure 9 illustrates an example in which the voltages of the three storage batteries are 395V, 386V, and 385V.

[0086] When the control device 170 is charged from the load 23 to the first, second, and third storage batteries 103, 203, and 303, the control device 170 calculates the average voltage Vave. When the control device 170 is charged to the first, second, and third storage batteries 103, 203, and 303, as shown in FIG. 8, if it is determined that the voltage of the current control storage battery is lower than the average voltage Vave, the target charging current Ichr of the current control storage battery is made larger than the charging current Ichr of the storage battery whose voltage is higher than the average voltage Vave (specifically, for example, the detected current of the individual current sensor). Thereby, the variation in the voltage of each storage battery 103, 203, and 303 can be reduced.

[0087] On the other hand, when the control device 170 is charged to the first, second, and third storage batteries 103, 203, and 303, as shown in FIG. 9, if it is determined that the voltage of the current control storage battery is higher than the average voltage Vave, the target charging current Ichr of the current control storage battery is made smaller than the charging current Ichr of the storage battery whose voltage is higher than the average voltage Vave (specifically, for example, the detected current of the individual current sensor). Thereby, the variation in the voltage of each storage battery 103, 203, and 303 can be reduced.

[0088] Returning to the description of FIG. 3, if a negative determination is made in step S17, the process proceeds to step S19. In step S19, it is determined whether the acquired request response time Tres is longer than the second responsiveness threshold Tth2 and not more than the third responsiveness threshold Tth3 (>Tth2).

[0089] If it is determined in step S19 that "Tth2 < Tres ≦ Tth3", or if it is determined in step S13 that there is a ripple suppression request, the process proceeds to step S20. In step S20, one of the first, second, and third power converters 110, 210, and 310 is voltage-controlled, and the remaining two power converters are current-controlled.

[0090] Using FIG. 10, patterns 8 to 10, which are specific examples of the process of step S20, will be described.

[0091] <Pattern 8> As shown in the column for pattern 8 in FIG. 10, the voltage of the first storage battery 103 is 395V, the voltage of the second storage battery 203 is 394V, and the voltage of the third storage battery 303 is 385V. The control device 170 calculates the average voltage Vave (≈391V). Based on the detected voltages Vb1, Vb2, and Vb3, the control device 170 selects specific (Ncc=2) storage batteries (specifically, the first and third storage batteries 103 and 303) from the first, second, and third storage batteries 103, 203, and 303 in descending order of the deviation of their voltages from the calculated average voltage Vave. The control device 170 subjects the first and third power converters 110 and 310 connected to the selected first and third storage batteries 103 and 303 to current control. The control device 170 subjects the remaining second power converter 210 to voltage control.

[0092] This reduces the variation in voltage among the storage batteries 103, 203, and 303.

[0093] <Pattern 9> As in pattern 1, the control device 170 selects the first power converter 110, which has the smallest total value, as the target of voltage control among the first, second, and third power converters 110, 210, and 310, and selects the remaining second and third power converters 210 and 310 as the target of current control.

[0094] <Pattern 10> As shown in the column for pattern 10 in FIG. 10, it is assumed that the temperature of the first storage battery 103 is -20°C, the temperature of the second storage battery 203 is -20°C, and the temperature of the third storage battery 303 is -15°C.

[0095] Based on the detected temperatures Tb1, Tb2, and Tb3, the control device 170 selects the first and second storage batteries 103, 203, which have the lowest temperatures, as the storage batteries to be heated. The control device 170 subjects the first and second power converters 110, 210 connected to the selected first and second storage batteries 103, 203 to current control, and subjects the remaining third power converter 310 to voltage control. As the current control of the first and second power converters 110, 210, the control device 170 performs ripple heating control, which controls the switching of the first and second power converters 110, 210 so that the current flowing through the first and second storage batteries 103, 203 includes an AC component.

[0096] According to pattern 10, it is possible to promote the temperature increase of the first and second storage batteries 103, 203, which have the lowest temperatures.

[0097] Returning to the explanation of FIG. 3, if it is determined in step S19 that the required response time Tres exceeds the third responsiveness threshold Tth3, the process proceeds to step S21, where all of the first, second and third power converters 110, 210 and 310 are current controlled.

[0098] The target charge / discharge current of the current-controlled storage battery in steps S20 and S21 can be set in the same manner as in step S18.

[0099] Specifically, when the first, second, and third storage batteries 103, 203, and 303 are discharging, if it is determined that the voltage of the current-controlled storage battery is lower than the average voltage Vave, the target discharge current Idis of the current-controlled storage battery is set to be smaller than the discharge current Idis of a storage battery whose voltage is higher than the average voltage Vave. Here, the target discharge current Idis should be set to be smaller the further the voltage of each current-controlled storage battery is from the average voltage Vave. On the other hand, when the first, second, and third storage batteries 103, 203, and 303 are discharging, if it is determined that the voltage of the current-controlled storage battery is higher than the average voltage Vave, the target discharge current Idis of the current-controlled storage battery is set to be larger than the discharge current Idis of a storage battery whose voltage is lower than the average voltage Vave. Here, the target discharge current Idis should be set to be larger the further the voltage of each current-controlled storage battery is from the average voltage Vave.

[0100] When the first, second, and third storage batteries 103, 203, and 303 are being charged, if it is determined that the voltage of the current-controlled storage battery is lower than the average voltage Vave, the target charging current Ichr of the current-controlled storage battery is set to be larger than the charging current Ichr of a storage battery whose voltage is higher than the average voltage Vave. Here, the target charging current Ichr should be set to be larger the further the voltage of each current-controlled storage battery deviates from the average voltage Vave. On the other hand, when the first, second, and third storage batteries 103, 203, and 303 are being charged, if it is determined that the voltage of the current-controlled storage battery is higher than the average voltage Vave, the target charging current Ichr of the current-controlled storage battery is set to be smaller than the charging current Ichr of a storage battery whose voltage is higher than the average voltage Vave. Here, the target charging current Ichr should be set to be smaller the further the voltage of each current-controlled storage battery deviates from the average voltage Vave.

[0101] According to the present embodiment described above, the number of power converters that are voltage-controlled and the number of power converters that are current-controlled can be set according to the usage status of the system 10.

[0102] Second Embodiment The second embodiment will be described below with reference to the drawings, focusing on the differences from the first embodiment. In this embodiment, the voltage difference between the storage batteries 103, 203, and 303 is used instead of the required response time Tres.

[0103] The procedure of the process executed by the control device 170 will be shown using Figure 11. This process is repeatedly executed at a predetermined cycle. Before executing the process of Figure 11, the control device 170 switches on each of the positive switches 181, 281, and 381 and each of the negative switches 182, 282, and 382.

[0104] In step S30, the first, second, and third detected voltages Vb1, Vb2, and Vb3 and the first, second, and third detected temperatures Tb1, Tb2, and Tb3 are acquired.

[0105] In step S31, the request information is obtained from the upper ECU.

[0106] In step S32, it is determined whether the request information includes a request to execute current control. If it is determined in step S32 that a request to execute current control is included, the process proceeds to step S33. In step S33, it is determined whether the request information includes a request to suppress ripple. If it is determined in step S33 that a request to suppress ripple is not included, the process proceeds to step S34.

[0107] In step S34, a voltage difference ΔV between the minimum and maximum voltages of the first, second, and third detected voltages Vb1, Vb2, and Vb3 is calculated. In this embodiment, the voltage difference ΔV corresponds to the "degree of voltage variation." Note that the parameter indicating the degree of voltage variation is not limited to the voltage difference ΔV.

[0108] In the following step S35, it is determined whether the calculated voltage difference ΔV is equal to or smaller than the first voltage threshold Vth1.

[0109] If it is determined in step S35 that the voltage difference ΔV is equal to or less than the first voltage threshold Vth1, or if it is determined in step S32 that a request to execute current control is not included, the process proceeds to step S36, and voltage control is performed on all of the first, second, and third power converters 110, 210, and 310.

[0110] On the other hand, if it is determined in step S35 that the voltage difference ΔV is higher than the first voltage threshold Vth1, the process proceeds to step S37, where it is determined whether the calculated voltage difference ΔV is higher than the first voltage threshold Vth1 and equal to or lower than the second voltage threshold Vth2 (>Vth1).

[0111] If it is determined in step S37 that "Vth1<ΔV≦Vth2", the process proceeds to step S38, where two of the first, second and third power converters 110, 210 and 310 are voltage-controlled and the remaining one is current-controlled.

[0112] Note that a specific example of the process in step S38 is the same as the specific example of the process in step S18. Also, the method for setting the target charge / discharge current of the current-controlled storage battery in step S38 is the same as the method for setting the target discharge current of the current-controlled storage battery in step S18.

[0113] If the determination in step S37 is negative, the process proceeds to step S39. In step S39, it is determined whether the calculated voltage difference ΔV is higher than the second voltage threshold Vth2 and equal to or lower than the third voltage threshold Vth3 (>Vth2).

[0114] If it is determined in step S39 that "Vth2<ΔV≦Vth3" holds, or if it is determined in step S33 that a ripple suppression request exists, the process proceeds to step S40. In step S40, one of the first, second, and third power converters 110, 210, and 310 is voltage-controlled, and the remaining two are current-controlled. Note that a specific example of the process in step S40 is the same as the specific example of the process in step S20.

[0115] If it is determined in step S39 that the voltage difference ΔV exceeds the third voltage threshold Vth2, the process proceeds to step S41, where current control is performed on all of the first, second, and third power converters 110, 210, and 310. The target charge / discharge currents of the current-controlled storage battery in steps S40 and S41 can be set in the same manner as in step S18.

[0116] According to the present embodiment described above, it is possible to achieve the same effects as the first embodiment.

[0117] <Third embodiment> The third embodiment will be described below with reference to the drawings, focusing on the differences from the first and second embodiments. In this embodiment, the configuration of each of the modules 100, 200, and 300 is changed as shown in Fig. 12. First, the configuration of the first module 100 will be described below.

[0118] The first module 100 includes a first high potential path 104, a low potential path 105, and a second high potential path 107. The first high potential path 104 connects the positive electrode connecting part 101 and the first high potential side terminal 111H. The low potential path 105 connects the negative electrode connecting part 102 and the first low potential side terminal 111L. In other words, the primary side circuit 120 of the first power converter 110 is connected in parallel to the first storage battery 103. The second high potential path 107 connects a midpoint of the low potential path 105 and the second high potential side terminal 112H.

[0119] Similarly to the first module 100, the second module 200 includes a first high potential path 204, a low potential path 205, and a second high potential path 207. Similarly to the first module 100, the third module 300 includes a first high potential path 304, a low potential path 305, and a second high potential path 307.

[0120] The main high potential path 20 connects the first high potential paths 104, 204, and 304 of the respective modules 100, 200, and 300. The main low potential path 21 connects the second low potential side terminals 112L, 212L, and 312L of the respective modules 100, 200, and 300. In other words, the secondary side circuits 130 of the respective power converters 110, 210, and 310 are connected in series to the respective storage batteries 103, 203, and 303.

[0121] The positive electrode side switches 181, 281, 381 are provided in the first high potential paths 104, 204, 304 at the positive electrode connecting parts 101, 201, 301 side from the connection part with the main high potential path 20. The negative electrode side switches 182, 282, 382 are provided in the low potential paths 105, 205, 305 at the negative electrode connecting parts 102, 202, 302 side from the connection part with the second high potential paths 107, 207, 307.

[0122] In this embodiment, voltage control is switching control of the first, second, and third power converters 110, 210, and 310 (specifically, the primary side circuit 120 and the secondary side circuit 130) to control the voltage of the positive electrode connection parts 101, 201, and 301 relative to the second low potential side terminals 112L, 212L, and 312L to a target voltage.

[0123] According to the present embodiment described above, it is possible to achieve the same effects as the first embodiment.

[0124] <Other embodiments> The above-described embodiments may be modified as follows.

[0125] The secondary circuit 130 of each of the power converters 110, 210, and 310 may have the configuration shown in FIGS.

[0126] (A) As shown in Fig. 13, the first switch SW1 and the second switch SW2 may be interchanged, and the fourth switch SW4 and the third switch SW3 may be interchanged. In this case, the drain of the first switch SW1 is connected to the drain of the second switch SW2, and the drain of the third switch SW3 is connected to the drain of the fourth switch SW4.

[0127] 14, the first to fourth switches Q1 to Q4 included in the secondary side circuit 130 may be N-channel IGBTs instead of N-channel MOSFETs. In this case, freewheel diodes DD1 to DD4 are connected in anti-parallel to the switches Q1 to Q4, respectively.

[0128] 15, the secondary-side circuit 130 may include a first switch SA and a second switch SB. As in the first embodiment, the first switch SA and the second switch SB are semiconductor switching elements, specifically N-channel MOSFETs. Each of the switches SA and SB has a body diode DA, DB.

[0129] A drain of the first switch SA and a drain of the second switch SB are connected to a second end of the reactor 132. A first end of the secondary coil 142 is connected to a source of the first switch SA. A second end of the secondary coil 142 is connected to a source of the second switch SB. The secondary circuit 130 of this embodiment is configured to be able to operate only in the positive voltage mode out of the positive voltage mode and the negative voltage mode.

[0130] 16, the midpoint tap 143 may be connected to the second end of the reactor 132. In this case, the sources of the first switch SA and the second switch SB may be connected to the second low potential side terminal 112L.

[0131] (D) As shown in Fig. 17, the first and second switches QA and QB included in the secondary-side circuit 130 may be N-channel IGBTs instead of N-channel MOSFETs. In this case, freewheeling diodes DDA and DDB are connected in anti-parallel to the switches QA and QB, respectively. Note that the switches of the secondary-side circuit 130 in Fig. 16 may also be N-channel IGBTs instead of N-channel MOSFETs.

[0132] (E) As shown in FIG. 18, the secondary side circuit 130 may be a circuit including a first switch section R1 and a second switch section R2.

[0133] A first end of the secondary coil 142 and the second low potential side terminal 112L are connected by a first switch section R1. A second end of the secondary coil 142 and the second low potential side terminal 112L are connected by a second switch section R2. The first and second switch sections R1 and R2 are reverse-blocking IGBTs (RB-IGBTs). The first switch section R1 includes a first H switch RH1 and a first L switch RL1 connected in anti-parallel to the first H switch RH1. The second switch section R2 includes a second H switch RH2 and a second L switch RL2 connected in anti-parallel to the second H switch RH2. The secondary circuit 130 shown in FIG. 18 is configured to be able to select and execute either a positive voltage mode or a negative voltage mode.

[0134] (F) As shown in FIG. 19, the secondary-side circuit 130 is not limited to a center-tap circuit and may be a full-bridge circuit. The secondary-side circuit 130 includes a first switch section U1, a second switch section U2, a third switch section U3, and a fourth switch section U4. The first switch section U1 includes a series connection of a first H switch UH1 and a first L switch UL1. The first H switch UH1 and the first L switch UL1 are semiconductor switching elements, specifically N-channel MOSFETs. The source of the first H switch UH1 is connected to the source of the first L switch UL1. The second switch section U2 includes a series connection of a second H switch UH2 and a second L switch UL2, whose sources are connected to each other. The third switch section U3 includes a series connection of a third H switch UH3 and a third L switch UL3, whose sources are connected to each other. The fourth switch section U4 includes a series connection of a fourth H switch UH4 and a fourth L switch UL4, whose sources are connected to each other. The switches UH1, UL1, UH2, UL2, UH3, UL3, UH4, and UL4 have body diodes DH1, DL1, DH2, DL2, DH3, DL3, DH4, and DL4, respectively.

[0135] A second end of the reactor 132 is connected to the second low potential side terminal 112L via a series connection of a first switch section U1 and a second switch section U2. A second end of the reactor 132 is also connected to the second low potential side terminal 112L via a series connection of a third switch section U3 and a fourth switch section U4. A first end of the secondary side coil 142 is connected to the connection point of the first switch section U1 and the second switch section U2. A second end of the secondary side coil 142 is connected to the connection point of the third switch section U3 and the fourth switch section U4.

[0136] The number of modules included in the system 10 is not limited to three, and may be two, four, or more. FIG. 20 shows a system 10 including two modules. In this case, the system 10 may include a series switch 400 that connects the first storage battery 103 and the second storage battery 203 in series. The series switch 400 connects the positive electrode connector 101 of the first module 100 and the negative electrode connector 202 of the second module 200. The series switch 400 is controlled by the control device 170.

[0137] The control device 170 turns on the negative switch 182, the series switch 400, and the positive switch 281, and turns off the positive switch 181 and the negative switch 282. This connects the first storage battery 103 and the second storage battery 203 in series.

[0138] 21, the system 10 may include a low-voltage load 500. The low-voltage load 500 is an on-board auxiliary device, a control device, or the like that operates when supplied with a voltage (e.g., 12 V) lower than the voltage of each storage battery 103, 203.

[0139] The system 10 includes a first auxiliary path 501, a second auxiliary path 502, a third auxiliary path 503, and a fourth auxiliary path 504. A first end of the first auxiliary path 501 is connected to a second high potential side terminal 112H of the first power converter 110. A second end of the first auxiliary path 501 is connected to a positive electrode side of the low voltage load 500. A first end of the second auxiliary path 502 is connected to a second low potential side terminal 112L of the first power converter 110. A second end of the second auxiliary path 502 is connected to a negative electrode side of the low voltage load 500.

[0140] A first end of the third auxiliary path 503 is connected to the second high potential side terminal 212H of the second power converter 210. A second end of the third auxiliary path 503 is connected to the positive electrode side of the low voltage load 500. A first end of the fourth auxiliary path 504 is connected to the second low potential side terminal 212L of the second power converter 210. A second end of the fourth auxiliary path 504 is connected to the negative electrode side of the low voltage load 500.

[0141] The system 10 includes a first auxiliary switch 511, a second auxiliary switch 512, a third auxiliary switch 513, and a fourth auxiliary switch 514. Each of the auxiliary switches 511-514 is a mechanical relay or a semiconductor switching element. When turned off, each of the auxiliary switches 511-514 blocks bidirectional current flow, and when turned on, each of the auxiliary switches 511-514 allows bidirectional current flow. Each of the auxiliary switches 511-514 is controlled by the control device 170.

[0142] The first auxiliary switch 511 is provided in the first auxiliary path 501. The second auxiliary switch 512 is provided in the second auxiliary path 502. The third auxiliary switch 513 is provided in the third auxiliary path 503. The fourth auxiliary switch 514 is provided in the fourth auxiliary path 504.

[0143] The system 10 includes a first module switch 183 and a second module switch 283. Each of the module switches 183, 283 is a mechanical relay or a semiconductor switching element. When turned off, each of the switches 183, 283, 182, and 282 blocks bidirectional current flow, and when turned on, allows bidirectional current flow. Each of the module switches 183, 283 is controlled by the control device 170.

[0144] By turning on the first and second auxiliary switches 511, 512, the secondary circuit 130 of the first power converter 110 and the low-voltage load 500 are electrically connected. In this case, power can be supplied from the first power converter 110 to the low-voltage load 500. Furthermore, by turning on the third and fourth auxiliary switches 513, 514, the secondary circuit 130 of the second power converter 210 and the low-voltage load 500 are electrically connected. In this case, power can be supplied from the second power converter 210 to the low-voltage load 500.

[0145] The control device 170 turns off the first module switch 183 and the positive side switch 181. This electrically insulates the low-voltage load 500 from the high-voltage side components, such as the first storage battery 103 and the load 23. The control device 170 also turns off the second module switch 283 and the negative side switch 282. This electrically insulates the low-voltage load 500 from the high-voltage side components, such as the second storage battery 203 and the load 23.

[0146] The load connected to the system is not limited to the inverter 23a and the rotating electrical machine 23b, but may be a DC-DC converter, an external charger, a heater, or the like.

[0147] The power converter is not limited to the configuration shown in FIG. 2, and may be a non-isolated DC-DC converter such as a resonant DC-DC converter or a buck converter.

[0148] The power storage unit provided in each module is not limited to a storage battery, but may be, for example, a large-capacity electric double layer capacitor, or both a storage battery and an electric double layer capacitor. The power storage unit may also be a fuel cell.

[0149] The system 10 is not limited to being installed in a vehicle, but may also be installed in a moving object such as an aircraft or a ship. If the moving object is an aircraft, the rotating electric machine serves as the power source for the aircraft's flight, and if the moving object is a ship, the rotating electric machine serves as the power source for the ship's navigation. Furthermore, the system 10 is not limited to being installed in a moving object, but can also be used as a stationary power source.

[0150] The control device and method described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control device and method described herein may be implemented by a special-purpose computer configured with a processor comprising one or more dedicated hardware logic circuits. Alternatively, the control device and method described herein may be implemented by one or more special-purpose computers configured with a processor and memory programmed to perform one or more functions in combination with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions executed by a computer.

[0151] The following describes characteristic configurations extracted from the above-described embodiments. [Configuration 1] A system (10) including a plurality of modules (100, 200, 300) each having a positive electrode connector (101, 201, 301) connectable to a positive electrode terminal of a power storage unit (103, 203, 303), a negative electrode connector (102, 202, 302) connectable to a negative electrode terminal of the power storage unit, and a power converter (110, 210, 310), The power converter of each module is a primary circuit (120) including first high potential side terminals (111H, 211H, 311H) and first low potential side terminals (111L, 211L, 311L); a secondary circuit (130) including second high potential side terminals (112H, 212H, 312H) and second low potential side terminals (112L, 212L, 312L); an isolation transformer (140) connecting the primary side circuit and the secondary side circuit; and In each of the modules, a high potential path (104, 204, 304) connecting the positive electrode connection portion and the first high potential side terminal; In each of the modules, a first low potential path (105, 205, 305) connecting the negative electrode connection portion and the first low potential side terminal; In each of the modules, a second low potential path (106, 206, 306) connecting a middle portion of the high potential path and the second low potential side terminal; a main high potential path (20) connecting the second high potential side terminals of the modules; a main low potential path (21) connecting the first low potential paths of the modules; a control device (170); Equipped with the control device controls the voltage or current of the power converter in each of the modules; the voltage control is switching control of the power converter for controlling the voltage of the second high potential side terminal with respect to the negative electrode connecting portion to a target voltage, The current control is switching control of the power converter for controlling the current flowing in the power storage unit to a target current. [Configuration 2] A system (10) including a plurality of modules (100, 200, 300) each having a positive electrode connector (101, 201, 301) connectable to a positive electrode terminal of a power storage unit (103, 203, 303), a negative electrode connector (102, 202, 302) connectable to a negative electrode terminal of the power storage unit, and a power converter (110, 210, 310), The power converter of each module is a primary circuit (120) including first high potential side terminals (111H, 211H, 311H) and first low potential side terminals (111L, 211L, 311L); a secondary circuit (130) including second high potential side terminals (112H, 212H, 312H) and second low potential side terminals (112L, 212L, 312L); an isolation transformer (140) connecting the primary side circuit and the secondary side circuit; and In each of the modules, a first high potential path (104, 204, 304) connecting the positive electrode connection portion and the first high potential side terminal; In each of the modules, a low potential path (105, 205, 305) connecting the negative electrode connection portion and the first low potential side terminal; In each of the modules, a second high potential path (107, 207, 307) connecting a middle portion of the low potential path and the second high potential side terminal; a main high potential path (20) connecting the first high potential paths of the modules; a main low potential path (21) connecting the second low potential side terminals of the modules; a control device (170); Equipped with the control device controls the voltage or current of the power converter in each of the modules; the voltage control is switching control of the power converter for controlling the voltage of the positive electrode connection part with respect to the second low potential side terminal to a target voltage, The current control is switching control of the power converter for controlling the current flowing in the power storage unit to a target current. [Configuration 3] The control device Obtaining the required response (Tres) of the voltage control; The system according to configuration 1 or 2, wherein when the acquired required responsiveness is high, the number of power converters to be subjected to the voltage control is increased among the power converters compared to when the required responsiveness is low. [Configuration 4] The system according to configuration 1 or 2, wherein the control device increases the number of the power converters that perform the current control when the degree of variation in the voltages of the power storage units is large compared to when the degree of variation is small. [Configuration 5] The control device selecting some of the power storage units as power storage units to be heated, performing ripple temperature rise control to perform switching control of the power converter connected to the selected power storage unit to be heated, so as to cause a current including an AC component to flow through the selected power storage unit to be heated; The system according to any one of configurations 1 to 4, wherein at least one of the power converters other than the power converter connected to the power storage unit to be heated is targeted for voltage control. [Configuration 6] the number of modules is three or more; The system described in any one of configurations 1 to 4, wherein when the control device performs the voltage control on two or more specific power converters that are some of the power converters, the control device targets the power converters connected to the specific power storage units that have similar voltages among the power storage units. [Configuration 7] the number of modules is three or more; The system described in any one of configurations 1 to 4, wherein when the control device performs the current control on two or more specific power converters that are a part of the power converters, the control device selects the specific power storage units from the power storage units in descending order of voltage deviation from an average voltage (Vave) of the power storage units, and targets the power converters connected to the selected power storage units for the current control. [Configuration 8] The control device The system according to any one of configurations 1 to 7, wherein, among the power converters, the power converter having the smallest total value of the length of the electrical path to the load (23) via the main high potential path and the length of the electrical path to the load via the main low potential path is targeted for the voltage control. [Configuration 9] When the power storage units are charged and at least one of the power converters is current-controlled, the control device when it is determined that the voltage of the power storage unit connected to the current-controlled power converter is lower than the average voltage (Vave) of each power storage unit, setting a target charging current of the power storage unit connected to the current-controlled power converter to be larger than the charging current of the power storage unit having a voltage higher than the average voltage; The system according to any one of configurations 1 to 8, wherein, when it is determined that the voltage of the power storage unit connected to the current-controlled power converter is higher than the average voltage, the system sets a target charging current of the power storage unit connected to the current-controlled power converter to be smaller than the charging current of the power storage unit whose voltage is lower than the average voltage. [Configuration 10] When the power storage units are discharged and at least one of the power converters is current-controlled, the control device when it is determined that the voltage of the power storage unit connected to the current-controlled power converter is higher than the average voltage (Vave) of each power storage unit, setting a target discharge current of the power storage unit connected to the current-controlled power converter to be higher than the discharge current of the power storage unit whose voltage is lower than the average voltage; The system according to any one of configurations 1 to 8, wherein, when it is determined that the voltage of the power storage unit connected to the current-controlled power converter is lower than the average voltage, the system sets a target discharge current of the power storage unit connected to the current-controlled power converter to be smaller than the discharge current of the power storage unit whose voltage is higher than the average voltage. [Explanation of symbols]

[0152] 10...system, 20...main high potential path, 21...main low potential path, 100, 200, 300...first, second, third modules, 101, 201, 301...positive electrode connection part, 102, 202, 302...negative electrode connection part, 103, 203, 303...first, second, third storage battery, 104, 204, 304...first high potential path, 105, 205, 305...first low potential path high potential path, 106, 206, 306... second low potential path, 111H, 211H, 311H... first high potential side terminal, 111L, 211L, 311L... first low potential side terminal, 112H, 212H, 312H... second high potential side terminal, 112L, 212L, 312L... second low potential side terminal, 110, 210, 310... first, second, third power converter, 170... control device.

Claims

1. A system (10) including a plurality of modules (100, 200, 300) each having a positive electrode connector (101, 201, 301) connectable to a positive electrode terminal of a storage battery unit (103, 203, 303), a negative electrode connector (102, 202, 302) connectable to a negative electrode terminal of the storage battery unit, and a power converter (110, 210, 310), The power converter of each module is a primary circuit (120) including first high potential side terminals (111H, 211H, 311H) and first low potential side terminals (111L, 211L, 311L); a secondary circuit (130) including second high potential side terminals (112H, 212H, 312H) and second low potential side terminals (112L, 212L, 312L); an isolation transformer (140) connecting the primary side circuit and the secondary side circuit; and In each of the modules, a high potential path (104, 204, 304) connecting the positive electrode connection portion and the first high potential side terminal; In each of the modules, a first low potential path (105, 205, 305) connecting the negative electrode connection portion and the first low potential side terminal; In each of the modules, a second low potential path (106, 206, 306) connecting a middle portion of the high potential path and the second low potential side terminal; a main high potential path (20) connecting the second high potential side terminals of the modules; a main low potential path (21) connecting the first low potential paths of the modules; a control device (170); Equipped with the control device controls the voltage or current of the power converter in each of the modules; the voltage control is switching control of the power converter for controlling the voltage of the second high potential side terminal with respect to the negative electrode connecting portion to a target voltage; The current control is switching control of the power converter for controlling the current flowing in the power storage unit to a target current.

2. A system (10) including a plurality of modules (100, 200, 300) each having a positive electrode connector (101, 201, 301) connectable to a positive electrode terminal of a storage battery unit (103, 203, 303), a negative electrode connector (102, 202, 302) connectable to a negative electrode terminal of the storage battery unit, and a power converter (110, 210, 310), The power converter of each module is a primary circuit (120) including first high potential side terminals (111H, 211H, 311H) and first low potential side terminals (111L, 211L, 311L); a secondary circuit (130) including second high potential side terminals (112H, 212H, 312H) and second low potential side terminals (112L, 212L, 312L); an isolation transformer (140) connecting the primary side circuit and the secondary side circuit; and In each of the modules, a first high potential path (104, 204, 304) connecting the positive electrode connection portion and the first high potential side terminal; In each of the modules, a low potential path (105, 205, 305) connecting the negative electrode connection portion and the first low potential side terminal; In each of the modules, a second high potential path (107, 207, 307) connecting a middle portion of the low potential path and the second high potential side terminal; a main high potential path (20) connecting the first high potential paths of the modules; a main low potential path (21) connecting the second low potential side terminals of the modules; a control device (170); Equipped with the control device controls the voltage or current of the power converter in each of the modules; the voltage control is switching control of the power converter for controlling the voltage of the positive electrode connection part with respect to the second low potential side terminal to a target voltage, The current control is switching control of the power converter for controlling the current flowing in the power storage unit to a target current.

3. The control device Obtaining the required response of the voltage control (Tres); The system according to claim 1 or 2, wherein when the acquired required responsiveness is high, the number of power converters to be subjected to the voltage control is increased compared to when the acquired required responsiveness is low.

4. 3 . The system according to claim 1 , wherein the control device increases the number of the power converters that perform the current control when the degree of variation in voltage of each of the power storage units is large compared to when the degree of variation is small.

5. The control device selecting some of the power storage units as power storage units to be heated, performing ripple temperature rise control to perform switching control of the power converter connected to the selected power storage unit to be heated, so as to cause a current including an AC component to flow through the selected power storage unit to be heated; The system according to claim 1 , wherein at least one of the power converters other than the power converter connected to the power storage unit to be heated is targeted for the voltage control.

6. the number of modules is three or more; 3. The system according to claim 1, wherein when the control device performs the voltage control on two or more specific power converters that are some of the power converters, the control device targets the power converters connected to the specific power storage units that have similar voltages among the power storage units.

7. the number of modules is three or more; 3. The system according to claim 1, wherein, when performing the current control on two or more specific power converters that are some of the power converters, the control device selects the specific power storage units from the power storage units in descending order of deviation of voltage from an average voltage (Vave) of the power storage units, and targets the power converters connected to the selected power storage units for the current control.

8. The control device 3. The system according to claim 1, wherein the power converter having the smallest total length of an electrical path to a load (23) via the main high potential path and the smallest total length of an electrical path to the load via the main low potential path is targeted for the voltage control.

9. When the power storage units are charged and at least one of the power converters is current-controlled, the control device when it is determined that the voltage of the power storage unit connected to the current-controlled power converter is lower than the average voltage (Vave) of the power storage units, setting a target charging current of the power storage unit connected to the current-controlled power converter to be larger than the charging current of the power storage unit having a voltage higher than the average voltage; 3. The system according to claim 1, wherein, when it is determined that the voltage of the power storage unit connected to the current-controlled power converter is higher than the average voltage, the system sets a target charging current for the power storage unit connected to the current-controlled power converter to be smaller than the charging current for the power storage unit having a voltage lower than the average voltage.

10. When the power storage units are discharged and at least one of the power converters is current-controlled, the control device when it is determined that the voltage of the power storage unit connected to the current-controlled power converter is higher than an average voltage (Vave) of each power storage unit, setting a target discharge current of the power storage unit connected to the current-controlled power converter to be higher than a discharge current of the power storage unit whose voltage is lower than the average voltage; 3. The system according to claim 1, wherein, when it is determined that the voltage of the power storage unit connected to the current-controlled power converter is lower than the average voltage, the system sets a target discharge current of the power storage unit connected to the current-controlled power converter to be smaller than the discharge current of the power storage unit having a voltage higher than the average voltage.

11. A program applied to a system (10) including a plurality of modules (100, 200, 300) each having a positive electrode connector (101, 201, 301) connectable to a positive electrode terminal of a storage battery unit (103, 203, 303), a negative electrode connector (102, 202, 302) connectable to a negative electrode terminal of the storage battery unit, and a power converter (110, 210, 310), The power converter of each module is a primary circuit (120) including first high potential side terminals (111H, 211H, 311H) and first low potential side terminals (111L, 211L, 311L); a secondary circuit (130) including second high potential side terminals (112H, 212H, 312H) and second low potential side terminals (112L, 212L, 312L); an isolation transformer (140) connecting the primary side circuit and the secondary side circuit; and The system comprises: In each of the modules, a high potential path (104, 204, 304) connecting the positive electrode connection portion and the first high potential side terminal; In each of the modules, a first low potential path (105, 205, 305) connecting the negative electrode connection portion and the first low potential side terminal; In each of the modules, a second low potential path (106, 206, 306) connecting a middle portion of the high potential path and the second low potential side terminal; a main high potential path (20) connecting the second high potential side terminals of the modules; a main low potential path (21) connecting the first low potential paths of the modules; Equipped with causing a processor (171) to execute a process for voltage control or current control of the power converter in each of the modules; the voltage control is switching control of the power converter for controlling the voltage of the second high potential side terminal with respect to the negative electrode connecting portion to a target voltage; The current control is switching control of the power converter for controlling the current flowing in the power storage unit to a target current.

12. A control method applied to a system (10) including a plurality of modules (100, 200, 300) each having a positive electrode connector (101, 201, 301) connectable to a positive electrode terminal of a power storage unit (103, 203, 303), a negative electrode connector (102, 202, 302) connectable to a negative electrode terminal of the power storage unit, and a power converter (110, 210, 310), The power converter of each module is a primary circuit (120) including first high potential side terminals (111H, 211H, 311H) and first low potential side terminals (111L, 211L, 311L); a secondary circuit (130) including second high potential side terminals (112H, 212H, 312H) and second low potential side terminals (112L, 212L, 312L); an isolation transformer (140) connecting the primary side circuit and the secondary side circuit; and The system comprises: In each of the modules, a high potential path (104, 204, 304) connecting the positive electrode connection portion and the first high potential side terminal; In each of the modules, a first low potential path (105, 205, 305) connecting the negative electrode connection portion and the first low potential side terminal; In each of the modules, a second low potential path (106, 206, 306) connecting a middle portion of the high potential path and the second low potential side terminal; a main high potential path (20) connecting the second high potential side terminals of the modules; a main low potential path (21) connecting the first low potential paths of the modules; Equipped with a step of voltage-controlling or current-controlling the power converter in each of the modules; the voltage control is switching control of the power converter for controlling the voltage of the second high potential side terminal with respect to the negative electrode connecting portion to a target voltage; The current control is a switching control of the power converter for controlling the current flowing in the power storage unit to a target current.

13. A program applied to a system (10) including a plurality of modules (100, 200, 300) each having a positive electrode connector (101, 201, 301) connectable to a positive electrode terminal of a storage battery unit (103, 203, 303), a negative electrode connector (102, 202, 302) connectable to a negative electrode terminal of the storage battery unit, and a power converter (110, 210, 310), The power converter of each module is a primary circuit (120) including first high potential side terminals (111H, 211H, 311H) and first low potential side terminals (111L, 211L, 311L); a secondary circuit (130) including second high potential side terminals (112H, 212H, 312H) and second low potential side terminals (112L, 212L, 312L); an isolation transformer (140) connecting the primary side circuit and the secondary side circuit; and The system comprises: In each of the modules, a first high potential path (104, 204, 304) connecting the positive electrode connection portion and the first high potential side terminal; In each of the modules, a low potential path (105, 205, 305) connecting the negative electrode connection portion and the first low potential side terminal; In each of the modules, a second high potential path (107, 207, 307) connecting a middle portion of the low potential path and the second high potential side terminal; a main high potential path (20) connecting the first high potential paths of the modules; a main low potential path (21) connecting the second low potential side terminals of the modules; Equipped with causing a processor (171) to execute a process for voltage control or current control of the power converter in each of the modules; the voltage control is switching control of the power converter for controlling the voltage of the positive electrode connection part with respect to the second low potential side terminal to a target voltage, The current control is switching control of the power converter for controlling the current flowing in the power storage unit to a target current.

14. A control method applied to a system (10) including a plurality of modules (100, 200, 300) each having a positive electrode connector (101, 201, 301) connectable to a positive electrode terminal of a power storage unit (103, 203, 303), a negative electrode connector (102, 202, 302) connectable to a negative electrode terminal of the power storage unit, and a power converter (110, 210, 310), The power converter of each module is a primary circuit (120) including first high potential side terminals (111H, 211H, 311H) and first low potential side terminals (111L, 211L, 311L); a secondary circuit (130) including second high potential side terminals (112H, 212H, 312H) and second low potential side terminals (112L, 212L, 312L); an isolation transformer (140) connecting the primary side circuit and the secondary side circuit; and The system comprises: In each of the modules, a first high potential path (104, 204, 304) connecting the positive electrode connection portion and the first high potential side terminal; In each of the modules, a low potential path (105, 205, 305) connecting the negative electrode connection portion and the first low potential side terminal; In each of the modules, a second high potential path (107, 207, 307) connecting a middle portion of the low potential path and the second high potential side terminal; a main high potential path (20) connecting the first high potential paths of the modules; a main low potential path (21) connecting the second low potential side terminals of the modules; Equipped with a step of voltage-controlling or current-controlling the power converter in each of the modules; the voltage control is switching control of the power converter for controlling the voltage of the positive electrode connection part with respect to the second low potential side terminal to a target voltage, The current control is a switching control of the power converter for controlling the current flowing in the power storage unit to a target current.

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