System including power converter, program, and system control method

Abstract

A system (10) comprises a plurality of modules (100, 200, 300) having: positive electrode connection parts (101, 201, 301) connectable to the positive electrode terminals of electricity storage units (103, 203, 303); negative electrode connection parts (102, 202, 302) connectable to the negative electrode terminals of the electricity storage units; and power converters (110, 210, 310). A secondary-side circuit (130) of each power converter allows current to flow from second low-potential-side terminals (112L, 212L, 312L) to second high-potential-side terminals (112H, 212H, 312H) and prevents current from flowing from the second high-potential-side terminals to the second low-potential-side terminals.

Description

System, Program, and System Control Method Including a Power Converter ,

[0008] , ,

[0007] ,

[0006] Cross - Reference to Related Applications

[0001] This application is based on Japanese Application No. 2024 - 156946 filed on September 10, 2024, the content of which is incorporated herein by reference.

[0002] This disclosure relates to a system, a program, and a system control method including a power converter.

[0003] Conventionally, as described in, for example, Patent Document 1, 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.

[0004] Japanese Unexamined Patent Application Publication No. 2022 - 23722

[0005] There is a system including power converters individually provided corresponding to a plurality of power storage units respectively. In this system, a closed circuit including the plurality of power storage units and the power converters may be formed. In this case, if there is a voltage difference between the power storage units, there is a concern that a circulating current may occur between the power storage units. Therefore, it is desirable to suppress the generation of the circulating current.

[0006] This disclosure has been made to solve the above problems, and its main object is to provide a system, a program, and a system control method capable of suppressing the generation of a circulating current.

[0007] In a system including a plurality of modules each having a positive electrode connection part connectable to a positive electrode terminal of a power storage part, a negative electrode connection part connectable to a negative electrode terminal of the power storage part, and a power converter, the power converter of each module includes a primary - side circuit including a first high - potential - side terminal, a first low - potential - side terminal, and a first capacitor connecting the first high - potential - side terminal and the first low - potential - side terminal, a secondary - side circuit including a second high - potential - side terminal, a second low - potential - side terminal, and a second capacitor connecting the second high - potential - side terminal and the second low - potential - side terminal, and an isolation transformer connecting the primary - side circuit and the secondary - side circuit. [[ID=​A first aspect of the present disclosure includes, in each module, a high-potential path connecting the positive electrode connection portion and the first high-potential terminal; in each module, a first low-potential path connecting the negative electrode connection portion and the first low-potential terminal; in each module, a second low-potential path connecting an intermediate portion of the high-potential path and the second low-potential terminal; a main high-potential path connecting the second high-potential terminal of each module; a main low-potential path connecting the first low-potential path of each module; and in each module, a switch switching portion provided in the portion of the high-potential path closer to the positive electrode connection portion than the portion connected to the second low-potential path, or in the portion of the first low-potential path closer to the negative electrode connection portion than the portion connected to the main low-potential path.

[0009] A second aspect of the present disclosure includes, in each module, a first high-potential path connecting the positive electrode connection portion and the first high-potential terminal; in each module, a low-potential path connecting the negative electrode connection portion and the first low-potential terminal; in each module, a second high-potential path connecting an intermediate portion of the low-potential path and the second high-potential terminal; a main high-potential path connecting the first high-potential path of each module; a main low-potential path connecting the second low-potential terminal of each module; and in each module, a switch switching portion provided in the portion of the first high-potential path closer to the positive electrode connection portion than the portion connected to the main high-potential path, or in the portion of the low-potential path closer to the negative electrode connection portion than the portion connected to the second high-potential path.

[0010] In the first and second embodiments of this disclosure, the switch switching unit is a series connection of a precharge switch and a precharge resistor and a parallel connection of a main switch.

[0011] Prior to driving the system, each power converter requires pre-charging of the first capacitor in the primary circuit and the second capacitor in the secondary circuit. To expedite the completion of pre-charging of the first and second capacitors in each power converter, the pre-charge switches of each module are switched on at the same timing.

[0012] In this case, if there is a voltage difference between the energy storage units, there is a concern that a circulating current will flow in the closed circuit, which includes the secondary circuit of one module and the energy storage unit connected to this secondary circuit, the secondary circuit of another module and the energy storage unit connected to this secondary circuit, the main high-potential path, and the main low-potential path. If the precharge switch, through which the circulating current is flowing, is switched off, there is a concern that the precharge switch will fail. Furthermore, in order to avoid precharge switch failure, if the precharge switch is switched off only after waiting until the circulating current stops flowing, the precharge completion timing of the first and second capacitors will be delayed.

[0013] Therefore, in the first embodiment of the present disclosure, the secondary circuit of each module has the function of preventing the flow of current from the second high-potential terminal to the second low-potential terminal.

[0014] This allows the secondary circuit to block current attempting to flow into a particular module from other modules via the main high-potential path. As a result, the generation of circulating current can be suppressed.

[0015] On the other hand, in the first embodiment of the present disclosure, the secondary circuit of each module has a function to allow current to flow from the second low-potential terminal to the second high-potential terminal.

[0016] This prevents situations where the pre-charging of the second capacitor is hindered when the pre-charge switch of each module is turned on.

[0017] In the second embodiment of this disclosure, similar to the characteristic configuration of the first embodiment, the secondary circuit of each module has the function of allowing current to flow from the second low-potential terminal to the second high-potential terminal and preventing current from flowing from the second high-potential terminal to the second low-potential terminal.

[0018] Thus, according to this disclosure, it is possible to suppress the generation of circulating current while shortening the period from when the precharge switch is turned on until the precharging of the first and second capacitors is completed.

[0019] The above-mentioned and other purposes, features and advantages of this disclosure will become clearer from the following detailed description with reference to the accompanying drawings. The drawings are as follows: Figure 1 is a diagram of the system configuration according to the first embodiment; Figure 2 is a diagram of the power converter configuration; Figure 3 is a diagram showing a part of the secondary circuit of the power converter; Figure 4 is a flowchart of precharge control; Figure 5 is a diagram showing an example of precharge control; Figure 6 is a diagram showing an example of precharge control; Figure 7 is a diagram showing an example of precharge control; Figure 8 is a diagram showing an example of precharge control; Figure 9 is a diagram showing an example of precharge control; Figure 10 is a diagram of the system configuration according to a modification of the first embodiment; and Figure 11 is a diagram of the system configuration according to the second embodiment. Figure 12 is a system configuration diagram relating to a modified example of the second embodiment, Figure 13 is a configuration diagram of a power converter according to the third embodiment, Figure 14 is a flowchart of precharge control, Figure 15 is a configuration diagram of a power converter according to another embodiment, Figure 16 is a configuration diagram of a power converter according to another embodiment, Figure 17 is a configuration diagram of a power converter according to another embodiment, Figure 18 is a flowchart of precharge control according to another embodiment, Figure 19 is a configuration diagram of a power converter according to another embodiment, and Figure 20 is a configuration diagram of a power converter according to another embodiment.

[0020] Multiple embodiments will be described with reference to the drawings. In multiple embodiments, functionally and / or structurally corresponding and / or related parts may be given the same reference numeral, or reference numerals that differ by hundreds or more digits. For corresponding and / or related parts, refer to the descriptions of other embodiments.

[0021] <First Embodiment> Hereinafter, a first embodiment of the system relating to this disclosure will be described with reference to the drawings. In this embodiment, the system constitutes a system installed in an electric vehicle such as an electric vehicle or a hybrid vehicle.

[0022] Figure 1 shows a configuration diagram of the system 10 installed in the vehicle. The system 10 comprises a plurality of modules 100, 200, and 300. In this embodiment, the system 10 comprises 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 each include positive electrode connection parts 101, 201, and 301 that can be connected to the positive electrode terminals of the storage batteries (corresponding to the "energy storage section") 103, 203, and 303, and negative electrode connection parts 102, 202, and 302 that can be connected to the negative electrode terminals of the storage batteries 103, 203, and 303. The positive electrode connection parts 101, 201, and 301 are connected to the positive terminals of the storage batteries 103, 203, and 303, and the negative electrode connection parts 102, 202, and 302 are connected to the negative terminals of the storage batteries 103, 203, and 303. The storage batteries 103, 203, and 303 are secondary batteries such as lithium-ion batteries or nickel-metal hydride batteries. In this embodiment, the rated voltage (for example, 400V) of the storage batteries 103, 203, and 303 is the same.

[0023] System 10 comprises 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.

[0024] The positive terminals of each module 100, 200, and 300 are connected to the main high-potential path 20, and the negative terminals of each module 100, 200, and 300 are connected to the main low-potential path 21. As a result, each module 100, 200, and 300 are connected in parallel to the load 23.

[0025] The load 23 is connected to the main high-potential path 20 and the main low-potential path 21. Specifically, the load 23 comprises a three-phase inverter 23a and a rotating electric machine 23b connected to the inverter 23a, which has armature windings for each phase. The inverter 23a controls the current flowing through the armature windings of each phase. The rotating electric machine 23b is a vehicle-mounted main machine, and the rotor of the rotating electric machine 23b is capable of transmitting power to the vehicle's drive wheels. The rotating electric machine 23b is, for example, a permanent magnet synchronous machine.

[0026] The main high-potential path 20 is connected to the positive terminal side of the inverter 23a, and the main low-potential path 21 is connected to the negative terminal side of the inverter 23a. The inverter 23a converts the 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 becomes the power source for the vehicle's movement. The rotating electric machine 23b also performs regenerative power generation using the 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.

[0027] Each module 100, 200, and 300 is equipped with a power converter 110, 210, and 310. Hereinafter, the battery 103 and power converter 110 connected to the first module 100 will be referred to as the "first battery 103" and the "first power converter 110," the battery 203 and power converter 210 connected to the second module 200 will be referred to as the "second battery 203" and the "second power converter 210," and the battery 303 and power converter 310 connected to the third module 300 will be referred to as the "third battery 303" and the "third power converter 310."

[0028] The connection relationship between the battery and the power converter in each module 100, 200, and 300 will be explained in detail. The configurations of each module 100, 200, and 300 are basically the same. Therefore, the following explanation will focus on the first module 100.

[0029] In the first module 100, the first power converter 110 includes a first high-potential terminal 111H, a first low-potential terminal 111L, a second high-potential terminal 112H, and a second low-potential terminal 112L.

[0030] The first module 100 includes a high-potential path 104 connecting the first high-potential terminal 111H to the positive electrode connection part 101. The first module 100 also includes a first low-potential path 105 connecting the first low-potential terminal 111L to the negative electrode connection part 102.

[0031] The first module 100 includes a second low-potential path 106 that connects the second low-potential terminal 112L to an intermediate portion of the high-potential path 104. The second high-potential 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.

[0032] Figure 2 shows an example of the first power converter 110. The first power converter 110 is a center-tapped, isolated DC-DC converter. As shown in Figures 1 and 2, the first power converter 110 includes a primary circuit 120 having a first high-potential terminal 111H and a first low-potential terminal 111L, and a secondary circuit 130 having a second high-potential terminal 112H and a second low-potential terminal 112L. In other words, the primary circuit 120 of the first power converter 110 is connected in parallel to the first battery 103. The secondary circuit 130 of the first power converter 110 is connected in series to the first battery 103.

[0033] 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. Each switch S1H, S2H, S1L, and S2L has a body diode D1H, D2H, D1L, and D2L. Note that each switch S1H, S2H, S1L, and S2L may be, for example, an IGBT. In this case, a freewheeling diode is connected in antiparallel to each switch S1H, S2H, S1L, and S2L.

[0034] The first high-potential terminal 111H is connected to the drains of the first upper arm switch S1H and the second upper arm switch S2H. 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 first low-potential terminal 111L is connected to the sources of the first and second lower arm switches S1L and S2L.

[0035] The secondary circuit 130 comprises 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. Each of the switches SW1 to SW4 also has body diodes D1 to D4.

[0036] The first terminal of reactor 132 is connected to the second high-potential terminal 112H. The second terminal of reactor 132 is connected to the drain of the second switch SW2. The source of the second switch SW2 is connected to the source of the first switch SW1. The second terminal of reactor 132 is connected to the drain of the fourth switch SW4. The source of the fourth switch SW4 is connected to the source of the third switch SW3.

[0037] Furthermore, the configuration in which the secondary circuit 130 is equipped with 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 terminal 112H is increased relative to the second low-potential terminal 112L, or a negative voltage mode, in which the voltage of the second high-potential terminal 112H is decreased relative to the second low-potential terminal 112L, after the completion of the pre-charge process.

[0038] 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. The first end of the primary coil 141 is connected to the connection point between the first upper arm switch S1H and the first lower arm switch S1L, and the second end of the primary coil 141 is connected to the connection point between the second upper arm switch S2H and the second lower arm switch S2L. The first end of the secondary coil 142 is connected to the drain of the first switch SW1, and the 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.

[0039] 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 a first high-potential terminal 111H and a first low-potential terminal 111L. The second capacitor 131 is connected to a second high-potential terminal 112H and a second low-potential terminal 112L.

[0040] As shown in Figure 1, the second power converter 210 is equipped with 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 is equipped with 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 connection relationship between each terminal 211H, 211L, 212H, 212L, 311H, 311L, 312H, 312L of the power converter corresponding to each module and the storage batteries 203, 303 corresponding to each module is the same as in the first module 100. Therefore, a detailed explanation of the connection relationship is omitted.

[0041] 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 terminals 211H, 311H and first low-potential terminals 211L, 311L, and a secondary circuit having second high-potential terminals 212H, 312H and second low-potential 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 those of the first power converter 110, so a detailed description of the second power converter 210 and the third power converter 310 is omitted.

[0042] The first power converter 110 is equipped with 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 of the first power converter 110 to turn on and off. The first drive circuit 160 charges and discharges the gates of each switch S1H, S2H, S1L, S2L, and SW1 to SW4, and is controlled by a control device 170 provided in the system 10.

[0043] Note that the second and third power converters 210 and 310 also include drive circuits 260 and 360, similar to the first power converter 110. Since 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, a detailed description of the drive circuits 260 and 360 will be omitted.

[0044] 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 the system voltage, which is the voltage between the main high potential path 20 and the main low potential path 21. The main current sensor 31 detects the current flowing through the load 23. In the example shown in FIG. 1, the main current sensor 31 detects the current flowing through a portion of the main low potential path 21 on the load 23 side rather than the connection point with 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. Note that the main current sensor 31 may detect the current flowing through a portion of the main high potential path 20 on the load 23 side rather than the connection point with the second high potential side terminals 112H, 212H, and 312H.

[0045] Each module 100, 200, and 300 includes 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 and detect the voltages of the storage batteries 103, 203, and 303. The detection values of the individual voltage sensors 155, 255, and 355 are input to the control device 170. <000009​​​As shown in FIG. 2, each of the power converters 110, 210, 310 includes a first voltage sensor 151 and a second voltage sensor 154, and a first current sensor 152 and a second current sensor 153. The first voltage sensor 151 detects a primary voltage, which is the voltage between the first high-potential side terminal 111H and the first low-potential side terminal 111L. The second voltage sensor 154 detects a secondary voltage, which is the voltage between the second high-potential side terminal 112H and the second low-potential side terminal 112L. The first current sensor 152 detects a primary current flowing through the primary side circuit 120. The second current sensor 153 detects a secondary current flowing through the secondary side circuit 130 (e.g., reactor 132). The detection values of the sensors 151, 154, 152, 153 included in each of the power converters 110, 210, 310 are input to the control device 170.

[0048] As shown in FIG. 1, the control device 170 is an electronic control unit (ECU: Electronic Control Unit) that performs various controls of the system 10, and includes a processor 171 as hardware, a storage unit 172, and a communication bus 173 that connects the processor 171 and the storage unit 172.

[0049] The storage 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, for example, a work area for temporary use by the processor 171 when the processor 171 performs processing. 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. Program information and the like for the processing described later are stored in the storage.

[0050] For example, program information stored on a non-transitional physical recording medium is installed in the storage unit 172. The recording medium is, for example, a USB memory stick, a CD-ROM, or a DVD. Also, for example, program information transmitted via a communication network, such as OTA (Over The Air), is installed in the storage unit 172.

[0051] Each module 100, 200, and 300 is equipped with switch switching units 180, 280, and 380, respectively. Hereinafter, the switch switching unit 180 of the first module 100 will be referred to as the "first switch switching unit 180," the switch switching unit 280 of the second module 200 will be referred to as the "second switch switching unit 280," and the switch switching unit 380 of the third module 300 will be referred to as the "third switch switching unit 380."

[0052] As shown in Figure 1, the first switch switching unit 180 includes a precharge switch 181, a precharge resistor 182, and a positive-side switch 183 (corresponding to the "main switch"). In this embodiment, the precharge switch 181 and the positive-side switch 183 are relays (specifically, for example, mechanical relays). The precharge switch 181 and the precharge resistor 182 are connected in series. The positive-side switch 183 is connected in parallel to the series connection of the precharge switch 181 and the precharge resistor 182. The positive-side switch 183 may be, for example, a semiconductor switching element.

[0053] The first switch switching unit 180 is provided in the portion of the high-potential path 104 that is closer to the positive electrode connection portion 101 than the portion that connects to the second low-potential path 106. This allows the first switch switching unit 180 to be included in the current flow path in both cases: when power is supplied from the first storage battery 103 to the first high-potential side terminal 111H via the high-potential path 104, and when power is supplied from the first storage battery 103 to the second low-potential side terminal 112L via the high-potential path 104 and the second low-potential path 106.

[0054] The second switch switching unit 280, like the first switch switching unit 180, includes a precharge switch 281, a precharge resistor 282, and a positive-side switch 283. The third switch switching unit 380, like the first switch switching unit 180, includes a precharge switch 381, a precharge resistor 382, ​​and a positive-side switch 383.

[0055] As shown in Figure 1, each module 100, 200, and 300 is equipped with negative-side switches 184, 284, and 384 (corresponding to the "main switch"). The negative-side switches 184, 284, and 384 are provided in the portion of the first low-potential paths 105, 205, and 305 that is closer to the negative-side connection portion 102, 202, and 302 than the portion that connects to the main low-potential path 21. In this embodiment, the negative-side switches 184, 284, and 384 are relays (specifically, for example, mechanical relays). Note that the negative-side switches 184, 284, and 384 may also be, for example, semiconductor switching elements.

[0056] Next, we will explain the control performed by the control device 170.

[0057] The control device 170 controls the precharge switches 181, 281, 381 and the positive-side switches 183, 283, 383 of each switch switching unit 180, 280, 380. The control device 170 determines whether or not a precharge command has been input from a higher-level control device (not shown). If the control device 170 determines that a precharge command has been input, it switches the precharge switches 181, 281, 381 to the ON position at the same timing while the positive-side switches 183, 283, 383 are OFF.

[0058] When the control device 170 determines that a precharge command has been input, it turns on the first switch SW1 and the third switch SW3, and turns off the second switch SW2 and the fourth switch SW4, as shown in Figure 3. This allows current to flow from the second low-potential terminal 112L to the second high-potential terminal 112H in the secondary circuit 130 of each power converter 110, 210, and 310, while preventing current from flowing from the second high-potential terminal 112H to the second low-potential terminal 112L. As a result, the generation of circulating current can be suppressed while precharging the first capacitor 121 and the second capacitor 131 and the smoothing capacitor 22 of each power converter 110, 210, and 310.

[0059] Switching the precharge switches 181, 281, and 381 to the ON position at the same time includes switching them to the ON position at the same time. Furthermore, switching the precharge switches 181, 281, and 381 to the ON position at the same time includes the time difference between the earliest ON switching timing and the latest ON switching timing of the precharge switches 181, 281, and 381 being a predetermined time difference Tα (>0). The predetermined time difference Tα is set to, for example, "0 < Tα ≤ 500 μsec", "0 < Tα ≤ 300 μsec", "0 < Tα ≤ 200 μsec", "0 < Tα ≤ 100 μsec", "50 ≤ Tα ≤ 200 μsec", or "50 ≤ Tα ≤ 150 μsec".

[0060] Figure 4 shows the procedure for the pre-charge process performed by the control device 170. This process is repeated at predetermined intervals.

[0061] In step S10, it is determined whether or not a pre-charge command has been input from the higher-level control device. If the determination in step S10 is negative, the pre-charge process is terminated. On the other hand, if it is determined that a pre-charge command has been input from the higher-level control device, the process proceeds to step S11.

[0062] In step S11, it is determined whether the situation was as initially determined to be positive in step S10 since the processing shown in Figure 4 began. If the determination in step S11 is positive, the process proceeds to step S12.

[0063] In step S12, the positive side switches 183, 283, 383, the pre-charge switches 181, 281, 381, the first to fourth switches SW1 to SW4, and the negative side switches 184, 284, 384 are turned off.

[0064] In step S13, the precharge switches 181, 281, and 381, the first and third switches SW1 and SW3, and the negative side switches 184, 284, and 384 are switched on at the same timing. This starts charging the first capacitor 121 and the second capacitor 131 and the smoothing capacitor 22 of each module 100, 200, and 300.

[0065] In this case, since the second and fourth switches SW2 and SW4 are turned off, the flow of current from the second high-potential terminals 112H, 212H, and 312H to the second low-potential terminals 112L, 212L, and 312L is blocked. As a result, the generation of circulating current can be suppressed. As the charging of the second capacitors 131 of each module 100, 200, and 300 progresses, the voltage difference between each module 100, 200, and 300, which are connected in parallel via the main high-potential path 20 and the main low-potential path 21, gradually decreases.

[0066] If the process in step S13 is completed, or if a negative determination was made in step S11, the process proceeds to step S14. In step S14, it is determined whether or not the pre-charging of the first capacitor 121 and the second capacitor 131 of each module 100, 200, and 300 has been completed. An example of the pre-charging completion determination is described below.

[0067] The maximum value of the battery voltage detected by the individual voltage sensors 155, 255, and 355 of each module 100, 200, and 300 is acquired as the maximum battery voltage Vmax. The system voltage Vc detected by the main voltage sensor 30 is also acquired. The difference between the maximum battery voltage Vmax and the system voltage Vc is calculated, and it is determined whether the absolute value of the calculated difference is less than or equal to the specified voltage Vth. If it is determined that the absolute value of the calculated difference is less than or equal to the specified voltage Vth, it is determined that precharging is complete. On the other hand, if it is determined that the absolute value of the calculated difference exceeds the specified voltage Vth, it is determined that precharging is not yet complete. Note that when the rated voltage of each battery 103, 203, and 303 is Vk, the specified voltage Vth is set to, for example, "0.05 × Vk ≤ Vth ≤ 0.15 × Vk" or "0.05 × Vk ≤ Vth ≤ 0.1 × Vk".

[0068] If it is determined in step S14 that precharging is not complete, this series of processes is terminated and the process in step S10 is executed again. On the other hand, if it is determined to be positive in step S14, the process proceeds to step S15. In step S15, the precharging switches 181, 281, and 381 are switched off, and the positive terminal switches 183, 283, and 383 are switched on. Then, the precharging process is terminated.

[0069] Figures 5 to 9 are circuit diagrams showing the state in system 10 from when a precharge command is input to the control device 170 until the precharge is completed. Note that the control device 170 and other components are omitted. To clearly show the voltage state of the first capacitor 121 and the second capacitor 131 of the power converters 110, 210, and 310, Figures 5 to 9 show the first capacitor 121 and the second capacitor 131 independently of the power converters 110, 210, and 310. In the example shown in Figures 5 to 9, the voltages of the first, second, and third storage batteries 103, 203, and 303 before the precharge process is executed are 380V, 390V, and 400V.

[0070] Figure 5 is a circuit diagram of the initial state before a precharge command is input to the control device 170. In the initial state, the precharge switches 181, 281, 381, the positive side switches 183, 283, 383, the first to fourth switches SW1 to SW4, and the negative side switches 184, 284, 384 are all turned off. As a result, no power is supplied to the load 23 from the first, second, and third storage batteries 103, 203, 303.

[0071] When a precharge command is issued and it is the first precharge, as shown in Figure 6, each precharge switch 181, 281, 381, the first switch SW1 of each power converter 110, 210, 310, the third switch SW3 of each power converter 110, 210, 310, and the negative side switches 184, 284, 384 are turned on. As a result, power is supplied from each module 100, 200, 300 to the smoothing capacitor 22. Since each battery 103, 203, 303 is connected in parallel with the primary side circuit 120, the voltage of the first capacitor 121 of each module 100, 200, 300 then rises to the voltage of the battery to which the first capacitor 121 is connected in parallel. At the point shown in Figure 6, the voltage of the first capacitor 121 and the voltage of the smoothing capacitor 22 in each module 100, 200, and 300 rise to 380V, which is the voltage of the first storage battery 103.

[0072] The voltages of the second battery 203 and the third battery 303 are higher than the system voltage (380V). Therefore, the voltages of the first capacitor 121 connected in parallel to the second battery 203, the voltage of the first capacitor 121 connected in parallel to the third battery 303, and the system voltage Vc all rise further. On the other hand, the voltage of the first module 100 (specifically, the voltage of the series connection of the first capacitor 121 and the first battery 103) is lower than the system voltage. Therefore, as shown in Figure 7, power is supplied to the second capacitor 131 of the first module 100. The voltages of the first capacitor 121 of the second module 200, the voltage of the first capacitor 121 of the third module 300, and the system voltage all rise to 390V, which is the voltage of the second battery 203. The voltage across the second capacitor 131 of the first module 100 rises to 10V, which is the difference between the voltage of the first storage battery 103 (380V) and the system voltage (390V).

[0073] The voltage of the third battery 303 is higher than the system voltage (390V). Therefore, the voltage of the first capacitor 121 connected in parallel to the third battery 303 and the system voltage rise further. On the other hand, the voltage of the first module 100 and the voltage of the second module 200 are lower than the system voltage. Therefore, as shown in Figure 8, power is supplied to the second capacitor 131 of the first module 100 and the second capacitor 131 of the second module 200. The voltage of the first capacitor 121 of the third module 300 and the system voltage rise to 400V, which is the voltage of the third battery 303. The voltage of the second capacitor 131 of the first module 100 rises to 20V, which is the difference between the voltage of the first battery 103 (380V) and the system voltage (400V). The voltage across the second capacitor 131 of the second module 200 rises to 10V, which is the difference between the voltage of the second storage battery 103 (390V) and the system voltage (400V).

[0074] When the control device 170 determines that precharging is complete, the precharge switches 181, 281, and 381 are switched to the OFF position, and the positive side switches 183, 283, and 383 are switched to the ON position, as shown in Figure 9.

[0075] According to the embodiment described above, the following effects can be obtained.

[0076] By turning off the second switch SW2 and the fourth switch SW4, the flow of current from the second high-potential terminals 112H, 212H, and 312H to the second low-potential terminals 112L, 212L, and 312L can be prevented. This suppresses the generation of circulating current.

[0077] - The generation of circulating current is suppressed by turning off the second switch SW2 and the fourth switch SW4. Therefore, even if there is a difference in the voltage of each battery 103, 203, and 303, the precharge switches 181, 281, and 381 can be switched on at the same timing. This shortens the time from when the precharge switches 181, 281, and 381 are switched on until precharging is completed.

[0078] <Modification of the First Embodiment> In step S14 of Figure 4, the method for determining whether or not precharging is complete may be changed. Specifically, the current detection values ​​of each individual current sensor 150, 250, 350 may be used to determine whether precharging is complete. In this case, the control device 170 should determine that precharging is complete if it determines that all current detection values ​​of each individual current sensor 150, 250, 350 are below a current specified value Ith that is 0 or close to 0.

[0079] As shown in Figure 10, the switch switching sections 180, 280, and 380 may be provided in the portion of the first low-potential paths 105, 205, and 305 that is closer to the negative electrode connection sections 102, 202, and 302 than to the portion connected to the main low-potential path 21. In this case, in the switch switching sections 180, 280, and 380, the negative electrode side switches 184, 284, and 384 (corresponding to the "main switch") are connected in parallel to the series connection of the precharge switches 181, 281, and 381 and the precharge resistors 182, 282, and 382.

[0080] In this case, in steps S12, S13, and S15 of Figure 4, the positive side switches 183, 283, and 383 should be read as negative side switches 184, 284, and 384, and the negative side switches 184, 284, and 384 should be read as positive side switches 183, 283, and 383.

[0081] In the configuration shown in Figure 10, using the first module 100 as an example, the current flow path can include the switch switching unit 180 in both cases: when power is supplied from the battery 103 to the first high-potential side terminal 111H via the high-potential path 104, and when power is supplied from the battery 103 to the second low-potential side terminal 112L via the high-potential path 104 and the second low-potential path 106.

[0082] <Second Embodiment> The second embodiment will now be described, focusing on the differences from the first embodiment, with reference to the drawings. In this embodiment, the configuration of each module 100, 200, and 300 has been changed, as shown in Figure 11. First, the configuration of the first module 100 will be described.

[0083] 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 connection 101 and the first high-potential side terminal 111H. The low-potential path 105 connects the negative electrode connection 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 the middle portion of the low-potential path 105 and the second high-potential side terminal 112H.

[0084] The second module 200, like the first module 100, includes a first high-potential path 204, a low-potential path 205, and a second high-potential path 207. The third module 300, like the first module 100, includes a first high-potential path 304, a low-potential path 305, and a second high-potential path 307.

[0085] The main high-potential path 20 connects to the first high-potential paths 104, 204, and 304 of each module 100, 200, and 300. The main low-potential path 21 connects to the second low-potential terminals 112L, 212L, and 312L of each module 100, 200, and 300. In other words, the secondary circuit 130 of each power converter 110, 210, and 310 is connected in series with each battery 103, 203, and 303.

[0086] The negative electrode switches 184, 284, and 384 are located in the portion of the low-potential paths 105, 205, and 305 that is on the negative electrode connection portion 102, 202, and 302 side of the connection portion with the second high-potential paths 107, 207, and 307.

[0087] The first switch switching unit 180 is provided in the portion of the first high-potential path 104 that is closer to the positive electrode connection portion 101 than the portion that connects to the main high-potential path 20. This allows the first switch switching unit 180 to be included in the current flow path in both cases: when power is supplied from the first battery 103 to the first low-potential terminal 111L via the first high-potential path 104, and when current is supplied from the second high-potential terminal 112H to the second high-potential path 107, the low-potential path 105, and the first battery 103. The control device 170 can perform pre-charge processing in the same manner as in the first embodiment.

[0088] According to the embodiment described above, the same effects as those of the first embodiment can be achieved.

[0089] <Modification of the second embodiment> As shown in Figure 12, the switch switching sections 180, 280, and 380 may be provided in the portion of the low-potential paths 105, 205, and 305 that is closer to the negative electrode connection sections 102, 202, and 302 than the portion that connects to the second high-potential paths 107, 207, and 307. In this case, in the switch switching sections 180, 280, and 380, the negative electrode side switches 184, 284, and 384 (corresponding to the "main switch") are connected in parallel to the series connection of the pre-charge switches 181, 281, and 381 and the pre-charge resistors 182, 282, and 382.

[0090] As a result, the switch switching unit 180 can be included in the current flow path in both cases: when power is supplied from the first battery 103 to the first high-potential side terminal 111H via the first high-potential path 104, and when power is supplied from the first battery 103 to the second low-potential side terminal 112L via the main high-potential path 20 and the main low-potential path 21.

[0091] In this case, in steps S12, S13, and S15 of Figure 4, the positive side switches 183, 283, and 383 should be read as negative side switches 184, 284, and 384, and the negative side switches 184, 284, and 384 should be read as positive side switches 183, 283, and 383.

[0092] <Third Embodiment> The third embodiment will now be described, focusing on the differences from the first and second embodiments, with reference to the drawings. In this embodiment, the configuration of the secondary circuit 130 has been changed, as shown in Figure 13. The secondary circuit 130 includes a first switch SA and a second switch SB. The first switch SA and the second switch SB are semiconductor switching elements, similar to the first embodiment, and specifically N-channel MOSFETs. Each switch SA and SB has body diodes DA and DB.

[0093] The drain of the first switch SA and the drain of the second switch SB are connected to the second end of the reactor 132. The first end of the secondary coil 142 is connected to the source of the first switch SA. The second end of the secondary coil 142 is connected to the source of the second switch SB. In this embodiment, the secondary circuit 130 is configured to be able to execute only the positive voltage mode out of the positive voltage mode and negative voltage mode.

[0094] When the control device 170 determines that a precharge command has been input, it turns off the first switch SA and the second switch SB. This allows current to flow from the second low-potential terminal 112L to the second high-potential terminal 112H in the secondary circuit 130 of each power converter 110, 210, and 310, while preventing current from flowing from the second high-potential terminal 112H to the second low-potential terminal 112L. As a result, the generation of circulating current can be suppressed while precharging the first capacitor 121 and the second capacitor 131 and the smoothing capacitor 22 of each power converter 110, 210, and 310.

[0095] Figure 14 shows the procedure for the pre-charge process performed by the control device 170. This process is repeated at predetermined intervals. In Figure 14, the same reference numerals are used for processes that are the same as those shown in Figure 4 for convenience. The following explanation of the process in Figure 14 will focus on the differences from Figure 4.

[0096] If a positive result is obtained in step S11, the process proceeds to step S16. In step S16, the positive side switches 183, 283, 383, the pre-charge switches 181, 281, 381, the first and second switches SA, SB, and the negative side switches 184, 284, 384 are turned off.

[0097] In step S17, the pre-charge switches 181, 281, and 381 and the negative terminal switches 184, 284, and 384 are switched on at the same time. This starts charging the first capacitors 121 and 2 capacitors 131 and the smoothing capacitor 22 of each module 100, 200, and 300.

[0098] In this case, since the first and second switches SA and SB are turned off, the flow of current from the second high-potential terminals 112H, 212H, and 312H to the second low-potential terminals 112L, 212L, and 312L is blocked. As a result, the generation of circulating current can be suppressed. As the charging of the second capacitors 131 of each module 100, 200, and 300 progresses, the voltage difference between each module 100, 200, and 300, which are connected in parallel via the main high-potential path 20 and the main low-potential path 21, gradually decreases.

[0099] <Other Embodiments> Each of the above embodiments may be implemented with the following modifications.

[0100] The configuration of the first to fourth switches SW1 to SW4 in the secondary circuit 130 of the first embodiment may be changed as shown in Figure 15. Specifically, the first switch SW1 and the second switch SW2 may be swapped, and the fourth switch SW4 and the third switch SW3 may be swapped. 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.

[0101] Furthermore, when the control device 170 determines that a pre-charge command has been input, it turns on the first switch SW1 and the third switch SW3, and turns off the second switch SW2 and the fourth switch SW4.

[0102] As shown in Figure 16, the first to fourth switches Q1 to Q4 in the secondary circuit 130 may be N-channel IGBTs instead of N-channel MOSFETs. In this case, freewheeling diodes DD1 to DD4 are connected in antiparallel to each of the switches Q1 to Q4.

[0103] The collector of the second switch Q2 is connected to the second terminal of reactor 132. The emitter of the first switch Q1 is connected to the emitter of the second switch Q2. The collector of the fourth switch Q4 is connected to the second terminal of reactor 132. The emitter of the third switch Q3 is connected to the emitter of the fourth switch Q4. The first terminal of the secondary coil 142 is connected to the collector of the first switch Q1, and the second terminal of the secondary coil 142 is connected to the collector of the third switch Q3.

[0104] Furthermore, when the control device 170 determines that a pre-charge command has been input, it turns on the first switch Q1 and the third switch Q3, and turns off the second switch Q2 and the fourth switch Q4.

[0105] As shown in Figure 17, the first and second switches QA and QB in the secondary circuit 130 may be N-channel IGBTs instead of N-channel MOSFETs. In this case, freewheeling diodes DDA and DDB are connected in antiparallel to each of the switches QA and QB.

[0106] The collector of the first switch QA is connected to the second terminal of the reactor 132. The first terminal of the secondary coil 142 is connected to the emitter of the first switch QA. The collector of the second switch QB is connected to the second terminal of the reactor 132. The second terminal of the secondary coil 142 is connected to the emitter of the second switch QB.

[0107] Furthermore, if the control device 170 determines that a pre-charge command has been input, it turns off the first switch QA and the second switch QB.

[0108] - The process shown in Figure 4 above may be amended by the process in step S20, as shown in Figure 18. Specifically, if the process in step S13 is completed, or if a negative determination is made in step S11, the process proceeds to step S20. In step S20, in each module 100, 200, and 300, the switching control of the first and second upper arm switches S1H, S2H and the first and second lower arm switches S1L, S2L provided in the primary side circuit 120 is performed in order to transmit power from the primary side circuit 120 to the secondary side circuit 130 via the isolation transformer 140. This promotes the charging of the smoothing capacitor 22.

[0109] Furthermore, the process in step S20 may also be applied to the pre-charge process shown in Figure 14.

[0110] The configuration of the secondary circuit 130 may be, for example, the configuration shown in Figure 19. Below, Figure 19 will be described with reference to the drawing, focusing on the differences from the first embodiment. The secondary circuit 130 comprises a first switch section R1 and a second switch section R2.

[0111] The first end of the secondary coil 142 and the second low-potential terminal 112L are connected by a first switch section R1. The second end of the secondary coil 142 and the second low-potential 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 antiparallel 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 antiparallel to the second H switch RH2. The secondary circuit 130 shown in Figure 19 is configured to be selectable and executable in either a positive voltage mode or a negative voltage mode.

[0112] Furthermore, when the control device 170 determines that a pre-charge command has been input, it turns off the first H switch RH1 and the second H switch RH2, and turns on the first L switch RL1 and the second L switch RL2.

[0113] The secondary circuit 130 is not limited to a center-tapped circuit, but may be, for example, a full-bridge circuit as shown in Figure 20. The secondary 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 and the source of the first L switch UL1 are connected. The second switch section U2 includes a series connection of a second H switch UH2 and a second L switch UL2, with their sources 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, with their sources 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, with their sources connected to each other. Each switch UH1, UL1, UH2, UL2, UH3, UL3, UH4, UL4 has a body diode DH1, DL1, DH2, DL2, DH3, DL3, DH4, DL4.

[0114] The second end of reactor 132 is connected to the second low-potential terminal 112L via a series connection of the first switch section U1 and the second switch section U2. The second end of reactor 132 is also connected to the second low-potential terminal 112L via a series connection of the third switch section U3 and the fourth switch section U4. The first end of secondary coil 142 is connected to the connection point of the first switch section U1 and the second switch section U2. The second end of secondary coil 142 is connected to the connection point of the third switch section U3 and the fourth switch section U4.

[0115] In the configuration shown in Figure 20, in step S12 of Figure 4, the first to fourth switches SW1 to SW4 should be replaced with switches UH1, UL1, UH2, UL2, UH3, UL3, UH4, and UL4, respectively. Also, in step S13, the first and third switches SW1 and SW3 should be replaced with the first L switch UL1, the second L switch UL2, the third L switch UL3, and the fourth L switch UL4.

[0116] The loads connected to the system are not limited to the inverter 23a and the rotating electric machine 23b, but may also include a DC-DC converter, an external charger, a heater, etc.

[0117] The power converter is not limited to those described in Figure 2; for example, non-isolated DC-DC converters such as resonant DC-DC converters and buck converters can be used.

[0118] System 10 may be a combination of at least two modules from among the modules described in the first embodiment, the modules described in the second embodiment, and the modules described in the third embodiment.

[0119] The number of modules in system 10 may be two or four or more. In this case, each module may be configured in the same way as the modules described in the first to third embodiments, or in the same way as the modules described in the modified version of the first embodiment, the modified version of the second embodiment, and other embodiments.

[0120] The energy storage unit in each module is not limited to a battery; for example, it may include a large-capacity electric double-layer capacitor, or both a battery and an electric double-layer capacitor. Furthermore, the energy storage unit may also be a fuel cell.

[0121] The system 10 is not limited to being mounted on a vehicle; for example, it may be mounted on an aircraft or a ship. If the ship is an aircraft, the rotating electric motor will be the aircraft's power source for flight, and if the ship is a ship, the rotating electric motor will be the ship's power source for navigation. Furthermore, the system 10 is not limited to being mounted on a ship; it can also be used as a stationary power source.

[0122] In this disclosure or claims, the term "processor" means one or more hardware processors configured to execute processing defined by computer program code (i.e., one or more instructions of a computer program) contained in a computer program by reading the computer program code each time. In other words, a "processor" is a hardware device that executes one or more programmed processes. Therefore, computer program code can also be said to be software that can define the processing of the processor according to its content. A "processor" can be a general-purpose or specific-purpose processor, and may be, but is not limited to, a CPU, microprocessor, GPU, and DFP (Data Flow Processor).

[0123] In this disclosure or claims, the term “memory” means one or more hardware memories that are non-transitional tangible recording media configured to record computer program code and / or data in a manner accessible from a processor. “Memory” can be implemented by memory technology such as SRAM, SDRAM, non-volatile / flash type memory, or other types of memory. The computer program code that constitutes the program is recorded in memory and executed by a processor, thereby enabling the processor to perform the various functions described above.

[0124] In this disclosure or claims, the term “circuit” refers to one or more logic circuits as hardware, configured to perform specific processing defined by a pre-designed circuit configuration. In other words (and, in contrast to “processor”), “circuit” in this disclosure or claims refers to a hardware device that performs specific processing based on a circuit configuration, rather than processing defined by software such as the computer program code described above. For example, “circuit” may include custom ICs such as ASICs (Application Specific Integrated Circuits) and FPGAs (Field Programmable Gate Arrays) designed with Hardware Description Language (HDL). That is, “circuit” in this disclosure or claims includes all hardware circuits except for the processors described above that perform processing by reading computer program code.

[0125] In this disclosure or claims, the expression "at least one of the circuit and processor" should be interpreted as disjunctive (logical OR) and not as "at least one circuit and at least one processor." Therefore, in this disclosure or claims, "at least one of the circuit and processor causes the control device to perform functions" includes cases where the circuit alone causes the control device to perform all functions. Also, "at least one of the circuit and processor causes the control device to perform functions" includes cases where the processor alone causes the control device to perform all functions. Furthermore, "at least one of the circuit and processor causes the control device to perform functions" includes cases where the circuit causes the control device to perform some functions and the processor causes the control device to perform the remaining functions. In the last example, for example, if the control device performs functions A to C, functions A and B may be implemented by the circuit, and the remaining function C may be implemented by the processor.

[0126] The following describes characteristic configurations extracted from each of the embodiments described above. [Configuration 1] A system (10) comprising a plurality of modules (100, 200, 300) having positive electrode connection parts (101, 201, 301) connectable to the positive electrode terminals of the energy storage units (103, 203, 303), negative electrode connection parts (102, 202, 302) connectable to the negative electrode terminals of the energy storage units, and power converters (110, 210, 310), wherein the power converter of each module includes a primary circuit (120) including a first high-potential side terminal (111H, 211H, 311H), a first low-potential side terminal (111L, 211L, 311L), and a first capacitor (121) connecting the first high-potential side terminal and the first low-potential side terminal, The module comprises: a secondary circuit (130) including second high-potential terminals (112H, 212H, 312H), second low-potential terminals (112L, 212L, 312L), and a second capacitor (131) connecting the second high-potential terminals and the second low-potential terminals; an isolation transformer (140) connecting the primary circuit and the secondary circuit; each module having: a high-potential path (104, 204, 304) connecting the positive electrode connection and the first high-potential terminal; a first low-potential path (105, 205, 305) connecting the negative electrode connection and the first low-potential terminal; a second low-potential path (106, 206, 306) connecting the middle portion of the high-potential path and the second low-potential terminal; and a main high-potential path (20) connecting the second high-potential terminal of each module. Each module comprises: a main low-potential path (21) connecting the first low-potential paths of each module; and in each module, a switch switching section (180, 280, 380) provided in the portion of the high-potential path closer to the positive electrode connection portion than the connection portion with the second low-potential path, or in the portion of the first low-potential path closer to the negative electrode connection portion than the connection portion with the main low-potential path, wherein the switch switching section comprises a series connection of pre-charge switches (181, 281, 381) and pre-charge resistors (182, 282, 382), and a main switch (183, 283, 383, 184, 284,A system comprising a parallel connection with 384), wherein the secondary circuit of each module has the function of allowing current to flow from the second low-potential terminal to the second high-potential terminal and preventing current from flowing from the second high-potential terminal to the second low-potential terminal. [Configuration 2] A system (10) comprising a plurality of modules (100, 200, 300) having positive terminal connectors (101, 201, 301) connectable to the positive terminals of energy storage units (103, 203, 303), negative terminal connectors (102, 202, 302) connectable to the negative terminals of the energy storage units, and power converters (110, 210, 310), wherein the power converter of each module includes a primary circuit (120) including a first high-potential side terminal (111H, 211H, 311H), a first low-potential side terminal (111L, 211L, 311L), and a first capacitor (121) connecting the first high-potential side terminal and the first low-potential side terminal, The module comprises: a secondary circuit (130) including second high-potential terminals (112H, 212H, 312H), second low-potential terminals (112L, 212L, 312L), and a second capacitor (131) connecting the second high-potential terminals and the second low-potential terminals; an isolation transformer (140) connecting the primary circuit and the secondary circuit; each module having: a first high-potential path (104, 204, 304) connecting the positive electrode connection and the first high-potential terminal; a low-potential path (105, 205, 305) connecting the negative electrode connection and the first low-potential terminal; a second high-potential path (107, 207, 307) connecting the middle portion of the low-potential path and the second high-potential terminal; and a main high-potential path (20) connecting the first high-potential path of each module. The module comprises: a main low-potential path (21) connecting the second low-potential terminal of each module; and a switch switching section (180, 280, 380) provided in each module in the portion of the first high-potential path closer to the positive terminal connection than the connection portion with the main high-potential path, or in the portion of the low-potential path closer to the negative terminal connection than the connection portion with the second high-potential path, wherein the switch switching section comprises a precharge switch (181, 281, 381) and a precharge resistor (182,A system comprising a series connection of modules 282 and 382, ​​and a parallel connection of main switches (183, 283, 383, 184, 284, 384), wherein the secondary circuit of each module has the function of allowing current to flow from the second low-potential terminal to the second high-potential terminal and preventing current from flowing from the second high-potential terminal to the second low-potential terminal. [Configuration 3] The system according to Configuration 1 or 2, further comprising a control device (170), wherein when the control device determines that a pre-charge command has been input, it switches the pre-charge switches of each module to ON at the same timing while the main switches of each module are OFF. [Configuration 4] The system according to Configuration 3, further comprising a smoothing capacitor (22) connecting the main high-potential path and the main low-potential path, wherein when the control device determines that the precharge command has been input, it controls the switching of the primary circuit of each module in order to transmit power from the primary circuit to the secondary circuit via the isolation transformer in each module. [Configuration 5] The system according to Configuration 3 or 4, wherein when the control device determines that the precharging of the first capacitor and the second capacitor of each module is complete, it switches the precharge switch to the off position and switches the main switch to the on position in each module. [Configuration 6] The secondary circuit comprises secondary switches (SW1 to SW4, Q1 to Q4, R1, R2, UH1 to UH4, UL1 to UL4), a reactor (132), and the isolation transformer comprises a primary coil (141) connected to the primary circuit, and a secondary coil (142) connected to the secondary circuit, and the secondary circuit is configured to be able to select and execute either a positive voltage mode in which the voltage at the second high potential terminal is higher than the voltage at the second low potential terminal, or a negative voltage mode in which the voltage at the second low potential terminal is higher than the voltage at the second high potential terminal, as described in any one of Configurations 1 to 5. [Configuration 7] The secondary switches comprise a first switch (SW1, Q1), a second switch (SW2, Q2), a third switch (SW3, Q3), and a fourth switch (SW4,Q4) The secondary coil (142) has a first end, a second end and a center tap (143), the center tap is connected to the second low-potential terminal, the first end of the reactor is connected to the second high-potential terminal, the first end of the secondary coil and the second end of the reactor are connected in series with the first switch and the second switch, the second end of the secondary coil and the second end of the reactor are connected in series with the third switch and the fourth switch, a first diode (D1, DD1) is connected in parallel with the first switch and its cathode is connected toward the first end of the secondary coil, a second diode (D2, DD2) is connected in parallel with the second switch and its cathode is connected toward the second end of the reactor, a third diode (D3, DD3) is connected in parallel with the third switch and its cathode is connected toward the second end of the secondary coil, The system according to configuration 6, comprising: a fourth diode (D4, DD4) connected in parallel to the fourth switch and having its cathode directed toward the second end of the reactor. [Configuration 8] The isolation transformer comprises: a primary coil (141) connected to the primary circuit; a secondary coil (142) having a first end, a second end and a center tap (143); a reactor (132) having a first end and a second end connected to the second low-potential terminal and the second high-potential terminal; a first switch (SA, QA) connecting the first end of the secondary coil and the second end of the reactor; a second switch (SB, QB) connecting the second end of the secondary coil and the second end of the reactor; a first diode (DA, DDA) connected in parallel to the first switch with its cathode facing the second end of the reactor; and a second diode (DB, DDB) connected in parallel to the second switch with its cathode facing the second end of the reactor, as described in Configuration 1 or 2.

[0127] This disclosure is described in accordance with the embodiments, but it is understood that this disclosure is not limited to such embodiments or structures. This disclosure also includes various modifications and variations within the equivalence. In addition, various combinations and forms, as well as other combinations and forms that include only one, more, or fewer of those elements, fall within the scope and concept of this disclosure.

Claims

1. In a system (10) comprising a plurality of modules (100, 200, 300) having positive terminal connectors (101, 201, 301) connectable to the positive terminals of energy storage units (103, 203, 303), negative terminal connectors (102, 202, 302) connectable to the negative terminals of the energy storage units, and power converters (110, 210, 310), the power converter of each module includes a primary circuit (120) including a first high-potential side terminal (111H, 211H, 311H), a first low-potential side terminal (111L, 211L, 311L), and a first capacitor (121) connecting the first high-potential side terminal and the first low-potential side terminal, The module comprises: a secondary circuit (130) including second high-potential terminals (112H, 212H, 312H), second low-potential terminals (112L, 212L, 312L), and a second capacitor (131) connecting the second high-potential terminals and the second low-potential terminals; an isolation transformer (140) connecting the primary circuit and the secondary circuit; each module having: a high-potential path (104, 204, 304) connecting the positive electrode connection and the first high-potential terminal; a first low-potential path (105, 205, 305) connecting the negative electrode connection and the first low-potential terminal; a second low-potential path (106, 206, 306) connecting the middle portion of the high-potential path and the second low-potential terminal; and a main high-potential path (20) connecting the second high-potential terminal of each module. Each module comprises: a main low-potential path (21) connecting the first low-potential paths of each module; and in each module, a switch switching section (180, 280, 380) provided in the portion of the high-potential path closer to the positive electrode connection portion than the connection portion with the second low-potential path, or in the portion of the first low-potential path closer to the negative electrode connection portion than the connection portion with the main low-potential path, wherein the switch switching section comprises a series connection of pre-charge switches (181, 281, 381) and pre-charge resistors (182, 282, 382), and a main switch (183, 283, 383, 184, 284,A system that is connected in parallel with (384), wherein the secondary circuit of each module has the function of allowing current to flow from the second low-potential terminal to the second high-potential terminal and preventing current from flowing from the second high-potential terminal to the second low-potential terminal.

2. In a system (10) comprising a plurality of modules (100, 200, 300) having positive terminal connectors (101, 201, 301) connectable to the positive terminals of energy storage units (103, 203, 303), negative terminal connectors (102, 202, 302) connectable to the negative terminals of the energy storage units, and power converters (110, 210, 310), the power converter of each module includes a primary circuit (120) including a first high-potential side terminal (111H, 211H, 311H), a first low-potential side terminal (111L, 211L, 311L), and a first capacitor (121) connecting the first high-potential side terminal and the first low-potential side terminal, The module comprises: a secondary circuit (130) including second high-potential terminals (112H, 212H, 312H), second low-potential terminals (112L, 212L, 312L), and a second capacitor (131) connecting the second high-potential terminals and the second low-potential terminals; an isolation transformer (140) connecting the primary circuit and the secondary circuit; each module having: a first high-potential path (104, 204, 304) connecting the positive electrode connection and the first high-potential terminal; a low-potential path (105, 205, 305) connecting the negative electrode connection and the first low-potential terminal; a second high-potential path (107, 207, 307) connecting the middle portion of the low-potential path and the second high-potential terminal; and a main high-potential path (20) connecting the first high-potential path of each module. The module comprises a main low-potential path (21) connecting the second low-potential terminal of each module, and a switch switching section (180, 280, 380) provided in each module in the portion of the first high-potential path closer to the positive terminal connection than the connection portion with the main high-potential path, or in the low-potential path closer to the negative terminal connection than the connection portion with the second high-potential path, wherein the switch switching section comprises a series connection of pre-charge switches (181, 281, 381) and pre-charge resistors (182, 282, 382), and a main switch (183, 283, 383, 184, 284,A system that is connected in parallel with (384), wherein the secondary circuit of each module has the function of allowing current to flow from the second low-potential terminal to the second high-potential terminal and preventing current from flowing from the second high-potential terminal to the second low-potential terminal.

3. The system according to claim 1 or 2, comprising a control device (170), wherein when the control device determines that a precharge command has been input, it switches the precharge switches of each module to the ON position at the same timing while the main switches of each module are OFF.

4. The system according to claim 3, further comprising a smoothing capacitor (22) connecting the main high-potential path and the main low-potential path, wherein when the control device determines that the precharge command has been input, it controls the switching of the primary circuit of each module in order to transmit power from the primary circuit to the secondary circuit via the isolation transformer in each module.

5. The system according to claim 3, wherein when the control device determines that the pre-charging of the first capacitor and the second capacitor of each module is complete, it switches the pre-charge switch to the OFF position and the main switch to the ON position in each module.

6. The system according to claim 1 or 2, wherein the secondary circuit comprises secondary switches (SW1 to SW4, Q1 to Q4, R1, R2, UH1 to UH4, UL1 to UL4) and a reactor (132), and the isolation transformer comprises a primary coil (141) connected to the primary circuit and a secondary coil (142) connected to the secondary circuit, and the secondary circuit is configured to select and execute either a positive voltage mode in which the voltage at the second high potential terminal is higher than the voltage at the second low potential terminal, or a negative voltage mode in which the voltage at the second low potential terminal is higher than the voltage at the second high potential terminal.

7. The secondary switches are a first switch (SW1, Q1), a second switch (SW2, Q2), a third switch (SW3, Q3), and a fourth switch (SW4, Q4), the secondary coil (142) has a first end, a second end, and a center tap (143), the center tap is connected to the second low-potential terminal, the first end of the reactor is connected to the second high-potential terminal, the first end of the secondary coil and the second end of the reactor are connected in series with the first switch and the second switch, the second end of the secondary coil and the second end of the reactor are connected in series with the third switch and the fourth switch, and a first diode (D1, DD1) is connected in parallel to the first switch with its cathode facing the first end of the secondary coil, The system according to claim 6, comprising: a second diode (D2, DD2) connected in parallel to the second switch with its cathode facing the second end of the reactor; a third diode (D3, DD3) connected in parallel to the third switch with its cathode facing the second end of the secondary coil; and a fourth diode (D4, DD4) connected in parallel to the fourth switch with its cathode facing the second end of the reactor.

8. The isolation transformer comprises: a primary coil (141) connected to the primary circuit; a secondary coil (142) having a first end, a second end and a center tap (143); a reactor (132) having a first end and a second end connected to the second low-potential terminal and the second high-potential terminal; a first switch (SA, QA) connecting the first end of the secondary coil and the second end of the reactor; a second switch (SB, QB) connecting the second end of the secondary coil and the second end of the reactor; a first diode (DA, DDA) connected in parallel to the first switch with its cathode facing the second end of the reactor; and a second diode (DB, DDB) connected in parallel to the second switch with its cathode facing the second end of the reactor.

9. In a program applied to a system (10) comprising a plurality of modules (100, 200, 300) having positive terminal connectors (101, 201, 301) connectable to the positive terminals of energy storage units (103, 203, 303), negative terminal connectors (102, 202, 302) connectable to the negative terminals of the energy storage units, and power converters (110, 210, 310), the power converter of each module comprises a primary circuit (120) including a first high-potential side terminal (111H, 211H, 311H), a first low-potential side terminal (111L, 211L, 311L), and a first capacitor (121) connecting the first high-potential side terminal and the first low-potential side terminal, The system comprises: a secondary circuit (130) including second high-potential terminals (112H, 212H, 312H), second low-potential terminals (112L, 212L, 312L), and a second capacitor (131) connecting the second high-potential terminals and the second low-potential terminals; and an isolation transformer (140) connecting the primary circuit and the secondary circuit, wherein each module includes: high-potential paths (104, 204, 304) connecting the positive electrode connection and the first high-potential terminal; a first low-potential path (105, 205, 305) connecting the negative electrode connection and the first low-potential terminal; and a second low-potential path (106, 206, 306) connecting the middle portion of the high-potential path and the second low-potential terminal. The module comprises: a main high-potential path (20) connecting the second high-potential terminal of each module; a main low-potential path (21) connecting the first low-potential path of each module; and in each module, a switch switching section (180, 280, 380) provided in the portion of the high-potential path closer to the positive terminal connection than the portion connecting to the second low-potential path, or in the portion of the first low-potential path closer to the negative terminal connection than the portion connecting to the main low-potential path, wherein the switch switching section comprises a series connection of pre-charge switches (181, 281, 381) and pre-charge resistors (182, 282, 382), and a main switch (183, 283, 383, 184, 284,A parallel connection with (384), wherein the secondary circuit of each module has the function of allowing current to flow from the second low-potential terminal to the second high-potential terminal and preventing current from flowing from the second high-potential terminal to the second low-potential terminal, and a program that, when it determines that a precharge command has been input to at least one of the circuit and the processor (171), causes the main switch of each module to be turned on at the same timing while the main switch of each module is turned off.

10. A system control method applicable to a system (10) comprising a plurality of modules (100, 200, 300) having positive terminal connectors (101, 201, 301) connectable to the positive terminals of energy storage units (103, 203, 303), negative terminal connectors (102, 202, 302) connectable to the negative terminals of the energy storage units, and power converters (110, 210, 310), wherein the power converter of each module includes a primary circuit (120) including a first high-potential side terminal (111H, 211H, 311H), a first low-potential side terminal (111L, 211L, 311L), and a first capacitor (121) connecting the first high-potential side terminal and the first low-potential side terminal, The system comprises: a secondary circuit (130) including second high-potential terminals (112H, 212H, 312H), second low-potential terminals (112L, 212L, 312L), and a second capacitor (131) connecting the second high-potential terminals and the second low-potential terminals; and an isolation transformer (140) connecting the primary circuit and the secondary circuit, wherein each module includes: high-potential paths (104, 204, 304) connecting the positive electrode connection and the first high-potential terminal; a first low-potential path (105, 205, 305) connecting the negative electrode connection and the first low-potential terminal; and a second low-potential path (106, 206, 306) connecting the middle portion of the high-potential path and the second low-potential terminal. The module comprises: a main high-potential path (20) connecting the second high-potential terminal of each module; a main low-potential path (21) connecting the first low-potential path of each module; and in each module, a switch switching section (180, 280, 380) provided in the portion of the high-potential path closer to the positive terminal connection than the portion connecting to the second low-potential path, or in the portion of the first low-potential path closer to the negative terminal connection than the portion connecting to the main low-potential path, wherein the switch switching section comprises a series connection of pre-charge switches (181, 281, 381) and pre-charge resistors (182, 282, 382), and a main switch (183, 283, 383, 184, 284,A parallel connection with (384), wherein the secondary circuit of each module has the function of allowing current to flow from the second low-potential terminal to the second high-potential terminal and preventing current from flowing from the second high-potential terminal to the second low-potential terminal, and a system control method which, when it determines that a precharge command has been input to at least one of the circuit and the processor (171), causes the main switch of each module to be turned off and the precharge switch of each module to be turned on at the same timing.

11. In a program applied to a system (10) comprising a plurality of modules (100, 200, 300) having positive terminal connectors (101, 201, 301) connectable to the positive terminals of energy storage units (103, 203, 303), negative terminal connectors (102, 202, 302) connectable to the negative terminals of the energy storage units, and power converters (110, 210, 310), the power converter of each module comprises a primary circuit (120) including a first high-potential side terminal (111H, 211H, 311H), a first low-potential side terminal (111L, 211L, 311L), and a first capacitor (121) connecting the first high-potential side terminal and the first low-potential side terminal, The system comprises: a secondary circuit (130) including second high-potential terminals (112H, 212H, 312H), second low-potential terminals (112L, 212L, 312L), and a second capacitor (131) connecting the second high-potential terminals and the second low-potential terminals; and an isolation transformer (140) connecting the primary circuit and the secondary circuit, wherein each module includes: a first high-potential path (104, 204, 304) connecting the positive electrode connection and the first high-potential terminal; a low-potential path (105, 205, 305) connecting the negative electrode connection and the first low-potential terminal; and a second high-potential path (107, 207, 307) connecting the middle portion of the low-potential path and the second high-potential terminal. Each module comprises: a main high-potential path (20) connecting the first high-potential paths of each module; a main low-potential path (21) connecting the second low-potential terminals of each module; and in each module, a switch switching section (180, 280, 380) provided in the portion of the first high-potential path closer to the positive terminal connection than the connection portion with the main high-potential path, or in the portion of the low-potential path closer to the negative terminal connection than the connection portion with the second high-potential path, wherein the switch switching section comprises a series connection of pre-charge switches (181, 281, 381) and pre-charge resistors (182, 282, 382), and a main switch (183, 283, 383, 184, 284,A parallel connection with (384), wherein the secondary circuit of each module has the function of allowing current to flow from the second low-potential terminal to the second high-potential terminal and preventing current from flowing from the second high-potential terminal to the second low-potential terminal, and a program that, when it determines that a precharge command has been input to at least one of the circuit and the processor (171), causes the main switch of each module to be turned on at the same timing while the main switch of each module is turned off.

12. The isolation transformer comprises a primary coil (141) connected to the primary circuit, and a secondary coil (142) having a first end, a second end and a center tap (143), wherein the center tap is connected to the second low-potential terminal, and the secondary circuit comprises a reactor (132) having a first end and a second end connected to the second high-potential terminal, a series connection of a first switch (SW1, Q1) and a second switch (SW2, Q2) connecting the first end of the secondary coil and the second end of the reactor, a series connection of a third switch (SW3, Q3) and a fourth switch (SW4, Q4) connecting the second end of the secondary coil and the second end of the reactor, and a first diode (D1, DD1) connected in parallel to the first switch with its cathode facing the first end of the secondary coil. The program according to claim 9 or 11, comprising: a second diode (D2, DD2) connected in parallel to the second switch with its cathode facing the second end of the reactor; a third diode (D3, DD3) connected in parallel to the third switch with its cathode facing the second end of the secondary coil; and a fourth diode (D4, DD4) connected in parallel to the fourth switch with its cathode facing the second end of the reactor, wherein when at least one of the circuit and the processor determines that the precharge command has been input, it causes the first switch and the third switch to be turned on and the second switch and the fourth switch to be turned off.

13. A system control method applicable to a system (10) comprising a plurality of modules (100, 200, 300) having positive terminal connectors (101, 201, 301) connectable to the positive terminals of energy storage units (103, 203, 303), negative terminal connectors (102, 202, 302) connectable to the negative terminals of the energy storage units, and power converters (110, 210, 310), wherein the power converter of each module includes a primary circuit (120) including a first high-potential side terminal (111H, 211H, 311H), a first low-potential side terminal (111L, 211L, 311L), and a first capacitor (121) connecting the first high-potential side terminal and the first low-potential side terminal, The system comprises: a secondary circuit (130) including second high-potential terminals (112H, 212H, 312H), second low-potential terminals (112L, 212L, 312L), and a second capacitor (131) connecting the second high-potential terminals and the second low-potential terminals; and an isolation transformer (140) connecting the primary circuit and the secondary circuit, wherein each module includes: a first high-potential path (104, 204, 304) connecting the positive electrode connection and the first high-potential terminal; a low-potential path (105, 205, 305) connecting the negative electrode connection and the first low-potential terminal; and a second high-potential path (107, 207, 307) connecting the middle portion of the low-potential path and the second high-potential terminal. Each module comprises: a main high-potential path (20) connecting the first high-potential paths of each module; a main low-potential path (21) connecting the second low-potential terminals of each module; and in each module, a switch switching section (180, 280, 380) provided in the portion of the first high-potential path closer to the positive terminal connection than the connection portion with the main high-potential path, or in the portion of the low-potential path closer to the negative terminal connection than the connection portion with the second high-potential path, wherein the switch switching section comprises a series connection of pre-charge switches (181, 281, 381) and pre-charge resistors (182, 282, 382), and a main switch (183, 283, 383, 184, 284,A parallel connection with (384), wherein the secondary circuit of each module has the function of allowing current to flow from the second low-potential terminal to the second high-potential terminal and preventing current from flowing from the second high-potential terminal to the second low-potential terminal, and a system control method which, when it determines that a precharge command has been input to at least one of the circuit and the processor (171), causes the main switch of each module to be turned off and the precharge switch of each module to be turned on at the same timing.

14. The isolation transformer comprises a primary coil (141) connected to the primary circuit, and a secondary coil (142) having a first end, a second end and a center tap (143), wherein the center tap is connected to the second low-potential terminal, and the secondary circuit comprises a reactor (132) having a first end and a second end connected to the second high-potential terminal, a series connection of a first switch (SW1, Q1) and a second switch (SW2, Q2) connecting the first end of the secondary coil and the second end of the reactor, a series connection of a third switch (SW3, Q3) and a fourth switch (SW4, Q4) connecting the second end of the secondary coil and the second end of the reactor, and a first diode (D1, DD1) connected in parallel to the first switch with its cathode facing the first end of the secondary coil. A system control method according to claim 10 or 13, comprising: a second diode (D2, DD2) connected in parallel to the second switch with its cathode facing the second end of the reactor; a third diode (D3, DD3) connected in parallel to the third switch with its cathode facing the second end of the secondary coil; and a fourth diode (D4, DD4) connected in parallel to the fourth switch with its cathode facing the second end of the reactor, wherein when at least one of the circuit and the processor determines that the precharge command has been input, it is instructed to turn on the first switch and the third switch and turn off the second switch and the fourth switch.

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