Power System

Abstract

To provide a power supply system that outputs AC power by using battery strings.SOLUTION: A power supply system 1 includes: a first power supply circuit 2 that converts DC power of a first DC sweep unit 10 including a battery string St1 into AC power with a first inverter 50 and outputs the AC power; and an AC sweep unit 3 that includes a U-phase battery string St4, a V-phase battery string St6, and a W-phase battery string St8 that are Y-connected. An energy density of batteries B included in the U-phase battery string St4, the V-phase battery string St6, and the W-phase battery string St8 is higher than that of batteries B included in the string St1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a power supply system, and more particularly to a power supply system using multiple battery strings. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2018-074709 (Patent Document 1) discloses a control circuit that controls a battery string. The battery string includes a plurality of battery module circuits (battery circuit modules) connected to each other. Each battery circuit module included in the battery string includes a battery, a first switch connected in parallel to the battery, a second switch connected in series to the battery, and a first output terminal and a second output terminal to which the battery voltage is applied when the first switch is in an OFF state and the second switch is in an ON state. The control circuit can adjust the output voltage of the battery string to a desired magnitude by controlling the first switch and the second switch of each battery circuit module included in the battery string. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-074709 A Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 discloses a power supply system that outputs DC power using a battery string as described above. However, Patent Document 1 does not consider a power supply system that outputs AC power using a battery string. If a power supply system that outputs AC power using a battery string could be realized, the range of applications for the battery string would be expanded, and the cost of the battery string could be reduced.

[0005] An object of the present disclosure is to provide a power supply system that outputs AC power using a battery string. [Means for solving the problem]

[0006] The power supply system of the present disclosure includes an AC sweep unit that outputs AC power from a Y-connected U-phase battery string, a V-phase battery string, and a W-phase battery string, a first power supply circuit that converts the output of the DC sweep unit including the first battery string into AC power using an inverter and outputs the AC power, and a control device that controls the AC sweep unit and the first power supply circuit. Each of the U-phase battery string, the V-phase battery string, the W-phase battery string, and the first battery string includes a plurality of battery circuit modules connected in series. Each of the plurality of battery circuit modules includes a battery, an output terminal that outputs the battery voltage, a first switch connected to the output terminal and connected in parallel to the battery, and a second switch connected in series to the battery, and is configured such that the battery voltage is applied to the output terminal when the first switch is in an OFF state and the second switch is in an ON state. The first power supply circuit and the AC sweep unit are electrically connectable to an external power supply, and the energy density of the batteries included in the U-phase battery string, the V-phase battery string, and the W-phase battery string is higher than the energy density of the batteries included in the first battery string.

[0007] According to this configuration, the output voltage of the battery string can be controlled by controlling the states of the first and second switches of the battery circuit module. Since the U-phase battery string, the V-phase battery string, and the W-phase battery string of the AC sweep unit are Y-connected, AC power (e.g., three-phase AC power) can be output to an external power supply by controlling the output voltage of each battery string. By converting the DC power output from the first battery string into AC power using an inverter, the AC power can be output from the first power supply circuit to the external power supply.

[0008] Since the AC sweep unit outputs AC power by controlling the first and second switches of the battery circuit module, it is relatively inefficient and it is desirable to suppress the maximum output (maximum power), and it is preferable to use the batteries of the battery string of the AC sweep unit so that they are charged and discharged at a low rate. The energy density of the batteries included in the U-phase battery string, the V-phase battery string, and the W-phase battery string is higher than the energy density of the batteries included in the first battery string, so it becomes possible to output AC power efficiently and stably.

[0009] The power density of the batteries included in the first battery string is higher than the power density of the batteries included in the U-phase battery string, the V-phase battery string, and the W-phase battery string.

[0010] The first power supply circuit uses an inverter to output AC power, and is therefore more efficient than an AC sweep unit. The batteries included in the first battery string have a higher output density than the batteries included in the U-phase battery string, the V-phase battery string, and the W-phase battery string, and therefore it is possible to suitably output AC power from the first power supply circuit when high output is required. In addition, by combining a power type battery (high output type battery) with high output density with an energy type battery (high capacity battery) with high energy density, it is possible to make each battery perform the output (high output / long-term output) that it is good at. This makes it possible to provide a high-output, high-capacity power supply system at a lower cost than a power supply system using only energy type batteries or only power type batteries.

[0011] The batteries included in the first battery string are nickel-metal hydride batteries, and the batteries included in the U-phase battery string, the V-phase battery string, and the W-phase battery string are lithium-ion batteries.

[0012] In the currently popular electric vehicles, either nickel-metal hydride batteries or lithium-ion batteries are often used as batteries for storing power for driving. In general, in terms of battery characteristics, nickel-metal hydride batteries are high output and low capacity, while lithium-ion batteries are low output and high capacity. For this reason, it is possible to configure the power supply system of the present disclosure by reusing nickel-metal hydride batteries and lithium-ion batteries used in electric vehicles.

[0013] The control device may control the AC sweep unit and the first power supply circuit to adjust the power of the external power supply based on the input and output power of the AC sweep unit and the first power supply circuit, and when the power required by the power adjustment is within a predetermined range, connect the AC sweep unit to the external power supply and adjust the power of the external power supply by the AC sweep unit, and when the power required by the power adjustment exceeds the predetermined range, connect the first power supply circuit in addition to the AC sweep unit to the external power supply and adjust the power of the external power supply by the AC sweep unit and the first power supply circuit.

[0014] According to this configuration, when the power required by power adjustment is within a predetermined range, power adjustment of the external power source is performed by an AC sweep unit composed of a U-phase battery string, a V-phase battery string, and a W-phase battery string, each of which includes a high energy density battery, thereby enabling stable power adjustment.

[0015] Furthermore, when the power required by the power adjustment exceeds a predetermined range, the power adjustment of the external power supply is performed using the first power supply circuit in addition to the AC sweep unit, so that high-output power adjustment can be supported. In particular, when the output density of the batteries included in the first battery string is high, high-output AC power can be suitably output from the first power supply circuit.

[0016] The batteries included in the U-phase battery string, the V-phase battery string, and the W-phase battery string may be charged with power from an external power source, and the control device may control the AC sweep unit so that the storage capacity of the U-phase battery string, the V-phase battery string, and the W-phase battery string are the same.

[0017] According to this configuration, the batteries included in the U-phase battery string, the V-phase battery string, and the W-phase battery string are charged with power from an external power supply. At this time, the amount of charge stored in the U-phase battery string, the V-phase battery string, and the W-phase battery string are controlled to be the same, so that the amount of power (Wh) stored in each battery string is the same, and AC power can be stably output from the AC sweep unit.

[0018] The batteries included in the U-phase battery string, the V-phase battery string, and the W-phase battery string are charged with power from an external power source, and the control device may be configured to control the AC sweep unit so that when the batteries included in the U-phase battery string, the V-phase battery string, and the W-phase battery string are fully charged, the control device turns on a first switch of a battery circuit module including the fully charged battery and turns off a second switch of the battery circuit module including the fully charged battery, and disconnects the battery circuit module including the fully charged battery from the series connection.

[0019] With this configuration, the batteries included in the U-phase battery string, the V-phase battery string, and the W-phase battery string are charged with power from an external power source. During this, the first switch of the battery circuit module including the fully charged battery is turned ON and the second switch is turned OFF to disconnect the battery circuit module (battery) from the series connection, preventing the battery from being overcharged.

[0020] The control device may detect the degree of deterioration of the batteries included in the U-phase battery string, the V-phase battery string, and the W-phase battery string, and control the AC sweep unit to turn on a first switch and turn off a second switch of a battery circuit module including a battery whose degree of deterioration is greater than a predetermined value, thereby disconnecting the battery circuit module including a battery whose degree of deterioration is greater than a predetermined value from the series connection.

[0021] According to this configuration, the first switch of the battery circuit module including a battery whose degree of deterioration is greater than a predetermined value is turned ON and the second switch is turned OFF, thereby disconnecting the battery circuit module (battery) from the series connection, thereby enabling stable AC power to be output from the AC sweep unit. Effect of the Invention

[0022] According to the present disclosure, it is possible to provide a power supply system that outputs AC power using a battery string. [Brief description of the drawings]

[0023] [Figure 1] 1 is a diagram showing a configuration of a power supply system 1 according to the present embodiment. [Diagram 2] FIG. 2 is a diagram showing the configuration of a sweep unit SU. [Diagram 3] 4 is a time chart showing an example of the operation of the battery circuit module M controlled by a gate signal. [Figure 4] FIG. 2 is a diagram showing a battery circuit module M in a driven state. [Diagram 5] FIG. 11 is a diagram showing the state of the battery circuit module M during a delay period. [Figure 6] 11 is a diagram showing the state of the battery circuit module M during a stop period. FIG. [Figure 7] FIG. 2 is a diagram showing the configuration of a first inverter 50. [Figure 8] FIG. 2 is a diagram showing the configuration of an AC sweep unit 3. [Figure 9]10 is a flowchart showing an example of an output request process executed by the GCU 100 when a power output is requested by the server 200 due to power adjustment. [Figure 10] 10 is a flowchart showing an example of an adjustment request process executed by the GCU 100 when a power adjustment request is made by the server 200. [Figure 11] 4 is a flowchart showing an example of a power storage amount control process executed by the GCU 100. [Figure 12] 4 is a flowchart showing an example of an overcharge suppression control process executed by the GCU 100. [Figure 13] 4 is a flowchart showing an example of a degradation control process executed by the GCU 100. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and their description will not be repeated.

[0025] 1 is a diagram showing the configuration of a power supply system according to the present embodiment. The power supply system 1 includes a first power supply circuit 2, an AC sweep unit 3, and a GCU (Group Control Unit) 100.

[0026] The first power supply circuit 2 includes a first DC sweep unit 10, a second DC sweep unit 20, a third DC sweep unit 30, a first inverter 50, a second inverter 60, and a third inverter 70. In this embodiment, the configurations of SCU (String Control Unit) D1-D3, A1-A6, and battery strings St1-St9 are substantially the same among the first DC sweep unit 10, the second DC sweep unit 20, the third DC sweep unit 30, and the AC sweep unit 3, so these configurations will be described with reference to FIG. 2. In the following, when the battery strings St1-St9 are not distinguished from each other, the battery strings St1-St9 are referred to as "battery string St", and when the SCUD1-D3, A1-A6 are not distinguished from each other, the SCUD1-D3, A1-A6 are simply referred to as "SCU". In addition, the configuration including the SCU and the battery string St is referred to as "sweep unit SU".

[0027] 2 is a diagram showing the configuration of a sweep unit SU. The sweep unit SU includes an SCU, a drive circuit SUA, and a battery string St. The battery string St includes a plurality of battery circuit modules M. In this embodiment, the number of battery circuit modules M included in the battery string St is 22, but the number is arbitrary and may be 5 to 50, or may be 100 or more. In this embodiment, each battery string St includes the same number of battery circuit modules M, but the number of battery circuit modules M may differ for each battery string St.

[0028] Each battery circuit module M includes a power circuit SUB and a cartridge Cg. The cartridge Cg includes a battery B and a monitoring unit BS. The power circuit SUB and the battery B are connected to form a battery circuit module M including the battery B. The drive circuit SUA is configured to drive switches (more specifically, SW11 and SW12 described below) included in the battery circuit module M. The battery B may be a nickel-metal hydride secondary battery or a lithium-ion secondary battery. The battery B may be manufactured by connecting secondary batteries used in electric vehicles in series.

[0029] As shown in FIG. 2, the battery circuit module M includes a power circuit SUB, a cartridge Cg, and circuit breakers RB1 and RB2 (hereinafter, referred to as "circuit breakers RB" when no distinction is made). The power circuit SUB and the cartridge Cg are connected to each other via the circuit breakers RB1 and RB2. The SCU is configured to switch the connection state (conduction / disconnection) between the power circuit SUB and the cartridge Cg by controlling the circuit breakers RB to turn on / off in accordance with a control command from the GCU 100. The circuit breakers RB may be electromagnetic mechanical relays. The circuit breakers RB may be configured to be manually turned on / off by a user.

[0030] In this embodiment, the cartridge Cg is configured to be detachable from the power circuit SUB. For example, when each of the circuit breakers RB1 and RB2 is in the OFF state (disconnected state), the user may remove the cartridge Cg from the power circuit SUB. Since the battery string St can operate even if there is an empty cartridge, the user can easily increase or decrease the number of cartridges Cg included in the battery string St. Such a battery string St is suitable for reusing batteries.

[0031] In the cartridge Cg, the monitoring unit BS is configured to detect the state (e.g., voltage, current, and temperature) of the battery B and output the detection result to the SCU. The monitoring unit BS includes a voltage sensor that detects the voltage of the battery B, a current sensor that detects the current of the battery B, and a temperature sensor that detects the temperature of the battery B. The monitoring unit BS may be a BMS (Battery Management System) that further has a SOC (State Of Charge) estimation function, a SOH (State of Health) estimation function, a battery voltage equalization function, a diagnosis function, and a communication function in addition to the above sensor function. The SCU acquires the state (e.g., temperature, current, voltage, SOC, and internal resistance) of each battery B based on the output of each monitoring unit BS, and outputs the acquired state of each battery B to the GCU 100.

[0032] The battery circuit modules M included in the battery string St are connected by a common electric wire PL. The electric wire PL includes output terminals OT1 and OT2 of each battery circuit module M. The output terminal OT2 of a battery circuit is connected to the output terminal OT1 of a battery circuit adjacent to the battery circuit module M, thereby connecting the battery circuit modules M included in the battery string St to each other.

[0033] The power circuit SUB includes a first switching element 11 (hereinafter referred to as "SW11"), a second switching element 12 (hereinafter referred to as "SW12"), a first diode 13, a second diode 14, a choke coil 15, a capacitor 16, and output terminals OT1 and OT2. Each of SW11 and SW12 is driven by a drive circuit SUA. SW11 and SW12 according to this embodiment correspond to examples of the "first switch" and "second switch" according to the present disclosure, respectively.

[0034] Between the output terminals OT1 and OT2 of the power circuit SUB, SW11, a capacitor 16, and a battery B are connected in parallel. SW11 is located on the electric wire PL, and is configured to switch the connection state (conduction / cut-off) between the output terminals OT1 and OT2. The output terminal OT1 is connected to the positive electrode of the battery B via the electric wire BL1, and the output terminal OT2 is connected to the negative electrode of the battery B via the electric wire BL2. Circuit breakers RB1 and RB2 are provided on the electric wires BL1 and BL2, respectively. SW12 and a choke coil 15 are further provided on the electric wire BL1. In the battery circuit BC, when SW12 connected in series to the battery B is in the ON state (connection state) and SW11 connected in parallel to the battery B is in the OFF state (cut-off state), the voltage of the battery B is applied between the output terminals OT1 and OT2.

[0035] A capacitor 16 connected to each of the electric wires BL1 and BL2 is provided between the output terminals OT1, OT2 and the battery B. One end of the capacitor 16 is connected to the electric wire BL1 between SW12 and the choke coil 15. The capacitor 16 smoothes the voltage of the battery B and outputs it between the output terminals OT1 and OT2.

[0036] Each of SW11 and SW12 is, for example, a field effect transistor (FET). The first diode 13 and the second diode 14 are connected in parallel to SW11 and SW12, respectively. SW12 is located between the output terminal OT1 and the choke coil 15. The choke coil 15 is located between SW12 and the positive electrode of the battery B. The battery B, the choke coil 15, and the capacitor 16 form an RCL filter. This RCL filter smooths the current. Each of SW11 and SW12 is not limited to a FET, and may be a switch other than a FET.

[0037] The SCU generates a gate signal according to a control command from the GCU 100. The drive circuit SUA is provided for each battery circuit module M, and includes a GD (gate driver) 81 that drives SW11 and SW12 according to the gate signal, and a delay circuit 82 that delays the gate signal. Each of SW11 and SW12 included in the battery circuit module M is ON / OFF controlled according to the gate signal.

[0038] FIG. 3 is a time chart showing an example of the operation of the battery circuit module M controlled by a gate signal. In this embodiment, a square wave signal is adopted as the gate signal for driving SW11 and SW12. "Low" and "High" of the gate signal shown in FIG. 3 respectively mean the L level and H level of the gate signal (square wave signal). Also, "output voltage" means the voltage output between the output terminals OT1 and OT2.

[0039] In the initial state of the battery circuit module M, no gate signal is input to the drive circuit SUA (gate signal=L level), and SW11 and SW12 are in the ON and OFF states, respectively.

[0040] When a gate signal is input to the drive circuit SUA, GD81 drives SW11 and SW12 in accordance with the input gate signal. In the example shown in FIG. 3, the gate signal rises from L level to H level at timing t1, and SW11 switches from ON state to OFF state at the same time as the gate signal rises. Then, at timing t2, which is delayed by a predetermined time (hereinafter referred to as "dt1") from the rise of the gate signal, SW12 switches from OFF state to ON state. This causes the battery circuit module M to enter a drive state. Hereinafter, the period from the rise of the gate signal to the elapse of dt1 is also referred to as the "first delay period."

[0041] 4 is a diagram showing the battery circuit module M in a driven state. In the battery circuit BC in a driven state, SW11 is turned OFF and SW12 is turned ON, so that the voltage of battery B is applied between output terminals OT1 and OT2. The voltage of battery B is applied between output terminals OT1 and OT2 via capacitor 16, so that voltage Vm is output between output terminals OT1 and OT2.

[0042] Referring to FIG. 3, when the gate signal falls from H level to L level at timing t3, SW12 switches from ON state to OFF state at the same time as the gate signal falls. This causes the battery circuit module M to enter a stopped state. In the stopped battery circuit module M, SW12 goes to OFF state, and the voltage of the battery B is no longer applied between the output terminals OT1 and OT2. Thereafter, at timing t4, which is delayed by a predetermined time (hereinafter, referred to as "dt2") from the falling edge of the gate signal, SW11 switches from OFF state to ON state. dt1 and dt2 may be the same or different from each other. In this embodiment, each of dt1 and dt2 is set to 100 nsec. However, each of dt1 and dt2 can be set arbitrarily.

[0043] Hereinafter, the period from the falling edge of the gate signal until dt2 has elapsed is also referred to as the “second delay period.” Also, the period from the end of the second delay period until the battery circuit module M is in a driving state is also referred to as the “stop period.”

[0044] Fig. 5 is a diagram showing the state of the battery circuit module M during the delay period. As shown in Fig. 5, during each of the first delay period and the second delay period, both SW11 and SW12 are in the OFF state.

[0045] Fig. 6 is a diagram showing the state of the battery circuit module M during a suspension period. As shown in Fig. 6, during a suspension period, like the initial state, SW11 is in the ON state and SW12 is in the OFF state.

[0046] During both the delay period and the stop period, the battery circuit module M is in a stopped state. In the stopped battery circuit module M, no voltage is applied between the output terminals OT1 and OT2. By providing the first delay period and the second delay period, it is possible to prevent SW11 and SW12 from being in the ON state at the same time (i.e., the battery circuit module M from being in a short-circuit state).

[0047] By controlling the battery circuit modules M included in the battery string St as described above, it is possible to adjust the number of battery circuit modules M in an operating state, and to control the output voltage of the battery string St. This (by adjusting the number of battery circuit modules M that are simultaneously in an operating state) configures the sweep unit SU to be able to output a voltage ranging from 0 V to the sum of the voltages of the batteries B included in the battery string St.

[0048] Referring to FIG. 1, the first DC sweep unit 10 is a sweep unit SU configured as described above, and includes a battery string St1 and a battery string SUDD1. The battery B of the battery circuit module M included in the battery string St1 is a nickel-metal hydride secondary battery. The DC power output from the first DC sweep unit 10 is input to a first inverter 50. FIG. 7 is a diagram showing a configuration of the first inverter 50. The first inverter 50 is a three-phase inverter, and includes switching elements q1 and q2 connected in series to a U-phase arm, switching elements q3 and q4 connected in series to a V-phase arm, and switching elements q5 and q6 connected in series to a W-phase arm. Diodes d1 to d6 are connected in antiparallel between the collectors and emitters of the switching elements q1 to q6, respectively.

[0049] The midpoint of each phase arm of the first inverter 50 is connected to an insulating filter T1, and is further connected to a power grid PG via a relay R1 and a distribution board C1 (see FIG. 1). Each switching element q1-q6 of the first inverter 50 is turned ON / OFF by, for example, PWM (Pulse Width Modulation) control in response to a control command from the GCU 100. The first inverter 50 converts the DC power output from the first DC sweep unit 10 into AC power (three-phase AC power) and supplies it to the power grid PG. The first inverter 50 also converts the AC power (three-phase AC power) supplied from the power grid PG into DC power and supplies it to the first DC sweep unit 10 to charge the battery B of the battery string St1. In this embodiment, the first inverter 50 reuses a three-phase inverter used to drive a three-phase synchronous motor of an electric vehicle.

[0050] 1, the second DC sweep unit 20 including the battery strings St2 and SCUD2, and the third DC sweep unit 30 including the battery strings St3 and SCUD3 have the same configuration as the first DC sweep unit 10. The second inverter 60 connected to the second DC sweep unit 20, and the third inverter 70 connected to the third DC sweep unit 30 have the same configuration as the first inverter 50. The midpoints of the phase arms of the first inverter 50, the second inverter 60, and the third inverter 70 are connected by a power line, and the first DC sweep unit 10, the second DC sweep unit 20, and the third DC sweep unit 30 are (electrically) connected in parallel with the insulating filter T1. As a result, the first power supply circuit 2 outputs AC power (three-phase AC power) from the first DC sweep unit 10, the second DC sweep unit 20, and the third DC sweep unit 30, which are connected in parallel (using the first to third inverters 50 to 70).

[0051] Fig. 8 is a diagram showing the configuration of the AC sweep unit 3. The first U-phase battery string St4 and SCUA1 have substantially the same configuration as the sweep unit SU described in Fig. 2. The "second U-phase battery string St5 and SCUA2," "first V-phase battery string St6 and SCUA3," "second V-phase battery string St7 and SCUA4," "first W-phase battery string St8 and SCUA5," and "second W-phase battery string St9 and SCUA6" are also similar.

[0052] In this embodiment, the batteries B of the battery circuit modules M included in the first U-phase battery string St4, the first V-phase battery string St6, and the first W-phase battery string St8 are ternary (NMC) lithium-ion secondary batteries. Also, the batteries B of the battery circuit modules M included in the second U-phase battery string St5, the second V-phase battery string St7, and the second W-phase battery string St9 are iron phosphate (LFP) lithium-ion secondary batteries.

[0053] In FIG. 8, the positive terminal of the first U-phase battery string St4 and the positive terminal of the second U-phase battery string St5 are connected to the power line PLu via relays r4 and r5, respectively. The positive terminal of the first V-phase battery string St6 and the positive terminal of the second V-phase battery string St7 are connected to the power line PLv via relays r6 and r7, respectively. The positive terminal of the first W-phase battery string St8 and the positive terminal of the second W-phase battery string St9 are connected to the power line PLw via relays r8 and r9, respectively. In addition, the negative terminals of the battery strings St4 to St9 are connected to the neutral point N1. As a result, the AC sweep unit 3 has a Y-connected configuration of "a first U-phase battery string St4 and a second U-phase battery string St5 connected in parallel," "a first V-phase battery string St6 and a second V-phase battery string St7 connected in parallel," and "a first W-phase battery string St8 and a second W-phase battery string St9 connected in parallel."

[0054] The relays r4 to r9 may be electromagnetic mechanical relays. The relays r4 to r9 are ON / OFF controlled by the GCU 100 or the SCUAs 1 to 6 to connect / disconnect the battery strings St4 to St9 and the power lines PLu to Plw. When the SCUAs 1 to 6 and the battery strings St4 to St9 are normal, the relays r4 to r9 are always in the ON state and connect the battery strings St4 to St9 and the power lines PLu to Plw. When an abnormality (fault) occurs in any of the SCUAs 1 to 6 or the battery strings St4 to St9, the relays r4 to r9 corresponding to the SCUAs 1 to 6 or the battery strings St4 to St9 where the abnormality occurs are switched to the OFF state, and the battery string St is disconnected from the power line.

[0055] The AC sweep unit 3 is provided with a voltage sensor Vu, a voltage sensor Vv, and a voltage sensor Vw. The voltage sensor Vu detects a U-phase string voltage, which is the voltage of the first U-phase battery string St4 and the second U-phase battery string St5. The voltage sensor Vv detects a V-phase string voltage, which is the voltage of the first V-phase battery string St6 and the second V-phase battery string St7. The voltage sensor Vw detects a W-phase string voltage, which is the voltage of the first W-phase battery string St8 and the second W-phase battery string St9.

[0056] The AC sweep unit 3 includes current sensors Ia to If. The current sensor Ia detects the input / output current of the first U-phase battery string St4. The current sensor Ib detects the input / output current of the second U-phase battery string St5. The current sensor Ic detects the input / output current of the first V-phase battery string St6. The current sensor Id detects the input / output current of the second U-phase battery string St7. The current sensor Ie detects the input / output current of the first W-phase battery string St8. The current sensor If detects the input / output current of the second W-phase battery string St9.

[0057] In response to a control command from the GCU 100, the SCUA1 to A6 control the SW11 and SW12 of each battery circuit module M at a switching frequency of several tens of kHz to control the string voltage (output voltage) of each battery string St4 to St9 to have a voltage waveform shown in the lower part of FIG. 8. In FIG. 8, line L11 is the string voltage of the first U-phase battery string St4 and the second U-phase battery string St5. Line L12 is the string voltage of the first V-phase battery string St6 and the second V-phase battery string St7. Line L13 is the string voltage of the first W-phase battery string St8 and the second W-phase battery string St9. Lines L11, L12, and L13 are sine waves with a phase difference of 120°, and the frequency is 60 Hz corresponding to the power system PG.

[0058] In this way, by controlling the string voltages of the battery strings St4 to St9, the line voltages of the power lines PLu, PLv, and PLw become the voltage waveforms shown in the upper part of Fig. 8. In Fig. 8, line L21 indicates the line voltage "Vuv" between the power lines PLu and PLv, line L22 indicates the line voltage "Vwu" between the power lines PLw and PLu, and line L23 indicates the line voltage "Vvw" between the power lines PLv and PLw. Each line voltage becomes a sinusoidal AC waveform whose polarity (positive / negative) changes periodically. As a result, AC power (three-phase AC power) is output from the AC sweep unit 3.

[0059] 1, AC power output from the first power supply circuit 2 is supplied to the power system PG via an insulating filter T1, a relay R1, and a distribution board C1. AC power output from the AC sweep unit 3 is supplied to the power system PG via an insulating filter T2, a relay R2, and a distribution board C1.

[0060] The insulating filter T1 and the insulating filter T2 each include, for example, an LCL filter and a three-phase transformer. The insulating filter T1 and the insulating filter T2 reduce noise components of the three-phase AC components using the LCL filter, and convert the three-phase AC power to a predetermined voltage (for example, 200 V) using the three-phase transformer while providing insulation between the input side and the output side.

[0061] The relays R1 and R2 may be electromagnetic mechanical relays, and the first power supply circuit 2 and the power system PG are connected (in parallel) / disconnected (disconnected) by controlling the ON / OFF of the relay R1 by the GCU 100. Also, the AC sweep unit 3 and the power system PG are connected / disconnected by controlling the ON / OFF of the relay R2 by the GCU 100.

[0062] The distribution board C1 includes a leakage current breaker and / or a circuit breaker, and distributes power from the power system PG to the first power supply circuit 2 and the AC sweep unit 3 when charging the batteries B of the battery string St included in the first power supply circuit 2 and the AC sweep unit 3. The distribution board C1 also supplies power output from the first power supply circuit 2 and the AC sweep unit 3 to the power system PG.

[0063] When charging the battery B of the battery string St included in the first power supply circuit 2, the first to third inverters 50-70 convert the AC power supplied from the power system PG into DC power to charge the battery B. When charging the battery B of the battery string St included in the AC sweep unit 3, SCUA1-A6 charge the battery B by controlling SW11 and SW12 so that the voltage of the battery string St is slightly lower than the AC voltage supplied from the power system PG.

[0064] The AC power of the first power supply circuit 2 and the AC power of the AC sweep unit 3 supplied to the power system PG are supplied to wiring within the premises or house via the distribution board C2 together with the AC power of the power system PG.

[0065] The server 200 manages the supply and demand of a power system PG (power grid) provided by a power company (a power generation business operator and a power transmission and distribution business operator). The server 200 is configured to be able to communicate with the GCU 100, and requests the GCU 100 to adjust the power of the power system PG as necessary. Upon receiving the request from the server 200, the GCU 100 controls the SUC of the sweep unit SU, the first to third inverters 50 to 70, and the relays R1 and R2, and adjusts the input and output power of the first power supply circuit 2 and the AC sweep unit 3.

[0066] <Output request processing> 9 is a flowchart showing an example of an output request process executed by the GCU 100 when the server 200 requests the output of power due to power adjustment. This flowchart is executed when the GCU 100 receives an output request from the server 200. Upon receiving an output request from the server 200, the GCU 100 determines in step (hereinafter, step is abbreviated as "S") 10 whether the requested power is equal to or less than α. α is a value that is set in advance depending on specifications such as the number of battery strings St that the power supply system 1 has, and may be, for example, 20 kW. If the requested output is equal to or less than α, a positive determination is made in S10 and the process proceeds to S11.

[0067] In S11, the GCU 100 outputs AC power from the AC sweep unit 3 and supplies it to the power grid PG. The GCU 100 also turns on relay R2 to connect (in parallel) the AC sweep unit 3 and the power grid PG, and controls SW11 and SW12 of the battery strings St4 to St9 via SCUA1 to A6 to output AC power (three-phase AC power) from the AC sweep unit 3.

[0068] If the required power is greater than α, a negative determination is made in S10 and the process proceeds to S12. In S12, the GCU 100 causes the first power supply circuit 2 to output AC power in addition to the AC sweep unit 3, and supplies the AC power to the power system PG. In addition to outputting AC power (three-phase AC power) from the AC sweep unit 3 as described above, the GCU 100 turns on the relay R1 to connect (in parallel) the first power supply circuit 2 and the power system PG. The GCU 100 controls SW11 and SW12 of the battery strings St1 to St3 using SCUD1 to D3, thereby causing the first DC sweep unit 10, the second DC sweep unit 20, and the third DC sweep unit 30 to output DC power. The GCU 100 converts the DC power into AC power using the first to third inverters 50 to 70, and supplies the AC power (three-phase AC power) to the power system PG. In this way, when the required power is larger than α, the GCU 100 causes the first power supply circuit 2 and the AC sweep unit 3 to output AC power and supply it to the power grid PG.

[0069] The battery B of the battery string St of the first DC sweep unit 10, the second DC sweep unit 20, and the third DC sweep unit 30 included in the first power supply circuit 2 is a nickel-metal hydride secondary battery. The battery B of the battery string St of the AC sweep unit 3 is a lithium-ion secondary battery. Due to the characteristics of the battery, the output density (W / kg) of the nickel-metal hydride secondary battery is greater than that of the lithium-ion secondary battery. Also, the energy density (Wh / kg) of the lithium-ion secondary battery is greater than that of the nickel-metal hydride secondary battery. For this reason, the nickel-metal hydride secondary battery is located in the upper left region of the Ragone plot, and can be said to be a power type (output type) battery. Also, the lithium-ion secondary battery is located in the lower right region of the Ragone plot, and can be said to be an energy type (capacity type) battery.

[0070] In the AC sweep unit 3, the SW11 and SW12 of the battery string St are controlled at several tens of kHz to output AC power. Therefore, it is desirable to suppress the maximum output (maximum power) because of poor efficiency (low efficiency). Therefore, in order to increase the output (power (W)) of the AC sweep unit 3, it is necessary to increase the number of parallel battery strings St, which leads to an increase in costs. For this reason, it is preferable to use the battery B of the battery string St of the AC sweep unit 3 so that it is charged and discharged at a low rate. Therefore, it is desirable for the battery B of the battery string St of the AC sweep unit 3 to be an energy type battery with a high energy density, and therefore a lithium ion secondary battery is used in this embodiment.

[0071] In contrast, the first power supply circuit 2 uses an inverter to output AC power, which is relatively efficient and allows for a large maximum output. Therefore, by using a power type battery with a high output density as the battery B of the battery string St of the first power supply circuit 2 (the battery B of the battery string St of the first DC sweep unit 10, the second DC sweep unit 20, and the third DC sweep unit 30), a large output (power (W)) can be output from the first power supply circuit 2, so in this embodiment, a nickel-metal hydride secondary battery is used.

[0072] According to the output request process in Fig. 9, when the requested power is equal to or less than α, AC power is output from the AC sweep unit 3. In this case, since the energy density of the AC sweep unit 3 (energy density of the battery B of the battery string St of the AC sweep unit 3) is large and the capacity is large, stable AC power can be output for a long period of time. When the requested power is greater than α and the power output from the power supply system 1 is large, AC power can be output from the first power supply circuit 2 in addition to the AC sweep unit 3, thereby making it possible to output AC power that satisfies the requested power.

[0073] <Adjustment request processing> FIG. 10 is a flowchart showing an example of an adjustment request process executed by the GCU 100 when a power adjustment request is made from the server 200. This flowchart is executed when the GCU 100 receives an adjustment request from the server 200. The adjustment capability requested by the server 200 is an amount of power that can be adjusted by output adjustment of a generator output or the like to suppress frequency fluctuations and supply-demand imbalance, and is roughly divided into frequency adjustment capability and supply-demand adjustment capability. The frequency adjustment capability is governor-free or load frequency control (LFC) that adjusts output according to frequency fluctuations on the order of seconds to minutes, and the supply-demand adjustment capability is economic load dispatching control (EDC) that resolves power supply-demand imbalances on a long cycle of minutes or more. The frequency adjustment capability has a fast output change (response time) until a command value is reached, and the output duration is relatively short. The supply-demand adjustment capability has a slow response time and a relatively long output duration.

[0074] 10, in S20, the GCU 100 judges whether the adjustment request is a demand adjustment capacity. If the adjustment request is a demand adjustment capacity and the judgment is affirmative, the process proceeds to S21. If the demand adjustment capacity is not requested, the adjustment request is a frequency adjustment capacity and the judgment is negative, the process proceeds to S22.

[0075] In S21, the GCU 100 operates the AC sweep unit 3. That is, the GCU 100 turns on the relay R2 to connect (in parallel) the AC sweep unit 3 and the power grid PG. When the adjustment request is a downward DR (demand response), the SCUA1 to A6 control SW11 and SW12 of the battery strings St4 to St9 to output AC power (three-phase AC power) from the AC sweep unit 3, and reverse power flow is performed. When the adjustment request is an upward DR, the GCU 100 controls SW11 and SW12 by the SCUA1 to A6 so that the voltage of the battery string St is slightly lower than the AC voltage supplied from the power grid PG, and appropriately charges the battery B of the battery string St included in the AC sweep unit 3.

[0076] In S22, the GCU100 operates the AC sweep unit 3 and the first power supply circuit 2. That is, in addition to operating the AC sweep unit 3, the GCU100 turns on the relay R1 to connect (in parallel) the first power supply circuit 2 and the power grid PG. When the adjustment request is a down DR (demand response), the GCU100 controls SW11 and SW12 of the battery strings St1 to St3 by SCUD1 to D3 to output DC power from the first DC sweep unit 10, the second DC sweep unit 20, and the third DC sweep unit 30. The GCU100 converts the DC power into AC power using the first to third inverters 50 to 70, and supplies the AC power (three-phase AC power) to the power grid PG. When the adjustment request is an up DR, the GCU100 converts the AC power of the power grid PG into DC power using the first to third inverters 50 to 70. The GCU 100 appropriately charges the batteries B included in the first DC sweep unit 10, the second DC sweep unit 20 and the third DC sweep unit 30 by controlling SW11 and SW12 of the battery strings St1 to St3 using SCUD1 to D3.

[0077] The adjustment reserves handled in the supply and demand adjustment market are divided into primary adjustment reserve, secondary adjustment reserve (1), secondary adjustment reserve (2), tertiary adjustment reserve (1) and tertiary adjustment reserve (2), in order of the fastest output change (response time) to the command value and the shortest output duration. In the governor-free system, which corresponds to the primary adjustment reserve, the output is increased or decreased in response to changes in the system frequency, and in the LFC system, which corresponds to the secondary adjustment reserve (1), the frequency fluctuation caused by the load fluctuation is adjusted. In the EDC system, which corresponds to the secondary adjustment reserve (2) and tertiary adjustment reserve (1), the output is allocated to the generators so as to be the most economical. In addition, the tertiary adjustment reserve (2) is positioned as the adjustment reserve for the low-speed frame. Therefore, when the requested adjustment reserve is the primary adjustment reserve or the secondary adjustment reserve (1), the adjustment request is treated as a frequency adjustment reserve, and in the case of other adjustment reserves, the adjustment request is treated as a supply and demand adjustment reserve.

[0078] A power supply system with a relatively large capacity is required for demand adjustment capability, which has a relatively long adjustment time and a long-cycle load fluctuation. A power supply system with high response is required for frequency adjustment capability, which requires a fast response time and high responsiveness. According to the adjustment request process in FIG. 10, for demand adjustment capability, which has a long adjustment time and requires a large capacity, the adjustment request can be stably met by operating the AC sweep unit 3, which has a large energy density (energy density of battery B of the battery string St of the AC sweep unit 3) and a large capacity. For frequency adjustment capability, which has a short-cycle load fluctuation and requires a fast response time and high responsiveness, the adjustment request can be met by operating the first power supply circuit 2, which includes battery B (nickel-metal hydride secondary battery) with a high output density, in addition to the AC sweep unit 3.

[0079] The output request process in Fig. 9 and the adjustment request process in Fig. 10 are executed by the GCU 100 (control device) when a request is received from the server 200 to perform power adjustment of the power system PG (external power source). In the output request process, when the power requested by the power adjustment is equal to or less than a predetermined value α, AC power is output from the AC sweep unit 3, and when the requested power exceeds the predetermined value α, AC power is output from the AC sweep unit 3 and the first power supply circuit 2. In the adjustment request process, when the power requested by the power adjustment is demand adjustment capability, power adjustment is performed by the AC sweep unit 3, and when the requested power is frequency adjustment capability, power adjustment is performed by the AC sweep unit 3 and the first power supply circuit 2.

[0080] In the case of demand adjustment capability, the fluctuations in the input / output power required of the power supply system 1 are long-period, and the charging and discharging of battery B of the battery string St is performed at a low rate. In the case of frequency adjustment capability, the fluctuations in the required input / output power are short-period, and high responsiveness is required, and the charging and discharging of battery B of the battery string St is performed at a high rate. In this disclosure, "the power required by power adjustment is within a specified range" includes a case where the fluctuation period of the input / output power required by power adjustment is long, and the charging and discharging of battery B of the battery string St is performed at a low rate. Also, in this disclosure, "the power required by power adjustment exceeds a specified range" includes a case where the fluctuation period of the input / output power required by power adjustment is short, and the charging and discharging of battery B of the battery string St is performed at a high rate.

[0081] <Battery storage control> 11 is a flowchart showing an example of the processing of the storage amount control executed by the GCU 100. This flowchart is executed when charging of the battery B of the battery string St included in the AC sweep unit 3 is started. For example, when the adjustment request from the server 200 is an upward DR, the GCU 100 controls SW11 and SW12 by SCUA1 to A6 so that the voltage of the battery string St becomes slightly lower than the AC voltage supplied from the power system PG, starts charging of the battery B of the battery string St included in the AC sweep unit 3, and executes S30.

[0082] In S30, the GCU 100 calculates the amount of stored power (Wh) of each battery string St in the AC sweep unit 3. For example, the GCU 100 calculates the input power (W) to each battery string St from the voltage of each battery string St detected by the voltage sensors Vu, Vv, VW and the input current to each battery string St detected by the current sensors Ia to If, and calculates the amount of stored power of each battery string St (the amount of power (Wh) stored in each battery string St) by integrating the input power over the (charging) time.

[0083] In the next S31, the GCU 100 judges whether the difference between the amounts of stored electricity of each battery string St calculated in S30 is equal to or greater than a predetermined value. For example, if the difference between the maximum and minimum amounts of stored electricity is equal to or greater than a predetermined value β, the GCU 100 judges that the difference between the amounts of stored electricity of each battery string St is equal to or greater than the predetermined value. The predetermined value β may be, for example, 500 Wh. If the difference between the amounts of stored electricity of each battery string St is equal to or greater than the predetermined value and a positive judgment is made, the process proceeds to S32. If the difference between the maximum and minimum amounts of stored electricity is less than the predetermined value β and a negative judgment is made, the process proceeds to S33.

[0084] In S32, the GCU 100 controls the voltage of each battery string St to eliminate the difference in the amount of stored power among the battery strings St. For example, the GCU 100 controls the voltage of each battery string St to reduce the input power of a battery string St with a relatively large amount of stored power and to increase the input power of a battery string St with a relatively small amount of stored power, and then proceeds to S33.

[0085] In S33, the GCU 100 judges whether charging has been completed. The GCU 100 may judge that charging has been completed, for example, when the time for adjusting the upward DR requested by the server 200 has been completed. If charging has not been completed, a negative judgment is made, and the process returns to S30, and the processes from S30 onward are executed again. If charging has been completed, an affirmative judgment is made, and the current routine is terminated.

[0086] According to this power storage control, when the battery B included in the AC sweep unit 3 is charged with power from the power system PG (external power source), the first U-phase battery string St4, the second U-phase battery string St5, the first V-phase battery string St6, the second V-phase battery string St7, the first W-phase battery string St8, and the second W-phase battery string St9 are controlled to have the same amount of power stored. Therefore, the amount of power (Wh) stored in each battery string St becomes the same, and the AC sweep unit 3 can stably output AC power.

[0087] In S31, the GCU 100 may determine whether or not a difference between the "total amount of stored power of the first U-phase battery string St4 and the second U-phase battery string St5," the "total amount of stored power of the first V-phase battery string St6 and the second V-phase battery string St7," and the "total amount of stored power of the first W-phase battery string St8 and the second W-phase battery string St9" is equal to or greater than a predetermined value. In this case, in S32, the voltage of each battery string St is controlled to eliminate the difference between the "total amount of stored power of the first U-phase battery string St4 and the second U-phase battery string St5," the "total amount of stored power of the first V-phase battery string St6 and the second V-phase battery string St7," and the "total amount of stored power of the first W-phase battery string St8 and the second W-phase battery string St9." Even with this type of storage capacity control, the "total storage capacity of the first U-phase battery string St4 and the second U-phase battery string St5," the "total storage capacity of the first V-phase battery string St6 and the second V-phase battery string St7," and the "total storage capacity of the first W-phase battery string St8 and the second W-phase battery string St9" become the same, and AC power can be output stably from the AC sweep unit 3.

[0088] <Overcharge prevention control> 12 is a flowchart showing an example of the overcharge suppression control process executed by the GCU 100. This flowchart is executed when charging of the battery B of the battery string St included in the AC sweep unit 3 is started. For example, similar to the power storage amount control, charging is started when the adjustment request from the server 200 is an upward DR. When charging is started, the GCU 100 acquires the SOC of each battery B from the monitoring unit BS of the battery circuit module M of the battery string St included in the AC sweep unit 3 in S40, and then proceeds to S41.

[0089] In S41, the GCU 100 judges whether or not any battery B is fully charged based on the SOC of each battery B acquired in S40. The GCU 100 may, for example, judge a battery B with an SOC of 90% or more to be fully charged. If any battery B is fully charged, a positive judgment is made and the process proceeds to S42. If no battery B is fully charged, a negative judgment is made and the process proceeds to S43.

[0090] In S42, the GCU 100 turns on SW11 and turns off SW12 of the battery circuit module M including the fully charged battery B, and then proceeds to S43, whereby the battery circuit module M is brought into a stopped state (see FIG. 6).

[0091] In S43, the GCU 100 judges whether charging has been completed. The GCU 100 may judge that charging has been completed when the time for adjusting the upward DR requested by the server 200 has been completed. If charging has not been completed, a negative judgment is made and the process returns to S40, and the processes from S40 onward are executed again. If charging has been completed, an affirmative judgment is made and the current routine is terminated.

[0092] According to this overcharge suppression control, when the battery B included in the AC sweep unit 3 is charged with power from the power system PG (external power source), if the battery B included in the battery string St becomes fully charged, SW11 of the battery circuit module M including the fully charged battery B becomes ON and SW12 becomes OFF. Therefore, the battery B (battery circuit module M) is disconnected from the series connection. As a result, the fully charged battery B is not charged, and overcharge can be suppressed.

[0093] <Deterioration control> 13 is a flowchart showing an example of degradation control processing executed by the GCU 100. This flowchart is repeatedly processed at predetermined intervals during operation of the AC sweep unit 3. First, in S50, the GCU 100 acquires the SOH of each battery B from the monitoring unit BS of the battery circuit module M of the battery string St included in the AC sweep unit 3, and then proceeds to S51.

[0094] In S51, the GCU 100 judges whether or not there is a battery B whose degree of deterioration is equal to or greater than a predetermined value, based on the SOH of each battery B acquired in S50. In this embodiment, the monitoring unit BS estimates the capacity maintenance rate of the battery B as the SOH, and the GCU 100 judges a battery B whose SOH (capacity maintenance rate) is equal to or less than a predetermined value γ to be a battery B whose degree of deterioration is equal to or greater than the predetermined value. The predetermined value γ may be, for example, 50%. If there is a battery B whose degree of deterioration is equal to or greater than the predetermined value, a positive judgment is made and the process proceeds to S52. If there is no battery B whose degree of deterioration is equal to or greater than the predetermined value, a negative judgment is made and the current routine is terminated.

[0095] In S52, the GCU 100 turns on SW11 and turns off SW12 of the battery circuit module M including the battery B whose degree of deterioration is equal to or greater than a predetermined value, and then ends the current routine.

[0096] According to this degradation control, the degree of degradation of a battery B included in the battery string St of the AC sweep unit 3 is detected, and SW11 of the battery circuit module M including a battery B whose degree of degradation is equal to or greater than a predetermined value is turned ON and SW12 is turned OFF. Therefore, the battery B (battery circuit module M) is disconnected from the series connection. This allows the AC sweep unit 3 to operate without using a battery B with a large degree of degradation, thereby enabling stable output of AC power.

[0097] In addition, in the case where the monitoring unit BS estimates the rate of increase in the internal resistance of battery B as the SOH, the GCU 100 may determine that battery B whose rate of increase in internal resistance is equal to or greater than a set value is battery B whose degree of deterioration is equal to or greater than a predetermined value.

[0098] According to this embodiment, nickel-hydrogen secondary batteries with high output density are used as the batteries of the battery string St of the first power supply circuit 2, which converts the outputs of the first to third DC sweep units 10 to 30 into AC power using the first to third inverters 50 to 70 and outputs the AC power. Also, lithium-ion secondary batteries with high energy density are used as the batteries B of the AC sweep unit 3, which outputs AC power from the first and second U-phase battery strings St4 and St5, the first and second V-phase battery strings St6 and St7, and the first and second W-phase battery strings St8 and St9, which are Y-connected. Therefore, in the power supply system 1 of this embodiment, by combining a power type battery (nickel-hydrogen secondary battery) and an energy type battery (lithium ion secondary battery), it is possible to make each battery perform the output (high output / long-term output) that it is good at. As a result, it is possible to provide a power supply system 1 with high output and high capacity at a lower cost than a power supply system using only an energy type battery or only a power type battery.

[0099] In this embodiment, the AC sweep unit 3 outputs AC (three-phase AC) by Y-connecting the battery strings St. Since no inverter is used, costs can be reduced.

[0100] In this embodiment, in the first power supply circuit 2, a first DC sweep unit 10, a second DC sweep unit 20, and a third DC sweep unit 30 are connected in parallel. The first to third DC sweep units 10 to 30 correspond to the "DC sweep units" in the present disclosure, and the battery strings St1 to St3 correspond to the "first battery string" in the present disclosure. In this embodiment, three DC sweep units are connected in parallel, but the number of DC sweep units may be one, or four or more.

[0101] In this embodiment, first and second U-phase battery strings St4, St5 are used as U-phase battery strings, first and second V-phase battery strings St6, St7 are used as V-phase battery strings, and first and second W-phase battery strings St8, St59 are used as W-phase battery strings in the AC sweep unit 3. The number of U-phase battery strings, V-phase battery strings, and W-phase battery strings may be one, or may be three or more.

[0102] In this embodiment, ternary (NMC) lithium-ion secondary batteries are used for the batteries B of the first U-phase battery string St4, the first V-phase battery string St6, and the first W-phase battery string St8, and iron phosphate (LFP) lithium-ion secondary batteries are used for the batteries B of the second U-phase battery string St5, the second V-phase battery string St7, and the second W-phase battery string St9, but the type of lithium-ion secondary battery in each battery string St may be any type, and lithium-ion secondary batteries of various types may be mixed.

[0103] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the claims, not by the description of the embodiments described above, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0104] 1 power supply system, 2 first power supply circuit, 3 AC sweep unit, 10 first DC sweep unit, 11 first switching element, 12 second switching element, 13 first diode, 14 second diode, 15 choke coil, 16 capacitor, 20 second DC sweep unit, 30 third DC sweep unit, 50, 60, 70 inverter, 81 gate driver, 82 delay circuit, 100 GCU, 200 server, A1 to A6 SCU, B battery, BC battery circuit, BS monitoring unit, Cg cartridge, C1, C2 distribution board, D1 to D3 SCU, M battery circuit module, OT1, OT2 output terminal, PG power system, R1, R2 relay, RB1, RB2 circuit breaker, r4 to r9 relay, SUA drive circuit, SUB power circuit, SWL1, St battery string, SU sweep unit, T1, T2 Insulating filter.

Claims

1. an AC sweep unit that outputs AC power from the Y-connected U-phase battery string, the V-phase battery string, and the W-phase battery string; a first power supply circuit that converts an output of a DC sweep unit including a first battery string into AC power using an inverter and outputs the AC power; a control device that controls the AC sweep unit and the first power supply circuit, each of the U-phase battery string, the V-phase battery string, the W-phase battery string, and the first battery string includes a plurality of battery circuit modules connected in series; Each of the plurality of battery circuit modules is Batteries and an output terminal for outputting a voltage of the battery; a first switch connected to the output terminal and connected in parallel to the battery; a second switch connected in series with the battery; a voltage of the battery is applied to the output terminal when the first switch is in an OFF state and the second switch is in an ON state; The first power supply circuit and the AC sweep unit are configured to be electrically connectable to an external power supply; a power supply system, wherein an energy density of the batteries included in the U-phase battery string, the V-phase battery string, and the W-phase battery string is higher than an energy density of the batteries included in the first battery string.

2. 2 . The power supply system according to claim 1 , wherein a power density of the batteries included in the first battery string is higher than a power density of the batteries included in the U-phase battery string, the V-phase battery string, and the W-phase battery string.

3. the batteries included in the first battery string are nickel-metal hydride batteries, 3. The power supply system according to claim 1, wherein the batteries included in the U-phase battery string, the V-phase battery string, and the W-phase battery string are lithium ion batteries.

4. The control device includes: controlling the AC sweep unit and the first power supply circuit so as to adjust the power of the external power supply according to input / output power of the AC sweep unit and the first power supply circuit; If the power required by the power regulation is within a predetermined range, connect the AC sweep unit to the external power source, and perform the power regulation of the external power source by the AC sweep unit; 4. The power supply system according to claim 1, wherein when power required by the power adjustment exceeds the predetermined range, the first power supply circuit is connected to the external power supply in addition to the AC sweep unit, and the power adjustment of the external power supply is performed by the AC sweep unit and the first power supply circuit.

5. the batteries included in the U-phase battery string, the V-phase battery string, and the W-phase battery string are charged with power from the external power supply; 5. The power supply system according to claim 1, wherein the control device controls the AC sweep unit so that the storage amounts of the U-phase battery string, the V-phase battery string, and the W-phase battery string are the same.

6. the batteries included in the U-phase battery string, the V-phase battery string, and the W-phase battery string are charged with power from the external power supply; 6. The power supply system according to claim 1, wherein, when the batteries included in the U-phase battery string, the V-phase battery string, and the W-phase battery string are fully charged, the control device controls the AC sweep unit to turn on the first switch and turn off the second switch of the battery circuit module including the fully charged battery, thereby disconnecting the battery circuit module including the fully charged battery from the series connection.

7. The control device includes: detecting a degree of deterioration of the batteries included in the U-phase battery string, the V-phase battery string, and the W-phase battery string; 7. The power supply system according to claim 1, wherein the AC sweep unit controls the first switch of the battery circuit module including the battery whose degree of deterioration is greater than a predetermined value to be ON and the second switch to be OFF, thereby disconnecting the battery circuit module including the battery whose degree of deterioration is greater than a predetermined value from the series connection.

Images