Power supply system and control program

Abstract

To reduce the rating capacity of a conversion circuit in a power supply system in which a storage battery module is connected to a power supply bus.SOLUTION: In a power supply system (10), storage battery modules (30, 60) having storage batteries (31, 61) and conversion circuits (40, 70) are connected to power supply buses (11, 12). Positive electrodes and negative electrodes of the power storage batteries are connected to a pair of primary side terminals (41, 42, 71, 72) of the conversion circuits, respectively, and the storage batteries are serially connected to a pair of secondary side terminals (47, 48, 77, 78) of the conversion circuits. The power supply system comprises: a bus voltage setting unit (16a) that sets a bus voltage required value as a voltage required for each power supply bus; and a control unit (16b) that controls output voltages of the conversion circuits so that the output voltages of the storage battery modules are at the bus voltage required value. The bus voltage setting unit sets the bus voltage required value so that the output voltages of the conversion circuits are equal to or less than a rating voltage of the conversion circuits.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power supply system. [Background technology]

[0002] For example, there is a storage battery module in which the positive and negative electrodes of a storage battery are connected to a pair of input terminals of a conversion circuit, respectively, and the storage battery is connected in series to a pair of output terminals of the conversion circuit (see Patent Document 1). According to the storage battery module described in Patent Document 1, the output voltage Vm of the storage battery module is the sum of the output voltage Vb of the storage battery and the output voltage Vo of the conversion circuit. Therefore, compared to a storage battery module in which the storage battery is connected in parallel to the pair of output terminals of the conversion circuit, the output voltage Vo required of the conversion circuit can be reduced when the output voltage Vm is required of the storage battery module. Therefore, the rated capacity of the conversion circuit can be reduced. [Prior art documents] [Patent documents]

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

[0004] In the battery module described in Patent Document 1, the rated capacity of the conversion circuit can be reduced due to the effect of the circuit configuration of the battery module itself. However, as a power supply system in which the battery module is connected to a power supply bus, there is still room for improvement in terms of further reducing the rated capacity of the conversion circuit.

[0005] The present invention has been made to solve the above-mentioned problems, and its main object is to reduce the rated capacity of a conversion circuit in a power supply system in which a storage battery module is connected to a power supply bus. [Means for solving the problem]

[0006] The first means for solving the above problem is: a power supply system (10, 210) including a storage battery (31, 61, 91) and a conversion circuit (40, 70, 100) that converts power input from the storage battery to a pair of primary terminals (41, 42, 71, 72) and outputs the converted power from a pair of secondary terminals (47, 48, 77, 78), the storage battery module (30, 60, 90) being connected to a power supply bus (11, 12); a positive electrode and a negative electrode of the storage battery are connected to the primary terminal pair of the conversion circuit, and the storage battery is connected in series to the secondary terminal pair of the conversion circuit; a bus voltage setting unit (16a) that sets a bus voltage requirement value, which is a voltage required for the power supply bus; a control unit (16b) that controls the output voltage of the conversion circuit so that the output voltage of the storage battery module approaches the required bus voltage value; The bus voltage setting unit sets the required bus voltage value so that the output power of the conversion circuit is equal to or less than the rated power of the conversion circuit, or so that the output voltage of the conversion circuit is equal to or less than the rated voltage of the conversion circuit.

[0007] According to the above configuration, in the power supply system, a storage battery module including a storage battery and a conversion circuit that converts power input from the storage battery to a primary-side terminal pair and outputs the converted power from a secondary-side terminal pair is connected to a power supply bus. This allows power to be supplied from the storage battery module to the power supply bus. Note that the power supply bus is a power path (common power path) shared in the power supply system to connect multiple circuits, devices, and equipment to exchange power.

[0008] The positive and negative electrodes of the storage battery are connected to the primary terminal pair of the conversion circuit, respectively, and the storage battery is connected in series to the secondary terminal pair of the conversion circuit. With this configuration, the output voltage Vm of the storage battery module is the sum of the output voltage Vb of the storage battery and the output voltage Vo of the conversion circuit. Therefore, compared to a storage battery module in which the storage battery is connected in parallel to the secondary terminal pair of the conversion circuit, the output voltage Vo required of the conversion circuit when the output voltage Vm is required of the storage battery module can be reduced. Therefore, the rated voltage of the conversion circuit can be lowered, and therefore the rated capacity of the conversion circuit can be reduced.

[0009] Here, a bus voltage setting unit sets a bus voltage requirement value, which is a voltage required for the power supply bus. A control unit controls the output voltage Vo of the conversion circuit so that the output voltage Vm of the storage battery module approaches the bus voltage requirement value. Therefore, even if the output voltage Vb of the storage battery of the storage battery module decreases, the output voltage Vm of the storage battery module can be brought closer to the bus voltage requirement value by controlling the output voltage Vo of the conversion circuit.

[0010] In this case, if the output voltage Vo of the conversion circuit becomes high, the output voltage Vo of the conversion circuit may exceed the rated voltage of the conversion circuit. In this regard, the bus voltage setting unit sets the required bus voltage value so that the output power of the conversion circuit is equal to or less than the rated power of the conversion circuit, or so that the output voltage Vo of the conversion circuit is equal to or less than the rated voltage of the conversion circuit. Therefore, the rated voltage of the conversion circuit can be further reduced, and therefore the rated capacity (rated power capacity, rated power) of the conversion circuit can be further reduced. As a result, the conversion circuit can be made smaller.

[0011] In a second aspect, the bus voltage setting unit reduces the bus voltage request value below the current bus voltage request value when the output power of the conversion circuit exceeds a predetermined power value that is smaller than the rated power, when the output voltage of the conversion circuit exceeds the rated voltage, or when the output current of the conversion circuit exceeds a predetermined current value that is smaller than the rated current of the conversion circuit. With this configuration, when there is a risk that the output power of the conversion circuit will exceed the rated capacity, the bus voltage request value can be reduced below the current bus voltage request value. Therefore, the output voltage Vo of the conversion circuit can be reduced below the current output voltage Vo, preventing the output power of the conversion circuit from exceeding the rated capacity. Therefore, the rated capacity of the conversion circuit can be further reduced.

[0012] The third means includes a current adjustment unit (16c) that reduces the output current of the conversion circuit below its current output current when the output power of the conversion circuit exceeds a predetermined power value that is smaller than the rated power, when the output voltage of the conversion circuit exceeds the rated voltage, or when the output current of the conversion circuit exceeds a predetermined current value that is smaller than the rated current of the conversion circuit. With this configuration, when there is a risk that the output power of the conversion circuit will exceed its rated capacity, the output current of the conversion circuit can be reduced below its current output current. Therefore, the output power of the conversion circuit can be reduced below its current output power, preventing the output power of the conversion circuit from exceeding its rated capacity. Therefore, the rated capacity of the conversion circuit can be further reduced.

[0013] In a fourth means, the storage battery module is a first storage battery module (30) and is provided with a second storage battery module (60) corresponding to the storage battery module, and when the output power of the conversion circuit of the first storage battery module becomes equal to or greater than the predetermined power value, or when the output voltage of the conversion circuit of the first storage battery module becomes equal to or greater than the rated voltage, or when the output current of the conversion circuit of the first storage battery module becomes equal to or greater than the predetermined current value, the current adjustment unit reduces the output current of the conversion circuit of the first storage battery module below the current output current and increases the output current of the conversion circuit of the second storage battery module above the current output current.

[0014] According to the above configuration, the storage battery module is a first storage battery module, and the power supply system includes a second storage battery module corresponding to the storage battery module. Therefore, power can be supplied from the first storage battery module and the second storage battery module to the power supply bus. Furthermore, when there is a risk that the output power of the conversion circuit of the first storage battery module will exceed its rated capacity, the output current of the conversion circuit of the first storage battery module can be reduced below its current output current. Therefore, the output power of the conversion circuit of the first storage battery module can be reduced below its current output power, preventing the output power of the conversion circuit of the first storage battery module from exceeding its rated capacity. Therefore, the rated capacity of the conversion circuit of the first storage battery module can be further reduced.

[0015] Furthermore, when the output current of the conversion circuit of the first storage battery module is reduced below the current output current, the output current of the conversion circuit of the second storage battery module is increased above the current output current. Therefore, even if the output current of the conversion circuit of the first storage battery module is reduced, a decrease in the total current supplied from the first storage battery module and the second storage battery module to the power supply bus can be suppressed.

[0016] In a fifth means, the storage battery module is a first storage battery module (30) and is provided with a second storage battery module (60) corresponding to the storage battery module, and when the output power of the conversion circuit of the first storage battery module becomes equal to or greater than a predetermined power value that is smaller than the rated power, or when the output voltage of the conversion circuit of the first storage battery module becomes equal to or greater than the rated voltage, or when the output current of the conversion circuit of the first storage battery module becomes equal to or greater than a predetermined current value that is smaller than the rated current of the conversion circuit, the control unit charges the storage battery of the first storage battery module from the storage battery of the second storage battery module.

[0017] According to the above configuration, when there is a risk that the output power of the conversion circuit of the first storage battery module will exceed its rated capacity, the storage battery of the first storage battery module can be charged from the storage battery of the second storage battery module. This increases the charge amount of the storage battery of the first storage battery module, thereby increasing the output voltage Vb of the storage battery of the first storage battery module. Therefore, when the output voltage Vm is required of the first storage battery module, the output voltage Vo required of the conversion circuit of the first storage battery module can be reduced. As a result, the rated voltage of the conversion circuit of the first storage battery module can be further reduced, and thus the rated capacity of the conversion circuit of the first storage battery module can be further reduced.

[0018] The sixth aspect of the present invention includes a resistance adjustment unit (16d) that reduces the internal resistance of the storage battery of the storage battery module including the conversion circuit below its current internal resistance when the output power of the conversion circuit exceeds a predetermined power value lower than the rated power, when the output voltage of the conversion circuit exceeds the rated voltage, or when the output current of the conversion circuit exceeds a predetermined current value lower than the rated current of the conversion circuit. With this configuration, when there is a risk that the output power of the conversion circuit will exceed the rated capacity, the internal resistance of the storage battery of the storage battery module including the conversion circuit can be reduced below its current internal resistance. This reduces the voltage drop due to the internal resistance of the storage battery, thereby increasing the output voltage Vb of the storage battery. Therefore, when the output voltage Vm is required of the storage battery module, the output voltage Vo required of the conversion circuit can be reduced. As a result, the rated voltage of the conversion circuit can be further reduced, thereby further reducing the rated capacity of the conversion circuit.

[0019] Generally, the internal resistance of a storage battery correlates with the temperature of the storage battery. Therefore, in the seventh means, the resistance adjustment unit changes the temperature of the storage battery from the current temperature to reduce the internal resistance of the storage battery below the current internal resistance. With this configuration, the internal resistance of the storage battery can be reduced below the current internal resistance by utilizing the correlation between the internal resistance of the storage battery and the temperature of the storage battery. For example, if the internal resistance decreases as the temperature of the storage battery increases, the internal resistance of the storage battery can be reduced by increasing the current flowing through the storage battery or heating the storage battery with a heater.

[0020] In an eighth aspect, a predetermined storage battery module (120) including a storage battery (121) but not including the conversion circuit is connected to the power supply bus. With this configuration, power can be supplied from the predetermined storage battery module to the power supply bus. Furthermore, the storage battery module including the conversion circuit can adjust the output voltage Vm of the storage battery module to the output voltage Vmb of the predetermined storage battery module by controlling the output voltage Vo of the conversion circuit, which is added to the output voltage Vb of the storage battery. Therefore, it is possible to reduce the number of conversion circuits in the entire power supply system while suppressing inrush currents and circulating currents from flowing between the storage battery module and the predetermined storage battery module.

[0021] In a ninth aspect, a load (28) is connected to the battery module, and a disconnection circuit (22, 24, 25, 27) is provided for disconnecting and connecting the battery module and the load to and from the power supply bus.

[0022] According to the above configuration, by supplying power from the storage battery module to the load while the storage battery module and the load are disconnected from the power supply bus by the disconnection circuit, the charge amount of the storage battery of the storage battery module can be reduced. Reducing the charge amount of the storage battery can reduce the output voltage Vb of the storage battery. This makes it easier to reduce the output voltage Vb of the storage battery of the storage battery module below the output voltage Vb of the storage battery of a predetermined storage battery module. This makes it easier to control the addition of the output voltage Vo of the conversion circuit to the output voltage Vb of the storage battery of the storage battery module, and to adjust the output voltage Vm of the storage battery module to the output voltage Vmb of the predetermined storage battery module.

[0023] In a tenth aspect, a load (28) is connected to the power supply bus and the predetermined battery module, and includes a connection / disconnection circuit (120a, 120b) that disconnects and connects the predetermined battery module to the power supply bus and the load.

[0024] According to the above configuration, power can be supplied from a predetermined storage battery module to a load. Furthermore, if a failure occurs in a predetermined storage battery module, the predetermined storage battery module can be disconnected from the power supply bus and the load by a disconnection circuit. Even in this case, power can be supplied from the storage battery module to the power supply bus, thereby supplying power from the power supply bus to the load.

[0025] An eleventh aspect of the present invention includes a switching circuit (22-27, 211-214) that switches the storage battery module and the predetermined storage battery module between a parallel connection and a series connection. With this configuration, when the storage battery module and the predetermined storage battery module are switched to a parallel connection by the switching circuit, power can be supplied from the storage battery module and the predetermined storage battery module to a power supply bus. Therefore, the storage battery module and the predetermined storage battery module can be used as a redundant power source. Furthermore, when the storage battery module and the predetermined storage battery module are switched to a series connection by the switching circuit, a voltage obtained by adding the output voltage Vm of the storage battery module and the output voltage Vmb of the predetermined storage battery module can be supplied to the power supply bus. Therefore, the storage battery module and the predetermined storage battery module can be used as a higher-voltage power source.

[0026] A twelfth aspect of the present invention includes a plurality of the storage battery modules (30, 60, 90) and a switching circuit (22-27, 211-214) that switches the plurality of storage battery modules between parallel connection and series connection. With this configuration, when the plurality of storage battery modules are switched to parallel connection by the switching circuit, power can be supplied from the plurality of storage battery modules to a power supply bus. Therefore, the plurality of storage battery modules can be used as redundant power sources. Furthermore, when the plurality of storage battery modules are switched to series connection by the switching circuit, a voltage obtained by adding up the output voltages Vm of the plurality of storage battery modules can be supplied to the power supply bus. Therefore, the plurality of storage battery modules can be used as a higher-voltage power source.

[0027] The thirteenth measure is: A control program applied to a power supply system (10, 210) in which a storage battery module (30, 60, 90) including a storage battery (31, 61, 91) and a conversion circuit (40, 70, 100) that converts power input from the storage battery to a pair of primary terminals (41, 42, 71, 72) and outputs the converted power from a pair of secondary terminals (47, 48, 77, 78) is connected to a power supply bus (11, 12), and positive and negative electrodes of the storage battery are connected to the pair of primary terminals of the conversion circuit, respectively, and the storage battery is connected in series to the pair of secondary terminals of the conversion circuit, setting a bus voltage requirement value, which is a voltage required for the power supply bus; controlling the output voltage of the converter circuit so that the output voltage of the battery module approaches the required bus voltage; setting the bus voltage requirement value so that the output power of the conversion circuit is equal to or less than the rated power of the conversion circuit or so that the output voltage of the conversion circuit is equal to or less than the rated voltage of the conversion circuit; The computer (16) executes the following.

[0028] According to the above configuration, by causing a computer to execute a control program applied to the power supply system, it is possible to achieve the same effects as the first means. [Brief explanation of the drawings]

[0029] [Figure 1] Circuit diagram of the power supply system. [Figure 2] FIG. 1 is a circuit diagram showing an example of a conversion circuit. [Figure 3] 10 is a flowchart showing a procedure for controlling a bus voltage request value and an output current request value of a conversion circuit. [Figure 4] FIG. 4 is a circuit diagram showing a state in which the first output power of the first conversion circuit is large. [Figure 5] FIG. 10 is a circuit diagram showing a state in which the bus voltage requirement value is reduced. [Figure 6] FIG. 10 is a circuit diagram showing a state in which the first output current requirement value of the first conversion circuit is reduced. [Figure 7] FIG. 10 is a circuit diagram showing a state in which the first output current requirement value of the first conversion circuit is decreased and the second output current requirement value of the second conversion circuit is increased. [Figure 8] FIG. 10 is a circuit diagram showing a state in which the first storage battery is being charged from the second storage battery. [Figure 9] 10 is a circuit diagram showing a state in which the first storage battery is charged from the second storage battery and the required output current value of the first conversion circuit is reduced. [Figure 10] FIG. 10 is a circuit diagram of a modified example of a power supply system. [Figure 11] FIG. 10 is a circuit diagram of another modified example of the power supply system. [Figure 12] FIG. 10 is a circuit diagram of another modified example of the power supply system. [Figure 13] FIG. 10 is a circuit diagram of another modified example of the power supply system. [Figure 14] FIG. 10 is a circuit diagram of another modified example of the power supply system. [Figure 15] FIG. 10 is a circuit diagram of another modified example of the power supply system. [Figure 16] FIG. 10 is a circuit diagram of a modified example of the conversion circuit. [Figure 17] FIG. 10 is a circuit diagram of another modified example of the conversion circuit. [Figure 18] FIG. 10 is a circuit diagram of a modified example of the storage battery module. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, an embodiment of a power supply system for supplying power to a load will be described with reference to the drawings.

[0031] 1, a power supply system 10 includes buses 11 and 12 (power supply buses), a first storage battery module 30, a second storage battery module 60, a voltage sensor 13, a current sensor 19, an ECU (Electronic Control Unit) 16, etc. The positive side (positive side) of the bus is referred to as bus 11, and the negative side (negative side) of the bus is referred to as bus 12. Bus 12 is grounded.

[0032] A first storage battery module 30 (storage battery module), a second storage battery module 60 (storage battery module), a load 21, and a voltage sensor 13 are connected in parallel to the buses 11 and 12. The storage battery modules 30 and 60 input and output power to and from the buses 11 and 12. The load 21 inputs power from the buses 11 and 12, or inputs and outputs power to and from the buses 11 and 12. The voltage sensor 13 detects a bus voltage Vbus, which is the voltage between the bus 12 and the bus 11. The current sensor 19 detects a current flowing through the bus 12 (load 21).

[0033] The load 21 is, for example, a combination of an inverter and a motor generator (MG) (motor unit with inverter), an electric heater, a DC-DC converter, etc. The MG (motor generator) drives, for example, an electric vehicle using power supplied from the inverter, or performs regenerative power generation using rotational force applied from the electric vehicle. The inverter converts power between the buses 11, 12 and the MG. The electric heater generates heat using, for example, high voltage supplied from the buses 11, 12, and warms the interior of the vehicle or the battery. The DC-DC converter converts, for example, DC power supplied from the buses 11, 12 and supplies DC power, or converts DC power supplied from a solar panel or the like and supplies DC power to the buses 11, 12. The load 21 may be singular or plural.

[0034] The first storage battery module 30 includes a first storage battery 31, a first current sensor 33, a first drive circuit 35, a first conversion circuit 40, and relays 40a and 40b. The first storage battery 31 (storage battery) is a high-voltage secondary battery, such as a lithium-ion battery or a nickel-metal hydride battery, and may be of any type. The first current sensor 33 (current sensor) detects the current flowing through the first storage battery 31. The value detected by the first current sensor 33 is input to the ECU 16 and used, for example, to calculate the state of charge (SOC) of the first storage battery 31. The first drive circuit 35 (drive circuit) drives a switching element (described later) included in the first conversion circuit 40 to turn on and off. The first drive circuit 35 is controlled by the ECU 16. The relays 40a and 40b connect and disconnect the storage battery module 30 to and from the buses 11 and 12, respectively. The first storage battery 31 (storage battery) may be a secondary battery that is not a high voltage battery.

[0035] The first conversion circuit 40 (conversion circuit) includes a primary-side terminal pair consisting of a primary-side positive terminal 41 and a negative terminal 42, and a secondary-side terminal pair consisting of a secondary-side positive terminal 47 and a negative terminal 48. The negative terminal of the first storage battery 31 is connected to the bus 12. The primary-side positive terminal 41 is connected to the positive terminal of the first storage battery 31, and the primary-side negative terminal 42 is connected to the negative terminal of the first storage battery 31. Furthermore, the secondary-side negative terminal 48 is connected to the positive terminal of the first storage battery 31. The secondary-side positive terminal 47 is connected to the bus 11. That is, the positive and negative terminals of the first storage battery 31 are connected to the primary-side terminal pair 41, 42 of the first conversion circuit 40, respectively, and the first storage battery 31 is connected in series to the secondary-side terminal pair 47, 48 of the first conversion circuit 40. The first conversion circuit 40 converts the power input from the first storage battery 31 to the primary-side terminal pair 41, 42 and outputs it from the secondary-side terminal pair 47, 48. The first conversion circuit 40 is a bidirectional conversion circuit that can also convert the power input to the secondary-side terminal pair 47, 48 and output it from the primary-side terminal pair 41, 42.

[0036] The second storage battery module 60 has a configuration similar to that of the first storage battery module 30 and includes a second storage battery 61 (storage battery), a second current sensor 63 (current sensor), a second drive circuit 65 (drive circuit), a second conversion circuit 70, and relays 70a and 70b. The second conversion circuit 70 (conversion circuit) has a configuration similar to that of the first conversion circuit 40 and includes a primary-side terminal pair consisting of a primary-side positive terminal 71 and a negative terminal 72, and a secondary-side terminal pair consisting of a secondary-side positive terminal 77 and a negative terminal 78. The connection configuration of these components is also similar to that of the first storage battery module 30, and therefore the above description of the first storage battery module 30 is applicable. Although the first storage battery module 30 and the second storage battery module 60 have components with similar functions, the ratings and withstand voltages of the respective components may differ from each other.

[0037] FIG. 2 shows an example of a first conversion circuit 40. The first conversion circuit 40 is a well-known center-tap isolated DC-DC converter. The first conversion circuit 40 includes switching elements 43 to 46, 54, and 55, smoothing capacitors 50 and 57, a transformer 53, a reactor 56, voltage sensors 51 and 59, and current sensors 52 and 58. The switching elements 43 to 46, 54, and 55 are, for example, FETs or IGBTs (Insulated Gate Bipolar Transistors). The switching elements 43 to 46 form a full-bridge circuit. The connection point between the switching element 43 and the switching element 44 and the connection point between the switching element 45 and the switching element 46 are connected to both ends of the primary coil of the transformer 53, respectively. The switching elements 54 and 55 are connected between both ends of the secondary coil of the transformer 53 and the reactor 56, respectively. The voltage sensor 51 detects the voltage between the negative terminal 42 and the positive terminal 41 on the primary side, i.e., the output voltage Vb of the first storage battery 31. The current sensor 52 detects the input current Ii, which is the current input to the primary side circuit. The voltage sensor 59 detects the voltage between the negative terminal 48 and the positive terminal 47 on the secondary side, i.e., the output voltage Vo of the first conversion circuit 40. The current sensor 58 detects the current flowing through the reactor 56, i.e., the output current Io of the first conversion circuit 40. The detected values ​​of the voltage sensors 51, 59 and the current sensors 52, 58 are input to the ECU 16.

[0038] The ECU 16 (control device) is configured as a microcomputer (computer) including, for example, a CPU, a ROM, a RAM, an input / output interface, etc. The ECU 16 controls the states of the relays 15 and 17 and the state of the load 21. The ECU 16 executes a control program applied to the power supply system 10, thereby realizing the functions of a bus voltage setting unit 16a, a control unit 16b, a current adjusting unit 16c, a resistance adjusting unit 16d, etc.

[0039] The bus voltage setting unit 16a sets a bus voltage request value Vbus*, which is a voltage that is requested to be supplied from the buses 11 and 12 to the load 21. The bus voltage setting unit 16a sets the bus voltage request value Vbus* based on the state of the load 21.

[0040] The control unit 16b controls the output voltages Vo1 and Vo2 of the conversion circuits 40 and 70 so that the output voltages Vm1 and Vm2 of the storage battery modules 30 and 60 become the requested bus voltage value Vbus* (approach the requested bus voltage value Vbus*). For example, the control unit 16b controls the switching elements 43-46, 54, and 55 based on the detected values ​​of the voltage sensors 51 and 59 and the current sensors 52 and 58, thereby controlling the first output voltage Vo1 of the first conversion circuit 40 to become the requested first output voltage value Vo1* (approach the requested first output voltage value Vo1*). More specifically, the control unit 16b sets the requested first output voltage value Vo1* to a voltage obtained by subtracting the first output voltage Vb1 of the first storage battery 31 from the requested bus voltage value Vbus* (Vo1*=Vbus*−Vb1). Similarly, the control unit 16b controls the second output voltage Vo2 of the second conversion circuit 70 to become the second output voltage request value Vo2* (approach the second output voltage request value Vo2*). Specifically, the second output voltage request value Vo2* is set to a voltage obtained by subtracting the second output voltage Vb2 of the second storage battery 61 from the bus voltage request value Vbus* (Vo2*=Vbus*−Vb2).

[0041] Here, if the output voltages Vo1, Vo2 of the conversion circuits 40, 70 become high, there is a risk that the output voltages Vo1, Vo2 of the conversion circuits 40, 70 will exceed the rated voltage of the conversion circuits 40, 70. On the other hand, if the withstand voltage of the components of the conversion circuits 40, 70 is increased to increase the rated voltage of the conversion circuits 40, 70, the conversion circuits 40, 70 will become larger. Therefore, the bus voltage setting unit 16a sets the bus voltage request value Vbus* so that the output powers Po1, Po2 of the conversion circuits 40, 70 are equal to or less than the rated power (rated capacity) of the conversion circuits 40, 70, or so that the output voltages Vo1, Vo2 of the conversion circuits 40, 70 are equal to or less than the rated voltage of the conversion circuits 40, 70. Specifically, the ECU 16 executes the following control.

[0042] 3 is a flowchart showing a control procedure for the bus voltage request value Vbus* and the output current request values ​​Io1* and Io2* of the conversion circuits 40 and 70. This series of processes is repeatedly executed by the ECU 16 at predetermined intervals for each of the storage battery modules 30 and 60. Here, the process for the first storage battery module 30 will be described as an example.

[0043] First, it is determined whether the first output power Po1 of the first conversion circuit 40 is equal to or greater than a predetermined power value Pr (S10). The first output power Po1 is calculated by multiplying the first output current Io1 detected by the current sensor 58 of the first conversion circuit 40 by the first output voltage Vo1 detected by the voltage sensor 59 (Po1 = Io1 × Vo1). The predetermined power value Pr is set, for example, to a power value slightly smaller (a power value smaller by the difference) than the rated capacity Pc (rated power capacity, rated power) of the first conversion circuit 40. Note that the predetermined power value Pr can also be set to be equal to the rated capacity Pc. In this determination, if it is determined that the first output power Po1 of the first conversion circuit 40 is not equal to or greater than the predetermined power value Pr (S10: NO), this series of processes is temporarily terminated (END).

[0044] On the other hand, if it is determined in step S10 that the first output power Po1 of the first conversion circuit 40 is equal to or greater than the predetermined power value Pr (S10: YES), it is then determined whether the first output voltage Vo1 of the first conversion circuit 40 is equal to or greater than a predetermined voltage value Vr (S11). The predetermined voltage value Vr is set to, for example, the same as the rated voltage Vc of the first conversion circuit 40 (Vr = Vc). The predetermined voltage value Vr is a voltage lower than the withstand voltage of the first conversion circuit 40. If it is determined in this determination that the first output voltage Vo1 of the first conversion circuit 40 is equal to or greater than the predetermined voltage value Vr (S11: YES), the bus voltage request value Vbus* is reduced below the current bus voltage request value Vbus* (S12). For example, the bus voltage request value Vbus* is set to a voltage obtained by adding the rated voltage Vc of the first conversion circuit 40 to the first output voltage Vb1 of the first storage battery 31 (Vbus* = Vc + Vb1). At this time, the second output voltage Vo2 of the second conversion circuit 70 may be determined to be equal to or greater than a predetermined voltage value Vr, and Vbus* may be set to Vc+Vb2. In this case, the lower Vbus* between Vbus*=Vc+Vb1 and Vbus*=Vc+Vb2 is adopted. Note that in the process of S12, the bus voltage request value Vbus* may also be set to a voltage that is a predetermined value lower than the current bus voltage request value Vbus*. After that, this series of processes is temporarily terminated (END).

[0045] Furthermore, if it is determined in step S11 that the first output voltage Vo1 of the first conversion circuit 40 is not equal to or greater than the predetermined voltage value Vr (S11: NO), it is then determined whether the first output current Io1 of the first conversion circuit 40 is equal to or greater than a predetermined current value Ir (S13). The predetermined current value Ir is set, for example, to a current slightly smaller than the rated current Ic of the first conversion circuit 40 (a current smaller by the difference). The predetermined current value Ir can also be set to the same as the rated current Ic. If it is determined in this determination that the first output current Io1 of the first conversion circuit 40 is equal to or greater than the predetermined current value Ir (S13: YES), the first output current request value Io1* of the first conversion circuit 40 is reduced from the current first output current request value Io1* (S14). For example, the first output current request value Io1* is set to a current reduced by a predetermined value from the current first output current request value Io1*. This series of processes is then temporarily terminated (END).

[0046] On the other hand, if it is determined in S13 that the first output current Io1 of the first conversion circuit 40 is not equal to or greater than the predetermined current value Ir (S13: NO), this series of processes is temporarily terminated (END). Furthermore, this series of processes is also repeatedly executed at a predetermined interval by the ECU 16 for the second storage battery module 60. The processes of S10 to S12 correspond to the processes performed by the bus voltage setting unit 16a, and the processes of S13 and S14 correspond to the processes performed by the current adjusting unit.

[0047] Next, a description will be given of how the bus voltage request value Vbus* and the output current request values ​​Io1* and Io2* of the conversion circuits 40 and 70 are controlled by the series of processes shown in FIG.

[0048] FIG. 4 is a circuit diagram showing a state in which the first output power Po1 of the first conversion circuit 40 is large. Note that FIG. 4 shows a simplified connection of the conversion circuits 40, 70 (PPC: Partial Power Converter, partial boost converter). The storage battery modules 30, 60 include voltage sensors 31a, 61a that detect the voltages of the storage batteries 31, 61, respectively, and relays 40a, 40b, 70a, 70b (switches) that connect and disconnect the storage battery modules 30, 60 to and from the buses 11, 12, respectively. In this example, the output voltages Vb1, Vb2 of the storage batteries 31, 61 are 360 ​​[V] and 380 [V], respectively. The output currents Io1, Io2 of the conversion circuits 40, 70 are 100 [A] and 100 [A], respectively. The bus voltage request value Vbus* is 400 [V], and the output voltages Vo1 and Vo2 of the conversion circuits 40 and 70 are 40 [V] and 20 [V], respectively. As a result, a voltage of 400 [V] is applied to the load 21, and a current of 200 [A] flows through the load 21. The first output power Po1 of the first conversion circuit 40 is 100 [A] × 40 [V] = 4000 [W].

[0049] Here, assume that the first output power Po1 = 4000 [W] is equal to or greater than the predetermined power value Pr, and the first output voltage Vo1 = 40 [V] is equal to or greater than the predetermined voltage value Vr. In this case, for example, as shown in Figure 5, the bus voltage requirement value Vbus* is reduced to 380 [V]. As a result, the output voltage requirement values ​​Vo1* and Vo2* of the conversion circuits 40 and 70 are reduced to 20 [V] and 0 [V], respectively, and the output voltages Vo1 and Vo2 of the conversion circuits 40 and 70 are reduced to 20 [V] and 0 [V], respectively.

[0050] Alternatively, suppose that the first output power Po1=4000 [W] is equal to or greater than the predetermined power value Pr and the first output current Io1=100 [A] is equal to or greater than the predetermined current value Ir. In this case, for example, as shown in FIG. 6, the first output current request value Io1* is reduced to 50 [A]. As a result, the first output current Io1 of the first conversion circuit 40 is reduced to 50 [A].

[0051] The present embodiment described above in detail has the following advantages.

[0052] The positive and negative electrodes of the storage batteries 31 and 61 are connected to the primary-side terminal pairs 41, 42, 71, and 72 of the conversion circuits 40 and 70, respectively, and the storage batteries 31 and 61 are connected in series to the secondary-side terminal pairs 47, 48, 77, and 78 of the conversion circuits 40 and 70, respectively. With this configuration, the output voltages Vm1 and Vm2 of the storage battery modules 30 and 60 are obtained by adding the output voltages Vb1 and Vb2 of the storage batteries 31 and 61 to the output voltages Vo1 and Vo2 of the conversion circuits 40 and 70, respectively. Therefore, compared to a storage battery module in which the storage batteries 31 and 61 are connected in parallel to the secondary-side terminal pairs 47, 48, 77, and 78 of the conversion circuits 40 and 70, respectively, it is possible to reduce the output voltages Vo1 and Vo2 required of the conversion circuits 40 and 70 when the output voltages Vm1 and Vm2 are required of the storage battery modules 30 and 60, respectively. Therefore, the rated voltage Vc of the conversion circuits 40, 70 can be reduced, and therefore the rated capacity Pc of the conversion circuits 40, 70 can be reduced.

[0053] The bus voltage setting unit 16a sets a bus voltage request value Vbus*, which is the voltage required for the buses 11 and 12. The control unit 16b controls the output voltages Vo1 and Vo2 of the conversion circuits 40 and 70 so that the output voltages Vm1 and Vm2 of the storage battery modules 30 and 60 become equal to the bus voltage request value Vbus*. Therefore, even if the output voltages Vb1 and Vb2 of the storage batteries 31 and 61 of the storage battery modules 30 and 60 decrease, the output voltages Vm1 and Vm2 of the storage battery modules 30 and 60 can be adjusted to the bus voltage request value Vbus* by controlling the output voltages Vo1 and Vo2 of the conversion circuits 40 and 70.

[0054] If the output voltages Vo1, Vo2 of the conversion circuits 40, 70 become high, there is a risk that the output voltages Vo1, Vo2 of the conversion circuits 40, 70 will exceed the rated voltage Vc of the conversion circuits 40, 70. In this regard, the bus voltage setting unit 16a sets the bus voltage request value Vbus* so that the output powers Po1, Po2 of the conversion circuits 40, 70 are equal to or less than the rated capacity Pc of the conversion circuits 40, 70, or so that the output voltages Vo1, Vo2 of the conversion circuits 40, 70 are equal to or less than the rated voltage Vc of the conversion circuits 40, 70. Therefore, the rated voltage Vc of the conversion circuits 40, 70 can be further reduced, and therefore the rated capacity Pc of the conversion circuits 40, 70 can be further reduced. As a result, the conversion circuits 40, 70 can be made smaller.

[0055] The bus voltage setting unit 16a reduces the bus voltage request value Vbus* below the current bus voltage request value Vbus* when the output powers Po1 and Po2 of the conversion circuits 40 and 70 are equal to or greater than the predetermined power value Pr and when the output voltages Vo1 and Vo2 of the conversion circuits 40 and 70 are equal to or greater than the predetermined voltage value Vr. This configuration allows the bus voltage request value Vbus* to be reduced below the current bus voltage request value Vbus* when there is a risk that the output powers Po1 and Po2 of the conversion circuits 40 and 70 will exceed the rated capacity Pc. This reduces the output voltages Vo1 and Vo2 of the conversion circuits 40 and 70 below the current output voltages Vo1 and Vo2, respectively, preventing the output powers Po1 and Po2 of the conversion circuits 40 and 70 from exceeding the rated capacity Pc. This reduces the rated capacity Pc of the conversion circuits 40 and 70.

[0056] The current adjusting unit 16c reduces the output currents Io1 and Io2 of the conversion circuits 40 and 70 from their current values ​​when the output powers Po1 and Po2 of the conversion circuits 40 and 70 are equal to or greater than a predetermined power value Pr and when the output currents Io1 and Io2 of the conversion circuits 40 and 70 are equal to or greater than a predetermined current value Ir. This configuration allows the output currents Io1 and Io2 of the conversion circuits 40 and 70 to be reduced from their current values ​​when there is a risk that the output powers Po1 and Po2 of the conversion circuits 40 and 70 will exceed the rated capacity Pc. This reduces the output powers Po1 and Po2 of the conversion circuits 40 and 70 from their current values, preventing the output powers Po1 and Po2 of the conversion circuits 40 and 70 from exceeding the rated capacity Pc. This reduces the rated capacity Pc of the conversion circuits 40 and 70.

[0057] The above-mentioned effects can be achieved by causing the ECU 16 (computer) to execute the control program applied to the power supply system 10.

[0058] The above embodiment can be modified as follows: The same parts as those in the above embodiment are denoted by the same reference numerals and the description thereof will be omitted.

[0059] 4, assume that the first output power Po1 = 4000 [W] is equal to or greater than the predetermined power value Pr, and the first output current Io1 = 100 [A] is equal to or greater than the predetermined current value Ir. In this case, as shown in FIG. 7, the current adjuster 16c may reduce the first output current request value Io1* to 50 [A] and increase the second output current request value Io2* to 150 [A]. Note that the second output power Po2 = 150 [A] × 20 [V] = 3000 [W] of the second conversion circuit 70 is smaller than the predetermined power value Pr. As a result, the first output current Io1 of the first conversion circuit 40 is reduced to 50 [A], and the second output current Io2 of the second conversion circuit 70 is increased to 150 [A]. As a result, a current of 200 [A] can be supplied to the load 21, as in FIG. 4. With this configuration, even if the first output current Io1 of the first conversion circuit 40 of the first storage battery module 30 is reduced, the total current supplied from the first storage battery module 30 and the second storage battery module 60 to the buses 11 and 12 can be prevented from decreasing.

[0060] 4, it is assumed that the first output power Po1 = 4000 [W] is equal to or greater than the predetermined power value Pr, and the first output voltage Vo1 = 40 [V] is equal to or greater than the predetermined voltage value Vr. In this case, as shown in FIG. 8, for example, the control unit 16b may charge the first storage battery 31 of the first storage battery module 30 from the second storage battery 61 of the second storage battery module 60. This increases the charge amount of the first storage battery 31 of the first storage battery module 30, and increases the first output voltage Vb1 of the first storage battery 31 of the first storage battery module 30 from, for example, 360 [V] (see FIG. 4) to 370 [V]. Note that the second output voltage Vb2 of the second storage battery 61 of the second storage battery module 60 decreases from, for example, 380 [V] (see FIG. 4) to 370 [V]. Therefore, when a first output voltage Vm1=400 V is required of the first storage battery module 30, it is possible to reduce the first output voltage Vo1 required of the first conversion circuit 40 of the first storage battery module 30. As a result, it is possible to further reduce the rated voltage Vc of the first conversion circuit 40 of the first storage battery module 30, and therefore the rated capacity Pc of the first conversion circuit 40 of the first storage battery module 30.

[0061] 9 , the current adjusting unit 16c may reduce the load current request value It*, which is the current required by the load 21, to 150 [A] and reduce the first output current request value Io1* to 50 [A]. This reduces the first output current Io1 of the first conversion circuit 40 to 50 [A]. As a result, the rated current Ic of the first conversion circuit 40 of the first storage battery module 30 can also be reduced, and therefore the rated capacity Pc of the first conversion circuit 40 of the first storage battery module 30 can be further reduced.

[0062] 1, the ECU 16 of the power supply system 10 may include a resistance adjuster 16d. The resistance adjuster 16d reduces the internal resistance of the storage batteries 31, 61 of the storage battery modules 30, 60 below their current internal resistances. Specifically, the resistance adjuster 16d reduces the internal resistance of the storage batteries 31, 61 below their current internal resistances by changing the temperatures of the storage batteries 31, 61 from their current temperatures. For example, if the internal resistance of the storage batteries 31, 61 decreases as the temperature of the storage batteries 31, 61 increases, the internal resistance of the storage batteries 31, 61 can be reduced by increasing the current flowing through the storage batteries 31, 61 or by heating the storage batteries 31, 61 with a heater.

[0063] In FIG. 4 , assume that the first output power Po1=4000 [W] is equal to or greater than the predetermined power value Pr, and the first output voltage Vo1=40 [V] is equal to or greater than the predetermined voltage value Vr. In this case, the resistance adjuster 16d reduces the internal resistance of the first storage battery 31 of the first storage battery module 30 below its current internal resistance. This configuration reduces the voltage drop due to the internal resistance of the first storage battery 31, thereby increasing the first output voltage Vb1 of the first storage battery 31. Therefore, when the first output voltage Vm1 is required of the first storage battery module 30, the first output voltage Vo1 required of the first conversion circuit 40 can be reduced. As a result, the rated voltage Vc of the first conversion circuit 40 can be further reduced, and thus the rated capacity Pc of the first conversion circuit 40 can be further reduced.

[0064] If the internal resistance of the storage batteries 31, 61 increases as the temperature of the storage batteries 31, 61 increases, the internal resistance of the storage batteries 31, 61 can be reduced by reducing the current flowing through the storage batteries 31, 61 or by cooling the storage batteries 31, 61 with a cooling circuit. Furthermore, the internal resistance of the storage batteries 31, 61 may be reduced when the output voltages Vo1, Vo2 of the conversion circuits 40, 70 are increased to increase the bus voltage Vbus. Furthermore, the internal resistance of the storage batteries 31, 61 may be increased when the output voltages Vo1, Vo2 of the conversion circuits 40, 70 are decreased to decrease the bus voltage Vbus.

[0065] Not only when the first output power Po1 is equal to or greater than the predetermined power value Pr and the first output voltage Vo1 is equal to or greater than the predetermined voltage value Vr, but also when the first output power Po1 is simply equal to or greater than the predetermined power value Pr, the bus voltage request value Vbus* may be reduced to be lower than the current bus voltage request value Vbus*, the first output current Io1 of the first conversion circuit 40 may be reduced to be lower than the current first output current Io1, the second storage battery 61 of the second storage battery module 60 may be charged to the first storage battery 31 of the first storage battery module 30, or the internal resistance of the first storage battery 31 may be reduced to be lower than the current internal resistance. Alternatively, simply when the first output voltage Vo1 is equal to or greater than the predetermined voltage value Vr, the bus voltage request value Vbus* may be reduced below the current bus voltage request value Vbus*, the first output current Io1 of the first conversion circuit 40 may be reduced below the current first output current Io1, the first storage battery 31 of the first storage battery module 30 may be charged from the second storage battery 61 of the second storage battery module 60, or the internal resistance of the first storage battery 31 may be reduced below the current internal resistance. Alternatively, simply when the first output current Io1 is equal to or greater than the predetermined current value Ir, the bus voltage request value Vbus* may be reduced below the current bus voltage request value Vbus*, the first output current Io1 of the first conversion circuit 40 may be reduced below the current first output current Io1, the first storage battery 31 of the first storage battery module 30 may be charged from the second storage battery 61 of the second storage battery module 60, or the internal resistance of the first storage battery 31 may be reduced below the current internal resistance. In the above case, when the first output current Io1 of the first conversion circuit 40 is reduced to be less than the current first output current Io1, the second output current Io2 of the second conversion circuit 70 may be increased to be more than the current second output current Io2. The same applies to the second storage battery module 60.

[0066] When the bus voltage setting unit 16a reduces the bus voltage request value Vbus* below the current bus voltage request value Vbus*, the bus voltage setting unit 16a may reduce the bus voltage request value Vbus* to a level that does not cause the bus voltage Vbus to fall below the minimum voltage required by the load 21.

[0067] When reducing the output currents Io1, Io2 of the conversion circuits 40, 70 below the current output currents Io1, Io2, the current adjustment unit 16c may reduce the output current requirement values ​​Io1*, Io2* to the extent that the sum of the output currents Io1, Io2 does not fall below the minimum current required by the load 21.

[0068] As shown in FIG. 10 , a predetermined storage battery module 120 including a storage battery 121 but no conversion circuit may be connected to the buses 11 and 12. The predetermined storage battery module 120 includes a voltage sensor 121a that detects the voltage of the storage battery 121 and relays 120a and 120b that connect and disconnect the predetermined storage battery module 120 to and from the buses 11 and 12, respectively. This configuration allows power to be supplied from the predetermined storage battery module 120 to the buses 11 and 12. Furthermore, the storage battery modules 30 and 60 each including a conversion circuit 40 and 70 can adjust the output voltages Vm1 and Vm2 of the storage battery modules 30 and 60 to, for example, the output voltage Vmb of the predetermined storage battery module 120, for example, 400 V, by controlling the output voltages Vo1 and Vo2 of the conversion circuits 40 and 70 that are added to the output voltages Vb1 and Vb2 of the storage batteries 31 and 61, respectively. Therefore, it is possible to reduce the number of conversion circuits in the entire power supply system 210, while suppressing the flow of inrush current and circulating current between the storage battery modules 30, 60 and the predetermined storage battery module 120. As a result, it is possible to further reduce the size of the power supply system 210.

[0069] In the power supply system 210, the same control as that of the power supply system 10 and its modified example can be executed in a state in which the relays 120a and 120b disconnect the predetermined storage battery module 120 from the buses 11 and 12. Furthermore, the controls of reducing the first output current Io1 of the first conversion circuit 40 to be lower than the current first output current Io1, charging the first storage battery 31 of the first storage battery module 30 from the storage battery 121 of the predetermined storage battery module 120, and lowering the internal resistance of the first storage battery 31 to be lower than the current internal resistance can also be executed in a state in which the relays 120a and 120b connect the predetermined storage battery module 120 to the buses 11 and 12.

[0070] 11 , the power supply system 10 may include a path 22 connecting the positive electrode (positive side) of the first storage battery module 30 to the bus 11, a path 24 connecting the negative electrode (negative side) of the second storage battery module 60 to the bus 12, and a path 23 connecting the path 22 and the path 24. The path 22 includes a relay 25 (switch) for connecting and disconnecting the path 22 between a connection point N1 between the path 22 and the path 23 and a connection point N2 between the path 22 and the bus 11. The path 23 includes a relay 26 (switch) for connecting and disconnecting the path 23. The path 24 includes a relay 27 (switch) for connecting and disconnecting the path 24 between a connection point N3 between the path 24 and the path 23 and a connection point N4 between the path 24 and the bus 12. The relays 25 to 27 are controlled by the ECU 16. The paths 22 to 24 and the relays 25 to 27 form a switching circuit.

[0071] According to the above configuration, the ECU 16 can switch the parallel connection of the first storage battery module 30 and the second storage battery module 60 to the buses 11 and 12 by turning on (connecting) the relays 25 and 27 and turning off (connecting) the relay 26. The ECU 16 can also switch the series connection of the first storage battery module 30 and the second storage battery module 60 to the buses 11 and 12 by turning off (disconnecting) the relays 25 and 27 and turning on (connecting) the relay 26. That is, the switching circuit switches the series connection and parallel connection of the storage battery modules 30 and 60 to the buses 11 and 12. When the switching circuit switches the parallel connection of the storage battery modules 30 and 60, power can be supplied from the storage battery modules 30 and 60 to the buses 11 and 12. This allows the storage battery modules 30 and 60 to be used as redundant power sources. Then, when the storage battery modules 30, 60 are switched to a parallel connection by the switching circuit, the ECU 16 can execute the above-described control of the power supply system 10 and control similar to the modified example. When the storage battery modules 30, 60 are switched to a series connection by the switching circuit, the ECU 16 can supply the sum of the output voltages Vm1, Vm2 of the storage battery modules 30, 60 to the buses 11, 12. This allows the storage battery modules 30, 60 to be used as a higher-voltage power supply.

[0072] As shown in FIG. 12 , the power supply system 10 may include a predetermined storage battery module 120 instead of the second storage battery module 60 of FIG. 11 . A load 28 may be connected in parallel to the first storage battery module 30. The load 28 is the same as the load 21, and some of the multiple loads 21 may be used as the load 28. The load 28 is connected to a connection point N5 on the path 22 that is closer to the first storage battery module 30 than the relay 25, and a connection point N6 on the path 24 that is closer to the first storage battery module 30 than the relay 27. The paths 22 and 24 and the relays 25 and 27 form a connect / disconnect circuit. The paths 22 to 24 and the relays 25 to 27 form a switching circuit that switches between a series connection and a parallel connection of the first storage battery module 30 (storage battery module) and the predetermined storage battery module 120 with respect to the buses 11 and 12.

[0073] According to the above configuration, the ECU 16 can disconnect the first storage battery module 30 and the load 28 from the buses 11 and 12 by turning off (disconnecting) the relays 25 to 27. Then, in a state in which the first storage battery module 30 and the load 28 are disconnected from the buses 11 and 12 by the disconnecting circuit, the ECU 16 can supply power from the first storage battery module 30 to the load 28, thereby reducing the charge amount of the first storage battery 31 of the first storage battery module 30. Then, by reducing the charge amount of the first storage battery 31, the first output voltage Vb1 of the first storage battery 31 can be reduced. Therefore, the first output voltage Vb1 of the first storage battery 31 of the first storage battery module 30 can be more easily reduced below the output voltage Vmb of the storage battery 121 of the predetermined storage battery module 120. This makes it easier to perform control to add the first output voltage Vo1 of the first conversion circuit 40 to the first output voltage Vb1 of the first storage battery 31 in the first storage battery module 30, and makes it easier to adjust the first output voltage Vm1 of the first storage battery module 30 to the output voltage Vmb of the predetermined storage battery module 120. Note that by omitting the path 23 and the relay 26, the power supply system 10 can be provided with only a disconnecting circuit and not a switching circuit.

[0074] As shown in Fig. 13, the power supply system 10 may include a predetermined storage battery module 120 instead of the first storage battery module 30 of Fig. 11. A load 28 may be connected in parallel to the predetermined storage battery module 120. The load 28 is connected to a connection point N5 on the path 22 that is closer to the predetermined storage battery module 120 than the relay 25, and to a connection point N6 on the path 24 that is closer to the predetermined storage battery module 120 than the relay 27. The relays 120a and 120b form a disconnection circuit. The paths 22 to 24 and the relays 25 to 27 form a switching circuit that switches between a series connection and a parallel connection of the second storage battery module 60 (storage battery module) and the predetermined storage battery module 120 with respect to the buses 11 and 12.

[0075] According to the above configuration, the ECU 16 can supply power from the predetermined storage battery module 120 to the load 28 by turning on (connecting) the relays 120a and 120b. Furthermore, when a failure occurs in the predetermined storage battery module 120, the ECU 16 can disconnect the predetermined storage battery module 120 from the buses 11 and 12 and the load 28 by turning off (disconnecting) the relays 120a and 120b. Furthermore, the ECU 16 can turn on the relays 25 and 27 and turn off the relay 26. Therefore, power can be supplied from the second storage battery module 60 to the buses 11 and 12, and power can be supplied from the buses 11 and 12 to the load 28.

[0076] 14, the load 28 may be connected in parallel to the second storage battery 61 (storage battery) of the second storage battery module 60 (storage battery module). In this case, the charge amount of the second storage battery 61 can be reduced by supplying power from the second storage battery 61 to the load 28. This makes it easier to reduce the second output voltage Vb2 of the second storage battery 61 in the second storage battery module 60 to a value lower than the first output voltage Vb1 of the first storage battery 31 in the first storage battery module 30. This makes it easier to perform control to add the second output voltage Vo2 of the second conversion circuit 70 to the second output voltage Vb2 of the second storage battery 61 in the second storage battery module 60, thereby regulating the second output voltage Vm2 of the second storage battery module 60 to the bus voltage request value Vbus*.

[0077] As shown in FIG. 15 , the power supply system 210 may include a third storage battery module 90 instead of the predetermined storage battery module 120 of FIG. 10 . The power supply system 210 may include a path 211 connecting a connection point N7 between the third conversion circuit 100 of the third storage battery module 90 and the relay 90a to a connection point N8 between the first storage battery 31 of the first storage battery module 30 and the relay 40b. The power supply system 210 may also include a path 213 connecting a connection point N9 between the first conversion circuit 40 of the first storage battery module 30 and the relay 40a to a connection point N10 between the second storage battery 61 of the second storage battery module 60 and the relay 70b. The path 211 is provided with a relay 212 (switch) that connects and disconnects the path 211. The path 213 is provided with a relay 214 (switch) that connects and disconnects the path 213. The relays 212 and 214 are controlled by the ECU 16. The paths 211, 213 and the relays 212, 214 form a switching circuit. That is, the power supply system 210 may include three or more storage battery modules (a plurality of storage battery modules), and the switching circuit may switch the three or more storage battery modules between series connection and parallel connection with the buses 11, 12. Also, any one of the storage battery modules 30, 60, 90 may be replaced with a predetermined storage battery module 120.

[0078] As the load 21, for example, two or more combinations of an inverter and an MG (Motor Generator) (motor unit with inverter) may be connected in parallel to the buses 11 and 12. In this case, the more motor units with inverters there are, the more storage battery modules may be connected to the buses 11 and 12.

[0079] The bus voltage setting unit 16a may also employ the following configuration to set the bus voltage request value Vbus* so that the output voltages Vo1, Vo2, and Vo3 of the conversion circuits 40, 70, and 100 are equal to or less than the rated voltage Vc of the conversion circuits 40, 70, and 100. Instead of performing the determinations in S10 and S11 of FIG. 3 , the bus voltage setting unit 16a may always set the bus voltage request value Vbus* equal to or less than an upper limit voltage value Vu1, which is the sum of the rated voltage Vc of the first conversion circuit 40 and the first output voltage Vb1 of the first storage battery 31. In other words, the bus voltage request value Vbus* may be upper-limit-guarded by the upper limit voltage value Vu1. With this configuration, the first output voltage Vo1 of the first conversion circuit 40 can be reduced before it exceeds the rated voltage Vc. If the second storage battery module 60, the third storage battery module 90, etc. are present, the bus voltage request value Vbus* may be limited to the lowest upper limit voltage value Vun among the upper limit voltage values ​​Vu2, Vu3, ..., Vun of the second storage battery module 60, the third storage battery module 90, etc. Furthermore, the first output voltage Vb1, the second output voltage Vb2, ..., the n-th output voltage Vbn may be voltage values ​​detected by the voltage sensor 51, or may be predicted values ​​based on correlation values ​​correlated with the first output voltage Vb1, the second output voltage Vb2, ..., the n-th output voltage Vbn.

[0080] As shown in Fig. 16, in the first conversion circuit 40 (conversion circuit), the switching elements 54 and 55 in Fig. 2 may be connected between the transformer 53 and the negative terminal 48. With this configuration, it is possible to achieve the same effects as the first conversion circuit 40 in Fig. 2. The same applies to the second conversion circuit 70 and the third conversion circuit 100 (conversion circuits).

[0081] 17, the first conversion circuit 40 (conversion circuit) may be a well-known isolated DC-DC converter including a non-center-tapped transformer 153 and a secondary-side full-bridge circuit composed of switching elements 143 to 146. The switching elements 143 to 146 are, for example, FETs or IGBTs (Insulated Gate Bipolar Transistors). The switching elements 143 to 146 are controlled by the ECU 16. The same applies to the second conversion circuit 70 and the third conversion circuit 100 (conversion circuits).

[0082] A resonant DC-DC converter can be used as the first conversion circuit 40 (conversion circuit). Also, a non-isolated DC-DC converter such as a buck converter can be used as the first conversion circuit 40 (conversion circuit). The same applies to the second conversion circuit 70 and the third conversion circuit 100 (conversion circuit).

[0083] 18, the storage battery modules 30, 60 may be configured as shown in FIG. 18. That is, the positive electrode of the first storage battery 31 is connected to the bus 11. The positive electrode of the first storage battery 31 is connected to a primary-side positive terminal 41 of a first conversion circuit 40, and the negative electrode of the first storage battery 31 is connected to a primary-side negative terminal 42 of the first conversion circuit 40. The negative electrode of the first storage battery 31 is connected to a secondary-side positive terminal 47 of the first conversion circuit 40. The secondary-side negative terminal 48 of the first conversion circuit 40 is connected to the bus 12. In this case, too, the positive and negative electrodes of the first storage battery 31 are connected to the primary-side terminal pair 41, 42 of the first conversion circuit 40, respectively, and the first storage battery 31 is connected in series to the secondary-side terminal pair 47, 48 of the first conversion circuit 40. With this configuration, the same effects as those of the above embodiment can be achieved. The same applies to the second storage battery module 60, the third storage battery module 90, etc. (storage battery modules). At least one of the functions of the bus voltage setting unit 16a, the control unit 16b, the current adjustment unit 16c, and the resistance adjustment unit 16d of the ECU 16 can be realized by, for example, a power control ECU (Electronic Control Unit) that controls the power of the electric vehicle or a vehicle control ECU (host ECU) that controls the electric vehicle. Furthermore, when the power supply system 10, 210 is used as, for example, a stationary power source, the functions of the bus voltage setting unit 16a, the control unit 16b, the current adjustment unit 16c, and the resistance adjustment unit 16d of the ECU 16 can be realized by a stationary power source control ECU (control device) that controls the stationary power source.

[0084] The ECU 16 and methods described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to execute one or more functions (instructions) embodied in a computer program. Alternatively, the ECU 16 and methods described herein may be implemented by a special-purpose computer configured with a processor implemented by one or more dedicated hardware logic circuits. Alternatively, the ECU 16 and methods described herein may be implemented by one or more special-purpose computers configured with a processor and memory programmed to execute one or more functions and a processor implemented by one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium.

[0085] The above-described embodiment and modifications may be combined within the scope of possible combinations.

[0086] Characteristic configurations extracted from the above-described embodiment and modified examples will be described below. [Configuration 1] a power supply system (10, 210) including a storage battery (31, 61, 91) and a conversion circuit (40, 70, 100) that converts power input from the storage battery to a pair of primary terminals (41, 42, 71, 72) and outputs the converted power from a pair of secondary terminals (47, 48, 77, 78), the storage battery module (30, 60, 90) being connected to a power supply bus (11, 12); a positive electrode and a negative electrode of the storage battery are connected to the primary terminal pair of the conversion circuit, and the storage battery is connected in series to the secondary terminal pair of the conversion circuit; a bus voltage setting unit (16a) that sets a bus voltage requirement value, which is a voltage required for the power supply bus; a control unit (16b) that controls the output voltage of the conversion circuit so that the output voltage of the storage battery module approaches the required bus voltage value; A power supply system in which the bus voltage setting unit sets the bus voltage requirement value so that the output power of the conversion circuit is equal to or less than the rated power of the conversion circuit, or so that the output voltage of the conversion circuit is equal to or less than the rated voltage of the conversion circuit. [Configuration 2] The power supply system of configuration 1, wherein the bus voltage setting unit reduces the bus voltage request value below the current bus voltage request value when the output power of the conversion circuit becomes equal to or greater than a predetermined power value that is smaller than the rated power, when the output voltage of the conversion circuit becomes equal to or greater than the rated voltage, or when the output current of the conversion circuit becomes equal to or greater than a predetermined current value that is smaller than the rated current of the conversion circuit. [Configuration 3] The power supply system according to configuration 1 or 2, further comprising a current adjusting unit (16c) that reduces the output current of the conversion circuit below a current output current when the output power of the conversion circuit becomes equal to or greater than a predetermined power value that is smaller than the rated power, when the output voltage of the conversion circuit becomes equal to or greater than the rated voltage, or when the output current of the conversion circuit becomes equal to or greater than a predetermined current value that is smaller than the rated current of the conversion circuit. [Configuration 4] the battery module is a first battery module (30); a second storage battery module (60) corresponding to the storage battery module; The power supply system of configuration 3, wherein when the output power of the conversion circuit of the first storage battery module becomes equal to or greater than the predetermined power value, when the output voltage of the conversion circuit of the first storage battery module becomes equal to or greater than the rated voltage, or when the output current of the conversion circuit of the first storage battery module becomes equal to or greater than the predetermined current value, the current adjustment unit reduces the output current of the conversion circuit of the first storage battery module to be less than the current output current, and increases the output current of the conversion circuit of the second storage battery module to be less than the current output current. [Configuration 5] the battery module is a first battery module (30); a second storage battery module (60) corresponding to the storage battery module; The power supply system of any one of configurations 1 to 4, wherein the control unit charges the storage battery of the first storage battery module from the storage battery of the second storage battery module when the output power of the conversion circuit of the first storage battery module becomes equal to or greater than a predetermined power value that is smaller than the rated power, when the output voltage of the conversion circuit of the first storage battery module becomes equal to or greater than the rated voltage, or when the output current of the conversion circuit of the first storage battery module becomes equal to or greater than a predetermined current value that is smaller than the rated current of the conversion circuit. [Configuration 6] The power supply system according to any one of configurations 1 to 5, further comprising a resistance adjustment unit (16d) that reduces the internal resistance of the storage battery of the storage battery module including the conversion circuit below the current internal resistance when the output power of the conversion circuit becomes equal to or greater than a predetermined power value that is smaller than the rated power, when the output voltage of the conversion circuit becomes equal to or greater than the rated voltage, or when the output current of the conversion circuit becomes equal to or greater than a predetermined current value that is smaller than the rated current of the conversion circuit. [Configuration 7] 7. The power supply system according to claim 6, wherein the resistance adjusting unit changes the temperature of the storage battery from a current temperature to reduce the internal resistance of the storage battery below the current internal resistance. [Configuration 8] 4. The power supply system according to any one of configurations 1 to 3, wherein a predetermined battery module (120) including a battery (121) but not including the conversion circuit is connected to the power supply bus. [Configuration 9] A load (28) is connected to the battery module; 9. The power supply system according to claim 8, further comprising a connection / disconnection circuit (22, 24, 25, 27) for disconnecting and connecting the battery module and the load to the power supply bus. [Configuration 10] a load (28) connected to the power supply bus and the selected battery module; 9. The power supply system according to configuration 8, further comprising a connection / disconnection circuit (120a, 120b) that disconnects and connects the predetermined storage battery module to the power supply bus and the load. [Configuration 11] 11. The power supply system according to any one of configurations 8 to 10, further comprising a switching circuit (22 to 27, 211 to 214) that switches the storage battery module and the predetermined storage battery module between parallel connection and series connection. [Configuration 12] A plurality of the storage battery modules (30, 60, 90) are provided, The power supply system according to any one of configurations 1 to 7, further comprising a switching circuit (22 to 27, 211 to 214) that switches the plurality of storage battery modules between parallel connection and series connection. [Explanation of symbols]

[0087] 10...power supply system, 11...bus, 12...bus, 16...ECU, 16a...bus voltage setting unit, 16b...control unit, 30...first storage battery module, 31...first storage battery, 40...first conversion circuit, 41...positive terminal (primary side terminal pair), 42...negative terminal (primary side terminal pair), 47...positive terminal (secondary side terminal pair), 48...negative terminal (secondary side terminal pair), 60...second storage battery module, 61...second storage battery, 70...second conversion circuit, 71...positive terminal (primary side terminal pair), 72...negative terminal (primary side terminal pair), 77...positive terminal (secondary side terminal pair), 78...negative terminal (secondary side terminal pair), 90...third storage battery module, 100...third conversion circuit, 210...power supply system.

Claims

1. A power supply system (10, 210) including a storage battery (31, 61, 91) and a conversion circuit (40, 70, 100) that converts power input from the storage battery to a primary side terminal pair (41, 42, 71, 72) and outputs the power from a secondary side terminal pair (47, 48, 77, 78), the storage battery module (30, 60, 90) being connected to a power supply bus (11, 12), a positive electrode and a negative electrode of the storage battery are respectively connected to the primary terminal pair of the conversion circuit, and the storage battery is connected in series to the secondary terminal pair of the conversion circuit; a bus voltage setting unit (16a) for setting a bus voltage requirement value which is a voltage required for the power supply bus; a control unit (16b) for controlling an output voltage of the conversion circuit so that an output voltage of the storage battery module approaches the bus voltage request value; A power supply system in which the bus voltage setting unit sets the bus voltage requirement value so that the output power of the conversion circuit is equal to or less than the rated power of the conversion circuit, or so that the output voltage of the conversion circuit is equal to or less than the rated voltage of the conversion circuit.

2. The power supply system of claim 1, wherein the bus voltage setting unit reduces the bus voltage request value below the current bus voltage request value when the output power of the conversion circuit becomes equal to or greater than a predetermined power value that is smaller than the rated power, when the output voltage of the conversion circuit becomes equal to or greater than the rated voltage, or when the output current of the conversion circuit becomes equal to or greater than a predetermined current value that is smaller than the rated current of the conversion circuit.

3. 3. The power supply system according to claim 1, further comprising a current adjusting unit (16c) that reduces the output current of the conversion circuit below a current output current when the output power of the conversion circuit becomes equal to or greater than a predetermined power value smaller than the rated power, when the output voltage of the conversion circuit becomes equal to or greater than the rated voltage, or when the output current of the conversion circuit becomes equal to or greater than a predetermined current value smaller than the rated current of the conversion circuit.

4. The battery module is a first battery module (30), a second storage battery module (60) corresponding to the storage battery module; 4. The power supply system of claim 3, wherein when the output power of the conversion circuit of the first storage battery module becomes equal to or greater than the predetermined power value, when the output voltage of the conversion circuit of the first storage battery module becomes equal to or greater than the rated voltage, or when the output current of the conversion circuit of the first storage battery module becomes equal to or greater than the predetermined current value, the current adjustment unit reduces the output current of the conversion circuit of the first storage battery module below a current output current and increases the output current of the conversion circuit of the second storage battery module above a current output current.

5. The battery module is a first battery module (30), a second storage battery module (60) corresponding to the storage battery module; 3. The power supply system according to claim 1, wherein the control unit charges the storage battery of the first storage battery module from the storage battery of the second storage battery module when the output power of the conversion circuit of the first storage battery module becomes equal to or greater than a predetermined power value that is smaller than the rated power, when the output voltage of the conversion circuit of the first storage battery module becomes equal to or greater than the rated voltage, or when the output current of the conversion circuit of the first storage battery module becomes equal to or greater than a predetermined current value that is smaller than the rated current of the conversion circuit.

6. 3. The power supply system according to claim 1 or 2, further comprising a resistance adjustment unit (16d) that reduces an internal resistance of the storage battery of the storage battery module including the conversion circuit below a current internal resistance when the output power of the conversion circuit becomes equal to or greater than a predetermined power value that is smaller than the rated power, when the output voltage of the conversion circuit becomes equal to or greater than the rated voltage, or when the output current of the conversion circuit becomes equal to or greater than a predetermined current value that is smaller than the rated current of the conversion circuit.

7. The power supply system according to claim 6 , wherein the resistance adjustment unit changes the temperature of the storage battery from a current temperature to reduce the internal resistance of the storage battery below a current internal resistance.

8. 3. The power supply system according to claim 1, wherein a predetermined battery module (120) including a battery (121) and not including the conversion circuit is connected to the power supply bus.

9. A load (28) is connected to the battery module; 9. The power supply system according to claim 8, further comprising a disconnect circuit (22, 24, 25, 27) for disconnecting and connecting the battery module and the load to and from the power supply bus.

10. a load (28) connected to the power supply bus and to the given battery module; The power supply system according to claim 8, further comprising a disconnection circuit (120a, 120b) for disconnecting and connecting the predetermined battery module to the power supply bus and the load.

11. The power supply system according to claim 8, further comprising a switching circuit (22-27, 211-214) that switches the storage battery modules and the predetermined storage battery module between a parallel connection and a series connection.

12. A storage battery module (30, 60, 90) is provided, The power supply system according to claim 1 or 2, further comprising a switching circuit (22-27, 211-214) for switching the plurality of storage battery modules between parallel connection and series connection.

13. A control program applied to a power supply system (10, 210) in which a storage battery module (30, 60, 90) including a storage battery (31, 61, 91) and a conversion circuit (40, 70, 100) that converts power input from the storage battery to a primary side terminal pair (41, 42, 71, 72) and outputs the power from a secondary side terminal pair (47, 48, 77, 78) is connected to a power supply bus (11, 12), a positive electrode and a negative electrode of the storage battery are respectively connected to the primary side terminal pair of the conversion circuit, and the storage battery is connected in series to the secondary side terminal pair of the conversion circuit, setting a bus voltage requirement, which is a voltage required for the power supply bus; controlling an output voltage of the converter circuit so that an output voltage of the battery module approaches the bus voltage request value; setting the bus voltage requirement value such that an output power of the converter circuit is equal to or less than a rated power of the converter circuit or an output voltage of the converter circuit is equal to or less than a rated voltage of the converter circuit; A control program for causing a computer (16) to execute the above.

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