JP2020054082A - Control device of power supply system - Google Patents

Abstract

To make it possible to appropriately secure a cruising distance when a voltage converter fails in a power supply system including two or more power storage devices.SOLUTION: A power supply system includes: a first power storage device 10 connected to a driving motor 50; and a second power storage device 20 connected to the first power storage device 10 via a voltage converter 30. When the voltage converter 30 fails, the first power storage device 10 and the second power storage device 20 are electrically connected via the voltage converter 30. When the voltage converter 30 fails and when a difference between a voltage V1 of the first power storage device 10 and a voltage V2 of the second power storage device 20 is larger than a reference difference, a control device of the power supply system controls a current flowing from the power storage device connected to a load to the load connected to the first power storage device 10 or the second power storage device 20 so that a rate of decrease in the difference between the voltage of the first power storage device 10 and the voltage V2 of the second power storage device 20 increases.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a control device for a power supply system.

  In recent years, an electric vehicle such as an electric vehicle (EV) or a hybrid vehicle (HEV) equipped with a driving motor as a driving source has been known. The power supply system of the electric vehicle is provided with a power storage device that stores power supplied to the drive motor. Since the output and the capacity of the power storage device generally have a trade-off relationship, it may be difficult to achieve both the acceleration performance and the cruising distance of the vehicle with only one power storage device. Therefore, in order to achieve both the acceleration performance and the cruising distance of the vehicle, it has been proposed to use two power storage devices in combination, as disclosed in Patent Document 1, for example.

JP-A-2013-133859

  In a power supply system including two or more power storage devices, one power storage device is connected to a driving motor, and the one power storage device and another power storage device are connected to a voltage converter (specifically, a DCDC converter). It is possible to connect via. Thus, by controlling the operation of the voltage converter, power supply between the power storage devices can be controlled, and thus it is expected that power supply in the power supply system is appropriately controlled.

  Here, at the time of failure of the voltage converter, it becomes difficult to appropriately control the supply of power between the respective power storage devices. Therefore, the other power storage device and the other power storage device connected via the voltage converter are difficult to control. In some cases, it is difficult to use the power stored in the power storage device for driving the driving motor. As a result, the cruising distance may be reduced.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to appropriately secure a cruising distance when a voltage converter fails in a power supply system including two or more power storage devices. It is an object of the present invention to provide a new and improved power supply system control device capable of performing the above.

  According to an embodiment of the present invention, there is provided a first power storage device connected to a driving motor, and a second power storage device connected to the first power storage device via a voltage converter. Wherein the first power storage device and the second power storage device are electrically connected to each other via the voltage converter when the voltage converter fails. Has a control unit for controlling the supply of power in the power supply system, the control unit, when the voltage converter fails, the difference between the voltage of the first power storage device and the voltage of the second power storage device When the difference is larger than the reference difference, the current flowing from the power storage device connected to the load to the first power storage device or the load connected to the second power storage device is determined by the voltage of the first power storage device and the voltage of the second power storage device. The rate of decrease of the difference with the voltage increases Control, the control unit of the power supply system is provided.

  The first power storage device is connected to a first load including the drive motor, and the control unit is configured to control a voltage of the first power storage device and a voltage of the second power storage device when the voltage converter fails. Is larger than the reference difference and the voltage of the first power storage device is higher than the voltage of the second power storage device, the current flowing from the first power storage device to the first load is supplied to the voltage converter. It may be increased as compared with the time of non-failure.

  The control unit is configured to, when increasing a current flowing from the first power storage device to the first load as compared with a non-failure state of the voltage converter, a current flowing to the drive motor of the first load. Of the first load or an increase in the current flowing to a load other than the driving motor among the first loads may be determined according to a state of the power supply system.

  The second power storage device is connected to a second load, and when the voltage converter fails, the control unit determines that a difference between the voltage of the first power storage device and the voltage of the second power storage device is the reference. When the voltage is larger than the difference and the voltage of the first power storage device is higher than the voltage of the second power storage device, a current flowing from the second power storage device to the second load is compared with a non-failure state of the voltage converter. May be reduced.

  The second power storage device is connected to a second load, and when the voltage converter fails, the control unit determines that a difference between the voltage of the first power storage device and the voltage of the second power storage device is the reference. When the voltage is larger than the difference and the voltage of the second power storage device is higher than the voltage of the first power storage device, the current flowing from the second power storage device to the second load is compared with the non-failure state of the voltage converter. May be increased.

  The first power storage device is connected to a first load including the drive motor, and the control unit is configured to control a voltage of the first power storage device and a voltage of the second power storage device when the voltage converter fails. Is larger than the reference difference and the voltage of the second power storage device is higher than the voltage of the first power storage device, the current flowing from the first power storage device to the first load is converted to the voltage of the voltage converter. It may be reduced as compared with the time of non-failure.

  The control unit is configured to, when the voltage converter fails, when the difference between the voltage of the first power storage device and the voltage of the second power storage device is larger than the reference difference, the first power storage device or the second power storage device A current flowing from a power storage device connected to the load connected to the load may be controlled based on a current passing through the voltage converter.

  The control unit controls the operation of the voltage converter such that a difference between the voltage of the first power storage device and the voltage of the second power storage device is equal to or less than a first voltage difference when the voltage converter is not out of order. It may be controlled.

  The control unit may change the first voltage difference according to an index value having a correlation with a temperature of the driving motor.

  When stopping the power supply system, the control unit controls the operation of the voltage converter such that a difference between the voltage of the first power storage device and the voltage of the second power storage device is equal to or less than a second voltage difference. Later, the driving of the voltage converter may be stopped.

  As described above, according to the present invention, in a power supply system including two or more power storage devices, it is possible to appropriately secure a cruising distance when a voltage converter fails.

1 is a schematic diagram illustrating a schematic configuration of a power supply system including a control device according to an embodiment of the present invention. It is a block diagram showing an example of the functional composition of the control device concerning the embodiment. It is a flowchart which shows an example of the flow of the process regarding the power supply control at the time of failure of a DCDC converter among the processes which the control part which concerns on the embodiment performs. The flow of power in the power supply system when the first current adjustment control is performed when the voltage V1 of the first secondary battery is higher than the voltage V2 of the second secondary battery when the DCDC converter fails. FIG. The flow of power in the power supply system when the second current adjustment control is performed when the voltage V1 of the first secondary battery is higher than the voltage V2 of the second secondary battery when the DCDC converter fails. FIG. The flow of power in the power supply system when the third current adjustment control is performed when the voltage V2 of the second secondary battery is higher than the voltage V1 of the first secondary battery when the DCDC converter fails. FIG. The flow of power in the power supply system when the fourth current adjustment control is performed when the voltage V2 of the second secondary battery is higher than the voltage V1 of the first secondary battery at the time of failure of the DCDC converter is schematically illustrated. FIG. It is a flowchart which shows an example of the flow of the process regarding the power supply control at the time of a non-failure of a DCDC converter among the processes which the control part which concerns on the embodiment performs. It is a flowchart which shows an example of the flow of the process regarding the power supply control at the time of stopping a power supply system among the processes which the control part which concerns on the embodiment performs.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

<1. Configuration of power supply system>
First, a configuration of a power supply system 1 including a control device 100 according to an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic diagram illustrating a schematic configuration of the power supply system 1. FIG. 2 is a block diagram illustrating an example of a functional configuration of the control device 100.

  The power supply system 1 is, specifically, a system that is mounted on an electric vehicle such as an electric vehicle (EV) or a hybrid vehicle (HEV) and is used to supply power to each device in the vehicle. The electric vehicle may be any vehicle provided with a drive motor as a drive source, and includes a railway vehicle.

  As shown in FIG. 1, the power supply system 1 includes a first secondary battery 10, a second secondary battery 20, and a control device 100. Further, the power supply system 1 includes a DCDC converter 30, an inverter 40, a driving motor 50, a first battery sensor 71, a second battery sensor 72, an outside air temperature sensor 73, and a converter current sensor 74. The vehicle in which the power supply system 1 is mounted runs using the drive motor 50 as a drive source.

  In the power supply system 1, the first secondary battery 10 corresponds to an example of a first power storage device according to the present invention. The second secondary battery 20 corresponds to an example of a second power storage device according to the present invention. The DCDC converter 30 corresponds to an example of the voltage converter according to the present invention.

  Further, in the power supply system 1, as described later, when the DCDC converter 30 fails, the first secondary battery 10 and the second secondary battery 20 are electrically connected via the DCDC converter 30. .

  The first secondary battery 10 is a power storage device connected to the driving motor 50. Specifically, the first secondary battery 10 is connected to the driving motor 50 via the inverter 40. As the first secondary battery 10, for example, a secondary battery such as a lithium ion battery is used. The first secondary battery 10 is not particularly limited to such an example, and may be another secondary battery such as a nickel-metal hydride battery, or another power storage device such as an electric double layer capacitor. Good. Further, from the viewpoint of effectively improving the acceleration performance of the vehicle, the first secondary battery 10 is a power storage device having a higher output (that is, having a higher output density) than the second secondary battery 20. Is preferred.

  The drive motor 50 can output power for driving the drive wheels of the vehicle, and is specifically a multi-phase AC (for example, three-phase AC) motor. The driving motor 50 generates power using electric power supplied from the first secondary battery 10 via the inverter 40. Further, the drive motor 50 may have a function as a generator (regeneration function) that generates electric power by using the rotational energy of the drive wheels when the vehicle decelerates.

  Inverter 40 is a power converter that can bidirectionally convert power between DC and AC, and specifically includes a polyphase bridge circuit. The inverter 40 can convert DC power supplied from the first secondary battery 10 into AC power and supply the AC power to the driving motor 50. Further, the inverter 40 can convert AC power regenerated by the drive motor 50 into DC power and supply the DC power to the first secondary battery 10. The inverter 40 is provided with a switching element, and by controlling the operation of the switching element, the supply of electric power between the first secondary battery 10 and the driving motor 50 is controlled.

  The second secondary battery 20 is a power storage device connected to the first secondary battery 10 via the DCDC converter 30. As the second secondary battery 20, for example, a secondary battery such as a lithium ion battery is used. The second secondary battery 20 is not particularly limited to such an example, and may be another secondary battery such as a nickel-metal hydride battery, or another power storage device such as an electric double layer capacitor. Good. Further, from the viewpoint of effectively increasing the cruising distance of the vehicle, the second secondary battery 20 is a power storage device having a higher capacity (that is, having a larger energy density) than the first secondary battery 10. Is preferred.

  The DCDC converter 30 is a voltage converter capable of bidirectionally performing voltage conversion, and includes, for example, a chopper circuit. The DCDC converter 30 can supply power stored in the first secondary battery 10 to the second secondary battery 20 by appropriately performing voltage conversion. The DCDC converter 30 can supply the power stored in the second secondary battery 20 to the first secondary battery 10 by appropriately performing voltage conversion. The DCDC converter 30 is provided with a switching element, and by controlling the operation of the switching element, power supply between the first secondary battery 10 and the second secondary battery 20 is controlled.

  Here, when the DCDC converter 30 fails (specifically, it becomes difficult to normally control the operation of the switching element of the DCDC converter 30 due to heat input or vibration input to the DCDC converter 30). At that time, the switching element of the DCDC converter 30 is in a closed state (that is, a state in which current flows). Thus, the DCDC converter 30 is a so-called normally closed type. Specifically, as the switching element of the DCDC converter 30, an element that is in a closed state when power is not supplied is used. When the DCDC converter 30 fails, power cannot be supplied to each switching element for controlling the operation of the switching element (that is, the power is not supplied), and each switching element is closed. Therefore, when the DCDC converter 30 fails, the first secondary battery 10 and the second secondary battery 20 are electrically connected via the DCDC converter 30.

  The above-described first secondary battery 10 is connected to a first load 61 including a driving motor 50. That is, the first load 61 is a load in the vehicle connected to the first secondary battery 10. For example, the loads other than the drive motor 50 in the first load 61 include a heater used for a heating device, a heater for increasing the temperature of each battery (for example, a PTC (Positive Temperature Coefficient) heater), and a refrigerant for a cooling device. It includes a pump or a pump for cooling a battery for cooling each battery. The load other than the drive motor 50 in the first load 61 may be any device in the vehicle that can consume the supplied power. For example, a converter that steps down the power supplied from the first secondary battery 10 Or, it may include a device to which the power stepped down by the converter is supplied.

  Further, the above-described second secondary battery 20 is connected to the second load 62. That is, the second load 62 is a load in the vehicle connected to the second secondary battery 20. For example, the second load 62 includes a heater used for a heating device, a heater (for example, a PTC heater) for raising the temperature of each battery, a pump for cooling a cooling device, or a pump for cooling each battery. And so on. The second load 62 may be any device in the vehicle that can consume the supplied power. For example, the second load 62 may be a converter that steps down the power supplied from the second secondary battery 20 or the power stepped down by the converter. May be provided.

  The first battery sensor 71 detects various state quantities of the first secondary battery 10 and outputs them to the control device 100. Specifically, the first battery sensor 71 detects the voltage V1 of the first secondary battery 10 (for example, the open-end voltage of the first secondary battery 10) as the state quantity of the first secondary battery 10. Note that the first battery sensor 71 may detect, for example, the remaining capacity or the temperature of the first secondary battery 10 as a state quantity other than the voltage V1.

  The second battery sensor 72 detects various state quantities of the second secondary battery 20 and outputs them to the control device 100. Specifically, the second battery sensor 72 detects the voltage V2 of the second secondary battery 20 (for example, the open-end voltage of the second secondary battery 20) as the state quantity of the second secondary battery 20. Note that the second battery sensor 72 may detect, for example, the remaining capacity or the temperature of the second secondary battery 20 as a state quantity other than the voltage V2.

  The outside air temperature sensor 73 detects an outside air temperature that is the outside temperature of the vehicle, and outputs the detected outside air temperature to the control device 100.

  Converter current sensor 74 detects a current passing through DCDC converter 30 and outputs the current to control device 100.

  The control device 100 includes a CPU (Central Processing Unit) that is an arithmetic processing device, a ROM (Read Only Memory) that is a storage element that stores a program used by the CPU, an arithmetic parameter, and the like, and a parameter that appropriately changes in execution of the CPU. It is composed of a RAM (Random Access Memory), which is a storage element for temporarily storing, and the like.

  The control device 100 communicates with each device mounted on the power supply system 1. Communication between the control device 100 and each device is realized using, for example, CAN (Controller Area Network) communication.

  Note that the functions of the control device 100 according to the present embodiment may be at least partially divided by a plurality of control devices, and the plurality of functions may be realized by one control device. When the functions of the control device 100 are at least partially divided by a plurality of control devices, the plurality of control devices may be connected to each other via a communication bus such as a CAN.

  The control device 100 includes, for example, an acquisition unit 110 and a control unit 120, as illustrated in FIG.

  The acquisition unit 110 acquires various information used in the processing performed by the control unit 120, and outputs the acquired information to the control unit 120. For example, the acquiring unit 110 communicates with the first battery sensor 71, the second battery sensor 72, the outside temperature sensor 73, and the converter current sensor 74 to acquire various information output from these sensors.

  The control unit 120 controls power supply in the power supply system 1. For example, the control unit 120 includes a converter control unit 121, a first load control unit 122, and a second load control unit 123.

  The converter control unit 121 controls the operation of the DCDC converter 30 (specifically, the operation of the switching element of the DCDC converter 30) to allow the first secondary battery 10 and the second secondary battery 20 to switch between them. Control the power supply. Specifically, converter control unit 121 causes power stored in first secondary battery 10 to be supplied to second secondary battery 20 or converts power stored in second secondary battery 20 to first secondary battery 20. It can be supplied to the battery 10.

  Here, when the DCDC converter 30 fails, it becomes difficult for the converter control unit 121 to normally control the operation of the switching element of the DCDC converter 30 as described above. As a result, the first secondary battery 10 and the second secondary battery 20 are electrically connected via the DCDC converter 30.

  The first load control unit 122 controls supply of power from the first secondary battery 10 to the first load 61. Specifically, the first load control unit 122 controls the operation of a switch or the like that can adjust the power supplied to the first load 61, and thereby controls the power stored in the first secondary battery 10 to the first power. It can be supplied to the load 61.

  For example, the first load control unit 122 controls the operation of the inverter 40 (specifically, the operation of the switching element of the inverter 40) so that the first load control unit 122 connects between the first secondary battery 10 and the driving motor 50. Control the power supply. Specifically, the first load control unit 122 causes the power stored in the first secondary battery 10 to be supplied to the drive motor 50, or the regenerative power generated by the drive motor 50 to the first secondary battery 10. 10 can be supplied. Thereby, the first load control unit 122 can control generation of power and power generation by the driving motor 50. For example, the first load control unit 122 controls the output of the drive motor 50 according to the running state of the vehicle such as an acceleration request and a vehicle speed.

  The second load control unit 123 controls supply of power from the second secondary battery 20 to the second load 62. Specifically, the second load control unit 123 controls the operation of a switch or the like (not shown) that can adjust the power supplied to the second load 62, and thereby controls the power stored in the second secondary battery 20. It can be supplied to the second load 62.

  As described above, in the power supply system 1, when the DCDC converter 30 fails, the first secondary battery 10 and the second secondary battery 20 are electrically connected via the DCDC converter 30. Thus, even when the DCDC converter 30 fails, the electric power stored in the second secondary battery 20 can be used for driving the driving motor 50. However, when the DCDC converter 30 fails, the first secondary battery 10 and the second secondary battery 20 are electrically connected via the DCDC converter 30, so that the voltage V1 of the first secondary battery 10 and the second A current corresponding to the difference from the voltage V2 of the secondary battery 20 flows through the DCDC converter 30. As a result, there is a possibility that the DCDC converter 30 is disconnected due to burnout.

  Here, in the control device 100 of the power supply system 1, when the DCDC converter 30 fails, the control unit 120 determines that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is smaller than the reference difference. If it is larger, the current flowing from the secondary battery connected to the load to the load connected to the first secondary battery 10 or the second secondary battery 20 is equal to the voltage V1 of the first secondary battery 10 and the second secondary battery. Control is performed so that the rate of decrease in the difference between the voltage V2 of the battery 20 and the voltage V2 increases (that is, the difference between the voltage V1 and the voltage V2 decreases more quickly). Here, the reference difference appropriately determines whether or not the DCDC converter 30 is relatively likely to be disconnected due to burnout due to a current corresponding to the difference between the voltage V1 and the voltage V2 passing through the DCDC converter 30. Is set to a value that can be determined. By performing the above-described control when the DCDC converter 30 fails, the cruising distance can be appropriately secured when the DCDC converter 30 fails. The details of the processing related to the control of the power supply (hereinafter, also referred to as power supply control) performed by the control unit 120 will be described later.

<2. Operation of control device>
Subsequently, an operation of the control device 100 according to the embodiment of the present invention will be described with reference to FIGS.

[2-1. Power supply control in case of failure of DCDC converter]
First, with reference to FIGS. 3 to 7, power supply control performed by the control unit 120 when the DCDC converter 30 fails will be described.

  FIG. 3 is a flowchart illustrating an example of a flow of processing related to power supply control when the DCDC converter 30 fails, among the processing performed by the control unit 120. The control flow shown in FIG. 3 is specifically executed when the DCDC converter 30 is not out of order.

  When the control flow illustrated in FIG. 3 is started, first, in step S501, the control unit 120 determines whether the DCDC converter 30 has failed. When it is determined that the DCDC converter 30 has failed (step S501 / YES), the process proceeds to step S503. On the other hand, when it is not determined that the DCDC converter 30 has failed (step S501 / NO), the determination process of step S501 is repeated.

  For example, the control unit 120 determines whether or not the DCDC converter 30 has failed based on the detection result of the current passing through the DCDC converter 30 by the converter current sensor 74. As described above, when the DCDC converter 30 is not out of order, the operation of the switching element of the DCDC converter 30 is controlled normally. On the other hand, when the DCDC converter 30 fails, it becomes difficult to normally control the operation of the switching elements of the DCDC converter 30, and each switching element is closed. As a result, the first secondary battery 10 and the second secondary battery 20 are electrically connected via the DCDC converter 30. Therefore, the behavior of the current passing through the DCDC converter 30 changes depending on whether the DCDC converter 30 has failed. Therefore, control unit 120 can determine whether or not DCDC converter 30 has failed, for example, based on the transition of the detected value of the current passing through DCDC converter 30.

  The control unit 120 calculates the current passing through the DCDC converter 30 based on the detection result of the current input / output to / from the first secondary battery 10 and the current input / output to / from the second secondary battery 20. It may be determined whether or not the DCDC converter 30 has failed based on the obtained calculation result. In this case, the current input to and output from the first secondary battery 10 and the current input to and output from the second secondary battery 20 can be detected by, for example, the first battery sensor 71 and the second battery sensor 72, respectively.

  If YES is determined in step S501, in step S503, the control unit 120 determines whether the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is larger than the reference difference. judge. When it is determined that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is larger than the reference difference (step S503 / YES), the process proceeds to step S505. On the other hand, if it is not determined that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is larger than the reference difference (step S503 / NO), the control flow shown in FIG. finish.

  When YES is determined in step S503, in step S505, the control unit 120 performs a current adjustment control that is a control for adjusting a current flowing from the secondary battery to a load connected to the secondary battery. Specifically, in the current adjustment control, the control unit 120 outputs the current flowing from the secondary battery connected to the load to the load connected to the first secondary battery 10 or the second secondary battery 20 to the first secondary battery 10 or the first secondary battery 20. Control is performed such that the rate of decrease in the difference between the voltage V1 of the secondary battery 10 and the voltage V2 of the second secondary battery 20 increases.

  Hereinafter, as examples of the current adjustment control performed by the control unit 120, a first current adjustment control, a second current adjustment control, a third current adjustment control, and a fourth current adjustment control will be described with reference to FIGS. This will be described with reference to FIGS. Note that the first current adjustment control and the second current adjustment control are current adjustment controls that are performed when the voltage V1 of the first secondary battery 10 is higher than the voltage V2 of the second secondary battery 20. The current adjustment control and the fourth current adjustment control are current adjustment controls performed when the voltage V2 of the second secondary battery 20 is higher than the voltage V1 of the first secondary battery 10.

  The first current adjustment control is performed when the voltage V1 of the first secondary battery 10 is higher than the voltage V2 of the second secondary battery 20, as described above. In the first current adjustment control, the first load control unit 122 of the control unit 120 increases the current flowing from the first secondary battery 10 to the first load 61 (for example, the driving motor 50). As described above, when the DCDC converter 30 fails, the control unit 120 determines that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is larger than the reference difference, and When the voltage V1 of the battery 10 is higher than the voltage V2 of the second secondary battery 20, the current flowing from the first secondary battery 10 to the first load 61 may be increased as compared to when the DCDC converter 30 is not in failure. .

  FIG. 4 shows the power supply system 1 when the first current adjustment control is performed when the voltage V1 of the first secondary battery 10 is higher than the voltage V2 of the second secondary battery 20 when the DCDC converter 30 fails. FIG. 4 is a diagram schematically showing a flow of electric power of FIG. In FIG. 4 and FIGS. 5 to 7 which will be referred to later, the flow of power in the power supply system 1 is schematically indicated by arrows.

  As described above, when the DCDC converter 30 fails, each switching element of the DCDC converter 30 is closed, and the first secondary battery 10 and the second secondary battery 20 are electrically connected via the DCDC converter 30. . In FIG. 4 and FIGS. 5 to 7 which will be referred to later, the state where the switching element of the DCDC converter 30 is in the closed state is conceptually indicated by a broken line. In detail, as described above, the electric circuit of the DCDC converter 30 is, for example, a chopper circuit, and the electric circuit includes a plurality of switching elements.

  When the DCDC converter 30 fails and the first secondary battery 10 and the second secondary battery 20 are electrically connected via the DCDC converter 30, the voltage V1 of the first secondary battery 10 is changed to the second secondary battery. When the voltage is higher than the voltage V2 of the battery 20, a current corresponding to the difference between the voltage V1 and the voltage V2 is supplied from the first secondary battery 10 to the second secondary battery 20 via the DCDC converter 30, as shown in FIG. Flows.

  Here, in the first current adjustment control, the first load control unit 122 increases, for example, the current flowing from the first secondary battery 10 to the driving motor 50 as compared with the time when the DCDC converter 30 does not fail. In FIG. 4, the magnitudes of the current flowing from the first secondary battery 10 to the drive motor 50 before and after the increase are conceptually indicated by the thicknesses of the dashed arrow and the solid arrow, respectively. As described above, by increasing the current flowing from the first secondary battery 10 to the drive motor 50 as compared with the non-failure state of the DCDC converter 30, to promote the reduction of the voltage V1 of the first secondary battery 10. Can be. Therefore, the rate of decrease in the difference between the voltage V1 of the first rechargeable battery 10 and the voltage V2 of the second rechargeable battery 20 can be appropriately increased, so that the first rechargeable battery 10 to the second rechargeable battery 20 The current passing through the DC-DC converter 30 in the direction toward can be rapidly reduced. Therefore, disconnection of the DCDC converter 30 due to burnout when the DCDC converter 30 fails can be appropriately suppressed.

  Note that, when a request for driving the driving motor 50 does not occur when the DCDC converter 30 fails (for example, when the accelerator operation is not performed), the first load control unit 122 outputs The power stored in the first secondary battery 10 is supplied to the driving motor 50 regardless of whether or not there is a request to drive the motor 50. Thereby, the current passing through the DCDC converter 30 in the direction from the first secondary battery 10 to the second secondary battery 20 can be quickly reduced.

  More specifically, in the first current adjustment control, the first load control unit 122 increases the current flowing from the first secondary battery 10 to the driving motor 50 as compared with the time when the DCDC converter 30 does not fail. The output of the driving motor 50 is controlled so that the output of the driving motor 50 does not increase due to the reason. Specifically, the first load control unit 122 controls the output of the drive motor 50 to be an output corresponding to the accelerator operation amount by appropriately controlling the operation of the inverter 40. When there is no request to drive the drive motor 50, the first load control unit 122 performs so-called zero torque control so that the output torque of the drive motor 50 becomes zero.

  The first load 61 may include a load in the vehicle other than the driving motor 50, as described above. Therefore, in the first current adjustment control, the first load control unit 122 increases the current flowing from the first secondary battery 10 to a load other than the drive motor 50 as compared with the time when the DCDC converter 30 does not fail. Is also good.

  Here, a large current can generally flow through the driving motor 50 as compared with other loads. Therefore, in the first current adjustment control, when the current flowing from the first secondary battery 10 to the drive motor 50 is increased, the voltage V1 of the first secondary battery 10 and the voltage V2 of the second Since the rate of decrease of the difference can be more effectively increased, even if the difference between the voltage V1 and the voltage V2 when the failure of the DCDC converter 30 occurs is relatively large, the DCDC converter 30 may be burned out. Disconnection can be appropriately suppressed.

  On the other hand, in the first current adjustment control, when increasing the current flowing from the first secondary battery 10 to a load other than the drive motor 50, the voltage V1 and the voltage V2 are controlled while suppressing the increase in the current flowing to the drive motor 50. Since the rate of decrease of the difference with the drive motor 50 can be increased, breakage and deterioration of the drive motor 50 (for example, deterioration of the magnet in the drive motor 50) can be suppressed.

  In the first current adjustment control, from the viewpoint of achieving the above advantages in both the case where the current flowing through the driving motor 50 is increased and the case where the current flowing through a load other than the driving motor 50 is increased, the first load control is performed. The unit 122 determines which of the increase in the current flowing to the drive motor 50 of the first load 61 and the increase in the current flowing to the load other than the drive motor 50 of the first load 61 is prioritized. It is preferable to determine according to the state of the power supply system 1.

  It should be noted that to prioritize an increase in one of the current flowing through the driving motor 50 and the current flowing through a load other than the driving motor 50 means that an increase in one current is performed before an increase in the other current. Or that the amount of increase in one current is greater than the amount of increase in the other current. The state of the power supply system 1 includes, for example, the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20, the temperature of the driving motor 50, or the driving state of the first load 61. The temperature of a load other than the motor 50 is included.

  For example, as the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 increases, the first load control unit 122 gives priority to increasing the current flowing through the drive motor 50, and The smaller the difference between the voltage V1 of the secondary battery 10 and the voltage V2 of the second secondary battery 20, the higher the priority is given to the increase in the current flowing to loads other than the driving motor 50. Thereby, it is possible to achieve both suppression of disconnection due to burning of the DCDC converter 30 and suppression of breakage and deterioration of the driving motor 50.

  Further, for example, the first load control unit 122 gives priority to an increase in the current flowing through the drive motor 50 as the temperature of the drive motor 50 is lower, and the load other than the drive motor 50 as the temperature of the drive motor 50 is higher. Priority is given to increasing the current flowing through Here, the upper limit of the power that can be consumed by the drive motor 50 changes according to the temperature of the drive motor 50. Specifically, the higher the temperature of the driving motor 50, the lower the upper limit of the power that can be consumed by the driving motor 50. Therefore, as described above, whether to prioritize the increase in the current flowing through the driving motor 50 or the increase in the current flowing through the load other than the driving motor 50 is determined, and thus the disconnection due to the burnout of the DCDC converter 30 is determined. And the suppression of breakage and deterioration of the driving motor 50 can be achieved at the same time.

  For example, when a PTC heater is used as a load other than the drive motor 50, the first load control unit 122 gives priority to an increase in the current flowing through the drive motor 50 as the temperature of the PTC heater increases, and As the temperature is lower, priority is given to increasing the current flowing through the PTC heater. Here, the lower the temperature of the PTC heater, the lower the electrical resistance of the PTC heater, and the easier it is to flow current to the PTC heater. Therefore, as described above, whether to prioritize the increase in the current flowing through the driving motor 50 or the increase in the current flowing through the load other than the driving motor 50 is determined, and thus the disconnection due to the burnout of the DCDC converter 30 is determined. And the suppression of breakage and deterioration of the driving motor 50 can be achieved at the same time.

  Here, when the current flowing from the first secondary battery 10 to the first load 61 is increased as compared with the non-failure state of the DCDC converter 30, the larger the amount of increase of the current is, the more the voltage of the first secondary battery 10 is increased. Since the effect of promoting the reduction of V1 can be improved, the rate of decrease in the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 can be effectively increased. In addition, as the current passing through the DCDC converter 30 increases, the necessity of increasing the rate of decrease in the difference between the voltage V1 and the voltage V2 greatly increases. Therefore, from the viewpoint of more appropriately suppressing disconnection of the DCDC converter 30 due to burnout, in the first current adjustment control, the first load control unit 122 performs the first secondary control based on the current passing through the DCDC converter 30. It is preferable to control the current flowing from the battery 10 to the first load 61.

  Note that the first load control unit 122 may use the value detected by the converter current sensor 74 as the value of the current passing through the DCDC converter 30, and the current input to and output from the first secondary battery 10 and the second A value obtained by calculating based on the detection result of the current input to and output from the secondary battery 20 may be used.

  As described above, the second current adjustment control is performed when the voltage V1 of the first secondary battery 10 is higher than the voltage V2 of the second secondary battery 20, as in the first current adjustment control. In the second current adjustment control, the second load control unit 123 of the control unit 120 reduces the current flowing from the second secondary battery 20 to the second load 62. As described above, when the DCDC converter 30 fails, the control unit 120 determines that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is larger than the reference difference, and When the voltage V1 of the battery 10 is higher than the voltage V2 of the second secondary battery 20, the current flowing from the second secondary battery 20 to the second load 62 may be reduced as compared to when the DCDC converter 30 is not in failure. .

  FIG. 5 shows the power supply system 1 when the second current adjustment control is performed when the voltage V1 of the first secondary battery 10 is higher than the voltage V2 of the second secondary battery 20 when the DCDC converter 30 fails. FIG. 4 is a diagram schematically showing a flow of electric power of FIG.

  When the DCDC converter 30 fails and the first secondary battery 10 and the second secondary battery 20 are electrically connected via the DCDC converter 30, the voltage V1 of the first secondary battery 10 is changed to the second secondary battery. When the voltage is higher than the voltage V2 of the battery 20, a current corresponding to the difference between the voltage V1 and the voltage V2 is supplied from the first secondary battery 10 to the second secondary battery 20 as shown in FIG. It flows through converter 30.

  Here, in the second current adjustment control, the second load control unit 123 reduces the current flowing from the second secondary battery 20 to the second load 62 as compared with the time when the DCDC converter 30 is not out of order. In FIG. 5, the magnitudes of the current flowing from the second secondary battery 20 to the second load 62 before and after the increase are conceptually indicated by the thicknesses of the dashed arrow and the solid arrow, respectively. As described above, the current flowing from the second secondary battery 20 to the second load 62 is reduced as compared with the non-failure state of the DCDC converter 30, so that the decrease in the voltage V2 of the second secondary battery 20 is suppressed. Can be. Therefore, the rate of decrease in the difference between the voltage V1 of the first rechargeable battery 10 and the voltage V2 of the second rechargeable battery 20 can be appropriately increased, so that the first rechargeable battery 10 to the second rechargeable battery 20 The current passing through the DC-DC converter 30 in the direction toward can be rapidly reduced. Therefore, disconnection of the DCDC converter 30 due to burnout when the DCDC converter 30 fails can be appropriately suppressed.

  The second load 62 may include various loads in the vehicle as described above. That is, in the second current adjustment control, the second load 62 that is a target for reducing the current sent from the second secondary battery 20 can be appropriately selected from a plurality of loads in the vehicle. For example, from the viewpoint of quickly reducing the current flowing from the second secondary battery 20 to the second load 62, the second current adjustment control is to reduce the current sent from the second secondary battery 20 in the second current adjustment control. As the load 62, a load (for example, a heater) that easily increases power consumption is preferably used.

  Here, as the amount of decrease in the current flowing from the second secondary battery 20 to the second load 62 in comparison with the non-failure state of the DCDC converter 30 increases, the voltage of the second secondary battery 20 increases. Since the effect of suppressing the decrease in V2 can be improved, the rate of decrease in the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 can be effectively increased. Further, as described above, as the current passing through the DCDC converter 30 increases, the necessity of increasing the rate of decrease in the difference between the voltage V1 and the voltage V2 greatly increases. Therefore, from the viewpoint of more appropriately suppressing disconnection of the DCDC converter 30 due to burnout, in the second current adjustment control, the second load control unit 123 performs the second secondary control based on the current passing through the DCDC converter 30. It is preferable to control the current flowing from the battery 20 to the second load 62.

  Note that, like the first load control unit 122, the second load control unit 123 may use the value detected by the converter current sensor 74 as the value of the current passing through the DCDC converter 30. A value obtained by calculating based on the detection result of the current input / output to and the current input / output to / from the second secondary battery 20 may be used.

  As described above, the third current adjustment control is performed when the voltage V2 of the second secondary battery 20 is higher than the voltage V1 of the first secondary battery 10. In the third current adjustment control, the second load control unit 123 of the control unit 120 increases the current flowing from the second secondary battery 20 to the second load 62. As described above, when the DCDC converter 30 fails, the control unit 120 determines that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is larger than the reference difference, and When the voltage V2 of the battery 20 is higher than the voltage V1 of the first secondary battery 10, the current flowing from the second secondary battery 20 to the second load 62 may be increased as compared to when the DCDC converter 30 is not in failure. .

  FIG. 6 shows the power supply system 1 when the third current adjustment control is performed when the voltage V2 of the second secondary battery 20 is higher than the voltage V1 of the first secondary battery 10 when the DCDC converter 30 fails. FIG. 4 is a diagram schematically showing a flow of electric power of FIG.

  When the DCDC converter 30 fails and the first secondary battery 10 and the second secondary battery 20 are electrically connected via the DCDC converter 30, the voltage V2 of the second secondary battery 20 is changed to the first secondary battery. When the voltage is higher than the voltage V1 of the battery 10, as shown in FIG. 6, a current corresponding to a difference between the voltage V1 and the voltage V2 is transferred from the second secondary battery 20 to the first secondary battery 10 via the DCDC converter 30. Flows.

  Here, in the third current adjustment control, the second load control unit 123 increases the current flowing from the second secondary battery 20 to the second load 62 as compared to when the DCDC converter 30 is not in failure. In FIG. 6, the magnitudes before and after the increase in the current flowing from the second secondary battery 20 to the second load 62 are conceptually indicated by the thickness of the dashed arrow and the solid arrow, respectively. As described above, the current flowing from the second secondary battery 20 to the second load 62 is increased as compared with the non-failure state of the DCDC converter 30, thereby promoting the reduction of the voltage V2 of the second secondary battery 20. Can be. Therefore, the rate of decrease in the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 can be appropriately increased, so that the first secondary battery 10 The current passing through the DC-DC converter 30 in the direction toward can be rapidly reduced. Therefore, disconnection of the DCDC converter 30 due to burnout when the DCDC converter 30 fails can be appropriately suppressed.

  If there is no request to supply power to the second load 62 when the DCDC converter 30 fails, the second load control unit 123 determines whether there is a request to supply power to the second load 62. Regardless, the power stored in the second secondary battery 20 is supplied to the second load 62. Thereby, the current passing through the DCDC converter 30 in the direction from the second secondary battery 20 to the first secondary battery 10 can be quickly reduced.

  The second load 62 may include various loads in the vehicle as described above. Therefore, in the third current adjustment control, the second load 62, which is a target for increasing the current sent from the second secondary battery 20 when the DCDC converter 30 fails, is provided inside the vehicle similarly to the second current adjustment control. Can be appropriately selected from among a plurality of loads.

  Here, when the current flowing from the second secondary battery 20 to the second load 62 is increased as compared with the non-failure state of the DCDC converter 30, the voltage of the second secondary battery 20 increases as the current increases. Since the effect of promoting the reduction of V2 can be improved, the rate of decrease in the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 can be effectively increased. Further, as described above, as the current passing through the DCDC converter 30 increases, the necessity of increasing the rate of decrease in the difference between the voltage V1 and the voltage V2 greatly increases. Therefore, from the viewpoint of more appropriately suppressing disconnection of the DCDC converter 30 due to burnout, in the third current adjustment control, the second load control unit 123 performs the second secondary control based on the current passing through the DCDC converter 30. It is preferable to control the current flowing from the battery 20 to the second load 62.

  As described above, the fourth current adjustment control is performed when the voltage V2 of the second secondary battery 20 is higher than the voltage V1 of the first secondary battery 10, as in the third current adjustment control. In the fourth current adjustment control, the first load control unit 122 of the control unit 120 reduces the current flowing from the first secondary battery 10 to the first load 61 (for example, the driving motor 50). As described above, when the DCDC converter 30 fails, the control unit 120 determines that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is larger than the reference difference, and When the voltage V2 of the battery 20 is higher than the voltage V1 of the first secondary battery 10, the current flowing from the first secondary battery 10 to the first load 61 may be reduced as compared with the non-failure state of the DCDC converter 30. .

  FIG. 7 shows the power supply system 1 when the fourth current adjustment control is performed when the voltage V2 of the second secondary battery 20 is higher than the voltage V1 of the first secondary battery 10 when the DCDC converter 30 fails. FIG. 4 is a diagram schematically showing a flow of electric power of FIG.

  When the DCDC converter 30 fails and the first secondary battery 10 and the second secondary battery 20 are electrically connected via the DCDC converter 30, the voltage V2 of the second secondary battery 20 is changed to the first secondary battery. When the voltage is higher than the voltage V1 of the battery 10, a current corresponding to the difference between the voltage V1 and the voltage V2 is applied from the second secondary battery 20 to the first secondary battery 10 as shown in FIG. It flows through converter 30.

  Here, in the fourth current adjustment control, the first load control unit 122 reduces, for example, the current flowing from the first secondary battery 10 to the drive motor 50 as compared with the time when the DCDC converter 30 is not out of order. In FIG. 7, the magnitude of the current flowing from the first secondary battery 10 to the drive motor 50 before and after the increase is conceptually indicated by the thickness of the dashed arrow and the solid arrow, respectively. As described above, by reducing the current flowing from the first secondary battery 10 to the drive motor 50 as compared with the time when the DCDC converter 30 is not out of order, it is possible to suppress a decrease in the voltage V1 of the first secondary battery 10. Can be. Therefore, the rate of decrease in the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 can be appropriately increased, so that the first secondary battery 10 The current passing through the DC-DC converter 30 in the direction toward can be rapidly reduced. Therefore, disconnection of the DCDC converter 30 due to burnout when the DCDC converter 30 fails can be appropriately suppressed.

  More specifically, in the fourth current adjustment control, the first load control unit 122 reduces the current flowing from the first secondary battery 10 to the drive motor 50 as compared with the time when the DCDC converter 30 is not in failure. As in the first current adjustment control, the output of the drive motor 50 is controlled so that the output of the drive motor 50 does not decrease due to this.

  The first load 61 may include a load in the vehicle other than the driving motor 50, as described above. Therefore, in the fourth current adjustment control, the first load control unit 122 converts the current flowing from the first secondary battery 10 to a load other than the drive motor 50 into the DCDC converter 30 in the same manner as the first current adjustment control. It may be reduced as compared with the time of non-failure.

  Here, when the amount of decrease in the current flowing from the first secondary battery 10 to the first load 61 as compared with the non-failure state of the DCDC converter 30 is greater, the voltage of the first secondary battery 10 is larger. Since the effect of suppressing the decrease in V1 can be improved, the rate of decrease in the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 can be effectively increased. Further, as described above, as the current passing through the DCDC converter 30 increases, the necessity of increasing the rate of decrease in the difference between the voltage V1 and the voltage V2 greatly increases. Therefore, from the viewpoint of more appropriately suppressing disconnection of the DCDC converter 30 due to burnout, in the fourth current adjustment control, the first load control unit 122 performs the first secondary control based on the current passing through the DCDC converter 30. It is preferable to control the current flowing from the battery 10 to the first load 61.

  After step S505, the control flow illustrated in FIG. 3 ends.

[2-2. Power supply control at the time of non-failure of DCDC converter]
Next, the power supply control performed by the control unit 120 when the DCDC converter 30 does not fail will be described with reference to FIG.

  As described above, according to the power supply control performed by the control unit 120 when the DCDC converter 30 fails, when the DCDC converter 30 fails, the voltage V1 of the first secondary battery 10 and the voltage of the second secondary battery 20 When the difference from V2 is larger than the reference difference, the current flowing from the secondary battery connected to the load to the load connected to the first secondary battery 10 or the second secondary battery 20 is changed to the first secondary battery 10 By controlling the rate of decrease of the difference between the voltage V1 of the second secondary battery 20 and the voltage V2 of the second secondary battery 20 to increase, it is possible to prevent the DCDC converter 30 from being disconnected due to burnout. Here, since there is an upper limit value of the power that can be consumed by the load connected to the secondary battery, there is an upper limit value of the current that can flow through the load connected to the secondary battery. Therefore, if the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is excessively large when the failure of the DCDC converter 30 occurs, the current passing through the DCDC converter 30 becomes excessive. Therefore, it may be difficult to sufficiently increase the speed of decreasing the difference between the voltage V1 and the voltage V2 in the above-described power supply control when the DCDC converter 30 fails.

  Therefore, from the viewpoint of more appropriately preventing the DCDC converter 30 from being broken due to burnout when the DCDC converter 30 fails, the voltage V1 of the first secondary battery 10 and the second secondary battery 10 when the DCDC converter 30 fails. It is preferable to perform processing for suppressing the difference from the voltage V2 of the battery 20 from becoming excessively large. As such processing, specifically, when the DCDC converter 30 does not fail, the control unit 120 determines that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is the first voltage. The operation of the DCDC converter 30 is controlled so that the difference is equal to or less than the difference. Hereinafter, the above processing performed by the control unit 120 will be described in detail with reference to FIG.

  FIG. 8 is a flowchart illustrating an example of a flow of processing related to power supply control when the DCDC converter 30 is not out of order among the processing performed by the control unit 120. Specifically, the control flow shown in FIG. 8 is repeatedly executed when the DCDC converter 30 is not out of order.

  When the control flow illustrated in FIG. 8 is started, first, in step S601, the control unit 120 determines that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is the first voltage. It is determined whether the difference is larger than the difference. When it is determined that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is larger than the first voltage difference (step S601 / YES), the process proceeds to step S603. On the other hand, when it is not determined that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is larger than the first voltage difference (step S601 / NO), the determination process of step S601 is performed. Repeated.

  The first voltage difference is an excessively large difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 (specifically, the power supply control at the time of failure of the DCDC converter 30 described above). Is large enough to make it difficult to sufficiently increase the decreasing speed of the difference between the voltage V1 and the voltage V2).

  For example, the upper limit of the power that can be consumed by the driving motor 50 connected to the first secondary battery 10 changes according to the temperature of the driving motor 50 as described above. The upper limit value of the current that can flow from the drive motor 50 to the drive motor 50 changes according to the temperature of the drive motor 50. Therefore, from the viewpoint of appropriately determining whether the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is excessively large, the control unit 120 includes, for example, the driving motor 50 It is preferable to change the first voltage difference according to an index value having a correlation with the temperature. As an index value having a correlation with the temperature of the driving motor 50, for example, a detection result of the outside air temperature sensor 73 may be used, but other information such as information directly indicating the temperature of the driving motor 50 may be used. May be used.

  If YES is determined in step S601, in step S603, converter control unit 121 causes power to be supplied from the higher voltage secondary battery to the lower voltage secondary battery.

  For example, when voltage V1 is higher than voltage V2, converter control unit 121 causes first secondary battery 10 to supply power to second secondary battery 20. As a result, the voltage V1 decreases as the remaining capacity of the first secondary battery 10 decreases, and the voltage V2 increases as the remaining capacity of the second secondary battery 20 increases. Therefore, the difference between voltage V1 and voltage V2 decreases.

  On the other hand, when voltage V2 is higher than voltage V1, converter control unit 121 causes second secondary battery 20 to supply power to first secondary battery 10. As a result, the voltage V2 decreases as the remaining capacity of the second secondary battery 20 decreases, and the voltage V1 increases as the remaining capacity of the first secondary battery 10 increases. Therefore, the difference between voltage V1 and voltage V2 decreases.

  Next, in step S605, the control unit 120 determines whether or not the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is equal to or less than the first voltage difference. When it is determined that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is equal to or less than the first voltage difference (step S605 / YES), the control flow shown in FIG. finish. On the other hand, when it is not determined that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is equal to or less than the first voltage difference (step S605 / NO), the determination process of step S605 Is repeated.

[2-3. Power supply control when stopping the power supply system]
Next, the power supply control performed by the control unit 120 when stopping the power supply system 1 will be described with reference to FIG.

  As described above, as the switching element of the DCDC converter 30, a switching element that is closed when power is not supplied is used. Here, when the power supply system 1 is stopped, as in the case of the failure of the DCDC converter 30, it becomes impossible to energize each switching element for controlling the operation of the switching element (in other words, it becomes a non-energized state). . Therefore, when the power supply system 1 is stopped, each switching element is closed, so that the first secondary battery 10 and the second secondary battery 20 are electrically connected via the DCDC converter 30.

  Therefore, even when the power supply system 1 is stopped, a current corresponding to the difference between the voltage V1 of the first rechargeable battery 10 and the voltage V2 of the second rechargeable battery 20 is the same as when the DCDC converter 30 fails. It is preferable to perform a process for suppressing disconnection of the DCDC converter 30 due to burning due to the flow through the DCDC converter 30. As such processing, specifically, when stopping the power supply system 1, the control unit 120 determines that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is the second voltage. After controlling the operation of the DCDC converter 30 so that the difference becomes equal to or less than the difference, the driving of the DCDC converter 30 is stopped. Hereinafter, the above processing performed by the control unit 120 will be described in detail with reference to FIG.

  FIG. 9 is a flowchart illustrating an example of a flow of processing related to power supply control when the power supply system 1 is stopped among the processing performed by the control unit 120. The control flow shown in FIG. 9 is specifically executed when the DCDC converter 30 is not out of order.

  When the control flow illustrated in FIG. 9 is started, first, in step S701, the control unit 120 determines whether there is a request to stop the power supply system 1. When it is determined that there is a request to stop the power supply system 1 (step S701 / YES), the process proceeds to step S703. On the other hand, when it is not determined that there is a request to stop the power supply system 1 (step S701 / NO), the determination processing of step S701 is repeated.

  For example, the control unit 120 determines whether there is a request to stop the power supply system 1 based on a signal output from the ignition switch in response to an operation of the ignition switch performed by the driver.

  If YES is determined in step S701, in step S703, control unit 120 determines whether the difference between voltage V1 of first secondary battery 10 and voltage V2 of second secondary battery 20 is larger than the second voltage difference. Is determined. When it is determined that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is larger than the second voltage difference (step S703 / YES), the process proceeds to step S705. On the other hand, if it is not determined that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is larger than the second voltage difference (step S703 / NO), the process proceeds to step S709.

  When the power supply system 1 is stopped and the first secondary battery 10 and the second secondary battery 20 are electrically connected via the DCDC converter 30, the second voltage difference is the difference between the voltage V1 and the voltage V2. Is set to a value that can appropriately determine whether or not the DCDC converter 30 is relatively likely to be disconnected due to burnout due to the current passing through the DCDC converter 30. It may be about the same.

  If YES is determined in step S703, in step S705, converter control unit 121 causes the secondary battery with the higher voltage to supply power to the secondary battery with the lower voltage.

  For example, similarly to step S603 in the control flow of FIG. 8 described above, converter controller 121 causes first secondary battery 10 to supply power to second secondary battery 20 when voltage V1 is greater than voltage V2. When the voltage V2 is higher than the voltage V1, power is supplied from the second secondary battery 20 to the first secondary battery 10. Thereby, the difference between voltage V1 and voltage V2 decreases.

  Next, in step S707, the control unit 120 determines whether or not the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is equal to or less than the second voltage difference. When it is determined that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is equal to or smaller than the second voltage difference (step S707 / YES), the process proceeds to step S709. On the other hand, when it is not determined that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is equal to or smaller than the second voltage difference (step S707 / NO), the determination process of step S707 Is repeated.

  If YES is determined in step S707, converter control section 121 stops driving DC-DC converter 30 in step S709. Thereby, the power supply system 1 can be stopped in a state where the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is equal to or less than the second voltage difference.

  Next, the control flow shown in FIG. 9 ends.

<3. Effect of control device>
Subsequently, effects of the control device 100 according to the embodiment of the present invention will be described.

  In the control device 100 according to the present embodiment, when the DCDC converter 30 in which the first secondary battery 10 and the second secondary battery 20 are electrically connected via the DCDC converter 30 fails, the first secondary battery 10 When the difference between the voltage V1 and the voltage V2 of the second secondary battery 20 is larger than the reference difference, the secondary battery connected to the load connected to the first secondary battery 10 or the second secondary battery 20 is connected to the load. Is controlled so that the decreasing speed of the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 increases. Thus, the rate of decrease of the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 can be increased, and the difference between the voltage V1 and the voltage V2 passing through the DCDC converter 30 can be increased. Current can be reduced quickly. Therefore, disconnection of the DCDC converter 30 due to burnout when the DCDC converter 30 fails can be suppressed. Therefore, when the DCDC converter 30 fails, the driving motor 50 using the electric power stored in the second secondary battery 20 can be appropriately driven. Therefore, in the power supply system 1 including two or more power storage devices, the cruising distance can be appropriately secured when the DCDC converter 30 fails.

  In the control device 100 according to the present embodiment, when the DCDC converter 30 fails, the control unit 120 determines that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is smaller than the reference difference. When the voltage is large and the voltage V1 of the first secondary battery 10 is higher than the voltage V2 of the second secondary battery 20, the current flowing from the first secondary battery 10 to the first load 61 is the same as when the DCDC converter 30 does not fail. It is preferable to increase in comparison. Thereby, the voltage V1 of the first secondary battery 10 can be reduced. Therefore, the rate of decrease in the difference between the voltage V1 of the first rechargeable battery 10 and the voltage V2 of the second rechargeable battery 20 can be appropriately increased, so that the first rechargeable battery 10 to the second rechargeable battery 20 The current passing through the DC-DC converter 30 in the direction toward can be rapidly reduced. Therefore, disconnection of the DCDC converter 30 due to burnout when the DCDC converter 30 fails can be appropriately suppressed.

  Further, in the above-described control (that is, in the above-described first current adjustment control), when the current flowing from the first secondary battery 10 to the driving motor 50 is increased, the voltage V1 when the failure of the DCDC converter 30 occurs. Even when the difference between the DCDC converter 30 and the voltage V2 is relatively large, disconnection of the DCDC converter 30 due to burnout can be appropriately suppressed. In addition, when the current flowing from the first secondary battery 10 to a load other than the drive motor 50 is increased, breakage and deterioration of the drive motor 50 can be suppressed. In addition, according to the above control, even if a request to supply power to the first load 61 has not occurred, the power stored in the first secondary battery 10 is stored in the By supplying the voltage to the one load 61, the rate of decrease in the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 can be increased.

  In the control device 100 according to the present embodiment, the control unit 120 controls the current flowing from the first secondary battery 10 to the first load 61 to DCDC in the above-described control (that is, the above-described first current adjustment control). When the converter 30 is increased in comparison with the non-failure state of the converter 30, the current flowing through the driving motor 50 of the first load 61 increases, and the current flowing through the load other than the driving motor 50 of the first load 61. It is preferable to determine which of the two is to be prioritized according to the state of the power supply system 1. This makes it possible to achieve both the advantages described above when increasing the current flowing through the driving motor 50 and increasing the current flowing through loads other than the driving motor 50.

  In the control device 100 according to the present embodiment, when the DCDC converter 30 fails, the control unit 120 determines that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is smaller than the reference difference. When the voltage is large and the voltage V1 of the first secondary battery 10 is higher than the voltage V2 of the second secondary battery 20, the current flowing from the second secondary battery 20 to the second load 62 will It is preferable to decrease it in comparison. Thereby, a decrease in the voltage V2 of the second secondary battery 20 can be suppressed. Therefore, the rate of decrease in the difference between the voltage V1 of the first rechargeable battery 10 and the voltage V2 of the second rechargeable battery 20 can be appropriately increased, so that the first rechargeable battery 10 to the second rechargeable battery 20 The current passing through the DC-DC converter 30 in the direction toward can be rapidly reduced. Therefore, disconnection of the DCDC converter 30 due to burnout when the DCDC converter 30 fails can be appropriately suppressed.

  Further, according to the above-described control (that is, the above-described second current adjustment control), it is possible to increase the decreasing speed of the difference between the voltage V1 and the voltage V2 while suppressing an increase in the current flowing through the driving motor 50. Therefore, the damage and deterioration of the driving motor 50 can be suppressed.

  In the control device 100 according to the present embodiment, when the DCDC converter 30 fails, the control unit 120 determines that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is smaller than the reference difference. When the voltage is large and the voltage V2 of the second rechargeable battery 20 is higher than the voltage V1 of the first rechargeable battery 10, the current flowing from the second rechargeable battery 20 to the second load 62 is determined when the DCDC converter 30 is in a non-failure state. It is preferable to increase in comparison. Thus, the voltage V2 of the second secondary battery 20 can be reduced. Therefore, the rate of decrease in the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 can be appropriately increased, so that the first secondary battery 10 The current passing through the DC-DC converter 30 in the direction toward can be rapidly reduced. Therefore, disconnection of the DCDC converter 30 due to burnout when the DCDC converter 30 fails can be appropriately suppressed.

  Further, according to the above control (that is, the above-described third current adjustment control), it is possible to increase the decreasing speed of the difference between the voltage V1 and the voltage V2 while suppressing a decrease in the current flowing through the driving motor 50. Therefore, it is possible to suppress a decrease in the output of the driving motor 50 and a sense of incongruity given to the driver. Further, according to the above control, even if a request to supply power to the second load 62 has not occurred, the power stored in the second secondary battery 20 is reduced to the second power regardless of the request. By supplying the voltage to the two loads 62, the rate of decrease in the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 can be increased.

  In the control device 100 according to the present embodiment, when the DCDC converter 30 fails, the control unit 120 determines that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is smaller than the reference difference. When the voltage is large and the voltage V2 of the second rechargeable battery 20 is higher than the voltage V1 of the first rechargeable battery 10, the current flowing from the first rechargeable battery 10 to the first load 61 is determined as the time when the DCDC converter 30 does not fail. It is preferable to decrease it in comparison. Thereby, a decrease in the voltage V1 of the first secondary battery 10 can be suppressed. Therefore, the rate of decrease in the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 can be appropriately increased, so that the first secondary battery 10 The current passing through the DC-DC converter 30 in the direction toward can be rapidly reduced. Therefore, disconnection of the DCDC converter 30 due to burnout when the DCDC converter 30 fails can be appropriately suppressed.

  Further, in the above control (that is, the above-described fourth current adjustment control), when the current flowing from the first secondary battery 10 to the drive motor 50 is reduced, the voltage V1 of the first secondary battery 10 and the second Since the rate of decrease in the difference between the voltage V2 of the secondary battery 20 and the voltage V2 can be more effectively increased, the difference between the voltage V1 and the voltage V2 when the failure of the DCDC converter 30 occurs is relatively large. However, disconnection of the DCDC converter 30 due to burning can be appropriately suppressed. When the request for driving the driving motor 50 has not been issued, the current flowing from the first secondary battery 10 to the load of the first load 61 other than the driving motor 50 is reduced, thereby reducing the first load. The rate of decrease in the difference between the voltage V1 of the secondary battery 10 and the voltage V2 of the second secondary battery 20 can be increased.

  In the control device 100 according to the present embodiment, when the DCDC converter 30 fails, the control unit 120 determines that the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is smaller than the reference difference. If it is large, it is possible to control the current flowing from the secondary battery connected to the load to the first secondary battery 10 or the second secondary battery 20 based on the current passing through the DCDC converter 30. preferable. Thereby, the decreasing speed of the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 can be appropriately increased according to the magnitude of the current passing through the DCDC converter 30. . Therefore, when the DCDC converter 30 fails, it is possible to more appropriately suppress the DCDC converter 30 from being broken due to burnout due to the current passing through the DCDC converter 30.

  In the control device 100 according to the present embodiment, the control unit 120 determines that the difference between the voltage V1 of the first rechargeable battery 10 and the voltage V2 of the second It is preferable to control the operation of the DCDC converter 30 so that the voltage difference is equal to or less than the voltage difference. Thereby, it is possible to prevent the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 from becoming excessively large when the failure of the DCDC converter 30 occurs. Therefore, it is possible to prevent the current passing through the DCDC converter 30 from becoming excessively large when the DCDC converter 30 fails. Therefore, when the DCDC converter 30 fails, it is possible to more appropriately suppress the DCDC converter 30 from being broken due to burning due to the current passing through the DCDC converter 30.

  In the control device 100 according to the present embodiment, it is preferable that the control unit 120 changes the first voltage difference according to an index value having a correlation with the temperature of the driving motor 50. Thereby, it is possible to appropriately determine whether or not the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is excessively large according to the temperature of the driving motor 50.

  In the control device 100 according to the present embodiment, when the power supply system 1 is stopped, the control unit 120 determines that the difference between the voltage V1 of the first rechargeable battery 10 and the voltage V2 of the second After controlling the operation of the DCDC converter 30 so that the voltage difference becomes equal to or less than the voltage difference, it is preferable to stop driving the DCDC converter 30. Thereby, the power supply system 1 can be stopped in a state where the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is equal to or less than the second voltage difference. Therefore, when the power supply system 1 is stopped, the first secondary battery 10 and the second secondary battery 20 are electrically connected to each other via the DCDC converter 30, so that a current flows through the DCDC converter 30. As a result, it is possible to prevent the DCDC converter 30 from being disconnected due to burnout.

<4. Conclusion>
As described above, in the control device 100 according to the present embodiment, when the DCDC converter 30 in which the first secondary battery 10 and the second secondary battery 20 are electrically connected via the DCDC converter 30 fails, When the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 is larger than the reference difference, the load connected to the first secondary battery 10 or the second The current flowing from the connected secondary battery is controlled so that the decreasing speed of the difference between the voltage V1 of the first secondary battery 10 and the voltage V2 of the second secondary battery 20 increases. Accordingly, when the DCDC converter 30 fails, the current flowing in the DCDC converter 30 can suppress the DCDC converter 30 from being broken due to burnout. 50 can be appropriately driven. Therefore, in the power supply system 1 including two or more power storage devices, the cruising distance can be appropriately secured when the DCDC converter 30 fails.

  As described above, the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to such examples. It is apparent that those skilled in the art to which the present invention pertains can conceive various modifications or applications within the scope of the technical idea described in the claims. It is understood that these also belong to the technical scope of the present invention.

  For example, the processes described using a flowchart in this specification do not necessarily have to be executed in the order shown in the flowchart. Some processing steps may be performed in parallel. Further, additional processing steps may be employed, and some processing steps may be omitted.

Reference Signs List 1 power supply system 10 first secondary battery 20 second secondary battery 30 DCDC converter 40 inverter 50 driving motor 61 first load 62 second load 71 first battery sensor 72 second battery sensor 73 outside temperature sensor 74 converter current sensor Reference Signs List 100 control device 110 acquisition unit 120 control unit 121 converter control unit 122 first load control unit 123 second load control unit

Claims (10)

A first power storage device connected to the driving motor;
A second power storage device connected to the first power storage device via a voltage converter,
With
When the voltage converter fails, the first power storage device and the second power storage device are electrically connected via the voltage converter.
A control device for a power supply system,
The control device includes a control unit that controls supply of power in the power supply system,
The control unit, when a failure of the voltage converter, a difference between the voltage of the first power storage device and the voltage of the second power storage device is larger than a reference difference, the first power storage device or the second power storage device Controlling the current flowing from the power storage device connected to the load to the connected load such that the decreasing speed of the difference between the voltage of the first power storage device and the voltage of the second power storage device increases;
Power system control device. The first power storage device is connected to a first load including the driving motor,
When the voltage converter fails, a difference between the voltage of the first power storage device and the voltage of the second power storage device is larger than the reference difference, and the voltage of the first power storage device is the second power storage device. (2) When the voltage is larger than the voltage of the power storage device, the current flowing from the first power storage device to the first load is increased as compared with a time when the voltage converter is not out of order.
A control device for a power supply system according to claim 1. The control unit is configured to, when increasing a current flowing from the first power storage device to the first load as compared with a non-failure state of the voltage converter, a current flowing to the drive motor of the first load. Which of the first load and the increase of the current flowing to loads other than the drive motor among the first loads is determined according to the state of the power supply system.
A control device for a power supply system according to claim 2. The second power storage device is connected to a second load,
When the voltage converter fails, a difference between the voltage of the first power storage device and the voltage of the second power storage device is larger than the reference difference, and the voltage of the first power storage device is the second power storage device. (2) When the voltage is higher than the voltage of the power storage device, the current flowing from the second power storage device to the second load is reduced as compared with a non-failure state of the voltage converter.
A control device for a power supply system according to claim 1. The second power storage device is connected to a second load,
The control unit may be configured such that when the voltage converter fails, a difference between the voltage of the first power storage device and the voltage of the second power storage device is larger than the reference difference, and the voltage of the second power storage device is the second power storage device. When the voltage is larger than the voltage of the one power storage device, the current flowing from the second power storage device to the second load is increased as compared with a time when the voltage converter is not out of order.
A control device for a power supply system according to claim 1. The first power storage device is connected to a first load including the driving motor,
The control unit may be configured such that, when the voltage converter fails, a difference between the voltage of the first power storage device and the voltage of the second power storage device is larger than the reference difference, and the voltage of the second power storage device is the second power storage device. When the voltage is higher than the voltage of the first power storage device, the current flowing from the first power storage device to the first load is reduced as compared with a non-failure state of the voltage converter.
A control device for a power supply system according to claim 1. The control unit is configured to, when the voltage converter fails, when the difference between the voltage of the first power storage device and the voltage of the second power storage device is larger than the reference difference, the first power storage device or the second power storage device A current flowing from a power storage device connected to the load connected to the load is controlled based on a current passing through the voltage converter.
A control device for a power supply system according to claim 1. The control unit controls the operation of the voltage converter such that a difference between the voltage of the first power storage device and the voltage of the second power storage device is equal to or less than a first voltage difference when the voltage converter is not out of order. Control,
A control device for a power supply system according to claim 1. The control unit changes the first voltage difference according to an index value having a correlation with the temperature of the driving motor,
A control device for a power supply system according to claim 8. When stopping the power supply system, the control unit controls the operation of the voltage converter such that a difference between the voltage of the first power storage device and the voltage of the second power storage device is equal to or less than a second voltage difference. Later, the driving of the voltage converter is stopped,
A control device for a power supply system according to claim 1.

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