Electric power system

Abstract

To enable a stable retreat travel for a relatively long distance even in the case of trouble.SOLUTION: An electric power system includes: a high-voltage battery connected to a driving device via a high-voltage system power line; a low-voltage battery connected to auxiliary equipment via a low-voltage system power line; a main power converter connected to the high-voltage system power line and the low-voltage system power line; and a bidirectional charger having a battery charger power converter connected to an external power side and the high-voltage system power line to increase / decrease the power and supply the power, and charging the high-voltage battery and supplying the voltage of the high-voltage battery to the external electric load. The electric power system steps down the power of the high-voltage system power line by the battery charger power converter to supply the power to the low-voltage system power line when detecting trouble in the main power converter.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a power supply system, and more particularly to an in-vehicle power supply system including a high-voltage battery and a low-voltage battery.

Background Art

[0002] Conventionally, as this type of power supply system, there has been proposed a system including a high-voltage battery attached to a high-voltage power line connected to an inverter that drives a motor for running, a low-voltage battery connected to an auxiliary machine by a low-voltage power line, and a bidirectional DC / DC converter connected to the high-voltage power line and the low-voltage power line to step up and down the voltage and supply it (see, for example, Patent Document 1). In this system, there are provided a charger connected to the high-voltage power line to charge the high-voltage battery with external power, and an AC / DC converter connected to the low-voltage power line to supply power to the outside.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described power supply system, when the bidirectional DC / DC converter fails, the low-voltage battery can only drive the auxiliary machine until the voltage reaches a voltage at which the auxiliary machine can be driven, and the evacuation running of the vehicle becomes short. Also, when the low-voltage battery fails, although power can be supplied to the low-voltage power line by the bidirectional DC / DC converter, the voltage of the low-voltage power line is not stabilized, and there may be a case where the driving of the auxiliary machine is not stable.

[0005] The main purpose of the power supply system of the present disclosure is to enable stable evacuation driving over a relatively long distance even in case of a failure.

Means for Solving the Problems

[0006] The power supply system of the present disclosure has adopted the following means to achieve the above-mentioned main purpose.

[0007] The power supply system of the present disclosure includes a high-voltage battery connected to a drive device for driving a vehicle by a high-voltage power line, a low-voltage battery connected to an in-vehicle auxiliary machine by a low-voltage power line, a main power converter connected to the high-voltage power line and the low-voltage power line to step up and down the power and supply it, a bidirectional charger connected to the high-voltage power line to charge the high-voltage battery with external power or supply the voltage of the high-voltage battery to an external electrical load, a control device for controlling the main power converter and the bidirectional charger, and is an in-vehicle power supply system comprising wherein the bidirectional charger has a charger power converter connected to the external power side and the high-voltage power line to step up and down the power and supply it, the charger power converter is connected to the low-voltage power line, and when the control device detects a failure in the main power converter, the control device controls the charger power converter to step down the power of the high-voltage power line by the charger power converter and supply it to the low-voltage power line. This is the feature.

[0008] The power supply system of the present disclosure includes a high-voltage battery connected to a drive device for driving a vehicle by a high-voltage power line, a low-voltage battery connected to in-vehicle auxiliary equipment by a low-voltage power line, a main power converter connected to the high-voltage power line and the low-voltage power line for stepping up and down the voltage and supplying the power, a bidirectional charger connected to the high-voltage power line for charging the high-voltage battery with external power or supplying the voltage of the high-voltage battery to an external electrical load, and a control device for controlling a step-down power converter and the bidirectional charger. The bidirectional charger is provided with a charger power converter connected to the external power side and the high-voltage power line for stepping up and down the voltage and supplying the power, and this charger power converter is connected to the low-voltage power line. And when the control device detects a failure in the main power converter, the control device controls the charger power converter to step down the power of the high-voltage power line by the charger power converter and supply it to the low-voltage power line. Thereby, even if a failure occurs in the main power converter, the power of the high-voltage power line can be stepped down and supplied to the low-voltage power line. As a result, even when the main power converter fails, it is possible to stably perform a standby travel for a relatively long distance.

[0009] In the power supply system of the present disclosure, an equipotential line connecting an intermediate potential portion having the same potential as the reference potential of the low-voltage power line of the high-voltage battery and the low-voltage power line, and a relay attached to the equipotential line are provided. When the control device detects a failure in the low-voltage battery, the control device may control to turn on the relay so that power is supplied to the low-voltage power line through the equipotential line. By doing so, even if a failure occurs in the low-voltage battery, the voltage of the low-voltage power line can be stabilized. As a result, even when the low-voltage battery fails, it is possible to stably perform a standby travel for a relatively long distance.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0011] Next, a mode (embodiment) for carrying out the present disclosure will be described. FIG. 1 is a configuration diagram showing an outline of the configuration of a power supply system 20 as an embodiment of the present disclosure. The power supply system 20 of the embodiment is configured as an in-vehicle system that supplies power to a drive device 12 for vehicle travel including a three-phase AC motor and an inverter. The power supply system 20 includes a high-voltage battery 22, a DC / DC converter 28, an auxiliary battery 32, an auxiliary machine 36, a bidirectional charger 40, and an electronic control unit 60.

[0012] The high-voltage battery 22 is configured as a battery pack using, for example, a lithium-ion secondary battery of 200V or 400V, and is connected to the drive device 12 by a high-voltage power line 24. A system main relay 26 is attached to the high-voltage power line 24, and the high-voltage battery 22 can be connected or disconnected by turning the system main relay 26 on and off. The intermediate potential part having the same potential as the reference potential of the auxiliary battery 32 from the ground of the high-voltage battery 22 is connected to the low-voltage power line 34 by a second connection line 50. An equipotential connection relay 52 is attached to this second connection line 50, and the equipotential connection relay 52 is normally turned off.

[0013] The auxiliary battery 32 is configured as, for example, a 12V lead battery and is connected to the auxiliary machine 36 by the low-voltage power line 34.

[0014] The DC / DC converter 28 is configured as a well-known step-up / step-down DC / DC converter, and converts the voltage between the high-voltage power line 24 and the low-voltage power line 34 to supply power bidirectionally. Usually, the DC / DC converter 28 steps down the power on the high-voltage power line 24 side and supplies it to the low-voltage power line 34.

[0015] The bidirectional charger 40 includes a connector 42 connected to an external commercial power supply, an inverter 44 connected to the connector 42, a DC / DC converter 46 connected to the inverter 44 and also connected to the high-voltage power line 24, and a socket 48 connected to the inverter 44 to supply power to an external electrical load. The inverter 44 is configured as a well-known inverter, and converts the AC power of the commercial power supply into DC power and supplies it to the DC / DC converter 46, or converts the DC power supplied from the DC / DC converter 46 into AC power and supplies it to the socket 48. The DC / DC converter 46 is configured as a well-known step-up / step-down DC / DC converter, steps up the DC power from the inverter 44 and supplies it to the high-voltage power line 24, or steps down the DC power from the high-voltage power line 24 and supplies it to the inverter 44. The DC / DC converter 46 is also connected to the low-voltage power line 34 by the first connection line 49, and can step down the DC power from the high-voltage power line 24 and supply it to the low-voltage power line 34.

[0016] The electronic control unit 60 is configured as a microcomputer centered around a CPU (not shown), and includes a ROM, a RAM, a flash memory, an input port, an output port, a communication port, etc. in addition to the CPU. From the electronic control unit 60, drive control signals to the DC / DC converter 28, drive control signals to the bidirectional charger 40, drive control signals to the system main relay 26, drive control signals to the equipotential connection relay 52, etc. are output from the output port.

[0017] Next, the operation of the power supply system 20 configured in this way will be described, particularly the operation when a failure occurs in the DC / DC converter 28 or the auxiliary battery 32. FIG. 2 is a flowchart showing an example of the failure-time processing executed by the electronic control unit 60. This processing is repeatedly executed at predetermined time intervals.

[0018] When the failure-time processing is executed, the electronic control unit 60 first determines whether a failure has occurred in the DC / DC converter 28 (step S100). Whether a failure has occurred in the DC / DC converter 28 can be determined by examining the value of the DC / DC converter failure diagnosis flag, which becomes 1 when a failure occurs as a result of a failure diagnosis (not shown) of the DC / DC converter 28 and 0 when no failure has occurred. Since the failure diagnosis of the DC / DC converter 28 is not the core of the present disclosure, its detailed description will be omitted.

[0019] When it is determined in step S100 that a failure has occurred in the DC / DC converter 28, the DC / DC converter 46 of the bidirectional charger 40 is driven so as to step down the power of the high-voltage power line 24 and supply it to the low-voltage power line 34 (step S110), and this processing is terminated. A schematic diagram of the state in which the DC / DC converter 28 has failed and the DC / DC converter 46 of the bidirectional charger 40 steps down the power of the high-voltage power line 24 and supplies it to the low-voltage power line 34 is shown in FIG. 3. In the figure, the cross mark of the DC / DC converter 28 indicates a failure, and the thick solid arrow indicates the power supply direction. By driving the DC / DC converter 46 of the bidirectional charger 40 even when a failure occurs in the DC / DC converter 28, the auxiliary machine 36 can be driven until the high-voltage battery 22 is substantially completely discharged, as compared with the state where the auxiliary machine 36 can only be driven until the voltage of the auxiliary battery 32 drops to a voltage at which the auxiliary machine 36 can be driven.

[0020] When it is determined in step S100 that no failure has occurred in the DC / DC converter 28, it is determined whether or not a failure has occurred in the auxiliary battery 32 (step S120). When it is determined that a failure has occurred in the auxiliary battery 32, the equipotential connection relay 52 is turned on (step S130), and this process ends. FIG. 4 schematically shows a state when the auxiliary battery 32 fails and the second connection line 50 connects the intermediate potential portion, which is equipotential with the reference potential of the auxiliary battery 32 of the high-voltage battery 22, and the low-voltage power line 34. In the figure, the thick solid line arrow passing through the DC / DC converter 28 indicates the power supply direction, and the thick solid line bidirectional arrow of the second connection line 50 indicates the power supply. Thus, even when a failure occurs in the auxiliary battery 32, by connecting the intermediate potential portion, which is equipotential with the reference potential of the auxiliary battery 32 of the high-voltage battery 22, and the low-voltage power line 34 by the second connection line 50, the voltage (potential) of the low-voltage power line 34 can be made stable even when power supply by the DC / DC converter 28 and power consumption by the auxiliary machine 36 are performed.

[0021] In the power supply system 20 of the embodiment described above, when a failure occurs in the DC / DC converter 28, the DC / DC converter 46 of the bidirectional charger 40 is driven so as to step down the power of the high-voltage power line 24 and supply it to the low-voltage power line 34. Thereby, compared with a state in which the auxiliary machine 36 can be driven only until the voltage of the auxiliary battery 32 drops to a voltage at which the auxiliary machine 36 can be driven, the auxiliary machine 36 can be driven until the high-voltage battery 22 is substantially completely discharged. As a result, even when a failure occurs in the DC / DC converter 28, it is possible to stably perform an evacuation travel for a relatively long distance.

[0022] In the power supply system 20 of the embodiment, when a failure occurs in the auxiliary battery 32, the equipotential connection relay 52 is turned on. Thereby, the voltage (potential) of the low-voltage power line 34 can be made stable even when power supply by the DC / DC converter 28 and power consumption by the auxiliary machine 36 are performed.

[0023] In the power supply system 20 of the embodiment, the second connection line 50 connects the intermediate potential part having the same potential as the reference potential of the auxiliary battery 32 of the high-voltage battery 22 and the low-voltage system power line 34, and an equipotential connection relay 52 is provided on the second connection line 50. When a failure occurs in the auxiliary battery 32, the equipotential connection relay 52 is turned on. However, the second connection line 50 and the equipotential connection relay 52 may not be provided.

[0024] The correspondence between the main elements of the embodiment and the main elements of the invention described in the section of means for solving the problems will be described. In the embodiment, the drive device 12 corresponds to the "drive device", the high-voltage system power line 24 corresponds to the "high-voltage system power line", the high-voltage battery 22 corresponds to the "high-voltage battery", the auxiliary machine 36 corresponds to the "auxiliary machine", the low-voltage system power line 34 corresponds to the "low-voltage system power line", the auxiliary battery 32 corresponds to the "low-voltage battery", the DC / DC converter 28 corresponds to the "main power converter", the bidirectional charger 40 corresponds to the "bidirectional charger", the electronic control unit 60 corresponds to the "control device", and the DC / DC converter 46 corresponds to the "power converter for charger".

[0025] Note that the correspondence between the main elements of the embodiment and the main elements of the invention described in the section of means for solving the problems is an example for specifically explaining the form for implementing the invention described in the section of means for solving the problems in the embodiment. Therefore, it does not limit the elements of the invention described in the section of means for solving the problems. That is, the interpretation of the invention described in the section of means for solving the problems should be made based on the description in that section, and the embodiment is only a specific example of the invention described in the section of means for solving the problems.

[0026] As described above, the present disclosure has been described using the embodiments. However, the present disclosure is not limited to such embodiments, and it goes without saying that the present disclosure can be implemented in various forms without departing from the gist of the present disclosure.

Industrial Applicability

[0027] This disclosure can be used in the manufacturing industry of power systems and the like.

Description of Reference Numerals

[0028] 12 Drive device, 20 Power system, 22 High-voltage battery, 24 High-voltage power line, 26 System main relay, 28 DC / DC converter, 32 Auxiliary battery, 34 Low-voltage power line, 36 Auxiliary machine, 40 Bidirectional charger, 42 Connector, 44 Inverter, 46 DC / DC converter, 48 Socket, 49 First connection line, 50 Second connection line, 52 Equipotential connection relay, 60 Electronic control unit.

Claims

1. A high-voltage battery connected to a drive device for driving a vehicle by a high-voltage power line, A low-voltage battery connected to an in-vehicle auxiliary machine by a low-voltage power line, A main power converter connected to the high-voltage power line and the low-voltage power line to step up and down the power and supply it, A bidirectional charger connected to the high-voltage power line to charge the high-voltage battery with external power or supply the voltage of the high-voltage battery to an external electrical load, A control device for controlling the main power converter and the bidirectional charger, An in-vehicle power supply system comprising: The bidirectional charger has a charger power converter connected to the external power side and the high-voltage power line to step up and down the power and supply it, The charger power converter is connected to the low-voltage power line, When the control device detects a failure in the main power converter, the control device controls the charger power converter to step down the power of the high-voltage power line and supply it to the low-voltage power line by the charger power converter. A power supply system characterized by the above.

2. The power supply system according to claim 1, An equipotential line connecting an intermediate potential portion having the same potential as the reference potential of the low-voltage power line of the high-voltage battery and the low-voltage power line, A relay attached to the equipotential line, Comprising: When the control device detects a failure in the low-voltage battery, the control device turns on the relay and controls the power to be supplied to the low-voltage power line by the equipotential line. A power supply system.

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