JP2023079775A - Power supply system and method for controlling power supply system - Google Patents

Abstract

To provide a power supply system and a method for controlling the power supply system that prevent the discharge of an additional battery due to a dark current in a load.SOLUTION: A power supply system, which is installed in a vehicle having a normal driving mode by a driver and an autonomous driving mode, comprises a first load circuit, a second load circuit, a first relay, a second relay, and a controller. The first load circuit is connected to a first load, which operates with electric power from a main battery and is required for continuation of the normal driving mode. The second load circuit is connected to a second load, which operates with electric power from the main battery or an additional battery and is required for continuation of the autonomous driving mode. The first relay is provided to a feeder connecting the first and second loads to allow or disallow conduction between the first and second load circuits. The second relay allows or disallows conduction between the additional battery and the second load. The controller determines whether the driving mode of the vehicle is the normal driving mode or the autonomous driving mode.SELECTED DRAWING: Figure 1

Description

The present invention relates to a power supply system and a control method for the power supply system.

Conventionally, there is known a control method for an automatic driving vehicle power supply having a circuit disconnection mechanism between a first load circuit powered by a main battery and a second load circuit powered by an additional battery (Patent Document 1). . The first load circuit is connected to the load necessary for the driver to continue the normal operation mode, and the second load circuit is connected to the automatic load circuit necessary to continue the automatic operation mode and to maintain the voltage. A driving function load is connected. In this method for controlling the power source of an automatic driving vehicle, it is determined that power is taken out from the additional battery to the first load circuit side based on the load state detected on the second load circuit side while the circuit disconnection mechanism is connected. Then, the circuit disconnecting mechanism is interrupted.

JP 2017-177857 A

In the method for controlling the power source of an automatic driving vehicle described in Patent Document 1, since the connection between the additional battery and the load cannot be cut off, there is a problem that the additional battery is discharged due to the dark current of the load.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a power system and a method of controlling the power system that prevent the additional battery from being discharged due to the dark current of the load.

The present invention is a power supply system mounted on a vehicle having a normal operation mode by a driver and an automatic operation mode. A first load circuit, a second load circuit operated by power from the main battery or an additional battery and connected to a second load necessary for continuing the automatic operation mode, and electrically connecting the first load and the second load A first relay provided on a connected power supply line for conducting or interrupting between a first load circuit and a second load circuit, a second relay for conducting or interrupting between an additional battery and a second load, and a vehicle operation mode. The above problem is solved by providing a controller that determines whether is the normal operation mode or the automatic operation mode.

According to the present invention, since the second relay can disconnect the additional battery from the load, it is possible to prevent the additional battery from being discharged due to the dark current of the load.

FIG. 1 is a schematic diagram of the configuration of the power supply system according to this embodiment. 2A is a flow chart showing an example of a procedure of a power system control method executed by the controller shown in FIG. 1; FIG. 2B is a flow chart showing an example of a procedure of a control method for the power supply system executed by the controller shown in FIG. 1; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a power supply system and a control method for the power supply system according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a power supply system 100 according to this embodiment. In the present embodiment, as a vehicle equipped with the power supply system 100, a vehicle having an engine as a drive source and an autonomous driving control function will be described as an example. A vehicle equipped with an autonomous driving control function has a normal driving mode and an automatic driving mode as driving modes. When the normal driving mode is set, the vehicle runs according to the driver's driving operation (steering operation, accelerator operation, brake operation, etc.). On the other hand, when the automatic driving mode is set, the vehicle is driven not only by the driver but also by a driving assistance device (not shown).

In the automatic driving mode, the content of the driving assistance realized by the autonomous driving control function may differ according to the driving assistance level. The driving assistance level is a level indicating the degree of intervention when the driving assistance device assists the driving of the vehicle by the autonomous driving control function. The higher the driving assistance level, the lower the driver's contribution to driving the vehicle. Specifically, the driving assistance level can be set using a definition based on SAE J3016 of the Society of Automotive Engineers (SAE). In this embodiment, the driving assistance level realized by the driving assistance device is described as driving assistance level 2. FIG. Furthermore, in the present embodiment, a vehicle having a mode (also referred to as a hands-off mode) in which the vehicle autonomously travels without the driver touching the steering wheel will be described as an example. In hands-off mode, the driving assistance device performs some driving tasks on behalf of the driver, but the driver regains control of driving and drives manually when requested by the driving assistance device. I need to prepare. Also, in the hands-off mode, a redundant function is required to continue autonomous driving until the driver performs a driving operation in response to a request from the driving support device. To give an example of a redundant function, for example, a vehicle having an autonomous driving mode is provided with an additional battery that functions as a backup power source for the load required for the autonomous cruise control function.

However, when the additional battery is installed, there is also the problem that the additional battery is discharged by the dark current of the load connected to the additional battery while the ignition switch of the vehicle is in the OFF state. As the dark current of the load causes the additional battery to discharge, the remaining battery capacity of the additional battery decreases, and in automatic operation mode, the power required to continue autonomous driving cannot be supplied to the load, and it functions as a backup power supply source. sometimes not. In the power supply system and power supply system control method according to the present invention, the configuration and method described below prevent the additional battery from being discharged due to the dark current of the load, and in the automatic operation mode, the power required to continue autonomous driving is supplied to the load. can be supplied to In addition, henceforth, said driving assistance device is demonstrated as a structure included in an advanced driving assistance system (ADAS:Advanced Driver Assistance System).

As shown in FIG. 1 , the power supply system 100 includes a first load circuit 1 , a second load circuit 2 , a feeder line 3 , a main relay 4 , an additional relay 5 and a controller 6 .

The first load circuit 1 is a load circuit that operates with power from a lead battery 11 (main battery) or an alternator 14 and is connected to a first load necessary for continuing the normal operation mode. In this embodiment, the first load circuit 1 includes a lead battery 11 connected to the power supply line 3, a load actuator 12, a starter motor 13, and an alternator 14, as shown in FIG. The load actuator 12 and the starter motor 13 are examples of the first load required to continue the normal operation mode.

The lead battery 11 is a secondary battery as a main battery conventionally installed in an engine vehicle. The lead battery 11 is charged by an alternator 14 as a power generator so that the remaining battery level does not decrease. The alternator 14 generates power by means of a rotation drive mechanism (not shown) driven by the engine, and charges the lead battery 11 so that the battery remaining amount is maintained at a predetermined battery remaining amount or more.

The load actuator 12 is auxiliary equipment that operates with power from the lead battery 11 or power generated by the alternator 14 . Examples of the load actuator 12 include an electric motor that drives a compressor of an air conditioner, a headlight, and the like. When the ignition switch 68 of the vehicle is turned on (hereinafter also referred to as the vehicle drivable state), power stored in the lead battery 11 or power generated by the alternator 14 is supplied to the load actuator 12 . On the other hand, when the ignition switch 68 of the vehicle is turned off (hereinafter also referred to as a parked state of the vehicle), electric power stored in the lead battery 11 is supplied to the load actuator 12 . Note that the state in which the vehicle can travel indicates a state that is not related to the vehicle speed, and includes a state in which the vehicle is traveling and a state in which the vehicle is stopped.

The starter motor 13 is a motor for starting the engine, which starts the engine when the vehicle starts moving, and restarts the engine when idling is stopped.

The second load circuit 2 is a load circuit that operates with power from the lead battery 11 or the lithium ion battery 21 (additional battery) and is connected to a second load necessary for continuing the automatic operation mode. In this embodiment, the second load circuit 2 includes an EPS actuator 22, an ABS actuator 23, an ADAS actuator 24, and a current sensor 61 connected to the power supply line 3, as shown in FIG. The EPS actuator 22, the ABS actuator 23, and the ADAS actuator 24 are examples of the second load required to continue the automatic operation mode. The range of input voltage to these actuators is determined according to the specifications of each actuator. Must be kept within range.

The lithium ion battery 21 is a secondary battery added as a new power source for continuing the autonomous driving control function of the vehicle to the power source of the lead battery 11 . In other words, the lithium ion battery 21 is a backup power supply source that supplies power to each load included in the second load circuit 2 in order to continue autonomous driving in the automatic operation mode. Charging and discharging of the lithium ion battery 21 are controlled by a battery management system (BMS). In the example of FIG. 1, when the main relay 4 and the additional relay 5 are in the ON state, the lithium ion battery 21 and the first load circuit 1 are electrically connected, so the battery management system generates electricity with the alternator 14 (generator). The electric power charges the lithium ion battery 21 . As will be described later, when the controller 6 determines that the driving mode of the vehicle is the automatic driving mode, the main relay 4 is switched from ON to OFF when the circuit voltage of the second load circuit 2 is out of the predetermined voltage range. However, since the additional relay 5 maintains the ON state, the conduction state is maintained between the additional battery and the second load circuit before and after the main relay 4 is switched from ON to OFF. The battery management system outputs the electric power charged by the lithium ion battery 21 to the second load and discharges the lithium ion battery 21 . Once the main relay 4 is switched from ON to OFF in the automatic operation mode, the lithium ion battery 21 is powered by the alternator 14 in order to maintain the OFF state until the automatic operation mode shifts to the normal operation mode. It cannot be charged with the generated power. For this reason, the capacity of the lithium-ion battery 21 is set to an appropriate capacity, for example, so that the duration of running in the automatic driving mode is at least equal to or longer than the required duration.

In addition, the lithium ion battery 21 has a characteristic that the internal resistance is smaller than that of the lead battery 11 . Therefore, for example, even when the EPS actuator 22 operates and consumes a large amount of current, the voltage can be kept high.

The EPS actuator 22 is an EPS motor that generates an electric assist force, and is a load that needs to operate in the automatic operation mode. The EPS actuator 22 is used in an electric power steering system (not shown) that electrically assists the force required for steering operation to lighten the steering force. Here, "EPS" is an abbreviation for "Electric Power Steering".

The ABS actuator 23 is a pump motor that drives a hydraulic pump or an electromagnetic valve, and is a load that needs to operate in the automatic operation mode. The ABS actuator 23 has an electric hydraulic pump and is used in a brake hydraulic pressure control system (not shown) that independently controls the hydraulic pressure of each wheel cylinder based on hydraulic fluid from the master cylinder and hydraulic pump. Here, "ABS" is an abbreviation for "Antilock Brake System."

The ADAS actuator 24 is an actuator that performs various driving operation assists to assist the driver's driving operation, and is a load that needs to operate in the automatic driving mode. ADAS actuators 24 are used in advanced driver assistance systems 70 .

The power supply line 3 is a wire harness that electrically connects the first load circuit 1 and the second load circuit 2 to supply power. Electric power is supplied to the load actuator 12 included in the first load circuit 1 and the EPS actuator 22 , the ABS actuator 23 and the ADAS actuator 24 included in the second load circuit 2 through the feeder line 3 .

The main relay 4 is provided on the feeder line 3 between the first load circuit 1 and the second load circuit 2, and is a circuit connecting/disconnecting mechanism for connecting or disconnecting between the first load circuit 1 and the second load circuit 2. be. One terminal of the main relay 4 is connected to the power supply line 3 on the first load circuit 1 side, and the other terminal of the main relay 4 is connected to the power supply line 3 on the second load circuit 2 side. In this embodiment, a normally open type relay is used as the main relay 4 . Examples of the main relay 4 include mechanical relays (also referred to as mechanical relays) and semiconductor relays. A mechanical relay has contacts and mechanically opens and closes the contacts by electromagnetic action to switch on and off. Semiconductor relays do not have contacts, but are composed of semiconductors and electronic components such as MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), and are switched on and off by electrical signals. In this embodiment, as the main relay 4, a semiconductor relay having a self-interruption/connection function that autonomously switches on and off for overvoltage protection and overcurrent protection will be described as an example.

An opening/closing control signal is input to the main relay 4 from the controller 6, and the main relay 4 is turned on or off according to the input opening/closing control signal. In addition to the opening/closing control signal, the main relay 4 is supplied with a continuity maintenance command or a disconnection command from the controller 6 . Once the continuity maintenance command is input, the main relay 4 continues to maintain the ON state until the release command is input, regardless of whether the opening/closing control signal is input. When a release command is input after the continuity maintenance command is input, the main relay 4 releases the maintenance of the ON state and turns ON or OFF again according to the opening/closing control signal. When the main relay 4 is a semiconductor relay as in the present embodiment, the opening/closing control signal is, for example, a switching signal for switching a semiconductor such as a switching element from on to off or from off to on. The continuity maintenance command is a signal for disabling the self-interruption/connection function and maintaining the ON state, for example, in order to prevent the self-interruption/connection function from switching from ON to OFF. Also, the release command is, for example, a signal for activating the self-shutdown/connection function. As the self-interruption/connection function, for example, the voltage applied between the terminals of the main relay 4 (between the terminal connected to the first load circuit 1 and the terminal connected to the second load circuit 2) is the abnormal voltage. In this case, there is a protection function that switches the main relay 4 from on to off. The abnormal voltage is, for example, a predetermined overvoltage determined by the specifications of the main relay 4 . As for the self-interruption/connection function, for example, when the current flowing through the main relay 4 (the current flowing from the first load circuit 1 side to the second load circuit 2 side) is an abnormal current, the main relay 4 is turned off from on. switching protection functions. The abnormal current is, for example, a predetermined overcurrent defined by the specifications of the main relay 4 . In the following description, "on (on state) of the main relay 4" means that the terminals of the main relay 4 are electrically connected, and "off (off state) of the main relay 4" means that the main relay 4 is turned off. 4 is insulated (disconnected) between terminals.

The additional relay 5 is electrically connected to the power supply line 3 on the side of the second load circuit 2, and is for conducting or interrupting between the lithium ion battery 21 and the EPS actuator 22, the ABS actuator 23, and the ADAS actuator 24. It is a battery intermittent mechanism. One terminal of the additional relay 5 is connected to the lithium ion battery 21 , and the other terminal of the additional relay 5 is connected to the power supply line 3 on the second load circuit 2 side via the current sensor 61 . In this embodiment, a normally closed type relay is used as the additional relay 5 . Like the main relay 4, the additional relay 5 may be, for example, a mechanical relay or a semiconductor relay. In this embodiment, as the additional relay 5, a mechanical relay will be described as an example.

An opening/closing control signal is input to the additional relay 5 from the controller 6, and the additional relay 5 is turned on or off according to the input opening/closing control signal. In addition to the open/close control signal, the additional relay 5 is supplied with a continuity maintenance command or a release command from the controller 6 . Once the continuity maintenance command is input, the additional relay 5 continues to maintain the ON state until the cancellation command is input, regardless of whether the opening/closing control signal is input. When a cancellation command is input after the conduction maintenance command is input, the additional relay 5 cancels the maintenance of the ON state and turns ON or OFF again according to the opening/closing control signal. When the additional relay 5 is a mechanical relay as in the present embodiment, the opening/closing control signal is, for example, a voltage application signal for generating a magnetic field to switch from off to on, or a voltage application signal for extinguishing the magnetic field and switching from on to off. It is a voltage stop signal. The continuity maintenance command is, for example, a forced voltage application signal for maintaining the ON state by continuously generating the magnetic field. In the following description, "on (on state) of the additional relay 5" means that the terminals of the additional relay 5 are electrically connected, and "off (off state) of the additional relay 5" means that the additional relay 5 is turned off (off state). 5 is insulated (disconnected) between terminals.

Further, in the present embodiment, the conduction or interruption of the additional relay 5 by the opening/closing control signal will be described as an example. may be performed by the method of For example, as a power supply system, a configuration in which a DCDC converter is provided between the lithium ion battery 21 and the additional relay 5 and the voltage of the lithium ion battery 21 is stepped up by the DCDC converter and output is also conceivable. In this configuration, even the DCDC converter alone can function as a relay, so the lithium ion battery 21 and the additional relay 5 may be electrically connected or disconnected by controlling the DCDC converter.

Next, the controller 6 will be explained. The controller 6 is a computer comprising hardware and software, and is an electronic control unit (ECU) having a memory that stores a program and a CPU that executes the program stored in this memory. . As the operating circuit, an MPU, DSP, ASIC, FPGA, or the like can be used instead of or together with the CPU. The controller 6 implements various functions by having the CPU execute programs stored in the ROM. Functions realized by the controller 6 will be described later.

As shown in FIG. 1, the controller 6 includes a current sensor 61, an automatic operation mode switch 62, a first voltage sensor 63, a second voltage sensor 64, a battery voltage sensor 65, a brake switch 66, a torque sensor 67, and an ignition switch 68. , the vehicle speed sensor 69 and the advanced driving support system 70 . Also, the controller 6 executes processing based on the input information, and outputs an open/close control signal, continuity maintenance command, or cancellation command to the main relay 4 and/or the additional relay 5 based on the execution result. Further, the controller 6 executes processing based on the input information, and outputs control commands to the display device 71 and buzzer 72 based on the execution result.

A current sensor 61 is provided between the main relay 4 and the additional relay 5 and detects the direction of the current to the lithium ion battery 21 . A detection result by the current sensor 61 is output to the controller 6 .

The automatic driving mode switch 62 is a switch that can be operated by the driver and is a switch for starting the automatic driving mode. When the driving mode of the vehicle is the normal driving mode, the driver turns on the automatic driving mode switch 62 to start the automatic driving mode. When the driving mode of the vehicle is the automatic driving mode, the normal driving mode is started when the driver turns off the automatic driving mode switch 62 . The form, installation position, and the like of the automatic driving mode switch 62 are not particularly limited, but an example of the automatic driving mode switch 62 is a button that is provided on the steering wheel and can be operated by the driver. Information on the operation of the automatic driving mode switch 62 by the driver is output to the controller 6 and the advanced driving support system 70 .

The first voltage sensor 63 detects the circuit voltage of the first load circuit 1 . The circuit voltage of the first load circuit 1 is the voltage of the power supply line 3 on the first load circuit 1 side. The first voltage sensor 63 is connected in parallel to each component included in the first load circuit 1, for example. A detection result by the first voltage sensor 63 is output to the controller 6 . Moreover, when a semiconductor relay having a self-interrupting/connecting function is used as the main relay 4 as in the present embodiment, the detection result by the first voltage sensor 63 is also output to the main relay 4 .

A second voltage sensor 64 detects the circuit voltage of the second load circuit 2 . The circuit voltage of the second load circuit 2 is the voltage of the power supply line 3 on the side of the second load circuit 2 . The second voltage sensor 64 is connected in parallel to each load included in the second load circuit 2, for example. A detection result by the second voltage sensor 64 is output to the controller 6 . Moreover, when a semiconductor relay having a self-interrupting/connecting function is used as the main relay 4 as in the present embodiment, the detection result by the second voltage sensor 64 is also output to the main relay 4 .

A battery voltage sensor 65 detects the battery voltage of the lithium ion battery 21 . A detection result by the battery voltage sensor 65 is output to the controller 6 . A brake switch 66 detects a brake operation by the driver. Information on the brake operation by the driver detected by the brake switch 66 is output to the controller 6 . The torque sensor 67 detects the steering torque applied to the steering shaft by steering operation by the driver. Information on the steering operation by the driver detected by the torque sensor 67 is output to the controller 6 .

The ignition switch 68 is a start switch (also called a main power switch) for starting the vehicle. In the case of a vehicle using an engine as a drive source as in this embodiment, when the ignition switch 68 is turned on, the engine starts and the vehicle becomes ready to run. On the other hand, when the ignition switch 68 is turned off, the engine is stopped and the vehicle is parked. Examples of the method of the ignition switch 68 include an engine key method in which the vehicle is started by an occupant turning a vehicle key inserted in a keyhole, and a push start method in which the vehicle is started by the occupant pressing a button shape. . The ignition switch 68 has a display for activating the driving source of the vehicle (ON display) or a display for stopping the driving source of the vehicle (OFF display). A display (ACC display) for energizing an electrical system such as an audio system, a display (START display) for driving the starter motor 13 to start the air conditioning system, and the like may be provided. Information on the operation of the ignition switch 68 by the driver is output to the controller 6 . A vehicle speed sensor 69 detects the vehicle speed. A detection result by the vehicle speed sensor 69 is output to the controller 6 .

The advanced driving support system 70 is a system for assisting the driver in driving by performing automatic brake control, auto-cruise control, lane keep control, and the like. A result of processing by the advanced driving support system 70 is output to the controller 6 . The display device 71 displays a warning display to inform the driver that some kind of abnormality has occurred in the automatic driving mode and to prompt the driver to perform a driving operation. The buzzer 72 outputs a warning sound to inform the driver that some kind of abnormality has occurred in the automatic driving mode and prompt the driver to perform driving operation.

Next, functions realized by the controller 6 will be described with reference to FIGS. 2A and 2B. 2A and 2B are flow charts showing an example of the procedure of the control method of the power supply system 100 executed by the controller 6 shown in FIG. 1. FIG. The procedure of this control method is started from the state where the ignition switch 68 is turned off (the vehicle is parked).

In step S1, the controller 6 outputs a close control signal (hereinafter simply referred to as a closed control signal) for turning on the relay to the main relay 4, and adds an open control signal (hereinafter simply referred to as an open control signal) for turning off the relay. Output to relay 5. When the vehicle is parked and the additional relay 5 and each load included in the second load circuit 2 are electrically connected, the dark current of the load discharges the lithium ion battery 21 . By the processing in this step, the connection between the additional relay 5 and each load included in the second load circuit 2 is cut off, so that the discharge of the lithium ion battery 21 due to the dark current of the load can be prevented.

Here, the processing of the controller 6 performed before outputting the open control signal to the main relay 4 or the additional relay 5 will be described with reference to the flow charts shown in FIGS. 2A and 2B. In this embodiment, the controller 6 performs opening/closing control of the main relay 4 and the additional relay 5 so that at least one of the main relay 4 and the additional relay 5 is turned on. Specifically, the controller 6 acquires information about the state of the main relay 4 and the state of the additional relay 5, and does not output the open control signal to the main relay 4 when the additional relay 5 is in the OFF state. is off, it does not output the open control signal to the additional relay 5 . This processing is to prevent both the main relay 4 and the additional relay 5 from being turned off and the power supply to each load included in the second load circuit from being interrupted.

Information about the states of the main relay 4 and the additional relay 5 includes, for example, the detection result of the current sensor 61, and the controller 6 determines the states of the main relay 4 and the additional relay 5 from the detection result of the current sensor 61. .

For example, when the current direction detected by the current sensor 61 (hereinafter referred to as the detected current direction) is toward the lithium ion battery 21, the controller 6 determines that both the main relay 4 and the additional relay 5 are on. Further, the controller 6 may determine that both the main relay 4 and the additional relay 5 are on when the detected current direction is from the lithium ion battery 21 to the first load circuit 1 . When the detected current direction is from the lithium ion battery 21 to each load included in the second load circuit 2, the controller 6 determines that the main relay 4 is off and the additional relay 5 is on. Further, the controller 6 determines that at least the additional relay 5 is in the OFF state when the direction of the detected current is neither direction. Note that the determination method using the detection result of the current sensor 61 is merely an example. For example, when a signal indicating an ON state or an OFF state can be obtained from each of the main relay 4 and the additional relay 5, the controller 6 controls the main relay 4 and the additional relay 5 based on the signals obtained from the main relay 4 and the additional relay 5. 5 states may be determined. In the description of the subsequent steps, when the controller 6 outputs the open control signal to the main relay 4 or the additional relay 5, it is assumed that the controller 6 executes the above-described processing before outputting the open control signal.

Returning to FIG. 2A, in step S2, the controller 6 determines whether or not the vehicle is parked based on the operation information from the ignition switch 68. FIG. When the controller 6 receives an ON signal from the ignition switch 68 indicating that the driving source of the vehicle is activated, the controller 6 determines that the vehicle is not in the parked state because the vehicle has changed from the parked state to the drivable state. . On the other hand, when the controller 6 receives an OFF signal from the ignition switch 68 indicating that the drive source of the vehicle is stopped, the controller 6 determines that the vehicle is parked. If the controller 6 makes a negative determination, the process proceeds to step S3. If the controller 6 makes an affirmative determination, it waits in step S2 until a negative determination is made, that is, until the ignition switch 68 is turned on and the vehicle becomes ready to run. Since the additional relay 5 is turned off by the process of step S1 while the process of the controller 6 is waiting in step S2, it is possible to prevent the lithium ion battery 21 from discharging due to the dark current of the load. The method of determining whether or not the vehicle is parked is not limited to the determination method based on the operation information from the ignition switch 68, and other determination methods known at the time of filing the present application may be used.

In step S<b>3 , the controller 6 outputs a close control signal to the main relay 4 and an open control signal to the additional relay 5 . Note that the controller 6 does not need to output the close control signal to the main relay 4 because the processing for the main relay 4 is the same as in step S<b>1 .

Further, in step S3, when the additional relay 5 is in the off state, the controller 6 may switch the additional relay 5 from off to on at the timing when the vehicle speed equal to or higher than the predetermined speed is detected. For example, when the controller 6 detects that the vehicle speed is several km/h or more from the detection result from the vehicle speed sensor 69, the controller 6 may output the opening control signal to the additional relay 5 at the timing of detection. good. The predetermined speed is a predetermined speed.

In step S4, the controller 6 determines whether the driving mode of the vehicle is the automatic driving mode or the normal driving mode. For example, when the controller 6 acquires an ON signal from the automatic driving mode switch 62, the driving mode of the vehicle may be determined as the automatic driving mode. Further, the controller 6 may determine that the driving mode of the vehicle is the automatic driving mode when detecting the output of the control signal for actuating each load included in the second load circuit 2 . Further, when the controller 6 acquires a signal indicating that each load included in the second load circuit 2 is in operation, the controller 6 may determine that the driving mode of the vehicle is the automatic driving mode. The controller 6 determines that the driving mode of the vehicle is the automatic driving mode when any one of the above examples applies. On the other hand, the controller 6 determines that the driving mode of the vehicle is the normal driving mode when none of the above examples apply. When the driving mode of the vehicle is determined to be the automatic driving mode, the process proceeds to step S5, and when the driving mode of the vehicle is determined to be the normal driving mode, the process proceeds to step S12 shown in FIG. 2B.

As a method for determining that the driving mode of the vehicle is the normal driving mode, the method of determining that the vehicle is not in the automatic driving mode has been described as an example. may For example, when the controller 6 acquires an OFF signal from the automatic driving mode switch 62, the driving mode of the vehicle may be determined to be the normal driving mode. Further, the controller 6 may determine that the driving mode of the vehicle is the normal driving mode when receiving a brake operation signal by the driver from the brake switch 66 . Further, when the controller 6 acquires a steering operation signal by the driver from the torque sensor 67, the controller 6 may determine that the driving mode of the vehicle is the normal driving mode. The controller 6 may determine that the driving mode of the vehicle is the normal driving mode when any one of the above examples applies. Further, the controller 6 acquires a driving mode signal indicating the driving mode of the vehicle from the advanced driving support system 70, and determines whether the driving mode of the vehicle is the automatic driving mode or the normal driving mode based on the driving mode signal. may For example, when the advanced driving support system 70 acquires an ON signal from the automatic driving mode switch 62, it determines that the driving mode of the vehicle is the automatic driving mode. Further, when the advanced driving support system 70 acquires the OFF signal from the automatic driving mode switch 62, the driving mode of the vehicle is determined to be the normal driving mode. The controller 6 may determine whether the driving mode of the vehicle is the automatic driving mode or the normal driving mode according to the driving mode signal obtained from the advanced driving assistance system 70 .

In step S<b>5 , the controller 6 outputs a cancellation command to the main relay 4 and outputs a continuity maintenance command to the additional relay 5 . As explained for the additional relay 5, the continuity maintenance command is a command that has force to keep the ON state. Therefore, for example, even if the opening/closing control signal is input to the additional relay 5 for some reason, if the conduction maintenance command is input to the additional relay 5 before that, the additional relay 5 will not open/close according to the input opening/closing control signal. It ignores the control signal and forcibly maintains the ON state by the continuity maintenance command. If the driving mode of the vehicle is determined to be the automatic driving mode, the controller 6 causes the additional relay 5 to remain on in this step. Further, the controller 6 outputs a conduction maintenance command to the additional relay 5 at predetermined intervals (for example, every 100 ms) until the release command is output to the additional relay 5 . Thereby, it is possible to further reduce the possibility that the additional relay 5 is turned off in the automatic operation mode. On the other hand, the controller 6 outputs a release command to the main relay 4 so that the main relay 4 can be controlled by the open/close control signal. As in this embodiment, when the main relay 4 is a semiconductor relay having a self-shutoff/connection function, the self-shutdown/connection function of the main relay 4 is activated by a release command.

In step S<b>6 , the controller 6 determines whether or not a voltage abnormality has occurred in the power supply system 100 based on the circuit voltage of the second load circuit 2 . Based on the detection result of the second voltage sensor 64, the controller 6 determines whether or not the circuit voltage on the additional battery side (the circuit voltage of the second load circuit 2) is outside the predetermined voltage range. The predetermined voltage range is a range whose unit is voltage and is a predetermined range. The upper limit value of the predetermined voltage range is a voltage value determined to prevent overvoltage to each load included in the second load circuit 2, and the lower limit value of the predetermined range is included in the second load circuit 2. It is the voltage value determined to operate each load according to specifications. If the controller 6 makes a negative determination, that is, if it determines that the voltage abnormality has not occurred in the power supply system 100, the process proceeds to step S7. On the other hand, if the controller 6 makes an affirmative determination, that is, if it determines that the power supply system 100 has a voltage abnormality, the process proceeds to step S8.

In step S<b>7 , the controller 6 outputs a close control signal to the main relay 4 and the additional relay 5 . Note that in the example of FIG. 2A, step S7 is shown for comparison with step S8. However, since the main relay 4 is turned on by the process of step S1 or step S3, and the additional relay 5 is turned on by the process of step S5, the controller 6 omits the process of step S7. good too. When the process in step S7 is completed, the process returns to step S4, and the vehicle driving mode is determined again. When the vehicle can run in the automatic driving mode and no voltage abnormality occurs in the power supply system 100, the processes of steps S4 to S7 are repeatedly executed, so both the main relay 4 and the additional relay 5 remain on. do.

If the determination in step S6 is affirmative, the process proceeds to step S8. In step S<b>8 , the controller 6 outputs an open control signal to the main relay 4 and outputs a close control signal to the additional relay 5 . In the automatic operation mode, the main relay 4 switches from on to off when the circuit voltage of the second load circuit 2 goes out of the predetermined voltage range. On the other hand, in the automatic operation mode, the additional relay 5 operates independently of the circuit voltage of the second load circuit 2 by the process of step S5 even if the circuit voltage of the second load circuit 2 is outside the predetermined voltage range. , remain on. The switching of the main relay 4 cuts off the power supply from the first load circuit 1 side to each load included in the second load circuit 2 . However, since the additional relay 5 maintains the ON state, power is supplied from the lithium ion battery 21 to each load included in the second load circuit 2 . That is, in the automatic operation mode, each load included in the second load circuit 2 can continue to operate with the power from the lithium ion battery 21 even if the power supply from the first load circuit 1 side is interrupted. Note that the controller 6 does not need to output the close control signal to the additional relay 5 because the continuity maintenance command has been input to the additional relay 5 by the process of step S5.

Further, when the main relay 4 is a semiconductor relay having a self-interruption/connection function as in the present embodiment, switching from ON to OFF of the main relay 4 may be performed by the self-interruption/connection function of the main relay 4. . For example, the main relay 4 detects that the circuit voltage of the second load circuit 2 (the terminal voltage of the main relay 4 connected to the second load circuit 2) is outside the predetermined voltage range based on the detection result from the second voltage sensor 64. may be switched from on to off by a self-shutdown/connect function upon detecting that Since the switching of the main relay 4 from on to off by the self-interruption/connection function is faster than the open control signal is transmitted from the controller 6 to the main relay 4, the circuit voltage of the second load circuit 2 is within the predetermined voltage range. It is possible to shorten the period of time outside, and to protect each load included in the second load circuit 2 more.

In step S9, the controller 6 outputs a warning display signal to the display device 71 to inform the driver that an abnormality has occurred in the automatic driving mode. The controller 6 may also output a warning sound signal to the buzzer 72 . The controller 6 may also output a warning display signal to the display device 71 and a warning sound signal to the buzzer 72 . The processing in this step prompts the driver to shift from the automatic driving mode to the normal driving mode. In other words, this step is a step for requesting the driver to regain control of the driving that was being performed by the driving assistance device. Since the additional relay 5 is kept on by the processing in step S5, each load included in the second load circuit 2 is operated by the electric power from the lithium ion battery 21, and the autonomous driving of the vehicle in the automatic driving mode is performed. continuing.

Since operation intervention by the driver is a condition for canceling the automatic driving mode, when the driver performs driving operations such as brake operation, accelerator operation, and steering operation, in step S10, the controller 6 changes the driving mode of the vehicle to automatic. It is determined that the operating mode has shifted to the normal operating mode. For example, when the controller 6 acquires the signal of the driver's braking operation from the brake switch 66 or the signal of the steering operation by the driver from the torque sensor 67, the automatic driving mode is canceled and the vehicle is driven. It is determined that the mode has changed to the normal operation mode.

In step S<b>11 , the controller 6 outputs a close control signal to the main relay 4 and the additional relay 5 . The controller 6 does not need to output the close control signal to the additional relay 5 because the additional relay 5 has received the conduction maintenance command by the process of step S5. Further, the controller 6 may output to the additional relay 5 a cancellation command in response to the continuity maintenance command output in step S5. After completing the process in step S11, the controller 6 terminates the processes shown in FIGS. 2A and 2B.

When it is determined in step S4 that the driving mode of the vehicle is the normal driving mode, the process proceeds to step S12 shown in FIG. 2B. At step S<b>12 , the controller 6 outputs a conduction maintenance command to the main relay 4 and outputs a cancellation command to the additional relay 5 . As explained with respect to the main relay 4, the continuity maintenance command is a command having force to maintain the ON state. For this reason, for example, even if the switching control signal is input to the main relay 4 for some reason, if the continuity maintaining command is input to the main relay 4 before that, the main relay 4 does not open or close according to the input switching control signal. It ignores the control signal and forcibly maintains the ON state by the continuity maintenance command. When the driving mode of the vehicle is determined to be the normal driving mode, the controller 6 keeps the main relay 4 on in this step. Further, the controller 6 outputs a continuity maintenance command to the main relay 4 at predetermined intervals (for example, every 100 ms) until the release command is output to the main relay 4 . This can further reduce the possibility that the main relay 4 is turned off in the normal operation mode. In the case where the main relay 4 is a semiconductor relay having a self-shutoff/connection function as in this embodiment, this step disables the self-shutoff/connection function of the main relay 4, so that the main relay 4 does not self-shutdown/connect. You can prevent a feature from switching from on to off. On the other hand, the controller 6 outputs a release command to the additional relay 5 to make the additional relay 5 controllable by the open/close control signal.

In step S<b>13 , the controller 6 determines whether or not a voltage abnormality has occurred in the power supply system 100 based on the circuit voltage of the second load circuit 2 . Since step S13 corresponds to step S6, the description of step S6 is used for the description of step S13. If the controller 6 makes a negative determination, that is, if it determines that the voltage abnormality has not occurred in the power supply system 100, the process returns to step S4 shown in FIG. 2A. On the other hand, if the controller 6 makes an affirmative determination, that is, if it determines that the voltage abnormality has occurred in the power supply system 100, the process proceeds to step S14.

If a negative determination is made in step S13, the process returns to step S4 to determine the driving mode of the vehicle again. If no voltage abnormality occurs in the power supply system 100 when the vehicle can run in the normal operation mode, the processes of steps S4, S12, and S13 are repeatedly executed. stay on. If the ignition switch 68 is turned off while the processes of steps S4, S12, and S13 are being repeatedly executed, the controller 6 determines that the vehicle has transitioned from a state in which it can travel to a state in which it is parked. Then, the close control signal is output to the main relay 4 and the open control signal is output to the additional relay 5, as in the process of step S1. The additional relay 5 is switched from on to off while the main relay 4 remains on.

Here, from the state where the first load circuit 1 and the second load circuit 2 are electrically connected and current is flowing from the first load circuit 1 side to the second load circuit side, the additional relay 5 is turned off from on. States of the power supply system 100 that may occur when switching are described. For example, when the processes of steps S4, S12, and S13 are repeatedly executed, both the main relay 4 and the additional relay 5 are kept on, so that the lithium ion battery 21 is supplied with A current is input from the first load circuit 1 side. When the additional relay 5 is a mechanical relay as in this embodiment, when the additional relay 5 is switched from on to off, a back electromotive force is generated in the additional relay 5 to maintain the current flowing through the coil of the mechanical relay. The back electromotive force becomes a surge voltage that occurs momentarily, and is input to the main relay 4 via the power supply line 3 . If the main relay 4 is a semiconductor relay having a self-interruption/connection function as in this embodiment, the main relay 4 may switch from ON to OFF due to the self-interruption/connection function upon detection of a surge voltage. However, since the main relay 4 maintains the ON state with the self-interruption/connection function disabled by the processing in step S12, the surge voltage is input to the main relay 4 by switching the additional relay 5 from ON to OFF. Even if this is done, it is possible to prevent the main relay 4 from being switched from ON to OFF. As a result, each load included in the second load circuit 2 can continue to be supplied with power from the first load circuit 1 side, and the circuit voltage of the second load circuit 2 can be maintained.

Returning to FIG. 2B, if the determination in step S13 is affirmative, the process proceeds to step S14. At step S<b>14 , the controller 6 outputs a close control signal to the main relay 4 and an open control signal to the additional relay 5 . The additional relay 5 is switched from on to off when the circuit voltage of the second load circuit 2 is out of the predetermined voltage range in the normal operation mode. On the other hand, in the normal operation mode, the main relay 4 is irrelevant to the circuit voltage of the second load circuit 2 even if the circuit voltage of the second load circuit 2 is outside the predetermined voltage range by the processing in step S12. remain on. As described above, since the additional relay 5 is switched from on to off while the main relay 4 is on, there is a risk that a surge voltage may occur due to the switching of the additional relay 5 in this step as well. It remains on by processing. Note that the controller 6 does not need to output the close control signal to the main relay 4 because the main relay 4 has been input with the conduction maintenance command by the process of step S<b>12 .

In step S<b>15 , the controller 6 determines whether or not the voltage abnormality that occurred in step S<b>13 continues based on the circuit voltage of the second load circuit 2 . Since step S15 corresponds to step S6 and step S13, the description of step S6 and step S13 is used for the description of step S15. When the controller 6 makes a negative determination, that is, when it determines that the power supply system 100 does not have a voltage abnormality, the process proceeds to step S11 shown in FIG. 2A. On the other hand, if the controller 6 makes an affirmative determination, that is, if it determines that the voltage abnormality of the power supply system 100 continues to occur, the process waits in step S15 until an affirmative determination is made.

If the ignition switch 68 is turned off while waiting in step S15, the controller 6 determines that the vehicle has transitioned from the drivable state to the parked state. to the main relay 4 and an open control signal to the additional relay 5 . Further, the controller 6 may output to the main relay 4 a cancellation command in response to the continuity maintenance command output in step S12.

If a negative determination is made in step S15, the process proceeds to step S11 shown in FIG. The controller 6 does not need to output the close control signal to the main relay 4 because the main relay 4 has received the continuity maintenance command by the process of step S<b>12 . Further, the controller 6 may output to the main relay 4 a cancellation command in response to the continuity maintenance command output in step S12. After completing the process in step S11, the controller 6 terminates the processes shown in FIGS. 2A and 2B.

When the process proceeds from step S15 to step S11 and then the ignition switch 68 is turned off, the controller 6 determines that the vehicle has transitioned from the drivable state to the parked state. A control signal is output to the main relay 4 and an open control signal is output to the additional relay 5 . Further, the controller 6 may output to the main relay 4 a cancellation command in response to the continuity maintenance command output in step S12.

As described above, the power supply system 100 according to the present embodiment is a power supply system mounted on a vehicle having a normal operation mode and an automatic operation mode operated by the driver, and includes the first load circuit 1 and the second load circuit 2. , a main relay 4 , an additional relay 5 and a controller 6 . The first load circuit 1 operates with power from a lead battery 11 or an alternator 14, and is connected to a load actuator 12 and a starter motor 13 necessary for continuing the normal operation mode. The second load circuit 2 operates with power from the lead battery 11 or the lithium ion battery 21, and is connected to an EPS actuator 22, an ABS actuator 23, and an ADAS actuator 24 that are required to continue the automatic operation mode. The main relay 4 is provided on the power supply line 3 that electrically connects the first load circuit 1 and the second load circuit 2 , and connects or disconnects the first load circuit 1 and the second load circuit 2 . The additional relay 5 connects or disconnects the lithium ion battery 21 and each load included in the second load circuit 2 . In this embodiment, when the controller 6 determines that the driving mode of the vehicle is the normal driving mode (determines the normal driving mode in step S4 of FIG. 2A), the circuit voltage of the second load circuit 2 is outside the predetermined voltage range. Then (YES in step S13 of FIG. 2B), the additional relay 5 is switched from ON to OFF (step S14 of FIG. 2B). On the other hand, when the controller 6 determines that the driving mode of the vehicle is the automatic driving mode (determines the automatic driving mode in step S4 of FIG. 2A), regardless of the circuit voltage of the second load circuit 2, the additional relay 5 is turned on. The state is maintained (steps S7 and S8 in FIG. 2A).

Since the additional relay 5 can disconnect between the lithium ion battery 21 and each load included in the second load circuit 2, the lithium ion battery 21 is discharged by the dark current of the load when the vehicle is parked. It is possible to prevent the remaining battery level of the As a result, even if the main relay 4 is turned off when the vehicle can run in the automatic operation mode, the lithium-ion battery 21 continues autonomous driving with respect to each load included in the second load circuit 2. can supply power for In addition, it is possible to prevent the lithium ion battery 21 from continuing to discharge in a state of being equal to or lower than the end-of-discharge voltage, that is, over-discharging of the lithium ion battery 21 . As a result, the deterioration of the lithium ion battery 21 can be alleviated, and the battery life of the lithium ion battery 21 can be extended. In addition, by providing the additional relay 5, in the automatic operation mode, the additional relay 5 is suddenly turned off for some reason, and the lithium-ion battery 21 and the second load circuit 2, which are backup power supply sources, are turned off. There is concern that there will be interruptions between each load that is connected. However, in the power supply system 100 and the control method of the power supply system 100 of the present embodiment, since the additional relay 5 maintains the ON state in the automatic operation mode, the lithium ion battery 21 and each load included in the second load circuit 2 You can prevent interruptions. That is, according to the power supply system 100 and the control method of the power supply system 100 of the present embodiment, it is possible to prevent the remaining battery level of the lithium ion battery 21 from decreasing due to dark current discharge and to ensure backup operation by the lithium ion battery 21 .

Further, in the present embodiment, when the controller 6 determines that the driving mode of the vehicle is the automatic driving mode (determines the automatic driving mode in step S4 of FIG. 2A), the controller 6 outputs to the additional relay 5 a conduction maintenance command to maintain the ON state. (Step S5 in FIG. 2A). As a result, in the automatic operation mode, the ON state of the additional relay 5 can be maintained, so that the continuity state is maintained between the lithium ion battery 21 and the second load circuit 2 . As a result, even if the main relay 4 is turned off in the automatic driving mode, the loads included in the second load circuit 2 allow the vehicle to continue autonomous driving.

Further, in the present embodiment, the conduction maintenance command output to the additional relay 5 maintains the ON state of the additional relay 5 regardless of the circuit voltage of the second load circuit 2 and the switching of the main relay 4 from ON to OFF. This is a command to make the device rotate (step S5 in FIG. 2A). As a result, even if a signal corresponding to the open control signal is input to the additional relay 5 due to the circuit voltage of the second load circuit 2 or the switching of the main relay 4 from on to off, the additional relay 5 is turned on. can be maintained.

Further, in the present embodiment, when the controller 6 determines that the driving mode of the vehicle is the normal driving mode (determines the normal driving mode in step S4 of FIG. 2A), the controller 6 sends a cancellation command to cancel the conduction maintenance command to the additional relay 5. Output (step S12 in FIG. 2B). As a result, in the normal operation mode, the on/off of the additional relay 5 can be controlled by the open/close control signal. As a result, as in the present embodiment, the controller 6 can turn off the additional relay 5 when it is determined that the circuit voltage of the second load circuit 2 is outside the predetermined voltage range in the normal operation mode (Fig. 2B step S14).

Further, in this embodiment, the controller 6 acquires information about the state of the main relay 4 and the state of the additional relay 5, and when the additional relay 5 is in the OFF state, does not output the open control signal to the main relay 4, 4 is off, it does not output the open control signal to the additional relay 5 . As a result, it is possible to prevent both the main relay 4 and the additional relay 5 from being turned off and the power supply to each load included in the second load circuit 2 from being interrupted. In addition, only by monitoring the state of the main relay 4 and the state of the additional relay 5 without requiring complicated processing, it is possible to prevent the power supply to the second load circuit 2 side from being interrupted. It is possible to reduce the load and improve the processing speed.

Further, in the present embodiment, the controller 6 determines whether or not the vehicle is parked, and turns off the additional relay 5 when determining that the vehicle is parked. As a result, when the vehicle is parked, the lithium-ion battery 21 is disconnected from the loads included in the second load circuit 2, so that the lithium-ion battery 21 can be prevented from being discharged due to the dark current of the load. . Since the remaining battery level of the lithium ion battery 21 can be prevented from decreasing due to dark current discharge, each load included in the second load circuit 2 can operate according to specifications with the power from the lithium ion battery 21 . Also, the output voltage of the lithium-ion battery 21 can be maintained at a voltage for each load to operate according to specifications.

In the present embodiment, when the additional relay 5 is in the off state, the controller 6 switches the additional relay 5 from off to on at the timing when the vehicle speed equal to or higher than the predetermined speed is detected (step S3 in FIG. 2A). As a result, for example, the lithium ion battery 21 and each load included in the second load circuit 2 can be brought into conduction in accordance with the start timing of the vehicle.

Further, in this embodiment, the main relay 4 is a normally open type relay, and the additional relay 5 is a normally closed type relay. As a result, the main relay 4 can be turned off in advance before the main relay 4 is electrically connected to the lead battery 11 and the alternator 14, such as when the vehicle is manufactured. Similarly, the additional relay 5 can be pre-activated before the additional relay 5 electrically connects with the lithium-ion battery 21 . The state of each relay can be controlled in advance without requiring an open/close control signal.

It should be noted that the embodiments described above are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiments is meant to include all design changes and equivalents that fall within the technical scope of the present invention.

In the embodiment described above, in the flowchart of FIG. Additional relays 5 may be turned off depending on the amount. When the controller 6 determines that the driving mode of the vehicle is the automatic driving mode, and the circuit voltage of the second load circuit 2 is outside the predetermined voltage range, the controller 6 switches the main relay 4 from ON to OFF (step S8 in FIG. 2A). , After the operation mode of the vehicle shifts from the automatic operation mode to the normal operation mode (step S10 in FIG. 2A), if the remaining battery amount of the lithium ion battery 21 is less than a predetermined remaining amount, the additional relay 5 is switched from ON to OFF. may For the calculation of the remaining battery capacity of the lithium ion battery 21 performed by the controller 6, a known calculation method known at the time of filing of the present application can be used. Since overdischarge of the lithium-ion battery 21 can be prevented, deterioration of the lithium-ion battery 21 can be alleviated, and battery life of the lithium-ion battery 21 can be extended.

Further, in the above-described embodiment, the lead battery 11 is used as the main battery, but a secondary battery such as a lithium ion battery or a nickel metal hydride battery may be used as the main battery. Further, in the above-described embodiment, the case where the lithium ion battery 21 is used as the additional battery has been shown, but as the additional battery, a plurality of batteries may be used, a capacitor and a DCDC converter may be combined, or A nickel metal hydride battery may also be used. Further, in the above-described embodiment, the alternator 14 is used as the generator of the first load circuit 1, but a generator, motor generator, or the like may be used as the generator of the first load circuit. In the above-described embodiment, the EPS actuator 22, the ABS actuator 23, and the ADAS actuator 24 are used as the loads included in the second load circuit 2, but the load necessary for continuing the automatic operation mode is the vehicle may be changed according to the specifications of the driving support device. In the above-described embodiment, the additional relay 5 and the lithium ion battery 21 are not included in the second load circuit 2, but the second load circuit 2 may include the additional relay 5 and the lithium ion battery 21. good. In the above-described embodiment, the main relay 4 is a semiconductor relay having a self-interruption/connection function. may be used. Further, in the above-described embodiment, a mechanical relay is used as the additional relay 5 , but a semiconductor relay may be used as the additional relay 5 .

Further, in the above-described embodiment, the case where the power supply system and the control method of the power supply system according to the present invention are applied to a vehicle having a hands-off mode with driving assistance level 2 has been described as an example. However, the power supply system and power supply system control method according to the present invention can also be applied to a vehicle with driving assistance level 3.

Further, in the above-described embodiment, the case where the power supply system and the power supply system control method according to the present invention are applied to a vehicle having an engine as a drive source (engine automobile) has been described as an example. However, the power supply system and the control method of the power supply system according to the present invention are applicable to a vehicle having a battery as a drive source (electric vehicle), a vehicle having an engine and a battery as a drive source (hybrid vehicle), and a vehicle having a fuel cell as a drive source (fuel cell). automobiles). In short, the first load circuit operated by the power from the main battery and connected with the first load required to continue the normal operation mode, and the power from the additional battery operated by the first load circuit required to continue the automatic operation mode. A second load circuit to which two loads are connected is provided on a feeder line that electrically connects the first load and the second load, and a first load circuit that conducts or cuts off between the first load circuit and the second load circuit is provided. The present invention can be applied to a vehicle equipped with a power supply system having a relay, a second relay that connects or disconnects an additional battery and a second load, and a controller that determines the operation mode of the vehicle.

Further, in the above-described embodiment, the control procedure of proceeding to step S11 after the driving mode of the vehicle shifts from the automatic driving mode to the normal driving mode in step S10 of FIG. 2A has been described as an example. However, after the process of step S10, the process may proceed to step S12 shown in FIG. 2B, as in the case where the vehicle driving mode is determined to be the normal driving mode in step S4.

In the above-described embodiment, the case where it is determined whether or not the circuit voltage of the second load circuit 2 is outside the predetermined voltage range has been described in step S6 of FIG. 2A and steps S13 and S15 of FIG. 2B. However, since the first load circuit 1 and the second load circuit 2 are electrically connected by the main relay 4 in any step, the controller 6 ensures that the circuit voltage of the first load circuit 1 is within the predetermined voltage range in each step. You may determine whether it is outside. In the above-described embodiment, the case where the additional relay 5 is switched from ON to OFF by the controller 6 when the circuit voltage of the second load circuit 2 is outside the predetermined voltage range in step S13 of FIG. 2B has been described. However, when the driving mode of the vehicle is the normal driving mode, the condition for switching the additional relay 5 from ON to OFF may be a case where the current flowing through the additional relay 5 is equal to or greater than a predetermined current threshold. For example, when the driving mode of the vehicle is determined to be the normal driving mode (determined to be the normal driving mode in step S4 of FIG. 2A), the controller 6 determines the current flowing through the additional relay 5 based on the detection result from the current sensor 61 and the Compare with a predetermined current threshold. The direction of the current flowing through the additional relay 5 is not particularly limited, and the controller 6 compares the absolute value of the current flowing through the additional relay 5 with a predetermined current threshold. The predetermined current threshold is a current threshold determined based on the contact life of the additional relay 5 in units of current. The controller 6 outputs an open control signal to the additional relay 5 when the absolute value of the current flowing through the additional relay 5 is equal to or greater than a predetermined current threshold. As a result, when an excessive current flows through the additional relay 5 in the normal operation mode, by switching the additional relay 5 from ON to OFF, the wear speed of the contacts of the additional relay 5 can be reduced.

In the above-described embodiment, as a condition for the controller 6 to turn off the main relay 4 in step S6 of FIG. 2A, the condition that the circuit voltage of the second load circuit 2 is outside the predetermined voltage range has been described as an example. However, in step S6, the controller 6 determines if the circuit voltage of the second load circuit 2 is lower than the lower limit value of the predetermined voltage range, or if the circuit voltage of the second load circuit 2 is lower than the upper limit value of the predetermined voltage range. is also high, the main relay 4 may be turned off. Similarly, in the above-described embodiment, as a condition for the controller 6 to turn off the additional relay 5 in step S13 of FIG. 2B, the circuit voltage of the second load circuit 2 is outside the predetermined voltage range. bottom. However, in step S13, the controller 6 determines if the circuit voltage of the second load circuit 2 is lower than the lower limit value of the predetermined voltage range, or if the circuit voltage of the second load circuit 2 is lower than the upper limit value of the predetermined voltage range. is also high, the additional relay 5 may be turned off.

Reference Signs List 1 First load circuit 11 Lead battery 12 Load actuator 13 Starter motor 14 Alternator 2 Second load circuit 21 Lithium-ion battery 22 EPS actuator 23 ABS actuator 24 ADAS actuator 3 Feed line 4 Main relay 5 Additional relay 6 Controller 61 Current sensor 62 Automatic operation mode switch 63 First voltage sensor 64 Second voltage sensor 65 Battery voltage sensor 66 Brake switch 67 Torque sensor 68 Ignition switch 69 Vehicle speed sensor 70 Advanced driving support system 71 Display device 72 Buzzer 100 Power supply system

Claims (10)

A power supply system mounted on a vehicle having a normal driving mode by a driver and an automatic driving mode,
a first load circuit operated by power from the main battery and connected to a first load necessary for continuing the normal operation mode;
a second load circuit operated by power from the main battery or the additional battery and connected to a second load necessary for continuing the automatic operation mode;
a first relay provided on a power supply line that electrically connects the first load and the second load, the first relay conducting or interrupting between the first load circuit and the second load circuit;
a second relay that conducts or disconnects between the additional battery and the second load;
a controller that determines a driving mode of the vehicle;
The controller is
switching the second relay from on to off when the circuit voltage of the second load circuit is out of a predetermined voltage range when the operation mode is determined to be the normal operation mode;
A power supply system that maintains the ON state of the second relay regardless of the circuit voltage of the second load circuit when the operation mode is determined to be the automatic operation mode. 2. The power supply system according to claim 1, wherein the controller outputs a first command to maintain the ON state to the second relay when determining that the operation mode is the automatic operation mode. 3. The first command according to claim 2, wherein the first command is a command to maintain the ON state of the second relay regardless of the circuit voltage of the second load circuit and switching of the first relay from ON to OFF. power system. 4. The power supply system according to claim 2, wherein the controller outputs a second command for canceling the first command to the second relay when determining that the operation mode is the normal operation mode. The controller is
obtaining information about the state of the first relay and the state of the second relay;
when the second relay is in an off state, not outputting a control signal to turn it off to the first relay;
5. The power supply system according to any one of claims 1 to 4, wherein when said first relay is in an off state, it does not output a control signal to turn it off to said second relay. The controller is
determining whether the vehicle is in a parked state;
The power supply system according to any one of claims 1 to 5, wherein the second relay is turned off when it is determined that the vehicle is parked. The power supply according to any one of claims 1 to 6, wherein, when the second relay is in the off state, the controller switches the second relay from off to on at the timing when the vehicle speed of the vehicle equal to or higher than a predetermined speed is detected. system. The controller is
When the operation mode is determined to be the automatic operation mode, when the circuit voltage of the second load circuit is outside the predetermined voltage range, switching the first relay from on to off,
Any one of claims 1 to 7, wherein the second relay is turned off when the remaining battery level of the additional battery becomes equal to or less than a predetermined value after the operation mode is shifted from the automatic operation mode to the normal operation mode. Power system as described. The first relay is a normally open type relay,
The power supply system according to any one of claims 1 to 8, wherein the second relay is a normally closed type relay. A control method of a power supply system mounted on a vehicle having a normal driving mode by a driver and an automatic driving mode, which is executed by a controller,
The power system is
a first load circuit operated by power from the main battery and connected to a first load necessary for continuing the normal operation mode;
a second load circuit operated by power from the main battery or the additional battery and connected to a second load necessary for continuing the automatic operation mode;
a first relay provided on a power supply line that electrically connects the first load and the second load, the first relay conducting or interrupting between the first load circuit and the second load circuit;
a second relay that conducts or disconnects between the additional battery and the second load;
a controller that determines a driving mode of the vehicle;
The controller is
switching the second relay from on to off when the circuit voltage of the second load circuit is out of a predetermined voltage range when the operation mode is determined to be the normal operation mode;
A method of controlling a power supply system for maintaining the ON state of the second relay regardless of the circuit voltage of the second load circuit when the operation mode is determined to be the automatic operation mode.

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