CN117734613A - Vehicle power supply system - Google Patents

Abstract

The invention provides a vehicle power supply system. In a vehicle equipped with a functional unit that functions to ensure traffic safety, such as automatic driving, a reduction in the utilization opportunity of the functional unit due to power supply is suppressed. The vehicle power supply system is mounted on a vehicle capable of autonomous driving at least in part, and includes a main power supply system, a backup power supply system, and a high-voltage power supply, and the backup power supply control device is capable of executing an estimation process for estimating a suppliable power that can be supplied from a backup low-voltage power supply, and when the vehicle is autonomous driving in an autonomous driving mode, outputs a signal indicating that autonomous driving of the vehicle in the autonomous driving mode is prohibited when the suppliable power is lower than a 2 nd threshold, and outputs a signal indicating that the vehicle is permitted to continue the autonomous driving mode and that the backup low-voltage power supply is charged with power generated by the high-voltage power supply when the suppliable power is lower than a 3 rd threshold.

Description

Vehicle power supply system

Technical Field

The present invention relates to a vehicle power supply system.

Background

In recent years, developments have become active to provide for the use of sustainable transportation systems that take care of people in a fragile standpoint among transportation participants. In order to achieve this object, research and development have been conducted to further improve traffic safety and convenience by research and development related to preventive safety. In addition, as one of technologies contributing to preventive safety, research and development related to automatic driving are being pursued.

In a vehicle equipped with a functional unit that functions to ensure traffic safety, such as automatic driving, it is required to stabilize the supply of power to such a functional unit. For example, patent document 1 discloses the following system: for a load that functions for automatic driving, electric power can be supplied from the 1 st power source and the 3 rd power source as vehicle power sources, and electric power can be supplied from the 2 nd power source that can be charged and discharged.

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2021-142810

Disclosure of Invention

Problems to be solved by the invention

In the system disclosed in patent document 1, by making the power supply to the load redundant, the load that functions to ensure safety can be reliably operated. In such a system, if the power supply from the 2 nd power source to the load is not possible, it is considered that the load is not operated in order to ensure high safety. Therefore, there are the following problems: the chance of utilizing the functional part for ensuring safety may be reduced.

The present application has been made to solve the above-described problems, and an object of the present application is to suppress a reduction in the utilization opportunity of a functional unit caused by power supply in a vehicle equipped with the functional unit functioning to ensure traffic safety, such as automatic driving. But also to facilitate the development of sustainable transportation systems.

Means for solving the problems

One aspect for achieving the above object is a vehicle power supply system mounted on a vehicle capable of being autonomously driven at least in part by an autonomous driving mode that allows at least steering operation by a driver to be avoided, the vehicle power supply system including: a main power supply system having a main low voltage power supply and a normal load; a backup power supply system having a backup low-voltage power supply and an emergency critical load, connected to the main power supply system; and a high-voltage power supply section capable of outputting a voltage higher than a rated voltage of the backup power supply system, wherein the backup power supply system has a backup power supply control device that monitors a state of the backup low-voltage power supply, controls input/output of electric power from the backup low-voltage power supply, is capable of performing estimation processing of estimating a suppliable electric power indicating an amount of electric power or electric power that can be supplied from the backup low-voltage power supply to the emergency critical load, performs the estimation processing when the vehicle is not autonomously driven in the autonomous driving mode, outputs a signal indicating that allows autonomous driving of the vehicle in the autonomous driving mode when the suppliable electric power estimated by the estimation processing is not less than a 1 st threshold, performs the estimation processing when the vehicle is being autonomously driven in the autonomous driving mode, performs the estimation processing when the suppliable electric power estimated by the estimation processing is less than a 2 nd threshold, performs prohibition of the output of electric power to the electric power supplied from the backup low-voltage power supply, performs the estimation processing when the vehicle is being autonomously driven in the autonomous driving mode when the autonomous driving is not estimated by the backup low-voltage power supply is not in the autonomous driving mode, allows the signal to be autonomously driven in the autonomous driving mode when the autonomous driving is allowed by the estimation processing is 3, the 1 st threshold is a threshold related to an amount of electricity or power that is determined based on an amount of electricity required to operate the emergency vital load when the vehicle is autonomously driven in the autonomous driving mode.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the above configuration, in the vehicle capable of at least partially autonomous driving, autonomous driving can be continued even when the available power of the backup low-voltage power source is reduced. This can suppress the following: the chance of being able to utilize autonomous driving is reduced due to the supply of electric power to the load related to autonomous driving. Therefore, the opportunity and time for the vehicle to perform autonomous driving increase, and thus the marketability can be improved.

Drawings

Fig. 1 is a schematic configuration diagram of a vehicle power supply system according to an embodiment.

Fig. 2 is a diagram showing a configuration example of an important load in an emergency.

Fig. 3 is a flowchart showing the operation of the vehicle power supply system.

Fig. 4 is a flowchart showing the operation of the vehicle power supply system.

Fig. 5 is a timing chart showing the operation of the vehicle power supply system.

Description of the reference numerals

1: vehicle power supply system, 10: power supply system, 11: main low voltage power supply, 12: normal load, 20: backup power supply system, 21: backup power supply unit, 22: critical load in emergency, 23: standby low voltage power, 24: switching device, 25: backup power control device, 30: high voltage power supply system, 31: high voltage power supply, 32: high voltage load, 36: high voltage power supply section, 40: step-down device, 50: ECU,55: operation unit, 56: SSSW,241: switch module, 321: drive unit, 322: air conditioner, CP: capacitor, MG: rotating electrical machine, PCU: power control unit, SW1: 1 st switch, SW2: 2 nd switch, SW3: 3 rd switch, V: a vehicle.

Detailed Description

An embodiment of a vehicle power supply system according to the present invention will be described below with reference to the drawings.

[1. Structure of vehicle Power supply System ]

[1-1. Overall structure of vehicle Power supply System ]

Fig. 1 is a schematic configuration diagram of a vehicle power supply system 1. In fig. 1, a solid line represents a power line, and a broken line represents a signal line.

The vehicle power supply system 1 of the vehicle V in the present embodiment includes a main power supply system 10, a backup power supply system 20 connected to the main power supply system 10, a high-voltage power supply system 30, and a step-down device 40. The high-voltage power supply system 30 is connected to the main power supply system 10 and the backup power supply system 20 via a step-down device 40. The step-down device 40 steps down the electric power flowing through the high-voltage power supply system 30, and outputs the electric power to the main power supply system 10 and/or the backup power supply system 20. The step-down device 40 is, for example, a DC/DC converter.

In the present embodiment, a description will be given of a case where the vehicle V is an electric vehicle provided with the rotating electrical machine MG as a power source for running, as an example. The rotating electrical machine MG is, for example, a 3-phase motor, and generates driving force by electric power supplied from an inverter unit, not shown, to run the vehicle V. The vehicle V includes a drive unit 321, and the drive unit 321 includes a rotating electrical machine MG described later. The vehicle V is mounted with a high-voltage power source 31 that supplies driving power to the driving unit 321. The driving unit 321 is a load that receives the supply of high-voltage power output from the high-voltage power supply 31, and is included in a high-voltage load 32 described later.

The vehicle V may be a vehicle on which an internal combustion engine is mounted. The internal combustion engine may also function as a power source for driving the vehicle V. Alternatively, the internal combustion engine may function as a power source for driving a generator, not shown, and charge a high-voltage power source 31, which will be described later. That is, the vehicle V may be an electric vehicle that does not include an internal combustion engine, a hybrid vehicle that includes an internal combustion engine and a rotating electrical machine MG for driving the vehicle, or a vehicle that is driven by the internal combustion engine. The vehicle V is, for example, a vehicle capable of autonomous driving or automatic driving. In the case where the vehicle V is equipped with an internal combustion engine, the high-voltage load 32 that receives supply of electric power from the high-voltage power source 31 includes, for example, a starter motor.

[1-2. Structure of Main Power System ]

The main power supply system 10 has a main low voltage power supply 11 and a normal load 12.

The main voltage source 11 is a power source having a voltage lower than that of the high voltage power source 31. The main power supply 11 outputs, for example, a direct current of 12 v. The main low-voltage power supply 11 is, for example, a secondary battery that can be charged and discharged. Specifically, as the main low-voltage power source 11, a lead battery, a lithium ion battery, a lithium polymer battery, a lithium iron phosphate battery, a metal hydride battery, or other batteries may be mentioned.

The main low-voltage power supply 11 is disposed on the connection line L11. One end of the connection line L11 is connected to the contact C11 formed on the connection line L10, and the other end is connected to the ground line having the reference potential of the vehicle power supply system 1. The positive side of the main low-voltage power supply 11 is connected to the contact C11 side of the connection line L11, and the negative side is connected to the ground side of the connection line L11.

The load 12 is typically connected to one end of the connection line L10. The normal load 12 (EL in the drawing) is an electric load mounted on the vehicle V. Typically, load 12 may be a single device or may comprise multiple devices. In the present embodiment, the normal load 12 is a functional unit that is responsible for a function related to the running of the vehicle V. The normal load 12 includes, for example, a load responsible for functions related to a running operation, a parking operation, or a driving control of the vehicle V. The load 12 generally operates at a lower voltage than the high voltage load 32, and therefore can be referred to as a low voltage load by comparison with the high voltage load 32. In addition, the normal load 12 may also include equipment called an auxiliary machine in the vehicle V.

Specifically, the normal load 12 includes an ECU 50 (Electronic Control Unit: electronic control unit) capable of executing driving control of the vehicle V. The ECU 50 shown in fig. 1 may be constituted by one ECU or may include a plurality of ECUs. For example, the normal load 12 may include a part of a plurality of ECUs provided in the vehicle V. The normal load 12 may include a control unit, not shown, mounted on the vehicle V, which is different from the ECU 50.

The normal load 12 may include an auxiliary load for braking the vehicle V, such as an automatic braking device. The normal load 12 may include an auxiliary load for steering the vehicle V, such as an automatic steering device. The normal load 12 may include an auxiliary load such as LiDAR (Light Detection And Ranging: light detection and ranging) for acquiring external information of the vehicle V. The load 12 may include a wiper device, a power window device, a dashboard, or the like.

1-3 Structure of Standby Power supply System

The backup power supply system 20 includes a backup power supply unit 21 and an emergency critical load 22.

The backup power supply unit 21 includes a backup power supply 23, a switching device 24, and a backup power supply control device 25 that controls the switching device 24.

The standby power supply unit 21 includes a 1 st external connection terminal T211, a 2 nd external connection terminal T212, and a ground terminal T213. The other end of the connection line L10 is connected to the 1 st external connection terminal T211. The ground terminal T213 is connected to ground.

The emergency important load 22 (EL in the figure) is an electric load mounted on the vehicle V. The emergency critical load 22 may be a single device or may include a plurality of devices. The critical load 22 operates at a lower voltage than the high-voltage load 32 in the emergency, and therefore can be referred to as a low-voltage load in comparison with the high-voltage load 32.

The emergency important load 22 is connected to the 2 nd external connection terminal T212 of the backup power supply unit 21 via the connection line L21.

The switching device 24 includes a 1 st terminal T241, a 2 nd terminal T242, and a 3 rd terminal T243. The 1 st terminal T241 is connected to the 1 st external connection terminal T211 of the backup power supply unit 21 through a connection line L211. The 2 nd terminal T242 is connected to the 2 nd external connection terminal T212 of the backup power supply unit 21 through the connection line L212.

The switching device 24 includes a connection line L241 connecting the 1 st terminal T241 and the 2 nd terminal T242. The 1 st switch SW1 is provided on the connection line L241. In the present embodiment, the 1 st switch SW1 is a switch having a contact of a normally open type (n.o. type). That is, the 1 st switch SW1 is the following contact: when the operation signal is not applied to the 1 st switch SW1, the disconnection state is maintained, and the connection line L241 is maintained in the disconnection state. The 1 st switch SW1 is switched to an on state by an operation signal applied thereto, and connects the 1 st terminal T241 and the 2 nd terminal T242.

For example, in the case where the 1 st switch SW1 is configured by an electromagnetic switch that is opened and closed by electromagnetic force, the 1 st switch SW1 maintains an off state when electromagnetic force based on operation current is not generated, and maintains the connection line L241 in a disconnected state.

The 1 st switch SW1 may be an electromagnetic switch such as an electromagnetic contactor, an electromagnetic switch, or a relay, or may be a semiconductor switching element, or may be a circuit such as a DC/DC converter having a switching function.

The switching device 24 includes a connection line L242 connecting the connection line L241 and the 3 rd terminal T243. One end of the connection line L242 is connected to the connection line L241 via a contact C241 formed between the 1 st switch SW1 and the 2 nd terminal T242 of the connection line L241, and the other end is connected to the 3 rd terminal T243.

The 2 nd switch SW2 is provided on the connection line L242. The 2 nd switch SW2 connects the connection line L242 in the on state and cuts off the connection line L242 in the off state.

The 2 nd switch SW2 may be an electromagnetic switch such as an electromagnetic contactor, an electromagnetic switch, or a relay, or may be a semiconductor switching element, or may be a circuit such as a DC/DC converter having a switching function. In the present embodiment, the 2 nd switch SW2 is a DC/DC converter. Therefore, as will be described later, the 2 nd switch SW2 can step up and down the voltage output from the connection line L242 to the contact C241 in the on state. That is, the 2 nd switch SW2 of the present embodiment has a function of connecting and disconnecting the connection line L242 and a function of converting the voltage output from the connection line L242 to the contact C241.

The switching device 24 includes a connection line L243 connected in parallel with the connection line L241. One end of the connection line L243 is connected to a contact C242 of the connection line L241 formed between the 1 st terminal T241 and the 1 st switch SW 1. The other end of the connection line L243 is connected to a contact C243 of the connection line L241 formed between the contact C241 and the 2 nd terminal T242. The 3 rd switch SW3 is provided on the connection line L243.

In the present embodiment, the 3 rd switch SW3 is a switch having a normally-off (n.c. type) contact. That is, the 3 rd switch SW3 is the following contact: in the case where the operation signal is not applied to the 3 rd switch SW3, the on state is maintained. The 3 rd switch SW3 is switched to the off state by the application of the operation signal, and the connection line L243 is switched to the off state.

For example, in the case where the 3 rd switch SW3 is constituted by an electromagnetic switch that is opened and closed by electromagnetic force, the 3 rd switch SW3 maintains an on state when electromagnetic force based on operation current is not generated, and the connection line L243 maintains a connected state.

The 3 rd switch SW3 may be an electromagnetic switch such as an electromagnetic contactor, an electromagnetic switch, or a relay, or may be a semiconductor switching element, or may be a circuit such as a DC/DC converter having a switching function.

In the present embodiment, the 1 st switch SW1 and the 3 rd switch SW3 are modularized into a switch module 241. The specific structure of the switching module 241 is not limited, and for example, the switching module 241 may be 1 semiconductor device or may be a circuit including a plurality of devices.

The switching device 24 includes a connection line L244 connecting the connection line L241 with the ground line. One end of the connection line L244 is connected to a contact C244 of the connection line L241 formed between the 1 st switch SW1 and the contact C241. The other end of the connection line L244 is connected to the ground line. A capacitor CP is provided on the connection line L244.

The standby power supply 23 is a power supply having a voltage lower than that of the high-voltage power supply 31. The backup low-voltage power supply 23 outputs a direct current of, for example, 12 v. The backup low-voltage power supply 23 is, for example, a secondary battery that can be charged and discharged. Specifically, as the backup low-voltage power supply 23, a lead battery, a lithium ion battery, a lithium polymer battery, a lithium iron phosphate battery, a metal hydride battery, or other batteries may be mentioned.

The standby low-voltage power supply 23 is provided to the connection line L213. One end of the connection line L213 is connected to the 3 rd terminal T243 of the switching device 24. The other end of the connection line L213 is connected to the ground line. The backup low-voltage power supply 23 is provided to the connection line L213 such that the positive electrode side is the 3 rd terminal T243 side of the switching device 24 and the negative electrode side is the ground line side.

When the 2 nd switch SW2 is in the on state, the backup low-voltage power supply 23 supplies electric power from the connection line L213 to the backup power supply system 20 through the connection line L242 of the switching device 24. The electric power output from the backup low-voltage power supply 23 is stepped up or down to a desired voltage by the 2 nd switch SW2, and is supplied to the backup power supply system 20. When the 2 nd switch SW2 is in the off state, the connection line L242 of the switching device 24 is in the off state, and therefore, no electric power is supplied from the backup low-voltage power supply 23 to the backup power supply system 20.

As described above, in the backup power supply system 20, the 1 st switch SW1 having a normally open contact and the 3 rd switch SW3 having a normally closed contact are connected in parallel between the 1 st terminal T241 and the 2 nd terminal T242.

When at least one of the 1 st switch SW1 and the 3 rd switch SW3 is in an on state, the backup power supply system 20 is connected to the main power supply system 10. In this state, the 1 st external connection terminal T211 can supply electric power from the backup low-voltage power supply 23 to the main power supply system 10, and can also supply electric power from the main low-voltage power supply 11 to the emergency critical load 22.

On the other hand, when both the 1 st switch SW1 and the 3 rd switch SW3 are in the off state, the connection between the backup power supply system 20 and the main power supply system 10 is disconnected.

The backup power supply control device 25 (BMS in the figure) is connected to the 1 st switch SW1, the 2 nd switch SW2 and the 3 rd switch SW3 via signal lines. The backup power supply control device 25 controls switching of the 1 st switch SW1, the 2 nd switch SW2 and the 3 rd switch SW3 in accordance with control of the ECU 50. The backup power supply control device 25 includes a processor such as a CPU (Central Processing Unit: central processing unit), and controls the backup power supply system 20 by cooperation of software and hardware by executing a program by the processor. In this case, the backup power supply control device 25 may include a storage unit for storing programs and data, and the storage unit may be, for example, a ROM (Read Only Memory). The backup power control 25 may also be comprised of programmed hardware.

The standby power control device 25 outputs operation signals to the 1 st switch SW1, the 2 nd switch SW2 and the 3 rd switch SW3 through signal lines, respectively. The standby power control device 25 can switch between a state in which the operation signal is output and a state in which the operation signal is not output with respect to the 1 st switch SW1, the 2 nd switch SW2, and the 3 rd switch SW3, respectively.

The 1 st switch SW1 is a normally open switch. The standby power control device 25 outputs an operation signal to the 1 st switch SW1 to switch the 1 st switch SW1 from the off state to the on state. The 3 rd switch SW3 is a normally-off switch. The backup power supply control device 25 outputs an operation signal to the 3 rd switch SW3 to switch the 3 rd switch SW3 from the on state to the off state.

The standby power control device 25 switches the 2 nd switch SW2 between the on state and the off state by outputting an operation signal to the 2 nd switch SW 2. Further, the standby power control device 25 controls the step-up or step-down in the 2 nd switch SW2 by outputting an operation signal to the 2 nd switch SW 2. That is, the standby power control device 25 controls the output voltage of the 2 nd switch SW 2.

The backup power supply control device 25 is operated by receiving power supply from the high-voltage power supply unit 36 or the backup low-voltage power supply 23, for example.

The backup power supply control device 25 has a function of detecting the state of charge of the backup power supply 23. The State Of Charge Of the backup low-voltage power supply 23 is, for example, SOC (State Of Charge). The backup power supply control device 25 detects the battery remaining amount of the backup low-voltage power supply 23 by detecting the voltage across the backup low-voltage power supply 23, for example. The backup power supply control device 25 may detect the remaining battery level of the backup low-voltage power supply 23 by counting the current input to and output from the backup low-voltage power supply 23. The backup power supply control device 25 may calculate the SOC based on, for example, the full charge capacity (FCC: full Charge Capacity) of the backup power supply 23 and RM (Remaining Capacity) indicating the actual remaining capacity. By these functions, the backup power supply control device 25 performs an estimation process of estimating the suppliable power, which is the amount of power (for example, in watt hours [ Wh ]) or power (for example, in watt [ W ]) that can be output by the backup power supply 23. The estimation process is a process of estimating the amount of power that can be supplied to the emergency critical load 22, which indicates the amount of power that can be supplied from the backup power source 23, and can be referred to as a power that can be supplied estimation process.

In the present embodiment, the emergency important load 22 is a functional unit that is responsible for a function related to the running of the vehicle V, and includes, for example, a load that is responsible for a function related to a running operation, a parking operation, or a driving control of the vehicle V. The emergency important load 22 includes a load responsible for a function for coping with an emergency while the vehicle V is traveling. Specifically, the emergency important load 22 includes a load responsible for the function related to the execution of the minimum risk policy (MRM: minimal Risk Maneuver) related to the running of the vehicle V. For example, the MRM includes an operation or control conforming to at least one of a minimum running operation, a parking operation, and a driving control required for safely moving the vehicle V to a shoulder of a road and parking the vehicle even if the driving force of the driving source is lost.

The emergency critical load 22 may include part or all of the aforementioned ECU 50 capable of executing driving control of the vehicle V. The emergency critical load 22 may include a control unit, not shown, mounted on the vehicle V, which is different from the ECU 50.

A part of the load included in the critical load 22 in the emergency may be repeated with the load included in the normal load 12 of the main power supply system 10. That is, a part of the normal load 12 may also become an emergency important load 22 belonging to both the main power supply system 10 and the backup power supply system 20. According to this structure, the emergency critical load 22 can be made redundant. In other words, the emergency critical load 22, which is overlapped with the normal load 12 of the main power supply system 10, can be operated by the electric power supplied to the main power supply system 10, or can be operated by the electric power supplied to the backup power supply system 20. Therefore, the emergency critical load 22, which is overlapped with the normal load 12 of the main power supply system 10, can operate even when an abnormality occurs in the main power supply system 10, and can operate even when an abnormality occurs in the backup power supply system 20.

1-4 Structure of high-voltage Power supply System

The high voltage power supply system 30 has a high voltage power supply 31 and a high voltage load 32.

The high-voltage power supply 31 is a power supply that supplies power of a higher voltage than the main low-voltage power supply 11 and the backup low-voltage power supply 23. The high-voltage power supply 31 is connected to the connection line L31. One end of the connection line L31 is connected to the ground, and the negative electrode side of the high-voltage power supply 31 is connected to the ground side of the connection line L31.

The high-voltage load 32 is an electric load that operates with a voltage higher than that of the normal load 12 and the emergency critical load 22, and operates with electric power supplied from the high-voltage power supply 31. In the present embodiment, the high-voltage load 32 includes a driving unit 321 that drives the vehicle V, and an air conditioning device 322 (a/C in the drawing) that performs air conditioning in the vehicle interior of the vehicle V.

The driving unit 321 includes a rotating electrical machine MG and a power control unit PCU that controls the rotating electrical machine MG. The power control unit PCU includes a DC/DC converter not shown, an inverter not shown, and the like.

The driving unit 321 is connected to the other end of the connection line L31. The drive unit 321 converts the direct-current power supplied from the high-voltage power source 31 into three-phase alternating-current power by the power control unit PCU, and supplies the three-phase alternating-current power to the rotating electrical machine MG. Thereby, the rotating electrical machine MG generates power for driving the vehicle V from the electric power of the high-voltage power source 31.

The air conditioner 322 is connected to the connection line L32, and the connection line L32 is connected to the connection line L31 through a contact C31 formed between the high-voltage power supply 31 of the connection line L31 and the driving unit 321. The air conditioner 322 operates by the electric power of the high-voltage power supply 31.

The voltage reducing device 40 is disposed on the connection line L40. One end of the connection line L40 is connected to the contact C32, and the other end is connected to the contact C12. The contact C32 is a contact formed between the high voltage power supply 31 and the contact C31 of the connection line L31. The contact C12 is a contact formed between the contact C11 of the connection line L10 and the other end portion of the connection line L10. Here, the other end portion of the connection line L10 corresponds to the 1 st external connection terminal T211 of the backup power supply system 20.

In this way, the high-voltage power supply system 30 is connected to the main power supply system 10 and the backup power supply system 20 via the step-down device 40.

The step-down device 40 steps down the electric power flowing in the high-voltage power supply system 30. The step-down device 40 is, for example, a DC/DC converter. The step-down device 40 steps down the voltage output from the high-voltage power supply system 30 and supplies the voltage to the main power supply system 10 and the backup power supply system 20.

The voltage reducing device 40 can switch between a connected state and a disconnected state. When the step-down device 40 is in the connected state, the high-voltage power supply system 30 is connected to the main power supply system 10 and the backup power supply system 20 via the connection line L40 and the step-down device 40. When the voltage reducing device 40 is in the off state, the high-voltage power supply system 30 is disconnected from the main power supply system 10 and the backup power supply system 20.

The high-voltage power supply 31 may be a power generation device mounted on the vehicle V or may be a battery mounted on the vehicle V. Examples of the battery include a secondary battery that can be charged and discharged. Specifically, a lithium ion battery, a lithium polymer battery, a lithium iron phosphate battery, a metal hydride battery, or other batteries can be used as the high-voltage power supply 31. In this case, the high-voltage power supply 31 outputs, for example, 200 v.

In the case where the high-voltage power source 31 includes a secondary battery, the high-voltage power source 31 may include a power generation device that supplies electric power to the secondary battery. The high-voltage power supply 31 may be constituted by only a power generation device. As the power generation device, for example, a rotating electrical machine MG may be used. For example, the rotating electrical machine MG is caused to function as regenerative braking at the time of braking the vehicle V, and regenerative power generated by the rotating electrical machine MG can be used as the high-voltage power source 31. In addition, when the vehicle V is a vehicle having an internal combustion engine, the vehicle V is provided with a generator driven by the power of the internal combustion engine. The generator may be used as a high voltage power supply 31. The generator outputs the generated ac current through a boost circuit and a rectifying circuit, not shown. The ac current output from the generator may be supplied to the step-down device 40 directly or via a step-up circuit or a rectifier circuit, not shown.

The high-voltage power supply 31 and the step-down device 40 constitute a high-voltage power supply section 36. The high-voltage power supply 36 can output a voltage higher than the rated voltage of the backup power supply system 20. The high-voltage power supply 36 may be configured to output a voltage higher than the rated voltage of the main low-voltage power supply 11.

The high-voltage power supply 36 is constituted by, for example, a high-voltage power supply 31 constituted by a secondary battery and a step-down device 40. In the case where the high-voltage power supply 31 is configured by a generator driven by an internal combustion engine, a boost circuit and a rectifier circuit, not shown, connected to the generator may be used as components of the step-down device 40. That is, the high-voltage power supply unit 36 may be constituted by a generator and peripheral circuits thereof.

The high-voltage power supply unit 36 is capable of executing at least a normal operation mode and a high-voltage mode, and is capable of switching between the normal operation mode and the high-voltage mode in accordance with control of the ECU 50, for example. The normal operation mode is an operation mode for the purpose of supplying electric power to the normal load 12 and the emergency important load 22. The output voltage of the high-voltage power supply unit 36 in the normal operation mode is a voltage included in the range of the rated input voltages of the normal load 12 and the emergency important load 22. For example, in the vehicle V in which the rated output voltages of the main low-voltage power supply 11 and the backup low-voltage power supply 23 are 12[ V ], the high-voltage power supply unit 36 outputs a voltage in the range of 12[ V ] to 15[ V ] in the normal operation mode.

The high-voltage mode is an operation mode for the purpose of charging the standby low-voltage power supply 23 with electric power supplied from the high-voltage power supply unit 36. The output voltage of the high-voltage power supply 36 in the high-voltage mode is a voltage capable of charging the backup low-voltage power supply 23, and preferably a voltage capable of high-voltage charging of the backup low-voltage power supply 23.

In the normal operation mode, when the output voltage of the high-voltage power supply 36 is higher than the output voltage of the backup low-voltage power supply 23, the backup low-voltage power supply 23 is charged with the electric power of the high-voltage power supply 36. The high-voltage charging means the following operations: the state of charge of the backup low-voltage power supply 23 is increased in a short time as compared with the case where the backup low-voltage power supply 23 is charged in the normal operation mode. That is, the high-voltage charging means the following operations: the high-voltage power supply unit 36 operates in the high-voltage mode, and thereby the backup low-voltage power supply 23 is charged promptly. In the high voltage mode, the high voltage power supply section 36 outputs, for example, a voltage 2 times, 3 times, or more the normal operation mode.

In addition, in the case where the backup low-voltage power supply 23 is charged with the electric power outputted from the high-voltage power supply unit 36, the main low-voltage power supply 11 may be charged at the same time.

The vehicle power supply system 1 includes an ECU 50. As described above, the ECU 50 may include a plurality of ECUs, or may be a single device. The ECU 50 corresponds to one example of a vehicle control device.

The ECU 50 is connected to the normal load 12, the emergency important load 22, the backup power supply control device 25, and the high-voltage load 32 via signal lines. The devices connected to the ECU 50 are not limited to the above-described portions. The ECU 50 may be connected to a device not shown in fig. 1 among the devices mounted on the vehicle V.

The ECU 50 includes, for example, a processor such as a CPU, and executes a program by the processor to control each part of the vehicle power supply system 1 by cooperation of software and hardware. In this case, the ECU 50 may include a memory unit for storing programs and data, and the memory unit may be, for example, a ROM. Furthermore, the ECU 50 may be constituted by programmed hardware.

The operation unit 55 is connected to the ECU 50. The operation unit 55 includes a switch or the like operated by a user of the vehicle V. For example, the operation portion 55 includes an SSSW (Start Stop SWitch: start-stop switch) 56 that is operated by a user to instruct the start and stop of the vehicle V. The operation unit 55 includes a switch or the like for a user to instruct the execution of autonomous driving of the vehicle V. The operation unit 55 may be a wireless communication device that is wirelessly connected to a remote control device, not shown, and detects an operation by the remote control device. Here, the user of the vehicle V is, for example, the driver of the vehicle V, but may include a person using the vehicle V other than the driver.

In the stopped state of the vehicle V, the vehicle power supply system 1 is turned off. In the off state of the vehicle power supply system 1, the ECU 50 is maintained in an operable state by the electric power supplied from the high-voltage power supply 31. The state may also be a state called a so-called sleep state or a low power consumption state. In the sleep state or the low power consumption state, the ECU 50 may be in a state in which, for example, the supply of electric power to some of the components of the ECU 50 is stopped. In the sleep state or the low power consumption state, the number of operation clocks of the ECU 50, the state of the ECU 50 detection operation unit 55, or the sampling frequency of the states of the various sensors may be set to a period longer than the period in which the vehicle V operates.

In the off state of the vehicle power supply system 1, electric power is supplied to the normal load 12 and the emergency critical load 22. This is to operate the emergency load 22 and the normal load 12 in the off state of the vehicle power supply system 1. For example, the ECU 50 monitors the detection value of a sensor included in the emergency load 22 or a sensor connected to the emergency load 22. For example, a function of monitoring the surroundings of the vehicle V in parking by a camera included in the emergency load 22 is performed. In such a case, the high-voltage power supply unit 36 supplies electric power to the emergency critical load 22 in order to operate the emergency critical load 22. The normal load 12 is similarly supplied with electric power from the high-voltage power supply 36. These powers are called so-called dark currents. Since the 3 rd switch SW3 is normally off as described above, even in a state where the backup power supply control device 25 is stopped, electric power can be supplied from the main power supply system 10 to the emergency critical load 22 via the 3 rd switch SW 3.

In the vehicle power supply system 1, electric power is supplied from the high-voltage power supply 31 to each part of the main power supply system 10 in a starting state of the vehicle V. Further, electric power is supplied from the high-voltage power supply unit 36 to the main power supply system 10 and the emergency critical load 22. In the stopped state of the vehicle V, as described above, the dark current flows from the high-voltage power supply portion 36 to the emergency critical load 22.

When a short circuit or a ground occurs in the main power supply system 10, the supply of electric power from the high-voltage power supply unit 36 to the emergency critical load 22 may be stopped in order to protect the vehicle power supply system 1. For example, fuses, not shown, are provided at a plurality of positions in a circuit constituting the vehicle power supply system 1. When the ground or short circuit occurs, fuses provided in the connection lines L31, L32, L40 and the like are cut, and the supply of electric power from the high-voltage power supply unit 36 to the emergency critical load 22 is stopped. Further, it is also possible to cause the voltage reducing device 40 to shut off the output by the protection function.

In this case, the vehicle power supply system 1 can also supply electric power from the backup low-voltage power supply 23 to the emergency critical load 22 so that the electric power supply to the emergency critical load 22 is not interrupted. This function implements a minimum risk strategy during autonomous driving of the vehicle V. Specifically, by switching the 2 nd switch SW2 on, the backup low-voltage power supply 23 is connected to the connection line L212, and power supply from the backup low-voltage power supply 23 to the emergency critical load 22 is started. Alternatively, the 2 nd switch SW2 may be turned on by the standby power control device 25 during the period in which the critical load 22 is operating in the emergency during the start of the vehicle V, and a power supply from the step-down device 40 to the standby power supply system 20 may be prepared. In this case, the output voltage of the 2 nd switch SW2 is adjusted in accordance with the output voltage of the step-down device 40 so that no current flows in the direction from the 2 nd switch SW2 toward the step-down device 40.

In order to implement the minimum risk strategy, the ECU 50 will be able to supply electric power to the emergency critical load 22 based on the backup low-voltage power source 23 as a condition for the vehicle V to perform autonomous driving.

The action state in which the vehicle V is performing autonomous driving is referred to as an autonomous driving mode. In the autonomous driving mode, the vehicle V travels in the autonomous driving mode at least without steering operation by the driver. That is, in the autonomous driving mode, the autonomous driving control unit 220 makes the vehicle V travel without requiring steering by the user by at least the lane keeping control unit 221 and the steering control unit 222. In the autonomous driving mode, the autonomous driving control portion 220 performs part of autonomous driving. The partial autonomous driving is to perform some of the functions related to autonomous driving, which the autonomous driving control unit 220 has, for example, steering by the lane keeping control unit 221 and the steering control unit 222, and may or may not include performing the autonomous driving functions by the brake control unit 223 and the travel control unit 224.

The ECU 50 executes autonomous driving of the vehicle V with an operation of the operation unit 55 or a preset operation state of the vehicle V as a trigger. That is, the autonomous driving mode of the vehicle V is started. In this case, the ECU 50 controls the autonomous driving control unit 220 to start autonomous driving. The ECU 50 also stops the autonomous driving of the vehicle V by triggering an operation of the operation unit 55 or a preset operation state of the vehicle V during the autonomous driving of the vehicle V. In this case, the ECU 50 controls the autonomous driving control unit 220 to end the autonomous driving mode and stop autonomous driving, and shifts to the normal running mode. The normal running mode is an operation mode in which steering by the user is required for running of the vehicle V.

The ECU 50 estimates the available power of the backup power source 23 through the backup power source control device 25. In this case, the backup power supply control device 25 estimates the available power and outputs an estimated value or an estimated value-based signal.

The standby power control device 25 performs signal output means: the backup power supply control device 25 outputs a signal indicating that autonomous driving of the vehicle V is permitted, a signal indicating that autonomous driving of the vehicle V is permitted to continue, and a signal indicating that autonomous driving of the vehicle V is prohibited. The output of these signals may be performed by the ECU 50 or another control device based on the estimated values, but in the present embodiment, an example of the execution by the backup power supply control device 25 is described.

When the ECU 50 starts autonomous driving of the vehicle V, the backup power supply control device 25 executes an estimation process to determine whether the suppliable power of the backup power supply 23 is sufficient for implementing the minimum risk policy. In this determination, the backup power supply control device 25 refers to various thresholds described later. These thresholds are held or stored in advance by the ECU 50 or the backup power supply control device 25.

When it is determined that the available power of the backup low-voltage power supply 23 is insufficient, the backup power supply control device 25 outputs a signal indicating prohibition of autonomous driving of the vehicle V. This signal can be referred to as a disable signal, for example. The ECU 50 does not start autonomous driving when a prohibition signal is input from the backup power supply control device 25. Further, the ECU 50 ends the autonomous driving when a prohibition signal is input from the backup power supply control device 25 in the course of executing the autonomous driving of the vehicle V.

The backup power supply control device 25 outputs a signal indicating that autonomous driving of the vehicle V is permitted or a signal indicating that autonomous driving of the vehicle V is permitted to continue, in a case where it is determined that the available power of the backup power supply 23 is sufficient or in a case where the available power is not sufficient but can be recovered by charging. These signals can be referred to as enable signals, for example.

When the autonomous driving of the vehicle V is started, the ECU 50 starts the autonomous driving of the vehicle V on the condition that an permission signal is input from the backup power supply control device 25. Further, the ECU 50 continues the autonomous driving when an permission signal is input from the backup power supply control device 25 in the course of executing the autonomous driving of the vehicle V. The ECU 50 determines whether or not an permission signal is input from the backup power supply control device 25 every predetermined time while the autonomous driving of the vehicle V is being performed, and ends the autonomous driving when the state in which the permission signal is not input continues for a predetermined time or longer.

[1-5 Structure of important load in case of Emergency ]

Fig. 2 is a block diagram showing a configuration example of the emergency important load 22.

In fig. 2, the autonomous driving control unit 220 is illustrated as a functional unit included in the emergency load 22. The autonomous driving control unit 220 includes, for example, a lane keeping control unit 221, a steering control unit 222, a braking control unit 223, and a travel control unit 224. Each of the functional units constituting the autonomous driving control unit 220 may be constituted by a plurality of ECUs, the plurality of functional units shown in fig. 2 may be constituted by 1 ECU, and the autonomous driving control unit 220 may be 1 ECU. The autonomous driving control unit 220 may be configured by a device having a control function different from the ECU, or may be realized by executing software by a computer.

Fig. 2 shows, as examples of functional units included in the emergency load 22, a sensing unit 61, an electric power steering unit 62, a brake driving device 63, and a throttle control device 64. Typically, some or all of these units may be included in load 12. The emergency load 22 may include a function unit or a drive unit not shown in fig. 2.

The sensing unit 61 includes 1 or more sensors that detect a condition outside the vehicle V, and a running state of the vehicle V. The sensing unit 61 is, for example, a 4D sensor, an acceleration sensor, a gyro sensor, a geomagnetic sensor, a GNSS (Global Navigation Satellite System: global positioning satellite system) unit, or the like, which is composed of the above-described LiDAR, camera, radar, and/or laser. The sensing unit 61 may be a unit in which a plurality of sensors are integrated, and the sensors included in the sensing unit 61 may be individually connected to the autonomous driving control portion 220.

The sensing unit 61 outputs information necessary for performing autonomous driving of the vehicle V to the autonomous driving control portion 220 in accordance with control of the autonomous driving control portion 220 during execution of autonomous driving of the vehicle V. When the vehicle V is not performing autonomous driving, the sensor unit 61 outputs information for displaying the position of the vehicle V, etc. to the autonomous driving control unit 220 and the ECU 50.

The electric power steering unit 62 controls the steering device of the vehicle V. For example, the electric power steering unit 62 controls the steering of the vehicle V by operating a motor coupled to a steering gear box, not shown.

The electric power steering unit 62 drives the steering device of the vehicle V under the control of the autonomous driving control unit 220 while the vehicle V is performing autonomous driving. This makes it possible to run the vehicle V without the user performing a steering operation. When the vehicle V is not autonomously driven, the electric power steering unit 62 operates a steering device of the vehicle V in response to a user's operation of the operation unit 55 and a steering wheel, not shown.

The brake driving device 63 controls the braking device of the vehicle V. For example, the brake driving device 63 operates a brake system of the vehicle V by a motor or a hydraulic device, and thereby, the vehicle V is decelerated, stopped, and the stopped state is maintained.

The brake driving device 63 controls the brake device in accordance with the control of the autonomous driving control unit 220 while the vehicle V is performing autonomous driving. Thereby, the vehicle V performs autonomous driving that automatically decelerates and stops even if the user does not perform a braking operation. The brake driving device 63 operates the brake device of the vehicle V in response to a user's operation of the operation unit 55 and a brake pedal, not shown, when the vehicle V is not autonomously driven.

The throttle control device 64 controls a drive source that runs the vehicle V. The throttle control device 64 controls the supply of fuel to the internal combustion engine in the vehicle V on which the internal combustion engine is mounted, and controls the rotation of the motor in the vehicle V on which the motor is mounted as a drive source.

The throttle control apparatus 64 controls the drive source in accordance with the control of the autonomous driving control portion 220 while the vehicle V is performing autonomous driving. Thus, the vehicle V performs autonomous driving in which the vehicle V is automatically accelerated even if the user does not perform an operation for acceleration such as a throttle operation. The throttle control device 64 operates a drive source of the vehicle V in response to a user's operation of the operation unit 55 and an accelerator pedal, not shown, when the vehicle V is not performing autonomous driving.

The lane keeping control section 221 and the steering control section 222 implement a lane keeping function included in the autonomous driving function of the vehicle V. For example, the lane keeping control section 221 calculates the steering amount and steering direction of the vehicle V based on the information detected by the sensing unit 61 so that the state in which the vehicle V travels in an appropriate position with respect to the lane is maintained. The steering control unit 222 controls the electric power steering unit 62 based on the steering amount and the steering direction calculated by the lane keeping control unit 221, and performs steering of the vehicle V so as to keep the vehicle V traveling in an appropriate position with respect to the lane.

The brake control unit 223 controls the brake driving device 63 to realize a brake control function included in the autonomous driving function of the vehicle V. For example, the brake control unit 223 maintains an appropriate running speed of the vehicle V by the brake driving device 63. Further, for example, the brake control section 223 maintains an appropriate distance with respect to other vehicles or obstacles located in the traveling direction of the vehicle V by the brake driving device 63. Further, for example, the brake control unit 223 performs braking for avoiding collision with a person or object existing in the traveling direction of the vehicle V or the surroundings of the vehicle V by the brake driving device 63. Further, for example, the brake control unit 223 maintains the stopped state of the vehicle V during the stop of the vehicle V by the brake driving device 63.

The travel control unit 224 controls the throttle control device 64 to realize an acceleration control function included in the autonomous driving function of the vehicle V. For example, the travel control unit 224 maintains an appropriate travel speed of the vehicle V by the throttle control device 64.

In this way, the autonomous driving control unit 220 included in the emergency critical load 22 controls the functional unit of the vehicle V to perform autonomous driving of the vehicle V. Autonomous driving of the vehicle V includes at least a function of lane maintenance by the lane maintenance control unit 221 and the steering control unit 222. Further, autonomous driving of the vehicle V may also include the following control: in a so-called emergency, the vehicle V is stopped on the road at a high-safety position.

[2 ] operation of vehicle Power supply System ]

The operation of the vehicle power supply system 1 will be described.

Fig. 3 and 4 are flowcharts showing the operation of the vehicle power supply system 1. Fig. 3 shows the actions when the vehicle V starts autonomous driving, and fig. 4 shows the actions during which the vehicle V performs autonomous driving. In the present embodiment, the example in which the backup power supply control device 25 performs the operations of fig. 3 and 4 is described as above, but the operations are not limited to be performed by the ECU 50 or other control devices.

The backup power supply control device 25 detects a trigger of the ECU 50 to start autonomous driving (step S11). Step S11 is, for example, the ECU 50 outputting a signal notifying the start of autonomous driving to the backup power supply control device 25.

The backup power supply control device 25 performs an estimation process of estimating the available power that the backup low-voltage power supply 23 can supply to the emergency critical load 22 (step S12). The backup power supply control device 25 compares the estimated value obtained by the estimation process with the 1 st threshold value, and determines whether or not the estimated value is equal to or smaller than the 1 st threshold value (step S13).

When it is determined that the estimated value is equal to or less than the 1 st threshold (step S13; yes), the backup power supply control device 25 outputs a prohibition signal indicating prohibition of autonomous driving to the ECU 50 (step S14), and ends the present process. When it is determined that the estimated value is not equal to or less than the 1 st threshold (step S13; no), the backup power supply control device 25 outputs a signal indicating that autonomous driving is permitted, that is, a permission signal, to the ECU 50 (step S15), and ends the present process.

By the operation of fig. 3, the ECU 50 can start autonomous driving of the vehicle V in the case where the available power of the backup power source 23 is sufficient.

In addition, regarding the operation of fig. 3, when the vehicle V does not execute the autonomous driving mode and when the trigger of the start of the autonomous driving mode does not occur, the backup power supply control device 25 may execute the operation of fig. 3 at a predetermined cycle.

In fig. 4, the backup power supply control device 25 determines whether the vehicle V is performing autonomous driving (step S21). In the case where the vehicle V is not performing autonomous driving (step S21; no), the backup power supply control device 25 stands by.

In the case where the vehicle V is performing autonomous driving (step S21; yes), the backup power supply control device 25 performs estimation processing (step S22). The backup power supply control device 25 compares the estimated value obtained by the estimation process with the 2 nd threshold value, and determines whether the estimated value is smaller than the 2 nd threshold value (step S23).

When it is determined that the estimated value is smaller than the 2 nd threshold (yes in step S23), the backup power supply control device 25 outputs a prohibition signal indicating prohibition of autonomous driving to the ECU 50 (step S24), and ends the present process. The prohibition signal output by the backup power supply control device 25 in step S24 is a signal indicating prohibition of continuation of autonomous driving.

When it is determined that the estimated value is not less than the 2 nd threshold (step S23; no), the backup power control device 25 determines whether or not the estimated value is not more than the 3 rd threshold (step S25).

When it is determined that the estimated value is equal to or less than the 3 rd threshold value (yes in step S23), the backup power supply control device 25 outputs a signal instructing the high-voltage power supply unit 36 to operate in the high-voltage mode to charge the backup low-voltage power supply 23 (step S26). Thus, the ECU 50 controls the high-voltage power supply 31 and/or the voltage reducing device 40 to operate the high-voltage power supply 36 in the high-voltage mode. The ECU 50 or the backup power supply control device 25 connects the high-voltage power supply 36 to the backup power supply 23 by turning on the 2 nd switch SW 2. Thereby, the high-voltage power outputted from the high-voltage power supply unit 36 is used to charge the backup low-voltage power supply 23 with high voltage.

Then, the backup power supply control device 25 outputs a signal indicating that autonomous driving of the vehicle V is permitted to the ECU 50 (step S27), ending the present process. The prohibition signal output by the backup power supply control device 25 in step S27 is a signal indicating that autonomous driving is permitted to continue.

When it is determined that the estimated value is not equal to or less than the 3 rd threshold value (step S23; no), the backup power supply control device 25 proceeds to step S27.

Fig. 5 is a timing chart showing the operation of the vehicle power supply system 1.

Fig. 5 (a) shows an operation mode of the vehicle V, fig. 5 (b) shows an operation mode of the high-voltage power supply unit 36, and fig. 5 (c) shows control of the high-voltage power supply unit 36 by the ECU 50. Fig. 5 (d) shows the state of the backup power supply system 20. Fig. 5 (e) is a graph showing the power that can be supplied estimated by the backup power supply control device 25, and the vertical axis represents the power that can be supplied or the amount of electricity and the horizontal axis represents time. Fig. 5 (e) shows the 1 st threshold TH1, the 2 nd threshold TH2, and the 3 rd threshold TH3.

In the present embodiment, the 3 rd threshold TH3 is the same value as the 1 st threshold TH1 or a value lower than the 1 st threshold TH1. The 2 nd threshold TH2 is a value lower than the 3 rd threshold TH3. The 1 st threshold TH1 is a threshold relating to the amount of electricity or power determined based on the amount of electricity required to operate the emergency critical load 22 when the vehicle V is autonomously driven in the autonomous driving mode.

At time T1, vehicle V is traveling in the normal traveling mode. At this time, the available power of the backup power supply 23 is lower than the 1 st threshold TH1. Therefore, the backup power supply control device 25 does not determine that backup power supply is possible based on the backup low-voltage power supply 23, and performs state monitoring. The ECU 50 instructs the high-voltage power supply unit 36 to charge at high voltage, and the high-voltage power supply unit 36 is supplying electric power in a high-voltage mode.

When the high-voltage charging is performed, the available power of the backup low-voltage power supply 23 is restored. In the example of fig. 5, at time T2, the available power exceeds the 1 st threshold TH1. In this case, the backup power supply control device 25 determines that the backup power supply is possible at time T2. The ECU 50 instructs the high-voltage power supply portion 36 to charge at a low voltage. The low-voltage charging means that the backup low-voltage power supply 23 is charged with electric power output in the normal operation mode by the high-voltage power supply unit 36. The high-voltage power supply 36 supplies power in the normal operation mode in accordance with the instruction.

At time T3, it is assumed that a trigger to start autonomous driving of the vehicle V occurs. Here, the suppliable power at time T3 is higher than the 1 st threshold TH1, and therefore, the backup power supply control device 25 outputs a signal indicating that autonomous driving is permitted. The ECU 50 starts the autonomous driving mode of the vehicle V in accordance with the signal output from the backup power supply control device 25.

In the example of fig. 5, the available power of the backup power supply 23 decreases after time T3 due to certain factors. In this example, at time T4, the estimated value of the power that can be supplied is a value lower than the 3 rd threshold TH3 but higher than the 2 nd threshold TH 2. In this case, the standby power control device 25 outputs a signal instructing to charge in the high voltage mode by the operation of step S26 at time T4. The ECU 50 receives the signal and instructs the high-voltage power supply unit 36 to charge at high voltage. The timing of this instruction is, for example, time T5. The high-voltage power supply section 36 executes a high-voltage mode in accordance with an instruction of the ECU 50. Thereby, high-voltage charging of the backup low-voltage power supply 23 is started, and the vehicle V can continue the autonomous driving mode.

[3 ] other embodiments ]

The above embodiment shows a specific example of application of the present invention, and is not limited to the mode of application of the present invention.

For example, the method of estimating the available power of the backup low-voltage power supply 23 by the backup power supply control device 25 is not limited to the above-described method. For example, in the case where a power supply control device that manages and controls charging and discharging of the backup low-voltage power supply 23 is mounted to the backup low-voltage power supply 23, the power supply control device may estimate the available power at all times or at predetermined intervals. In this case, the backup power supply control device 25 may acquire an estimated value of the available power from the power supply control device of the backup power supply 23.

Fig. 1 shows an example, and for example, the step-down device 40 may be integrally formed with the high-voltage power supply 31, and the power that has been stepped up or stepped down by the step-down device 40 may be supplied to the high-voltage load 32. The timing chart shown in fig. 5 is merely an example of the operation, and the operation of the vehicle power supply system 1 can be appropriately changed.

[4 ] the Structure supported by the above embodiment ]

The above embodiment supports the following structure.

(structure 1) a vehicle power supply system mounted on a vehicle capable of autonomous driving at least partially by an autonomous driving mode that allows at least steering operation by a driver to be dispensed with, the vehicle power supply system comprising: a main power supply system having a main low voltage power supply and a normal load; a backup power supply system having a backup low-voltage power supply and an emergency critical load, connected to the main power supply system; and a high-voltage power supply section capable of outputting a voltage higher than a rated voltage of the backup power supply system, wherein the backup power supply system has a backup power supply control device that monitors a state of the backup low-voltage power supply, controls input/output of electric power from the backup low-voltage power supply, is capable of performing estimation processing of estimating a suppliable electric power indicating an amount of electric power or electric power that can be supplied from the backup low-voltage power supply to the emergency critical load, performs the estimation processing when the vehicle is not autonomously driven in the autonomous driving mode, outputs a signal indicating that allows autonomous driving of the vehicle in the autonomous driving mode when the suppliable electric power estimated by the estimation processing is not less than a 1 st threshold, performs the estimation processing when the vehicle is being autonomously driven in the autonomous driving mode, performs the estimation processing when the suppliable electric power estimated by the estimation processing is less than a 2 nd threshold, performs prohibition of the output of electric power to the electric power supplied from the backup low-voltage power supply, performs the estimation processing when the vehicle is being autonomously driven in the autonomous driving mode when the autonomous driving is not estimated by the backup low-voltage power supply is not in the autonomous driving mode, allows the signal to be autonomously driven in the autonomous driving mode when the autonomous driving is allowed by the estimation processing is 3, the 1 st threshold is a threshold related to an amount of electricity or power that is determined based on an amount of electricity required to operate the emergency vital load when the vehicle is autonomously driven in the autonomous driving mode.

According to the configuration 1, it is possible to avoid execution of the autonomous driving mode in the case where the suppliable power of the backup low-voltage power source is low, and to continue the autonomous driving mode by performing charging even in the case where the suppliable power of the backup low-voltage power source is reduced during execution of the autonomous driving mode. In this way, in a vehicle that is at least partially capable of autonomous driving, autonomous driving can be continued even when the available power of the backup low-voltage power source is reduced. Therefore, the following can be suppressed: the chance of being able to utilize autonomous driving is reduced due to the supply of electric power to the load related to autonomous driving. Therefore, the opportunity and time for the vehicle to perform autonomous driving increase, and thus the marketability can be improved.

(structure 2) the vehicle power supply system according to structure 1, wherein the 3 rd threshold value is a value representing an amount of electricity or power that is less than the 1 st threshold value, and is a value representing an amount of electricity or power that is greater than the 2 nd threshold value.

According to the configuration 2, it is possible to maintain a minimum state in which power can be supplied from the backup power source to the emergency important load during execution of the autonomous driving mode, and it is possible to suppress the following: the chance of being able to utilize autonomous driving is reduced due to the supply of electric power to the load related to autonomous driving.

(configuration 3) the vehicle power supply system according to configuration 1 or 2, wherein the high-voltage power supply unit is capable of executing a high-voltage mode in which electric power having a voltage higher than a rated voltage of the backup power supply system is output, and a normal voltage mode in which electric power having a low voltage is output compared to the high-voltage mode, and the backup power supply control device outputs a signal indicating that charging of the backup low-voltage power supply by electric power generated by the high-voltage power supply unit in the high-voltage mode is permitted, when the suppliable electric power estimated by the estimation process is not more than a 3 rd threshold value.

According to the configuration 3, in the case where the available power of the backup low-voltage power supply is reduced during execution of the autonomous driving mode, the available power can be restored by a shorter time.

Claims (3)

1. A vehicle power supply system mounted on a vehicle capable of autonomous driving at least in part by an autonomous driving mode that allows at least steering operation by a driver to be dispensed with, the vehicle power supply system comprising: a main power supply system having a main low voltage power supply and a normal load; a backup power supply system having a backup low-voltage power supply and an emergency critical load, connected to the main power supply system; and a high-voltage power supply unit that is capable of outputting a voltage higher than the rated voltage of the backup power supply system,

The backup power supply system has a backup power supply control device that monitors a state of the backup low-voltage power supply, controls input/output of electric power from the backup low-voltage power supply,

the backup power supply control apparatus is capable of performing an estimation process of estimating a suppliable power representing an amount of power or power that can be supplied from the backup low-voltage power supply to the emergency critical load,

the backup power supply control device executes the estimation process when the vehicle is not autonomously driven in the autonomous driving mode, outputs a signal indicating that autonomous driving of the vehicle in the autonomous driving mode is permitted when the suppliable power estimated by the estimation process is equal to or greater than a 1 st threshold,

the backup power supply control device performs the estimation process when the vehicle is being autonomously driven in the autonomous driving mode, outputs a signal indicating prohibition of autonomous driving of the vehicle in the autonomous driving mode in a case where the suppliable power estimated by the estimation process is smaller than a 2 nd threshold value,

the backup power supply control device performs the estimation process when the vehicle is being autonomously driven in the autonomous driving mode, and outputs a signal indicating that the vehicle is permitted to continue the autonomous driving mode and that the backup low-voltage power supply is permitted to be charged with the power generated by the high-voltage power supply portion in a case where the suppliable power estimated by the estimation process is equal to or less than a 3 rd threshold value,

The 1 st threshold is a threshold related to an amount of electricity or power that is determined based on an amount of electricity required to operate the emergency vital load when the vehicle is autonomously driven in the autonomous driving mode.

2. The vehicle power supply system according to claim 1, wherein,

the 3 rd threshold value is a value representing an amount of electricity or power less than the 1 st threshold value, and is a value representing an amount of electricity or power greater than the 2 nd threshold value.

3. The vehicle power supply system according to claim 1 or 2, wherein,

the high-voltage power supply unit is capable of executing a high-voltage mode in which power having a voltage higher than a rated voltage of the backup power supply system is output, and a normal voltage mode in which power having a low voltage is output compared to the high-voltage mode,

the backup power supply control device outputs a signal indicating that the backup low-voltage power supply is permitted to be charged with the power generated by the high-voltage power supply unit in the high-voltage mode when the suppliable power estimated by the estimation process is equal to or less than a 3 rd threshold value.