Vehicle Power System

Abstract

To suppress a decrease of use opportunities of a functioning portion due to power supply, in a vehicle mounted with the functioning portion functioning for ensuring the safety of traffic such as automatic operation.SOLUTION: A vehicle power supply system is mounted on a vehicle capable of at least partially performing autonomous operation, and is equipped with a main power supply system, a back-up power supply system, and a high-pressure power supply. A back-up power supply control device can execute estimation processing estimating supply possible power which can be supplied from a back-up low-pressure power supply. During a vehicle performing autonomous operation in an autonomous operation mode, the back-up power supply control device, if the supply possible power is less than a second threshold value, outputs a signal indicating that a vehicle is prohibited to perform autonomous operation in the autonomous operation mode, and if the supply possible power is a third threshold value or less, outputs a signal indicating that the vehicle continues the autonomous operation mode and it is permitted to charge the back-up low-pressure power supply by power generated by the high-pressure power supply.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In recent years, efforts to provide access to sustainable transportation systems that take into consideration vulnerable traffic participants have become more active. To achieve this, we are focusing on research and development to further improve traffic safety and convenience through research and development in preventive safety. We are also focusing on research and development in autonomous driving as one of the technologies that contributes to preventive safety.

[0003] In vehicles equipped with functional units that function to ensure traffic safety, such as for autonomous driving, it is necessary to stabilize the power supply to these functional units. For example, Patent Document 1 discloses a system that can supply power to a load that functions for autonomous driving from a first power source and a third power source that are the vehicle's power sources, and can also supply power from a second power source that is capable of charging and discharging. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-142810 Summary of the Invention [Problem to be solved by the invention]

[0005] The system disclosed in Patent Document 1 makes it possible to reliably operate the load that functions to ensure safety by providing redundant power supply to the load. In such a system, if power supply from the second power source to the load cannot be provided, it is conceivable that the load will not operate in order to ensure high safety. This may result in fewer opportunities to use the functional unit for ensuring safety, which has been an issue. In order to solve the above problems, the present application aims to suppress the decrease in opportunities to use functional parts due to power supply in vehicles equipped with functional parts that function to ensure traffic safety, such as autonomous driving, and ultimately contribute to the development of sustainable transportation systems. [Means for solving the problem]

[0006] One aspect for achieving the above object is a vehicle power supply system that is mounted on a vehicle capable of at least partial autonomous driving in an autonomous driving mode that allows at least a driver to be exempt from steering operation, and that includes: 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 important emergency load and connected to the main power supply system; and a high-voltage power supply unit that is 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 the state of the backup low-voltage power supply and controls input and output of power from the backup low-voltage power supply, and the backup power supply control device is capable of executing an estimation process to estimate a suppliable power that indicates the amount of power or power that can be supplied from the backup low-voltage power supply to the important emergency load, and when the vehicle is not autonomously driving in the autonomous driving mode, the backup power supply control device executes the estimation process, and when the suppliable power estimated in the estimation process is equal to or greater than a first threshold value, and outputs a signal indicating that the vehicle is permitted to operate autonomously in the autonomous driving mode if the available power supply estimated by the estimation process is less than a second threshold, and when the vehicle is operating autonomously in the autonomous driving mode, the backup power supply control device executes the estimation process, and when the available power supply estimated by the estimation process is less than a third threshold, outputs a signal indicating that the vehicle is permitted to operate autonomously in the autonomous driving mode. and when the vehicle is operating autonomously in the autonomous driving mode, the backup power supply control device executes the estimation process, and when the available power supply estimated by the estimation process is less than a third threshold, outputs a signal indicating that the vehicle is permitted to continue operating in the autonomous driving mode and is permitted to charge the backup low-voltage power supply with power generated by the high-voltage power supply unit, and the first threshold is a threshold related to the amount of power or power that is determined based on the amount of power required to operate the emergency important load when the vehicle is operating autonomously in the autonomous driving mode. [Effects of the Invention]

[0007] According to the above configuration, a vehicle capable of at least partial autonomous driving can continue autonomous driving even when the available power supply from the backup low-voltage power supply decreases. This prevents a decrease in opportunities to use autonomous driving due to the power supply to loads related to autonomous driving. Therefore, the opportunities and time when the vehicle can perform autonomous driving increase, thereby improving marketability. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a vehicle power supply system according to an embodiment; [Figure 2] FIG. 10 is a diagram showing an example of the configuration of an important load in an emergency. [Figure 3] 3 is a flowchart showing the operation of the vehicle power supply system. [Figure 4] 3 is a flowchart showing the operation of the vehicle power supply system. [Figure 5] 3 is a timing chart showing the operation of the vehicle power supply system. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a vehicle power supply system according to the present invention will now be described with reference to the accompanying drawings.

[0010] [1. Vehicle power supply system configuration] [1-1. Overall configuration of vehicle power supply system] Fig. 1 is a schematic diagram of a vehicle power supply system 1. In Fig. 1, solid lines indicate power lines, and dashed lines indicate signal lines.

[0011] A vehicle power supply system 1 of a vehicle V in this 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 the step-down device 40. The step-down device 40 steps down the power flowing through the high-voltage power supply system 30 and outputs it 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.

[0012] In this embodiment, as an example, a case will be described in which the vehicle V is an electric vehicle equipped with a rotating electric machine MG as a power source for traveling. The rotating electric machine MG is, for example, a three-phase motor, and generates driving force using electric power supplied by an inverter unit (not shown), causing the vehicle V to travel. The vehicle V is equipped with a drive unit 321 equipped with the rotating electric machine MG, which will be described later. The vehicle V is equipped with a high-voltage power supply 31 that supplies driving electric power to the drive unit 321. The drive unit 321 is a load that receives a supply of high-voltage electric power output by the high-voltage power supply 31, and is included in a high-voltage load 32, which will be described later.

[0013] The vehicle V may be a vehicle equipped with an internal combustion engine. The internal combustion engine may 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 supply 31 (described later). In other words, the vehicle V may be an electric vehicle without an internal combustion engine, a hybrid vehicle equipped with an internal combustion engine and a rotating electric machine MG for driving the vehicle, or a vehicle driven by an internal combustion engine. The vehicle V is, for example, a vehicle capable of autonomous driving or automatic driving. When the vehicle V is equipped with an internal combustion engine, the high-voltage load 32 supplied with power from the high-voltage power supply 31 includes, for example, a starter motor.

[0014] [1-2. Main power system configuration] The main power supply system 10 includes a main low-voltage power supply 11 and a normal load 12 .

[0015] The main low-voltage power supply 11 is a power supply with a lower voltage than the high-voltage power supply 31. The main low-voltage 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, the main low-voltage power supply 11 may be a lead battery, a lithium-ion battery, a lithium polymer battery, a lithium iron phosphate battery, a metal hydride battery, or other batteries.

[0016] The main low-voltage power supply 11 is provided on the connection line L11. One end of the connection line L11 is connected to a contact C11 formed on the connection line L10, and the other end is connected to a ground line having a reference potential of the vehicle power supply system 1. The positive electrode side of the main low-voltage power supply 11 is connected to the contact C11 side of the connection line L11, and the negative electrode side is connected to the ground line side of the connection line L11.

[0017] A normal load 12 is connected to one end of the connection line L10. The normal load 12 (EL in the figure) is an electric power load mounted on the vehicle V. The normal load 12 may be a single device or may include multiple devices. In this embodiment, the normal load 12 is a functional unit that performs functions related to the running of the vehicle V. The normal load 12 includes, for example, a load that performs functions related to the running operation, stopping operation, or driving control of the vehicle V. The normal load 12 operates at a lower voltage than the high-voltage load 32, and therefore can be called a low-voltage load in comparison with the high-voltage load 32. Furthermore, the normal load 12 may include devices in the vehicle V that are known as auxiliary equipment.

[0018] Specifically, the normal load 12 includes an ECU 50 (Electronic Control Unit) capable of executing driving control of the vehicle V. The ECU 50 shown in FIG. 1 may be configured as a single ECU or may include multiple ECUs. For example, the normal load 12 may include some of the multiple ECUs provided in the vehicle V. Furthermore, the normal load 12 may include a control unit (not shown) that is mounted on the vehicle V and is different from the ECU 50.

[0019] Furthermore, the normal load 12 may include an auxiliary load used for braking the vehicle V, such as an automatic braking device. The normal load 12 may include an auxiliary load used for steering the vehicle V, such as an automatic steering device. The normal load 12 may include an auxiliary load used for acquiring external information about the vehicle V, such as LiDAR (Light Detection And Ranging). The normal load 12 may include instruments such as a wiper device, a power window device, and a meter panel.

[0020] [1-3. Configuration of backup power system] The backup power supply system 20 includes a backup power supply unit 21 and an important emergency load 22 .

[0021] The backup power supply unit 21 includes a backup low-voltage power supply 23 , a switching device 24 , and a backup power supply control device 25 that controls the switching device 24 .

[0022] The backup power supply unit 21 includes a first external connection terminal T211, a second external connection terminal T212, and a ground terminal T213. The other end of the connection line L10 is connected to the first external connection terminal T211. The ground terminal T213 is connected to a ground line.

[0023] The emergency important load 22 (EL in the figure) is an electric power load mounted on the vehicle V. The emergency important load 22 may be a single device or may include multiple devices. The emergency important load 22 operates at a lower voltage than the high-voltage load 32, and therefore can be called a low-voltage load in comparison with the high-voltage load 32.

[0024] The emergency important load 22 is connected to the second external connection terminal T212 of the backup power supply unit 21 by a connection line L21.

[0025] The switching device 24 has a first terminal T241, a second terminal T242, and a third terminal T243. The first terminal T241 is connected to a first external connection terminal T211 of the backup power supply unit 21 by a connection line L211. The second terminal T242 is connected to a second external connection terminal T212 of the backup power supply unit 21 by a connection line L212.

[0026] The switching device 24 includes a connection line L241 that connects the first terminal T241 and the second terminal T242. A first switch SW1 is provided on the connection line L241. In this embodiment, the first switch SW1 is a switch having a normally open (NO) contact. That is, when no operation signal is applied to the first switch SW1, the first switch SW1 is maintained in an OFF state, and is a contact that maintains the connection line L241 in an interrupted state. When an operation signal is applied to the first switch SW1, the first switch SW1 is switched to an ON state, and connects the first terminal T241 and the second terminal T242.

[0027] For example, if the first switch SW1 is configured as an electromagnetic switch that opens and closes using electromagnetic force, the first switch SW1 is maintained in an off state when no electromagnetic force is generated by the operating current, and maintains the connection line L241 in an interrupted state. The first switch SW1 may be an electromagnetic switch such as an electromagnetic contactor, an electromagnetic switch, or a relay, or may be a semiconductor switch element, or may be a circuit such as a DC / DC converter having a switching function.

[0028] The switching device 24 includes a connection line L242 that connects the connection line L241 and a third terminal T243. One end of the connection line L242 is connected to the connection line L241 at a contact C241 formed between the first switch SW1 of the connection line L241 and the second terminal T242, and the other end is connected to the third terminal T243.

[0029] A second switch SW2 is provided on the connection line L242. The second switch SW2 connects the connection line L242 in the on state, and disconnects the connection line L242 in the off state.

[0030] The second switch SW2 may be an electromagnetic switch such as an electromagnetic contactor, an electromagnetic switch, or a relay, or may be a semiconductor switch element, or may be a circuit such as a DC / DC converter having a switching function. In this embodiment, the second switch SW2 is a DC / DC converter. Therefore, as will be described later, when the second switch SW2 is in the on state, the second switch SW2 can increase or decrease the voltage output from the connection line L242 to the contact C241. In other words, the second switch SW2 in this embodiment has the function of connecting and disconnecting the connection line L242 and the function of converting the voltage output from the connection line L242 to the contact C241.

[0031] The switching device 24 includes a connection line L243 connected in parallel to the connection line L241. One end of the connection line L243 is connected to a contact C242 formed between a first terminal T241 of the connection line L241 and the first switch SW1. The other end of the connection line L243 is connected to a contact C243 formed between the contact C241 of the connection line L241 and the second terminal T242. A third switch SW3 is provided on the connection line L243.

[0032] In this embodiment, the third switch SW3 is a switch having a normally closed (NC) contact. That is, the third switch SW3 has a contact that is maintained in the ON state when no operation signal is applied to the third switch SW3. When an operation signal is applied to the third switch SW3, the third switch SW3 is switched to the OFF state, and the connection line L243 is brought into a connected state.

[0033] For example, if the third switch SW3 is configured as an electromagnetic switch that opens and closes using electromagnetic force, the third switch SW3 is maintained in an on state when no electromagnetic force is generated by the operating current, and maintains the connection line L243 in a connected state. The third switch SW3 may be an electromagnetic switch such as an electromagnetic contactor, an electromagnetic switch, or a relay, or may be a semiconductor switch element, or may be a circuit such as a DC / DC converter having a switching function.

[0034] In this embodiment, the first switch SW1 and the third switch SW3 are modularized as a switch module 241. The specific configuration of the switch module 241 is not limited, and for example, the switch module 241 may be a single semiconductor device or a circuit including multiple devices.

[0035] The switching device 24 includes a connection line L244 that connects the connection line L241 to the ground line. One end of the connection line L244 is connected to a contact C244 formed between the first switch SW1 of the connection line L241 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.

[0036] The backup low-voltage power supply 23 is a power supply with a lower voltage than the high-voltage power supply 31. The backup low-voltage power supply 23 outputs, for example, a direct current of 12 V. The backup low-voltage power supply 23 is, for example, a secondary battery that can be charged and discharged. Specifically, the backup low-voltage power supply 23 may be a lead battery, a lithium-ion battery, a lithium polymer battery, a lithium iron phosphate battery, a metal hydride battery, or other batteries.

[0037] The backup low-voltage power supply 23 is provided on the connection line L213. One end of the connection line L213 is connected to the third 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 on the connection line L213 so that the positive side is on the third terminal T243 side of the switching device 24 and the negative side is on the ground line side.

[0038] When the second switch SW2 is in the on state, the backup low-voltage power supply 23 supplies power to the backup power supply system 20 from the connection line L213 through the connection line L242 of the switching device 24. The power output from the backup low-voltage power supply 23 is stepped up or down to a desired voltage by the second switch SW2 and supplied to the backup power supply system 20. When the second switch SW2 is in the off state, the connection line L242 of the switching device 24 is cut off, so that no power is supplied from the backup low-voltage power supply 23 to the backup power supply system 20.

[0039] As described above, in the backup power supply system 20, a first switch SW1 having a normally open contact and a third switch SW3 having a normally closed contact are connected in parallel between the first terminal T241 and the second terminal T242.

[0040] When at least one of the first switch SW1 and the third switch SW3 is in the on state, the backup power supply system 20 is connected to the main power supply system 10. In this state, power can be supplied from the backup low-voltage power supply 23 to the main power supply system 10 through the first external connection terminal T211, and power can also be supplied from the main low-voltage power supply 11 to the emergency important load 22.

[0041] On the other hand, when both the first switch SW1 and the third switch SW3 are in the OFF state, the connection between the backup power supply system 20 and the main power supply system 10 is cut off.

[0042] The backup power supply control device 25 (BMS in the figure) is connected to a first switch SW1, a second switch SW2, and a third switch SW3 via signal lines. The backup power supply control device 25 controls the switching of the first switch SW1, the second switch SW2, and the third switch SW3 under the control of the ECU 50. The backup power supply control device 25 includes a processor such as a CPU (Central Processing Unit), and controls the backup power system 20 through cooperation between software and hardware by executing a program using the processor. In this case, the backup power supply control device 25 may include a storage unit that stores programs and data, and the storage unit is, for example, a ROM (Read Only Memory). The backup power supply control device 25 may also be configured with programmed hardware.

[0043] The backup power supply control device 25 outputs an operation signal to each of the first switch SW1, the second switch SW2, and the third switch SW3 via a signal line. The backup power supply control device 25 can switch each of the first switch SW1, the second switch SW2, and the third switch SW3 between a state in which an operation signal is output and a state in which an operation signal is not output.

[0044] The first switch SW1 is a normally open switch. The backup power supply control device 25 outputs an operation signal to the first switch SW1 to switch the first switch SW1 from an off state to an on state. The third switch SW3 is a normally closed switch. The backup power supply control device 25 outputs an operation signal to the third switch SW3 to switch the third switch SW3 from an on state to an off state.

[0045] The backup power supply control device 25 outputs an operation signal to the second switch SW2 to switch the second switch SW2 between an ON state and an OFF state. The backup power supply control device 25 also outputs an operation signal to the second switch SW2 to control the step-up or step-down of the second switch SW2. In other words, the backup power supply control device 25 controls the output voltage of the second switch SW2.

[0046] The backup power supply control device 25 operates by receiving power from, for example, the high-voltage power supply unit 36 ​​or the backup low-voltage power supply 23 .

[0047] The backup power supply control device 25 has a function of detecting the state of charge of the backup low-voltage power supply 23. The state of charge of the backup low-voltage power supply 23 is, for example, the SOC (State Of Charge). The backup power supply control device 25 detects the remaining battery capacity of the backup low-voltage power supply 23, for example, by detecting the voltage across the backup low-voltage power supply 23. The backup power supply control device 25 may also detect the remaining battery capacity 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, for example, based on the full charge capacity (FCC) of the backup low-voltage power supply 23 and the remaining capacity (RM) indicating the actual remaining capacity. Using these functions, the backup power supply control device 25 executes an estimation process to estimate the available power, which is the amount of power (for example, in watt-hours [Wh]) or power (for example, in watts [W]) that the backup low-voltage power supply 23 can output. The estimation process is a process of estimating the amount of power or available power that the backup low-voltage power supply 23 can supply to the important load 22 in an emergency, and can be rephrased as available power estimation process.

[0048] In this embodiment, the important emergency load 22 is a functional unit that performs functions related to the traveling of the vehicle V, and includes, for example, a load that performs functions related to the traveling operation, stopping operation, or driving control of the vehicle V. The important emergency load 22 includes a load that performs functions to respond to an emergency while the vehicle V is traveling. Specifically, the important emergency load 22 includes a load that performs functions related to the execution of a minimal risk maneuver (MRM) related to the traveling of the vehicle V. For example, the MRM includes an operation or control corresponding to at least one of the minimum traveling operation, stopping operation, and driving control required to safely move the vehicle V to the shoulder of the road and stop it even if the driving force of the driving source is lost.

[0049] The emergency important load 22 may include a part or all of the above-mentioned ECU 50 that is capable of executing driving control of the vehicle V. The emergency important load 22 may be a control unit mounted on the vehicle V and may include a control unit (not shown) different from the ECU 50.

[0050] Some of the loads included in the emergency important loads 22 may overlap with the loads included in the normal loads 12 of the main power supply system 10. In other words, some of the normal loads 12 may also be emergency important loads 22, and these loads belong to both the main power supply system 10 and the backup power supply system 20. This configuration makes it possible to make the emergency important loads 22 redundant. In other words, the emergency important loads 22 that overlap with the normal loads 12 of the main power supply system 10 can operate using power supplied to the main power supply system 10 and can also operate using power supplied to the backup power supply system 20. Therefore, the emergency important loads 22 that overlap with the normal loads 12 of the main power supply system 10 can operate even if an abnormality occurs in the main power supply system 10, and can also operate even if an abnormality occurs in the backup power supply system 20.

[0051] [1-4. High-voltage power supply system configuration] The high-voltage power supply system 30 includes a high-voltage power supply 31 and a high-voltage load 32 .

[0052] The high-voltage power supply 31 is a power supply that supplies power at 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 a connection line L31. One end of the connection line L31 is connected to a ground line, and the negative electrode of the high-voltage power supply 31 is connected to the ground line side of the connection line L31.

[0053] The high-voltage load 32 is an electric power load that operates at a higher voltage than the normal load 12 and the emergency important load 22, and operates using electric power supplied from the high-voltage power supply 31. In this embodiment, the high-voltage load 32 includes a drive unit 321 that drives the vehicle V, and an air conditioner 322 (A / C in the figure) that conditions the air inside the passenger compartment of the vehicle V.

[0054] The drive unit 321 includes a rotating electric machine MG and a power control unit PCU that controls the rotating electric machine MG. The power control unit PCU includes a DC / DC converter (not shown), an inverter (not shown), and the like.

[0055] The drive unit 321 is connected to the other end of the connection line L31. The drive unit 321 converts the DC power supplied from the high-voltage power supply 31 into three-phase AC power using the power control unit PCU and supplies the converted power to the rotating electric machine MG. As a result, the rotating electric machine MG generates power to drive the vehicle V using the power from the high-voltage power supply 31.

[0056] The air conditioner 322 is connected to a connection line L32 that connects to the connection line L31 at a contact C31 formed between the high-voltage power supply 31 of the connection line L31 and the drive unit 321. The air conditioner 322 operates using power from the high-voltage power supply 31.

[0057] The step-down device 40 is provided on the connection line L40. One end of the connection line L40 is connected to a contact C32, and the other end is connected to a 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 of the connection line L10. Here, the other end of the connection line L10 corresponds to the first external connection terminal T211 of the backup power supply system 20.

[0058] 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 .

[0059] The step-down device 40 reduces the voltage of the power flowing through the high-voltage power supply system 30. The step-down device 40 is, for example, a DC / DC converter. The step-down device 40 reduces the voltage output by 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.

[0060] The step-down device 40 can be switched between a connected state and a disconnected state. When the step-down device 40 is in a 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 step-down device 40 is in a disconnected state, the high-voltage power supply system 30 is disconnected from the main power supply system 10 and the backup power supply system 20.

[0061] 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. The battery may be, for example, 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 may be used as the high-voltage power supply 31. In this case, the high-voltage power supply 31 outputs a direct current of, for example, 200 V.

[0062] When the high-voltage power supply 31 includes a secondary battery, the high-voltage power supply 31 may include a power generation device that supplies power to the secondary battery. Alternatively, the high-voltage power supply 31 may be composed of only a power generation device. For example, a rotating electric machine MG may be used as the power generation device. For example, when braking the vehicle V, the rotating electric machine MG may be made to function as a regenerative brake, and the regenerative power generated by the rotating electric machine MG may be used as the high-voltage power supply 31. Also, when the vehicle V has an internal combustion engine, the vehicle V includes a generator driven by the power of the internal combustion engine. This generator may be used as the high-voltage power supply 31. The generator outputs the generated AC current via a boost circuit or a rectifier circuit (not shown). Alternatively, the AC current output by the generator may be supplied to the step-down device 40 directly or via a boost circuit or a rectifier circuit (not shown).

[0063] The high-voltage power supply 31 and the step-down device 40 constitute a high-voltage power supply unit 36. The high-voltage power supply unit 36 ​​is capable of outputting a voltage higher than the rated voltage of the backup power supply system 20. The high-voltage power supply unit 36 ​​may also be capable of outputting a voltage higher than the rated voltage of the main low-voltage power supply 11. The high-voltage power supply unit 36 ​​is composed of a high-voltage power supply 31 formed, for example, from a secondary battery, and a step-down device 40. When the high-voltage power supply 31 is formed from a generator driven by an internal combustion engine, a boost circuit or a rectifier circuit (not shown) connected to the generator may be used as a component replacing the step-down device 40. In other words, the high-voltage power supply unit 36 ​​may be composed of the generator and its peripheral circuits.

[0064] The high-voltage power supply unit 36 ​​is capable of operating in at least a normal operation mode and a high-voltage mode, and switches between the normal operation mode and the high-voltage mode under the control of, for example, the ECU 50. The normal operation mode is an operation mode intended to supply 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 voltage of the normal load 12 and the emergency important load 22. For example, in a vehicle V in which the rated output voltage of the main low-voltage power supply 11 and the backup low-voltage power supply 23 is 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.

[0065] The high-voltage mode is an operating mode intended to charge the backup low-voltage power supply 23 with power supplied by the high-voltage power supply unit 36. The output voltage of the high-voltage power supply unit 36 ​​in the high-voltage mode is a voltage that can charge the backup low-voltage power supply 23, and preferably a voltage that can charge the backup low-voltage power supply 23 to high voltage.

[0066] Even in the normal operation mode, if the output voltage of the high-voltage power supply unit 36 ​​is higher than the output voltage of the backup low-voltage power supply 23, the backup low-voltage power supply 23 is charged by the power of the high-voltage power supply unit 36. High-voltage charging refers to an operation that increases the charge state of the backup low-voltage power supply 23 in a shorter time than when the backup low-voltage power supply 23 is charged in the normal operation mode. In other words, high-voltage charging refers to an operation in which the high-voltage power supply unit 36 ​​operates in high-voltage mode to quickly charge the backup low-voltage power supply 23. In the high-voltage mode, the high-voltage power supply unit 36 ​​outputs a voltage that is, for example, two or three times or more than that in the normal operation mode. Furthermore, when the backup low-voltage power supply 23 is charged by the power output from the high-voltage power supply unit 36, the main low-voltage power supply 11 may be charged at the same time.

[0067] The vehicle power supply system 1 includes an ECU 50. As described above, the ECU 50 may include multiple ECUs, or may be a single device. The ECU 50 corresponds to an example of a vehicle control device.

[0068] 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 to which the ECU 50 is connected are not limited to those described above. The ECU 50 may be connected to devices mounted on the vehicle V that are not shown in FIG. 1.

[0069] The ECU 50 includes a processor such as a CPU, and controls each component of the vehicle power supply system 1 through cooperation between software and hardware by executing a program using the processor. In this case, the ECU 50 may include a storage unit, such as a ROM, that stores programs and data. Alternatively, the ECU 50 may be configured as programmed hardware.

[0070] An operation unit 55 is connected to the ECU 50. The operation unit 55 includes switches and the like operated by a user of the vehicle V. For example, the operation unit 55 includes an SSSW (Start Stop SWitch) 56 that the user operates to instruct the vehicle V to start and stop. The operation unit 55 also includes switches and the like that the user uses to instruct the vehicle V to perform autonomous driving. The operation unit 55 may be a wireless communication device that is wirelessly connected to a remote control device (not shown) and detects operations by the remote control device. Here, the user of the vehicle V is, for example, the driver of the vehicle V, but may also include a person other than the driver who uses the vehicle V.

[0071] When the vehicle V is stopped, the vehicle power supply system 1 is in an off state. In the off state of the vehicle power supply system 1, the ECU 50 maintains an operable state using power supplied from the high-voltage power supply 31. This state may be 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 power supply to some components of the ECU 50 is stopped, for example. Furthermore, in the sleep state or the low power consumption state, the operating clock number of the ECU 50 and the sampling frequency at which the ECU 50 detects the state of the operation unit 55 or the states of various sensors may be set to a longer cycle than when the vehicle V is operating.

[0072] When the vehicle power supply system 1 is in an off state, power is supplied to the normal load 12 and the emergency important load 22. This is to operate the emergency important load 22 and the normal load 12 while the vehicle power supply system 1 is in an off state. For example, the ECU 50 may monitor the detected value of a sensor included in the emergency important load 22 or a sensor connected to the emergency important load 22. Another example is a case where a camera included in the emergency important load 22 is used to monitor the surroundings of a parked vehicle V. In such a case, to operate the emergency important load 22, power is supplied from the high-voltage power supply unit 36 ​​to the emergency important load 22. Power is also supplied from the high-voltage power supply unit 36 ​​to the normal load 12. This power is called dark current. As described above, because the third switch SW3 is a normally closed type, power can be supplied from the main power supply system 10 to the emergency important load 22 via the third switch SW3 even when the backup power supply control device 25 is stopped.

[0073] In the vehicle power supply system 1, when the vehicle V is in a start-up state, power is supplied from the high-voltage power supply 31 to each component of the main power supply system 10. Furthermore, power is supplied from the high-voltage power supply unit 36 ​​to the main power supply system 10 and the emergency important load 22. When the vehicle V is in a stopped state, a dark current flows from the high-voltage power supply unit 36 ​​to the emergency important load 22 as described above.

[0074] Incidentally, if a short circuit or ground fault occurs in the main power supply system 10, the power supply from the high-voltage power supply unit 36 ​​to the emergency important load 22 may be stopped in order to protect the vehicle power supply system 1. For example, fuses (not shown) are provided at multiple locations in the circuits that make up the vehicle power supply system 1. If a ground fault or short circuit occurs, the fuses provided in the connection lines L31, L32, L40, etc. will blow, stopping the power supply from the high-voltage power supply unit 36 ​​to the emergency important load 22. In addition, the protection function may also shut off the output of the step-down device 40.

[0075] Even in such a case, the vehicle power supply system 1 can supply power from the backup low-voltage power supply 23 to the emergency important load 22 so that the power supply to the emergency important load 22 is not interrupted. This function realizes minimal-risk maneuvers while the vehicle V is autonomously driving. Specifically, by switching on the second switch SW2, 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 important load 22 is started. Alternatively, while the emergency important load 22 is operating during startup of the vehicle V, the backup power supply control device 25 may keep the second switch SW2 in the ON state to prepare for a situation in which the power supply from the step-down device 40 to the backup power supply system 20 is interrupted. In this case, it is sufficient that the output voltage of the second switch SW2 is adjusted in accordance with the output voltage of the step-down device 40 so that a current does not flow from the second switch SW2 toward the step-down device 40.

[0076] In order to achieve minimal-risk maneuvering, the ECU 50 sets the condition for the vehicle V to perform autonomous driving as being that the backup low-voltage power supply 23 is able to supply power to the important load 22 in an emergency.

[0077] The operating state in which the vehicle V is performing autonomous driving is called the autonomous driving mode. In the autonomous driving mode, the vehicle V drives without requiring at least steering operation by the driver. That is, in the autonomous driving mode, the autonomous driving control unit 220 drives the vehicle V without requiring steering by the user, using at least the lane keeping control unit 221 and the steering control unit 222. In the autonomous driving mode, the autonomous driving control unit 220 performs partial autonomous driving. Partial autonomous driving means executing some of the autonomous driving-related functions possessed by the autonomous driving control unit 220, and may or may not include, for example, steering by the lane keeping control unit 221 and the steering control unit 222, while executing autonomous driving functions by the brake control unit 223 and the driving control unit 224.

[0078] The ECU 50 executes autonomous driving of the vehicle V when triggered by operation of the operation unit 55 or a preset operating state of the vehicle V. That is, it starts the autonomous driving mode of the vehicle V. In this case, the ECU 50 controls the autonomous driving control unit 220 to start autonomous driving. Furthermore, while the vehicle V is performing autonomous driving, the ECU 50 stops the autonomous driving of the vehicle V when triggered by operation of the operation unit 55 or a preset operating state of the vehicle V. In this case, the ECU 50 controls the autonomous driving control unit 220 to end the autonomous driving mode, stop the autonomous driving, and transition to a normal driving mode. The normal driving mode is an operating mode that requires steering by the user to drive the vehicle V.

[0079] The ECU 50 causes the backup power supply control device 25 to estimate the available power supply of the backup low-voltage power supply 23. In this case, the backup power supply control device 25 estimates the available power supply and outputs the estimated value or outputs a signal based on the estimated value.

[0080] The backup power supply control device 25 outputs a signal means that the backup power supply control device 25 outputs a signal indicating that autonomous driving of the vehicle V is permitted, a signal indicating that continuation of autonomous driving of the vehicle V is permitted, 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 estimated values, but in this embodiment, an example will be described in which the backup power supply control device 25 performs the output.

[0081] When the ECU 50 starts autonomous driving of the vehicle V, the backup power supply control device 25 executes estimation processing to determine whether the power that can be supplied from the backup low-voltage power supply 23 is sufficient to realize a minimal-risk maneuver. In making this determination, the backup power supply control device 25 refers to various thresholds, which will be described later. These thresholds are held or stored in advance by the ECU 50 or the backup power supply control device 25.

[0082] When the backup power supply control device 25 determines that the available power supply of the backup low-voltage power supply 23 is insufficient, it outputs a signal indicating that autonomous driving of the vehicle V is prohibited. This signal can be called, for example, a prohibition signal. When the prohibition signal is input from the backup power supply control device 25, the ECU 50 does not start autonomous driving. Furthermore, when the prohibition signal is input from the backup power supply control device 25 while autonomous driving of the vehicle V is being performed, the ECU 50 ends the autonomous driving.

[0083] When it is determined that the backup low-voltage power supply 23 has sufficient power to supply, or when the power to supply is insufficient but can be restored by charging, 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 continuation of autonomous driving of the vehicle V is permitted. These signals can be called, for example, permission signals.

[0084] When starting autonomous driving of the vehicle V, the ECU 50 starts autonomous driving of the vehicle V on the condition that an enabling signal is input from the backup power supply control device 25. Furthermore, the ECU 50 continues autonomous driving if an enabling signal is input from the backup power supply control device 25 while autonomous driving of the vehicle V is being performed. The ECU 50 determines whether an enabling signal is input from the backup power supply control device 25 at predetermined time intervals while autonomous driving of the vehicle V is being performed, and ends autonomous driving if a state in which an enabling signal is not input continues for a predetermined time or longer.

[0085] [1-5. Configuration of important loads in emergencies] FIG. 2 is a block diagram showing an example of the configuration of the emergency important load 22. As shown in FIG. 2 illustrates an autonomous driving control unit 220 as an example of a functional unit included in the emergency important load 22. The autonomous driving control unit 220 includes, for example, a lane keeping control unit 221, a steering control unit 222, a brake control unit 223, and a driving control unit 224. Each functional unit constituting the autonomous driving control unit 220 may be configured with multiple ECUs, or the multiple functional units shown in FIG. 2 may be configured with a single ECU, and the autonomous driving control unit 220 may be a single ECU. Furthermore, the autonomous driving control unit 220 may be configured with a device having a control function different from an ECU, or may be realized by a computer executing software.

[0086] 2 shows a sensing unit 61, an electric steering unit 62, a brake drive device 63, and a throttle control device 64 as examples of functional units included in the emergency important load 22. Some or all of these may be included in the normal load 12. In addition, the emergency important load 22 may include functional units and drive units not shown in FIG. 2.

[0087] The sensing unit 61 includes one or more sensors that detect the situation outside the vehicle V and the driving state of the vehicle V. The sensing unit 61 is, for example, the above-mentioned LiDAR, a camera, a 4D sensor configured with radar and / or laser, an acceleration sensor, a gyro sensor, a geomagnetic sensor, a GNSS (Global Navigation Satellite System) unit, etc. The sensing unit 61 may be a unit that integrates multiple sensors, or the sensors included in the sensing unit 61 may be individually connected to the autonomous driving control unit 220.

[0088] While the vehicle V is performing autonomous driving, the sensing unit 61 outputs information necessary for performing autonomous driving of the vehicle V to the autonomous driving control unit 220 in accordance with the control of the autonomous driving control unit 220. When the vehicle V is not performing autonomous driving, the sensing unit 61 outputs information, such as information for the car navigation system of the vehicle V to display the position of the vehicle V, to the autonomous driving control unit 220 and the ECU 50.

[0089] The electric steering unit 62 controls the steering device of the vehicle V. For example, the electric steering unit 62 controls the steering of the vehicle V by operating a motor connected to a steering gear box (not shown).

[0090] The electric steering unit 62 drives the steering device of the vehicle V in accordance with the control of the autonomous driving control unit 220 while the vehicle V is performing autonomous driving. This allows the vehicle V to travel without the user performing steering operations. When the vehicle V is not performing autonomous driving, the electric steering unit 62 operates the steering device of the vehicle V in accordance with user operations via the operation unit 55 or a steering wheel (not shown).

[0091] The brake driving device 63 controls the braking device of the vehicle V. For example, the brake driving device 63 operates the brake system of the vehicle V using a motor or a hydraulic device to decelerate, stop, and maintain the stopped state of the vehicle V.

[0092] The brake drive device 63 controls the braking device in accordance with the control of the autonomous driving control unit 220 while the vehicle V is performing autonomous driving. This allows the vehicle V to perform autonomous driving, automatically slowing down and stopping the vehicle without the user operating the brakes. When the vehicle V is not performing autonomous driving, the brake drive device 63 operates the braking device of the vehicle V in response to user operation via the operation unit 55 or a brake pedal (not shown).

[0093] The throttle control device 64 controls the drive source that drives the vehicle V. In a vehicle V equipped with an internal combustion engine, the throttle control device 64 controls the supply of fuel to the internal combustion engine, and in a vehicle V equipped with a motor as a drive source, the throttle control device 64 controls the rotation of the motor.

[0094] The throttle control device 64 controls the drive source in accordance with the control of the autonomous driving control unit 220 while the vehicle V is performing autonomous driving. As a result, the vehicle V performs autonomous driving that automatically accelerates the vehicle V without the user performing any operation for acceleration, such as operating the throttle. When the vehicle V is not performing autonomous driving, the throttle control device 64 operates the drive source of the vehicle V in accordance with the user's operation via the operation unit 55 or an accelerator pedal (not shown).

[0095] The lane keeping control unit 221 and the steering control unit 222 realize a lane keeping function included in the autonomous driving function of the vehicle V. For example, the lane keeping control unit 221 calculates the steering amount and steering direction of the vehicle V based on information detected by the sensing unit 61 so that the vehicle V maintains a state in which it runs at an appropriate position relative to the lane. The steering control unit 222 controls the electric steering unit 62 based on the steering amount and steering direction calculated by the lane keeping control unit 221, and causes the vehicle V to steer so that the vehicle V maintains a state in which it runs at an appropriate position relative to the lane.

[0096] The brake control unit 223 controls the brake drive 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 causes the brake drive device 63 to maintain an appropriate driving speed of the vehicle V. Also, for example, the brake control unit 223 causes the brake drive device 63 to maintain an appropriate distance from other vehicles or obstacles located in the traveling direction of the vehicle V. Also, for example, the brake control unit 223 causes the brake drive device 63 to apply braking to avoid a collision with people or objects located in the traveling direction of the vehicle V or around the vehicle V. Also, for example, the brake control unit 223 causes the brake drive device 63 to maintain the stopped state of the vehicle V while the vehicle V is stopped.

[0097] The traveling 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 traveling control unit 224 causes the throttle control device 64 to maintain an appropriate traveling speed of the vehicle V.

[0098] In this way, the autonomous driving control unit 220 included in the emergency important load 22 controls the functional units of the vehicle V to perform autonomous driving of the vehicle V. The autonomous driving of the vehicle V includes at least the lane keeping function by the lane keeping control unit 221 and the steering control unit 222. Furthermore, the autonomous driving of the vehicle V may include control to stop the vehicle V at a safe position on the road in a so-called emergency.

[0099] [2. Vehicle power supply system operation] The operation of the vehicle power supply system 1 will now be described. 3 and 4 are flowcharts showing the operation of the vehicle power supply system 1. Fig. 3 shows the operation when the vehicle V starts autonomous driving, and Fig. 4 shows the operation while the vehicle V is performing autonomous driving. In this embodiment, an example will be described in which the backup power supply control device 25 performs the operations of Figs. 3 and 4 as described above, but there is no limitation to the ECU 50 or another control device performing these operations.

[0100] The backup power supply control device 25 detects a trigger for the ECU 50 to start autonomous driving (step S11). Step S11 is, for example, outputting a signal to the backup power supply control device 25 to notify that the ECU 50 will start autonomous driving.

[0101] The backup power supply control device 25 executes an estimation process to estimate the available power that the backup low-voltage power supply 23 can supply to the emergency important load 22 (step S12). The backup power supply control device 25 compares the estimated value obtained by the estimation process with a first threshold value and determines whether the estimated value is equal to or less than the first threshold value (step S13).

[0102] If it is determined that the estimated value is equal to or less than the first threshold value (step S13; YES), the backup power supply control device 25 outputs a signal indicating that autonomous driving is prohibited, i.e., a prohibition signal, to the ECU 50 (step S14), and ends this process. If it is determined that the estimated value is not equal to or less than the first threshold value (step S13; NO), the backup power supply control device 25 outputs a signal indicating that autonomous driving is permitted, i.e., a permission signal, to the ECU 50 (step S15), and ends this process.

[0103] 3, the ECU 50 can start autonomous driving of the vehicle V when the available power supply of the backup low-voltage power supply 23 is sufficient. In addition, the backup power supply control device 25 may perform the operation of Figure 3 at a preset period when the vehicle V is not executing the autonomous driving mode and no trigger for starting the autonomous driving mode has occurred.

[0104] 4, the backup power supply control device 25 determines whether the vehicle V is currently driving autonomously (step S21). If the vehicle V is not currently driving autonomously (step S21; NO), the backup power supply control device 25 waits.

[0105] If the vehicle V is performing autonomous driving (step S21; YES), the backup power supply control device 25 executes estimation processing (step S22). The backup power supply control device 25 compares the estimated value obtained by the estimation processing with a second threshold value and determines whether the estimated value is less than the second threshold value (step S23).

[0106] If it is determined that the estimated value is less than the second threshold value (step S23; YES), the backup power supply control device 25 outputs a signal indicating that autonomous driving is prohibited, i.e., a prohibition signal, to the ECU 50 (step S24), and ends this process. The prohibition signal output by the backup power supply control device 25 in step S24 is a signal indicating that continuation of autonomous driving is prohibited.

[0107] If it is determined that the estimated value is not less than the second threshold value (step S23; NO), the backup power supply control device 25 determines whether or not the estimated value is equal to or less than a third threshold value (step S25).

[0108] If it is determined that the estimated value is equal to or less than the third threshold value (step S23; YES), 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). As a result, the ECU 50 controls the high-voltage power supply 31 and / or the step-down device 40 to operate the high-voltage power supply unit 36 ​​in the high-voltage mode. In addition, the ECU 50 or the backup power supply control device 25 turns on the second switch SW2 to connect the high-voltage power supply unit 36 ​​to the backup low-voltage power supply 23. As a result, the backup low-voltage power supply 23 is charged with high voltage power output by the high-voltage power supply unit 36.

[0109] Thereafter, 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), and ends this process. The prohibition signal output by the backup power supply control device 25 in step S27 is a signal indicating that continuation of autonomous driving is permitted.

[0110] If it is determined that the estimated value is not equal to or less than the third threshold value (step S23; NO), the backup power supply control device 25 proceeds to step S27.

[0111] FIG. 5 is a timing chart showing the operation of vehicle power supply system 1. As shown in FIG. Fig. 5(a) shows the operating modes of vehicle V, Fig. 5(b) shows the operating modes of high-voltage power supply unit 36, and Fig. 5(c) shows the control of high-voltage power supply unit 36 ​​by ECU 50. Fig. 5(d) shows the state of backup power supply system 20. Fig. 5(e) is a graph showing the available power supply estimated by backup power supply control device 25, with the vertical axis representing the available power supply or amount of power and the horizontal axis representing time. Fig. 5(e) shows a first threshold value TH1, a second threshold value TH2, and a third threshold value TH3.

[0112] In this embodiment, the third threshold TH3 is the same as or lower than the first threshold TH1. The second threshold TH2 is lower than the third threshold TH3. The first threshold TH1 is a threshold related to the amount of power or electricity determined based on the amount of power required to operate the emergency important load 22 when the vehicle V is autonomously driving in the autonomous driving mode.

[0113] At time T1, the vehicle V is traveling in the normal traveling mode. At this time, the power that can be supplied by the backup low-voltage power supply 23 is lower than the first threshold value TH1. Therefore, the backup power supply control device 25 does not determine that backup power supply from the backup low-voltage power supply 23 is possible, and continues monitoring the status. The ECU 50 has instructed the high-voltage power supply unit 36 ​​to perform high-voltage charging, and the high-voltage power supply unit 36 ​​is supplying power in the high-voltage mode.

[0114] When high-voltage charging is performed, the power that can be supplied by the backup low-voltage power supply 23 is restored. In the example of FIG. 5, the power that can be supplied exceeds the first threshold value TH1 at time T2. In this case, the backup power supply control device 25 determines that backup power supply is possible at time T2. The ECU 50 instructs the high-voltage power supply unit 36 ​​to perform low-voltage charging. Low-voltage charging means charging the backup low-voltage power supply 23 with power that the high-voltage power supply unit 36 ​​outputs in the normal operation mode. In accordance with this instruction, the high-voltage power supply unit 36 ​​supplies power in the normal operation mode.

[0115] Assume that a trigger to start autonomous driving of vehicle V occurs at time T3. Here, the backup power supply control device 25 outputs a signal indicating that autonomous driving is permitted because the available power supply at time T3 is higher than the first threshold value TH1. ECU 50 starts the autonomous driving mode of vehicle V in accordance with the signal output by backup power supply control device 25.

[0116] In the example of FIG. 5, the available power supply of the backup low-voltage power supply 23 decreases after time T3 due to some factor. In this example, at time T4, the estimated value of the available power supply becomes lower than the third threshold value TH3 but higher than the second threshold value TH2. In this case, at time T4, the backup power supply control device 25 outputs a signal instructing charging in high-voltage mode through the operation of step S26. In response to this signal, the ECU 50 instructs the high-voltage power supply unit 36 ​​to perform high-voltage charging. This instruction is issued, for example, at time T5. In accordance with the instruction from the ECU 50, the high-voltage power supply unit 36 ​​executes high-voltage mode. This starts high-voltage charging of the backup low-voltage power supply 23, allowing the vehicle V to continue in the autonomous driving mode.

[0117] 3. Other Embodiments The above embodiment shows a specific example to which the present invention is applied, and does not limit the form to which the invention is applied.

[0118] For example, the method by which the backup power supply control device 25 estimates the suppliable power of the backup low-voltage power supply 23 is not limited to the above-mentioned method. For example, if the backup low-voltage power supply 23 is equipped with a power supply control device that manages and controls charging and discharging to the backup low-voltage power supply 23, the suppliable power may be estimated by the power supply control device continuously or at predetermined time intervals. In this case, the backup power supply control device 25 may obtain an estimated value of the suppliable power from the power supply control device of the backup low-voltage power supply 23.

[0119] 1 is one example, and for example, the step-down device 40 may be configured integrally with the high-voltage power supply 31, and the power boosted or increased in voltage by the step-down device 40 may be supplied to the high-voltage load 32. Also, the timing chart shown in FIG. 5 is merely one example of operation, and the operation of the vehicle power supply system 1 may be modified as appropriate.

[0120] 4. Configurations supported by the above embodiments The above embodiment supports the following configurations.

[0121] (Configuration 1) A vehicle power supply system mounted on a vehicle capable of at least partial autonomous driving in an autonomous driving mode that allows and executes at least an exemption from steering operation by the driver, 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 important emergency load and connected to the main power supply system; and a high-voltage power supply unit capable of outputting a voltage higher than the rated voltage of the backup power supply system, wherein the backup power supply system has a backup power supply control device that monitors the state of the backup low-voltage power supply and controls input and output of power from the backup low-voltage power supply, and the backup power supply control device is capable of executing an estimation process to estimate a suppliable power indicating the amount of power or power that can be supplied from the backup low-voltage power supply to the important emergency load, and when the vehicle is not autonomously driving in the autonomous driving mode, the backup power supply control device executes the estimation process, and if the suppliable power estimated by the estimation process is equal to or greater than a first threshold value, when the available power supply estimated by the estimation process is less than a third threshold, the backup power supply control device outputs a signal indicating that the vehicle is permitted to continue in the autonomous driving mode and that the backup low-voltage power supply is permitted to charge with power generated by the high-voltage power supply unit, and the first threshold is a threshold related to an amount of power or power determined based on an amount of power required to operate the emergency important load when the vehicle is autonomously driving in the autonomous driving mode. According to configuration 1, the autonomous driving mode is avoided when the backup low-voltage power supply's available power supply is low, and while the autonomous driving mode is being executed, the autonomous driving mode can be continued by charging even if the backup low-voltage power supply's available power supply decreases. This allows a vehicle that is at least partially capable of autonomous driving to continue autonomous driving even if the backup low-voltage power supply's available power supply decreases. Therefore, it is possible to prevent a decrease in opportunities to use autonomous driving due to the supply of power to loads related to autonomous driving. This increases the opportunities and time that the vehicle can execute autonomous driving, thereby improving marketability.

[0122] (Configuration 2) The vehicle power supply system according to configuration 1, wherein the third threshold is a value indicating an amount of electric power or power equal to or less than the first threshold and is a value indicating an amount of electric power or power greater than the second threshold. According to configuration 2, a minimum state is maintained in which power can be supplied from the backup low-voltage power supply to important loads in an emergency while the autonomous operation mode is being executed, and it is possible to prevent a decrease in opportunities to use autonomous operation due to the supply of power to loads related to autonomous operation.

[0123] (Configuration 3) The vehicle power supply system according to Configuration 1 or 2, wherein the high-voltage power supply unit is capable of operating in a high-voltage mode in which it outputs power at a voltage higher than a rated voltage of the backup power supply system, and a normal voltage mode in which it outputs power at a voltage lower than that in the high-voltage mode, and wherein the backup power supply control device outputs a signal indicating that it is permitted for the high-voltage power supply unit to charge the backup low-voltage power supply with power generated in the high-voltage mode when the available power supply estimated in the estimation process is equal to or less than a third threshold. According to the third aspect, when the available power supply of the backup low-voltage power supply drops while the autonomous operation mode is being executed, the available power supply can be restored in a shorter time. [Explanation of symbols]

[0124] 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 emergency load, 23...backup low-voltage power supply, 24...switching device, 25...backup power supply 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 section, 56...SSSW, 241...switch module, 321...drive unit, 322...air conditioning unit, CP...capacitor, MG...rotating electric machine, PCU...power control unit, SW1...first switch, SW2...second switch, SW3...third switch, V...vehicle.

Claims

1. A vehicle power supply system is mounted on a vehicle capable of at least partial autonomous driving in an autonomous driving mode that allows and executes the autonomous driving operation by at least a driver, and includes: 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 important emergency load and connected to the main power supply system; and a high-voltage power supply unit capable of outputting a voltage higher than the rated voltage of the backup power supply system, The backup power supply system includes: a backup power supply control device that monitors the state of the backup low-voltage power supply and controls input and output of power from the backup low-voltage power supply; the backup power supply control device is capable of executing an estimation process to estimate a supplyable power indicating an amount of power or power that can be supplied from the backup low-voltage power supply to the emergency important load, When the vehicle is not autonomously driving in the autonomous driving mode, the backup power supply control device Execute the estimation process, If the available power supply estimated in the estimation process is equal to or greater than a first threshold, outputting a signal indicating that the vehicle is permitted to autonomously drive in the autonomous driving mode; When the available power supply estimated in the estimation process is equal to or less than a third threshold, a signal indicating that the vehicle is permitted to autonomously drive in the autonomous driving mode is not output, When the vehicle is autonomously driving in the autonomous driving mode, the backup power supply control device Execute the estimation process, If the available power supply estimated in the estimation process is less than a second threshold, outputting a signal indicating that the vehicle is prohibited from autonomously driving in the autonomous driving mode; When the vehicle is autonomously driving in the autonomous driving mode, the backup power supply control device Execute the estimation process, when the suppliable power estimated in the estimation process is equal to or less than a third threshold, outputting a signal indicating that the vehicle is permitted to continue in 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 unit; the first threshold is a threshold related to an amount of power or power that is determined in advance based on an amount of power required to operate the emergency important load when the vehicle is autonomously driving in the autonomous driving mode, the second threshold is a predetermined value lower than the third threshold, The third threshold is a predetermined value indicating an amount of electric power or power equal to or less than the first threshold, and is a value indicating an amount of electric power or power greater than the second threshold.

2. the high-voltage power supply unit is capable of executing a high-voltage mode in which power is output at a voltage higher than a rated voltage of the backup power supply system, and a normal voltage mode in which power is output at a voltage lower than that of the high-voltage mode; 2. The vehicle power supply system according to claim 1, wherein, when the available power supply estimated in the estimation process is equal to or less than a third threshold, the backup power supply control device outputs a signal indicating that the high-voltage power supply unit is permitted to charge the backup low-voltage power supply with power generated in the high-voltage mode.

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