Vehicle power supply system

Abstract

To prolong a time during which power can be supplied from an autonomous driving backup power supply when the voltage of a main power supply drops.SOLUTION: A vehicle power supply system 100 includes: a main power supply 10 that supplies power to a main system 41 and a sub-system 42 of a steering device 40 including the main system 41 and the sub-system 42; a backup power supply 20 connected to the main system 41; an autonomous driving backup power supply 30 connected to the sub-system 42; and a controller 80 that adjusts power supply of the backup power supply 20 and the autonomous driving backup power supply 30. When voltage of the main power supply 10 drops below a predetermined threshold value, the controller 80 causes the backup power supply 20 to supply power to the main system 41 while causing the autonomous driving backup power supply 20 to stop supplying power to the sub-system 42.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a configuration of a vehicle power supply system for an electric vehicle equipped with an autonomous driving system. [Background technology]

[0002] Patent Document 1 discloses a steering system that includes a steering device with two control systems, a main system and a sub-system, a main power supply, and a backup power supply. In this steering system, during normal power supply, in which power is supplied from the main power supply to the main system and the sub-system, the sub-system is operated in coordination with the main system. On the other hand, in this steering system, when power cannot be supplied from the main power supply, the main system is not operated, but the sub-system is operated and power is supplied from the backup power supply to the sub-system. As a result, this steering system has the effect of continuing the power supply from the backup power supply for a relatively long period of time. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-7759 Summary of the Invention [Problem to be solved by the invention]

[0004] Recently, electric vehicles equipped with automatic driving systems have been used. Such electric vehicles are equipped with an automatic driving backup power supply that supplies power to the steering device and the brake device when power supply from the main power supply is unavailable. When power supply from the main power supply is unavailable, it is required to maintain power supply from the automatic driving backup power supply for as long as possible to ensure evacuation driving time.

[0005] Therefore, the present disclosure aims to extend the time during which power can be supplied from the automatic driving backup power supply when the voltage of the main power supply drops in a vehicle power supply system equipped with a main power supply and an automatic driving backup power supply. [Means for solving the problem]

[0006] The vehicle power supply system of the present disclosure is a vehicle power supply system including a main power supply that supplies power to a main system and a sub-system of a steer-by-wire steering device that has two steering control systems, a main system and a sub-system, a backup power supply connected to the main system, a backup power supply for automatic driving connected to the sub-system, and a control unit that adjusts the power supply of the backup power supply and the backup power supply for automatic driving, wherein when the voltage of the main power supply drops below a predetermined threshold, the control unit causes the backup power supply to supply power to the main system and stops the power supply from the backup power supply for automatic driving to the sub-system.

[0007] This allows the amount of power supplied from the automatic driving backup power supply to be reduced, so that when the voltage of the main power supply drops, the time during which power can be supplied from the automatic driving backup power supply can be extended compared to when power is supplied to a sub-system of the steering device.

[0008] In the vehicle power supply system of the present disclosure, the control unit may adjust the operation of the main system and the sub-system, and when the voltage of the main power supply drops below a predetermined threshold, operate the main system and stop the operation of the sub-system, supply power from the backup power supply to the main system, and stop the power supply from the automatic driving backup power supply to the sub-system.

[0009] This makes it possible to stop the power supply from the automatic operation backup power supply to the sub-system in a simple manner.

[0010] In the vehicle power supply system of the present disclosure, the backup power supply for autonomous driving may be connected to the sub-system and a brake device, and may supply power to the brake device when the voltage of the main power supply drops below a predetermined threshold.

[0011] As a result, when the voltage of the main power supply drops, the time during which power can be supplied from the automatic driving backup power supply to the brake device can be extended compared to when power is supplied to the steering device sub-system. [Effects of the Invention]

[0012] The present disclosure is capable of extending the time during which power can be supplied from the automatic driving backup power supply when the voltage of the main power supply drops in a vehicle power supply system equipped with a main power supply and an automatic driving backup power supply. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a system diagram showing a configuration of a vehicle power supply system according to an embodiment; [Figure 2] 2 is a flowchart showing the operation of the vehicle power supply system shown in FIG. [Figure 3] 2 is an explanatory diagram showing the state of power supply to the steering device and the brake device when the voltage of the main power supply drops in the vehicle power supply system shown in FIG. 1. FIG. [Figure 4] FIG. 1 is an explanatory diagram showing the power supply state to a steering device and a brake device when the voltage of a main power supply drops in a conventional vehicle power supply system. DETAILED DESCRIPTION OF THE INVENTION

[0014] A vehicle power supply system 100 according to an embodiment will now be described with reference to the drawings. As shown in Fig. 1, the vehicle power supply system 100 includes a main power supply 10, a backup power supply 20, an automatic driving backup power supply 30, and a control unit 80. In Figs. 1, 3, and 4, dashed lines indicate the flow of power, and dot-dash lines indicate the flow of signals.

[0015] The main power supply 10 includes a DC / DC converter 11 and an auxiliary battery 12. The DC / DC converter 11 steps down the voltage of a high-voltage drive power supply (not shown) mounted on the vehicle to charge the auxiliary battery 12. The auxiliary battery 12 supplies power to the steering device 40 and the braking device 70. Furthermore, when the voltage of the auxiliary battery 12 drops, the DC / DC converter 11 supplies power to the steering device 40 and the braking device 70.

[0016] The backup power supply 20 includes an internal capacitor 21. The backup power supply 20 is charged by the main power supply 10, and passes the power supplied by the main power supply 10 through to supply power to the main system 41 of the steering device 40.

[0017] The automatic driving backup power supply 30 includes an internal capacitor 31. The automatic driving backup power supply 30 is charged by the main power supply 10, and passes the power supplied by the main power supply 10 through the backup power supply 30 to supply power to the brake device 70 and the sub-system 42 of the steering device 40.

[0018] Steering device 40 is a steer-by-wire type steering device equipped with two steering control systems: a main system 41 and a sub-system 42. Main system 41 is equipped with a main reaction force motor 51, a main operation angle sensor 52, a main torque sensor 53, a main ECU 54, and a main steering motor 55.

[0019] Main reaction force motor 51 is a motor that applies a reaction force to a steering wheel (not shown) in response to a steering operation by the driver. Main operation angle sensor 52 detects the steering angle. Main torque sensor 53 detects the steering operation force by the driver. Main steering motor 55 turns the front wheels left and right. Main ECU 54 controls main reaction force motor 51 and main steering motor 55.

[0020] Similarly, the sub-system 42 includes a sub-reaction force motor 61 , a sub-operation angle sensor 62 , a sub-torque sensor 63 , a sub-ECU 64 , and a sub-steered motor 65 .

[0021] Main ECU 54 and sub-ECU 64 are computers equipped with a CPU, which is an internal processor for information processing, and memory for storing control programs and control data. Main ECU 54 and sub-ECU 64 operate in two control modes: an independent control mode and a cooperative control mode. In the independent control mode, main ECU 54 and sub-ECU 64 independently control main reaction force motor 51 and sub reaction force motor 61, and main steering motor 55 and sub steering motor 65. In the cooperative control mode, sub-ECU 64 controls sub reaction force motor 61 and sub steering motor 65 so as to follow the control of main reaction force motor 51 and main steering motor 55 by main ECU 54.

[0022] The control unit 80 adjusts the power supply between the backup power supply 20 and the automatic driving backup power supply 30. More specifically, the control unit 80 adjusts the operation of the main system 41 and the sub system 42 of the steering device 40 based on the voltage of the main power supply 10 detected by a voltage sensor 83, thereby adjusting the power supply between the backup power supply 20 and the automatic driving backup power supply 30. The control unit 80 is a computer that includes a CPU 81, which is a processor that performs information processing, and a memory 82 that stores control programs and control data. The operation of the control unit 80 is achieved when the PCU 81 executes the control program stored in the memory 82.

[0023] The automatic driving interface box 85 is an interface device that exchanges data between an automatic driving kit (not shown) and other devices mounted on the vehicle.

[0024] Next, the operation of the vehicle power supply system 100 according to the embodiment will be described with reference to FIGS.

[0025] As shown in step S101 of Fig. 2, the control unit 80 determines whether a signal is being input from the automatic driving interface box 85. If the determination in step S101 of Fig. 2 is YES, the control unit 80 determines in step S102 of Fig. 2 that the vehicle equipped with the vehicle power supply system 100 is an automatic driving vehicle. Then, the control unit 80 proceeds to step S103 of Fig. 2.

[0026] On the other hand, if the determination in step S101 of Fig. 2 is NO, the control unit 80 determines that the vehicle equipped with the vehicle power supply system 100 is not an autonomous vehicle, and is a vehicle to which the operation shown in Fig. 2 does not apply. Then, the control unit 80 skips steps S102 to S105 of Fig. 2 and ends the process.

[0027] In step S103 of Fig. 2, the control unit 80 determines whether the voltage of the main power supply 10 detected by the voltage sensor 83 has dropped below a predetermined threshold. A voltage drop may occur, for example, when the power consumption of the steering device 40 or the brake device 70 increases rapidly and the supply of power from the DC / DC converter 11 is delayed. Another possible voltage drop is when the auxiliary battery 12 is not sufficiently charged and power consumption increases rapidly, causing a voltage drop.

[0028] Here, the predetermined threshold is a voltage at which the steering device 40 and the brake device 70 can operate normally. For example, if the normal operating voltage is 12V, the predetermined threshold may be a voltage of about 10V or about 9V.

[0029] If the determination in step S103 of FIG. 2 is NO, the control unit 80 returns to step S103 of FIG. 2 and continues monitoring the voltage of the main power supply 10.

[0030] If the control unit 80 determines YES in step S103 of Fig. 2, the control unit 80 proceeds to step S104 of Fig. 2. Then, in step S104 of Fig. 2, the control unit 80 determines whether the sub-system 42 is connected to the capacitor 31 of the automatic operation backup power supply 30. This determination may be made, for example, based on whether the power supply voltage input to the sub-system 42 exceeds a predetermined threshold value.

[0031] If control unit 80 determines YES in step S104 of Fig. 2, it proceeds to step S105 of Fig. 2, where it operates main system 41 of steering device 40 and stops sub-system 42. At this time, control unit 80 stops sub-system 42 without determining the steering capability of sub-system 42, such as how much torque sub-steering motor 65 of sub-system 42 is generating.

[0032] As a result, as shown by the dashed line in Fig. 3, power is supplied from the capacitor 21 of the backup power supply 20 to the main system 41, causing the main system 41 to operate. On the other hand, since the sub-system 42 is stopped, power is not supplied from the capacitor 31 of the automatic operation backup power supply 30 to the sub-system 42. As shown by the dashed line in Fig. 3, the automatic operation backup power supply 30 supplies power only to the brake device 70, and it should be noted that the shaded areas in Fig. 3 indicate systems that are stopped.

[0033] As described above, the control unit 80 operates the main system 41 and stops the sub-system 42, thereby supplying power from the backup power source 20 to the main system 41 and stopping the power supply from the automatic operation backup power source 30 to the sub-system 42.

[0034] 2, it is determined that the sub-system 42 is in a stopped state and that power is not supplied from the capacitor 31 to the sub-system 42. Therefore, even if the sub-system 42 is not stopped, power is not supplied from the capacitor 31 to the sub-system 42, and the process ends without stopping the sub-system 42.

[0035] 4 is an explanatory diagram showing the state of power supply to the steering device 40 and the braking device 70 when the voltage of the main power supply 10 drops in a conventional vehicle power supply system 200. The dashed lines in FIG. 4 indicate the flow of power.

[0036] As shown in Fig. 4, in the vehicle power supply system 200, when the voltage of the main power supply 10 drops, power is supplied from the capacitor 31 to the brake device 70 and the sub-system 42 of the steering device 40. In addition, power is supplied from the capacitor 21 of the backup power supply 20 to the main system 41 of the steering device 40.

[0037] On the other hand, in the vehicle power supply system 100 of the embodiment, when the voltage of the main power supply 10 drops, power is supplied from the capacitor 31 to the brake device 70, and power is not supplied to the sub-system 42. Therefore, when the voltage of the main power supply 10 drops, the amount of power supplied from the capacitor 31 can be reduced. As a result, compared to the vehicle power supply system 200, the time during which power can be supplied from the automatic driving backup power supply 30 to the brake device 70 when the voltage of the main power supply 10 drops can be extended.

[0038] In the above description, the control unit 80 detects the voltage of the main power supply 10 using the voltage sensor 83, but this is not limiting. For example, the voltage of the main power supply 10 may be determined by acquiring the output voltage of the DC / DC converter 11 from the DC / DC converter 11.

[0039] In addition, in the above explanation, the control unit 80 adjusts the power supply between the backup power source 20 and the automatic operation backup power source 30 by operating the main system 41 and stopping the sub-system 42, but this is not limited to this.

[0040] For example, a cutoff switch may be placed between the backup power supply 20 and the main system 41, and between the automatic operation backup power supply 30 and the sub-system 42, and the power supply between the backup power supply 20 and the automatic operation backup power supply 30 may be adjusted by cutting off the power supply with the cutoff switch. [Explanation of symbols]

[0041] 10 main power supply, 11 DC / DC converter, 12 auxiliary battery, 20 backup power supply, 21, 31 capacitor, 30 backup power supply for autonomous driving, 40 steering device, 41 main system, 42 sub system, 51 main reaction motor, 52 main operation angle sensor, 53 main torque sensor, 54 main ECU, 55 main steering motor, 61 sub reaction motor, 62 sub operation angle sensor, 63 sub torque sensor, 64 sub ECU, 65 sub steering motor, 70 brake device, 80 control unit, 81 CPU, 82 memory, 83 voltage sensor, 85 autonomous driving interface box, 100, 200 vehicle power supply system.

Claims

1. a main power supply for supplying power to a main system and a sub-system of a steer-by-wire type steering device having two steering control systems, the main system and the sub-system; a backup power supply connected to the main system; an automatic operation backup power supply connected to the sub-system; A vehicle power supply system including: a control unit that adjusts power supply between the backup power supply and the automatic driving backup power supply; The control unit When the voltage of the main power supply drops below a predetermined threshold, supplying power from the backup power supply to the main system and stopping the supply of power from the automatic operation backup power supply to the sub-system; A vehicle power supply system comprising:

2. 2. The vehicle power supply system according to claim 1, the control unit adjusts the operations of the main system and the sub system, when the voltage of the main power supply drops below a predetermined threshold, operating the main system and stopping the operation of the sub-system, supplying power from the backup power supply to the main system, and stopping the power supply from the automatic operation backup power supply to the sub-system; A vehicle power supply system comprising:

3. 3. The vehicle power supply system according to claim 2, the automatic driving backup power supply is connected to the sub-system and a brake device, and supplies power to the brake device when the voltage of the main power supply drops below a predetermined threshold; A vehicle power supply system comprising:

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