Power supply system

Abstract

A power supply system mounted in a vehicle is provided with: a first power supply for supplying power to a load; a second power supply capable of backing up the first power supply; a measurement unit that measures the amount of discharge of the second power source; and a control unit that controls the load of the power supply destination of the second power source, the control unit supplies the power of the second power source to the first load before the amount of discharge reaches a predetermined threshold value when the first power source has failed, and switches the power supply destination of the second power source to the second load after the amount of discharge reaches the predetermined threshold value.

Description

Technical Field

[0001] The present invention relates to a power supply system mounted on a vehicle that controls power supply based on multiple power sources. Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2020-156228 discloses a control device that controls a secondary power source capable of backing up a primary power source during autonomous driving. The following is described in the publication: If the above control device can determine that the secondary power source can output the backup power required during the avoidance driving in autonomous driving based on the state of the secondary power source inferred during the manual driving period after the ignition is turned on, it is set to a state where autonomous driving is permitted. Summary of the Invention

[0003] Generally, the backup power of the secondary power source required during the avoidance driving when the primary power source fails during autonomous driving is predefined in the maximum current mode (power) required during the avoidance driving. However, in actual avoidance driving, the possibility that the predefined backup power is insufficient is not zero. In order to complete the avoidance driving to the end even when the backup power becomes insufficient, it is considered to transfer the authority from system-based autonomous driving to driver-based non-autonomous driving. At the time of this authority transfer, it is necessary to control the switching of the power supply to an appropriate load.

[0004] The present invention provides a power supply system that can supply power from a secondary power source to an appropriate load when the primary power source fails.

[0005] One aspect of the technology of the present invention is a power supply system mounted on a vehicle, which includes: a first power source that supplies power to a load; a second power source that can back up the first power source; a measurement unit that measures the discharge amount of the second power source; and a control unit that controls the load to which the second power source supplies power. When the first power source fails, the control unit supplies the power of the second power source to a first load before the discharge amount reaches a specified threshold, and switches the power supply destination of the second power source to a second load after the discharge amount reaches the specified threshold.

[0006] According to the power supply system of the present invention described above, the discharge amount of the second power source is monitored and the load of the power supply destination is switched. Therefore, when the first power source fails, power can be supplied to an appropriate load corresponding to the discharge amount of the second power source. Brief Description of the Drawings

[0007] Hereinafter, with reference to the drawings, the features, advantages, and technical and industrial significance of the exemplary embodiments of the present invention will be described. In the drawings, the same reference numerals denote the same elements, and:

[0008] Figure 1 is a functional block diagram of a power supply system and its peripheral parts according to an embodiment of the present invention.

[0009] Figure 2 is a processing flowchart of power supply control during a power failure executed by the power supply system. Detailed Embodiment

[0010] The power supply system based on the present invention has a function of measuring the discharge amount of a secondary power supply redundantly provided for backup of the main power supply. With this function, in the case of a failure of the main power supply or the like, it is possible to appropriately switch the load to which power is to be supplied according to the discharge amount of the secondary power supply.

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0012] Embodiment

[0013] Structure

[0014] Figure 1 is a functional block diagram of a power supply system 100 and its peripheral parts according to an embodiment of the present invention. Figure 1 The functional blocks illustrated in it include a power supply system 100, a plurality of first loads 210, and a plurality of second loads 220. The power supply system 100 includes a first power supply 110, a DCDC converter (DDC) 120, a second power supply 130, a measurement unit 140, and a control unit 150. The control unit 150 includes a plurality of first switches (SW) 151, a plurality of second switches (SW) 152, a third switch (SW) 153, and a microcomputer 154.

[0015] The power supply system 100, the plurality of first loads 210, and the plurality of second loads 220 can be mounted on a vehicle. In addition, the number of the first loads 210 and the second loads 220 mounted on the vehicle is not limited to the number shown in the figure.

[0016] The first power supply 110 is a power supply source for supplying power to the first load 210 or the second load 220 via the DCDC converter 120 and the control unit 150. The first power supply 110 is a secondary battery configured to be chargeable and dischargeable, such as a lithium-ion battery or the like. As the first power supply 110 in a vehicle, a high-voltage LiB (lithium-ion battery) can be exemplified.

[0017] The DCDC converter 120 is provided between the first power supply 110 and the control unit 150. The DCDC converter 120 is a voltage converter that converts the voltage of the input first power supply 110 into the voltages required by the first load 210 and the second load 220 and outputs them to the first load 210 and the second load 220 via the control unit 150. The DCDC converter 120 is connected to the connection points of the first switch 151 and the third switch 153 of the control unit 150. In the DCDC converter 120, for example, a step-down DCDC converter that steps down the voltage of the first power supply 110 and outputs it can be used.

[0018] The second power supply 130 is a power supply source for supplying power to the first load 210 or the second load 220. The second power supply 130 is a secondary battery configured to be chargeable and dischargeable, such as a lithium-ion battery or the like. The second power supply 130 is connected to the connection points of the second switch 152 and the third switch 153 of the control unit 150. As the second power supply 130 in the vehicle, an auxiliary LiB (lithium-ion battery) with a lower voltage than the high-voltage LiB can be exemplified.

[0019] The measurement unit 140 is a structure for measuring the state of the second power supply 130, usually a microcomputer. The measurement unit 140 can measure the amount of discharge [Ah], which is the amount of current released from the second power supply 130 to the first load 210 or the second load 220, as the state of the second power supply 130. In this measurement, detection devices such as a voltage sensor or a current sensor can be used. In addition, although the case where the measurement unit 140 is configured independently of the second power supply 130 has been described, it may also be built into the second power supply 130.

[0020] The control unit 150 is a structure (B-DC) for controlling the state of power supply to the first load 210 and the second load 220 in the power supply system 100.

[0021] The first switch 151 is a switching element (such as a semiconductor switch) that can switch between an electrically conductive state and a cut-off state according to the control of the microcomputer 154. The first switch 151 is inserted between the first power supply 110 and the first load 210 via the DCDC converter 120, respectively.

[0022] The second switch 152 is a switching element (such as a semiconductor switch) that can switch between an electrically conductive state and a cut-off state according to the control of the microcomputer 154. The second switch 152 is inserted between the second power supply 130 and the second load 220, respectively.

[0023] The third switch 153 is a switching element (such as a semiconductor switch) that can switch between an electrically conductive state and a cut-off state according to the control of the microcomputer 154. The third switch 153 is inserted at a position connecting a plurality of first loads 210 and a plurality of second loads 220.

[0024] The microcomputer 154 controls (switches) the on / off states of the first switch 151, the second switch 152, and the third switch 153 according to whether there is a fault in the first power supply 110 and the discharge amount of the second power supply 130. The occurrence of a power supply fault in the first power supply 110 can be detected (judged) based on the information (current, voltage, etc.) output from the DCDC converter 120. Also, the discharge amount of the second power supply 130 can be obtained from the measurement unit 140.

[0025] The first load 210 is a load that operates using the first power supply 110 as a power source. This first load 210 may include loads (in-vehicle devices) that implement functions related to autonomous driving that require a redundant power supply structure.

[0026] The second load 220 is a load that can operate using the first power supply 110 as a power source when the first power supply 110 is normal, and can operate using the first power supply 110 or the second power supply 130 as a power source when the first power supply 110 fails. This second load 220 may include loads (in-vehicle devices) that implement functions related to non-autonomous driving.

[0027] Control

[0028] Next, with further reference to Figure 2 , the operation of the power supply system 100 according to the present embodiment will be described. Figure 2 is a flowchart showing the processing sequence of power supply control during a power supply fault performed by the measurement unit 140 and the control unit 150 of the power supply system 100. The Figure 2 power supply control during a power supply fault illustrated therein starts when the vehicle performs autonomous driving.

[0029] S201

[0030] The control unit 150 determines whether a fault in the first power supply 110 is detected. This determination can be made based on the output of the DCDC converter 120. When a fault in the first power supply 110 is detected, the control unit 150 notifies the measurement unit 140. If a fault in the first power supply 110 is detected by the control unit 150 (S201, Yes), the process proceeds to S202.

[0031] S202

[0032] The control unit 150 supplies power from the second power source 130 to the first load 210 by respectively controlling the on / off states of the first switch 151, the second switch 152, and the third switch 153. Through this control, the power supply to the functions related to autonomous driving is continued, and the system-led reverse driving (specifically, avoidance driving) (autonomous driving backup) is started. If the control unit 150 executes the power supply from the second power source 130 to the first load 210, the process proceeds to S203.

[0033] S203

[0034] The measurement unit 140 starts measuring the discharge amount of the second power source 130. The discharge amount measured by the measurement unit 140 is the cumulative value of the power supplied from the second power source 130 to the first load 210 after starting the autonomous driving backup. If the measurement unit 140 starts measuring the discharge amount of the second power source 130, the process proceeds to S204.

[0035] S204

[0036] The control unit 150 determines whether the discharge amount of the second power source 130 measured by the measurement unit 140 has reached a specified threshold or more. This determination is made to judge the timing of transferring the driving authority of the avoidance driving from the system to the driver. And the specified threshold is set according to the maximum current mode (current, time) required during the avoidance driving. When the control unit 150 determines that the discharge amount of the second power source 130 has reached the threshold or more (S204, Yes), the process proceeds to S205. If the discharge amount of the second power source 130 has reached the threshold or more, the measurement unit 140 notifies the control unit 150. This notification can be made, for example, by setting a specified flag (automatic → non-automatic backup switching flag, etc.) to ON. On the other hand, when the control unit 150 determines that the discharge amount of the second power source 130 has not reached the threshold or more (S204, No), the process proceeds to S203.

[0037] S205

[0038] The control unit 150 supplies power from the second power source 130 to the second load 220 by respectively controlling the on / off states of the first switch 151, the second switch 152, and the third switch 153. That is, the control unit 150 switches the power supply destination from the first load 210 to the second load 220 from the second power source 130 and performs power supply. The switching of the power supply destination can be performed, for example, when the control unit 150 detects that the above-mentioned specified flag becomes ON. Through this control, the power supply destination is switched from a function related to autonomous driving to a function related to non-autonomous driving, and the driving authority is transferred from the system to the driver, and the avoidance driving based on the driver's initiative (non-autonomous driving backup) is started. If the control unit 150 performs power supply from the second power source 130 to the second load 220, the power supply control at the time of this power failure is ended.

[0039] In addition, in Figure 1 it has been described that the first load 210 that receives power supply from the second power source 130 during autonomous driving backup is connected to the first power source 110 side. However, in the case where the influence caused by the failure of the first power source 110 spreads to the control unit 150 through the DCDC converter 120, it is preferable to cut off the third switch 153 and electrically isolate the first power source 110 from the second power source 130 completely. As described above, in the case of electrically isolating the first power source 110 from the second power source 130 completely when the first power source 110 fails, it can be considered that the load that realizes the function related to autonomous driving that is the object of autonomous driving backup is configured as a part on the second load 220 side, and the load that realizes the function related to non-autonomous driving that is the object of non-autonomous driving backup is configured as another part on the second load 220 side. In such a configuration, it is possible to appropriately switch the load to which power is to be supplied corresponding to the discharge amount of the second power source 130 by appropriately controlling the on / off state of the second switch 152.

[0040] Operation and Effect

[0041] As described above, according to the power supply system 100 according to an embodiment of the present invention, when the first power source 110 fails, the discharge amount of the second power source 130 is monitored. Moreover, before the discharge amount of the second power source 130 reaches the threshold value, the second power source 130 supplies power to the first load 210. Then, after the discharge amount of the second power source 130 reaches the threshold value, control is performed to switch the power supply destination of the second power source 130 from the first load 210 to the second load 220.

[0042] With this control, if the current consumed by the first load 210 during actual reverse driving (retreat driving) is less than the maximum current mode defined for autonomous driving backup, the period of supplying power to the first load 210 can be extended. Thereby, the burden on the driver for reverse driving can be reduced. Also, during actual reverse driving, if the current consumed by the first load 210 is more than the maximum current mode defined for autonomous driving backup, the period of supplying power to the first load 210 can be shortened. Thereby, it can be expected that the driver will complete the reverse driving.

[0043] As described above, embodiments of the technology of the present invention have been described, but the present invention is not limited to the power supply system, and can also be understood as a control method performed by the power supply system, a program for the control method, a computer-readable non-transitory storage medium storing the program, a vehicle equipped with the power supply system, etc.

[0044] The power supply system of the present invention can be used for power control of vehicles, etc., equipped with a first power supply for supplying power to a load and a second power supply capable of backing up the first power supply.

Claims

1. A power supply system mounted on a vehicle, the power supply system comprising: a first power source that supplies power to a load; a second power source capable of backing up the first power source; a measuring unit configured to measure a discharge amount of the second power source; and a control unit that controls the load to which the power of the second power source is supplied, When the first power supply fails, the control unit Before the discharge amount reaches a predetermined threshold, the electric power of the second power supply is supplied to the first load, After the discharge amount reaches the predetermined threshold value, the power supply destination of the second power supply is switched to a second load.

2. The power supply system according to claim 1, characterized in that: The first load is a load that realizes a function related to autonomous driving. The second load is a load that implements a function related to non-automatic driving. The predetermined threshold value is set based on a timing at which the driving authority is transferred from the system to the driver when the first power supply fails while the vehicle is automatically driving.

3. The power supply system according to claim 2, characterized in that: The timing is the timing at which electric power sufficient to complete the predetermined evacuation travel by the driver remains in the second power supply.

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