Power supply system

Abstract

To provide a power supply system that, when a failure occurs in a main power supply, enables a sub power supply to properly supply electric power to a load.SOLUTION: A power supply system, which is loaded on a vehicle, comprises a first power supply that supplies electric power to a load, a second power supply that can back up the first power supply, a measuring part that measures the amount of discharged electric power from the second power supply, and a control part that controls a load to which electric power is supplied from the second power supply. When a failure occurs in the first power supply, the control part supplies electric power from the second power supply to a first load, until the amount of discharged electric power reaches a predetermined threshold, and switches a destination to which electric power is supplied from the second power supply to a second load, after the amount of discharged electric power reaches the predetermined threshold.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a power supply system that controls power supply from multiple power sources mounted on a vehicle. [Background technology]

[0002] Patent Document 1 discloses a control device that controls a sub-power source capable of backing up a main power source during autonomous driving. This control device describes that if it is determined that the sub-power source is capable of outputting the backup power required for evacuation driving during autonomous driving based on the state of the sub-power source estimated during the manual driving period after the ignition is turned on, it puts the vehicle into a state in which autonomous driving can be permitted. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-156228 A Summary of the Invention [Problem to be solved by the invention]

[0004] In general, the backup power of the sub-power source required during evacuation driving in the event of a main power supply failure during autonomous driving is defined in advance as the maximum current pattern (power) required during evacuation driving. However, during actual evacuation driving, there is a non-zero possibility that this defined backup power will be insufficient. In order to complete evacuation driving to the end even when this backup power is insufficient, it is possible to transfer authority from autonomous driving by the system to non-autonomous driving by the driver. When transferring authority in this way, switching control of the power supply to the appropriate load is required.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a power supply system that is capable of supplying power to an appropriate load from a sub-power supply in the event of a failure of the main power supply. [Means for solving the problem]

[0006] In order to solve the above problems, one aspect of the disclosed technology is a power supply system mounted on a vehicle, comprising: a first power supply that supplies power to a load; a second power supply that can back up the first power supply; a measurement unit that measures the discharge amount of the second power supply; and a control unit that controls a load to which the second power supply supplies power, wherein, when the first power supply fails, the control unit supplies power from the second power supply to the first load until the discharge amount reaches a predetermined threshold, and after the discharge amount reaches the predetermined threshold, the control unit switches the destination of the power supply from the second power supply to the second load. Effect of the Invention

[0007] According to the power supply system of the present disclosure, the discharge amount of the second power source is monitored and the load to which the power is supplied is switched, so that in the event of a power failure of the first power source, it is possible to supply power to an appropriate load according to the discharge amount of the second power source. [Brief description of the drawings]

[0008] [Figure 1] A functional block diagram of a power supply system and its peripheral parts according to an embodiment of the present disclosure. [Diagram 2] Flowchart of power supply control executed by the power supply system when power supply fails DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The power supply system according to the present disclosure has a function for measuring the discharge amount of a sub-power supply provided redundantly to back up a main power supply. This function makes it possible to appropriately switch the load to which power is supplied according to the discharge amount of the sub-power supply in the event of a failure of the main power supply, etc. Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0010] <Embodiment> [composition] Fig. 1 is a functional block diagram of a power supply system 100 and its peripheral units according to an embodiment of the present disclosure. The functional block illustrated in Fig. 1 includes 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 DC-DC 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.

[0011] A vehicle may be equipped with the power supply system 100, the multiple first loads 210, and the multiple second loads 220. The numbers of the first loads 210 and the second loads 220 equipped in the vehicle are not limited to the numbers shown in the figure.

[0012] The first power source 110 is a power supply source for supplying power to the first load 210 and the second load 220 via the DC-DC converter 120 and the control unit 150. The first power source 110 is a secondary battery configured to be chargeable and dischargeable, such as a lithium ion battery. An example of the first power source 110 in a vehicle is a high-voltage LiB (lithium ion battery).

[0013] The DCDC converter 120 is a voltage converter provided between the first power source 110 and the control unit 150, converting the input voltage of the first power source 110 into a voltage required for the first load 210 and the second load 220, and outputting the voltage to the first load 210 and the second load 220 via the control unit 150. This DCDC converter 120 is connected to a connection point between the first switch 151 and the third switch 153 of the control unit 150. For example, a step-down type DCDC converter that steps down the voltage of the first power source 110 and outputs it can be used as the DCDC converter 120.

[0014] The second power source 130 is a power supply source for supplying power to the first load 210 and the second load 220. The second power source 130 is a secondary battery configured to be chargeable and dischargeable, such as a lithium ion battery. The second power source 130 is connected to a connection point between a second switch 152 and a third switch 153 of the control unit 150. An example of the second power source 130 in a vehicle is an auxiliary LiB (lithium ion battery) that has a lower voltage than a high voltage LiB.

[0015] The measurement unit 140 is a component for measuring the state of the second power source 130, and is typically a microcomputer. The measurement unit 140 can measure the discharge amount [Ah], which is the amount of current discharged from the second power source 130 toward the first load 210 and the second load 220, as the state of the second power source 130. For this measurement, a detection device such as a voltage sensor or a current sensor is used. Note that, although a case where the measurement unit 140 is configured independently of the second power source 130 will be described, the measurement unit 140 may be built into the second power source 130.

[0016] The control unit 150 is a component (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.

[0017] 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 based on the control of the microcomputer 154. The first switch 151 is inserted between the first power source 110 and the first load 210 via the DC-DC converter 120.

[0018] 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 based on the control of the microcomputer 154. The second switch 152 is inserted between the second power supply 130 and the second load 220.

[0019] 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 based on the control of the microcomputer 154. The third switch 153 is inserted at a position where the multiple first loads 210 and the multiple second loads 220 are connected to each other.

[0020] The microcomputer 154 controls (switches) the conductive / cut-off states of the first switch 151, the second switch 152, and the third switch 153 based on the presence or absence of a failure in the first power supply 110 and the discharge amount of the second power supply 130. The occurrence of a power supply failure in the first power supply 110 can be detected (determined) based on information (current, voltage, etc.) output from the DCDC converter 120. In addition, the discharge amount of the second power supply 130 can be acquired from the measurement unit 140.

[0021] The first load 210 is a load that operates using the first power source 110 as a power source. The first load 210 includes a load (on-vehicle device) that realizes a function related to autonomous driving that requires a redundant power supply configuration.

[0022] The second load 220 is a load that can operate using the first power source 110 as a power source when the first power source 110 is normal, and can operate using either the first power source 110 or the second power source 130 as a power source when the first power source 110 fails. The second load 220 includes a load (on-vehicle device) that realizes a function related to non-automated driving.

[0023] [control] Next, the operation of the power supply system 100 according to this embodiment will be described with further reference to Fig. 2. Fig. 2 is a flowchart illustrating the procedure of power supply control during power failure, which is executed by the measurement unit 140 and the control unit 150 of the power supply system 100. The power supply control during power failure illustrated in Fig. 2 is started when the vehicle executes automatic driving.

[0024] (Step S201) The control unit 150 judges whether or not a failure of the first power source 110 has been detected. This judgment can be made based on the output of the DC-DC converter 120. The control unit 150 notifies the measurement unit 140 that a failure of the first power source 110 has been detected. If the control unit 150 detects a failure of the first power source 110 (Yes in step S201), the process proceeds to step S202.

[0025] (Step S202) The control unit 150 controls the conductive / cut-off states of the first switch 151, the second switch 152, and the third switch 153, respectively, to supply power from the second power source 130 to the first load 210. This control allows power to be continuously supplied to functions related to automatic driving, and system-led backup driving (specifically, evacuation driving) is started (automatic driving backup). When the control unit 150 has executed the supply of power from the second power source 130 to the first load 210, the process proceeds to step S203.

[0026] (Step S203) 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 an integrated value of the power supplied from the second power source 130 to the first load 210 after the start of the automatic driving backup. When the measurement unit 140 starts measuring the discharge amount of the second power source 130, the process proceeds to step S204.

[0027] (Step S204) The control unit 150 judges whether the discharge amount of the second power source 130 measured by the measurement unit 140 is equal to or greater than a predetermined threshold. This judgment is made in order to judge the timing for transferring driving authority for evacuation driving from the system to the driver. The predetermined threshold is set based on the maximum current pattern (current, time) required during evacuation driving. If the control unit 150 judges that the discharge amount of the second power source 130 is equal to or greater than the threshold (step S204, Yes), the process proceeds to step S205. When the discharge amount of the second power source 130 is equal to or greater than the threshold, the measurement unit 140 notifies the control unit 150. This notification may be made by, for example, turning on a predetermined flag (such as an automatic to non-automatic backup switching flag). On the other hand, if the control unit 150 judges that the discharge amount of the second power source 130 is not yet equal to or greater than the threshold (step S204, No), the process proceeds to step S203.

[0028] (Step S205) The control unit 150 controls the conductive / cut-off states of the first switch 151, the second switch 152, and the third switch 153, respectively, to supply power from the second power source 130 to the second load 220. That is, the control unit 150 switches the power supply destination from the second power source 130 from the first load 210 to the second load 220, and supplies power. This switching of the power supply destination can be performed, for example, by the control unit 150 detecting that the above-mentioned predetermined flag has been turned ON. By this control, the power supply destination is switched from a function related to automatic driving to a function related to non-automatic driving, driving authority is transferred from the system to the driver, and evacuation running led by the driver is started (non-automatic driving backup). When the control unit 150 supplies power from the second power source 130 to the second load 220, the power supply control at the time of the main power source failure is ended.

[0029] In FIG. 1, the first load 210 that supplies power from the second power source 130 during automatic driving backup is connected to the first power source 110. However, if the failure of the first power source 110 affects the control unit 150 through the DCDC converter 120, it is better to completely electrically separate the first power source 110 from the second power source 130 by cutting off the third switch 153. In this way, when the first power source 110 is completely electrically separated from the second power source 130 when the first power source 110 fails, it is possible to configure a load that realizes a function related to automatic driving that is the target of automatic driving backup as a part of the second load 220 side, and a load that realizes a function related to non-automatic driving that is the target of non-automatic driving backup as another part of the second load 220 side. In such a configuration, it is possible to appropriately switch the load that supplies power according to the discharge amount of the second power source 130 by appropriately controlling the conductive / cut-off state of the second switch 152.

[0030] <Actions and Effects> As described above, according to the power supply system 100 according to an embodiment of the present disclosure, when the first power supply 110 fails, the discharge amount of the second power supply 130 is monitored, and the power of the second power supply 130 is supplied to the first load 210 until the discharge amount of the second power supply 130 reaches a threshold value, and after the discharge amount of the second power supply 130 reaches the threshold value, control is performed to switch the power supply destination of the second power supply 130 from the first load 210 to the second load 220.

[0031] By this control, if the current consumed by the first load 210 during actual backup driving (evacuation driving) is less than the maximum current pattern defined by the automatic driving backup, the period during which power is supplied to the first load 210 can be extended. This can reduce the burden on the driver during the evacuation driving. Also, if the current consumed by the first load 210 during actual evacuation driving is more than the maximum current pattern defined by the automatic driving backup, the period during which power is supplied to the first load 210 can be shortened. This can be expected to allow the driver to complete the evacuation driving.

[0032] The above describes embodiments of the disclosed technology, but the present disclosure can be understood as not only a power supply system, but also 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 a power supply system, etc. [Industrial Applicability]

[0033] INDUSTRIAL APPLICABILITY The power supply system of the present disclosure can be used for power supply control of a vehicle or the like equipped with a first power supply that supplies power to a load and a second power supply that can back up the first power supply. [Explanation of symbols]

[0034] 100 Power System 110 1st power supply 120 DC-DC Converter 130 2nd power supply 140 Measurement section 150 Control section 151 First Switch 152 Second Switch 153 Third Switch 154 Microcomputer 210 1st load 220 2nd load

Claims

1. A power supply system mounted on a vehicle, a first power source for supplying power to a load; A second power source capable of backing up the first power source; A measurement unit that measures a discharge amount of the second power source; a control unit that controls the load to which the second power source supplies power, When the first power source fails, the control unit supplying power from the second power source to a first load until the discharge amount reaches a predetermined threshold; After the discharge amount reaches the predetermined threshold, a power supply destination of the second power supply is switched to a second load.

2. The first load is a load that realizes a function related to automatic driving, The second load is a load that realizes a function related to non-automated driving, 2. The power supply system according to claim 1, wherein the predetermined threshold is set based on a timing for transferring driving authority from the system to the driver in the event that the first power supply fails during autonomous driving of the vehicle.

3. 3. The power supply system according to claim 2, wherein the timing is a timing when the second power supply has enough electric power remaining to complete a predetermined evacuation run by the driver.

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