Power supply control device and control method

Abstract

To provide a power supply control device and a control method with which it is possible to quickly execute backup control after it is inspected whether or not backup control can be executed.SOLUTION: The power supply control device pertaining to an embodiment comprises a first system, a second system, a plurality of load switches, and a control unit. The first system is capable of supplying electric power from a first power supply to a first load. The second system is capable of supplying electric power from a second power supply to a load group having a second load and a third load whose electric power consumption is smaller than that of the second load. A load switch is capable of switching electric power supply to each load in the load group. When the occurrence of a ground fault in the first system is detected, the control unit controls the load switch so that backup control by the second system is executed by electric power supply from the second power supply. When inspecting whether or not the backup control is executable, the control unit connects a corresponding load switch to the third load in the load group and executes inspection.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a technology for supplying power from multiple systems. [Background technology]

[0002] BACKGROUND ART Conventionally, a power supply system is known in which, when an abnormality occurs in one of a plurality of power systems, power is supplied to a backup load from another power system (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-182864 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the power supply system does not take into consideration a test method for testing whether backup control using a backup load is possible. As a result, after the test, the storage capacity of the power supply that supplies power from another power system may decrease, and the time during which backup control cannot be performed may become long until the power supply is recharged after the test.

[0005] The present invention has been made in consideration of the above, and aims to provide a power supply control device and a control method that enable backup control to be quickly performed after checking whether backup control can be performed. [Means for solving the problem]

[0006] A power supply control device according to one aspect of the embodiment includes a first system, a second system, a plurality of load switches, and a control unit. The first system is capable of supplying power from a first power source to a first load. The second system is capable of supplying power from the second power source to a load group having a second load and a third load consuming less power than the second load. The load switches are capable of switching the power supply to each load in the load group. When a ground fault is detected in the first system, the control unit controls the load switches so that backup control by the second system is performed by power supply from the second power source. When checking whether backup control is possible, the control unit connects the load switch corresponding to the third load in the load group and performs the check. [Effects of the Invention]

[0007] According to one aspect of the embodiment, after checking whether backup control is executable or not, backup control can be quickly executed. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an explanatory diagram illustrating an example of the configuration of a power supply control device according to the first embodiment. [Figure 2] FIG. 2 is a diagram showing voltage changes when backup control is performed by the second power supply. [Figure 3] FIG. 3 is a diagram illustrating power supply by the first power source. [Figure 4] FIG. 4 is a diagram showing power supply when a ground fault occurs in the first system. [Figure 5] FIG. 5 is a diagram illustrating power supply when a check is performed to see whether backup control by the second power source can be performed. [Figure 6] FIG. 6 is a diagram showing power supply when a ground fault occurs in the second system. [Figure 7] FIG. 7 is a flowchart illustrating the inspection process according to the first embodiment. [Figure 8] FIG. 8 is a diagram illustrating an example of the configuration of a power supply control device according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of a power supply control device and a control method will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments described below. The following description will be given using an example of a power supply control device that is installed in a vehicle with an autonomous driving function and supplies power to a load, but the power supply control device according to the embodiment may also be installed in a vehicle that does not have an autonomous driving function.

[0010] In addition, although the following description will be given of a case where the vehicle in which the power supply control device is installed is an electric vehicle or a hybrid vehicle, the vehicle in which the power supply control device is installed may also be an engine vehicle that runs on an internal combustion engine.

[0011] In addition, the power supply control device of the embodiment may be installed in any device that has a first power supply which is a main power supply and a second power supply which is an auxiliary power supply, and that backs up the first power supply with the second power supply in the event of a power failure in the first power supply.

[0012] (First embodiment) Fig. 1 is an explanatory diagram showing an example of the configuration of a power supply control device 1 according to a first embodiment. As shown in Fig. 1, the power supply control device 1 according to the first embodiment is connected to a first power source 10, a first load 101, a general load 102, a group of loads 110, an automatic operation control device 120, and a start switch 130. The power supply control device 1 includes a first system 200 and a second system 210. The first system 200 can supply power from the first power source 10 to the first load 101 and the general load 102. The second system 210 can supply power from a second power source 20, which will be described later, to the group of loads 110.

[0013] The first power source 10 includes a DC / DC converter (hereinafter referred to as "DC / DC 11") and a lead battery (hereinafter referred to as "PbB 12"). The battery of the first power source 10 may be any secondary battery other than PbB 12.

[0014] The DC / DC converter 11 is connected to a generator and a high-voltage battery having a higher voltage than the PbB 12, and steps down the voltages of the generator and the high-voltage battery and outputs the stepped-down voltage to the first system 200. The generator is, for example, an alternator that converts the kinetic energy of a running vehicle into electricity to generate power. The high-voltage battery is, for example, a battery for driving the vehicle that is installed in an electric vehicle or a hybrid vehicle.

[0015] When the first power supply 10 is installed in an engine vehicle, an alternator (generator) is provided instead of the DC / DC 11. The DC / DC 11 charges the PbB 12, supplies power to the first load 101 and the general load 102, supplies power to the load group 110, and charges the second power supply 20, which will be described later.

[0016] The first load 101 includes a load for autonomous driving, such as a steering motor, an electric brake device, an in-vehicle camera, and a radar, which operate during autonomous driving.

[0017] The general load 102 does not include a load for automatic driving, and includes, for example, a display, an air conditioner, an audio device, a video device, various lights, and the like.

[0018] The group of loads 110 has the same function as the first load 101. That is, the group of loads 110 includes a load for automatic driving. The group of loads 110 includes a second load 111 and a third load 112.

[0019] The second load 111 is a load for automatic driving that has an actuator that operates during automatic driving. The second load 111 is, for example, a load in a drive system that includes a steering motor, an electric brake device, etc. Since a relatively large amount of power is required to drive an actuator, the power consumption of the second load 111 is larger than that of a load that does not have an actuator.

[0020] The third load 112 is a load for autonomous driving that does not have an actuator that operates during autonomous driving. The third load 112 is, for example, a recognition system load that includes an in-vehicle camera, radar, etc. The third load 112 may be further divided into multiple loads. Since the third load 112 does not have an actuator, it consumes less power than the second load 111.

[0021] The first load 101, the general load 102, and the load group 110 operate using power supplied from the power supply control device 1.

[0022] The automatic driving control device 120 is a device that operates at least one of the first load 101 and the group of loads 110 to perform automatic driving control of the vehicle. The automatic driving control device 120 can operate either the first load 101 or the group of loads 110 to perform fail-safe control of the automatic driving control (hereinafter referred to as "backup control"). When a ground fault occurs in the first system 200 or the second system 210, the automatic driving control device 120 performs backup control using a system in which the ground fault does not occur. The backup control is a control that automatically drives the vehicle to evacuate to a safe place. In addition to a ground fault, the backup control is also performed when a power supply failure occurs in which power cannot be supplied from the first system 200 or the second system 210. An example in which a ground fault occurs will be described below, but the processing described below can also be applied as appropriate to a case in which a power supply failure occurs.

[0023] The start switch 130 is a switch that switches the power supply system ON or OFF, and may be an ignition switch or an ACC (accessory) switch.

[0024] The power supply control device 1 includes a second power supply 20, an inter-system switch 41, a battery switch 42, a plurality of load switches 43, 44, a first voltage sensor 50, a second voltage sensor 51, and a control unit 60.

[0025] The second power source 20 is a backup power source in case the first power source 10 is unable to supply power. The second power source 20 includes a lithium ion battery (hereinafter referred to as "LiB21"). The battery of the second power source 20 may be any secondary battery other than the LiB21. The second power source 20 is provided with a measuring device. The measuring device acquires voltage information of the LiB21. That is, the voltage of the LiB21 is measured by the measuring device.

[0026] The inter-system switch 41 is provided on the inter-system line 220 that connects the first system 200 and the second system 210. The inter-system switch 41 is a switch that can connect or disconnect the first system 200 and the second system 210. When the inter-system switch 41 is turned ON, both ends of the inter-system switch 41 are electrically connected. When the inter-system switch 41 is turned OFF, both ends of the inter-system switch 41 are electrically disconnected. The same applies to the other switches.

[0027] The battery switch 42 is a switch that can connect or disconnect the LiB 21 and the second system 210.

[0028] The plurality of load switches 43 and 44 are switches that can switch the power supply to the second load 111 and the third load 112 of the load group 110, respectively. The plurality of load switches 43 and 44 include a first switch 43 and a second switch 44.

[0029] The first switch 43 is provided in the second system 210. The first switch 43 is provided corresponding to the second load 111. The first switch 43 is a switch that switches whether or not to supply power to the second load 111. The first switch 43 connects or disconnects the second load 111 and the second system 210.

[0030] The second switch 44 is provided in the second system 210. The second switch 44 is provided corresponding to the third load 112. The second switch 44 is a switch that switches whether or not to supply power to the third load 112. The second switch 44 connects or disconnects the third load 112 and the second system 210.

[0031] The first voltage sensor 50 is provided in the first system 200, detects the voltage of the first system 200, and outputs the detection result to the control unit 60. The second voltage sensor 51 is provided in the second system 210, detects the voltage of the second system 210, and outputs the detection result to the control unit 60.

[0032] The control unit 60 includes a microcomputer having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc., and various other circuits. The control unit 60 may also be configured with hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0033] The control unit 60 includes a detection unit 61 that functions when the CPU executes a program stored in the ROM using the RAM as a work area, and a switch setting unit 62, and controls the operation of the power supply control device 1. The control unit 60 operates by receiving power from the first power source 10 and the second power source 20. In other words, the control unit 60 can operate by receiving power from the first power source 10 or the second power source 20. The functions of the detection unit 61 and the switch setting unit 62 may be divided into multiple units.

[0034] When a ground fault is detected in the first system 200, the control unit 60 controls the first switch 43 and the second switch 44 so that backup control by the second system 210 is performed by power supply from the second power source 20. When checking whether backup control is possible, the control unit 60 turns on the second switch 44 corresponding to the third load 112, which consumes less power among the load group 110, and performs the check.

[0035] The detection unit 61 detects a ground fault in the first system 200 or the second system 210 based on the detection results input from the first voltage sensor 50 and the second voltage sensor 51 .

[0036] The detection unit 61 determines whether the voltage detected by the first voltage sensor 50 is within a normal range when the inter-system switch 41 is ON and in a normal state. The normal range is the range indicated by the voltage detected by the first voltage sensor 50 when no ground fault occurs in the first system 200. For example, the normal range is the range in which the voltage detected by the first voltage sensor 50 is equal to or greater than a preset voltage threshold value.

[0037] In a normal state, if the voltage detected by the first voltage sensor 50 is not within the normal range, for example, if the voltage is lower than the voltage threshold, the detection unit 61 detects that a ground fault has occurred in the first system 200.

[0038] In a normal state, when the voltage detected by the first voltage sensor 50 is within a normal range, the detection unit 61 detects that no ground fault has occurred in the first system 200.

[0039] The detector 61 can detect the occurrence of a ground fault in the second system 210 based on the voltage detected by the second voltage sensor 51 in a normal state.

[0040] When the detection unit 61 detects a ground fault in the first system 200 or the second system 210, it notifies the automatic driving control device 120 of that fact. When the detection unit 61 detects a ground fault in the first system 200 or the second system 210, it may notify the automatic driving control device 120 of a state in which automatic driving is impossible. When the detection unit 61 does not detect a ground fault in the first system 200 or the second system 210, it may notify the automatic driving control device 120 of a state in which automatic driving is possible.

[0041] The detection unit 61 acquires voltage information of the LiB 21 from a measurement device of the second power source 20 via the line L, and detects the voltage of the LiB 21. The detection unit 61 detects the state of charge (SOC) of the second power source 20 based on the voltage of the LiB 21. Note that the detection unit 61 may acquire current information and temperature information in addition to the voltage information, and detect the state of charge of the second power source 20 using the current information, etc.

[0042] When the start switch 130 is turned ON, the detection unit 61 performs a background check to determine whether or not backup control by the second power source 20 can be executed. Note that the detection unit 61 may also perform the check when the start switch 130 is turned OFF.

[0043] The detection unit 61 performs the inspection in a state where the second switch 44 corresponding to the third load 112 of the load group 110 is connected.

[0044] In the test, power is supplied from the second power source 20 to the third load 112 for a predetermined time while the inter-system switch 41 and the first switch 43 are OFF and the battery switch 42 and the second switch 44 are ON.

[0045] The predetermined time is a time set in advance, and is the time for which the startup process is performed after the start switch 130 is turned on. The predetermined time is a few seconds, such as 2 seconds or 3 seconds.

[0046] The detection unit 61 determines whether a predetermined time has elapsed since the start switch 130 was turned on. The detection unit 61 performs an inspection based on the voltage of the LiB 21 after the predetermined time has elapsed. Note that the voltage of the LiB 21 after the predetermined time has elapsed is the voltage of the LiB 21 immediately after the predetermined time has elapsed.

[0047] The detection unit 61 determines whether the voltage of the LiB 21 after the predetermined time has elapsed is equal to or greater than a predetermined voltage. If the voltage of the LiB 21 after the predetermined time has elapsed is equal to or greater than the predetermined voltage, the detection unit 61 determines that backup control by the second power source 20 can be performed. If the voltage of the LiB 21 after the predetermined time has elapsed is less than the predetermined voltage, the detection unit 61 determines that backup control by the second power source 20 cannot be performed.

[0048] The predetermined voltage is a voltage that is set in advance. The predetermined voltage is set to a lower limit voltage after backup control by the second power source 20 is executed during the evacuation time. The evacuation time is a predetermined time that is required for the vehicle to evacuate to a safe place by backup control by the second power source 20. The evacuation time is set based on experimental results, calculations, simulation results, etc.

[0049] The lower limit voltage is the voltage of the LiB 21 after the backup control by the second power source 20 has been performed for the evacuation time and the vehicle has been evacuated to a safe place. In other words, if the voltage of the LiB 21 is equal to or higher than the lower limit voltage after the evacuation time has elapsed since the backup control by the second power source 20 was started, this means that the vehicle has been evacuated to a safe place.

[0050] Therefore, by comparing the voltage change of LiB21, which becomes the lower limit voltage after the evacuation time (hereinafter referred to as "lower limit voltage change of LiB21"), with the voltage change when power is supplied from the second power source 20 to the load group 110, the feasibility of backup control by the second power source 20 can be determined.

[0051] Specifically, if the voltage of the LiB 21 at a certain time when power is supplied from the second power source 20 to the load group 110 is equal to or greater than the voltage at a certain time in the lower limit voltage change of the LiB 21, backup control by the second power source 20 can be performed. On the other hand, if the voltage of the LiB 21 at a certain time when power is supplied from the second power source 20 to the load group 110 is less than the voltage at a certain time in the lower limit voltage change of the LiB 21, backup control by the second power source 20 cannot be performed.

[0052] Regarding the change in the lower limit voltage of the LiB21, the voltage change of the LiB21 due to power consumption by the third load 112 (hereinafter referred to as "voltage change due to the third load 112") is shown, for example, as in FIG. 2. The lower limit voltage change of the LiB21 and the voltage change due to the third load 112 are obtained by experiments, etc. FIG. 2 is a diagram showing voltage changes when backup control is performed by the second power source 20. In FIG. 2, backup control by the second power source 20 is started at time t0. Furthermore, at time t1, the vehicle is evacuated to a safe place.

[0053] Similarly, by comparing the voltage change caused by the third load 112 with the test voltage change when the start switch 130 is turned OFF (hereinafter referred to as the "test voltage change"), the feasibility of backup control by the second power source 20 can be determined.

[0054] Specifically, if the voltage in the voltage change during the inspection is equal to or greater than the voltage of the voltage change caused by the third load 112, backup control by the second power supply 20 can be performed. On the other hand, if the voltage in the voltage change during the inspection is less than the voltage of the voltage change caused by the third load 112, backup control cannot be performed.

[0055] In this way, the feasibility of backup control by the second power source 20 can be determined based on the power consumption in the third load 112.

[0056] 2, the predetermined voltage is the voltage of the LiB 21 for a predetermined time in the voltage change caused by the third load 112. The predetermined voltage is set based on experimental results, calculations, simulation results, and the like.

[0057] The detection unit 61 may determine whether or not backup control by the second power supply 20 can be performed based on a voltage difference of the LiB 21 after a predetermined time has elapsed. The voltage difference is the difference between the voltage of the LiB 21 during the voltage change in the test and the voltage of the LiB 21 during the voltage change caused by the third load 112.

[0058] When backup control by the second power source 20 can be performed, the voltage of Lib21 during the voltage change during the test is equal to or greater than the voltage of LiB21 during the voltage change due to the third load 112. Therefore, when backup control by the second power source 20 can be performed, the voltage difference of LiB21 is equal to or greater than a predetermined amount. The predetermined amount is a value that is set in advance, for example, "0." When backup control by the second power source 20 cannot be performed, the voltage of Lib21 during the voltage change during the test is less than the voltage of LiB21 during the voltage change due to the third load 112. Therefore, the voltage difference of LiB21 is less than the predetermined amount (i.e., negative).

[0059] If the voltage difference of the LiB 21 after the predetermined time has elapsed is equal to or greater than the predetermined amount, the detection unit 61 determines that backup control by the second power source 20 can be performed. If the voltage difference of the LiB 21 after the predetermined time has elapsed is less than the predetermined amount, the detection unit 61 determines that backup control by the second power source 20 cannot be performed.

[0060] Furthermore, the detection unit 61 may determine whether or not backup control by the second power source 20 is executable based on the amount of voltage drop, which is the difference between the voltage of the LiB 21 at the start of the inspection and the voltage of the LiB 21 after a predetermined time has elapsed, i.e., the amount of voltage drop of the LiB 21 during the predetermined time during the inspection. In this case, the detection unit 61 determines that backup control by the second power source 20 is executable if the amount of voltage drop is less than a predetermined amount. Furthermore, the detection unit 61 determines that backup control by the second power source 20 is not executable if the amount of voltage drop is equal to or greater than a predetermined amount.

[0061] The switch setting unit 62 sets and switches each of the switches 41 to 44 to ON or OFF. When no ground fault occurs in the first system 200 and the second system 210, the switch setting unit 62 turns on the inter-system switch 41, the first switch 43, and the second switch 44. As a result, as shown in FIG. 3, power is supplied from the first power source 10 to the first load 101 and the general load 102 via the first system 200. FIG. 3 is a diagram showing power supply by the first power source 10. Furthermore, power is supplied from the first power source 10 to the second load 111 and the third load 112 of the load group 110 via the first system 200, the inter-system line 220, and the second system 210.

[0062] When the second power source 20 is being charged, the switch setting unit 62 also turns on the battery switch 42. This causes power to be supplied from the first power source 10 to the LiB 21 of the second power source 20, charging the LiB 21. When the LiB 21 of the second power source 20 is not being charged, the switch setting unit 62 turns off the battery switch 42.

[0063] When a ground fault occurs in the first system 200, the switch setting unit 62 turns off the inter-system switch 41. Furthermore, the switch setting unit 62 turns on the battery switch 42, the first switch 43, and the second switch 44. As a result, power is supplied from the second power source 20 to the load group 110 via the second system 210, as shown in Fig. 4. Fig. 4 is a diagram showing power supply when a ground fault occurs in the first system 200.

[0064] When checking whether backup control by the second power source 20 can be performed, the switch setting unit 62 turns OFF the inter-system switch 41 and the first switch 43. Furthermore, the switch setting unit 62 turns ON the battery switch 42 and the second switch 44. As a result, as shown in Fig. 5, power is supplied from the second power source 20 to the third load 112 via the second system 210. Note that, because the first switch 43 is OFF, power is not supplied to the second load 111. Fig. 5 is a diagram showing power supply when checking whether backup control by the second power source 20 can be performed.

[0065] When a ground fault occurs in the second system 210, the switch setting unit 62 turns off the inter-system switch 41, the battery switch 42, the first switch 43, and the second switch 44. As a result, power is supplied from the first power source 10 to the first load 101 and the general load 102 via the first system 200, as shown in Fig. 6. Fig. 6 is a diagram showing power supply when a ground fault occurs in the second system 210.

[0066] Next, the inspection process according to the embodiment will be described with reference to Fig. 7. Fig. 7 is a flowchart illustrating the inspection process according to the first embodiment. The inspection process is executed when the start switch 130 is turned on.

[0067] The power supply control device 1 sets each of the switches 41 to 44 (S100). Specifically, the power supply control device 1 turns the inter-system switch 41 and the first switch 43 OFF, and turns the battery switch 42 and the second switch 44 ON.

[0068] The power supply control device 1 determines whether a predetermined time has elapsed since the start switch 130 was turned on (S101). That is, the power supply control device 1 determines whether the start switch 130 was turned on and startup processing was performed. If the predetermined time has not elapsed (S101: No), the power supply control device 1 repeats the determination until the predetermined time has elapsed (S101).

[0069] When a predetermined time has elapsed since the start switch 130 was turned on (S101: Yes), the power supply control device 1 detects the voltage of the LiB 21 (S102). That is, the power supply control device 1 detects the voltage of the LiB 21 that has dropped due to the power supply from the second power source 20 to the third load 112.

[0070] The power supply control device 1 determines whether the detected voltage of the LiB 21 is equal to or higher than a predetermined voltage (S103). If the voltage of the LiB 21 is equal to or higher than the predetermined voltage (S103: Yes), the power supply control device determines that backup control by the second power supply 20 can be performed (S104).

[0071] If the voltage of the LiB 21 is lower than the predetermined voltage (S103: No), the power supply control device 1 determines that backup control by the second power supply 20 is not executable (S105).

[0072] When checking whether backup control is executable, a method of supplying power from the second power source 20 to the second load 111 and the third load 112 of the load group 110 may be considered, similar to actual backup control.

[0073] However, when power is supplied from the second power source 20 to the second load 111 and the third load 112, the state of charge of the second power source 20 after the inspection drops significantly. Therefore, backup control by the second power source 20 cannot be performed until the second power source 20 is recharged.

[0074] In contrast, the power supply control device 1 according to the embodiment includes a first system 200, a second system 210, a first switch 43, and a second switch 44 (plurality of load switches), and a control unit 60. The first system 200 is capable of supplying power from the first power source 10 to a first load 101. The second system 210 is capable of supplying power from the second power source 20 to a group of loads 110 including a second load 111 and a third load 112 that consumes less power than the second load 111. The first switch 43 and the second switch 44 are capable of switching the power supply to the second load 111 and the third load 112 of the group of loads 110, respectively. When a ground fault is detected in the first system 200, the control unit 60 controls the first switch 43 and the second switch 44 so that the backup control by the second system 210 is performed by the power supply from the second power source 20. When checking whether backup control is possible, the control unit 60 connects the second switch 44 corresponding to the third load 112 among the group of loads 110, and performs the check.

[0075] This allows the power supply control device 1 to check whether backup control by the second system 210 is executable, and to suppress a decrease in the state of charge of the second power supply 20 after the inspection. Therefore, the power supply control device 1 can quickly complete charging of the second power supply 20 after the inspection, and can quickly execute backup control after the inspection.

[0076] The power supply control device 1 includes an inter-system switch 41 and a battery switch 42. The inter-system switch 41 connects or disconnects the first system 200 and the second system 210. The battery switch 42 connects or disconnects the second power supply 20 and the second system 210. With the inter-system switch 41 disconnected and the battery switch 42 connected, the control unit 60 supplies power from the second power supply 20 to the third load 112 for a predetermined time, and performs an inspection based on the voltage of the LiB 21 after the predetermined time has elapsed.

[0077] As a result, the power supply control device 1 can disconnect the first system 200 and the second system 210, and perform an inspection by supplying power from the second power supply 20 to the third load 112 in the same state as when a ground fault occurs in the first system 200. Therefore, the power supply control device 1 can accurately determine whether or not backup control by the second power supply 20 can be performed.

[0078] When the control unit 60 executes the test, it turns off the first switch 43 corresponding to the second load 111.

[0079] This allows the power supply control device 1 to suppress a decrease in the state of charge of the second power supply 20 after the inspection. As a result, the power supply control device 1 can quickly complete charging of the second power supply 20 after the inspection, and can quickly execute backup control after the inspection.

[0080] (Second embodiment) Next, a power supply control device 300 according to a second embodiment will be described with reference to Fig. 8. Fig. 8 is a diagram showing an example of the configuration of a power supply control device 300 according to the second embodiment. Here, the description will focus on the differences from the first embodiment. The same components as those in the first embodiment will be assigned the same reference numerals as those in the first embodiment, and detailed description will be omitted.

[0081] The power supply control device 300 further includes a bypass switch 45 and a DC / DC converter (hereinafter referred to as "DC / DC 70").

[0082] The bypass switch 45 is provided in the second system 210. The bypass switch 45 is provided between the connection point between the inter-system line 220 and the second system 210 and the battery switch 42. The DC / DC 70 is connected in parallel with the bypass switch 45. The DC / DC 70 is controlled by the detection unit 61 and adjusts the voltage input to the LiB 21.

[0083] When the second power supply 20 is being charged, the switch setting unit 62 turns off the bypass switch 45, and the detection unit 61 drives the DC / DC 70. As a result, when the second power supply 20 is being charged, a current flows through the DC / DC 70. When the second power supply 20 is not being charged, the detection unit 61 stops the DC / DC 70.

[0084] When a ground fault occurs in the first system 200, the switch setting unit 62 turns on the bypass switch 45. When a test is performed to determine whether backup control by the second power source 20 can be performed, the switch setting unit 62 turns on the bypass switch 45. As a result, when power is supplied from the second power source 20, no current flows through the DC / DC converter 70, but only through the bypass switch 45.

[0085] When the detection unit 61 checks whether backup control by the second power source 20 can be performed, the detection unit 61 checks the operation of the bypass switch 45.

[0086] When the detection unit 61 checks whether backup control by the second power supply 20 is executable, it controls the DC / DC 70 so that a current smaller than the current flowing through the third load 112 when the bypass switch 45 is ON flows. Even when the DC / DC 70 is controlled so that a current smaller than the current flowing through the third load 112 flows, if the bypass switch 45 is ON, the current flows through the bypass switch 45. Therefore, if the bypass switch 45 is ON, the influence of the control of the DC / DC 70 is small. Therefore, the voltage of the LiB 21 drops due to the power supply to the third load 112 via the bypass switch 45.

[0087] In contrast, when the bypass switch 45 is fixed OFF, the influence of the control of the DC / DC 70 is large, and the voltage of the LiB 21 becomes higher than when the bypass switch 45 is ON.

[0088] When the detection unit 61 checks whether backup control by the second power source 20 can be performed, it can determine whether the bypass switch 45 is stuck OFF by detecting the voltage of the LiB 21 when the bypass switch 45 is turned ON.

[0089] Note that as a modified example of the method for determining whether the bypass switch 45 is stuck in OFF, the following may be used. That is, when checking whether backup control by the second power source 20 can be performed, the detection unit 61 stops the DC / DC converter 70 and turns ON the bypass switch 45. In a normal state in which the bypass switch 45 is not stuck in OFF, the voltage of the LiB 21 drops due to power supply to the third load 112 via the bypass switch 45. However, if the bypass switch 45 is stuck in OFF, no current flows to the third load 112, and the amount of voltage drop of the LiB 21 becomes zero. When checking whether backup control by the second power source 20 can be performed, the detection unit 61 determines that the bypass switch 45 is stuck in OFF if the amount of voltage drop of the LiB 21 is zero when the bypass switch 45 is ON.

[0090] The power supply control device 1 includes an inter-system switch 41, a DC / DC 70, and a bypass switch 45. The inter-system switch 41 connects or disconnects the first system 200 and the second system 210. The DC / DC 70 is provided in the second system 210. The bypass switch 45 is connected in parallel to the DC / DC 70. With the inter-system switch 41 disconnected and the bypass switch 45 connected, the control unit 60 supplies power from the second power supply 20 to the third load 112 for a predetermined time, and performs an inspection based on the voltage of the LiB 21 after the predetermined time has elapsed.

[0091] This allows the power supply control device 1 to check the operation of the bypass switch 45 while determining whether or not backup control by the second power supply 20 can be performed.

[0092] Further advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. [Explanation of symbols]

[0093] 1,300 Power supply control device 10 1st power supply 20 2nd power supply 41 Intersystem switch 42 Battery switch 43 Load switch, first switch 44 Load switch, second switch 45 Bypass Switch 60 Control Unit 61 Detector 62 Switch setting section 70 DC / DC converter 101 1st load 110 load group 111 2nd load 112 3rd load 120 Automatic driving control device

Claims

1. a first system capable of supplying power from a first power source to a first load; a second system capable of supplying power from a second power source to a load group including a second load and a third load consuming less power than the second load; a plurality of load switches each capable of switching power supply to each of the loads in the load group; a control unit that controls the load switch so that backup control by the second system is performed by power supply from the second power source when a ground fault is detected in the first system; Equipped with When checking whether the backup control is executable, the control unit connects a load switch corresponding to the third load among the group of loads and performs the check.

2. an inter-system switch that connects or disconnects the first system and the second system; a battery switch that connects or disconnects the second power supply and the second system; Equipped with 2. The power supply control device according to claim 1, wherein the control unit supplies power from the second power source to the third load for a predetermined time while the system switch is disconnected and the battery switch is connected, and performs the inspection based on a voltage of the second power source after the predetermined time has elapsed.

3. an inter-system switch that connects or disconnects the first system and the second system; a DC / DC converter provided in the second system; a bypass switch connected in parallel to the DC / DC converter; Equipped with 2. The power supply control device according to claim 1, wherein the control unit supplies power from the second power supply to the third load for a predetermined time with the inter-system switch disconnected and the bypass switch connected, and performs the inspection based on a voltage of the second power supply after the predetermined time has elapsed.

4. 4. The power supply control device according to claim 1, wherein the control unit turns off a load switch corresponding to the second load when the inspection is performed.

5. A control method for a power supply control device having a first system capable of supplying power from a first power source to a first load, a second system capable of supplying power from the second power source to a second load group including a second load and a third load that consumes less power than the second load, and a plurality of load switches capable of switching the power supply to each of the loads, when occurrence of a ground fault in the first system is detected, the load switch is controlled so that backup control by the second system is performed by power supply from the second power source; When it is checked whether the backup control is executable, a load switch corresponding to the third load among the second load group is connected, and the check is performed.

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