Power supply control device and power supply control method

Abstract

A power supply control device includes: a first system configured to supply power from a first power supply to a first load; a second system configured to supply power from a second power supply to a second load; an intersystem switch capable of connecting the first system to the second system and disconnecting the first system from the second system; a battery switch capable of connecting a second power supply to the second system and disconnecting the second power supply from the second system; a primary ground fault detection unit configured to disconnect the intersystem switch and connect the battery switch when the primary ground fault detection unit detects a ground fault in the first system or the second system; a secondary ground fault detection unit as defined herein; and a fault determination unit as defined herein.

Description

Technical Field

[0001] The disclosed embodiments relate to a power supply control device and a power supply control method. Background Art

[0002] A power supply control device includes: a first system that supplies power from a first power supply to a first load; a second system that supplies power from a second power supply to a second load; an inter-system switch that can connect the first system to the second system and disconnect the first system from the second system; and a battery switch that can connect the second power supply to the second system and disconnect the second power supply from the second system.

[0003] When the power supply control device detects that the voltage of the first or second system has dropped below a ground fault determination threshold, the power supply control device disconnects the intersystem switch and specifies the system in which the ground fault has occurred. When the voltage of the first and second systems returns to a value equal to or greater than the ground fault value within a predetermined time, the power supply control device determines that the first and second systems are normal, reconnects the intersystem switch, and resumes normal control (for example, see JP-A-2019-62727). Summary of the Invention

[0004] However, in a power supply control device, when the inter-system switch is in a fixed open state, the second power supply cannot be charged, and thus the state of charge (SOC) of the second power supply is insufficient, and there is a possibility that the desired backup cannot be performed. Therefore, the power supply control device needs to detect the fixed open state of the inter-system switch.

[0005] One aspect of the embodiments has been made in view of the above circumstances, and an object thereof is to provide a power supply control device and a power supply control method capable of detecting a fixed open state of an inter-system switch.

[0006] A power supply control device according to one aspect of an embodiment includes a first system, a second system, an intersystem switch, a battery switch, a primary ground fault detection unit, a secondary ground fault detection unit, and a fault determination unit. The first system supplies power from a first power source to a first load. The second system supplies power from a second power source to a second load. The intersystem switch can connect the first system to the second system and disconnect the first system from the second system. The battery switch can connect the second power source to the second system and disconnect the second power source from the second system. When a ground fault is detected in either the first or second system, the primary ground fault detection unit disconnects the intersystem switch and connects the battery switch. When the primary ground fault detection unit detects a ground fault, the secondary ground fault detection unit specifies whether the system in which the ground fault was detected is the first or second system. When the ground fault is resolved, the secondary ground fault detection unit performs recovery control to reconnect the intersystem switch and disconnect the battery switch. The fault determination unit determines that the intersystem switch is in a fixed open state when the frequency of the recovery control and ground fault detection performed by the primary ground fault detection unit after the primary ground fault detection unit detects the ground fault is equal to or greater than a predetermined frequency.

[0007] A power supply control method according to an aspect of the embodiment includes: a primary ground fault detection step performed by a primary ground fault detection unit of a power supply control device, the power supply control device including: a first system configured to supply power of a first power supply to a first load; a second system configured to supply power of a second power supply to a second load; an inter-system switch capable of connecting the first system to the second system and disconnecting the first system from the second system; and a battery switch capable of connecting the second power supply to the second system and disconnecting the second power supply from the second system, wherein when the primary ground fault detection unit detects a ground fault in the first system or the second system, the inter-system switch is disconnected, and turning on the battery switch; a secondary ground fault detection step, performed by the secondary ground fault detection unit of the power supply control device, specifying whether the system in which the ground fault is detected is the first system or the second system when the primary ground fault detection unit detects the ground fault, and performing recovery control of reconnecting the inter-system switch and disconnecting the battery switch when the ground fault is eliminated; and a fault determination step, performed by the fault determination unit of the power supply control device, determining that the inter-system switch is in a fixed open state when a frequency at which the recovery control and the detection of the ground fault by the primary ground fault detection unit are repeated after the primary ground fault detection unit detects the ground fault is equal to or higher than a predetermined frequency.

[0008] The power supply control device and the power supply control method according to one aspect of the embodiment have an effect of being able to detect a fixed open state of an inter-system switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is an explanatory diagram showing a configuration example of a power supply control device according to an embodiment.

[0010] Figure 2 is an explanatory diagram showing an operation example of the power supply control device according to the embodiment.

[0011] Figure 3 is an explanatory diagram showing an operation example of the power supply control device according to the embodiment.

[0012] Figure 4 is an explanatory diagram showing an operation example of the power supply control device according to the embodiment.

[0013] Figure 5 is an explanatory diagram showing an operation example of the power supply control device according to the embodiment.

[0014] Figure 6 is an explanatory diagram showing an operation example of the power supply control device according to the embodiment.

[0015] Figure 7 is an explanatory diagram showing an operation example of the power supply control device according to the embodiment.

[0016] Figure 8 is an explanatory diagram showing an operation example of the power supply control device according to the embodiment.

[0017] Figure 9 is an explanatory diagram showing a configuration example of a switch drive unit according to the embodiment.

[0018] Figure 10 is a flowchart illustrating an example of a process performed by a switch driving unit according to the embodiment. DETAILED DESCRIPTION

[0019] Hereinafter, embodiments of a power supply control device will be described in detail with reference to the accompanying drawings. The present invention is not limited to the following embodiments. Hereinafter, a power supply control device installed in a vehicle with an autonomous driving function and supplying power to a load will be described as an example. However, the power supply control device according to the embodiments can also be installed in vehicles without autonomous driving functions.

[0020] Furthermore, although a case will be described where the vehicle on which the power supply control device is mounted is an electric vehicle or a hybrid vehicle, the vehicle on which the power supply control device is mounted may be an engine vehicle that travels by an internal combustion engine.

[0021] The power control device according to the embodiment includes a first power supply and a second power supply. When a power failure occurs in one of the first power supply or the second power supply in the power supply system, the power control device can be installed in any device in which the first power supply is backed up by another power supply system.

[0022] [1. Configuration of power supply control device]

[0023] Figure 1 1 is an explanatory diagram showing a configuration example of a power supply control device according to an embodiment. Figure 1 As shown, the power supply control device 1 according to the embodiment is connected to a first power supply 10, a first load 101, a general load 102, a second load 103, and an automatic driving control device 100. The power supply control device 1 includes: a first system 110 that supplies power from the first power supply 10 to the first load 101 and the general load 102; and a second system 120 that supplies power from a second power supply 20, which will be described below, to the second load 103.

[0024] The first load 101 includes loads used for autonomous driving. For example, the first load 101 includes a steering motor, an electronic brake device, an onboard camera, etc. The general load 102 includes, for example, a display, air conditioning, audio, video, and various lights.

[0025] Second load 103 includes a portion of the autonomous driving function of first load 101. For example, second load 103 includes the minimum necessary equipment for fail-safe operation (FOP), such as a steering motor, an electronic brake device, and a radar. First load 101, general load 102, and second load 103 are operated by power supplied from power supply control device 1.

[0026] The autonomous driving control device 100 is a device that performs autonomous driving control of a vehicle. The autonomous driving control device 100 causes the vehicle to travel autonomously by operating a first load 101 and a second load 103. Furthermore, during autonomous driving, the autonomous driving control device 100 can perform FOP via the second load 103 if a ground fault occurs in the first system 110, and can also perform FOP via the first load 101 if a ground fault occurs in the second system 120.

[0027] 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 the PbB 12.

[0028] The DC / DC converter 11 is connected to a generator and a high-voltage battery having a voltage higher than that of the PbB 12, steps down the voltage of the generator and the high-voltage battery, and outputs the stepped-down voltage to the first system 110. The generator is, for example, an AC generator that converts the kinetic energy of a moving vehicle into electricity to generate power. The high-voltage battery is, for example, a battery installed in an electric vehicle or hybrid vehicle to drive the vehicle.

[0029] When the first power supply 10 is installed in a motor vehicle, an AC generator (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 second load 103, and charges the second power supply 20, which will be described below.

[0030] The power supply control device 1 includes a second power supply 20, an inter-system switch 41, a battery switch 42, a switch drive unit 3, a first voltage sensor 51, and a second voltage sensor 52. The second power supply 20 is a backup power supply for situations where the first power supply 10 cannot supply power. The second power supply 20 includes a lithium-ion battery (hereinafter referred to as "LiB 21"). The battery of the second power supply 20 can be any secondary battery other than the LiB 21.

[0031] The intersystem switch 41 is provided in the intersystem line 130 that connects the first system 110 to the second system 120, and is capable of connecting the first system 110 to the second system 120 and disconnecting the first system 110 from the second system 120. The battery switch 42 is a switch that connects the second power source 20 to the second system 120. In the following description, connecting the intersystem switch 41 means electrically connecting the first system 110 to the second system 120, that is, conducting electricity between the first system 110 and the second system 120. In addition, disconnecting the intersystem switch 41 means disconnecting (that is, severing) the electrical connection between the first system 110 and the second system 120.

[0032] The first voltage sensor 51 is provided in the first system 110, detects the voltage of the first system 110, and outputs the detection result to the switch driving unit 3. The second voltage sensor 52 is provided in the second system 120, detects the voltage of the second system 120, and outputs the detection result to the switch driving unit 3.

[0033] The switch driving unit 3 includes a microcomputer having a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), etc., and various circuits. The switch driving unit 3 can be composed of hardware such as an application-specific integrated circuit (ASIC) or a field programmable gate array (FPGA).

[0034] Switch driving unit 3 includes a primary ground fault detection unit 31, a secondary ground fault detection unit 32, and a fault determination unit 33, which are operated by the CPU using RAM as a work area to execute a program stored in ROM, and controls the operation of power supply control device 1. As described above, primary ground fault detection unit 31 can be operated by the CPU of a microcomputer. However, as an example of another embodiment, primary ground fault detection unit 31 can also be configured as a hardware circuit including a comparator for detecting a voltage drop and a one-shot multivibrator for outputting a one-shot pulse signal of, for example, 50 ms.

[0035] The primary ground fault detection unit 31 detects a ground fault in the first system 110 or the second system 120 using hardware (e.g., a comparator and a one-shot multivibrator). Therefore, the primary ground fault detection unit 31 can quickly detect a ground fault. When the primary ground fault detection unit 31 detects a ground fault in the first system 110 or the second system 120, the primary ground fault detection unit 31 turns off the inter-system switch 41 and turns on the battery switch 42.

[0036] Secondary ground fault detection unit 32 detects a ground fault in first system 110 or second system 120 using software. Therefore, due to the influence of AD conversion of the output voltages of first voltage sensor 51 and second voltage sensor 52, etc., secondary ground fault detection unit 32 detects a ground fault more slowly than primary ground fault detection unit 31. When primary ground fault detection unit 31 detects a ground fault, secondary ground fault detection unit 32 specifies whether the system in which the ground fault was detected is first system 110 or second system 120. When the ground fault is eliminated, secondary ground fault detection unit 32 performs recovery control to reconnect intersystem switch 41 and disconnect battery switch 42.

[0037] The fault determination unit 33 determines whether the inter-system switch 41 is in a fixed open state. Figure 9 A specific configuration example of the switch drive unit 3 will be described. When the power supply control apparatus 1 is activated, the switch drive unit 3 connects (turns on) the inter-system switch 41 and disconnects (turns off) the battery switch 42 .

[0038] Switch driving unit 3 detects a ground fault of first system 110 or second system 120 based on the detection results input from first and second voltage sensors 51 and 52. A specific example of a method for detecting a ground fault by switch driving unit 3 will be described below.

[0039] When a ground fault is detected in the first system 110 or the second system 120, the switch drive unit 3 notifies the automatic driving control device 100 of this fact. When a ground fault is detected in the first system 110 or the second system 120, the switch drive unit 3 outputs an automatic driving prohibition signal indicating that automatic driving is not possible to the automatic driving control device 100. When a ground fault is not detected in the first system 110 or the second system 120, the switch drive unit 3 outputs an automatic driving permission signal indicating that automatic driving is possible to the automatic driving control device 100.

[0040] When a power failure such as a ground fault occurs in the first system 110, the switch drive unit 3 disconnects the intersystem switch 41, connects the battery switch 42, and supplies power from the second power source 20 to the second load 103. When a power failure such as a ground fault occurs in the second system 120, the switch drive unit 3 supplies power from the first power source 10 to the first load 101 and the general load 102 while disconnecting the intersystem switch 41 and disconnecting the battery switch 42.

[0041] Therefore, during automatic driving, even if one of the multiple systems has a ground fault, the power supply control device 1 can use another system to execute FOP for making the vehicle perform retreat driving to a safe place through the automatic driving control device 100 and stop the vehicle. Figures 2 to 8 The operation of the power supply control device 1 will be described.

[0042] [2. Normal operation of the power control device]

[0043] In normal operation when no ground fault occurs in the first system 110 and the second system 120, as shown in FIG. Figure 2 As shown, the switch drive unit 3 disconnects the battery switch 42, connects the inter-system switch 41, and supplies power from the first power source 10 to the first load 101, the general load 102, and the second load 103. In normal operation without a ground fault as described above, the switch drive unit 3 outputs an automatic driving permission signal to the automatic driving control device 100.

[0044] [3. Operation of the power supply control device when a ground fault occurs]

[0045] Next, we will refer to Figures 3 to 5 The operation of the power supply control device 1 when a ground fault occurs is described below. Figure 3 As shown, in the power supply control device 1, for example, when a ground fault 200 occurs in the first system 110 or a ground fault 201 occurs in the second system 120, an overcurrent flows to the ground fault point, and therefore, the voltages detected by the first voltage sensor 51 and the second voltage sensor 52 become equal to or less than the ground fault determination threshold value.

[0046] Therefore, for example, when the voltage detected by the second voltage sensor 52 becomes equal to or less than the ground fault determination threshold, the switch drive unit 3 temporarily determines that a ground fault 200 or 201 has occurred in the first system 110 or the second system 120, and outputs an automatic driving prohibition signal to the automatic driving control device 100. When the switch drive unit 3 temporarily determines that a ground fault 200 or 201 has occurred, the switch drive unit 3 disconnects the inter-system switch 41 and connects the battery switch 42. As a result, the first system 110 and the second system 120 are disconnected, power is supplied from the first power supply 10 to the first system 110, and power is supplied from the second power supply 20 to the second system 120.

[0047] The switch driving unit 3 may also temporarily determine that a ground fault occurs in the first system 110 or the second system 120 when the voltage detected by at least one of the first voltage sensor 51 and the second voltage sensor 52 becomes equal to or less than the ground fault determination threshold.

[0048] Thereafter, when the voltage detected by the first voltage sensor 51 is equal to or less than the ground fault determination threshold value for a predetermined time or longer, and the voltage detected by the second voltage sensor 52 recovers to a value exceeding the ground fault determination threshold value for a predetermined time, the switch driving unit 3 determines that a ground fault 200 has occurred in the first system 110.

[0049] In this case, if Figure 4 As shown, the switch drive unit 3 supplies power from the second power source 20 to the second load 103 and notifies the autonomous driving control device 100 of this fact. Therefore, the autonomous driving control device 100 can operate the second load 103 using the power supplied from the second power source 20 to cause the vehicle to perform a retreat trip to a safe location and stop the vehicle. The autonomous driving control device 100 can be configured to start the retreat trip when the autonomous driving prohibition signal is input from the power supply control device 1.

[0050] Furthermore, after temporarily determining that a ground fault has occurred in the first system 110 or the second system 120, when the voltage detected by the second voltage sensor 52 is equal to or less than the ground fault determination threshold value even after the predetermined time has elapsed, and the voltage detected by the first voltage sensor 51 recovers to a value exceeding the ground fault determination threshold value within the predetermined time, the switch driving unit 3 determines that a ground fault 201 has occurred in the second system 120.

[0051] In this case, if Figure 5As shown, the switch drive unit 3 disconnects the battery switch 42, supplies power from the first power source 10 to the first load 101, and notifies the autonomous driving control device 100 of this fact. Thus, the autonomous driving control device 100 can operate the first load 101 using the power supplied from the first power source 10, causing the vehicle to perform a retreat operation to a safe location and stop the vehicle. The autonomous driving control device 100 can be configured to initiate the retreat operation when the autonomous driving prohibition signal is input from the power supply control device 1.

[0052] The switch driving unit 3 is connected to the second power source 20 and monitors the voltage of the second power source 20 (the state of charge (SOC) of the LiB 21). Figure 6 As shown, when the voltage of the second power source 20 drops to a predetermined voltage or lower, the switch driving unit 3 turns on the inter-system switch 41 and the battery switch 42 to charge the second power source 20 through the DC / DC 11 .

[0053] [4. Issue of fixed open circuit state of inter-system switches]

[0054] In power supply control device 1, when first load 101 or general load 102 temporarily becomes an overload state instead of ground fault 200 or 201, the voltage detected by first voltage sensor 51 may temporarily become equal to or less than the ground fault determination threshold value. In power supply control device 1, when second load 103 temporarily becomes an overload state, the voltage detected by second voltage sensor 52 may temporarily become equal to or less than the ground fault determination threshold value.

[0055] In this case, in the power supply control device 1, power is continuously supplied from the first power supply 10 to the first load 101 and the general load 102, and power is continuously supplied from the second power supply 20 to the second load 103. Therefore, after temporarily determining that the ground fault 200 or 201 has occurred in the first system 110 or the second system 120, before a predetermined time has passed, if the voltages detected by both the first voltage sensor 51 and the second voltage sensor 52 are restored to a value exceeding the ground fault determination threshold, the switch drive unit 3 determines that there is no abnormality in the power supply due to the transient voltage drop. Thereafter, in order to restore the power supply control device 1 to Figure 2 In the normal operation shown, the switch driving unit 3 disconnects the battery switch 42 and connects the inter-system switch 41 again.

[0056] At this time, if Figure 7 As shown, when the intersystem switch 41 is in a fixed open state, even if an attempt is made to disconnect the battery switch 42 and then connect the intersystem switch 41 again, the battery switch 42 may be disconnected, but the intersystem switch 41 may not be turned on. Therefore, since power is not supplied from the first power source 10 to the second system 120, the voltage drops to the ground fault determination threshold.

[0057] As a result, the switch driving unit 3 temporarily determines that a ground fault 201 occurs in the second system 120, and Figure 8 As shown, the switch driving unit 3 disconnects the inter-system switch 41 and reconnects the battery switch 42. Therefore, power is supplied from the second power supply 20 to the second system 120, and the voltage of the second system 120 recovers to a value exceeding the ground fault determination threshold.

[0058] Therefore, the switch drive unit 3 determines that the power supply has no abnormality due to the transient voltage drop, and in order to restore the power supply control device 1 to normal operation, attempts to disconnect the battery switch 42 and connect the inter-system switch 41 again, but the state of the power supply control device 1 returns to Figure 7 As described above, when the inter-system switch 41 is in a fixed open state, the power supply control device 1 alternately repeats Figure 7 The status shown and Figure 8 That is, the power supply control device 1 repeats the disconnection and reconnection of the battery switch 42.

[0059] At this time, the power supply control device 1 consumes the power of the second power supply 20 while the battery switch 42 is turned on, but because the inter-system switch 41 is in a fixed open state, the inter-system switch 41 and the battery switch 42 are not turned on, and the second power supply 20 cannot be charged. Therefore, the switch drive unit 3 of the power supply control device 1 according to the embodiment includes a fault determination unit 33 that detects the fixed open state of the inter-system switch 41.

[0060] [5. Configuration Example of Switch Driving Unit According to the Embodiment]

[0061] Next, we will refer to Figure 9 A configuration example of the switch drive unit 3 according to the embodiment is described. Figure 9 : is an explanatory diagram showing a configuration example of the switch drive unit 3 according to the embodiment.

[0062] like Figure 9 As shown, the switch driving unit 3 includes a primary ground fault detection unit 31, a secondary ground fault detection unit 32, a fault determination unit 33, an OR logic circuit 34, and an OR logic circuit 35. The detection result of the voltage of the first system 110 is input from the first voltage sensor 51, and the detection result of the voltage of the second system 120 is input from the second voltage sensor 52 to the primary ground fault detection unit 31 and the secondary ground fault detection unit 32.

[0063] When primary ground fault detection unit 31 detects a ground fault in first system 110 or second system 120, it switches off intersystem switch 41 and switches on battery switch 42. Specifically, when the voltage of first system 110 or second system 120 becomes equal to or less than a ground fault determination threshold, primary ground fault detection unit 31 outputs a primary ground fault detection signal to secondary ground fault detection unit 32, OR logic circuit 34, and OR logic circuit 35. In this case, primary ground fault detection unit 31 outputs a primary ground fault detection signal of a single pulse, for example, 50 ms. Upon receiving the primary ground fault detection signal from primary ground fault detection unit 31, secondary ground fault detection unit 32 outputs the secondary ground fault detection signal to OR logic circuit 34, OR logic circuit 35, and fault determination unit 33.

[0064] When a primary ground fault detection signal or a secondary ground fault detection signal is input from the primary ground fault detection unit 3, the OR logic circuit 35 outputs a disconnection signal to the intersystem switch 41 to disconnect the intersystem switch 41. When a primary ground fault detection signal is input from the primary ground fault detection unit 31 or a secondary ground fault detection signal is input from the secondary ground fault detection unit 32, the OR logic circuit 34 outputs a control signal to the battery switch 42 to connect the battery switch 42.

[0065] That is, because the detection speed of the primary ground fault detection unit 31 is higher than the detection speed of the secondary ground fault detection unit 32, when the voltage of the first system 110 or the second system 120 decreases, the inter-system switch 41 is immediately turned off and the battery switch 42 is turned on by the primary ground fault detection signal from the primary ground fault detection unit 31. Thereafter, the secondary ground fault detection signal from the secondary ground fault detection unit 32 causes the inter-system switch 41 to be turned off and the battery switch 42 to be turned on continuously.

[0066] When the primary ground fault detection unit 31 detects a ground fault, the secondary ground fault detection unit 32 specifies whether the system in which the ground fault is detected is the first system 110 or the second system 120, and when the ground fault is eliminated, the secondary ground fault detection unit performs recovery control of reconnecting the inter-system switch 41 and disconnecting the battery switch 42.

[0067] Specifically, when the primary ground fault detection unit 31 detects a ground fault, the secondary ground fault detection unit 32 samples the voltages of the first system 110 and the second system 120 at a predetermined cycle for a predetermined period of time. Then, the secondary ground fault detection unit 32 designates a system in which a voltage equal to or less than a ground fault determination threshold is continuously sampled for a predetermined time (e.g., 100 milliseconds) or longer as a system in which a ground fault is detected.

[0068] Furthermore, when the secondary ground fault detection unit 32 continuously samples a voltage exceeding the ground fault determination threshold for a predetermined time (e.g., 40 ms) or longer, the secondary ground fault detection unit 32 determines that the ground fault is not persisting and stops outputting the secondary ground fault detection signal to the OR logic circuit 35. In other words, it outputs a connection signal. When the connection signal is input from the secondary ground fault detection unit 32, the OR logic circuit 35 outputs the connection signal to the intersystem switch 41 to reconnect the intersystem switch 41. At this point, the secondary ground fault detection unit 32 outputs a control signal to the battery switch 42 via the OR logic circuit 34 to disconnect the battery switch 42.

[0069] When the frequency at which restoration control and ground fault detection by the primary ground fault detection unit 31 are repeated after the primary ground fault detection unit 31 detects a ground fault is equal to or higher than a predetermined frequency, the fault determination unit 33 determines that the inter-system switch 41 is in a fixed open state.

[0070] Specifically, the fault determination unit 33 includes a fixed open circuit determination timer 36 and a disconnection number counter 37. The fixed open circuit determination timer 36 resets the measurement time every time a predetermined time passes. For example, the fixed open circuit determination timer 36 resets the measurement time every 5 seconds.

[0071] Each time a signal indicating that a ground fault has occurred in the first system 110 or the second system 120 is input from the primary ground fault detection unit 31 via the secondary ground fault detection unit 32, the disconnection number counter 37 increments the count value indicating the disconnection number of the inter-system switch 41 by 1. The disconnection number counter 37 resets the count value each time the measurement time of the fixed open circuit determination timer 36 becomes equal to or longer than a predetermined time.

[0072] When the count value of the cutoff times counter 37 reaches a predetermined number of times (for example, 3 times) or more before the measurement time of the fixed open circuit determination timer 36 reaches a predetermined time, the fault determination unit 33 determines that the fault has occurred. Figure 7 The status shown and Figure 8 The state shown is repeated at a predetermined frequency or higher, and it is determined that the intersystem switch 41 is in a fixed open state. As described above, according to the power supply control device 1, the fault determination unit 33 can determine whether the intersystem switch 41 is in a fixed open state.

[0073] If fault determination unit 33 determines that inter-system switch 41 is in a fixed open state, fault determination unit 33 outputs an automatic driving prohibition signal to automatic driving control device 100 to prohibit automatic driving. Therefore, in power supply control device 1, inter-system switch 41 is in a fixed open state, and switching to automatic driving in a dangerous state where second power supply 20 cannot back up first power supply 10 can be prevented.

[0074] After determining that the inter-system switch 41 is in the fixed open state, the fault determination unit 33 prohibits the primary ground fault detection unit 31 from turning on the battery switch 42 even when the primary ground fault detection unit detects a ground fault.

[0075] Specifically, after determining that the inter-system switch 41 is in a fixed open state, when a signal indicating that a ground fault has been detected in the first system 110 or the second system 120 is input from the primary ground fault detection unit 31 via the secondary ground fault detection unit 32, the fault determination unit 33 outputs a control signal to the battery switch 42 that prohibits subsequent conduction of the battery switch 42.

[0076] Therefore, the power supply control device 1 can suppress the degradation of the LiB 21 due to repeated discharge by preventing the second power supply 20 from being discharged unnecessarily after the inter-system switch 41 is in the fixed open state.

[0077] [6. Processing performed by the switch driving unit]

[0078] Next, we will refer to Figure 10 The processing performed by the switch drive unit 3 of the power supply control device 1 is described. Figure 10 is a flowchart showing an example of processing performed by the switch drive unit 3 of the power supply control device 1 according to the embodiment. The switch drive unit 3 repeatedly performs Figure 10 The processing shown.

[0079] Specifically, if Figure 10 As shown, the switch driving unit 3 first determines whether the fixed open circuit determination time of the inter-system switch 41 is equal to or longer than a predetermined time (step S101). When it is determined that the fixed open circuit determination time is not equal to or longer than the predetermined time (step S101: No), the switch driving unit 3 moves the process to step S103.

[0080] When it is determined that the fixed open circuit determination time is equal to or longer than the predetermined time (step S101: Yes), the switch drive unit 3 resets the fixed open circuit determination timer 36 and the disconnection number counter 37 (step S102), and determines whether a power supply abnormality has occurred (step S103). When the switch drive unit 3 determines that no power supply abnormality has occurred (step S103: No), the process proceeds to step S101.

[0081] When determining that a power abnormality has occurred (step S103: YES), the switch driving unit 3 turns off the inter-system switch 41 and turns on the battery switch 42 (step S104). Subsequently, the switch driving unit 3 increases the count value of the disconnection number counter 37 by 1 (step S105).

[0082] Then, the switch driving unit 3 determines whether the number of times the inter-system switch 41 has been turned off is equal to or greater than a predetermined number (step S106). When it is determined that the number of times the inter-system switch 41 has been turned off is equal to or greater than the predetermined number (step S106: Yes), the switch driving unit 3 turns off the inter-system switch 41 and the battery switch 42 (step S107), prohibits automatic operation, prohibits the battery switch 42 from being turned on (step S108), and ends the process.

[0083] When determining that the number of cutoff times is not equal to or greater than the predetermined number of times (step S106 : No), the switch driving unit 3 determines whether power supply abnormality is confirmed (step S109 ).

[0084] When it is determined that the power abnormality has not been confirmed (step S109: No), the switch drive unit 3 turns on the inter-system switch 41 and the battery switch 42 (step S110), and the process proceeds to step S101. When it is determined that the power abnormality has been confirmed (step S109: Yes), the switch drive unit 3 performs fail-safe control (step S111), and ends the process.

[0085] Those skilled in the art will readily derive additional effects and modifications. Therefore, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Therefore, 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.

[0086] Reference Signs List

[0087] 1 Power control device

[0088] 10 First Power Source

[0089] 11 DC / DC

[0090] 12 PbB

[0091] 20 Second power supply

[0092] 21 LiB

[0093] 3 Switch drive unit

[0094] 31 Primary ground fault detection unit

[0095] 32 Secondary ground fault detection unit

[0096] 33 Fault determination unit

[0097] 34 OR logic circuit

[0098] 35 OR logic circuit

[0099] 36 Fixed open circuit confirmation timer

[0100] 37 Cut-off counter

[0101] 41 Inter-system switch

[0102] 42 Battery switch

[0103] 51 First voltage sensor

[0104] 52 Second voltage sensor

[0105] 100 autonomous driving control equipment

[0106] 101 First Load

[0107] 102 General load

[0108] 103 Second load

[0109] 110 First System

[0110] 120 Second system.

Claims

1. A power control device, comprising: a first system configured to supply power from a first power source to a first load; a second system configured to supply power from a second power source to a second load; an intersystem switch capable of connecting the first system to the second system and disconnecting the first system from the second system; a battery switch capable of connecting the second power source to the second system and disconnecting the second power source from the second system; a primary ground fault detection hardware circuit, configured to disconnect the inter-system switch and connect the battery switch when the primary ground fault detection hardware circuit detects a ground fault in the first system or the second system; a secondary ground fault detection unit configured to detect a ground fault in the first system or the second system by software when the primary ground fault detection hardware circuit detects a ground fault, the secondary ground fault detection unit detecting a ground fault at a slower speed than the primary ground fault detection hardware circuit, the secondary ground fault detection unit specifying whether the system in which the ground fault is detected is the first system or the second system, and, when the ground fault is eliminated, executing recovery control to reconnect the inter-system switch and disconnect the battery switch; as well as a fault determination unit configured to determine that the inter-system switch is in a fixed open state when, after the primary ground fault detection hardware circuit detects the ground fault, a frequency at which the restoration control and the detection of the ground fault by the primary ground fault detection hardware circuit are repeated is equal to or higher than a predetermined frequency.

2. The power supply control device according to claim 1, in, The fault determination unit is configured to inhibit the automatic driving control device from automatically driving when the fault determination unit determines that the inter-system switch is in the fixed open state.

3. The power supply control device according to claim 1 or 2, in, The fault determination unit is configured to prohibit the primary ground fault detection hardware circuit from turning on the battery switch even when the primary ground fault detection hardware circuit detects a ground fault after the fault determination unit determines that the inter-system switch is in the fixed open state.

4. A power control method, comprising: A primary ground fault detection step is performed by a primary ground fault detection hardware circuit of a power supply control device, the power supply control device comprising: a first system configured to supply power from a first power source to a first load; a second system configured to supply power from a second power source to a second load; an intersystem switch capable of connecting the first system to the second system and disconnecting the first system from the second system; and a battery switch capable of connecting the second power source to the second system and disconnecting the second power source from the second system, the primary ground fault detection step comprising disconnecting the intersystem switch and connecting the battery switch when the primary ground fault detection hardware circuit detects a ground fault in the first system or the second system. a secondary ground fault detection step, performed by a secondary ground fault detection unit of the power supply control device, the secondary ground fault detection step comprising: when the primary ground fault detection hardware circuit detects a ground fault, the secondary ground fault detection unit detecting a ground fault in the first system or the second system by software, the secondary ground fault detection unit detecting a ground fault at a slower speed than the primary ground fault detection hardware circuit, the secondary ground fault detection unit specifying whether the system in which the ground fault was detected is the first system or the second system, and when the ground fault is eliminated, executing recovery control to reconnect the inter-system switch and disconnect the battery switch; and and a fault determination step, performed by a fault determination unit of the power supply control device, comprising determining that the inter-system switch is in a fixed open state when, after the primary ground fault detection hardware circuit detects the ground fault, a frequency at which the recovery control and the detection of the ground fault by the primary ground fault detection hardware circuit are repeated is equal to or higher than a predetermined frequency.

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