Power control device

Abstract

To provide a power supply control unit that, when ground fault really occurs, can prevent a delay in fail-safe control.SOLUTION: A power supply control unit 1 comprises: a first system 110 that supplies power of a first power supply 10 to a first load 101; a second system 120 that supplies power of a second power supply 20 to a second load 103; an inter-system switch 41 that can connect the first system and the second system to each other and cut off the systems from each other; a first detection unit 31 that detects an abnormality in the first system or the second system based on a physical quantity indicating the state of the first system or the second system and a first threshold; and a second detection unit 32 that identifies whether the system in which the abnormality is detected by the first detection unit is the first system or the second system with a longer time than the time of detection performed by the first detection unit based on the physical quantity and a second threshold that is set to increase the sensitivity to detect an abnormality compared with the first threshold, and makes a transition to fail-safe control.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The disclosed embodiments relate to a power control device.

Background Art

[0002] There is a power control device including a first system that supplies power of a first power source to a first load, a second system that supplies power of a second power source to a second load, and an inter-system switch capable of connecting and disconnecting the first system and the second system.

[0003] When the power control device detects a ground fault in the first system or the second system by hardware, it shuts off the inter-system switch, and then identifies whether the system in which the ground fault has been detected is the first system or the second system by software and shifts to fail-safe control (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, since the determination time for detecting a ground fault by software is longer than that for detecting a ground fault by hardware, when a true ground fault has occurred, the fail-safe control is delayed.

[0006] One aspect of the embodiment is made in view of the above, and an object thereof is to provide a power control device capable of preventing the fail-safe control from being delayed when a true ground fault has occurred.

Means for Solving the Problems

[0007] A power control device according to an aspect of the embodiment includes a first system, a second system, an inter-system switch, a first detection unit, and a second detection unit. The first system supplies the power of the first power source to the first load. The second system supplies the power of the second power source to the second load. The inter-system switch can connect and disconnect the first system and the second system. The first detection unit detects an abnormality in the first system or the second system based on a physical quantity indicating the state of the first system or the second system and a first threshold value. The second detection unit identifies, based on the physical quantity and a second threshold value set to have a higher sensitivity for detecting an abnormality than the first threshold value, whether the system in which an abnormality is detected by the first detection unit is the first system or the second system, over a time longer than the detection time by the first detection unit, and shifts to fail-safe control.

Advantages of the Invention

[0008] The power control device according to an aspect of the embodiment has an effect of preventing a delay in fail-safe control when a true ground fault has occurred.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiment for Carrying Out the Invention

[0010] Hereinafter, embodiments of the power control device and the power control method will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited by the embodiments shown below. In the following, a power control device mounted on a vehicle having an automatic driving function and supplying power to a load will be described as an example, but the power control device according to the embodiment may be mounted on a vehicle not having an automatic driving function.

[0011] Also, in the following, the case where the vehicle on which the power control device is mounted is an electric vehicle or a hybrid vehicle will be described, but the vehicle on which the power control device is mounted may be an engine vehicle that runs by an internal combustion engine.

[0012] Note that the power control device according to the embodiment includes a first power source and a second power source, and when a power failure occurs in either one of the power source systems of the first power source and the second power source, the first power source is backed up by the other power source system, and it may be mounted on any device.

[0013] [1. Configuration of Power Control Device] FIG. 1 is an explanatory diagram showing a configuration example of the power control device according to the embodiment. As shown in FIG. 1, the power control device 1 according to the embodiment is connected to a first power source 10, a first load 101, a general load 102, a second load 103, and an automatic driving control device 100. The power control device 1 includes a first system 110 that supplies the power of the first power source 10 to the first load 101 and the general load 102, and a second system 120 that supplies the power of a second power source 20, which will be described later, to the second load 103.

[0014] The first load 101 includes loads for autonomous driving. For example, the first load 101 includes a steering motor, an electric brake device, an in-vehicle camera, etc. that operate during autonomous driving. The general load 102 includes, for example, a display, an air conditioner, an audio system, a video system, and various lights, etc.

[0015] The second load 103 includes a part of the functions for autonomous driving that the first load 101 has. For example, the second load 103 includes devices that are minimally necessary for FOP (fail-safe control) of a steering motor, an electric brake device, a radar, etc. The first load 101, the general load 102, and the second load 103 operate by the electric power supplied from the power control device 1.

[0016] The autonomous driving control device 100 is a device that controls the vehicle for autonomous driving. The autonomous driving control device 100 makes the vehicle travel by autonomous driving by operating the first load 101 and the second load 103. Also, when a ground fault occurs in the first system 110 during autonomous driving, the autonomous driving control device 100 can perform FOP by the second load 103, and when a ground fault occurs in the second system 120, the autonomous driving control device 100 can perform FOP by the first load 101.

[0017] The first power supply 10 includes a DC / DC converter (hereinafter referred to as "DC / DC11") and a lead battery (hereinafter referred to as "PbB12"). Note that the battery of the first power supply 10 may be any secondary battery other than PbB12.

[0018] DC / DC11 is connected to a generator and a high-voltage battery having a voltage higher than that of PbB12, steps down the voltages of the generator and the high-voltage battery, and outputs them to the first system 110. The generator is, for example, an alternator that generates electricity by converting the kinetic energy of a traveling vehicle into electricity. The high-voltage battery is, for example, a vehicle drive battery mounted on an electric vehicle or a hybrid vehicle.

[0019] Note that when the first power supply 10 is mounted on an engine vehicle, an alternator (generator) is provided instead of the DC / DC 11. The DC / DC 11 performs charging of the PbB 12, power supply to the first load 101 and the general load 102, power supply to the second load 103, and charging of the second power supply 20 described later.

[0020] The power supply control device 1 includes a second power supply 20, an inter-system switch 41, a battery switch 42, a switch driving unit 3, a first voltage sensor 51, and a second voltage sensor 52. The second power supply 20 is a backup power supply when the power supply by the first power supply 10 becomes unavailable. The second power supply 20 includes a lithium-ion battery (hereinafter referred to as "LiB 21"). Note that the battery of the second power supply 20 may be any secondary battery other than the LiB 21.

[0021] The inter-system switch 41 is provided on an inter-system line 130 that connects the first system 110 and the second system 120, and is a switch capable of connecting and disconnecting the first system 110 and the second system 120. The battery switch 42 is a switch that connects the second power supply 20 to the second system 120. In the following description, connecting the inter-system switch 41 means electrically connecting, that is, conducting, the first system 110 and the second system 120. Also, disconnecting the inter-system switch 41 means disconnecting, that is, interrupting, the electrical connection between the first system 110 and the second system 120.

[0022] The first voltage sensor 51 is provided on 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 on the second system 120, detects the voltage of the second system 120, and outputs the detection result to the switch driving unit 3.

[0023] The switch driving unit 3 includes a microcomputer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and various circuits. Note that the switch driving unit 3 may be configured by hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0024] The switch driving unit 3 includes a first detection unit 31 that functions by the CPU executing a program stored in the ROM using the RAM as a work area, and a second detection unit 32, and controls the operation of the power control device 1. Note that the first detection unit 31 may be configured by hardware.

[0025] The first detection unit 31 detects an abnormality in the first system 110 or the second system 120 based on a physical quantity indicating the state of the first system 110 or the second system 120 and a first threshold value. Hereinafter, the case where the physical quantity according to the embodiment is voltage will be described. Also, hereinafter, the case where the abnormality according to the embodiment is a ground fault will be described.

[0026] Note that the physical quantity according to the embodiment is not limited to voltage, and may be a physical quantity other than voltage, such as current or temperature. Also, the abnormality according to the embodiment is not limited to a ground fault, and may be other abnormalities other than a ground fault, such as an abnormal overcurrent state or an abnormal high-temperature state. The cases where the physical quantity is other than voltage and the abnormality is other than a ground fault will be described later.

[0027] The second detection unit 32 identifies whether the system in which an abnormality has been detected by the first detection unit 31 is the first system 110 or the second system 120, based on a physical quantity indicating the state of the first system 110 or the second system 120 and a second threshold value set to have a higher sensitivity for detecting an abnormality than the first threshold value, taking a longer time than the detection time by the first detection unit 31, and then shifts to fail-safe control. Thereby, when a true ground fault has occurred, the power control device 1 can prevent the fail-safe control from being delayed.

[0028] A specific configuration example of the switch driving unit 3 will be described later with reference to FIG. 7. When activated, the switch driving unit 3 connects (turns on) the inter-system switch 41 and disconnects (turns off) the battery switch 42. The switch driving unit 3 detects a ground fault in the first system 110 or the second system 120 based on the detection results input from the first voltage sensor 51 and the second voltage sensor 52. A specific example of the method for detecting a ground fault by the switch driving unit 3 will be described later.

[0029] When the switch driving unit 3 detects a ground fault in the first system 110 or the second system 120, it notifies the automatic driving control device 100 to that effect. When the switch driving unit 3 detects a ground fault in the first system 110 or the second system 120, it outputs an automatic driving prohibition signal indicating that the automatic driving is impossible to the automatic driving control device 100. Also, when the switch driving unit 3 does not detect a ground fault in the first system 110 or the second system 120, it outputs an automatic driving permission signal indicating that the automatic driving is possible to the automatic driving control device 100.

[0030] When a power failure such as a ground fault occurs in the first system 110, the switch driving unit 3 disconnects the inter-system switch 41, connects the battery switch 42, and supplies power from the second power supply 20 to the second load 103. Also, when a power failure such as a ground fault occurs in the second system 120, the switch driving unit 3 disconnects the inter-system switch 41 and supplies power from the first power supply 10 to the first load 101 and the general load 102 with the battery switch 42 being disconnected.

[0031] As a result, even if one of the systems experiences a ground fault during automatic driving, the power supply control device 1 can use the other system to implement the FOP to safely retreat the vehicle to a safe location by the automatic driving control device 100 and stop the vehicle. Next, with reference to FIGS. 2 to 5, the operation of the power supply control device 1 will be described.

[0032] [2. Normal Operation of Power Supply Control Device] During normal times when no ground fault has occurred in the first system 110 and the second system 120, as shown in FIG. 2, the switch drive unit 3 disconnects the battery switch 42 and connects the inter-system switch 41 to supply power from the first power supply 10 to the first load 101, the general load 102, and the second load 103. During normal times when no ground fault has occurred in this way, the switch drive unit 3 outputs an automatic driving permission signal to the automatic driving control device 100.

[0033] [3. Operation of Power Supply Control Device When Ground Fault Occurs] Next, with reference to FIGS. 3 to 5, the operation of the power supply control device 1 when a ground fault occurs will be described. As shown in FIG. 3, 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 toward the ground fault point, so the voltages detected by the first voltage sensor 51 and the second voltage sensor 52 become equal to or lower than the ground fault determination threshold value.

[0034] Therefore, when the first detection unit 31 of the switch drive unit 3 detects by hardware that the voltage detected by the second voltage sensor 52 has become equal to or lower than the first threshold value, which is the ground fault determination threshold value, it tentatively determines that a ground fault 200, 201 has occurred in the first system 110 or the second system 120.

[0035] When the first detection unit 31 tentatively determines that a ground fault 200, 201 has occurred, the switch driving unit 3 outputs an automatic driving prohibition signal to the automatic driving control device 100, immediately shuts off the inter-system switch 41, and connects the battery switch 42. As a result, the connection between the first system 110 and the second system 120 is 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.

[0036] In addition, the first detection unit 31 can also tentatively determine that a ground fault has occurred in the first system 110 or the second system 120 when the voltage detected by at least one of the first voltage sensor 51 or the second voltage sensor 52 becomes equal to or lower than the first threshold value.

[0037] Thereafter, the second detection unit 32 of the switch driving unit 3 identifies whether the system in which the ground fault is detected is the first system 110 or the second system 120 based on the voltage detected by the first voltage sensor 51, the voltage detected by the second voltage sensor 52, and the second threshold value.

[0038] The second threshold value is set so that the sensitivity for detecting an abnormality is higher than that of the first threshold value. Specifically, it is set to a value higher than the second threshold value by a predetermined voltage. Then, the second detection unit 32 identifies the system in which the ground fault has occurred over a time longer than the ground fault detection time by the first detection unit 31 and shifts to fail-safe control.

[0039] At this time, when the voltage detected by the first voltage sensor 51 is equal to or lower than the second threshold value for a predetermined time or longer and the voltage detected by the second voltage sensor 52 returns beyond the second threshold value within a predetermined time, the second detection unit 32 makes a final determination that a ground fault 200 has occurred in the first system 110.

[0040] In this case, as shown in FIG. 4, the second detection unit 32 shifts to fail-safe control, supplies power from the second power source 20 to the second load 103 while maintaining the cut-off state of the inter-system switch 41 and the connection state of the battery switch 42, and notifies the automatic driving control device 100 to that effect. As a result, the automatic driving control device 100 can operate the second load 103 with the power supplied from the second power source 20, and drive the vehicle to a safe location and stop it. Note that the automatic driving control device 100 may be configured to start the evacuation driving when an automatic driving prohibition signal is input from the power control device 1.

[0041] Further, after the first detection unit 31 tentatively determines that a ground fault has occurred in the first system 110 or the second system 120, if the voltage detected by the second voltage sensor 52 is equal to or lower than the second threshold even after a predetermined time has elapsed, and the voltage detected by the first voltage sensor 51 has returned beyond the second threshold within the predetermined time, the second detection unit 32 makes a final determination that a ground fault 201 has occurred in the second system 120.

[0042] In this case, as shown in FIG. 5, the second detection unit 32 shifts to fail-safe control, cuts off the battery switch 42 while continuing the cut-off state of the inter-system switch 41, supplies power from the first power source 10 to the first load 101, and notifies the automatic driving control device 100 to that effect. As a result, the automatic driving control device 100 can operate the first load 101 with the power supplied from the first power source 10, and drive the vehicle to a safe location and stop it. Note that the automatic driving control device 100 may be configured to start the evacuation driving when an automatic driving prohibition signal is input from the power control device 1.

[0043] In this way, the second detection unit 32 identifies the grounded system by comparing the voltage detected by the first voltage sensor 51 and the voltage detected by the second voltage sensor 52 with a second threshold higher than the first threshold, and shifts to fail-safe control. As a result, the power control device 1 can prevent the fail-safe control from being delayed when a true ground fault has occurred.

[0044] In the power control device 1, when the first load 101 or the general load 102, rather than the ground faults 200 and 201, is temporarily in an overload state, the voltage detected by the first voltage sensor 51 may temporarily fall below the ground fault determination threshold. Also, in the power control device 1, when the second load 103 is temporarily in an overload state, the voltage detected by the second voltage sensor 52 may temporarily fall below the ground fault determination threshold.

[0045] In this case, in the power 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 supplied from the second power supply 20 to the second load 103. For this reason, after the switch drive unit 3 tentatively determines that a ground fault 200 or 201 has occurred in the first system 110 or the second system 120, if the voltages detected by the first voltage sensor 51 and the second voltage sensor 52 both exceed the ground fault determination threshold before a predetermined time elapses, it determines that this is a transient voltage drop and there is no abnormality in the power supply. After that, in order to return to the normal operation shown in FIG. 2, the switch drive unit 3 disconnects the battery switch 42 and reconnects the inter-system switch 41.

[0046] [4. Explanation of the First Threshold and the Second Threshold] FIG. 6 is an explanatory diagram of the first threshold and the second threshold according to the embodiment. As shown in FIG. 6, in the power control device 1, for example, when a ground fault or an overload state occurs, the detected voltage (the voltage of the first system 110 or the voltage of the second system 120) by the first detection unit 31 decreases. When the detected voltage decreases to the first threshold at time t1, the first detection unit 31 determines that an abnormality has occurred.

[0047] At this time, even if the second detection unit 32 is detecting the voltage of the first system 110 or the voltage of the second system 120, for example, due to individual differences or the like, it may not detect exactly the same voltage as the first detection unit 31. That is, in the second detection unit 32, a voltage detection error may occur.

[0048] Here, when the first detection unit 31 detects an abnormality at time t1, if the second detection unit 32 detects a voltage higher than the detection voltage of the first detection unit 31 (see the dotted line on the high voltage side shown in FIG. 6), using the same first threshold value as the first detection unit 31 may result in an incorrect determination.

[0049] Specifically, the second detection unit 32 performs an abnormality determination between time t1, when the first detection unit 31 determines an abnormality, and time t2. However, if the voltage detected is the voltage indicated by the dotted line on the high voltage side shown in FIG. 6, since the detection voltage does not drop to the first threshold value, an incorrect determination of no abnormality is made at time t2.

[0050] For this reason, if the second detection unit 32 extends the determination period to, for example, time t3, it can determine that an abnormality has occurred, similar to the first detection unit 31, at time t3. However, if the second detection unit 32 sets a long determination period, the transition to fail-safe control will be delayed.

[0051] Therefore, when the first detection unit 31 detects an abnormality, the second detection unit 32 sets a second threshold value based on the detection value of the physical quantity detected by the second detection unit 32. At this time, the second detection unit 32 sets the second threshold value, which is used as, for example, the ground fault determination threshold value, higher than the first threshold value (for example, +0.5V).

[0052] For example, the second detection unit 32 intentionally causes a ground fault state in the second system 120 by lowering the voltage of the second system 120, such as by cutting off the inter-system switch 41, in a situation where it does not interfere with the running of the vehicle, such as before the power control device 1 is shipped or during a stop after being mounted on the vehicle.

[0053] Then, when the first detection unit 31 detects a ground fault, the second detection unit 32 acquires the detection voltage of the second voltage sensor 52, and sets as the second threshold value a value obtained by adding a predetermined voltage (for example, +0.5V) to the acquired voltage.

[0054] As a result, even when there is an error between the detected voltage and the detected voltage of the first detection unit 31, the second detection unit 32 can set an appropriate second threshold value that can accurately detect a ground fault. Further, in the case shown in FIG. 6, the second detection unit 32 can determine that an abnormality has occurred at time t2 without extending the determination period. Therefore, the power supply control device 1 can suppress the sending of fail-safe control while reliably detecting a ground fault.

[0055] [5. Configuration Example of Switch Driving Unit According to Embodiment] Next, with reference to FIG. 7, a configuration example of the switch driving unit 3 according to the embodiment will be described. FIG. 7 is an explanatory diagram showing a configuration example of the switch driving unit 3 according to the embodiment.

[0056] As shown in FIG. 7, the switch driving unit 3 includes a first detection unit 31, a second detection unit 32, an OR logic circuit 33, and an OR logic circuit 34. The detection results of the voltage of the first system 110 from the first voltage sensor 51 and the detection results of the voltage of the second system 120 from the second voltage sensor 52 are input to the first detection unit 31 and the second detection unit 32.

[0057] When the first detection unit 31 detects a ground fault in the first system 110 or the second system 120, it shuts off the inter-system switch 41 and conducts the battery switch 42. Specifically, when the voltage of the first system 110 or the voltage of the second system 120 becomes equal to or lower than the first threshold value, the first detection unit 31 outputs a primary ground fault detection signal to the second detection unit 32, the OR logic circuit 33, and the OR logic circuit 34. At this time, the first detection unit 31 outputs, for example, a signal of a 50 ms one-shot pulse as the primary ground fault detection signal. When the second detection unit 32 receives the primary ground fault detection signal from the first detection unit 31, it outputs a secondary ground fault detection signal to the OR logic circuit 33 and the OR logic circuit 34.

[0058] The OR logic circuit 34 shuts off the inter-system switch 41 by outputting the primary ground fault detection signal from the first detection unit 31 or the secondary ground fault detection signal from the second detection unit 32 to the inter-system switch 41 as a cut-off signal. The OR logic circuit 33 connects the battery switch 42 by outputting the primary ground fault detection signal from the first detection unit 31 or the secondary ground fault detection signal from the second detection unit 32 to the battery switch 42 as a connection signal.

[0059] Therefore, when a ground fault occurs in the first system 110 or the second system 120, the first detection unit 31 immediately detects the ground fault, shuts off the inter-system switch 41 via the OR logic circuit 34, and connects the battery switch 42 via the OR logic circuit 33.

[0060] With a slight delay, the second detection unit 32 maintains the inter-system switch 41 in the off state via the OR logic circuit 34 and maintains the battery switch 42 in the connected state via the OR logic circuit 33. Also, when a primary ground fault detection signal is input from the first detection unit 31, the second detection unit 32 outputs an automatic operation prohibition signal to the automatic driving control device 100.

[0061] In addition, when a ground fault is detected by the first detection unit 31, the second detection unit 32 identifies whether the system in which the ground fault is detected is the first system 110 or the second system 120. If the ground fault has been eliminated, the second detection unit 32 performs a return control to reconnect the inter-system switch 41 and shut off the battery switch 42.

[0062] Specifically, when detecting the primary ground fault detection signal output from the first detection unit 31, the second detection unit 32 samples the voltages of the first system 110 and the second system 120 at a predetermined period. Then, the second detection unit 32 identifies the system that has sampled a voltage equal to or lower than a second threshold continuously for a predetermined time (for example, 40 ms) or more as the system in which the ground fault is detected.

[0063] Further, when the second detection unit 32 samples a voltage exceeding the second threshold continuously for a predetermined time (e.g., 40 ms) or more in both the first system 110 and the second system 120, it determines that the ground fault is not continuous, and outputs a connection signal (a signal with a logic opposite to the secondary ground fault detection signal) to the OR logic circuit 34. When the connection signal is input from the second detection unit 32, the OR logic circuit 34 outputs the connection signal to the inter-system switch 41 to reconnect the inter-system switch 41. At this time, the second detection unit 32 outputs an automatic operation permission signal to the automatic operation control device 100, and outputs a control signal to the battery switch 42 via the OR logic circuit 33 to cut off the battery switch 42.

[0064] [6. Processing Executed by Switch Driving Unit] Next, with reference to FIG. 8, the processing executed by the switch driving unit 3 of the power supply control device 1 will be described. FIG. 8 is a flowchart showing an example of the processing executed by the switch driving unit 3 of the power supply control device 1 according to the embodiment. The switch driving unit 3 repeatedly executes the processing shown in FIG. 8 during normal operation.

[0065] Specifically, as shown in FIG. 8, the switch driving unit 3 first determines whether an abnormality (e.g., occurrence of a ground fault) is detected based on a physical quantity (e.g., voltage) of the first system 110 or the second system 120 and the first threshold (step S101).

[0066] When the switch driving unit 3 determines that no abnormality is detected (step S101, No), it ends the processing and starts the processing from step S101 again. When the switch driving unit 3 determines that an abnormality is detected (step S101, Yes), it cuts off the inter-system switch 41 and conducts the battery switch 42 (step S102).

[0067] Thereafter, the switch driving unit 3 determines whether it can identify the system in which an abnormality has been detected based on a second threshold value that is more sensitive than the first threshold value (step S103). If the switch driving unit 3 determines that it can identify the system in which an abnormality has been detected (step S103, Yes), that is, if it determines that an abnormality has occurred, it proceeds to fail-safe control (step S104) and ends the process.

[0068] For example, if the switch driving unit 3 determines that a short circuit 200 has occurred in the first system 110, it shuts off the inter-system switch 41 and, with the battery switch 42 turned on, proceeds to fail-safe control to supply power from the second power supply 20 to the second load 103. Also, if the switch driving unit 3 determines that a short circuit 201 has occurred in the second system 120, it shuts off the inter-system switch 41 and the battery switch 42 and proceeds to fail-safe control to supply power from the first power supply 10 to the first load 101 and the general load 102.

[0069] On the other hand, if the switch driving unit 3 determines that it cannot identify the system in which an abnormality has been detected (step S103, No), that is, if it determines that no abnormality has occurred, it turns on the inter-system switch 41, shuts off the battery switch 42, and returns to the normal operation. Thereafter, the switch driving unit 3 starts the process again from step S101.

[0070] [7. Modification Example] The power supply control device 1 may be configured to acquire a current value as a physical quantity indicating the state of the first system 110 or the second system 120 and determine an abnormality in the first system 110 or the second system 120 based on the current value.

[0071] In this case, the power supply control device 1 further includes a first current sensor that detects the current value flowing through the first system 110 and outputs the detection result to the switch driving unit 3, and a second current sensor that detects the current value flowing through the second system 120 and outputs the detection result to the switch driving unit 3.

[0072] When the current value detected by the first current sensor or the second current sensor exceeds the first threshold value, the first detection unit 31 detects the occurrence of an overcurrent abnormality and shuts off the inter-system switch 41. The second detection unit 32 sets a value lower than the first threshold value as the second threshold value.

[0073] For example, the second detection unit 32 operates the DC / DC 11 and increases the current flowing through the first system 110 and the second system 120 in a situation where it does not interfere with the running of the vehicle, such as before the power control device 1 is shipped or during parking after being mounted on the vehicle. Then, when the first detection unit 31 detects an overcurrent abnormality, the second detection unit 32 acquires the detected current value of the first detection unit 31 and sets, as the second threshold value, a value obtained by subtracting a predetermined value from the acquired current value.

[0074] Then, the second detection unit 32 identifies, based on the current value detected by the first current sensor or the second current sensor and the second threshold value, whether the system in which the overcurrent abnormality is detected by the first detection unit 31 is the first system 110 or the second system 120, taking a longer time than the detection time by the first detection unit 31, and shifts to fail-safe control. Thereby, the power control device 1 can prevent the fail-safe control from being delayed when an overcurrent abnormality truly occurs.

[0075] Further, the power control device 1 may be configured to acquire the temperature as a physical quantity indicating the state of the first system 110 or the second system 120 and determine the abnormality of the first system 110 or the second system 120 based on the temperature.

[0076] In this case, the first power source 10 includes a first temperature sensor that detects the temperature of the PbB 12 and outputs it to the switch drive unit 3. The second power source 20 includes a second temperature sensor that detects the temperature of the LiB 21 and outputs it to the switch drive unit 3.

[0077] When the temperature detected by the first temperature sensor or the second temperature sensor exceeds the first threshold value, the first detection unit 31 detects the occurrence of an over-temperature abnormality and shuts off the inter-system switch 41. The second detection unit 32 sets a value lower than the first threshold value as the second threshold value.

[0078] For example, before the shipment of the power control device 1, the second detection unit 32 heats and raises the temperature of the first power supply 10 or the second power supply 20 by a heating device such as a heater. Then, when the first detection unit 31 detects an over-temperature abnormality, the second detection unit 32 acquires the temperature of the first detection unit 31 and sets, as the second threshold value, a value obtained by subtracting a predetermined value from the acquired temperature.

[0079] Then, the second detection unit 32 identifies, based on the temperature detected by the first temperature sensor or the second temperature sensor and the second threshold value, whether the system in which the over-temperature abnormality is detected by the first detection unit 31 is the first system 110 or the second system 120, taking a longer time than the detection time by the first detection unit 31, and shifts to the fail-safe control. Thereby, when the over-temperature abnormality truly occurs, the power control device 1 can prevent the fail-safe control from being delayed.

[0080] Also, the power control device 1 may be configured to determine an over-voltage abnormality of the first system 110 or the second system 120 based on the voltage value of the first system 110 or the second system 120.

[0081] In this case, when the voltage value detected by the first voltage sensor 51 or the second voltage sensor 52 exceeds the first threshold value, the first detection unit 31 detects the occurrence of an over-voltage abnormality and shuts off the inter-system switch 41. The second detection unit 32 sets, as the second threshold value, a value lower than the first threshold value.

[0082] For example, the second detection unit 32 operates the DC / DC 11 in a situation where it does not interfere with the running of the vehicle, such as before the shipment of the power control device 1 or during a stop after being mounted on the vehicle, to raise the voltages of the first system 110 and the second system 120. Then, when the first detection unit 31 detects an over-voltage abnormality, the second detection unit 32 acquires the detected voltage value of the first detection unit 31 and sets, as the second threshold value, a value obtained by subtracting a predetermined value from the acquired current value.

[0083] Then, the second detection unit 32 identifies whether the system in which the overvoltage abnormality has been detected by the first detection unit 31 is the first system 110 or the second system 120, based on the voltage value detected by the first voltage sensor 51 or the second voltage sensor 52 and the second threshold value, taking a longer time than the detection time by the first detection unit 31, and shifts to the fail-safe control. Thereby, when the overvoltage abnormality has truly occurred, the power supply control device 1 can prevent the fail-safe control from being delayed.

[0084] Further effects and modifications can be easily derived by those skilled in the art. For this reason, the broader aspects of the present invention are not limited to the specific details and representative embodiments represented and described as above. Therefore, various changes can be made without departing from the spirit or scope of the general inventive concept defined by the appended claims and their equivalents.

Description of Reference Numerals

[0085] 1 Power supply control device 10 First power supply 11 DC / DC 12 PbB 20 Second power supply 21 LiB 3 Switch drive unit 31 First detection unit 32 Second detection unit 33 OR logic circuit 34 OR logic circuit 41 Inter-system switch 42 Battery switch 51 First voltage sensor 52 Second voltage sensor 100 Automatic driving control device 101 First load 102 General load 103 Second load 110 First system 120 Second system

Claims

1. A first system that supplies the power of a first power source to a first load, A second system that supplies the power of a second power source to a second load, An inter-system switch capable of connecting and disconnecting the first system and the second system, A first detection unit that detects an abnormality in the first system or the second system based on a physical quantity indicating the state of the first system or the second system and a first threshold value, A second detection unit that identifies whether the system in which an abnormality is detected by the first detection unit is the first system or the second system over a time longer than the detection time by the first detection unit based on a second threshold value set so that the sensitivity for detecting an abnormality is higher than that of the physical quantity and the first threshold value, and shifts to fail-safe control A power control device characterized by comprising the above.

2. The physical quantity is a voltage value, The second detection unit, Sets a value higher than the first threshold value as the second threshold value The power control device according to claim 1, characterized by the above.

3. The physical quantity is a current value, The second detection unit, Sets a value lower than the first threshold value as the second threshold value The power control device according to claim 1, characterized by the above.

4. The physical quantity is temperature, The second detection unit, Sets a value lower than the first threshold value as the second threshold value The power control device according to claim 1, characterized by the above.

5. The second detection unit, Sets the second threshold value based on the detected value of the physical quantity detected by the second detection unit when the abnormality is detected by the first detection unit The power control device according to any one of claims 1 to 4, characterized by the above.

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