Power supply control device and power supply control method

Abstract

To provide a power supply controller and a power supply control method for reducing inrush current when an inter-system switch is conducted again.SOLUTION: A power supply controller 1 comprises: a first system 110 which supplies power of a first power supply 10 to a first load 101; a second system 120 which supplies power of a second power supply 20 to a second load 103; an inter-system switch 41 which is provided on a connection path 130 for connecting the first system with the second system to connect / disconnect the first system and the second system; a switch 42 for a first battery which can connect / disconnect the first power supply with / from the first system; a switch 43 for a second battery which can connect / disconnect the second power supply with / from the second system; a power storage circuit 6 which is provided between the switch for the first battery and the inter-system switch; and a control unit 3 which blocks the inter-system switch and the switch for the first battery when an abnormality of the systems is detected, and restores the inter-system switch, the switch for the first battery and the switch for the second battery to states before detection of the abnormality when it is determined that there is no ground fault.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Conventionally, there has been a redundant power supply system that is equipped with a first power supply and a second power supply so that, even if a power failure occurs while a vehicle is traveling in autonomous driving mode, the vehicle can be evacuated to a safe place and stopped.If a ground fault occurs in one of the power supply systems, the other power supply system supplies power to on-board equipment (load) for autonomous driving.

[0003] The redundant power supply system includes a first system that supplies power from a first power source to a first load for automatic operation, and a second system that supplies power from a second power source to a second load having the same function as the first load. The redundant power supply system further includes an inter-system switch that can connect and disconnect the first system and the second system, and a battery switch that can connect and disconnect the second power source and the second system.

[0004] The redundant power supply system normally supplies power from the first power supply to the first load and the second load by conducting the inter-system switch and the battery switch, and when, for example, the voltage of the first power supply or the second power supply falls below the ground fault threshold, it determines that a ground fault has occurred and cuts off the inter-system switch. As a result, when a ground fault occurs in one power supply system, the redundant power supply system can perform backup control for evacuation driving by supplying power to the load for automatic driving using the other power supply system.

[0005] In such a redundant power supply system, for example, when the first load or the second load is in an overload state, the voltage of the first power supply or the second power supply may temporarily drop below the ground fault threshold even if a ground fault does not occur. In this case, if the redundant power supply system erroneously determines that an overload state has occurred as a ground fault and unnecessarily shuts off the inter-system switch, the vehicle will stop automatic driving that can continue normally and switch to evacuation driving.

[0006] For this reason, there is a power supply system that shuts off the inter-system switch when the voltage of the first power supply or the second power supply falls below a first threshold, and then re-opens the inter-system switch if the voltage of the first power supply or the second power supply does not drop to a second threshold lower than the first threshold before a predetermined time has elapsed (see, for example, Patent Document 1).

[0007] According to such a power supply system, even if the power supply voltage temporarily drops due to the occurrence of an overload condition and the inter-system switch is shut off, if the power supply voltage subsequently returns to a normal voltage, the inter-system switch will be turned on again, thereby making it possible to minimize the interruption time of automatic operation. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2019-62727 A Summary of the Invention [Problem to be solved by the invention]

[0009] However, in a redundant power supply system, when the inter-system switch is turned on again, an inrush current may occur according to the voltage difference between the first and second power supplies. If the inrush current is large, it may cause the inter-system switch to fail.

[0010] One aspect of the embodiment has been made in consideration of the above, and aims to provide a power supply control device and a power supply control method that can reduce inrush current when an inter-system switch is re-connected. [Means for solving the problem]

[0011] A power supply control device according to one aspect of the embodiment includes a first system, a second system, an inter-system switch, a first battery switch, a second battery switch, a storage circuit, and a control 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 inter-system switch is provided in a connection path connecting the first system and the second system, and is capable of connecting and disconnecting the first system and the second system. The first battery switch is capable of connecting and disconnecting the first power source to the first system. The second battery switch is capable of connecting and disconnecting the second power source to the second system. The storage circuit is provided between the first battery switch and the inter-system switch. When the control unit detects an abnormality in the first system or the second system, it cuts off the system-to-system switch and the first battery switch, turns on the second battery switch, and determines whether or not there is a ground fault based on the power of the storage circuit and the second power source, and when it determines that there is no ground fault, it restores the system-to-system switch, the first battery switch, and the second battery switch to their states before the abnormality was detected. Effect of the Invention

[0012] A power supply control device and a power supply control method according to an aspect of the embodiment have an effect of reducing an inrush current when an inter-system switch is re-connected, thereby preventing a failure of the inter-system switch. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is an explanatory diagram illustrating an example of the configuration of a power supply control device according to an embodiment. [Diagram 2] FIG. 2 is an explanatory diagram illustrating an example of the operation of the power supply control device according to the embodiment. [Diagram 3] FIG. 3 is an explanatory diagram illustrating an example of the operation of the power supply control device according to the embodiment. [Figure 4] FIG. 4 is an explanatory diagram illustrating an example of the operation of the power supply control device according to the embodiment. [Diagram 5] FIG. 5 is an explanatory diagram illustrating an example of the operation of the power supply control device according to the embodiment. [Figure 6] FIG. 6 is an explanatory diagram illustrating an example of the operation of the power supply control device according to the embodiment. [Figure 7] FIG. 7 is an explanatory diagram illustrating an example of the operation of the power supply control device according to the embodiment. [Figure 8] FIG. 8 is an explanatory diagram illustrating an example of the operation of the power supply control device according to the embodiment. [Figure 9] FIG. 9 is a flowchart illustrating an example of processing executed by a control unit of the power supply control device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of a power supply control device and a power supply control method will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following embodiment. In the following, a power supply control device that is mounted on a vehicle with an automatic driving function and supplies power to a load will be described as an example, but the power supply control device according to the embodiment may be mounted on a vehicle that does not have an automatic driving function.

[0015] Further, 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 is run by an internal combustion engine.

[0016] [1. Power supply control device configuration] Fig. 1 is an explanatory diagram showing a configuration example of a power supply control device according to an embodiment. As shown in Fig. 1, 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 operation 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 (described later) to the second load 103.

[0017] The first load 101 includes a load for autonomous driving. For example, the first load 101 includes a steering motor, an electric brake device, an in-vehicle camera, a radar, etc. that operate during autonomous driving. The general load 102 includes, for example, a display, an air conditioner, an audio device, a video device, various lights, etc.

[0018] The second load 103 has the same function as the first load 101. The second load 103 includes devices that operate during automatic driving, such as a steering motor, an electric brake device, an in-vehicle camera, and a radar. The first load 101, the general load 102, and the second load 103 operate with power supplied from the power supply control device 1. The automatic driving control device 100 is a device that operates the first load 101 or the second load 103 to control the automatic driving of a vehicle.

[0019] 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.

[0020] The DC / DC 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 110. The generator is, for example, an alternator that converts the kinetic energy of a traveling vehicle into electricity to generate power. The high-voltage battery is, for example, a battery for driving the vehicle that is mounted on an electric vehicle or a hybrid vehicle.

[0021] When the first power source 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 second load 103, and charges the second power source 20 described later.

[0022] The power supply control device 1 includes a second power supply 20, an inter-system switch 41, a first battery switch 42, a second battery switch 43, a control unit 3, a first voltage sensor 51, a second voltage sensor 52, and a storage circuit 6.

[0023] 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"). Note that the battery of the second power source 20 may be any secondary battery other than the LiB21.

[0024] The inter-system switch 41 is provided in a connection path 130 that connects the first system 110 and the second system 120, and is a switch that can connect and disconnect the first system 110 and the second system 120. The first battery switch 42 is a switch that can connect and disconnect the first power source 10 to the first system 110. The second battery switch 43 is a switch that can connect and disconnect the second power source 20 to the second system 120.

[0025] The storage circuit 6 is provided between the first battery switch 42 and the inter-system switch 41. The storage circuit 6 is, for example, a capacitor, and is connected between the wiring connecting the first battery switch 42 and the inter-system switch 41 and the ground.

[0026] 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 control 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 control unit 3.

[0027] The control 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 control unit 3 may be configured with hardware such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA).

[0028] The control unit 3 controls the operation of the power supply control device 1 by causing the CPU to execute a program stored in the ROM using the RAM as a work area. The control 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 a method for detecting a ground fault by the control unit 3 will be described later.

[0029] When the control unit 3 detects a ground fault in the first system 110 or the second system 120, it determines the system in which the ground fault has occurred and notifies the automatic driving control device 100 of the determination result. When the control unit 3 determines the system in which the ground fault has occurred, it may notify the automatic driving control device 100 that automatic driving is not possible. When the control unit 3 does not detect a ground fault in the first system 110 or the second system 120, it may notify the automatic driving control device 100 that automatic driving is possible.

[0030] When a power failure such as a ground fault occurs in the first system 110, the control unit 3 cuts off the system-to-system switch 41, turns on the second battery switch 43, 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 control unit 3 cuts off the system-to-system switch 41, and supplies power from the first power source 10 to the first load 101 and the general load 102 with the second battery switch 43 cut off.

[0031] As a result, even if a ground fault occurs in one of the systems during automatic driving, the power supply control device 1 can use the other system and cause the vehicle to retreat to a safe place and stop by the automatic driving control device 100. Next, the operation of the power supply control device 1 will be described with reference to Figs. 2 to 8.

[0032] [2. Normal operation of the power supply control device] 2, during normal operation when no ground fault occurs in the first system 110 and the second system 120, the control unit 3 turns off the second battery switch 43 and turns on the first battery switch 42 and the inter-system switch 41 to supply power from the first power source 10 to the first load 101, the general load 102, and the second load 103. At this time, the storage circuit 6 is charged by the power supplied from the first power source 10.

[0033] [3. Earth fault detection operation of power supply control device] Next, the ground fault determination operation of the power supply control device 1 will be described with reference to Fig. 3 to Fig. 8. Fig. 3 to Fig. 8 are explanatory diagrams showing an example of the operation of the power supply control device according to the embodiment. The control unit 3 detects an abnormality 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 ground fault threshold value. At this time, the control unit 3 provisionally determines that a ground fault has occurred in the first system 110 or the second system 120.

[0034] As shown in FIG. 3, when the control unit 3 detects an abnormality in the first system 110 or the second system 120, it turns off the inter-system switch 41 and the first battery switch 42, and turns on the second battery switch 43.

[0035] At this time, as shown in Fig. 4, if a ground fault 200 occurs in the first system 110, an overcurrent flows from the storage circuit 6 to the ground fault point. Therefore, the first voltage sensor 51 continuously detects a voltage equal to or lower than the ground fault threshold. In contrast, since no ground fault occurs in the second system 120, the second voltage sensor 52 detects a voltage applied from the second power source 20 that is higher than the ground fault threshold.

[0036] Therefore, the control unit 3 turns off the inter-system switch 41 and the first battery switch 42, and then turns off the second battery switch 43.If the detection result of the first voltage sensor 51 is below the ground fault threshold for a predetermined time or more, and the detection result of the second voltage sensor 52 exceeds the ground fault threshold within the predetermined time, then the control unit 3 makes a final determination that there is a ground fault 200 in the first system 110, and notifies the automatic driving control device 100 of the determination result.

[0037] At this time, the control unit 3 notifies the automatic driving control device 100 that a ground fault 200 has occurred in the first system 110 and that backup control has been started to supply power from the second power source 20 to the second load 103. As a result, the automatic driving control device 100 can operate the second load 103 using power supplied from the second power source 20 and evacuate the vehicle to a safe place and stop the vehicle.

[0038] 5, if a ground fault 201 occurs in the second system 120, an overcurrent flows from the second power source 20 to the ground fault point. Therefore, the second voltage sensor 52 continuously detects a voltage equal to or lower than the ground fault threshold. In contrast, since no ground fault occurs in the first system 110, the first voltage sensor 51 detects a voltage higher than the ground fault threshold due to the voltage applied from the storage circuit 6.

[0039] Therefore, the control unit 3, after provisionally determining that the inter-system switch 41 and the first battery switch 42 are shut off and that the second battery switch 43 is conductive, determines that there is a ground fault 201 in the second system 120 if the detection result of the second voltage sensor 52 is equal to or less than the ground fault threshold for a predetermined time or more and the detection result of the first voltage sensor 51 exceeds the ground fault threshold for the predetermined time or more, and notifies the automatic driving control device 100 of the determination result. As a result, the automatic driving control device 100 can operate the first load 101 with power supplied from the first power source 10 and drive the vehicle to a safe place and stop it.

[0040] 6, the control unit 3 then turns on the first battery switch 42, supplies power from the first power source 10 to the first load 101 and the general load 102, and turns off the second battery switch 43. At this time, in the power supply control device 1, the voltage of the first system 110 has dropped when the first battery switch 42 is turned on because the power supply control device 1 has performed a ground fault determination for the first system 110 using the power of the storage circuit 6.

[0041] Therefore, when the power supply control device 1 turns on the first battery switch 42 when the voltage of the first system 110 is low, an inrush current 202 flows from the first power source 10 to the first system 110. However, since the first system 110 is provided with the storage circuit 6, the inrush current 202 can be reduced.

[0042] Specifically, in the power supply control device 1, the parasitic resistance of the conductive first battery switch 42 and the capacitor of the storage circuit 6 function as an RC filter (low-pass filter), so that high-frequency components can be removed from the inrush current 202 and power can be supplied to the first load 101. This makes it possible to prevent failure of the first battery switch 42.

[0043] In addition, in the power supply control device 1, when the first load 101 or the general load 102 is in an overload state, rather than when the ground faults 200, 201 occur, the voltage detected by the first voltage sensor 51 may temporarily become equal to or lower than the ground fault threshold. In addition, in the power supply control device 1, when the second load 103 is in an overload state, the voltage detected by the second voltage sensor 52 may temporarily become equal to or lower than the ground fault threshold.

[0044] 3, in the power supply control device 1, power is supplied from the storage circuit 6 to the first load 101 and the general load 102, and power is supplied from the second power source 20 to the second load 103. Therefore, the first voltage sensor 51 detects a voltage higher than the ground fault threshold when a voltage is applied from the storage circuit 6. Also, the second voltage sensor 52 detects a voltage higher than the ground fault threshold when a voltage is applied from the second power source 20.

[0045] Therefore, after the control unit 3 provisionally determines that a ground fault has occurred in the first system 110 or the second system 120, if the detection results of the first voltage sensor 51 and the second voltage sensor 52 both exceed the ground fault threshold value within a predetermined time, the control unit 3 officially determines that no ground faults 200, 201 have occurred and restores normal operation.

[0046] Specifically, when the control unit 3 determines that there are no ground faults 200, 201, first, the control unit 3 turns on the inter-system switch 41 as shown in Fig. 7. At this time, in the power supply control device 1, the voltage of the first system 110 has dropped when the inter-system switch 41 is turned on because the power supply control device 1 has performed the ground fault determination for the first system 110 using the power of the storage circuit 6.

[0047] For this reason, when the power supply control device 1 turns on the inter-system switch 41 while the voltage of the first system 110 is low, an inrush current 203 flows from the second power source 20 to the connection path 130. However, since the first system 110 is provided with the storage circuit 6, the inrush current 203 can be reduced and failure of the inter-system switch 41 can be prevented.

[0048] Specifically, in the power supply control device 1, the parasitic resistance of the conductive inter-system switch 41 and the capacitor of the storage circuit 6 function as an RC filter (low-pass filter), so that high-frequency components can be removed from the inrush current 203 to supply power to the first load 101. After that, as shown in Fig. 8, the control unit 3 makes the first battery switch 42 conductive and cuts off the second battery switch 43 to restore normal operation.

[0049] At this time, in the power supply control device 1, the inter-system switch 41 is conductive before the first battery switch 42 is made conductive, so the storage circuit 6 is charged by the second power source 20 and the voltage of the first system 110 is in a boosted state. Therefore, when the first battery switch 42 is made conductive, the power supply control device 1 can reduce the inrush current 202 flowing from the first power source 10 to the first system 110, and can prevent the first battery switch 42 from failing.

[0050] Furthermore, when the first battery switch 42 is conductive and the voltage of the first power source 10 is higher than the voltage of the second power source 20, the parasitic resistance of the conductive first battery switch 42 and the capacitor of the storage circuit 6 function as an RC filter as described above. This allows the power supply control device 1 to remove high-frequency components from the inrush current 202 and supply power to the first load 101.

[0051] Here, in order for the control unit 3 to return to normal operation, the system switch 41 is turned on, then the first battery switch 42 is turned on, and the second battery switch 43 is turned off, but this is just one example.

[0052] When the control unit 3 determines that there are no ground faults 200, 201 and returns to normal operation, it may simultaneously make the first battery switch 42 and the inter-system switch 41 conductive, and simultaneously make the second battery switch 43 conductive.

[0053] At this time, in the power supply control device 1, an inrush current 202 flows from the first power source 10 to the first system 110. However, as described above, the parasitic resistance of the conductive first battery switch 42 and the capacitor of the storage circuit 6 function as an RC filter, thereby reducing the inrush current 202.

[0054] Moreover, in this case, the power supply control device 1 does not charge the storage circuit 6 using the second power supply 20 before turning on the first battery switch 42 and the system switch 41, thereby minimizing the discharge of the second power supply 20.

[0055] [4. Processing performed by the control unit of the power supply control device] Next, an example of processing executed by the control unit according to the embodiment will be described with reference to Fig. 9. Fig. 9 is a flowchart showing an example of processing executed by the control unit of the power supply control device according to the embodiment. The control unit 3 according to the embodiment repeatedly executes the processing shown in Fig. 9 during normal operation.

[0056] 9, the control unit 3 first determines whether or not an abnormality has been detected in the first system 110 or the second system 120 (step S101). When the control unit 3 determines that an abnormality has not been detected in the first system 110 or the second system 120 (step S101, No), the control unit 3 ends the process and restarts the process from step S101.

[0057] Furthermore, when the control unit 3 determines (provisionally determines) that an abnormality has been detected in the first system 110 or the second system 120 (step S101, Yes), it turns off the inter-system switch 41 and the first battery switch 42 (step S102) and turns on the second battery switch 43 (step S103). After that, the control unit 3 determines (mainly determines) whether or not there is a ground fault 200, 201 (step S104).

[0058] When the control unit 3 determines that there is a ground fault 200, 201 (step S104, No), it determines whether or not there is a ground fault 201 in the second system 120 (step S108). When the control unit 3 determines that there is a ground fault 201 in the second system 120 (step S108, Yes), it notifies the automatic driving control device 100 of that effect (step S109), and the process proceeds to step S106.

[0059] Furthermore, when the control unit 3 determines that the fault is not the ground fault 201 in the second system 120, that is, that the fault is the ground fault 200 in the first system 110 (step S108, No), it notifies the automatic driving control device 100 of that effect (step S110), ends the process, and restarts the process from step S101. As a result, evacuation travel control by the second system 120 is performed.

[0060] Furthermore, if the control unit 3 determines that there is no ground fault 200, 201 (step S104, Yes), it turns on the system switch 41 (step S105), and then turns on the first battery switch 42 (step S106).Then, the control unit 3 turns off the second battery switch 43 (step S107), ends the process, and restarts the process from step S101.

[0061] After the control unit 3 has made the system switch 41 conductive (step S105), it may simultaneously make the first battery switch 42 conductive (step S106) and cut off the second battery switch 43 (step S107).

[0062] Furthermore, the control unit 3 may simultaneously perform the operations of turning on the inter-system switch 41 (step S105), turning on the first battery switch 42 (step S106), and cutting off the second battery switch 43 (step S107). This allows the power supply control device 1 to minimize the discharge of the second power supply 20 when returning to normal operation.

[0063] Further advantages and modifications may readily occur to those skilled in the art. Thus, 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 equivalents thereof. [Explanation of symbols]

[0064] 1 Power supply control device 10 1st power supply 11 DC / DC 12 PbB 20 2nd power supply 21 LiB 3. Control Unit 41 Intersystem switch 42 First battery switch 43 Second battery switch 51 First voltage sensor 52 Second voltage sensor 6. Storage Circuit 100 Automatic driving control device 101 1st load 102 General load 103 2nd load 110 1st system 120 2nd system 130 Connection Path 200,201 Earth fault 202,203 Inrush current

Claims

1. a first system that supplies power from a first power source to a first load; a second system that supplies power from a second power source to a second load; an inter-system switch provided in a connection path connecting the first system and the second system and capable of connecting and disconnecting the first system and the second system; a first battery switch capable of connecting and disconnecting the first power source to the first system; a second battery switch capable of connecting and disconnecting the second power source to the second system; a storage circuit provided between the first battery switch and the system switch; a control unit that, when detecting an abnormality in the first system or the second system, shuts off the inter-system switch and the first battery switch, turns on the second battery switch, and determines whether or not there is a ground fault based on the power of the storage circuit and the second power source, and, when determining that there is no ground fault, restores the inter-system switch, the first battery switch, and the second battery switch to states before the detection of the abnormality; A power supply control device comprising:

2. The control unit is When it is determined that there is no ground fault, the first battery switch and the inter-system switch are simultaneously turned on, and the second battery switch is simultaneously turned off.

2. The power supply control device according to claim 1 .

3. The control unit is When it is determined that there is no ground fault, the system switch is turned on, and then the first battery switch is turned on and the second battery switch is turned off.

2. The power supply control device according to claim 1 .

4. a first system that supplies power from a first power source to a first load; a second system that supplies power from a second power source to a second load; an inter-system switch provided in a connection path connecting the first system and the second system and capable of connecting and disconnecting both systems; a first battery switch capable of connecting and disconnecting the first power source to the first system; a second battery switch capable of connecting and disconnecting the second power source to the second system; a storage circuit provided between the first battery switch and the system switch; A control unit of a power supply control device comprising: When an abnormality is detected in the first system or the second system, the system-to-system switch and the first battery switch are cut off, the second battery switch is turned on, and the presence or absence of a ground fault is determined based on the power of the storage circuit and the second power source, and when it is determined that there is no ground fault, the system-to-system switch, the first battery switch, and the second battery switch are returned to a state before the abnormality was detected. A power supply control method comprising:

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