Power Control Unit

Abstract

To provide a power control device that shortens the time required to supply necessary and sufficient power to a second load after a ground fault in a second system is cleared.SOLUTION: A power control device 1 includes a first system 110 that supplies power 10 of a first power supply to first loads 101 and 102, a second system 120 that supplies power of a second power supply 20 to a second load 103, an inter-system switch 41 provided in a connection path 130 connecting the first system and the second system and capable of connecting and disconnecting the first system and the second system, a supply circuit 53 that supplies a weak current from the second power supply to the second load, and a control unit 3 that shuts off the inter-system switch when a ground fault in the first system or the second system is detected, and supplies a weak current to the second load via the supply circuit when the ground fault in the second system continues.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Conventionally, there has been a redundant power supply system that has a first power supply and a second power supply so that if a power failure such as a ground fault occurs while a vehicle is driving in autonomous mode, the vehicle can be evacuated to a safe location 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 (see, for example, Patent Document 1).

[0003] The redundant power supply system includes a first system connected to a first load for automatic operation, a second system connected to a second load having the same function as the first load, and an inter-system switch capable of connecting and disconnecting the first system and the second system.

[0004] The redundant power supply system normally connects the inter-system switch to supply power from the first power supply to the first load and the second load. If a ground fault occurs in the first system, the redundant power supply system shuts off the inter-system switch to supply power from the second power supply to the second load, and if a ground fault occurs in the second system, the redundant power supply system shuts off the inter-system switch to supply power from the first power supply to the first load.

[0005] In such a redundant power supply system, there are cases where a ground fault occurs in the second system, and the ground fault in the second system is eliminated after the inter-system switch is turned off. In such a case, the superimposed power supply system restores the inter-system switch to conduct electricity, and returns to a normal state in which power is supplied from the first power supply to the first load and the second load. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2018-182864 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the superimposed power supply system has a problem in that it takes time to supply necessary and sufficient power to the second load after the ground fault in the second system is resolved.

[0008] One aspect of the embodiment has been made in consideration of the above, and aims to provide a power supply control device that can shorten the time it takes from the time a ground fault in the second system is resolved to the time when necessary and sufficient power is supplied to the second load. [Means for solving the problem]

[0009] A power supply control device according to an aspect of the embodiment includes a first system, a second system, an inter-system switch, a supply 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 supply circuit supplies a weak current from the second power source to the second load. When a ground fault is detected in the first system or the second system, the control unit cuts off the inter-system switch, and when the ground fault in the second system continues, supplies a weak current to the second load via the supply circuit. Effect of the Invention

[0010] A power supply control device according to an aspect of the embodiment can reduce the time it takes from when a ground fault in the second system is eliminated until when necessary and sufficient power is supplied to the second load. [Brief description of the drawings]

[0011] [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 a flowchart illustrating an example of a process executed by a control unit of the power supply control device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of a power supply control device will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiment described below. 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.

[0013] 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.

[0014] In addition, the power supply control device of the embodiment may be installed in any device that has a first power supply and a second power supply, and that provides backup using the other power supply system in the event of a power failure in either the first power supply or the second power supply.

[0015] [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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] The power supply control device 1 includes a second power supply 20, an inter-system switch 41, a battery switch 42, a backup switch 43, a control unit 3, a first voltage sensor 51, a second voltage sensor 52, and a supply circuit 53. The second power supply 20 is a backup power supply in case the first power supply 10 is unable to supply power. The second power supply 20 includes a lithium ion battery (hereinafter referred to as "LiB21"). Note that the battery of the second power supply 20 may be any secondary battery other than the LiB21.

[0022] 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 battery switch 42 is a switch that can connect and disconnect the LiB 21 and the second system 120. Specifically, the battery switch 42 is a switch that can connect and disconnect the LiB 21 and the backup switch 43 and the supply circuit 53.

[0023] The backup switch 43 is a switch that can connect and disconnect the battery switch 42 and the second system 120. The supply circuit 53 is connected in parallel with the backup switch 43, and adjusts the current and voltage output from the LiB 21 and the current and voltage input to the LiB 21.

[0024] The supply circuit 53 is, for example, a step-down circuit such as a DC / DC, and reduces the amount of current output from the LiB 21 and supplies it to the second system 120. This allows the supply circuit 53 to supply an appropriately adjusted weak current from the second power source 20 to the second system 120. The operation of the supply circuit 53 is controlled by the control unit 3.

[0025] The supply circuit 53 is not limited to DC / DC and may be a resistor. This allows the supply circuit 53 to supply an appropriately adjusted weak current from the second power source 20 to the second system 120 with an inexpensive and simple configuration.

[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 notifies the automatic driving control device 100 of that fact. When the control unit 3 detects a ground fault in the first system 110 or the second system 120, it may notify the automatic driving control device 100 of a state in which automatic driving is impossible. 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 of a state in which 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, and turns on the battery switch 42 and the backup switch 43 to supply 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 battery switch 42 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 6.

[0032] [2. Normal operation of the power supply control device] Under normal circumstances when no ground faults have occurred in the first system 110 and the second system 120, the control unit 3 turns off the battery switch 42, turns on the inter-system switch 41 while keeping the backup switch 43 conductive, as shown in FIG. 2, and supplies power from the first power source 10 to the first load 101, the general load 102, and the second load 103.

[0033] [3. Operation of power supply control device when a ground fault occurs] Next, the operation of the power supply control device 1 when a ground fault occurs will be described with reference to Figures 3 to 6. As shown in Figure 3, in the power supply control device 1, for example, when a ground fault 200 occurs in the first system 110 or when a ground fault 201 occurs in the second system 120, an overcurrent flows toward the ground fault point, and the voltages detected by the first voltage sensor 51 and the second voltage sensor 52 become equal to or lower than the ground fault threshold value.

[0034] Therefore, when the voltage detected by the second voltage sensor 52 becomes equal to or lower than the ground fault threshold value, the control unit 3 provisionally determines that a ground fault 200, 201 has occurred in the first system 110 or the second system 120. Then, when the control unit 3 provisionally determines that a ground fault 200, 201 has occurred, it shuts off the inter-system switch 41 and the backup switch 43, and turns on the battery switch 42.

[0035] As a result, the first system 110 and the second system 120 are disconnected, power is supplied from the first power source 10 to the first system 110, and power is supplied from the second power source 20 to the second system 120 via the supply circuit 53. At this time, the control unit 3 controls the supply circuit 53 to supply a smaller current to the second system 120 than when actually performing backup. This allows the power supply control device 1 to suppress the amount of discharge of the LiB 21.

[0036] When a ground fault 200, 201 occurs in the first system 110 or the second system 120, the voltage detected by the first voltage sensor 51 also becomes equal to or lower than the ground fault threshold. Therefore, the control unit 3 can 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 and the second voltage sensor 52 becomes equal to or lower than the ground fault threshold.

[0037] Thereafter, if the voltage detected by the first voltage sensor 51 is below the ground fault threshold for a predetermined time or more and the voltage detected by the second voltage sensor 52 returns to exceed the ground fault threshold within the predetermined time, the control unit 3 determines that a ground fault 200 has occurred in the first system 110.

[0038] 4, the control unit 3 turns on the backup switch 43, supplies power from the second power source 20 to the second load 103 without passing through the supply circuit 53, and notifies the automatic driving control device 100 of this fact. As a result, the automatic driving control device 100 operates the second load 103 using power supplied from the second power source 20, and can evacuate the vehicle to a safe place and stop the vehicle.

[0039] In addition, after the control unit 3 has provisionally determined 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 below the ground fault threshold and the voltage detected by the first voltage sensor 51 returns to exceed the ground fault threshold within a predetermined time, the control unit 3 finally determines that a ground fault 201 has occurred in the second system 120.

[0040] 5, the control unit 3 supplies power from the first power source 10 to the first load 101 and notifies the automatic driving control device 100 of this fact. As a result, the automatic driving control device 100 operates the first load 101 using the power supplied from the first power source 10, and can evacuate the vehicle to a safe place and stop the vehicle.

[0041] Here, when a typical power supply control device determines that a ground fault 201 has occurred in the second system 120, it shuts off the battery switch 42 to prevent discharging of the LiB 21. However, a typical power supply control device has a problem that it takes time to supply necessary and sufficient power to the second load 103 when the ground fault 201 in the second system 120 is subsequently eliminated and normal operation shown in FIG.

[0042] Specifically, a typical power supply control device does not supply any power to the second load 103 from the time the battery switch 42 is cut off until the ground fault 201 in the second system 120 is resolved and the inter-system switch 41 is turned on to start normal operation. For this reason, a typical power supply control device takes time from the time normal operation is started until the power supplied to the second load 103 gradually increases to a necessary and sufficient amount of power.

[0043] Therefore, when the control unit 3 of the power supply control device 1 detects a ground fault 200, 201 in the first system 110 or the second system 120, it cuts off the inter-system switch 41, and if the ground fault 201 in the second system 120 continues, it supplies a weak current to the second load 103 via the supply circuit 53.

[0044] Specifically, as shown in FIG. 5, after the control unit 3 has determined that a ground fault 201 has occurred in the second system 120, it controls the supply circuit 53 to supply a weak current smaller than the current supplied when determining the ground fault system (see FIG. 3) from the second power source 20 to the second system 120 via the supply circuit 53.

[0045] Then, the control unit 3 acquires the voltage detection result from the second voltage sensor 52 and monitors whether the ground fault 201 of the second system 120 is resolved. At this time, the power supply control device 1 supplies a minimum weak current required for monitoring the ground fault 201 from the second power source 20 to the second system 120, so that the discharge amount of the LiB 21 can be minimized.

[0046] At this time, the control unit 3 can also control the supply circuit 53 to intermittently (for example, once every few seconds) supply a weak current to the second system 120. This allows the control unit 3 to further reduce the discharge amount of the LiB 21.

[0047] 6, when the ground fault in the second system 120 is resolved, the voltage detected by the second voltage sensor 52 recovers. When the voltage detected by the second voltage sensor 52 exceeds the ground fault threshold, the control unit 3 determines that the ground fault 201 in the second system 120 has been resolved.

[0048] When the ground fault 201 in the second system 120 is eliminated, the control unit 3 turns on the inter-system switch 41 and the backup switch 43, turns off the battery switch 42, and returns to the normal operation state shown in FIG.

[0049] At this time, the power supply control device 1 supplies a weak current to the second load 103 before turning on the inter-system switch 41, thereby shortening the time it takes to supply sufficient power to the second load 103 after returning to the normal operating state.

[0050] In this way, if the control unit 3 determines that the ground fault 201 in the second system 120 continues after cutting off the inter-system switch 41, it turns on the battery switch 42 and cuts off the backup switch 43 to supply a weak current to the second load 103 via the supply circuit 53.

[0051] As a result, when a ground fault 201 occurs in the second system 120 and then the ground fault 201 is resolved, the power supply control device 1 can reduce the time it takes to supply necessary and sufficient power to the second load 103.

[0052] Furthermore, in the power supply control device 1, when the first load 101 or the general load 102 temporarily falls into an overload state, rather than the ground faults 200 and 201, the voltage detected by the first voltage sensor 51 may temporarily fall below the ground fault threshold. Furthermore, in the power supply control device 1, when the second load 103 temporarily falls into an overload state, the voltage detected by the second voltage sensor 52 may temporarily fall below the ground fault threshold.

[0053] In this case, in the power supply control device 1, power is continuously supplied from the first power source 10 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 via the supply circuit 53. Therefore, after provisionally determining that a ground fault 200, 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 return to exceeding the ground fault threshold before a predetermined time has elapsed, the control unit 3 officially determines that the voltage drop is temporary and that there is no abnormality in the power supply. Thereafter, in order to return to the normal operation shown in FIG. 2, the control unit 3 turns off the battery switch 42 and re-connects the inter-system switch 41 and the backup switch 43.

[0054] [4. Processing performed by the control unit] Next, a process executed by the control unit 3 of the power supply control device 1 according to the embodiment will be described with reference to Fig. 7. Fig. 7 is a flowchart showing an example of a process executed by the control unit of the power supply control device according to the embodiment.

[0055] The control unit 3 repeatedly executes the process shown in Fig. 7 during normal operation. Specifically, as shown in Fig. 7, the control unit 3 first determines whether or not a ground fault has occurred (step S101). When the control unit 3 determines that a ground fault has not occurred (step S101, No), it ends the process and starts the process again from step S101.

[0056] Furthermore, when the control unit 3 determines that a ground fault has occurred (step S101, Yes), it turns off the system switch 41 (step S102), turns on the battery switch 42 (step S103), and turns off the backup switch 43 (step S104). Then, the control unit 3 controls the supply circuit 53 to supply a current from the second power source 20 to the second load 103 via the supply circuit 53 (step S105).

[0057] Thereafter, the control unit 3 determines whether the power supply system has returned to normal (step S106). If the control unit 3 determines that the power supply system has returned to normal (step S106, Yes), the control unit 3 proceeds to step S110. If the control unit 3 determines that the power supply system has not returned to normal (step S106, No), the control unit 3 determines whether a ground fault has occurred in the second system 120 (step S107).

[0058] If the control unit 3 determines that the fault is not a ground fault in the second system, that is, that the fault is a ground fault in the first system 110 (step S107, No), it turns on the backup switch 43 (step S113) and supplies current from the second power source 20 directly to the second load 103 without going through the supply circuit 53, and then ends the processing.

[0059] Furthermore, if the control unit 3 determines that there is a ground fault in the second system 120 (step S107, Yes), it controls the supply circuit 53 to supply a weak current from the second power source 20 to the second load 103 via the supply circuit 53 (step S108).

[0060] Thereafter, the control unit 3 determines whether or not the ground fault in the second system 120 has been eliminated (step S109). When the control unit 3 determines that the ground fault in the second system 120 has not been eliminated (step S109, No), the control unit 3 shifts the process to step S108.

[0061] Furthermore, when the control unit 3 determines that the ground fault in the second system 120 has been resolved (step S109, Yes), it turns on the system switch 41 (step S110), turns off the battery switch 42 (step S111), and turns on the backup switch 43 (step S112). This causes the power supply control device 1 to return to normal operation. Then, the control unit 3 ends the process and starts the process again from step S101.

[0062] 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]

[0063] 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 Battery switch 43 Backup switch 51 First voltage sensor 52 Second voltage sensor 53 Supply circuit 100 Automatic driving control device 101 1st load 102 General load 103 2nd load 110 1st system 120 2nd system

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, the inter-system switch being capable of connecting and disconnecting the first system and the second system; a supply circuit for supplying a weak current from the second power source to the second load; a control unit that, when detecting a ground fault in the first system or the second system, shuts off the inter-system switch, and, when the ground fault in the second system continues, supplies a weak current to the second load via the supply circuit; A power supply control device comprising:

2. a battery switch capable of connecting and disconnecting the second power source to the second system; a backup switch connected in parallel to the supply circuit provided between the battery switch and the second system; Equipped with The control unit is If it is determined that the ground fault in the second system continues after the inter-system switch is cut off, the battery switch is made conductive, the backup switch is cut off, and a weak current is supplied to the second load via the supply circuit.

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

3. The supply circuit is a step-down circuit.

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

4. The supply circuit is a resistor 3. The power supply control device according to claim 1 or 2.

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