Power supply control apparatus and power supply control method

Abstract

A power supply control device includes a first system, a second system, an inter-system switch, a battery switch, and a controller. In response to detecting an abnormality in a first power supply or a second power supply, the controller turns off the inter-system switch that connects and disconnects systems and turns on the battery switch that connects the second power supply to the second system and disconnects the second power supply from the second system, and thereafter turns on the inter-system switch and turns off the battery switch in response to determining that there is no abnormality in the power supplies. Before turning on the inter-system switch, the controller performs convergence control when a voltage difference between the power supplies is equal to or greater than a threshold value, and after determining that there is no abnormality in the power supplies, the controller keeps the battery switch off while performing the convergence control.

Description

TECHNICAL FIELD

[0001] Embodiments of the present disclosure relate to a power supply control device and a power supply control method. BACKGROUND

[0002] In the related art, there is a redundant power supply system that has a first power supply and a second power supply in order for one of the power supply systems to supply power to a self-contained device (load) for automatic driving in the event of a ground fault of the other power supply system, so that even when a power failure occurs while the vehicle is traveling by automatic driving, the redundant power supply system is able to cause the vehicle to perform an evacuation run to reach a safe place and stop there.

[0003] The redundant power supply system has a first system for supplying power of the first power supply to a first load for automatic driving, and a second system for supplying power of the second power supply to a second load whose function is the same as that of the first load. Further, the redundant power supply system has an inter-system switch capable of connecting and disconnecting the first system and the second system to and from each other, and a battery switch capable of connecting and disconnecting the second power supply and the second system to and from each other.

[0004] The redundant power supply system generally keeps the inter-system switch and the battery switch in a conduction state to supply power from the first power supply to the first load and the second load, and for example, if the voltage of the first power supply or the second power supply becomes equal to or lower than a ground fault threshold value, the redundant power supply system determines a ground fault and turns off the inter-system switch. Therefore, if a ground fault occurs in one power supply system, the redundant power supply system supplies power to the load for automatic driving through the other power supply system, whereby it is able to perform backup control to travel for evacuation.

[0005] In the 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 and the second power supply can temporarily become equal to or lower than the ground fault threshold value even if no ground fault has occurred. In this case, if the redundant power supply system misjudges the occurrence of the overload state as a ground fault and unnecessarily turns off the inter-system switch, the vehicle stops the automatic driving that can normally continue and shifts to travel for evacuation.

[0006] Therefore, if the voltage of the first power supply or the second power supply becomes lower than a first threshold value, there is a power supply system for turning off the inter-system switch, and thereafter if the voltage of the first power supply or the second power supply drops to a second threshold value that is smaller than the first threshold value within a predetermined time, the inter-system switch is turned on again (see, for example, JP-A-2019-62727).

[0007] According to the power supply system, for example, even if the voltage of the power supply temporarily drops due to the occurrence of an overload state, and the inter-system switch is turned off, after that, if the voltage of the power supply returns to a normal voltage, the inter-system switch is turned on again. Therefore, it is possible to minimize the autonomous driving interruption time. SUMMARY

[0008] However, in the power supply system, since the second power supply discharges from when the inter-system switch is turned off to when the inter-system switch is turned on again, the amount of charge in the second power supply decreases when the inter-system switch is turned on again.

[0009] One aspect of an embodiment is presented in view of such a situation, and aims to provide a power supply control device and a power supply control method capable of suppressing a voltage drop in a second power supply when an inter-system switch is turned on again.

[0010] A power supply control device according to one aspect of an embodiment includes: a first system configured to supply power of a first power supply to a first load; a second system configured to supply power of a second power supply to a second load; an inter-system switch configured to connect and disconnect the first system and the second system to and from each other; a battery switch configured to connect and disconnect the second power supply to and from the second system; and a controller configured to turn off the inter-system switch and turn on the battery switch in response to detecting an abnormality in at least one of the first power supply or the second power supply, and thereafter turn on the inter-system switch again and turn off the battery switch in response to determining that there is no abnormality in the first power supply or the second power supply. Before turning on the inter-system switch again, in a case where a voltage difference between the first power supply and the second power supply is equal to or greater than a threshold value, the controller performs convergence control so that the voltage difference becomes less than the threshold value, and after determining that there is no abnormality in the first power supply or the second power supply, the controller keeps the battery switch turned off while the convergence control is performed.

[0011] The power supply control device and the power supply control method according to aspects of the embodiment have an effect of being able to suppress a decrease in the amount of charge in the second power supply when the inter-system switch is turned on again. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is an explanatory diagram illustrating a configuration example of a power supply control device according to an embodiment.

[0013] Figure 2 is an explanatory diagram illustrating an operation example of a power supply control device according to an embodiment.

[0014] Figure 3 is an explanatory diagram illustrating another operation example of a power supply control device according to an embodiment.

[0015] Figure 4is a explanatory diagram illustrating another operation example of the power supply control apparatus according to the embodiment.

[0016] Figure 5 is a explanatory diagram illustrating another operation example of the power supply control apparatus according to the embodiment.

[0017] Figure 6 is a explanatory diagram illustrating another operation example of the power supply control apparatus according to the embodiment.

[0018] Figure 7 is a explanatory diagram illustrating another operation example of the power supply control apparatus according to the embodiment.

[0019] Figure 8 is a explanatory diagram illustrating another operation example of the power supply control apparatus according to the embodiment.

[0020] Figure 9 is a flowchart illustrating an example of processing performed by the controller of the power supply control apparatus according to the embodiment. DETAILED DESCRIPTION

[0021] Hereinafter, embodiments of the power supply control apparatus and the power supply control method will be described in detail with reference to the accompanying drawings. However, the present application is not limited to the following embodiments. Hereinafter, a power supply control apparatus installed on a vehicle having an automatic driving function so as to supply power to a load will be described as an example; however, the power supply control apparatus according to the embodiment can also be installed on a vehicle that does not have an automatic driving function.

[0022] Hereinafter, a case in which the vehicle on which the power supply control apparatus is installed is a hybrid vehicle will be described. However, the vehicle on which the power supply control apparatus can be installed can be an engine vehicle that travels by an internal combustion engine.

[0023] 1. Configuration of the power supply control apparatus

[0024] Figure 1 is a explanatory diagram illustrating an example of the configuration of the power supply control apparatus according to the embodiment. As shown in Figure 1 the power supply control apparatus 1 according to the embodiment is connected to a first power supply 10, a first load 101, a general-purpose load 102, a second load 103, and an automatic driving control apparatus 100. The power supply control apparatus 1 includes a first system 110 for supplying power of the first power supply 10 to the first load 101 and the general-purpose load 102, and a second system 120 for supplying power of a second power supply 20 (to be described below) to the second load 103.

[0025] The first load 101 includes loads for automatic driving. For example, the first load 101 includes a steering motor, an electric brake device, a self-mounted camera, a radar, and the like, which operate during automatic driving. The general load 102 includes, for example, a display, an air conditioner, an audio system, a video system, various lamps, and the like.

[0026] The second load 103 has the same function as that of the first load 101. The second load 103 includes devices, such as a steering motor, an electric brake device, a self-mounted camera, and a radar, which operate during automatic driving. The first load 101, the general load 102, and the second load 103 operate by electric power supplied by the power supply control device 1. The automatic driving control device 100 is a device that performs automatic driving control of a vehicle by operating the first load 101 or the second load 103.

[0027] The first power supply 10 includes a DC-DC converter (hereinafter, referred to as "DC / DC 11") and a lead battery (hereinafter, referred to as "PbB 12"). However, the battery for the first power supply 10 can be any secondary battery other than the PbB 12.

[0028] The DC / DC 11 is connected to a generator and a high-voltage battery having a voltage higher than that of the PbB 12, and reduces the voltage of the generator and the high-voltage battery and outputs them to the first system 110. The generator is, for example, an alternator for generating electric power by converting kinetic energy of a traveling vehicle into electricity. The high-voltage battery is, for example, a vehicle drive battery that can be installed on an electric vehicle or a hybrid vehicle.

[0029] Incidentally, in a case where the first power supply 10 is installed on a gasoline vehicle, an alternator (generator) can be 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 (to be described below).

[0030] The power supply control device 1 includes a second power supply 20, an inter-system switch 41, a battery switch 42, a controller 3, a first voltage sensor 51, and a second voltage sensor 52. The second power supply 20 is a backup power supply for a case where power supply of the first power supply 10 becomes impossible. The second power supply 20 includes a lithium ion battery (hereinafter, referred to as "LiB 21"). However, the battery for the second power supply 20 can be any secondary battery other than the LiB 21.

[0031] The inter-system switch 41 is a switch provided on the inter-system line 130, and is used to connect the first system 110 and the second system 120, so as to be able to connect and disconnect the first system 110 and the second system 120 to and from each other. The battery switch 42 is a switch that is able to connect and disconnect the second power supply 20 and the second system 120 to and from each other.

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

[0033] The controller 3 includes a microcomputer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and the like, and various circuits. However, the controller 3 can be configured with hardware such as an application specific integrated circuit (ASIC) and a field programmable gate array (FPGA).

[0034] The CPU executes a program stored in the ROM, using the RAM as a work area, whereby the controller 3 controls the operation of the power supply control device 1. The controller 3 detects a ground fault of 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. Specific examples of the ground fault detection method using the controller 3 will be described below.

[0035] If a ground fault of the first system 110 or the second system 120 is detected, the controller 3 notifies the autonomous driving control device 100 thereof. However, if a ground fault of the first system 110 or the second system 120 is detected, the controller 3 can notify the autonomous driving control device 100 that autonomous driving is not possible. Furthermore, when no ground fault of the first system 110 or the second system 120 is detected, the controller 3 can notify the autonomous driving control device 100 that autonomous driving is possible.

[0036] If a power supply fault such as a ground fault occurs in the first system 110, the controller 3 turns off the inter-system switch 41, and turns on the battery switch 42, so as to supply power from the second power supply 20 to the second load 103. Furthermore, if a power supply fault such as a ground fault occurs in the second system 120, the controller 3 turns off the inter-system switch 41, and turns off the battery switch 42, so as to supply power from the first power supply 10 to the first load 101 and the general-purpose load 102.

[0037] Therefore, even if any one of the systems has a ground fault during autonomous driving, the power control device 1 uses another system so that the autonomous driving control device 100 can drive the vehicle to a safe place for evacuation and stop the vehicle. Now, the operation of the power control device 1 will be described with reference to Figures 2 to 8 The operation of the power control device 1 will be described with reference to

[0038] 2. Normal operation of the power control device

[0039] In a normal time in which there is no ground fault in the first system 110 and the second system 120, the controller 3 keeps the inter-system switch 41 in the conductive state while keeping the battery switch 42 off, as shown in Figure 2 to supply power from the first power source 10 to the first load 101, the general-purpose load 102, and the second load 103.

[0040] 3. Operation of the power control device

[0041] Now, the operation of the power control device 1 will be described with reference to Figures 3 to 8 The operation of the power control device 1 will be described with reference to Figures 3 to 8 is an explanatory diagram showing an example of the operation of the power control device according to the embodiment. As shown in Figure 3 In the power control device 1, for example, in the case where a ground fault 200 occurs in the first system 110, the voltage of the first system 110 detected by the first voltage sensor 51 becomes equal to or lower than the ground fault threshold value due to overcurrent flowing to the ground fault point.

[0042] In addition, in the power control device 1, in the case where a ground fault 200 occurs in the second system 120, the voltage of the second system 120 detected by the second voltage sensor 52 becomes equal to or lower than the ground fault threshold value due to overcurrent flowing to the ground fault point.

[0043] Therefore, if at least one of the voltages detected by the first voltage sensor 51 and the second voltage sensor 52 becomes equal to or lower than the ground fault threshold value, the controller 3 detects a power abnormality, and turns off the inter-system switch 41 and turns on the battery switch 42. At this time, the controller 3 temporarily determines that any ground fault has occurred in the first system 110 or the second system 120.

[0044] Thereafter, if the voltage detected by the first voltage sensor 51 is equal to or lower than the ground fault threshold value for more than a predetermined time, and the voltage detected by the second voltage sensor 52 is restored to a voltage higher than the ground fault threshold value within the predetermined time, the controller 3 definitely determines that a ground fault 200 has occurred in the first system 110.

[0045] Then, the controller 3 supplies power from the second power source 20 to the second load 103 (as shown in Figure 4The controller 3 determines that any ground fault has occurred in the first system 110 or the second system 120, and notifies the autonomous driving control device 100 of the determination. As a result, the autonomous driving control device 100 is able to make the vehicle travel to a safe place for evacuation and stop there by operating the second load 103 with the electric power supplied from the second power supply 20.

[0046] Further, after temporarily determining that any 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 ground fault threshold value for a predetermined time, and the voltage detected by the first voltage sensor 51 is restored to a voltage higher than the ground fault threshold value within the predetermined time, the controller 3 definitely determines that a ground fault 201 has occurred in the second system 120.

[0047] Then, the controller 3 turns off the battery switch 42 to supply the electric power from the first power supply 10 to the first load 101 (as shown in FIG. 1), and notifies the autonomous driving control device 100 of the determination. As a result, the autonomous driving control device 100 is able to make the vehicle travel to a safe place for evacuation and stop there by operating the first load 101 with the electric power supplied from the first power supply 10. Figure 5

[0048] Further, in the power supply control device 1, the voltage detected by the first voltage sensor 51 can temporarily be equal to or lower than the ground fault threshold value in the case where there is no ground fault 200 or 201, and the first load 101 or the general load 102 enters an overload state. Further, in the power supply control device 1, if the second load 103 enters an overload state, the voltage detected by the second voltage sensor 52 can temporarily become equal to or lower than the ground fault threshold value.

[0049] In this case, as shown in FIG. 1, the power supply control device 1 continues to supply the electric power from the first power supply 10 to the first load 101 and the general load 102, and from the second power supply 20 to the second load 103. Figure 6

[0050] Therefore, after temporarily determining that any ground fault has occurred in the first system 110 or the second system 120, if the voltages defined by the first voltage sensor 51 and the second voltage sensor 52 are both restored to a voltage higher than the ground fault threshold value within a predetermined time, the controller 3 definitely determines that there is no abnormality in the power supply. After that, the controller 3 turns off the battery switch 42 and turns on the inter-system switch 41 again to return to the normal operation shown in FIG. 1. Figure 2

[0051] ​​​At this time, in the power supply control device 1, since the second power supply 20 has been supplying power to the second load 103 from when the inter-system switch 41 was turned off until it was definitely determined that there was any abnormality in the power supply, the voltage of the second power supply 20 can be lower than the voltage of the first power supply 10. In addition, depending on the operating state of the first load 101, the general load 102, and the second load 103, the voltage of the first power supply 10 can be lower than the voltage of the second power supply 20.

[0052] In the power supply control device 1, if the inter-system switch is turned on again when the potential difference between the first power supply 10 and the second power supply 20 is large, the inter-system switch 41 can be damaged. For this reason, in a case where the potential difference between the first power supply 10 and the second power supply 20 is equal to or greater than a predetermined threshold value before the inter-system switch 41 is turned on again, the controller 3 performs convergence control so that the potential difference becomes smaller than the threshold value.

[0053] However, during the convergence control, in a case where the power supply control device 1 keeps the battery switch 42 in the conducting state, the second power supply 20 discharges, whereby the amount of charge in the LiB 21 decreases. Therefore, if it is definitely determined that there is no abnormality in the power supply, the controller 3 stores the voltage of the second power supply 20, and then turns off the battery switch 42, as shown in Figure 7

[0054] Thereafter, when the potential difference between the first power supply 10 and the second power supply 20 is equal to or greater than a predetermined threshold value, the controller 3 performs convergence control so that the potential difference becomes smaller than the threshold value. For example, in a case where the voltage of the second power supply 20 immediately before the battery switch 42 is turned off is lower than the voltage of the first power supply 10, the controller 3 outputs an instruction to the DC / DC 11 to lower the voltage of the first power supply 10, thereby performing the convergence control.

[0055] However, when the voltage of the second power supply 20 immediately before the battery switch 42 is turned off is lower than the voltage of the PbB 12, for example, the controller 3 can perform the convergence control by requesting a higher-level control device (not shown in the figure) to operate the general load 102 so that the power of the PbB 12 is forced to be consumed.

[0056] In addition, when the voltage of the first power supply 10 is lower than the voltage of the second power supply 20 immediately before the battery switch 42 is turned off, the controller 3 performs the convergence control by outputting a command to the DC / DC 11 to raise the voltage of the first power supply 10.

[0057] ​As described above, if it is determined that there is no abnormality in the power supply, the controller 3 immediately turns off the battery switch 42. Therefore, when the voltage of the second power supply 20 is lower than the voltage of the first power supply 10, the voltage of the second power supply 20 can be suppressed from dropping to the minimum value. Therefore, the controller 3 can minimize the voltage difference between the first power supply 10 and the second power supply 20. As a result, the time required for the convergence control can be reduced.

[0058] Further, after determining that there is no abnormality in the power supply, the controller 3 keeps the battery switch 42 off while performing the convergence control. Therefore, when the inter-system switch 41 is turned on again, the reduction in the amount of charge in the second power supply 20 can be suppressed.

[0059] Thereafter, when the convergence control is completed, the controller 3 turns on the battery switch 42 again, and then turns on the inter-system switch 41 again, as Figure 8 indicated, so that the second power supply 20 is charged with the electric power of the first power supply 10. Alternatively, the controller 3 can turn on the battery switch 42 and the inter-system switch 41 at the same time again.

[0060] At this time, since the power supply control device 1 keeps the potential difference between the first power supply 10 and the second power supply 20 below the predetermined threshold value by the convergence control, the inter-system switch 41 is not damaged even if the inter-system switch 41 is turned on again.

[0061] Thereafter, when the charging of the second power supply 20 is completed, the controller 3 turns off the battery switch 42. As a result, after returning to the normal operation, the power supply control device 1 can prevent the second power supply 20 from being unnecessarily discharged. Further, since the automatic driving is not allowed unless the second power supply 20 is charged to the voltage required for the backup control, the discharge of the second power supply 20 is suppressed. Therefore, the opportunity for the automatic driving increases.

[0062] Thereafter, in the case where a power supply failure such as a ground fault occurs in the first system 110, the power supply control device 1 can start the backup control using the second power supply 20 that is fully charged. Therefore, the evacuation running distance can be extended.

[0063] 4. Process performed by controller of power supply control device

[0064] Now, an example of a process performed by the controller according to the embodiment will be described with reference to Figure 9 FIG. 8. Figure 9 is a flowchart illustrating an example of a process performed by the controller of the power supply control device according to the embodiment. The controller 3 according to the embodiment repeatedly performs the process illustrated in Figure 9 FIG. 8 during the normal operation.

[0065] Specifically, as Figure 9As shown, first, the controller 3 determines whether any power abnormality has been detected (step S101). If it is determined that no power abnormality has been detected (NO in step S101), the controller 3 ends the processing and restarts the processing from step S101.

[0066] Meanwhile, if it is determined that a power abnormality has been detected (YES in step S101), the controller 3 turns off the inter-system switch 41 (step S102) and turns on the battery switch 42 (step S103). Subsequently, the controller 3 determines whether any abnormality exists in the power supply (step S104).

[0067] If it is determined that any abnormality exists in the power supply (YES in step S104), the controller 3 determines whether the abnormality is an abnormality of the second system 120 (step S113). If it is determined that the abnormality is an abnormality of the second system 120 (YES in step S113), the controller 3 turns off the battery switch 42 (step S114), notifies the autonomous driving control device 100 of the same (step S115), ends the processing, and restarts the processing from step S101. As a result, the evacuation travel control is executed using the first system 110.

[0068] Meanwhile, if it is determined that the abnormality is not an abnormality of the second system 120 (NO in step S113), because the abnormality is an abnormality of the first system 110, the controller 3 notifies the autonomous driving control device 100 of the same (step S115), ends the processing, and restarts the processing from step S101. As a result, the evacuation travel control is executed using the second system 120.

[0069] Meanwhile, if it is determined that no abnormality exists in the power supply (NO in step S104), the controller 3 stores the voltage of the second power supply 20 (step S105) and turns off the battery switch 42 (step S106). Subsequently, the controller 3 determines whether the voltage difference between the first power supply 10 and the second power supply 20 is equal to or greater than a threshold value (step S107).

[0070] If it is determined that the voltage difference between the first power supply 10 and the second power supply 20 is less than the threshold value (NO in step S107), the controller 3 advances the processing to step S109. Meanwhile, if it is determined that the voltage difference between the first power supply 10 and the second power supply 20 is equal to or greater than the threshold value (YES in step S107), the controller 3 executes the convergence control until the corresponding voltage difference becomes less than the threshold value (step S108).

[0071] Thereafter, the controller 3 turns on the battery switch 42 (step S109) and turns on the inter-system switch 41 (step S110). Subsequently, the controller 3 determines whether the charging of the second power supply 20 has been completed (step S111).

[0072] If it is determined that the charging of the second power supply 20 is not completed ("No" in step Sll l), the controller 13 repeats the determination process of step Sll l until the charging of the second power supply 20 is completed. Then, if it is determined that the charging of the second power supply 20 has been completed ("Yes" in step Sll l), the controller 3 turns off the battery switch 42 (step Sll 2), ends the process, and restarts the process from step S101.

[0073] Various advantages and modifications will be readily apparent to those skilled in the art. Therefore, the application in its broader aspects is not limited to the specific details, representative devices, and illustrative examples shown and described above. Accordingly, various modifications can be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

Claims

1. A power supply control apparatus comprising: a first system configured to supply power of a first power supply to a first load; a second system configured to supply power of a second power supply to a second load; an inter-system switch configured to connect and disconnect the first system and the second system to and from each other; a battery switch configured to connect and disconnect the second power supply to and from the second system; and a controller configured to turn off the inter-system switch and turn on the battery switch in response to detecting an abnormality in at least one of the first power supply or the second power supply, and thereafter turn on the inter-system switch again and turn off the battery switch in response to determining that there is no abnormality in the first power supply or the second power supply, wherein, before turning on the inter-system switch again, in a case where a voltage difference between the first power supply and the second power supply is equal to or greater than a threshold value, the controller performs convergence control so that the voltage difference becomes less than the threshold value, and after determining that there is no abnormality in the first power supply or the second power supply, the controller keeps the battery switch off while performing the convergence control.

2. The power supply control apparatus according to claim 1, wherein when the convergence control is completed, the controller turns on the inter-system switch and the battery switch to perform charging of the second power supply, and when the charging of the second power supply is completed, the controller turns off the battery switch. a first system configured to supply power of a first power supply to a first load; 3. A power supply control method of a power supply control apparatus including: a second system configured to supply power of a second power supply to a second load; an inter-system switch configured to connect and disconnect the first system and the second system to and from each other; and a battery switch configured to connect and disconnect the second power supply to and from the second system, the power supply control method comprising: turning off the inter-system switch and turning on the battery switch in response to detecting an abnormality in at least one of the first power supply or the second power supply, and thereafter turning on the inter-system switch again and turning off the battery switch in response to determining that there is no abnormality in the first power supply or the second power supply; and in a case where a voltage difference between the first power supply and the second power supply is equal to or greater than a threshold value, before turning on the inter-system switch again, performing convergence control so that the voltage difference becomes less than the threshold value, and after determining that there is no abnormality in the first power supply or the second power supply, keeping the battery switch off while performing the convergence control. ​

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