Power supply control device and power supply control method

Abstract

To provide a power source controller capable of suppressing a decrease in charge amount of a second power when an inter-system switch is reconnected, and a power source control method.SOLUTION: A power source controller includes a first system, a second system, an inter-system switch, a battery switch, and a control part. The first system supplies a first load with power of a first power source. The second system supplies a second load with power of a second power source. The inter-system switch can connect / disconnect the first system and the second system. The battery switch can connect / disconnect the second power source to / from the second system. The control part disconnects the inter-system switch when abnormality of the power source is detected, re-conducts the inter-system switch and disconnects the battery switch when it is determined that the power source has no abnormality after re-conduction of the battery switch, and performs convergence control so that a voltage difference between the systems is threshold or larger becomes below threshold when re-conduction of the inter-system switch is performed, during which the battery switch is disconnected.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 overloaded, the voltages of the first power supply and 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 be continued 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 the power supply system, the second power supply discharges during the period from when the inter-system switch is disconnected to when it is reconnected, and so the amount of charge in the second power supply decreases when the inter-system switch is reconnected.

[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 suppress a voltage drop in a second power supply when an inter-system switch is reconnected. [Means for solving the problem]

[0011] A power supply control device according to an embodiment includes a first system, a second system, an inter-system switch, a battery switch, and a control unit. The first system supplies power from a first power supply to a first load. The second system supplies power from a second power supply to a second load. The inter-system switch is capable of connecting and disconnecting the first system and the second system. The battery switch is capable of connecting and disconnecting the second power supply to the second system. When a power supply abnormality is detected, the control unit shuts off the inter-system switch, and when it is determined that there is no abnormality in the power supply after conducting the battery switch, it re-conducts the inter-system switch and shuts off the battery switch. When the control unit re-conducts the inter-system switch, if a voltage difference between the first power supply and the second power supply is equal to or greater than a threshold, it performs convergence control so that the voltage difference falls below the threshold, and after it is determined that there is no abnormality in the power supply, it shuts off the battery switch while performing the convergence control. Effect of the Invention

[0012] A power supply control device and a power supply control method according to an aspect of the embodiment provide an effect of suppressing a decrease in the charge amount of the second power supply when the inter-system switch is reconnected. [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 battery switch 42, a control unit 3, a first voltage sensor 51, and a second voltage sensor 52. 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.

[0023] The inter-system switch 41 is provided on the inter-system line 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 second power source 20 and the second system 120.

[0024] 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.

[0025] 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).

[0026] 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.

[0027] 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.

[0028] 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 battery switch 42, and supplies power from the second power source 20 to the second load 103. When a power failure such as a ground fault occurs in the second system 120, the 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.

[0029] 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.

[0030] [2. Normal operation of the power supply control device] Under normal circumstances when no ground fault has occurred in the first system 110 and the second system 120, the control unit 3 turns on the inter-system switch 41 while keeping the battery switch 42 off, 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.

[0031] [3. Operation of the power supply control device] Next, the 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. As shown in Fig. 3, in the power supply control device 1, for example, when a ground fault 200 occurs in the first system 110, an overcurrent flows toward the ground fault point, and 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.

[0032] Furthermore, in the power supply control device 1, when a ground fault 201 occurs in the second system 120, an overcurrent flows toward the ground fault point, and 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.

[0033] Therefore, 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, the control unit 3 detects an abnormality in the power supply, turns off the inter-system switch 41, and turns on the battery switch 42. 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] Thereafter, if the voltage detected by the first voltage sensor 51 remains below the ground fault threshold for a predetermined time or more even after a predetermined time has elapsed, 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 makes a definitive determination that a ground fault 200 has occurred in the first system 110.

[0035] 4, the control unit 3 supplies power from the second power source 20 to the second load 103 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 with the power supplied from the second power source 20, and can evacuate the vehicle to a safe place and stop the vehicle.

[0036] 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 even after a predetermined time has elapsed and the voltage detected by the first voltage sensor 51 returns to exceed the ground fault threshold within the predetermined time, the control unit 3 finally determines that a ground fault 201 has occurred in the second system 120.

[0037] 5, the control unit 3 turns off the battery switch 42, 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 can operate the first load 101 using the power supplied from the first power source 10, and evacuate the vehicle to a safe place and stop the vehicle.

[0038] 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.

[0039] In this case, as shown in FIG. 6, 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 continuously supplied from the second load 103 to the second load 103.

[0040] 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 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 finally determines 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-opens the inter-system switch 41.

[0041] At this time, in the power supply control device 1, since the second power supply 20 has supplied power to the second load 103 from the time the inter-system switch 41 is shut off until the power supply control device 1 determines that there is no abnormality in the power supply, the voltage of the second power supply 20 may be lower than the voltage of the first power supply 10. Also, depending on the operating states of the first load 101, the general load 102, and the second load 103, the voltage of the first power supply 10 may be lower than the voltage of the second power supply 20.

[0042] In the power supply control device 1, if the inter-system switch 41 is re-connected while the potential difference between the first power supply 10 and the second power supply 20 is large, there is a risk of damaging the inter-system switch 41. Therefore, when the inter-system switch 41 is re-connected, if the potential difference between the first power supply 10 and the second power supply 20 is equal to or greater than a predetermined threshold, the control unit 3 performs convergence control so that the potential difference falls below the threshold.

[0043] However, if the power supply control device 1 keeps the battery switch 42 conductive during convergence control, the second power supply 20 will discharge, reducing the amount of charge in the LiB 21. Therefore, as shown in Fig. 7, when the control unit 3 determines that there is no abnormality in the power supply, it stores the voltage of the second power supply 20 and then turns off the battery switch 42.

[0044] Thereafter, if the potential difference between the first power source 10 and the second power source 20 is equal to or greater than a predetermined threshold, the control unit 3 performs convergence control so that the potential difference falls below the threshold. For example, if the voltage of the second power source 20 immediately before turning off the battery switch 42 is lower than the voltage of the first power source 10, the control unit 3 performs convergence control by outputting a command to the DC / DC 11 to step down the voltage of the first power source 10.

[0045] In addition, when the voltage of the second power source 20 immediately before turning off the battery switch 42 is lower than the voltage of PbB12, the control unit 3 may perform convergence control, for example, by requesting a higher-level control device (not shown) to operate the general load 102 and forcibly consume the power of PbB12.

[0046] In addition, when the voltage of the first power source 10 is lower than the voltage of the second power source 20 immediately before the battery switch 42 is turned off, the control unit 3 outputs a command to the DC / DC 11 to boost the voltage of the first power source 10, thereby performing convergence control.

[0047] In this way, when the control unit 3 determines that there is no abnormality in the power supply, it immediately turns off the battery switch 42, so that it is possible to minimize a voltage drop in the second power supply 20 when the voltage of the second power supply 20 is lower than the voltage of the first power supply 10. Therefore, the control unit 3 can make the voltage difference between the first power supply 10 and the second power supply 20 as small as possible, thereby shortening the time required for convergence control.

[0048] In addition, after determining that there is no abnormality in the power supply, the control unit 3 cuts off the battery switch 42 while performing convergence control, thereby suppressing a decrease in the charge amount of the second power supply 20 when the system switch 41 is reconnected.

[0049] Thereafter, when the convergence control is completed, the control unit 3 restores conduction to the battery switch 42 and then the inter-system switch 41 as shown in Fig. 8, and charges the second power source 20 with the power of the first power source 10. Note that the control unit 3 may restore conduction to the battery switch 42 and the inter-system switch 41 at the same time.

[0050] At this time, the power supply control device 1 keeps the potential difference between the first power supply 10 and the second power supply 20 below a predetermined threshold value by convergence control, so that the inter-system switch 41 is not damaged even if it is made conductive again.

[0051] Thereafter, when charging of the second power source 20 is completed, the control unit 3 turns off the battery switch 42. This allows the power supply control device 1 to prevent unnecessary discharge of the second power source 20 after returning to normal operation. Furthermore, since automatic operation is not permitted if the second power source 20 is not charged to a voltage required for backup control, suppressing discharge of the second power source 20 increases the opportunities for automatic operation.

[0052] Furthermore, if a power supply failure such as a ground fault occurs in the first system 110, the power supply control device 1 can start backup control using the second power supply 20 in a fully charged state, thereby making it possible to extend the distance of evacuation travel.

[0053] [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.

[0054] 9, the control unit 3 first determines whether or not a power supply abnormality is detected (step S101). If the control unit 3 determines that a power supply abnormality is not detected (step S101, No), the control unit 3 ends the process and restarts the process from step S101.

[0055] If the control unit 3 determines (provisionally determines) that a power supply abnormality has been detected (step S101, Yes), it turns off the system switch 41 (step S102) and turns on the battery switch 42 (step S103). After that, the control unit 3 determines (mainly determines) whether or not there is an abnormality in the power supply (step S104).

[0056] When the control unit 3 determines that there is a main abnormality in the power supply (step S104, No), it determines whether there is an abnormality in the second system 120 (step S113). When the control unit 3 determines that there is an abnormality in the second system 120 (step S113, Yes), it turns off the battery switch 42 (step S114), notifies the automatic driving control device 100 of that fact (step S115), ends the process, and restarts the process from step S101. As a result, evacuation travel control is performed by the first system 110.

[0057] Furthermore, when the control unit 3 determines that the abnormality is not in the second system 120 (step S113, No), since the abnormality is in the first system 110, it notifies the user of that fact (step S115), ends the process, and restarts the process from step S101. As a result, the evacuation travel control by the second system 120 is performed.

[0058] If the control unit 3 determines that there is no abnormality in the power supply (Yes in step S104), it stores the voltage of the second power supply 20 (step S105) and turns off the battery switch 42 (step S106). After that, the control unit 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).

[0059] When the control unit 3 determines that the voltage difference between the first power source 10 and the second power source 20 is not equal to or greater than the threshold value (step S107, No), the control unit 3 proceeds to step S109. When the control unit 3 determines that the voltage difference between the first power source 10 and the second power source 20 is equal to or greater than the threshold value (step S107, Yes), the control unit 3 performs convergence control until the voltage difference falls below the threshold value (step S108).

[0060] Thereafter, the control unit 3 turns on the battery switch 42 (step S109), and turns on the system switch 41 (step S110). Next, the control unit 3 determines whether or not charging of the second power source 20 has been completed (step S111).

[0061] If the control unit 3 determines that charging of the second power source 20 is not complete (step S111, No), it repeats the determination process of step S111 until charging of the second power source 20 is complete. If the control unit 3 determines that charging of the second power source 20 is complete (step S111, Yes), it turns off the battery switch 42 (step S112), ends the process, and restarts the process 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 51 First voltage sensor 52 Second voltage sensor 100 Automatic driving control device 101 1st load 102 General load 103 2nd load 110 1st system 120 2nd system 130 Intersystem Line

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 capable of connecting and disconnecting the first system and the second system; a battery switch capable of connecting and disconnecting the second power source to the second system; a control unit that, when detecting an abnormality in a power supply, shuts off the inter-system switch and turns on the battery switch, and then, when determining that there is no abnormality in the power supply, re-turns on the inter-system switch and shuts off the battery switch; When the control unit re-connects the inter-system switch, if a voltage difference between the first power source and the second power source is equal to or greater than a threshold, the control unit performs convergence control so that the voltage difference falls below the threshold, and after determining that there is no abnormality in the power source, shuts off the battery switch while performing the convergence control. A power supply control device comprising:

2. The control unit is When the convergence control is completed, the system switch and the battery switch are turned on to charge the second power source, and when charging is completed, the battery switch is turned off.

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

3. 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 capable of connecting and disconnecting the first system and the second system; a battery switch capable of connecting and disconnecting the second power source to the second system; A control unit of a power supply control device comprising: when detecting an abnormality in a power supply, turning off the inter-system switch and turning on the battery switch, and then when determining that there is no abnormality in the power supply, turning on the inter-system switch again and turning off the battery switch; When the inter-system switch is re-connected, if a voltage difference between the first power source and the second power source is equal to or greater than a threshold, a convergence control is performed so that the voltage difference falls below the threshold, and after it is determined that there is no abnormality in the power source, the battery switch is shut off while the convergence control is being performed. A power supply control method comprising:

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