Power supply control device and power supply control method

Abstract

To provide a power supply control device and a power supply control method capable of preventing unnecessary cutting-off of an intersystem switch even when temporary excess current is generated due to an overload.SOLUTION: The power supply control device comprises: a first system that supplies power of a first power source to a first load; a second system that suppliers power of a second power source to a second load; an intersystem switch; a first current sensor; and an abnormality detection unit. The abnormality detection unit determines, when a current value flowing between the systems detected by the first current sensor is higher than a first threshold value and a current value supplied to the first load detected by the second current sensor and a current value supplied to the second load detected by a third current sensor are lower than a second threshold value, a ground fault to cut off the intersystem switch system.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 includes 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. In the event of a ground fault 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 source to the first load and the second load. When an overcurrent equal to or greater than a ground fault threshold flows in the inter-system line connecting the first system and the second system, for example, the redundant power supply system determines that a ground fault has occurred in the first system or the second system and shuts off the inter-system switch.

[0005] The redundant power supply system performs backup control to supply power from the second power supply to the second load when a ground fault is confirmed in the first system, and to supply power from the first power supply to the first load when a ground fault is confirmed in the second system, and notifies the automatic driving control device of the same. When a ground fault occurs in the first or second system, the automatic driving control device performs fail-safe control to prohibit continuation of automatic driving and to cause the vehicle to evacuate and stop. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2017-61240 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, if, for example, the first load or the second load enters a temporary overload state and an overcurrent flows in the inter-system line, the redundant power supply system may erroneously determine that a ground fault has occurred and unnecessarily shut off the inter-system switch.

[0008] 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 prevent unnecessary shutoff of inter-system switches even if a temporary overcurrent occurs due to an overload. [Means for solving the problem]

[0009] A power supply control device according to an embodiment includes a first system, a second system, an inter-system switch, a first current sensor, and an abnormality detection 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 on an inter-system line connecting the first system and the second system. The first current sensor detects a current value flowing through the inter-system line. When the abnormality detection unit detects that a current value detected by the first current sensor is higher than a first threshold value and that current values ​​detected by a second current sensor detecting a current supplied to the first load and a third current sensor detecting a current supplied to the second load are lower than a second threshold value, the abnormality detection unit determines that a ground fault has occurred and shuts off the inter-system switch. Effect of the Invention

[0010] The power supply control device and the power supply control method according to the embodiment have an effect of preventing unnecessary shutoff of the inter-system switch even if a temporary overcurrent occurs due to an overload. [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 a determination condition to be determined by the abnormality detection unit 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 a flowchart showing an example of an abnormality detection process executed by the abnormality detection unit of the power supply control device according to the embodiment. [Figure 9] FIG. 9 is a flowchart illustrating an example of a ground fault occurrence system determination process executed by the abnormality detection 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 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.

[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] [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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] The power supply control device 1 includes a second power supply 20, an inter-system switch 41, an abnormality detection unit 3, and a first current sensor 51. 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.

[0021] 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 first current sensor 51 is provided on the inter-system line 130, detects a current value of a current flowing through the inter-system line 130, and outputs the detection result to the abnormality detection unit 3.

[0022] A second current sensor 52 is provided at a current input portion of the first load 101 in the first system 110. Moreover, a third current sensor 53 is provided at a current input portion of the second load 103 in the second system 120.

[0023] The second current sensor 52 detects the current value of the current supplied to the first load 101, and outputs the detection result to the abnormality detection unit 3. The third current sensor 53 detects the current value of the current supplied to the second load 103, and outputs the detection result to the abnormality detection unit 3.

[0024] The abnormality detection unit 3 includes a microcomputer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and various circuits. The abnormality detection unit 3 may be configured with hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0025] The abnormality detection 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 working area. The abnormality detection unit 3 detects ground faults in the first system 110 and the second system 120 based on detection results input from the first current sensor 51, the second current sensor 52, and the third current sensor 53. A specific example of a method for detecting a ground fault by the abnormality detection unit 3 will be described later.

[0026] When the abnormality detection 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 abnormality detection 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 abnormality detection 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.

[0027] When a power failure such as a ground fault occurs in one of the first system 110 and the second system 120, the abnormality detection unit 3 shuts off the inter-system switch 41 and supplies power to the load through the other system in which no power failure has occurred.

[0028] 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 have the automatic driving control device 100 drive the vehicle to a safe place and stop the vehicle. Next, the operation of the power supply control device 1 will be described with reference to Figs. 2 to 7. Figs. 2 to 4 and Figs. 6 to 7 are explanatory diagrams showing an example of the operation of the power supply control device according to the embodiment. Fig. 5 is an explanatory diagram showing the judgment conditions to be used by the abnormality detection unit according to the embodiment.

[0029] [2. Normal operation of the power supply control device] During normal operation when no ground fault has occurred in the first system 110 and the second system 120, the abnormality detection unit 3 turns on the inter-system switch 41 as shown in FIG. 2 to supply power from the first power source 10 to the first load 101, the general load 102, and the second load 103.

[0030] [3. Operation when power supply control device detects overcurrent] Next, an operation of the power supply control device 1 when detecting an overcurrent will be described with reference to Figures 3 and 4. As shown in Figure 3, in the power supply control device 1, a ground fault 201 may occur between the first power supply 10 and the second current sensor 52 during normal operation.

[0031] In the power supply control device 1, when a ground fault 201 occurs, an overcurrent flows from the first power supply 10 and the second power supply 20 toward the location where the ground fault 201 occurred. At this time, since an overcurrent flows in the inter-system line 130, the abnormality detection unit 3 is able to detect the occurrence of the ground fault 201 when the overcurrent is detected by the first current sensor 51. When the ground fault 201 occurs, the power supply control device 1 shuts off the inter-system switch 41.

[0032] 4, in the power supply control device 1, a ground fault 202 may occur between the second power supply 20 and the third current sensor 53 during normal operation. When the ground fault 202 occurs in the power supply control device 1, an overcurrent flows from the first power supply 10 and the second power supply 20 toward the location where the ground fault 202 occurred. At this time, since an overcurrent flows in the inter-system line 130, the abnormality detection unit 3 is able to detect the occurrence of the ground fault 202 when the first current sensor 51 detects the overcurrent. When the ground fault 202 occurs, the power supply control device 1 shuts off the inter-system switch 41.

[0033] However, in the power supply control device 1, for example, when the first load 101 or the second load 103 is in an overload state, an overcurrent may temporarily flow in the inter-system line 130. The overload state in this case is not a power supply failure.

[0034] For this reason, if the abnormality detection unit 3 determines the occurrence of a ground fault 201 based only on the detection result of the first current sensor 51, it may erroneously determine that an overcurrent due to an overload condition is an overcurrent due to a ground fault 201, and unnecessarily shut off the inter-system switch 41, thereby terminating automatic operation even if there is no power supply failure.

[0035] Therefore, the abnormality detection unit 3 uses the detection results of the second current sensor 52 and the third current sensor 53 in addition to the detection result of the first current sensor 51 to accurately determine the occurrence of ground faults 201, 202. When the ground faults 201, 202 occur, the first current sensor 51 detects an overcurrent, but the second current sensor 52 and the third current sensor 53 do not detect an overcurrent, and instead the detected current decreases.

[0036] In contrast, for example, when the first load 101 is in an overload state, an overcurrent is detected by both the first current sensor 51 and the second current sensor 52, but an overcurrent is not detected by the third current sensor 53. Also, for example, when the second load 103 is in an overload state, an overcurrent is detected by both the first current sensor 51 and the third current sensor 53, but an overcurrent is not detected by the second current sensor 52.

[0037] Therefore, the abnormality detection unit 3 judges the ground fault 201 in the first system 110, the ground fault 202 in the second system 120, the overload state of the first load 101, and the overload state of the second load 103 according to the judgment conditions shown in Fig. 5. The first threshold value shown in Fig. 5 is set to be higher than the current value flowing through the inter-system line 130 during normal operation, for example.

[0038] The second threshold value is set to be lower than the value of the current flowing through the inter-system line 130 during normal operation. For example, the second threshold value is set to be equal to or lower than the value of the current flowing when the minimum power required for the first load 101 and the second load 103 to operate is supplied.

[0039] As shown in FIG. 5, when the abnormality detection unit 3 detects that the current value detected by the first current sensor 51 is higher than the first threshold value and the current values ​​detected by the second current sensor 52 and the third current sensor 53 are lower than the second threshold value, it determines that a ground fault 202 has occurred in the first system 110 or the second system 120, and shuts off the inter-system switch 41.

[0040] At this time, based on the detection result of the first current sensor 51, if the direction of the overcurrent flowing through the inter-system line 130 is from the second system 120 to the first system 110, the abnormality detection unit 3 determines that there is a ground fault 201 in the first system 110.

[0041] When the abnormality detection unit 3 determines that a ground fault 201 has occurred in the first system 110, it shuts off the inter-system switch 41 as shown in Fig. 6, and notifies the automatic driving control device 100 of that fact. As a result, the automatic driving control device 100 operates the second load 103 with power supplied from the second power source 20, and causes the vehicle to evacuate to a safe place and stop.

[0042] In addition, based on the detection result of the first current sensor 51, if the direction of the overcurrent flowing through the inter-system line 130 is from the first system 110 to the second system 120, the abnormality detection unit 3 determines that there is a ground fault 202 in the second system 120.

[0043] When the abnormality detection unit 3 determines that a ground fault 202 has occurred in the second system 120, it shuts off the inter-system switch 41 as shown in Fig. 7 and notifies the automatic driving control device 100 of that fact. As a result, the automatic driving control device 100 operates the first load 101 using power supplied from the first power source 10, and causes the vehicle to retreat to a safe place and stop.

[0044] Furthermore, as shown in FIG. 5 (first load overload), if the current values ​​detected by the first current sensor 51 and the second current sensor 52 are higher than the first threshold value and the current value detected by the third current sensor 53 is lower than the second threshold value, the abnormality detection unit 3 determines that the first load 101 is in an overload state and does not turn off the inter-system switch 41, causing it to maintain a conductive state.

[0045] Furthermore, as shown in FIG. 5 (second load overload), if the current values ​​detected by the first current sensor 51 and the third current sensor 53 are higher than the first threshold value and the current value detected by the second current sensor 52 is lower than the second threshold value, the abnormality detection unit 3 determines that the second load 103 is in an overload state and does not turn off the inter-system switch 41, causing it to maintain the conductive state.

[0046] As a result, the abnormality detection unit 3 can reliably shut off the inter-system switch 41 when an overcurrent occurs due to ground faults 201, 202, and can prevent unnecessary shutoff of the inter-system switch 41 when an overcurrent occurs due to an overload condition.

[0047] [4. Anomaly detection process executed by the anomaly determination unit] Next, an example of an abnormality determination process executed by the abnormality detection unit according to the embodiment will be explained with reference to Fig. 8. Fig. 8 is a flowchart showing an example of an abnormality detection process executed by the abnormality detection unit of the power supply control device according to the embodiment. The abnormality detection unit 3 according to the embodiment repeatedly executes the process shown in Fig. 9 during normal operation.

[0048] 8, the abnormality detection unit 3 first determines whether the current value of the first current sensor 51 is higher than a first threshold value (step S101). When the abnormality detection unit 3 determines that the current value of the first current sensor 51 is lower than the first threshold value (step S101, No), it determines that there is no abnormality (step S107), ends the process, and restarts the process from step S101.

[0049] In addition, if the abnormality detection unit 3 determines that the current value of the first current sensor 51 is higher than the first threshold value (step S101, Yes), it determines whether the current values ​​of the second current sensor 52 and the third current sensor 53 are lower than the second threshold value (step S102).

[0050] If the abnormality detection unit 3 determines that the current value of the second current sensor 52 or the third current sensor 53 is higher than the second threshold value (step S102, No), it determines that there is no abnormality (step S107), terminates the processing, and restarts the processing from step S101.

[0051] At this time, if the current value of the second current sensor 52 is higher than the first threshold value and the current value of the third current sensor 53 is lower than the second threshold value, the first load 101 is in an overload state, and if the current value of the second current sensor 52 is lower than the second threshold value and the current value of the third current sensor 53 is higher than the first threshold value, the second load 103 is in an overload state (see FIG. 5). However, since neither state is a ground fault 201, 202, the abnormality detection unit 3 determines that there is no abnormality, ends the process, and restarts the process from step S101.

[0052] In addition, if the abnormality detection unit 3 determines that the current values ​​of the second current sensor 52 and the third current sensor 53 are lower than the second threshold value (step S102, Yes), it determines that a ground fault has occurred in the first system 110 or the second system 120 (step S103).

[0053] Next, the abnormality detection unit 3 turns off the inter-system switch 41 (step S104) and executes a ground fault occurrence system determination process (step S105). An example of the ground fault occurrence system determination process will be described later with reference to Fig. 9. Thereafter, the abnormality detection unit 3 notifies the automatic driving control device 100 of the determination result of the ground fault occurrence system determination process (step S106) and ends the process.

[0054] [5. Earth fault occurrence system determination process executed by the anomaly determination unit] Next, an example of a ground fault occurrence system determination process executed by the abnormality detection unit according to the embodiment will be explained with reference to Fig. 9. Fig. 9 is a flowchart showing an example of a ground fault occurrence system determination process executed by the abnormality detection unit of the power supply control device according to the embodiment.

[0055] As shown in FIG. 9, when the abnormality detection unit 3 starts the process of determining the system in which a ground fault has occurred, it determines whether the direction of the overcurrent flowing through the inter-system line 130 is from the second system 120 to the first system 110 (step S201).

[0056] If the abnormality detection unit 3 determines that the direction of the overcurrent flowing through the inter-system line 130 is from the second system 120 to the first system 110 (step S201, Yes), it determines that it is a ground fault 201 in the first system 110 (step S202), terminates the ground fault occurrence system determination process, and proceeds to step S106 shown in Figure 8.

[0057] Furthermore, if the abnormality detection unit 3 determines that the direction of the overcurrent flowing through the inter-system line 130 is not from the second system 120 to the first system 110, that is, the direction is from the first system 110 to the second system 120 (step S201, No), it determines that there is a ground fault 202 in the second system 120 (step S203), terminates the ground fault occurrence system determination process, and proceeds to step S106 shown in Figure 8.

[0058] In the above embodiment, the power supply control device 1 is described as including the second current sensor 52 and the third current sensor 53, but this is merely an example. The second current sensor 52 may be provided inside the first load 101, for example. Similarly, the third current sensor 53 may be provided inside the second load 103.

[0059] In addition, when multiple first loads 101 are connected to the first system 110, the second current sensor 52 may be provided in each first load 101, or at the junction of wiring that supplies power to each first load 101.

[0060] Similarly, when multiple second loads 103 are connected to the second system 120, the third current sensor 53 may be provided in each second load 103, or at the junction of wiring supplying power to each second load 103.

[0061] In the above-described embodiment, the system in which a ground fault has occurred is determined based on the direction of the current flowing through the inter-system switch 41, but a voltage sensor (not shown) may be provided separately in each of the first system 110 and the second system 120, and the system in which a ground fault has occurred may be determined based on the voltage of each voltage sensor. In this case, the system in which the detected voltage of the voltage sensor is lower than the threshold value for determining a ground fault is determined to be the system in which a ground fault has occurred.

[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. Anomaly detection section 41 Intersystem switch 51 First current sensor 52 Second current sensor 53 Third current 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 provided on an inter-system line connecting the first system and the second system; a first current sensor for detecting a value of a current flowing in the inter-system line; an abnormality detection unit that, when detecting that a current value detected by the first current sensor is higher than a first threshold value and that current values ​​detected by a second current sensor that detects a current supplied to the first load and a third current sensor that detects a current supplied to the second load are lower than a second threshold value, determines that a ground fault has occurred and shuts off the inter-system switch; A power supply control device comprising:

2. The abnormality detection unit When it is detected that the current values ​​detected by the first current sensor and the second current sensor are higher than the first threshold value and the current value detected by the third current sensor is lower than the second threshold value, it is determined that the first load is an overload.

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

3. The abnormality detection unit When it is detected that the current values ​​detected by the first current sensor and the third current sensor are higher than the first threshold value and the current value detected by the second current sensor is lower than the second threshold value, it is determined that the second load is an overload.

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

4. a first system that supplies power from a first power source to a first load; a second system that supplies power from a second power source to a second load; an inter-system switch provided on an inter-system line connecting the first system and the second system; a first current sensor for detecting a value of a current flowing through the inter-system line; An abnormality detection unit of a power supply control device comprising: When it is detected that the current value detected by the first current sensor is higher than a first threshold value and the current values ​​detected by the second current sensor detecting the current supplied to the first load and the third current sensor detecting the current supplied to the second load are lower than a second threshold value, it is determined that a ground fault has occurred and the inter-system switch is shut off. A power supply control method comprising:

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