Power supply control device, power supply control method, and power supply control program

Abstract

To provide a power supply control device, a power supply control method, and a power supply control program, capable of reducing an error determination of a ground fault.SOLUTION: A power supply control device according to the present specification comprises a controller. The controller controls a connection part that can connect and disconnect a first system that supplies a power from a first power supply to a first load and a second system that supplies a power from a second power supply to a second load. The controller performs a first determination processing for determining that a parameter for detecting a first or second system ground fault is a ground fault in the case where a state where the parameter exceeds a first threshold value is continued for a first time threshold value or more and a second determination processing for determining that the parameter for detecting a first or second system ground fault is a ground fault in the case where a state where the parameter exceeds a second threshold value as a threshold value that exceeds the first threshold value is continued for a second time threshold value or more that is smaller than the first threshold value, and disconnects the connection part in the case where the ground fault is determined by the first or second determination processing.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power supply control device, a power supply control method, and a power supply control program. [Background technology]

[0002] Conventionally, there is known a redundant power supply system that includes a first system that supplies power from a main power supply to a load, and a second system that supplies power to the load from an auxiliary power supply when the main power supply fails. When this redundant power supply system detects a voltage drop corresponding to a ground fault, it provisionally determines that a ground fault has occurred, and disconnects the first system from the second system, thereby identifying the system in which the ground fault has occurred (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-152408 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned voltage drop includes not only voltage drops caused by ground faults, but also temporary voltage drops caused by overload, noise, etc. Therefore, even if the systems are disconnected due to a voltage drop, if the voltage drop is temporary, it is not a ground fault, and the systems will be reconnected after the voltage is restored. In other words, in the past, a temporary voltage drop was erroneously judged to be a ground fault, and there was a possibility that the systems would be unnecessarily disconnected.

[0005] The present application has been made in consideration of the above, and has an object to provide a power supply control device, a power supply control method, and a power supply control program that can reduce erroneous determination of a ground fault. [Means for solving the problem]

[0006] The power supply control device according to the present application includes a controller. The controller controls a connection unit capable of connecting and disconnecting a first system that supplies power from a first power source to a first load and a second system that supplies power from a second power source to a second load. The controller performs a first determination process to determine that a ground fault has occurred when a state in which a parameter for detecting a ground fault in the first system or the second system exceeds a first threshold continues for a first time threshold or more, and a second determination process to determine that a ground fault has occurred when a state in which a parameter for detecting a ground fault in the first system or the second system exceeds a second threshold, which is a threshold that exceeds the first threshold, continues for a second time threshold or more that is smaller than the first time threshold, and disconnects the connection unit when a ground fault has been determined in either the first determination process or the second determination process. Effect of the Invention

[0007] According to one aspect of the embodiment, an effect is achieved in that erroneous determination of a ground fault can be reduced. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is an explanatory diagram of the configuration and operation of a power supply control device according to an embodiment. [Diagram 2] FIG. 2 is an explanatory diagram of the configuration and operation of the power supply control device according to the embodiment. [Diagram 3] FIG. 3 is an explanatory diagram of the configuration and operation of the power supply control device according to the embodiment. [Figure 4] FIG. 4 is an explanatory diagram of the configuration and operation of the power supply control device according to the embodiment. [Figure 5A] FIG. 5A is a diagram for explaining the tentative determination process in the present disclosure. [Figure 5B] FIG. 5B is a diagram for explaining the tentative determination process in the present disclosure. [Figure 5C] FIG. 5C is a diagram for explaining the tentative determination process in the present disclosure. [Figure 6] FIG. 6 is a flowchart showing an example of the overall process executed by the controller. [Figure 7] FIG. 7 is a flowchart showing an example of a ground fault determination process executed by the controller. [Figure 8] FIG. 8 is a diagram illustrating an example of the configuration of a power supply control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of a power supply control device, a power supply control method, and a power supply control program 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 case where a vehicle equipped with a power supply control device according to the embodiment is an electric vehicle or a hybrid vehicle will be described.

[0010] The vehicle in which the power supply control device according to the embodiment is installed may be an engine vehicle that runs on an internal combustion engine. The power supply control device according to the embodiment is a device that is installed in a vehicle with an automatic driving function and supplies power to a load.

[0011] [Power supply control device configuration] The configuration and operation of a power supply control device 1 according to an embodiment will be described with reference to Fig. 1 to Fig. 4. Fig. 1 to Fig. 4 are explanatory diagrams of the configuration and operation of a power supply control device 1 according to an embodiment. As shown in Fig. 1, the power supply control device 1 according to an embodiment is connected to a main power supply 10, a first load 101, a general load 102, a second load 103, and an external device 100.

[0012] The power supply control device 1 includes a first system 110 and a second system 120. The first system 110 is a power supply system that supplies power from a main power supply 10 to a first load 101 and a general load 102. The second system 120 is a power supply system that supplies power from a backup power supply 20 (described later) to a second load 103.

[0013] The first load 101 includes a load for autonomous driving. The first load 101 includes, for example, a steering motor, an electric brake device, an in-vehicle camera, etc. that operate during autonomous driving. The general load 102 includes a display, an air conditioner, an audio device, a video device, various lights, etc.

[0014] The second load 103 has some of the functions for automatic driving that the first load 101 has. The second load 103 includes, for example, a steering motor, an electric brake device, and a radar, which are minimum devices required for FOP (Fail Operation, evacuation drive control). The first load 101, the general load 102, and the second load 103 operate with power supplied from the power supply control device 1.

[0015] The external device 100 is a device that controls the automatic driving of a vehicle by operating a first load 101 and a second load 103. When a power supply failure such as a ground fault occurs in the first system 110 during automatic driving of the vehicle, the external device 100 can implement FOP by the second load 103. Furthermore, when a power supply failure such as a ground fault occurs in the second system 120, the external device 100 can implement FOP by the first load 101.

[0016] Specifically, when a power failure occurs during automatic driving, the external device 100 performs evacuation driving control of the vehicle, drives the vehicle to a safe place and stops the vehicle. When the external device 100 normally completes the evacuation driving, it transmits an evacuation driving completion notification indicating that to the power supply control device 1.

[0017] The main 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"). Note that the battery of the main power supply 10 may be any secondary battery other than the 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. The DC / DC 11 steps down the voltage of the generator and the high-voltage battery and outputs it to the first system 110. The generator is an alternator that converts the kinetic energy of a traveling vehicle into electricity to generate power. The high-voltage battery is a battery for driving the vehicle that is installed in an electric vehicle or a hybrid vehicle.

[0019] When the main power supply 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 a first load 101 and a general load 102, supplies power to a second load 103, and charges the backup power supply 20 described below.

[0020] The power supply control device 1 includes a backup 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 backup power supply 20 is a backup power supply in the event that the main power supply 10 is unable to supply power. The backup power supply 20 includes a lithium ion battery (hereinafter referred to as "LiB21"). The battery of the backup power supply 20 may be any secondary battery other than the LiB21.

[0021] The inter-system switch 41 is provided on an inter-system line 130 that connects the first system 110 and the second system 120. The inter-system switch 41 is an example of a connection unit that can connect and disconnect the first system 110 and the second system 120.

[0022] In this embodiment, electrically connecting the first system 110 and the second system 120 by the inter-system switch 41 is referred to as making the inter-system switch 41 conductive or turning on the inter-system switch 41.

[0023] In the present embodiment, the cutting of the electrical connection between the first system 110 and the second system 120 by the inter-system switch 41 is referred to as interrupting the inter-system switch 41 or turning off the inter-system switch 41.

[0024] The inter-system switch 41 may be a DC / DC converter. In this case, the DC / DC converter is controlled by the controller 3. The DC / DC converter electrically connects the first system 110 and the second system 120 by starting operation, and disconnects the electrical connection between the first system 110 and the second system 120 by stopping operation.

[0025] The battery switch 42 is a switch that connects the backup power supply 20 to the second system 120. In the embodiment, electrically connecting the backup power supply 20 and the second system 120 by the battery switch 42 is referred to as making the battery switch 42 conductive or turning on the battery switch 42.

[0026] In addition, in this embodiment, cutting the electrical connection between the backup power supply 20 and the second system 120 by the battery switch 42 is referred to as interrupting the battery switch 42 or turning off the battery switch 42.

[0027] The first voltage sensor 51 is provided in the first system 110. The first voltage sensor 51 detects the voltage of the first system 110 and outputs the detection result to the controller 3. The second voltage sensor 52 is provided in the second system 120. The second voltage sensor 52 detects the voltage of the second system 120 and outputs the detection result to the controller 3.

[0028] The controller 3 includes a microcomputer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), etc., and various other circuits. The controller 3 may be configured with hardware such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA).

[0029] The controller 3 controls the operation of the power supply control device 1 by the CPU executing a program stored in the ROM using the RAM as a working area. The controller 3 controls the system switch 41 and the battery switch .

[0030] Furthermore, the controller 3 obtains a state value indicating the charging state of the backup power supply 20 from the backup power supply 20 via a state monitoring line 22. The state value indicating the charging state of the backup power supply 20 is, for example, a SOC (State Of Charge) of the LiB 21.

[0031] The LiB 21 is in a state where the remaining charge is maximum when the SOC is 100%. The LiB 21 is in a state where the remaining charge is zero when the SOC is 0%. The controller 3 acquires, for example, the SOC of the LiB 21 as a state value indicating the charging state of the backup power source 20. The controller 3 monitors the remaining charge of the backup power source 20 based on the SOC of the LiB 21.

[0032] Furthermore, the controller 3 detects a failure of the main power supply 10 or the backup power supply 20 based on the detection results input from the first voltage sensor 51 and the second voltage sensor 52. For example, the controller 3 detects a failure of the first system 110 or the second system 120. A failure of the main power supply 10 includes a ground fault in the first system 110 and a disconnection in the first system 110. A failure of the backup power supply 20 includes a ground fault in the second system 120. When the controller 3 detects a failure of the first system 110 or the second system 120, it notifies the external device 100 of that fact.

[0033] Specifically, when the controller 3 detects a failure of the main power source 10 or the backup power source 20, it outputs an automatic operation prohibition signal indicating that automatic operation is not possible to the external device 100. Moreover, when the controller 3 does not detect a failure of the main power source 10 or the backup power source 20, it outputs an automatic operation permission signal indicating that automatic operation is possible to the external device 100.

[0034] Furthermore, when the controller 3 detects a failure of the main power supply 10 or the backup power supply 20, it stores diagnostic information indicating the failure in the non-volatile memory. Then, at the next startup, if the diagnostic information is stored in the non-volatile memory, the controller 3 prohibits the external device 100 from performing automatic operation.

[0035] Specifically, the controller 3 prohibits the external device 100 from performing automatic driving by outputting an automatic driving prohibition signal to the external device 100, which indicates that automatic driving is not possible. This allows the power supply control device 1 to prevent the external device 100 from erroneously performing automatic driving even if the failure of the main power supply 10 or the backup power supply 20 has not been resolved at the next startup after the evacuation travel is completed.

[0036] [Normal operation of the power supply control device] The controller 3, during normal operation when neither the main power supply 10 nor the backup power supply 20 has a failure, controls the system switch 41 and the battery switch 42 as shown in Fig. 1. Specifically, the controller 3 turns off the battery switch 42 and turns on the system switch 41. This allows power to be supplied from the main power supply 10 to the first load 101, the general load 102, and the second load 103. During normal operation when neither the main power supply 10 nor the backup power supply 20 has a failure, the controller 3 outputs an automatic operation permission signal to the external device 100.

[0037] [Power supply control device operation when power supply fails] Next, the operation of the power supply control device 1 when a power failure occurs will be described with reference to Figures 2 to 4. The controller 3 detects the occurrence of a power failure by comparing a parameter related to a failure of the first system 110 or the second system 120 with a threshold value.

[0038] Here, a case will be described in which the parameter related to a failure of the main power supply 10 is the voltage of the first system 110, and the parameter related to a failure of the backup power supply 20 is the voltage of the second system 120. Hereinafter, the voltage of the first system 110 detected by the first voltage sensor 51 will be referred to as a first system voltage V1. Also, the voltage of the second system 120 detected by the second voltage sensor 52 will be referred to as a second system voltage V2.

[0039] The parameter related to the failure of the main power supply 10 may be the current flowing through the first system 110 or the current flowing through the second system 120. In this case, the power supply control device 1 includes a current sensor that detects the current flowing through the first system 110 and a current sensor that detects the current flowing through the second system 120. Then, the controller 3 detects the occurrence of a ground fault when the current flowing through the first system 110 or the current flowing through the second system 120 exceeds an overcurrent threshold.

[0040] 2, in the power supply control device 1, for example, when a ground fault 300 occurs in the first system 110 or when a ground fault 301 occurs in the second system 120, an overcurrent flows toward the ground fault point. As a result, the first system voltage V1 and the second system voltage V2 become equal to or lower than the ground fault threshold value.

[0041] When the first system voltage V1 or the second system voltage V2 becomes less than the ground fault threshold, the controller 3 provisionally determines that a ground fault 300 or a ground fault 301 has occurred in the first system 110 or the second system 120. After that, the controller 3 outputs an automatic driving prohibition signal to the external device 100. Note that the provisional determination process performed by the controller 3 is performed using a plurality of ground fault thresholds, and details of this point will be described later with reference to Figs. 5A to 5C.

[0042] Then, when the controller 3 provisionally determines that a ground fault 300 or 301 has occurred, it turns off the inter-system switch 41 and turns on the battery switch 42. This disconnects the first system 110 and the second system 120, so that power is supplied from the main power source 10 to the first system 110 and power is supplied from the backup power source 20 to the second system 120. Hereinafter, the shutoff of the inter-system switch 41 based on the result of the provisional determination is also referred to as pre-shutoff.

[0043] If, after the pre-shutdown, the first system voltage V1 continues to be less than the ground fault threshold for a predetermined period or more, and the second system voltage V2 continues to be greater than or equal to the normal threshold which is greater than the ground fault threshold for a predetermined period or more, the controller 3 determines that the second system 120 is normal and that the ground fault 300 has occurred in the first system 110. The predetermined period here is, for example, 100 ms. Note that the predetermined period is not limited to 100 ms. The normal threshold is a value higher than the ground fault threshold.

[0044] When the controller 3 determines that a ground fault 300 has occurred in the first system 110, it performs fail-safe control to supply power from the backup power source 20 to the second load 103, as shown in Fig. 3, and notifies the external device 100 of the result. This enables the external device 100 to operate the second load 103 using power supplied from the backup power source 20, and to evacuate the vehicle to a safe place and stop the vehicle. The fail-safe control may also include shutting off the inter-system switch 41 and turning on the battery switch 42 based on a provisional determination, and notifying the external device 100 of the result of the final determination.

[0045] In addition, after the pre-shutdown, if the first system voltage V1 recovers to be equal to or greater than the normal threshold for a predetermined period of time or more and the second system voltage V2 remains below the ground fault threshold for a predetermined period of time or more, the controller 3 makes a final determination that the first system 110 is normal and that a ground fault 301 has occurred in the second system 120.

[0046] When the controller 3 determines that a ground fault 301 has occurred in the second system 120, as shown in Fig. 4, it performs fail-safe control by turning off the battery switch 42 and supplying power from the main power supply 10 to the first load 101 and the general load 102. Then, the controller 3 notifies the external device 100 of this fact. As a result, the external device 100 can operate the first load 101 using power supplied from the main power supply 10, and can evacuate the vehicle to a safe place and stop it.

[0047] In the above description, a case has been described where a ground fault occurs in the first system 110 or the second system 120. However, the first system voltage V1 and the second system voltage V2 may temporarily drop in voltage value due to an overload, noise, or the like other than a ground fault.

[0048] Furthermore, since the controller 3 can determine a ground fault with high accuracy in the provisional determination process described below, when identifying the ground fault system in the main determination after the provisional determination, the time required to determine whether the voltage of each system returns to above the ground fault threshold value may be shortened. In other words, the controller 3 may immediately identify, in the main determination, a system in which the voltage is below the ground fault threshold value as a system in which a ground fault has occurred.

[0049] In the conventional provisional judgment process, even if the voltage value temporarily drops below the threshold due to overload, noise, or the like, the system switch 41 is cut off to identify the system in which the voltage abnormality occurs. In this case, the voltages of both the first system 110 and the second system 120 return to normal values, so the system switch 41 is reconnected and normal control is restored. That is, in the conventional provisional judgment process, a temporary voltage drop is erroneously provisionally judged to be a ground fault, and the systems are unnecessarily cut off. As a result, there was a risk that the driver would not be able to use the automatic driving function for a certain period of time until normal control was restored.

[0050] Therefore, in the present disclosure, a plurality of thresholds are set in the provisional determination process to reduce erroneous determination of a ground fault in the provisional determination process.Figures 5A to 5C are diagrams for explaining the provisional determination process in the present disclosure.

[0051] As shown in FIGS. 5A to 5C, in the present disclosure, a tentative judgment process is performed using three ground fault thresholds (first threshold TH1 to third threshold TH3). The first threshold TH1 is a threshold with the highest voltage value. The second threshold TH2 is a threshold with a lower voltage value than the first threshold TH1. The third threshold TH3 is a threshold with a lower voltage value than the second threshold TH2. In the following, the expression "exceeding the threshold" refers to "a state in which the voltage value has dropped below the threshold" when the parameter for detecting a ground fault is voltage, and refers to "a state in which the current value has increased to or above the threshold" when the parameter is current. In the following, a case in which the parameter for detecting a ground fault is voltage will be described as an example.

[0052] The controller 3 executes a first determination process using a first threshold value TH1, a second determination process using a second threshold value TH2, and a third determination process using a third threshold value TH3 in parallel. The first determination process is a process for provisionally determining that a ground fault has occurred when the voltage value of the first system 110 or the second system 120 exceeds the first threshold value TH1 for a first time threshold value or more. The second determination process is a process for provisionally determining that a ground fault has occurred when the voltage value of the first system 110 or the second system 120 exceeds the second threshold value TH2 for a second time threshold value or more that is shorter than the first time threshold value. The third determination process is a process for provisionally determining that a ground fault has occurred immediately when the voltage value of the first system 110 or the second system 120 exceeds the third threshold value TH3.

[0053] 5A to 5C show voltage drops by different patterns, and the tentative determination process for each pattern will be described.

[0054] First, Fig. 5A shows a pattern in which the voltage value of the first system 110 or the second system 120 drops below the first threshold value TH1 and is equal to or greater than the second threshold value TH2. Pattern A on the left side of Fig. 5A shows a case in which the voltage value returns to the first threshold value TH1 or greater, and pattern B on the right side shows a pattern in which the voltage value repeatedly rises and falls while being less than the first threshold value TH1.

[0055] In the case of FIG. 5A, the controller 3 performs only the first determination process, and does not perform the second and third determination processes, because the voltage value is less than the first threshold TH1 and is equal to or greater than the second threshold TH2. Specifically, in the case of pattern A of FIG. 5A, the controller 3 provisionally determines that there is no ground fault as a processing result of the first determination process, because the voltage value returns to the first threshold TH1 or greater within the first time threshold T1 after the voltage value becomes less than the first threshold TH1 in the first determination process. As a result, even if a temporary voltage drop occurs due to an overload, noise, or the like, it can be determined that there is no ground fault in the provisional determination process. As a result, the controller 3 can reduce unnecessary shutoff of the inter-system switch 41 due to a temporary voltage drop.

[0056] 5A, the controller 3 provisionally determines that there is a ground fault as the processing result of the first determination process because the state in which the voltage value is less than the first threshold value TH1 continues for the first time threshold value T1 or more. In this case, it provisionally determines that there is a ground fault when the first time threshold value T1 has elapsed. This makes it possible to detect with high accuracy, for example, a ground fault in which the voltage gradually decreases while repeatedly rising and falling.

[0057] Next, Fig. 5B shows a pattern in which the voltage value of the first system 110 or the second system 120 drops below the second threshold TH2 and is equal to or greater than the third threshold TH3. Pattern A on the left side of Fig. 5B shows a case in which the voltage value returns to the first threshold TH1 or greater. Pattern B in the center shows a case in which the voltage value stops rising when it is equal to or greater than the second threshold TH2 and less than the first threshold TH1. Pattern C on the right side shows a case in which the voltage value rises to the second threshold TH2 or greater, and then falls again to less than the second threshold TH2.

[0058] In the case of FIG. 5B, the decrease in the voltage value is less than the second threshold TH2 and is equal to or greater than the third threshold TH3, so the controller 3 performs the first determination process and the second determination process, but does not perform the third determination process.

[0059] Specifically, in the case of pattern A in Fig. 5B, the controller 3 starts time measurement in the first determination process at the timing when the voltage value becomes less than the first threshold value TH1. Then, the controller 3 ends the time measurement in the first determination process at the timing when the voltage value becomes equal to or greater than the first threshold value TH1 and outputs the determination result of the first determination process. That is, in the first determination process, the voltage value returns to equal to or greater than the first threshold value TH1 within the first time threshold value T1 after becoming less than the first threshold value TH1, so the controller 3 provisionally determines that there is no ground fault as the processing result of the first determination process.

[0060] 5B, the controller 3 starts time measurement in the second determination process when the voltage value becomes less than the second threshold value TH2. The controller 3 then ends time measurement in the second determination process when the voltage value becomes equal to or greater than the second threshold value TH2 and outputs a determination result of the second determination process. That is, the controller 3 provisionally determines that there is no ground fault as the processing result of the second determination process because the voltage value returns to equal to or greater than the second threshold value TH2 within the second time threshold value T2 after the voltage value becomes less than the second threshold value TH2.

[0061] 5B, the controller 3 determines that there is no ground fault in both the first and second determination processes, and therefore determines that there is no ground fault as the final determination result. This makes it possible to determine that there is no ground fault in the provisional determination process, even if a relatively large voltage drop occurs temporarily due to an overload, noise, or the like.

[0062] Next, in the case of pattern B in Figure 5B, since in the first judgment process, the state in which the voltage value is less than the first threshold value TH1 continues for longer than the first time threshold value T1, the controller 3 provisionally judges that a ground fault exists as a processing result of the first judgment process.

[0063] In addition, in pattern B of Figure 5B, in the second judgment process, the voltage value returns to above the second threshold TH2 within the second time threshold T2 after it becomes less than the second threshold TH2, so the controller 3 provisionally judges that there is no ground fault as the processing result of the second judgment process.

[0064] 5B, since the controller 3 determines that there is a ground fault in the first determination process out of the first and second determination processes, it determines that there is a ground fault as the final determination result. This makes it possible to detect with high accuracy, for example, a ground fault in which a relatively large voltage drop occurs initially, the voltage recovers once, and then the voltage gradually drops while repeatedly rising and falling.

[0065] Next, in the case of pattern C in Figure 5B, since in the first judgment process, the state in which the voltage value is less than the first threshold value TH1 continues for longer than the first time threshold value T1, the controller 3 provisionally judges that a ground fault exists as a processing result of the first judgment process.

[0066] In addition, in pattern C of Figure 5B, since the state in which the voltage value is less than the second threshold value TH2 continues for longer than the second time threshold value T2 in the second judgment process, the controller 3 provisionally judges that a ground fault exists as a processing result of the second judgment process.

[0067] For pattern C in Fig. 5B, since the controller 3 determines that a ground fault exists in both the first determination process and the second determination process, the controller 3 determines that a ground fault exists as the final determination result. Note that, in the case of pattern C in Fig. 5B, since the controller 3 provisionally determines that a ground fault exists in the second determination process, the controller 3 determines that a ground fault exists as the final determination result at the timing when the second time threshold T2 has elapsed. This makes it possible to detect a ground fault with high accuracy at an early stage, for example, in the case of a ground fault in which a relatively large voltage drop occurs in the early stage, the voltage recovers once, and then the voltage starts to drop substantially.

[0068] Next, Fig. 5C shows a pattern in which the drop in the voltage value of the first system 110 or the second system 120 is less than the third threshold value TH3. In the case of the pattern shown in Fig. 5C, since the voltage value is less than the third threshold value TH3, the controller 3 provisionally determines that there is a ground fault as the processing result of the third determination process, and determines that there is a ground fault as the final determination result without waiting for the processing results of the first determination process and the second determination process. This makes it possible to detect a ground fault early and with high accuracy.

[0069] The controller 3 determines whether or not a ground fault has occurred by at least a first determination process using the first threshold value TH1 and the first time threshold value T1, and a second determination process using the second threshold value TH2 and the first time threshold value T2. That is, the controller 3 performs the first determination process and the second determination process, and determines whether or not a ground fault has occurred if a ground fault has been determined first by either of the determination processes. This makes it possible to reduce erroneous determinations of a ground fault, compared to conventional ground fault determinations using a single ground fault threshold value.

[0070] However, since the first judgment process and the second judgment process require time measurement, there is a slight delay in detecting a ground fault when a ground fault actually occurs in the first system 110 or the second system 120. Therefore, the controller 3 performs the first judgment process, the second judgment process, and the third judgment process without time judgment in parallel, so that a ground fault can be detected early when a ground fault actually occurs. In other words, the controller 3 performs the first judgment process, the second judgment process, and the third judgment process, and when a ground fault is detected earliest in any of the judgment processes, the controller 3 confirms the ground fault, so that a ground fault can be detected early while reducing erroneous judgment of a ground fault.

[0071] If the controller 3 has already provisionally determined that there is a ground fault by the first determination process or the second determination process before the controller 3 provisionally determines that there is a ground fault by the third determination process, the controller 3 confirms that there is a ground fault without waiting for the determination result of the third determination process and turns off the inter-system switch 41. In other words, the controller 3 turns off the inter-system switch 41 at the timing when it provisionally determines that there is a ground fault earliest in any of the first determination process, the second determination process, and the third determination process. This allows the controller 3 to confirm the presence of a ground fault earlier, and therefore allows the controller 3 to perform fail-safe control earlier.

[0072] [Processing performed by the controller] Next, the processing executed by the controller 3 will be described with reference to Fig. 6 and Fig. 7. Fig. 6 is a flowchart showing an example of the overall processing executed by the controller 3. Fig. 7 is a flowchart showing an example of the ground fault determination processing executed by the controller 3. The processing shown in Fig. 6 and Fig. 7 is repeatedly executed from when the IG (ignition switch) of the vehicle is turned on until it is turned off.

[0073] As shown in FIG. 6, the controller 3 monitors the voltages of the first system 110 and the second system 120 using the first voltage sensor 51 and the second voltage sensor 52 (step S101).

[0074] Next, the controller 3 performs a ground fault determination process, which is a provisional determination process, based on the voltages of the first system 110 and the second system 120 (step S102). The ground fault determination process will be described later with reference to FIG.

[0075] Next, if it is determined in the ground fault determination process that there is a ground fault (step S103: Yes), the controller 3 turns off the inter-system switch 41 and connects the battery switch 42 (step S104). That is, the controller 3 disconnects the first system 110 and the second system 120, and connects the LiB 21 to the second system 120. Note that, if it is determined in the ground fault determination process that there is no ground fault (step S103: No), the controller 3 ends the process.

[0076] Next, the controller 3 identifies the system with the ground fault (step S105). The controller 3 turns off the inter-system switch 41 and turns on the battery switch 42, so that the voltage of the system with the ground fault continues to drop, but the voltage of the system without the ground fault recovers.

[0077] Therefore, the controller 3 compares the voltages of the first system 110 and the second system 120 with a threshold value for determining restoration (a value equal to or greater than the first threshold value TH1 for determining a ground fault). The controller 3 identifies the system whose voltage exceeds the threshold value for determining restoration first as a normal system, and identifies the other system as a system with a ground fault.

[0078] However, the method of identifying the ground-fault system is not limited to this. For example, the controller 3 may identify the ground-fault system from the change in the voltage of the first system 110 and the voltage of the second system 120 after the inter-system switch 41 is turned off and the battery switch 42 is turned on in step 104. Specifically, the controller 3 identifies a system whose voltage shows a tendency to recover as a normal system, and identifies a system whose voltage shows a tendency to decrease as a system with a ground fault.

[0079] Next, the controller 3 determines whether or not a ground fault has occurred in the first system 110 based on the identification result in step S105 (step S106). When the controller 3 determines that a ground fault has occurred in the first system 110 (step S106: Yes), the controller 3 continues to turn off the inter-system switch 41 and to turn on the battery switch 42 (step S107), and ends the process. That is, the controller 3 supplies power from the LiB 21 to the second load 103 via the second system 120.

[0080] On the other hand, in step S106, when the controller 3 determines that a ground fault has not occurred in the first system 110, that is, that a ground fault has occurred in the second system 120 (step S106: No), it continues to turn off the inter-system switch 41 and turns off the battery switch 42 (step S108), and ends the process. In other words, the controller 3 supplies power from the main power source 10 via the first system 110 to the first load 101 and the general load 102.

[0081] Next, the ground fault determination process will be described with reference to FIG.

[0082] As shown in FIG. 7, the controller 3 determines whether or not the voltage of the first system 110 or the second system 120 has dropped to less than the first threshold value TH1 (step S201).

[0083] When the voltage of the first system 110 or the second system 120 falls below the first threshold value TH1 (step S201: Yes), the controller 3 counts up the first timer (step S202) and determines whether the first timer value is equal to or greater than the first time threshold value T1 (step S203). On the other hand, when the voltage of the first system 110 or the second system 120 is equal to or greater than the first threshold value TH1 (step S201: No), the controller 3 clears the first timer value (step S204) and proceeds to step S205, which will be described later.

[0084] In step S203, if the first timer value is equal to or greater than the first time threshold T1 (step S203: Yes), the controller 3 determines that a ground fault has occurred (step S210). On the other hand, in step S203, if the first timer value is less than the first time threshold T1 (step S203: No), the controller 3 proceeds to step S205. Steps S201 to S204 and S210 correspond to a first determination process.

[0085] Next, in step S205, the controller 3 determines whether the voltage of the first system 110 or the second system 120 has dropped to less than the second threshold value TH2.

[0086] When the voltage of the first system 110 or the second system 120 falls below the second threshold value TH2 (step S205: Yes), the controller 3 counts up the second timer (step S206) and determines whether the second timer value is equal to or greater than the second time threshold value T2 (step S207). On the other hand, when the voltage of the first system 110 or the second system 120 is equal to or greater than the second threshold value TH2 (step S205: No), the controller 3 clears the second timer value (step S208) and proceeds to step S209, which will be described later.

[0087] In step S207, if the second timer value is equal to or greater than the second time threshold T2 (step S207: Yes), the controller 3 determines that a ground fault has occurred (step S210). On the other hand, in step S207, if the second timer value is less than the second time threshold T2 (step S207: No), the controller 3 proceeds to step S209. Steps S205 to S208 and S210 correspond to the second determination process.

[0088] Next, in step S209, the controller 3 determines whether the voltage of the first system 110 or the second system 120 has dropped below the third threshold TH3. If the voltage of the first system 110 or the second system 120 has dropped below the third threshold TH3 (step S209: Yes), the controller 3 determines that there is a ground fault (step S210). On the other hand, if the voltage of the first system 110 or the second system 120 is equal to or higher than the third threshold TH3 (step S209: No), the controller 3 ends the process. Steps S209 and S210 correspond to a third determination process.

[0089] Next, a configuration example of the power supply control device 1 will be described with reference to Fig. 8. Fig. 8 is a diagram showing a configuration example of the power supply control device 1. As shown in Fig. 8, the controller 3 of the power supply control device 1 includes a first determination unit 31, a second determination unit 32, and a third determination unit 33.

[0090] The first determination unit 31 is configured as software that performs a first determination process using the first threshold value TH1 and the first time threshold value T1. The first determination unit 31 as software performs the first determination process based on the voltage acquired from the first voltage sensor 51 or the second voltage sensor 52, and controls the system switch 41 and the battery switch 42 based on the process result.

[0091] The second determination unit 32 is configured as software that performs a second determination process using the second threshold value TH2 and the second time threshold value T2. The second determination unit 32 as software performs the second determination process based on the voltage acquired from the first voltage sensor 51 or the second voltage sensor 52, and controls the system switch 41 and the battery switch 42 based on the process result.

[0092] The third determination unit 33 is configured as software that performs a third determination process using a third threshold value TH3. The third determination unit 33 as software performs the third determination process based on the voltage acquired from the first voltage sensor 51 or the second voltage sensor 52, and controls the system switch 41 and the battery switch 42 based on the processing result. In this way, by configuring the first determination unit 31, the second determination unit 32, and the third determination unit 33 as software, the circuit configuration of the power supply control device 1 can be simplified.

[0093] The third determination unit 33 may be configured by hardware, not limited to software. The third determination unit 33 as hardware is a comparator that compares the voltage of the first voltage sensor 51 or the second voltage sensor 52 with the third threshold TH3. In this case, when the comparator detects that the voltage of the first voltage sensor 51 or the second voltage sensor 52 is equal to or lower than the third threshold TH3, the detection signal is latched by a latch circuit, and the output of the latch circuit cuts off the inter-system switch 41. The third determination unit 33 as a comparator can detect that the voltages of the first voltage sensor 51 and the second voltage sensor 52 are lower than the third threshold TH3 faster than when the third determination unit 33 is configured by software. The first determination unit 31 and the second determination unit 32 have a process of voltage comparison and a process of time measurement, and therefore, if these processes are configured by hardware, the circuit configuration becomes complicated. In this regard, since the third judgment unit 33 only performs voltage comparison processing and does not perform time measurement processing, by configuring the first judgment unit 31 and the second judgment unit 32 as software and the third judgment unit 33 as hardware, it is possible to ensure responsiveness in ground fault detection without complicating the circuit configuration.

[0094] As described above, the power supply control device 1 according to the embodiment includes the controller 3. The controller 3 controls a connection unit (inter-system switch 41) capable of connecting and disconnecting a first system 110 that supplies power from a first power source (main power source 10) to a first load 101 (and a general load 102) and a second system 120 that supplies power from a second power source (backup power source 20) to a second load 103. The controller 3 performs a first determination process for determining that a parameter (voltage or current) for detecting a ground fault in the first system 110 or the second system 120 has exceeded a first threshold value TH1 for a period of at least a first time threshold value T1, and a second determination process for determining that a parameter for detecting a ground fault in the first system 110 or the second system 120 has exceeded a second threshold value TH2, which is a threshold value that exceeds the first threshold value TH1, for a period of at least a second time threshold value T2 that is smaller than the first time threshold value T1, and disconnects the connection portion when a ground fault is determined in either the first determination process or the second determination process. This allows the power supply control device 1 to detect a ground fault with high accuracy while eliminating temporary voltage drops due to overload, noise, etc., and thus reduces erroneous determinations of a ground fault.

[0095] [Note] As an appendix, the features of the present invention are as follows: (1) a controller for controlling a connection unit capable of connecting and disconnecting a first system for supplying power from a first power source to a first load and a second system for supplying power from a second power source to a second load; The controller: a first determination process for determining that a ground fault has occurred when a state in which a parameter for detecting a ground fault in the first system or the second system exceeds a first threshold value continues for a first time threshold value or more; a second determination process for determining that a ground fault has occurred when a state in which a parameter for detecting a ground fault in the first system or the second system has exceeded a second threshold, which is a threshold that exceeds the first threshold, continues for a period equal to or longer than a second threshold time, which is smaller than the first threshold time, and When the ground fault is determined to occur in either the first determination process or the second determination process, the connection part is cut off. Power control device. (2) The controller: A third determination process is further performed to determine that a ground fault has occurred when the parameter exceeds a third threshold value that is a threshold value that exceeds the second threshold value; When the ground fault is determined to occur in any one of the first determination process, the second determination process, and the third determination process, the connection part is cut off. A power supply control device as described in (1). (3) The controller: The connection portion is disconnected at the timing when the ground fault is determined to occur earliest in any one of the first determination process, the second determination process, and the third determination process. A power supply control device as described in (2). (4) The controller: After disconnecting the connection, the system in which the ground fault occurs is identified based on the parameters. The power supply control device according to any one of (1) to (3). (5) The controller: The first judgment process, the second judgment process, and the third judgment process are performed by software. The power supply control device according to any one of (2) to (4). (6) The controller: The first and second determination processes are performed by software, and the third determination process is performed by hardware. The power supply control device according to any one of (2) to (5). (7) the hardware is a comparator; The controller: The parameter and the third threshold value are input to the comparator, and a determination result of the third determination process is output from the comparator. A power supply control device as described in (6). (8) A power supply control method executed by a power supply control device, controlling a connection unit capable of connecting and disconnecting a first system for supplying power from a first power source to a first load and a second system for supplying power from a second power source to a second load; a first determination process for determining that a ground fault has occurred when a state in which a parameter for detecting a ground fault in the first system or the second system exceeds a first threshold value continues for a first time threshold value or more; a second determination process for determining that a ground fault has occurred when a state in which a parameter for detecting a ground fault in the first system or the second system has exceeded a second threshold, which is a threshold that exceeds the first threshold, continues for a period equal to or longer than a second threshold time, which is smaller than the first threshold time, and When the ground fault is determined to occur in either the first determination process or the second determination process, the connection part is cut off. Power control method. (9) controlling a connection unit capable of connecting and disconnecting a first system for supplying power from a first power source to a first load and a second system for supplying power from a second power source to a second load; a first determination process for determining that a ground fault has occurred when a state in which a parameter for detecting a ground fault in the first system or the second system exceeds a first threshold value continues for a first time threshold value or more; a second determination process for determining that a ground fault has occurred when a state in which a parameter for detecting a ground fault in the first system or the second system has exceeded a second threshold, which is a threshold that exceeds the first threshold, continues for a period equal to or longer than a second threshold time, which is smaller than the first threshold time, and cutting off the connection portion when it is determined that a ground fault has occurred in either the first determination process or the second determination process. A power control program that causes a computer to run.

[0096] 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]

[0097] 1 Power supply control device 3. Controller 10 Main power supply 11 DC / DC 12 PbB 20 Backup Power 21 LiB 22 Condition monitoring line 31 1st Judgment Section 32 Second Judgment Section 33 Third Judgment Section 41 Intersystem switch 42 Battery switch 51 First voltage sensor 52 Second voltage sensor 100 External device 101 1st load 102 General load 103 2nd load 110 1st system 120 2nd system 130 Intersystem Line

Claims

1. a controller that controls a connection unit that can connect and disconnect a first system that supplies power from a first power source to a first load and a second system that supplies power from a second power source to a second load; The controller: a first determination process for determining that a ground fault has occurred when a state in which a parameter for detecting a ground fault in the first system or the second system exceeds a first threshold value continues for a first time threshold value or more; a second determination process for determining that a ground fault has occurred when a state in which a parameter for detecting a ground fault in the first system or the second system has exceeded a second threshold, which is a threshold that exceeds the first threshold, continues for a period equal to or longer than a second threshold time, which is smaller than the first threshold time; When the ground fault is determined to occur in either the first determination process or the second determination process, the connection part is cut off. Power control device.

2. The controller: A third determination process is further performed to determine that a ground fault has occurred when the parameter exceeds a third threshold value that is a threshold value that exceeds the second threshold value; When the ground fault is determined to occur in any one of the first determination process, the second determination process, and the third determination process, the connection part is cut off. The power supply control device according to claim 1 .

3. The controller: The connection portion is disconnected at the earliest timing at which the ground fault is determined to have occurred in any one of the first determination process, the second determination process, and the third determination process. The power supply control device according to claim 2.

4. The controller: After disconnecting the connection, the system in which the ground fault occurs is identified based on the parameters. The power supply control device according to claim 1 .

5. The controller: The first determination process, the second determination process, and the third determination process are performed by software. The power supply control device according to claim 2.

6. The controller: The first and second determination processes are performed by software, and the third determination process is performed by hardware. The power supply control device according to claim 2.

7. the hardware is a comparator; The controller: The parameter and the third threshold value are input to the comparator, and a determination result of the third determination process is output from the comparator. The power supply control device according to claim 6.

8. A power supply control method executed by a power supply control device, controlling a connection unit capable of connecting and disconnecting a first system for supplying power from a first power source to a first load and a second system for supplying power from a second power source to a second load; a first determination process for determining that a ground fault has occurred when a state in which a parameter for detecting a ground fault in the first system or the second system exceeds a first threshold value continues for a first time threshold value or more; a second determination process for determining that a ground fault has occurred when a state in which a parameter for detecting a ground fault in the first system or the second system has exceeded a second threshold, which is a threshold that exceeds the first threshold, continues for a period equal to or longer than a second threshold time, which is smaller than the first threshold time; When the ground fault is determined to occur in either the first determination process or the second determination process, the connection part is cut off. Power control method.

9. controlling a connection unit capable of connecting and disconnecting a first system for supplying power from a first power source to a first load and a second system for supplying power from a second power source to a second load; a first determination process for determining that a ground fault has occurred when a state in which a parameter for detecting a ground fault in the first system or the second system exceeds a first threshold value continues for a first time threshold value or more; a second determination process for determining that a ground fault has occurred when a state in which a parameter for detecting a ground fault in the first system or the second system has exceeded a second threshold, which is a threshold that exceeds the first threshold, continues for a period equal to or longer than a second threshold time, which is smaller than the first threshold time; cutting off the connection portion when it is determined that a ground fault has occurred in either the first determination process or the second determination process. A power control program that causes a computer to run.

Images