Power supply control device and power supply control program

Abstract

To provide a power supply control device and a power supply control program capable of avoiding an interruption of a power supply to a load due to a ground fault with high accuracy.SOLUTION: In a power supply control device according to an embodiment, a controller connects a first power supply switch, a second bypass switch, and a load switch and cuts off the second power supply switch and the first bypass switch when a vehicle is in a normal state during traveling. When a ground fault location is either the first power supply or the second power supply, the controller cuts off each power switch and each bypass switch on one power supply side, which is the ground fault location, and connects each power switch on the other power supply side and cuts off the other bypass switch.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] A conventional vehicle power supply system includes a first system that supplies power from a main power supply to a load, a second system that supplies power from a sub-power supply to the load, and an inter-system switch that connects the systems. In such a system, when a power supply failure occurs due to a ground fault, the inter-system switch is shut off to isolate the ground-faulted system, and power is supplied to the load from a normal power supply that has not failed. In addition, a technology is known for preventing reverse current flow in this type of system by configuring the inter-system switch with a pair of field effect transistors (FETs) whose body diodes have their cathodes reversed.

[0003] Furthermore, Patent Document 1 discloses a technique for preventing a sudden drop in the output voltage of a power supply during the period from the occurrence of a ground fault to the shutting off of the switch by providing an inductance section between the pair of FETs. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2017-192251 Summary of the Invention [Problem to be solved by the invention]

[0005] However, with conventional technology, if one power supply fails and the inter-system switch is shut off, and a ground fault occurs on the load side, the output voltage of the other power supply, which is normal, also drops, and there is a risk that sufficient power cannot be supplied to a normal load that is not affected by a ground fault.

[0006] The present invention has been made in view of the above, and has an object to provide a power supply control device and a power supply control program that can accurately prevent power supply to a load from being interrupted due to a ground fault. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, a power supply control device according to the present invention includes a first power switch, a second power switch, a first bypass switch, a second bypass switch, a load switch, and a controller. The first power switch is provided on a first power supply line between a first power supply and a load, and includes a pair of FETs whose body diode anodes are in opposite directions, and an inductor connected in series between the pair of FETs. The second power switch is provided on a second power supply line between a second power supply and the load, and includes a pair of FETs whose body diode anodes are in opposite directions, and an inductor connected in series between the pair of FETs. The first bypass switch is connected in parallel to the first power switch. The second bypass switch is connected in parallel to the second power switch. The load switch is provided on a load power supply line connected to the first power supply line and the second power supply line and supplying power to the load. The controller, during normal operation while the vehicle is running, connects the first power switch, the second bypass switch, and the load switch, and cuts off the second power switch and the first bypass switch. When the controller detects a ground fault, it identifies the location of the ground fault, and if the location of the ground fault is either the first power supply or the second power supply, it cuts off the power switch and bypass switch on the side of the power supply where the ground fault is located, and connects the power switch on the other power supply, and cuts off the other bypass switch. [Effects of the Invention]

[0008] According to the present invention, when the power switch on the power supply side with a ground fault is turned off, a voltage drop in the normal power supply is suppressed by the back electromotive force of the inductor of the power switch during the period from the occurrence of the ground fault until the power switch is turned off, thereby preventing the power supply to the load from being interrupted with high precision. Furthermore, even if a ground fault occurs on the load side after that, a voltage drop in the normal power supply is suppressed by the back electromotive force of the inductor of the power switch on the normal power supply, thereby preventing the power supply to the normal load without a ground fault from being interrupted with high precision. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is an explanatory diagram illustrating an example of the configuration of a power supply control system according to an embodiment. [Figure 2] FIG. 2 is a diagram showing the operation of the power supply control system in normal operation while the vehicle is running. [Figure 3] FIG. 3 is a diagram illustrating an example of the operation of the power supply control system when a ground fault occurs on the main power supply side. [Figure 4] FIG. 4 is a diagram illustrating an example of the operation of the power supply control system when a ground fault occurs on the main power supply side. [Figure 5] FIG. 5 is a diagram illustrating an example of the operation of the power supply control system when a ground fault occurs on the main power supply side. [Figure 6] FIG. 6 is a diagram illustrating an example of the operation of the power supply control system when a ground fault occurs on the sub-power supply side. [Figure 7] FIG. 7 is a diagram illustrating an example of the operation of the power supply control system when a ground fault occurs on the sub-power supply side. [Figure 8] FIG. 8 is a diagram illustrating an example of the operation of the power supply control system when a ground fault occurs on the sub-power supply side. [Figure 9] FIG. 9 is a diagram illustrating an example of the operation of the power supply control system when a ground fault occurs on the load side. [Figure 10] FIG. 10 is a diagram illustrating an example of the operation of the power supply control system when a ground fault occurs on the load side. [Figure 11] FIG. 11 is a flowchart showing the processing procedure for identifying the location of a ground fault in the power supply control device according to the embodiment. [Figure 12] FIG. 12 is a flowchart showing a processing procedure of the power supply control device according to the embodiment after a ground fault occurs in the main power supply. [Figure 13] FIG. 13 is a flowchart showing a processing procedure of the power supply control device according to the embodiment after a sub-power supply ground fault occurs. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A power supply control device and a power supply control program according to embodiments will be described in detail below with reference to the accompanying drawings. Note that the present invention is not limited to the following embodiments.

[0011] [Configuration example of power supply control system according to the embodiment] FIG. 1 is an explanatory diagram showing an example of the configuration of a power supply control system S according to an embodiment. As shown in FIG. 1, the power supply control system S includes a power supply control device 1, a main power supply 10, a sub-power supply 20, a first load 101, and a second load 102. In the power supply control system S, the main power supply 10, the sub-power supply 20, the first load 101, and the second load 102 are connected to the power supply control device 1. Here, a case will be described in which two loads are connected to the power supply control device 1, but the number of loads connected to the power supply control device 1 may be three or more. Furthermore, hereinafter, when there is no need to distinguish between the first load 101 and the second load 102, they may be collectively referred to as "loads."

[0012] The main power supply 10 is, for example, a main battery mounted on a vehicle. The main power supply 10 includes a main battery 10a and a DCDC 10b. The main battery 10a is, for example, a lead battery. The main battery 10a may be a secondary battery other than a lead battery. The DCDC 10b is a converter that steps down the voltage (output voltage) of the main battery 10a. The main power supply 10 is an example of a first power supply.

[0013] The sub-power source 20 is a backup power source that supplies power in place of the main power source 10 when the main power source 10 is unable to supply power. The sub-power source 20 includes a sub-battery 20a. The sub-battery 20a is, for example, a lithium ion battery. Note that the sub-battery 20a may also be a secondary battery other than a lithium ion battery. The sub-power source 20 is an example of a second power source.

[0014] In this embodiment, the voltage (output voltage) of the main power supply 10 is described as being slightly higher than the voltage (output voltage) of the sub-power supply 20 (for example, a voltage difference of about 0.5 to 1 V).

[0015] The first load 101 and the second load 102 include various electronic devices mounted on a vehicle, such as an engine control device, a steering control device, a brake control device, an audio device, a video display device, and various sensors.

[0016] The main power supply 10 is electrically connected to the power supply control device 1 via a main power supply line L1. The sub-power supply 20 is electrically connected to the power supply control device 1 via a sub-power supply line L2. The first load 101 and the second load 102 are electrically connected to the power supply control device 1 via a load power supply line L3. The main power supply line L1 and the sub-power supply line L2 are electrically connected to the load power supply line L3 inside the power supply control device 1. The main power supply line L1 and the sub-power supply line L2 are the first power supply line and the second power supply line.

[0017] The power supply control device 1 is a device that outputs (supplies) power input from a main power supply 10 or a sub-power supply 20 to a first load 101 and a second load 102. The power supply control device 1 includes a controller 2, a main power switch 31, a main bypass switch 32, a sub-power switch 41, a sub-bypass switch 42, a first load switch 51, a second load switch 52, and first to fourth sensors 61 to 64.

[0018] In the following, when there is no particular distinction between the main power switch 31 and the sub-power switch 41, they may be collectively referred to as the "power switch." In the following, when there is no particular distinction between the main bypass switch 32 and the sub-bypass switch 42, they may be collectively referred to as the "bypass switch."

[0019] The main power switch 31 is provided on a power supply line between the main power supply 10 and the load. Specifically, the main power switch 31 is provided on the main power supply line L1. The main power switch 31 is a first power switch including a pair of FETs whose body diodes have their anodes facing in opposite directions, and an inductor (coil) connected in series between the pair of FETs. When the pair of FETs is turned on, the main power switch 31 electrically connects the main power supply line L1 to the sub power supply line L2 and the load power supply line L3. When the pair of FETs is turned off, the main power switch 31 electrically disconnects the main power supply line L1 from the sub power supply line L2 and the load power supply line L3.

[0020] The main bypass switch 32 is provided on the main power supply line L1 and is connected in parallel to the main power switch 31. When the main bypass switch 32 is turned on, it electrically connects the main power supply line L1 to the sub power supply line L2 and the load power supply line L3. When the main bypass switch 32 is turned off, it electrically disconnects the main power supply line L1 from the sub power supply line L2 and the load power supply line L3.

[0021] The sub-power switch 41 is provided on the power supply line between the sub-power supply 20 and the load. Specifically, the sub-power switch 41 is provided on the sub-power supply line L2. The sub-power switch 41 is a second power switch including a pair of FETs whose body diodes have their anodes in opposite directions, and an inductor (coil) connected in series between the pair of FETs. When the pair of FETs is turned on, the sub-power switch 41 electrically connects the sub-power supply line L2 to the main power supply line L1 and the load power supply line L3. When the pair of FETs is turned off, the sub-power switch 41 electrically disconnects the sub-power supply line L2 from the main power supply line L1 and the load power supply line L3.

[0022] The sub-bypass switch 42 is provided on the sub-power feed line L2 and is connected in parallel to the sub-power switch 41. When the sub-bypass switch 42 is turned on, it electrically connects the sub-power feed line L2 to the main power feed line L1 and the load power feed line L3. When the sub-bypass switch 42 is turned off, it electrically disconnects the sub-power feed line L2 from the main power feed line L1 and the load power feed line L3.

[0023] The first load switch 51 is a switch provided on the load power supply line L3. Specifically, when the first load switch 51 is turned on, it electrically connects the first load 101 to the main power supply line L1 and the sub power supply line L2. When the first load switch 51 is turned off, it electrically disconnects the first load 101 from the main power supply line L1 and the sub power supply line L2.

[0024] The second load switch 52 is a switch provided on the load power supply line L3. Specifically, when the second load switch 52 is turned on, it electrically connects the second load 102 to the main power supply line L1 and the sub power supply line L2. When the second load switch 52 is turned off, it electrically disconnects the second load 102 from the main power supply line L1 and the sub power supply line L2.

[0025] The first sensor 61 is provided on the main power supply line L1 and detects the power supply state. Specifically, the first sensor 61 is provided between the main power switch 31 and the main power supply 10. In the present disclosure, the first sensor 61 is composed of a voltage sensor that detects the voltage of the main power supply line L1 and a current sensor that detects the current of the main power supply line L1. The first sensor 61 outputs the detected voltage and current values ​​to the controller 2.

[0026] The second sensor 62 is provided on the sub-power supply line L2 and detects the power supply state. Specifically, the second sensor 62 is provided between the sub-power switch 41 and the sub-power supply 20. In the present disclosure, the second sensor 62 is composed of a voltage sensor that detects the voltage of the sub-power supply line L2 and a current sensor that detects the current of the sub-power supply line L2. The second sensor 62 outputs the detected voltage and current values ​​to the controller 2.

[0027] The third sensor 63 is provided on the load power supply line L3 connected to the first load 101, and detects the power supply state. Specifically, the third sensor 63 is provided between the first load switch 51 and the first load 101. Here, the third sensor 63 is configured as a current sensor that detects the current on the load power supply line L3 connected to the first load 101. The third sensor 63 outputs the detected current value to the controller 2.

[0028] The fourth sensor 64 is provided on the load power supply line L3 connected to the second load 102, and detects the power supply state. Specifically, the fourth sensor 64 is provided between the second load switch 52 and the second load 102. Here, the fourth sensor 64 is configured as a current sensor that detects the current on the load power supply line L3 connected to the second load 102. The fourth sensor 64 outputs the detected current value to the controller 2.

[0029] The controller 2 includes a microcomputer having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc., and various other circuits. The controller 2 controls the on / off of each switch by having the CPU execute a power control program stored in the ROM, using the RAM as a work area. Specifically, the controller 2 controls the on / off of each of the main power switch 31, main bypass switch 32, sub-power switch 41, sub-bypass switch 42, first load switch 51, and second load switch 52.

[0030] The power supply control program may be stored in a storage device via an external communication line, etc. Also, the controller 2 may be configured partially or entirely with hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0031] In the present disclosure, the power supply control device 1 is configured such that an inductor is provided in each of the main power switch 31 and the sub power switch 41, and when a ground fault occurs, the back electromotive force of the inductor suppresses a sudden rise in current, thereby preventing a drop in the output voltage of each power supply. This point will be explained using an example of the operation of the power supply control system S shown below.

[0032] [Configuration example of power supply control system according to the embodiment] Next, an example of the operation of the power supply control system S according to the embodiment will be described with reference to Figures 1 to 10. First, an example of the operation of the power supply control system S while parked will be described with reference to Figure 1.

[0033] When the vehicle is parked, there is a low possibility that a ground fault will occur in the main power supply 10, the sub-power supply 20, or the load, so the power switch is turned off and the bypass switch is turned on, and power is supplied via the bypass switch.

[0034] Specifically, as shown in FIG. 1, when the vehicle is parked, i.e., when the ignition switch (hereinafter referred to as "IG") is off, the controller 2 turns off the main power switch 31 and the sub power switch 41 and turns on the main bypass switch 32 and the sub bypass switch 42.

[0035] As a result, power is supplied from the main power supply 10 to the load and sub-power supply 20 via the main bypass switch 32. When the IG is off, operation of the DCDC 10b is stopped and power is supplied directly from the main battery 10a to line L1. Also, while FIG. 1 shows an example in which power is supplied from the main power supply 10 to the sub-power supply 20, i.e., the sub-power supply 20 is charged, if the voltage of the main power supply 10 becomes lower than the voltage of the sub-power supply 20, power is supplied from the sub-power supply 20 to the load via the sub-bypass switch 42.

[0036] Next, an example of the operation of the power supply control system S in normal times (when there is no ground fault) while the vehicle is running will be described with reference to Fig. 2. Fig. 2 is a diagram showing the operation of the power supply control system S in normal times while the vehicle is running.

[0037] 2, while the vehicle is running, in normal conditions where no ground fault has occurred, controller 2 turns on main power supply switch 31 and turns off main bypass switch 32. Controller 2 also turns off sub power supply switch 41 and turns on sub bypass switch 42. As a result, power is supplied from main power supply 10 to the load and sub power supply 20 via main power supply switch 31, and electricity is stored in the inductor of main power supply switch 31.

[0038] Next, an example of the operation of the power supply control system S when a ground fault occurs on the main power supply 10 side will be described with reference to Figures 3 to 5. Figures 3 to 5 are diagrams illustrating an example of the operation of the power supply control system S when a ground fault occurs on the main power supply 10 side. Figure 3 shows an example in which a ground fault 200 occurs at a connection point with the main power supply 10. Figure 4 shows an example in which, after the ground fault 200 occurs, a ground fault 201 also occurs at a connection point with the first load 101.

[0039] First, the controller 2 detects the occurrence of a ground fault (ground fault location unidentified) when the voltage value (first voltage) detected by the first sensor 61 is below the ground fault threshold. Next, the controller 2 identifies the location of the ground fault as the main power supply 10 (ground fault 200) when the absolute value of the difference between the latest value and the previous value of the first voltage detected by the first sensor 61 (amount of change: latest value - previous value; the same applies below) is equal to or greater than the threshold (i.e., a sudden voltage drop). This is because when the ground fault 200 occurs on the main power supply 10 side, the first voltage drops suddenly without being affected by the back electromotive force due to the inductor of the main power supply switch 31. In other words, the controller 2 identifies the location of the ground fault as the main power supply 10 when the first voltage of the main power supply 10 is below the ground fault threshold and the amount of drop from the immediately preceding first voltage is equal to or greater than the threshold, resulting in a sudden voltage drop.

[0040] 3, when the controller 2 identifies a ground fault 200, it turns off the main power switch 31 and the main bypass switch 32, turns on the sub-power switch 41, and turns off the sub-bypass switch 42. Note that, since the main bypass switch 32 is already in the off state during normal operation as shown in FIG. 2, when the controller 2 identifies a ground fault 200, it maintains the off state of the main bypass switch 32. As a result, the ground fault location 200 is disconnected from the power feed lines L1, L2, and L3 (power supply from the main power supply 10 to the load is interrupted), and power is supplied from the sub-power supply 20 to the load. Furthermore, by turning off the main power switch 31 and the main bypass switch 32, the controller 2 can prevent current from flowing from the sub-power supply 20 to the ground fault 200. Furthermore, because main power switch 31 is normally on, controller 2 can prevent a large current from flowing from sub-power supply 20 to ground fault 200 due to back electromotive force generated by the inductor of main power switch 31 from occurring to turning off main power switch 31. In other words, it is possible to prevent the voltage of sub-power supply 20 from dropping significantly when ground fault 200 occurs.

[0041] Note that the controller 2 turns on the sub-power switch 41 and then turns off the sub-bypass switch 42. In other words, the controller 2 turns on both the sub-bypass switch 42 and the sub-power switch 41 temporarily, and then turns off the sub-bypass switch 42. This allows the controller 2 to prevent a temporary interruption of power supply to the load when the sub-bypass switch 42 is turned off.

[0042] Next, FIG. 4 illustrates a case in which a ground fault 201 occurs on the first load 101 side while a ground fault 200 occurs on the main power supply 10 side. In this case, the controller 2 first detects the occurrence of a ground fault (ground fault location unspecified) when the voltage value (second voltage) detected by the second sensor 62 falls below the ground fault threshold. If a ground fault occurs on the load side, an overcurrent flows toward the ground fault point, but the increase in current is suppressed by the influence of the back electromotive force generated by the inductor of the sub-power switch 41. On the other hand, if a ground fault occurs on the sub-power supply 20 side, the second sensor 62 is not affected by the back electromotive force generated by the inductor of the sub-power switch 41, and the second voltage detected by the second sensor 62 drops sharply. Therefore, the controller 2 determines that a ground fault has occurred on the load side when the absolute value of the change in the second voltage detected by the second sensor 62 between the latest value and the previous value is less than the threshold (i.e., a gradual voltage drop). Then, if the change in the current value detected by the third sensor 63 between the latest value and the previous value is greater than zero (i.e., the current is increasing), the controller 2 identifies a ground fault 201 at the connection point with the first load 101. That is, if the current detected by the third sensor 63 increases from the immediately preceding current, the controller 2 identifies a ground fault 201 at the connection point with the first load 101. Then, as shown in FIG. 4 , when the controller 2 identifies the ground fault 201, the controller 2 turns off the first load switch 51. This disconnects the ground fault location 201 from the power feed lines L2 and L3, and cuts off the power supply from the sub-power supply 20 to the first load 101. Furthermore, because the controller 2 turns on the sub-power supply switch 41, it is possible to prevent a large current from flowing from the sub-power supply 20 to the ground fault 201 due to the back electromotive force of the inductor of the sub-power supply switch 41 during the period from the occurrence of the ground fault 201 to the disconnection of the first load switch 51. That is, it is possible to prevent a significant drop in the voltage of the sub-power supply 20 when the ground fault 201 occurs. As a result, the controller 2 can suppress a decrease in the remaining battery power of the sub-power supply 20, and therefore can avoid a shortening of the time during which power can be supplied to the normal second load 102.

[0043] The same applies when a ground fault occurs on the second load 102 side when a ground fault 200 has occurred on the main power supply 10 side; if the absolute value of the change between the latest value and the previous value of the second voltage detected by the second sensor 62 is less than a threshold value (i.e., a gradual voltage drop) and the change between the latest value and the previous value of the current value detected by the fourth sensor 64 is greater than zero (i.e., the current is increasing), the controller 2 identifies a ground fault at the connection point with the second load 102.

[0044] 4 shows an example in which a ground fault 201 is identified on the first load 101 side. However, if a ground fault 200 occurs on the main power supply 10 side and then a ground fault occurs on the sub-power supply 20 side, as described above, the controller 2 identifies a ground fault at the connection point with the sub-power supply 20 when the absolute value of the change between the latest value and the previous value of the second voltage detected by the second sensor 62 is equal to or greater than a threshold value (i.e., a sudden voltage drop). In this case, the controller 2 brings the vehicle to an emergency stop because both the main power supply 10 and the sub-power supply 20 have failed. Note that if a ground fault 200 occurs on the main power supply 10 side and then a ground fault occurs on the sub-power supply 20 side, the current values ​​detected by the third sensor 63 and the fourth sensor 64 both decrease, and therefore the controller 2 may identify a ground fault at the connection point with the sub-power supply 20 when the change between the latest value and the previous value of the current values ​​detected by the third sensor 63 and the fourth sensor 64 are both less than zero (i.e., the current is decreasing).

[0045] Next, using Figure 5, changes in the detected values ​​of the first sensor 61 to the fourth sensor 64 during operation of the power supply control system S described in Figures 3 and 4 will be described. Figure 5 is a diagram showing changes in the detected values ​​of the first sensor 61 to the fourth sensor 64 when a ground fault occurs in the main power supply 10 and the load. Figure 5 shows changes in the voltage value V1 (first voltage) and current value I1 detected by the first sensor 61, the voltage value V2 (second voltage) and current value I2 detected by the second sensor 62, the current value I3 detected by the third sensor 63, and the current value I4 detected by the fourth sensor 64.

[0046] 5, assume that a ground fault 200 occurs in the main power supply 10 at time t1. In this case, current flows from the main power supply 10 to the point of the ground fault 200, cutting off the power supply to the power supply control device 1, causing a sudden drop in voltage V1 and current I1 from time t1 onward. On the other hand, the voltage V2 and current I2 on the sub-power supply 20 side drop more slowly because the back electromotive force of the inductor of the main power supply switch 31 prevents current from flowing from the sub-power supply 20 to the point of the ground fault 200. As a result, a large amount of current flows from the sub-power supply 20 to the first load 101 and the second load 102, causing a gradual drop in current I3 and current I4 of the second load 102.

[0047] Next, assume that at time t2, voltage value V1 becomes less than ground fault threshold value TH1. As a result, controller 2 detects the occurrence of a ground fault at time t2 and identifies the location of the ground fault. Specifically, controller 2 calculates the difference between the latest value of voltage value V1 obtained at time t2 and the previous value, and if the absolute value of the amount of change is equal to or greater than the threshold (i.e., a sudden voltage drop), controller 2 identifies the occurred ground fault as ground fault 200 on main power supply 10, and turns off main power switch 31 at time t3. Furthermore, as described with reference to FIG. 3, controller 2 turns on sub-power switch 41 and then turns off sub-bypass switch 42. As a result, at time t3, voltage value V2, current value I2, current value I3, and current value I4 return to their normal values.

[0048] Suppose that, at time t4, a ground fault 201 occurs at the connection point of first load 101. In this case, voltage value V2 on the side of sub-power supply 20 decreases and current values ​​I2 and I3 increase, but the changes are gradual because the back electromotive force of the inductor of sub-power supply switch 41 suppresses the flow of current from sub-power supply 20 to the point of ground fault 201. As a result, the current to the normal second load 102 decreases, but the decrease in current value I4 is gradual.

[0049] Next, assume that at time t5, the voltage value V2 becomes less than the ground fault threshold value TH1. As a result, the controller 2 detects the occurrence of a ground fault at time t5 and identifies the location of the ground fault. Specifically, if the absolute value of the change between the latest value and the previous value of the second voltage detected by the second sensor 62 is less than the threshold (i.e., a gradual voltage drop), the controller 2 identifies the location of the ground fault as being on the load side. Then, the controller 2 calculates the change between the latest value and the previous value of each of the current values ​​I3 and I4 at time t5, and identifies the first load 101 side where the difference between the currents has increased and is greater than zero as the location of the ground fault. After identifying the location of the ground fault, the controller 2 turns off the first load switch 51 on the first load 101 side, which is the location of the ground fault, at time t6. As a result, at time t6, the voltage value V2, the current value I2, and the current value I4 return to their normal values, and the current value I3 drops to near zero.

[0050] Next, an example of the operation of the power supply control system S when a ground fault occurs on the sub-power supply 20 side will be described with reference to Figures 6 to 8. Figures 6 to 8 are diagrams illustrating an example of the operation of the power supply control system S when a ground fault occurs on the sub-power supply 20 side. Figure 6 shows an example in which a ground fault 202 occurs at the connection point with the sub-power supply 20. Figure 7 shows an example in which, after the ground fault 202 occurs, a ground fault 201 also occurs at the connection point with the first load 101.

[0051] First, the controller 2 detects the occurrence of a ground fault (ground fault location unidentified) when the voltage value (first voltage) detected by the first sensor 61 is less than the ground fault threshold. Next, when the controller 2 detects that the absolute value of the change between the latest value and the previous value of the first voltage detected by the first sensor 61 is less than the threshold (i.e., a gradual voltage drop), the controller 2 determines whether the differences (changes) between the latest value and the previous value of the current detected by the third sensor 63 and the fourth sensor 64 are both less than zero (i.e., the current is decreasing). When the differences between the currents detected by the third sensor 63 and the fourth sensor 64 are both less than zero (i.e., the current is decreasing), the controller 2 identifies the location of the ground fault as the sub-power supply 20 (ground fault 202). This is because when a ground fault occurs on the sub-power supply 20 side, the decrease in the first voltage detected by the first sensor 61 and the decrease in the current detected by the third sensor 63 and the fourth sensor 64 become gradual due to the influence of the back electromotive force caused by the inductor of the main power switch 31. In other words, the controller 2 identifies the location of the ground fault as the sub-power supply 20 when the first voltage of the main power supply 10 is less than the ground fault threshold, the voltage drops gradually such that the drop from the immediately preceding first voltage is less than the threshold, and the currents flowing through each load have all decreased from the immediately preceding currents.

[0052] 6, when the controller 2 identifies a ground fault 202, it turns off the sub-bypass switch 42. The controller 2 maintains the main power switch 31 on, the main bypass switch 32 off, and the sub-power switch 41 off. As a result, the ground fault location 202 is disconnected from the power feed lines L1, L2, and L3 (power supply from the sub-power supply 20 to the load is cut off), and power is supplied from the main power supply 10 to the load. Furthermore, because the controller 2 keeps the main power switch 31 on, it is possible to prevent a large current from flowing from the main power supply 10 to the ground fault 202 due to the back electromotive force of the inductor of the main power supply switch 31 from occurring until the sub-bypass switch 42 is turned off. In other words, it is possible to prevent a significant drop in the voltage of the main power supply 10 when the ground fault 202 occurs.

[0053] Next, FIG. 7 illustrates a case in which a ground fault 201 occurs on the first load 101 side while a ground fault 202 occurs on the sub-power supply 20 side. In this case, first, the controller 2 detects the occurrence of a ground fault (ground fault location unidentified) when the voltage value detected by the first sensor 61 is less than the ground fault threshold value. Next, the controller 2 identifies the ground fault 201 at the connection point with the first load 101 when the absolute value of the change between the latest value and the previous value of the first voltage detected by the first sensor 61 is less than the threshold value (i.e., a gradual voltage drop) and the change between the latest value and the previous value of the current value detected by the third sensor 63 is greater than zero (i.e., the current is increasing). That is, the controller 2 identifies the ground fault 201 at the connection point with the first load 101 when the current detected by the third sensor 63 increases from the immediately preceding current. Then, as shown in FIG. 7, when the controller 2 identifies the ground fault 201, it turns off the first load switch 51. As a result, the ground fault location 201 is disconnected from the power supply lines L1 and L3, and the power supply from the main power supply 10 to the first load 101 is cut off. Furthermore, because the controller 2 keeps the main power supply switch 31 on, it is possible to prevent a large current from flowing from the main power supply 10 to the ground fault 201 due to the back electromotive force of the inductor of the main power supply switch 31 from occurring until the first load switch 51 is cut off. In other words, it is possible to prevent the voltage of the main power supply 10 from dropping significantly when the ground fault 201 occurs. As a result, the controller 2 can prevent a drop in the remaining battery capacity of the main power supply 10, and therefore avoid a shortened time during which power can be supplied to the normal second load 102.

[0054] 7 shows an example in which ground fault 201 is identified on the first load 101 side. However, if a ground fault occurs on the main power supply 10 side while ground fault 202 has occurred on the sub-power supply 20 side, controller 2 will identify a ground fault at the connection point with main power supply 10 if the absolute value of the change between the latest value and the previous value of the first voltage detected by first sensor 61 is equal to or greater than a threshold (i.e., a sudden voltage drop). In this case, controller 2 will bring the vehicle to an emergency stop because both main power supply 10 and sub-power supply 20 will fail. If a ground fault occurs on the main power supply 10 side while ground fault 202 has occurred on the sub-power supply 20 side, the current values ​​detected by third sensor 63 and fourth sensor 64 will both decrease, and therefore controller 2 may identify a ground fault at the connection point with main power supply 10 if the change between the latest value and the previous value of the current values ​​detected by third sensor 63 and fourth sensor 64 is less than zero.

[0055] Next, changes in the detection values ​​of the first sensor 61 to the fourth sensor 64 during operation of the power supply control system S described in Figures 6 and 7 will be described using Figure 8. Figure 8 is a diagram showing changes in the detection values ​​of the first sensor 61 to the fourth sensor 64 when a ground fault occurs in the sub-power supply 20 and the load.

[0056] Assume that a ground fault 202 occurs in the sub-power supply 20 at time t11 in Fig. 8. In this case, although a current flows from the main power supply 10 to the point of the ground fault 202, the current flowing to the point of the ground fault 202 is suppressed by the back electromotive force of the inductor of the main power supply switch 31. As a result, the voltage values ​​V1 and V2 gradually decrease after time t11. Furthermore, the current values ​​I1 and I2 gradually increase after time t11. Furthermore, as a result of the current flowing from the main power supply 10 to the point of the ground fault 202, the current values ​​I3 and I4 gradually decrease after time t11.

[0057] Next, assume that at time t12, the voltage value V1 falls below the ground fault threshold value TH1. As a result, the controller 2 detects the occurrence of a ground fault at time t12 and identifies the location of the ground fault. Specifically, the controller 2 determines whether the absolute value of the amount of change between the latest value and the previous value of the voltage value V1 obtained at time t12 is less than the threshold value (i.e., a gradual voltage drop) and whether the differences (amounts of change) between the latest value and the previous value of each of the current values ​​I3 and I4 are both less than zero (i.e., a current decrease). If both differences are less than zero, the controller 2 identifies the location of the ground fault as the sub-power supply 20 (ground fault 202) and turns off the sub-bypass switch 42 at time t13. As a result, the voltage value V2 and the current value I2 fall to near zero at time t13. At time t13, the ground fault location 202 is disconnected from the power supply lines L1, L2, and L3, and the voltage value V1, the current value I1, the current value I3, and the current value I4 return to their normal values.

[0058] Suppose that, at time t14, a ground fault 201 occurs at the connection point of first load 101. In this case, voltage value V1 on the main power supply 10 side decreases and current values ​​I1 and I3 increase, but the changes are gradual because the back electromotive force of the inductor of main power supply switch 31 suppresses the flow of current from main power supply 10 to the point of ground fault 201. As a result, the current to normal second load 102 decreases, but the decrease in current value I4 is gradual.

[0059] Next, assume that at time t15, the voltage value V1 becomes less than the ground fault threshold value TH1. As a result, the controller 2 detects the occurrence of a ground fault at time t15 and identifies the location of the ground fault. Specifically, the controller 2 calculates the difference between the latest value and the previous value at time t15 for each of the current value I3 and the current value I4. If at least one of the differences is greater than zero (i.e., the current has increased), the controller 2 identifies the location of the ground fault as being on the load side. More specifically, the controller 2 identifies the first load 101 side where the difference is greater than zero and the current has increased as the location of the ground fault. Then, after identifying the location of the ground fault, the controller 2 turns off the first load switch 51 on the first load 101 side, which is the location of the ground fault, at time t16. As a result, at time t16, the ground fault location 201 is disconnected from the power supply lines L1 and L3, the voltage value V1, the current value I1, and the current value I4 return to their normal values, and the current value I3 drops to near zero.

[0060] Next, an example of the operation of the power supply control system S when a ground fault 201 occurs on the load side will be described with reference to Figures 9 and 10. Figures 9 and 10 are diagrams for explaining an example of the operation of the power supply control system S when a ground fault 201 occurs on the load side.

[0061] First, the controller 2 detects the occurrence of a ground fault (ground fault location unidentified) when the voltage value (first voltage) detected by the first sensor 61 is less than the ground fault threshold. Next, the controller 2 determines whether the absolute value of the amount of change between the latest value and the previous value of the first voltage detected by the first sensor 61 is less than the threshold (i.e., a gradual voltage drop) and whether the amounts of change between the latest value and the previous value of the current detected by the third sensor 63 and the fourth sensor 64 are both less than zero (i.e., the current is decreasing). For example, the controller 2 identifies the location of the ground fault as the first load 101 (ground fault 201) when the absolute value of the amount of change between the latest value and the previous value of the first voltage detected by the first sensor 61 is less than the threshold (i.e., a gradual voltage drop) and the amount of change between the latest value and the previous value detected by the third sensor 63 is greater than zero (i.e., the current is increasing). That is, the controller 2 identifies the location of the ground fault as the load when the first voltage of the main power supply 10 is below the ground fault threshold, the voltage drops gradually such that the drop from the immediately preceding first voltage is less than the threshold, and the current flowing through the load increases from the immediately preceding current. This is because when a ground fault occurs on the load side, the effect of the back electromotive force due to the inductor of the main power supply switch 31 causes the change in the drop in the first voltage detected by the first sensor 61 to become gradual, and also the change in the drop in the current of a normal load, among the currents detected by the third sensor 63 and the fourth sensor 64, becomes gradual, while the current of the grounded load increases.

[0062] 9, when the controller 2 identifies a ground fault 201, it turns off the first load switch 51. This disconnects the ground fault location 201 from the power supply lines L1, L2, and L3, and cuts off the power supply from the main power supply 10 to the first load 101. Furthermore, because the controller 2 turns on the main power switch 31, it is possible to prevent a large current from flowing from the main power supply 10 to the ground fault 201 due to the back electromotive force of the inductor of the main power supply switch 31 from occurring until the first load switch 51 is cut off. In other words, it is possible to prevent a significant drop in the voltage of the main power supply 10 when the ground fault 201 occurs. As a result, the controller 2 can prevent a decrease in the remaining battery capacity of the main power supply 10, and therefore avoid a shortened time during which power can be supplied to the normal second load 102.

[0063] Next, changes in the detection values ​​of the first sensor 61 to the fourth sensor 64 during operation of the power supply control system S described in Fig. 9 will be described with reference to Fig. 10. Fig. 10 is a diagram showing changes in the detection values ​​of the first sensor 61 to the fourth sensor 64 when a ground fault occurs in the load.

[0064] First, assume that at time t21, a ground fault 201 occurs at the connection point of first load 101. In this case, voltage value V1 decreases, current value I1 increases, voltage value V2 decreases, current value I2 decreases, and current value I3 increases, but these changes are gradual because the back electromotive force of the inductor of main power supply switch 31 suppresses the flow of current from main power supply 10 to the point of ground fault 201. As a result, although the current to normal second load 102 decreases, the decrease in current value I4 is gradual.

[0065] Next, assume that at time t22, the voltage value V1 becomes less than the ground fault threshold value TH1. As a result, the controller 2 detects the occurrence of a ground fault at time t22 and identifies the location of the ground fault. Specifically, the controller 2 calculates the amount of change between the latest value and the previous value at time t22 for each of the current value I3 and the current value I4, and if at least one of the amounts of change is greater than zero (i.e., the current has increased), the controller 2 identifies the location of the ground fault as being on the load side. More specifically, the controller 2 identifies the first load 101 side where the difference is greater than zero and the current has increased as the location of the ground fault. Then, after identifying the location of the ground fault, the controller 2 turns off the first load switch 51 on the first load 101 side, which is the location of the ground fault, at time t23. As a result, at time t23, the ground fault location 201 is disconnected from the power supply lines L1, L2, and L3, the voltage value V1, the current value I1, the voltage value V2, the current value I2, and the current value I4 return to their normal values, and the current value I3 drops to near zero.

[0066] Next, the processing procedure of the power supply control device 1 according to the embodiment will be described with reference to Figures 11 to 13. Figure 11 is a flowchart showing the processing procedure of the processing for identifying the location of a ground fault in the power supply control device 1 according to the embodiment. Figure 12 is a flowchart showing the processing procedure after a ground fault in the main power supply 10 in the power supply control device 1 according to the embodiment. Figure 13 is a flowchart showing the processing procedure after a ground fault in the sub-power supply 20 in the power supply control device 1 according to the embodiment.

[0067] First, the processing procedure for identifying the location of a ground fault will be described with reference to Fig. 11. In Fig. 11, the processing starts with the main power switch 31 on, the main bypass switch 32 off, the sub power switch 41 off, and the sub bypass switch 42 on.

[0068] 11, the controller 2 first acquires a voltage value and a current value from each of the first sensor 61 to the fourth sensor 64 (step S101). Specifically, the controller 2 acquires a voltage value V1 and a current value I1 from the first sensor 61, a voltage value V2 and a current value I2 from the second sensor 62, and current values ​​I3 and I4 from the third sensor 63 and the fourth sensor 64, respectively.

[0069] Next, the controller 2 determines whether the voltage value V1 is less than the ground fault threshold (step S102). If the voltage value V1 is less than the ground fault threshold (step S102: Yes), the controller 2 determines whether the absolute value |ΔV1| of the immediately preceding ΔV1 is equal to or greater than the threshold (step S103). Specifically, the controller 2 determines whether the absolute value |ΔV1| of the immediately preceding ΔV1, which is the difference between the latest value and the previous value of the voltage value V1 acquired in step S101, is equal to or greater than the threshold (i.e., a sudden voltage drop). If the voltage value V1 is equal to or greater than the ground fault threshold (step S102: No), the controller 2 stores the voltage value and current value acquired in step S101 in the storage unit (step S114) and ends the processing. That is, if the voltage value V1 is equal to or greater than the ground fault threshold, the controller 2 determines that a ground fault has not occurred and ends the identification processing.

[0070] If the immediately preceding |ΔV1| is equal to or greater than the threshold value (step S103: Yes), the controller 2 identifies the ground fault 200 on the main power supply 10 side (step S104). Next, the controller 2 turns off the main power switch 31 (step S105), turns on the sub-power switch 41 (step S106), and turns off the sub-bypass switch 42 (step S107). Thereafter, the controller 2 resets the previous values ​​of the stored voltage and current values ​​(step S113), and ends the process.

[0071] On the other hand, in step S103, if the previous |ΔV1| is less than the threshold value (step S103: No), the controller 2 determines whether the previous ΔI3 and ΔI4 are both less than zero (step S108). Specifically, the controller 2 determines whether the previous ΔI3 and ΔI4, which are the differences between the latest and previous values ​​of the current values ​​I3 and I4 acquired in step S101, are both less than zero (i.e., the current is decreasing).

[0072] If the previous ΔI3 and ΔI4 are both less than zero (step S108: Yes), the controller 2 determines that the fault is a ground fault 202 on the sub-power supply 20 side (step S109). Next, the controller 2 turns off the sub-bypass switch 42 (step S110) and proceeds to step S113.

[0073] On the other hand, if at least one of the immediately preceding ΔI3 and ΔI4 is equal to or greater than zero (i.e., the current is increasing) (step S108: No), the controller 2 determines that a ground fault has occurred on the load side, and that the load in which the current has increased is the ground fault (e.g., ground fault 201) (step S111). Next, the controller 2 turns off the load switch of the load in which the current has increased (step S112), and proceeds to step S113. For example, if ΔI3 is equal to or greater than zero, the controller 2 turns off the first load switch 51, and if ΔI4 is equal to or greater than zero, the controller 2 turns off the second load switch 52.

[0074] Next, the processing procedure after a ground fault occurs in the main power supply 10 will be described with reference to Fig. 12. In Fig. 12, the processing starts with the main power switch 31 and main bypass switch 32 off, the sub power switch 41 on, and the sub bypass switch 42 off.

[0075] 12, the controller 2 first acquires a voltage value and a current value from each of the first sensor 61 to the fourth sensor 64 (step S201). Specifically, the controller 2 acquires a voltage value V1 and a current value I1 from the first sensor 61, a voltage value V2 and a current value I2 from the second sensor 62, and current values ​​I3 and I4 from the third sensor 63 and the fourth sensor 64, respectively.

[0076] Next, the controller 2 determines whether the voltage value V2 is less than the ground fault threshold (step S202). If the voltage value V2 is less than the ground fault threshold (step S202: Yes), the controller 2 determines whether the absolute value |ΔV2| of the immediately preceding ΔV2 is equal to or greater than a threshold (i.e., a sudden voltage drop) (step S203). Specifically, the controller 2 determines whether the absolute value |ΔV2| of the immediately preceding ΔV2, which is the difference between the latest value and the previous value of the voltage value V2 acquired in step S201, is equal to or greater than a threshold. If the voltage value V2 is equal to or greater than the ground fault threshold (step S202: No), the controller 2 stores the voltage value and current value acquired in step S201 in a storage unit (step S212) and ends the process. That is, if the voltage value V2 is equal to or greater than the ground fault threshold, the controller 2 determines that no new ground fault has occurred other than the ground fault 200 on the main power supply 10 side, and ends the process.

[0077] If the immediately preceding |ΔV2| is equal to or greater than the threshold value (step S203: Yes), the controller 2 determines that the fault is a ground fault 202 on the sub-power supply 20 side (step S204). In this case, the controller 2 brings the vehicle to an emergency stop because both the main power supply 10 and the sub-power supply 20 have failed (step S205). Thereafter, the controller 2 resets the previous values ​​of the voltage and current values ​​that it has stored (step S211) and ends the process.

[0078] On the other hand, in step S203, if the immediately preceding ΔV2 is less than the threshold (i.e., a gradual voltage drop) (step S203: No), the controller 2 determines whether or not ΔI3 of the immediately preceding ΔI3 and ΔI4 is equal to or greater than zero (i.e., the current is increasing) (step S206). Specifically, the controller 2 determines whether or not ΔI3 of the immediately preceding ΔI3 and ΔI4, which are the differences between the latest and previous values ​​of the current values ​​I3 and I4 acquired in step S201, is equal to or greater than zero.

[0079] If the immediately preceding ΔI3 is equal to or greater than zero (step S206: Yes), the controller 2 identifies the fault as the ground fault 201 on the first load 101 side (step S207). Subsequently, the controller 2 turns off the first load switch 51 (step S208) and proceeds to step S211.

[0080] On the other hand, if the immediately preceding ΔI3 is not equal to or greater than zero (step S206: No), that is, if ΔI4 is equal to or greater than zero (that is, the current is increasing), the controller 2 determines that the ground fault is on the second load 102 side (step S209). Subsequently, the controller 2 turns off the second load switch 52 (step S210), and proceeds to step S211.

[0081] Next, the processing procedure after a ground fault occurs in the sub-power supply 20 will be described with reference to Fig. 13. In Fig. 13, the processing starts with the main power switch 31 on, the main bypass switch 32 off, the sub-power switch 41 and the sub-bypass switch 42 off.

[0082] 13, the controller 2 first acquires a voltage value and a current value from each of the first sensor 61 to the fourth sensor 64 (step S301). Specifically, the controller 2 acquires a voltage value V1 and a current value I1 from the first sensor 61, a voltage value V2 and a current value I2 from the second sensor 62, and current values ​​I3 and I4 from the third sensor 63 and the fourth sensor 64, respectively.

[0083] Next, the controller 2 determines whether the voltage value V1 is less than the ground fault threshold (step S302). If the voltage value V1 is less than the ground fault threshold (step S302: Yes), the controller 2 determines whether the absolute value |ΔV1| of the immediately preceding ΔV1 is equal to or greater than a threshold (i.e., a sudden voltage drop) (step S303). Specifically, the controller 2 determines whether the absolute value |ΔV1| of the immediately preceding ΔV1, which is the difference between the latest value and the previous value of the voltage value V1 acquired in step S301, is equal to or greater than a threshold. If the voltage value V1 is equal to or greater than the ground fault threshold (step S302: No), the controller 2 stores the voltage value and current value acquired in step S301 in a storage unit (step S312) and ends the process. That is, if the voltage value V1 is equal to or greater than the ground fault threshold, the controller 2 determines that no new ground fault has occurred other than the ground fault 202 on the sub-power supply 20 side, and ends the process.

[0084] If the immediately preceding |ΔV1| is equal to or greater than the threshold value (step S303: Yes), the controller 2 determines that the fault is a ground fault 200 on the main power supply 10 side (step S304). In this case, the controller 2 brings the vehicle to an emergency stop because both the main power supply 10 and the sub-power supply 20 have failed (step S305). Thereafter, the controller 2 resets the previous values ​​of the voltage and current values ​​that it has stored (step S311) and ends the process.

[0085] On the other hand, in step S303, if the previous |ΔV1| is less than the threshold value (step S303: No), the controller 2 determines whether or not ΔI3 of the previous ΔI3 and ΔI4 is equal to or greater than zero (i.e., the current is increasing) (step S306). Specifically, the controller 2 determines whether or not ΔI3 of the previous ΔI3 and ΔI4, which are the differences between the latest and previous values ​​of the current values ​​I3 and I4 acquired in step S301, is equal to or greater than zero.

[0086] If the immediately preceding ΔI3 is equal to or greater than zero (step S306: Yes), the controller 2 identifies the fault as the ground fault 201 on the first load 101 side (step S307). Subsequently, the controller 2 turns off the first load switch 51 (step S308) and proceeds to step S311.

[0087] On the other hand, if the immediately preceding ΔI3 is not equal to or greater than zero (step S306: No), that is, if ΔI4 is equal to or greater than zero (current is increasing), the controller 2 determines that the ground fault is on the second load 102 side (step S309). Subsequently, the controller 2 turns off the second load switch 52 (step S310) and proceeds to step S311.

[0088] As described above, the power supply control device 1 according to the embodiment includes a first power switch (main power switch 31), a second power switch (sub-power switch 41), a first bypass switch (main bypass switch 32), a second bypass switch (sub-bypass switch 42), load switches 51 and 52, and a controller 2. The first power switch is provided on a first power supply line (main power supply line L1) between a first power supply (main power supply 10) and loads 101 and 102, and includes a pair of FETs whose body diode anodes are in opposite directions, and an inductor connected in series between the pair of FETs. The second power switch is provided on a second power supply line (sub-power supply line L2) between a second power supply (sub-power supply 20) and loads 101 and 102, and includes a pair of FETs whose body diode anodes are in opposite directions, and an inductor connected in series between the pair of FETs. The first bypass switch is connected in parallel to the first power switch. The second bypass switch is connected in parallel to the second power switch. The load switches 51 and 52 are provided on a load power supply line L3 that is connected to the first power supply line and the second power supply line and supplies power to the load. During normal operation while the vehicle is running, the controller 2 connects the first power switch, the second bypass switch, and the load switches 51 and 52, and cuts off the second power switch and the first bypass switch. When the controller 2 detects a ground fault, it identifies the location of the ground fault, and if the location of the ground fault is either the first power supply or the second power supply, it cuts off the power switch and bypass switch on the one power supply side where the ground fault is located, and also connects the power switch on the other power supply side and cuts off the other bypass switch.

[0089] According to the present disclosure, when the power switch on the power supply side with a ground fault is turned off, a voltage drop in the normal power supply is suppressed by the back electromotive force of the inductor of the power switch during the period from the occurrence of the ground fault until the power switch is turned off, thereby preventing the power supply to the load from being interrupted with high precision. Furthermore, even if a ground fault occurs on the load side after that, a voltage drop in the normal power supply is suppressed by the back electromotive force of the inductor of the power switch on the normal power supply, thereby preventing the power supply to the normal load where no ground fault has occurred from being interrupted with high precision.

[0090] Further advantages and modifications will readily occur to those skilled in the art. Therefore, 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 their equivalents. [Explanation of symbols]

[0091] 1 Power supply control device 2 Controller 10 Main power supply 10a main battery 20 Sub-power supply 20a sub battery 31 Main power switch 32 Main bypass switch 41 Sub power switch 42 Sub-bypass switch 51 First load switch 52 Second load switch 61 First Sensor 62 Second Sensor 63 Third Sensor 64 4th Sensor 101 1st load 102 2nd load L1 Main power supply line L2 sub-power supply line L3 Load power supply line S Power Control System

Claims

1. a first power switch provided on a power supply line between a first power supply and a load, the first power switch including a pair of FETs having body diodes whose anodes are in opposite directions to each other, and an inductor connected in series between the pair of FETs; a second power switch provided on a power supply line between a second power supply and a load, the second power switch including a pair of FETs having body diodes whose anodes are in opposite directions to each other, and an inductor connected in series between the pair of FETs; a first bypass switch connected in parallel to the first power switch; a second bypass switch connected in parallel to the second power switch; a load switch connected between a power supply line that supplies power from the first power supply or the second power supply to the load and the load; a controller that connects the first power switch, the second bypass switch, and the load switch and cuts off the second power switch and the first bypass switch during normal operation while the vehicle is running; Equipped with The controller When a ground fault is detected, the location of the ground fault is identified, and if the location of the ground fault is either the first power supply or the second power supply, the power switch and bypass switch on the side of the power supply where the ground fault is located are turned off, and the power switch on the side of the other power supply is turned on and the other bypass switch is turned off. Power control device.

2. The controller If the first voltage of the first power source is less than a ground fault threshold and the amount of drop from the immediately preceding first voltage is equal to or greater than a threshold, the location of the ground fault is identified as the first power source, and the first power switch, the first bypass switch, and the second bypass switch are turned off, and the second power switch is turned on. The power supply control device according to claim 1 .

3. The controller When the location of the ground fault is identified as the first power supply, the second power supply switch is connected, and then the second bypass switch is connected. The power supply control device according to claim 2 .

4. The controller After a ground fault occurs in the first power supply, if the second voltage of the second power supply is less than a ground fault threshold, the amount of decrease from the immediately preceding second voltage is less than a threshold, and the current flowing through the load increases from the immediately preceding current, the ground fault in the load is identified and the load switch connected to the load is shut off. The power supply control device according to claim 2 .

5. The controller When the first voltage of the first power supply is less than a ground fault threshold, the amount of decrease from the immediately preceding first voltage is less than a threshold, and the current flowing through the load has decreased from the immediately preceding current, the location of the ground fault is identified as the second power supply, and the first power supply switch is connected, and the second power supply switch, the first bypass switch, and the second bypass switch are disconnected. The power supply control device according to claim 1 .

6. The controller After a ground fault occurs in the second power supply, if the first voltage of the first power supply is less than a ground fault threshold, the amount of decrease from the immediately preceding first voltage is less than a threshold, and the current flowing through the load increases from the immediately preceding current, the ground fault in the load is identified and the load switch connected to the load is shut off. The power supply control device according to claim 5 .

7. a first power switch provided on a power supply line between a first power supply and a load, the first power switch including a pair of FETs having body diodes whose anodes are in opposite directions to each other, and an inductor connected in series between the pair of FETs; a second power switch provided on a power supply line between a second power supply and a load, the second power switch including a pair of FETs having body diodes whose anodes are in opposite directions to each other, and an inductor connected in series between the pair of FETs; a first bypass switch connected in parallel to the first power switch; a second bypass switch connected in parallel to the second power switch; a load switch connected between a power supply line that supplies power from the first power supply or the second power supply to the load and the load; a controller that connects the first power switch, the second bypass switch, and the load switch and cuts off the second power switch and the first bypass switch during normal operation while the vehicle is running; Equipped with The controller When a ground fault is detected, the location of the ground fault is identified, and if the location of the ground fault is the load, the load switch connected to the load that is the location of the ground fault is turned off. Power control device.

8. The controller When the first voltage of the first power source is less than a ground fault threshold, the amount of decrease from the immediately preceding first voltage is less than a threshold, and the current flowing through the load has increased from the immediately preceding current, the location of the ground fault is identified as the load. The power supply control device according to claim 7.

9. a first power switch provided on a power supply line between a first power supply and a load, the first power switch including a pair of FETs having body diodes whose anodes are in opposite directions to each other, and an inductor connected in series between the pair of FETs; a second power switch provided on a power supply line between a second power supply and a load, the second power switch including a pair of FETs having body diodes whose anodes are in opposite directions to each other, and an inductor connected in series between the pair of FETs; a first bypass switch connected in parallel to the first power switch; a second bypass switch connected in parallel to the second power switch; a power supply control program to be executed by a computer including a power supply line that supplies power from the first power supply or the second power supply to the load, and a load switch connected between the power supply line and the load, causing the computer to execute a procedure of connecting the first power switch, the second bypass switch, and the load switch and disconnecting the second power switch and the first bypass switch during normal operation while the vehicle is running; The procedure comprises: When a ground fault is detected, the location of the ground fault is identified, and if the location of the ground fault is either the first power supply or the second power supply, the power switch and bypass switch on the side of the power supply where the ground fault is located are turned off, and the power switch on the side of the other power supply is turned on and the other bypass switch is turned off. Power control program.

10. a first power switch provided on a power supply line between a first power supply and a load, the first power switch including a pair of FETs having body diodes whose anodes are in opposite directions to each other, and an inductor connected in series between the pair of FETs; a second power switch provided on a power supply line between a second power supply and a load, the second power switch including a pair of FETs having body diodes whose anodes are in opposite directions to each other, and an inductor connected in series between the pair of FETs; a first bypass switch connected in parallel to the first power switch; a second bypass switch connected in parallel to the second power switch; a power supply control program to be executed by a computer including a power supply line that supplies power from the first power supply or the second power supply to the load, and a load switch connected between the power supply line and the load, causing the computer to execute a procedure of connecting the first power switch, the second bypass switch, and the load switch and disconnecting the second power switch and the first bypass switch during normal operation while the vehicle is running; The procedure comprises: When a ground fault is detected, the location of the ground fault is identified, and if the location of the ground fault is the load, the load switch connected to the load that is the location of the ground fault is turned off. Power control program.

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