Power supply system and power supply control device

Abstract

This aims to enable the restoration of power supply to loads that can receive power in the event of a ground fault as quickly as possible, while also improving the accuracy of identifying the location of the ground fault. [Solution] When the ground fault detection unit detects a ground fault, it performs a first tripping operation to switch switch CPSW to the off state, then performs a location identification operation to identify the location of the ground fault after the first tripping operation, and then performs a second tripping operation after the location identification operation. In the location identification operation, the ground fault detection unit performs overcurrent detection to detect whether or not an overcurrent flows in the switch SWL, SWR and the direction of the overcurrent, and undervoltage detection to detect whether or not the voltage of switch CPSW is low voltage, and identifies the location of the ground fault based on the results of the overcurrent detection and undervoltage detection, and in the second tripping operation, it switches the switch closest to the identified location of the ground fault among the switches SWL, SWR provided by each of the isolators X1 to X4 to the off state.

Description

Technical Field

[0004] ,

[0001] The present invention relates to a power supply system and a power supply control device for supplying power to a load.

Background Art

[0002] Conventionally, as an auxiliary power supply system among power supply systems for supplying power to various loads mounted on a vehicle such as an automobile, a redundant power supply system that enables power supply to a load from two power sources has been proposed. The reasons for requiring a redundant power supply system include, for example, the need to ensure redundancy as a regulatory requirement when the level of autonomous driving reaches level 3 or higher. As one such redundant power supply system, a ring-type redundant power supply can be cited, in which the main line serving as the power supply path is circular and all loads are connected to the main line.

[0003] In the system of the ring-type redundant power supply, a power supply control device for controlling power supply to each of a plurality of loads is provided, and it is possible to individually cut off the power supply to each load. The power supply control device is also referred to as an isolator. In addition, the system of the ring-type redundant power supply is provided with a function of detecting a ground fault in the power supply path. When a ground fault is detected, in order to avoid stopping power supply to all loads due to the influence of the ground fault, it is possible to cut off and isolate the ground fault location by the operation of the isolator.

[0004] Patent Document 1 discloses a technique in which each isolator detects a ground fault based on whether an overcurrent associated with an abnormality flows between the terminals of its own device and the direction of the overcurrent, identifies the location where the ground fault occurs, and switches the switch of the isolator closest to the identified location where the ground fault occurs to the off state. Hereinafter, the technique disclosed in Patent Document 1 may be referred to as the prior art.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-108220 [Overview of the project] [Problems that the invention aims to solve]

[0006] Conventional technology employs a one-stage shutdown system, which involves detecting a ground fault, identifying the location of the fault, and then shutting off the power supply. However, this one-stage shutdown system is difficult to detect and improve detection accuracy because it requires identifying the fault location and shutting off the power supply within a relatively short period. Therefore, a two-stage shutdown system can be considered as a response to ground fault detection in a ring-type redundant power supply system. In a two-stage shutdown system, when a ground fault is detected, the power supply path is first separated into two systems by turning off a specific switch, for example, within a relatively short period of 100 μs or less. As a result, power supply continues to all loads that receive power from the system that does not contain the location of the ground fault.

[0007] In a two-stage interruption, this state is established, and then the location of the ground fault is identified over a relatively long period of time, for example, about 100ms. With this two-stage interruption, although the power supply to all loads is cut off for the initial short period, power supply to the minimum necessary loads is then restored, and this state continues, allowing time to identify the location of the ground fault. As a result, the accuracy of ground fault detection can be improved.

[0008] However, in a ring-type redundant power supply system, a configuration that applies a two-stage interruption as a response to ground fault detection may lead to the following problems. Specifically, in such a configuration, the overcurrent state of each isolator changes due to the initial interruption, which may lead to errors in identifying the location of the ground fault based on the overcurrent. If the location of the ground fault is incorrectly identified, it may become impossible to turn off the appropriate switch, potentially resulting in the interruption of power supply to loads that should have continued to receive power.

[0009] The present invention has been made in view of the above circumstances, and its purpose is to provide a power supply system and a power supply control device that can improve the accuracy of identifying the location of a ground fault while enabling the restoration of power supply to loads that can receive power in the shortest possible time when a ground fault occurs. [Means for solving the problem]

[0010] The power supply system according to claim 1 includes: a first power supply (2) that generates power to supply a plurality of loads (LD, LD1~LD5); a second power supply (3) which is a power supply separate from the first power supply and generates power to supply the plurality of loads; a ring-shaped power supply path (4, 32) for supplying power to the plurality of loads from the first power supply and the second power supply; a plurality of power supply control devices (X, X1~X4, Y, Y1~Y5) that control the power supply to each of the plurality of loads; and a power supply connection provided in any of the plurality of power supply control devices, which, when turned on, connects the power supply path. The system includes a crosspoint switch (CPSW, CPSW1~CPSW4, SWR2, SWL3, SWL4, SWR5) which is provided to switch the state to a first connection state in which power can be supplied to all of the multiple loads from both the first power supply and the second power supply, and which, when turned off, switches to a second connection state in which power can be supplied to some of the multiple loads from the first power supply and to some of the multiple loads from the second power supply, and a ground fault detection unit (16, 33) which detects ground faults in the power supply path.

[0011] Each of the plurality of power supply control devices includes a first switch (SWL, SWL1~SWL5) and a second switch (SWR, SWR1~SWR5) connected in series to interpose in series with the power supply path, a power supply terminal (Pc) connected to an interconnection node (Na) to which one terminal of each of the first and second switches is connected and also connected to the load, a first terminal (Pa) connected to the other terminal of the first switch, a second terminal (Pb) connected to the other terminal of the second switch, and a switch control unit (12) that controls the on / off state of the first and second switches. When the ground fault detection unit detects a ground fault, it performs a first tripping operation to switch the cross point switch to the off state, performs a identification operation to identify the location of the ground fault after the first tripping operation, and performs a second tripping operation after the identification operation.

[0012] In the specified operation, an overcurrent determination is performed to determine whether an overcurrent exceeding a predetermined current value flows through the first switch and the second switch and the direction of the overcurrent, and an undervoltage determination is performed to determine whether the voltage of the crosspoint switch is below a predetermined voltage value. Based on the results of the overcurrent determination and the undervoltage determination, the location of the ground fault is identified. In the second tripping operation, the switch control unit switches the switch closest to the identified location of the ground fault among the first switch and the second switch provided in each of the plurality of power supply control devices to the off state.

[0013] According to the above configuration, when a ground fault is detected, the ground fault detection unit performs the first tripping operation, the identification operation, and the second tripping operation in this order, that is, it performs the two-stage tripping described in the conventional technology. As a result, although the power supply to all loads is cut off for the initial short period, the power supply to the minimum necessary loads is then restored, and this state continues, allowing time to identify the location of the ground fault, thereby improving the accuracy of ground fault detection.

[0014] Furthermore, with the above configuration, the ground fault detection unit, in a specific operation, identifies the location of the ground fault not only by determining the overcurrent but also by considering whether the voltage of the crosspoint switch is low or not. Therefore, with the above configuration, even if the overcurrent state changes due to the first tripping operation, the location of the ground fault can be identified with high accuracy. Consequently, with the above configuration, it is possible to restore power supply to loads that can receive power when a ground fault occurs in the shortest possible time while improving the accuracy of identifying the location of the ground fault. [Brief explanation of the drawing]

[0015] [Figure 1] A schematic diagram showing the configuration of the power supply system according to the first embodiment. [Figure 2] A schematic diagram showing the functions of the controller according to the first embodiment. [Figure 3] This figure shows a specific example of the configuration of a switch provided in the isolator according to the first embodiment. [Figure 4] A diagram showing an example of a condition table for specific operations and second shutdown operations according to the first embodiment. [Figure 5] This diagram illustrates the state of the power supply system when a ground fault occurs in cases "1A" and "1B" according to the first embodiment. [Figure 6] Diagram illustrating the state of the power supply system when a ground fault occurs in cases "1C" and "1D" according to the first embodiment. [Figure 7] Diagram illustrating the state of the power supply system when a ground fault occurs in cases "2A" and "2B" according to the first embodiment. [Figure 8] Diagram illustrating the state of the power supply system when a ground fault occurs in cases "2C" and "2D" according to the first embodiment. [Figure 9] This diagram shows an example of a series of operations performed by the power supply system according to the first embodiment as a flowchart. [Figure 10] Figure 1 illustrates an example of a specific operational image of the power supply system according to the first embodiment. [Figure 11] Figure 2 for explaining an example of a specific operation image of the power supply system according to the first embodiment [Figure 12] Figure 3 for explaining an example of a specific operation image of the power supply system according to the first embodiment [Figure 13] Figure 4 for explaining an example of a specific operation image of the power supply system according to the first embodiment [Figure 14] Figure 5 for explaining an example of a specific operation image of the power supply system according to the first embodiment [Figure 15] Timing chart schematically showing the modes of each signal and each current in the period before and after the ground fault occurs according to the first embodiment [Figure 16] Timing chart schematically showing the modes of each signal and each current in the period when the specific operation and the second cutoff operation according to the first embodiment are performed [Figure 17] Timing chart schematically showing the modes of each signal and each current in the period after the second cutoff operation according to the first embodiment is performed [Figure 18] Diagram schematically showing the configuration of the power supply system according to the first modification of the first embodiment [Figure 19] Diagram schematically showing the configuration of the power supply system according to the second modification of the first embodiment [Figure 20] Diagram schematically showing the configuration of the power supply system according to the second embodiment and explaining the state of the power supply system when ground faults occur in the cases of "1E" and "1F" [Figure 21] Diagram schematically showing the configuration of the power supply system according to the second embodiment and explaining the state of the power supply system when ground faults occur in the cases of "1G" and "1H" [Figure 22] Diagram schematically showing the configuration of the power supply system according to the second embodiment and explaining the state of the power supply system when ground faults occur in the cases of "2E" and "2F" [Figure 23] Diagram schematically showing the configuration of the power supply system according to the second embodiment and explaining the state of the power supply system when ground faults occur in the cases of "2G" and "2H" [Figure 24] This diagram schematically shows the configuration of the power supply system according to the second embodiment and explains the state of the power supply system when a ground fault occurs in the cases of "1EE" and "2EE". [Figure 25] This diagram schematically shows the functions of the controller according to the second embodiment. [Figure 26] A diagram showing an example of a condition table for specific operations and second shutdown operations according to the second embodiment. [Figure 27] This diagram schematically shows the configuration of the power supply system according to the first modified example of the second embodiment. [Figure 28] This diagram schematically shows the configuration of the power supply system according to a second modified example of the second embodiment. [Modes for carrying out the invention]

[0016] Several embodiments will be described below with reference to the drawings. In each embodiment, substantially identical components are denoted by the same reference numerals and their descriptions are omitted. (First Embodiment) The first embodiment will be described below with reference to Figures 1 to 19.

[0017] <Overall configuration of the power supply system> As shown in Figure 1, the power supply system 1 of this embodiment is installed in a vehicle such as an automobile with an autonomous driving function, and supplies power to a plurality of loads LD installed in the vehicle. In Figure 1 and other figures, four of the loads LD are shown, and numbers are added to the end of the reference numerals to distinguish these four loads LD. In this specification, each component provided in the power supply system 1 corresponding to the four loads LD1, LD2, LD3, and LD4 may also be distinguished by adding similar numbers to the end of the reference numerals. However, if there is no need to distinguish these components, the numbers at the end will be omitted and they will be referred to collectively.

[0018] Multiple loads LD include sensors and actuators used to realize autonomous driving. Power supply system 1 is configured to supply power from both of its two power sources, the first power supply 2 and the second power supply 3, in order to achieve Fail Operational for these multiple loads LD. In the following description, Fail Operational may be abbreviated as FOP. In this embodiment, loads LD1 to LD4 are all general loads, i.e., FOP-independent loads. FOP is an abbreviation for Fail Operational. Loads LD1 to LD4 are devices that, even if they stop operating in the worst case of power failure, will have little impact on the safety of the vehicle. Loads LD1 to LD4 are loads in which power failure is acceptable. Examples of loads LD1 to LD4 include motors used in power windows, actuators used in door locks, and motors used in power seats.

[0019] Power supply system 1 is a ring-type redundant power supply system that performs a two-stage shutdown. Power supply system 1 includes a first power supply 2, a second power supply 3 which is separate from the first power supply 2, power lines 4a to 4d, and four isolators X corresponding to each of the four loads LD. The first power supply 2 and the second power supply 3 generate power to supply multiple loads LD and are rechargeable DC voltage sources.

[0020] For the first power supply 2 and the second power supply 3, for example, secondary batteries such as lead-acid batteries, nickel-metal hydride batteries, and lithium-ion batteries, and capacitors can be used. In this case, the first power supply 2 is a lead-acid battery, and the second power supply 3 is a lithium-ion battery. The high-potential terminal of the first power supply 2 is connected to power line 4a, and its low-potential terminal is connected to ground, which serves as the reference potential for various circuits. The high-potential terminal of the second power supply 3 is connected to power line 4c, and its low-potential terminal is connected to ground, which serves as the reference potential for various circuits.

[0021] Power line 4a is connected to the first terminal Pa of isolator X1 and the first terminal Pa of isolator X3. Power line 4b is connected to the second terminal Pb of isolator X1 and the first terminal Pa of isolator X2. Power line 4c is connected to the second terminal Pb of isolator X2 and the second terminal Pb of isolator X4. Power line 4d is connected to the first terminal Pa of isolator X4 and the second terminal Pb of isolator X3.

[0022] In this configuration, power lines 4a to 4d are connected in a ring shape via isolators X1 to X4, thereby forming a ring-shaped main line 4. The main line 4 functions as a power supply path for supplying power from the first power supply 2 and the second power supply 3 to multiple loads LD. Isolators X1 to X4 are provided to enable and disable the power supply path to each of the multiple loads LD1 to LD4. In other words, isolators X1 to X4 function as power supply control devices that control the power supply to each of the multiple loads LD1 to LD4. Thus, in the above configuration, all of the multiple loads LD1 to LD4 are connected to the main line 4 via isolators X1 to X4.

[0023] Each of the multiple isolators X is located in a zone ECU mounted in the vehicle. ECU stands for Electronic Control Unit. In power supply system 1, one of the multiple isolators X functions as the master, while the other isolators X function as slaves. In this case, isolator X2 functions as the master, and isolators X1, X3, and X4 function as slaves.

[0024] In this embodiment, if the master isolator X2 experiences any malfunction and is unable to fully perform its function as a master, one of the slave isolators X1, X3, or X4 will take over as the master in place of isolator X2.

[0025] Each of the multiple isolators X comprises a switch SWL, a switch SWR, a first terminal Pa, a second terminal Pb, a power supply terminal Pc, and a controller C. Switch SWL functions as the first switch, and switch SWR functions as the second switch. Switches SWL and SWR are connected in series to interpose in series with the main line 4. The power supply terminal Pc is connected to an interconnection node Na to which one terminal each of switches SWL and SWR are connected, and is also connected to the load LD.

[0026] The first terminal Pa is directly or indirectly connected to the other terminal of switch SWL. The second terminal Pb is directly or indirectly connected to the other terminal of switch SWR. Isolators X2 and X3 are equipped with a switch CPSW in addition to the above configuration. Switch CPSW2 of isolator X2 is connected between the other terminal of switch SWR2 and the second terminal Pb. Switch CPSW3 of isolator X3 is connected between the other terminal of switch SWL3 and the first terminal Pa.

[0027] The switch CPSW is installed in one of the multiple isolators X and is designed to switch the connection state of the main line 4 to the first connection state when turned on, and to switch to the second connection state when turned off, and functions as a crosspoint switch. The first connection state is a state in which power can be supplied to all of the multiple loads LD from both the first power supply 2 and the second power supply 3, that is, a state in which the energization path by the main line 4 forms a ring.

[0028] The second connection state is a state in which power can be supplied from the first power supply 2 to loads LD1 and LD2, which are part of the multiple loads LD, and power can also be supplied from the second power supply 3 to loads LD3 and LD4, which are part of the multiple loads LD. Specifically, in the second connection state, the main line 4, which is the power supply path, is divided into a primary supply path from the first power supply 2 to loads LD1 and LD2, which are part of the multiple loads LD, and a secondary supply path from the second power supply 3 to loads LD3 and LD4, which are part of the multiple loads LD. Thus, in the second connection state, the energization path by the main line 4 is a non-ring-shaped state.

[0029] <Controller Configuration> Controller C controls the operation of isolator X. Controllers C1 to C4, which are included in isolators X1 to X4, have multiple functional blocks as shown in Figure 2. Each of these functional blocks can be implemented by software using an MPU, by hardware, or through the collaboration of software and hardware. Controller C can be composed of various circuits and other hardware, or it can be configured to include an MPU in addition to these. MPU is an abbreviation for Micro Processor Unit.

[0030] In this embodiment, controllers C1, C3, and C4 are composed of various hardware components, while controller C2 is composed of various hardware components and an MPU. Controller C is configured to receive power from the first power supply 2 and the second power supply 3 via the main line 4, as well as from a separate power supply. As a result, controller C, and consequently the isolator X, can operate even when a ground fault occurs in the main line 4.

[0031] Controllers C1 to C4 include an overcurrent detection unit 11, a switch control unit 12, and a communication unit 13. Controllers C2 and C3 include an undervoltage detection unit 14 in addition to the above configurations. Controller C2 also includes an operation control unit 15 in addition to the above configurations. The overcurrent detection unit 11 detects whether an overcurrent exceeding a predetermined current value flows through switches SWL and SWR, and if an overcurrent flows, it detects the direction of the overcurrent.

[0032] The predetermined current value described above is set based on the value of the current that flows when a ground fault occurs in the main line 4, and specifically, it is set to a value that is smaller by a predetermined margin than the value of the current when a ground fault occurs. The overcurrent detection unit 11 can detect the presence or absence of an overcurrent and the direction of the overcurrent based, for example, on the terminal voltage of a shunt resistor that is provided to detect the current flowing through the switch SWL and switch SWR.

[0033] The low-voltage detection unit 14 detects whether the voltage of the terminal connected to the first power supply 2 or the second power supply 3, either the first terminal Pa or the second terminal Pb, or in other words, the voltage of the switch CPSW, is below a predetermined voltage value. In this case, the low-voltage detection unit 14 in controller C2 detects whether the voltage on the second terminal Pb side of switch CPSW2 is low. Also, in this case, the low-voltage detection unit 14 in controller C3 detects whether the voltage on the first terminal Pa side of switch CPSW3 is low. The predetermined voltage value described above is set based on the voltage value of switch CPSW when a ground fault occurs in the main line 4, and specifically, it is set to a value that is higher by a predetermined margin than the voltage value at the time of the ground fault.

[0034] The switch control units 12 in controllers C1 and C4 control the on / off state of switches SWL and SWR. The switch control units 12 in controllers C2 and C3 control the on / off state of switches SWL, SWR, and CPSW. The communication unit 13 communicates with the communication units 13 of other controllers C. This makes it possible to exchange various types of information between controllers C and, consequently, between isolators X via communication. The operation control unit 15 controls various operations using various types of information provided by the slave isolators X.

[0035] In the power supply system 1, the controllers C1 to C4 of the isolators X1 to X4 cooperate by communicating with each other to function as a ground fault detection unit 16 that detects ground faults in the main line 4. In this case, the operation of the ground fault detection unit 16 is mainly performed by the operation control unit 15 of the controller C2 of the master isolator X2. The ground fault detection unit 16 can detect that a ground fault has occurred in the main line 4, provided that a low voltage is detected by at least one low voltage detection unit 14. The ground fault detection unit 16 can also detect that a ground fault has occurred in the main line 4, provided that an overcurrent is detected by at least one overcurrent detection unit 11.

[0036] When the ground fault detection unit 16 detects a ground fault, it performs a first tripping operation to switch the switch CPSW to the off state. It is desirable that the first tripping operation be implemented using only the various hardware components of the controllers C2 and C3. This allows for a quicker switch to the off state when a ground fault is detected compared to an operation implemented using not only hardware but also software such as an MPU.

[0037] The ground fault detection unit 16 is configured to perform a specific operation to identify the location of the ground fault after the first tripping operation has been performed. As will be described in detail later, in the specific operation, the ground fault detection unit 16 identifies the location of the ground fault based on the results of overcurrent detection by all overcurrent detection units 11 and the results of undervoltage detection by all undervoltage detection units 14.

[0038] The ground fault detection unit 16 is configured to perform a second tripping operation after a specific operation is performed. In the second tripping operation, the ground fault detection unit 16, via the switch control unit 12, switches the switch closest to the identified ground fault location among the switches SWL and SWR of each of the multiple isolators X to the OFF state to trip the fault. After the second tripping operation is performed, the ground fault detection unit 16 switches the switch CPSW to the ON state.

[0039] Of the operations performed by the ground fault detection unit 16, the specific operation and the second tripping operation are executed by the master controller C2 instructing the slave controllers C1, C3, and C4 to perform the respective operations via communication. The specific operation can also be performed by the master controller C2 acquiring various information from the slave controllers C1, C3, and C4 via communication and performing the operation based on that acquired information.

[0040] <Specific configuration of the switch> The specific configuration of the switch SWL and switch SWR provided by isolator X can be, for example, the configuration shown in Figure 3. In this configuration example, switch SWL comprises two series-connected transistors QLa and QLb, and a shunt resistor RL. Transistors QLa and QLb are N-channel MOSFETs, and their sources are connected to each other via the shunt resistor RL1. The drain of transistor QLa is connected to the first terminal Pa. The drain of transistor QLb is connected to the power supply terminal Pc via the interconnection node Na.

[0041] In this configuration example, the switch SWR comprises two series-connected transistors QRa and QRB, and a shunt resistor RR. Transistors QRa and QRB are N-channel MOSFETs, and their sources are connected to each other via the shunt resistor RR. The drain of transistor QRa is connected to the power supply terminal Pc via the interconnect node Na. The drain of transistor QRB is connected to the second terminal Pb.

[0042] Thus, both the SWL and SWR switches have a configuration consisting of two MOSFETs connected in series with their sources connected to each other. Alternatively, both the SWL and SWR switches can also be configured with two MOSFETs connected in series with their drains connected to each other. In these configurations, the parasitic diodes of the two MOSFETs are oriented in opposite directions. Because the parasitic diodes are oriented in opposite directions in these configurations, turning off both MOSFETs prevents current from flowing.

[0043] <Details of specific operations and second shutdown operations> The specific operation and second tripping operation performed by the ground fault detection unit 16 are carried out based on a condition table as shown in Figure 4. In Figure 4, "Input" is an item related to the specific operation and includes "Result of overcurrent detection" and "Result of undervoltage detection". "Result of overcurrent detection" is provided for each of the four isolators X1 to X4, specifically for switches SWL and SWR, and indicates the presence or absence of overcurrent and the direction of the overcurrent for each switch. Note that in Figure 4 and other places where each switch is represented by a code, the "SW" included in the code corresponding to each switch is omitted.

[0044] In the "Overcurrent Detection Results" section, "0" indicates that no overcurrent flows, "→" indicates that an overcurrent flows and in the direction of flow from the first power supply 2 to the second power supply 3, i.e., to the right in Figure 1, etc., and "←" indicates that an overcurrent flows and in the direction of flow from the second power supply 3 to the first power supply 2, i.e., to the left in Figure 1, etc.

[0045] The "Low Voltage Detection Result" is provided for each of the two isolators X2 and X3, and indicates whether the voltage detected in each isolator X2 and X3 is low voltage or not. In the "Low Voltage Detection Result" item, a low voltage is represented as "Low," and a non-low voltage is represented as "0." In Figure 4, "Output" is an item related to the second tripping operation, and includes "Trip SW," which represents the switch that switches to the off state, i.e., trips, during the second tripping operation.

[0046] In Figure 4, "1A," "1B," "1C," and "1D" represent primary ground faults, that is, cases where the ground fault occurs at a location on the primary power supply path. Specifically, "1A" to "1D" represent the following cases: As shown in Figure 5, "1A" represents the case where a ground fault occurs on power line 4a. Also, as shown in Figure 5, "1B" represents the case where a ground fault occurs in the power supply path from the power supply terminal Pc of isolator X1 to the load LD1. Also, as shown in Figure 6, "1C" represents the case where a ground fault occurs on power line 4b. Also, as shown in Figure 6, "1D" represents the case where a ground fault occurs in the power supply path from the power supply terminal Pc of isolator X2 to the load LD2.

[0047] In Figure 4, "2A," "2B," "2C," and "2D" represent secondary ground faults, that is, cases where the ground fault occurs at a location on the secondary power supply path. Specifically, "2A" to "2D" represent the following cases: As shown in Figure 7, "2A" represents the case where a ground fault occurs on power line 4c. Also, as shown in Figure 7, "2B" represents the case where a ground fault occurs in the power supply path from the power supply terminal Pc of isolator X4 to the load LD4. Also, as shown in Figure 8, "2C" represents the case where a ground fault occurs on power line 4d. Also, as shown in Figure 8, "2D" represents the case where a ground fault occurs in the power supply path from the power supply terminal Pc of isolator X3 to the load LD3.

[0048] As shown in Figure 4, there are no cases in "1A" to "1D" and "2A" to "2D" where the "Input" items are exactly the same. Therefore, according to this embodiment, it is possible to identify which of the "1A" to "1D" and "2A" to "2D" cases it is, in other words, where the ground fault occurred, based on these "Input" items. The details of each case will be explained individually below.

[0049] In the case of "1A", no overcurrent will flow through switches SWL1-SWL4 and SWR1-SWR4. In the case of "1A", the voltage of switch CPSW2 will not be low. In the case of "1A", the voltage of switch CPSW3 will be low. Therefore, if the "Input" item is the same as "1A" in Figure 4, it is possible to identify that the ground fault location is power line 4a, that is, the "1A" case. In this case, the tripping switches will be switches SWL1 and SWL3, which are the switches closest to power line 4a. Note that in Figure 5 and other figures, the tripping switches are clearly indicated by being circled. Therefore, in the second tripping operation, switches SWL1 and SWL3 will be tripped.

[0050] In the case of "1B", of the switches SWL1 to SWL4 and SWR1 to SWR4, only switch SWL1 flows to the right. Note that in Figure 5 and other figures, the manner in which the overcurrent flows is represented by a wide arrow. In the case of "1B", the voltage of switch CPSW2 will not be low. In the case of "1B", the voltage of switch CPSW3 will be low. Therefore, if the "Input" item is the same as "1B" in Figure 4, it is possible to identify that the location of the ground fault is the power supply path from the power supply terminal Pc of isolator X1 to the load LD1, that is, the case of "1B". In this case, the tripping switches will be switches SWL1 and SWR1, which are the switches closest to the power supply path described above. Therefore, in the second tripping operation, switches SWL1 and SWR1 will be tripped.

[0051] In the case of "1C", a rightward overcurrent flows only through switches SWL1 and SWR1 among switches SWL1 to SWL4 and SWR1 to SWR4. In the case of "1C", the voltage of switch CPSW2 will not be low. In the case of "1C", the voltage of switch CPSW3 will be low. Therefore, if the "Input" item is the same as "1C" in Figure 4, it is possible to identify that the ground fault location is power line 4b, that is, the case of "1C". In this case, the tripping switches will be switches SWR1 and SWL2, which are the switches closest to power line 4b. Therefore, in the second tripping operation, switches SWR1 and SWL2 will be tripped.

[0052] In the case of "1D", only switches SWL1, SWR1, and SWL2 among switches SWL1 to SWL4 and SWR1 to SWR4 will experience a rightward overcurrent. In the case of "1D", the voltage at switch CPSW2 will not be low. In the case of "1D", the voltage at switch CPSW3 will be low. Therefore, if the "Input" item is the same as "1D" in Figure 4, it is possible to identify that the ground fault location is the power supply path from the power supply terminal Pc of isolator X2 to the load LD2, that is, the case of "1D". In this case, the tripping switches will be switches SWL2 and SWR2, which are the switches closest to the power supply path described above. Therefore, in the second tripping operation, switches SWL2 and SWR2 will be tripped.

[0053] In the case of "2A", no overcurrent will flow through switches SWL1-SWL4 and SWR1-SWR4. In the case of "2A", the voltage of switch CPSW2 will be low. In the case of "2A", the voltage of switch CPSW3 will not be low. Therefore, if the "Input" item is the same as "2A" in Figure 4, it is possible to identify that the ground fault location is power line 4c, that is, the "2A" case. In this case, the tripping switches will be switches SWR2 and SWR4, which are the switches closest to power line 4c. Therefore, in the second tripping operation, switches SWR2 and SWR4 will be tripped.

[0054] In the case of "2B", of switches SWL1 to SWL4 and SWR1 to SWR4, only switch SWR4 will have a leftward overcurrent. In the case of "2B", the voltage of switch CPSW2 will be low. In the case of "2B", the voltage of switch CPSW3 will never be low. Therefore, if the "Input" item is the same as "2B" in Figure 4, it is possible to identify that the ground fault location is the power supply path from the power supply terminal Pc of isolator X4 to the load LD4, that is, the case of "2B". In this case, the tripping switches will be switches SWL4 and SWR4, which are the switches closest to the power supply path described above. Therefore, in the second tripping operation, switches SWL4 and SWR4 will be tripped.

[0055] In the case of "2C", a leftward overcurrent flows only through switches SWL4 and SWR4 among switches SWL1 to SWL4 and SWR1 to SWR4. In the case of "2C", the voltage of switch CPSW2 becomes low. In the case of "2C", the voltage of switch CPSW3 does not become low. Therefore, if the "Input" item is the same as "2C" in Figure 4, it is possible to identify that the ground fault location is power line 4d, that is, the case of "2C". In this case, the tripping switches are switches SWR3 and SWL4, which are the switches closest to power line 4d. Therefore, in the second tripping operation, switches SWR3 and SWL4 will be tripped.

[0056] In the case of "2D", a leftward overcurrent flows only through switches SWR3, SWL4, and SWR4 among switches SWL1 to SWL4 and SWR1 to SWR4. In the case of "2D", the voltage of switch CPSW2 becomes low. In the case of "2D", the voltage of switch CPSW3 does not become low. Therefore, if the "Input" item is the same as "2D" in Figure 4, it is possible to identify that the ground fault location is the power supply path from the power supply terminal Pc of isolator X3 to the load LD3, that is, the case of "2D". In this case, the tripping switches are switches SWL3 and SWR3, which are the switches closest to the power supply path described above. Therefore, in the second tripping operation, switches SWL3 and SWR3 will be tripped.

[0057] The sequence of operations performed by the power supply system 1, including the ground fault detection unit 16, is as shown in Figure 9. First, in step S101, all switches SWL1 to SWL4, SWR1 to SWR4, CPSW2, and CPSW3 are turned on; in other words, all switches are turned on. After step S101 is completed, the process proceeds to step S102.

[0058] In step S102, monitoring is performed to determine whether or not a ground fault has occurred. In this case, the ground fault detection unit 16 detects the occurrence of a ground fault based on whether or not a low voltage has been detected by the low voltage detection unit 14. After step S102 is completed, the process proceeds to step S103. In step S103, it is determined whether or not a low voltage has been detected, that is, whether or not a ground fault has occurred. If a low voltage has not been detected and it is determined that no ground fault has occurred, the result in step S103 is "NO", and the process returns to step S102.

[0059] On the other hand, if a low voltage is detected and it is determined that a ground fault has occurred, the process proceeds to step S104. In step S104, switches CPSW2 and CPSW3 are turned off, meaning the first tripping operation is performed. After step S104 is completed, the process proceeds to step S105. In step S105, an operation to identify the location of the ground fault is performed, that is, an identification operation is performed.

[0060] The specific operation is performed by the transmission and reception of various information via communication between the master isolator X2 and the slave isolators X1, X3, and X4. After step S105 is completed, the process proceeds to step S106. In step S106, the switch closest to the location of the ground fault identified in step S105 is turned off, that is, the second tripping operation is performed. After step S106 is completed, the process proceeds to step S107. In step S107, switches CPSW2 and CPSW3 are turned on. After step S107 is completed, this series of operations is finished.

[0061] In this series of operations, the first period T1, which is the period from step S103 to step S104, is a relatively short time, for example, about 100 μs. In contrast, the second period T2, which is the period from step S104 to step S107, is a relatively long time, for example, about 100 ms. In other words, in this embodiment, when a ground fault is detected, the first interruption operation is performed in a short period of time to divide the main line 4 into a primary supply path and a secondary supply path, thereby supplying power to the minimum load LD, and then the location of the ground fault is identified over a relatively long period of time.

[0062] <Specific operational image of the power supply system> The specific operation of power supply system 1 will be explained with reference to Figures 10 to 17. Here, we will explain using the case of a ground fault in "1C" as an example, but the operation will be similar for other ground fault cases. Figures 15 to 17 are timing charts schematically showing the characteristics of each signal and current. Figure 15 corresponds to the period before and after the ground fault occurs, Figure 16 corresponds to the period during which specific operations and the second tripping operation are performed, and Figure 17 corresponds to the period after the second tripping operation when switches CPSW2 and SPSW3 are turned on. In Figures 15 to 17, the control signals for switches CPSW2 and CPSW3 are binary signals; they turn on the switches when they are at a relatively low level and turn off the switches when they are at a relatively high level.

[0063] First, as step S101 is executed, all switches, namely switches SWL1 to SWL4, SWR1 to SWR4, CPSW2, and CPSW3, are turned on, as shown in Figure 10. In the state shown in Figure 10, there is no ground fault, and power is supplied to all loads LD1 to LD4 from the first power supply 2 and the second power supply 3.

[0064] In this state, let's assume that a ground fault occurs in power line 4b at time ta in Figure 15. Then, as shown in Figure 11, an excessive short-circuit current flows from the first power supply 2 and the second power supply 3 towards the location of the ground fault. Specifically, at this time, a rightward overcurrent flows through switches SWL1 and SWR1, and a leftward overcurrent flows through switches SWL2, SWR2, and CPSW2. Also, at this time, the voltage of switch CPSW2 and the voltage of switch CPSW3 become low. In this state, steps S102 and S103 are executed, and the occurrence of a ground fault is detected. Note that in the state shown in Figure 11, the power supply to all loads LD is temporarily cut off due to the ground fault in power line 4b.

[0065] Upon detection of a ground fault, the first tripping operation in step S104 is executed, and switches CPSW2 and CPSW3 are turned off, as shown in Figure 12. As a result, the main line 4 is divided into a primary supply path and a secondary supply path, and the overcurrents flowing through switches SWL2, SWR2, and CPSW2 are stopped. Note that, as shown in Figure 15, the time from the point when the control signals of switches CPSW2 and CPSW3 switch from a low level to a high level until the point tb when switches CPSW2 and CPSW3 actually turn off and the currents begin to change is a delay time due to control delay, circuit delay, etc.

[0066] Because main line 4 has been split into two systems, power supply from the first power source 2 to loads LD1 and LD2 remains cut off, but power supply from the second power source 3 to loads LD3 and LD4 is restored. This is also evident from the waveforms of each load current shown in Figure 15. The period of transition from the state in Figure 11 to the state in Figure 12 corresponds to the aforementioned period T1, so the state in which power supply to all loads LD is cut off will be resolved in a relatively short period of time.

[0067] Next, step S105 is executed, and based on the results of the overcurrent detection and undervoltage detection in the state shown in Figure 12, the location of the ground fault is identified as power line 4b. Subsequently, the second tripping operation in step S106 is executed, and as shown in Figure 13, switches SW1R and SW2L closest to the location of the ground fault are turned off. As a result, the location of the ground fault is completely isolated from the power supply path from the first power supply 2 and the second power supply 3 to the load LD. Therefore, power supply to load LD1 is restored. However, for load LD2, power supply remains cut off because not only switch SW2L but also switch CPSW2 is turned off. This is also evident from the waveforms of each load current shown in Figure 16.

[0068] Finally, when step S107 is executed, switches CPSW2 and CPSW3 are turned on, as shown in Figure 14. This makes it possible to supply power to loads LD1, LD3, and LD4 from the first power supply 2, and to supply power to loads LD2, LD3, and LD4 from the second power supply 3, so that power is supplied to all loads LD from at least one of the first power supply 2 and the second power supply 3. This is also evident from the waveforms of each load current shown in Figure 17.

[0069] According to the embodiment described above, the following effects can be obtained. According to the power supply system 1 of this embodiment, the ground fault detection unit 16 performs a first interruption operation, a specific operation, and a second interruption operation in that order when a ground fault is detected, that is, it performs a two-stage interruption as described in the prior art. As a result, although the power supply to all loads LD is cut off for the initial short period from ground fault detection until the first interruption operation is performed, the main line 4 is then divided into a primary supply path and a secondary supply path when the first interruption operation is performed, thereby resuming the power supply to the minimum necessary loads LD. This state is maintained, and it becomes possible to identify the location of the ground fault over time, thereby improving the accuracy of ground fault detection.

[0070] Furthermore, according to the configuration of this embodiment, the ground fault detection unit 16, in a specific operation, identifies the location of the ground fault by considering not only the result of overcurrent detection but also the detection result of whether the voltages of switches CPSW2 and CPSW3 are low voltage. Therefore, according to the above configuration, even if the overcurrent state changes due to the first tripping operation, the location of the ground fault can be identified with high accuracy. Accordingly, according to this embodiment, it is possible to improve the accuracy of identifying the location of the ground fault while enabling the restoration of power supply to loads that can receive power in the shortest possible time when a ground fault occurs.

[0071] The effects obtained by this embodiment become even clearer when compared with the following comparative example. The comparative example has a two-stage interruption configuration similar to this embodiment, but it is configured to identify the location of the ground fault based solely on the results of overcurrent detection, similar to the prior art. Case 1A, where the ground fault location is power line 4a, as shown in Figure 5, and Case 2A, where the ground fault location is power line 4c, as shown in Figure 7, both show the same result in terms of overcurrent detection, with all switches showing "0", as shown in the conditions table in Figure 4.

[0072] Therefore, according to the comparative example, if a ground fault occurs in power line 4a or power line 4c, it may not be possible to accurately identify the location of the ground fault, and errors may occur in identifying the location of the ground fault. In contrast, according to this embodiment, the location of the ground fault is identified not only based on the results of overcurrent detection but also on the results of undervoltage detection, so as shown in the condition table in Figure 4, it is possible to accurately distinguish between case "1A" and case "2A". Therefore, according to this embodiment, the accuracy of identifying the location of the ground fault can be greatly improved compared to the comparative example.

[0073] In this embodiment, if a failure occurs in the master isolator X2, one of the slave isolators X1, X3, or X4 will function as a substitute for the master. In this way, even if the master isolator X2 fails and can no longer fully perform its function as a master, the ground fault detection unit 16 can continue to perform its operations.

[0074] Such master substitution functionality can be specifically implemented, for example, as follows: If, for example, a slave isolator X3 is an isolator that substitutes for the master's functions in the event of a master failure, then the controller C3 of isolator X3 is configured to include an MPU. Then, the controller C3 of isolator X3 performs a health check on the master's isolator X2, and if it determines from the health check that the master has failed, it substitutes for the master's functions. As for the health check, one possible method is to perform periodic communication, such as a watchdog, and determine that a failure has occurred when that communication is interrupted.

[0075] In this embodiment, the ground fault detection unit 16 is configured to switch switches CPSW2 and CPSW3 to the ON state after the execution of the second tripping operation. In this way, after the execution of the second tripping operation, power supply to all loads LD that are not affected by the location of the ground fault identified by the specific operation can be quickly restored.

[0076] <Variations regarding power supply paths> As mentioned above, the multiple load LDs include sensors and actuators used to realize autonomous driving. In other words, the multiple load LDs include equipment that must continue to operate in the event of a power failure for vehicle safety, loads where power failure is unacceptable, loads subject to FOP (Functional Operation Program), and loads that require a stable voltage supply. Taking these points into consideration, it is desirable to make the following modifications to the power supply path. Note that a stable voltage is a voltage within the operating guarantee voltage range necessary to continue the desired operation. An example of such a modification to the power supply path is the configuration shown in Figure 18.

[0077] In the power supply system 21 of the first modified example shown in Figure 18, load LD1 is an FOP-targeted load, and the other loads LD2 to LD4 are FOP-asymmetric loads. In this case, not only the power supply terminal Pc of isolator X1 but also the power supply terminal Pc of isolator X3 is connected to load LD1. In other words, the power supply system 21 is configured to supply power to load LD1 from the first power supply 2 and the second power supply 3 via isolator X1, and also to supply power to load LD1 from the first power supply 2 and the second power supply 3 via isolator X3.

[0078] In other words, in the power supply system 21, the load LD1 is configured to be able to receive power from either the primary supply path or the secondary supply path. With this modified configuration, when the main line 4 is divided into the primary supply path and the secondary supply path by the first tripping operation performed when a ground fault is detected, the power supply to the load LD1, which is the FOP target load, can be reliably resumed in a short time.

[0079] <Variations related to crosspoint switches> Power supply system 1 was configured to include a switch CPSW that functions as a crosspoint switch, separate from switches SWL and SWR, but it is not limited to this configuration. The crosspoint switch can be any switch that, when turned on, switches the connection state of the main line 4 to a first connection state, and when turned off, switches it to a second connection state.

[0080] Therefore, it is possible to modify the system so that, for example, one of the switches SWL and SWR provided by each isolator X also functions as a crosspoint switch. One example of such a modification regarding the crosspoint switch is the configuration shown in Figure 19. In the power supply system 22 of the second modified example shown in Figure 19, switches CPSW2 and CPSW3 are omitted.

[0081] However, in this case, the switch SWR2 on isolator X2 and the switch SWL3 on isolator X3 are configured to function as crosspoint switches. With this configuration, when the first disconnection operation occurs, the connection state of the main line 4 can be switched from the first connection state to the second connection state by turning off the switches SWR2 and SWL3 which function as crosspoint switches. This second modified example simplifies the configuration compared to a configuration in which a separate switch CPSW that functions as a crosspoint switch is provided.

[0082] (Second Embodiment) The second embodiment will be described below with reference to Figures 20 to 28. <Overall configuration of the power supply system> As shown in Figures 20 to 24, the power supply system 31 of this embodiment differs from the power supply system 1 of the first embodiment in that it has power supply lines 32a to 32f instead of power supply lines 4a to 4d, and isolator Y instead of isolator X. Note that some components, such as loads LD1 to LD4, are not shown in Figures 20 to 24.

[0083] Isolator Y has a configuration that is generally similar to that of Isolator X, but differs in its switch configuration. In power supply system 31, instead of Isolators Y2 and Y3, Isolators Y1 and Y4 are equipped with switches CPSW that function as crosspoint switches. Isolators Y1 and Y4 have a third terminal separate from the first terminal Pa and the second terminal Pb. Switch CPSW1 of Isolator Y1 is connected between the interconnection node Na and the third terminal. Switch CPSW4 of Isolator Y4 is connected between the interconnection node Na and the third terminal.

[0084] Power line 32a is connected to the high-potential terminal of the first power supply 2 and switch SWL1 of isolator Y1. Power line 32b is connected to switch SWR1 of isolator Y1 and switch SWL2 of isolator Y2. Power line 32c is connected to switch SWR2 of isolator Y2 and switch CPSW4 via the third terminal of isolator Y4. Power line 32d is connected to switch SWR4 of isolator Y4 and the high-potential terminal of the second power supply 3.

[0085] Power line 32e is connected to switch SWL4 of isolator Y4 and switch SWR3 of isolator Y3. Power line 32f is connected to switch SWL3 of isolator Y3 and switch CPSW1 via the third terminal of isolator Y1. In this way, power lines 32a to 32f are connected in a ring shape via isolators Y1 to Y4, thereby forming a ring-shaped main line 32.

[0086] The main line 32 functions as a power supply path for supplying power from the first power supply 2 and the second power supply 3 to multiple loads LD. Isolators Y1 to Y4 are provided to enable and disable the power supply paths to each of the multiple loads LD1 to LD4. In other words, isolators Y1 to Y4 function as power supply control devices that control the power supply to each of the multiple loads LD1 to LD4. Thus, in the above configuration, all of the multiple loads LD1 to LD4 are connected to the main line 32 via isolators Y1 to Y4.

[0087] <Controller Configuration> Isolator Y is equipped with a controller C similar to that of isolator X in the first embodiment, but with some modifications to its configuration. Specifically, in this case, as shown in Figure 25, among the controllers C1 to C4 of isolators Y1 to Y4, controllers C1 and C4 are equipped with an undervoltage detection unit 14 in addition to the overcurrent detection unit 11, switch control unit 12, and communication unit 13. In this case as well, controller C2 is equipped with an operation control unit 15 in addition to the above-mentioned configurations.

[0088] The low voltage detection unit 14 detects whether the voltage at the terminal connected to the first power supply 2 or the second power supply 3, among the first terminal Pa and the second terminal Pb, is below a predetermined voltage value. In this case, the low voltage detection unit 14 in controller C1 detects whether the voltage at the first terminal Pa side of switch SWL1 is low. In this case, the low voltage detection unit 14 in controller C4 detects whether the voltage at the second terminal Pb side of switch SWR4 is low.

[0089] The switch control units 12 in controllers C2 and C3 control the on / off switching of switches SWL and SWR. The switch control units 12 in controllers C1 and C4 control the on / off switching of switches SWL, SWR, and CPSW. In the power supply system 31, the controllers C1 to C4 in isolators Y1 to Y4 cooperate by communicating with each other to function as a ground fault detection unit 33 that detects ground faults in the main line 32. The ground fault detection unit 33 can perform the same operations as the ground fault detection unit 16 in the first embodiment.

[0090] <Details of specific operations and second shutdown operations> The specific operation and second tripping operation performed by the ground fault detection unit 16 of this embodiment are performed based on a condition table as shown in Figure 26. Figure 26 is a table that is generally similar to that of Figure 4, but differs in the following respects. In this case, the "Result of Overcurrent Detection" item is represented as "0" when no overcurrent flows and as "1" when an overcurrent flows. Also, in this case, the "Result of Lowvoltage Detection" is provided for each of the two isolators Y1 and Y4, and is an item that indicates whether the voltage detected in each isolator Y1 and Y4 is low voltage or not.

[0091] In Figure 26, "1E", "1F", "1G", "1H", and "1EE" represent primary ground faults, that is, cases where the ground fault occurs at a location on the primary power supply path. Specifically, "1E" to "1EE" represent the following cases. That is, as shown in Figure 20, "1E" represents the case where a ground fault occurs in the power supply path from the power supply terminal Pc of isolator Y1 to the load LD1.

[0092] Furthermore, as shown in Figure 20, "1F" represents the case where a ground fault occurs in power line 32b. Also, as shown in Figure 21, "1G" represents the case where a ground fault occurs in the power supply path from the power supply terminal Pc of isolator Y2 to the load LD2. Also, as shown in Figure 21, "1H" represents the case where a ground fault occurs in power line 32c. Also, as shown in Figure 24, "1EE" represents the case where a ground fault occurs in power line 32a.

[0093] In Figure 26, "2E", "2F", "2G", "2H", and "2EE" represent secondary ground faults, that is, cases where the ground fault occurs at a location on the secondary power supply path. Specifically, "2E" to "2EE" represent the following cases. That is, as shown in Figure 22, "2E" represents the case in which a ground fault occurs in the power supply path from the power supply terminal Pc of the isolator Y4 to the load LD4.

[0094] Furthermore, as shown in Figure 22, "2F" represents the case where a ground fault occurs in power line 32e. Also, as shown in Figure 23, "2G" represents the case where a ground fault occurs in the power supply path from the power supply terminal Pc of isolator Y3 to the load LD3. Also, as shown in Figure 23, "2H" represents the case where a ground fault occurs in power line 32f. Also, as shown in Figure 24, "2EE" represents the case where a ground fault occurs in power line 32d.

[0095] As shown in Figure 26, there are no cases in the "1E" to "1EE" and "2E" to "2EE" categories where the "Input" items are exactly the same. Therefore, this embodiment also makes it possible to identify which of the "1E" to "1EE" and "2E" to "2EE" cases it is, in other words, where the ground fault occurred, based on these "Input" items. The details of each case will be explained individually below.

[0096] In the case of "1EE," no overcurrent flows through switches SWL1 to SWL4 and SWR1 to SWR4. In the case of "1EE," the voltage detected by isolator Y1 will be low. In the case of "1EE," the voltage detected by isolator Y4 will not be low. Therefore, if the "Input" item is the same as "1EE" in Figure 26, it is possible to identify that the ground fault location is power line 32a, that is, the case of "1EE." In this case, the tripping switch will be switch SWL1, which is the switch closest to power line 32a. Therefore, in the second tripping operation, switch SWL1 will be tripped.

[0097] In the case of "1E", overcurrent flows only through switch SWL1 among switches SWL1 to SWL4 and SWR1 to SWR4. In the case of "1E", the voltage detected by isolator Y1 becomes low voltage. In the case of "1E", the voltage detected by isolator Y2 does not become low voltage. Therefore, if the "Input" item is the same as "1E" in Figure 26, it is possible to identify that the location of the ground fault is the power supply path from the power supply terminal Pc of isolator Y1 to the load LD1, that is, the case of "1E". In this case, the tripping switches will be switches SWR1 and CPSW1, which are the switches closest to the power supply path described above. Therefore, in the second tripping operation, switches SWR1 and CPSW1 will be tripped.

[0098] In the case of "1F", overcurrent flows only through switches SWL1 and SWR1 among switches SWL1 to SWL4 and SWR1 to SWR4. In the case of "1F", the voltage detected by isolator Y1 becomes low voltage. In the case of "1F", the voltage detected by isolator Y2 does not become low voltage. Therefore, if the "Input" item is the same as "1F" in Figure 26, it is possible to identify that the ground fault location is power line 32b, that is, the case of "1F". In this case, the tripping switches are switches SWR1 and SWL2, which are the switches closest to power line 32b. Therefore, in the second tripping operation, switches SWR1 and SWL2 will be tripped.

[0099] In the case of "1G", overcurrent flows only through switches SWL1, SWR1, and SWL2 among switches SWL1 to SWL4 and SWR1 to SWR4. In the case of "1G", the voltage detected by isolator Y1 becomes low voltage. In the case of "1G", the voltage detected by isolator Y2 does not become low voltage. Therefore, if the "Input" item is the same as "1G" in Figure 26, it is possible to identify that the ground fault location is the power supply path from the power supply terminal Pc of isolator Y2 to the load LD2, that is, the case of "1G". In this case, the tripping switches are switches SWL2 and SWR2, which are the switches closest to the power supply path described above. Therefore, in the second tripping operation, switches SWL2 and SWR2 will be tripped.

[0100] In the case of "1H", overcurrent flows only through switches SWL1, SWR1, SWL2, and SWR2 among switches SWL1 to SWL4 and SWR1 to SWR4. In the case of "1H", the voltage detected by isolator Y1 becomes low voltage. In the case of "1H", the voltage detected by isolator Y2 does not become low voltage. Therefore, if the "Input" item is the same as "1H" in Figure 26, it is possible to identify that the ground fault location is power line 32c, that is, the case of "1H". In this case, the tripping switches are switches SWR2 and CPSW4, which are the switches closest to power line 32c. Therefore, in the second tripping operation, switches SWR2 and CPSW4 will be tripped.

[0101] In the case of "2EE," no overcurrent flows through switches SWL1 to SWL4 and SWR1 to SWR4. In the case of "2EE," the voltage detected by isolator Y1 will not be low. In the case of "2EE," the voltage detected by isolator Y4 will be low. Therefore, if the "Input" item is the same as "2EE" in Figure 26, it is possible to identify that the ground fault location is power line 32d, that is, the case of "2EE." In this case, the tripping switch will be switch SWR4, which is the switch closest to power line 32d. Therefore, in the second tripping operation, switch SWR4 will be tripped.

[0102] In the case of "2E", of the switches SWL1 to SWL4 and SWR1 to SWR4, only switch SWR4 will have an overcurrent. In the case of "2E", the voltage detected by isolator Y1 will not be low. In the case of "2E", the voltage detected by isolator Y4 will be low. Therefore, if the "Input" item is the same as "2E" in Figure 26, it is possible to identify that the ground fault location is the power supply path from the power supply terminal Pc of isolator Y4 to the load LD4, that is, the case of "2E". In this case, the tripping switches will be switches SWL4 and CPSW4, which are the switches closest to the power supply path described above. Therefore, in the second tripping operation, switches SWL4 and CPSW4 will be tripped.

[0103] In the case of "2F", overcurrent flows only through switches SWL4 and SWR4 among switches SWL1 to SWL4 and SWR1 to SWR4. In the case of "2F", the voltage detected by isolator Y1 will not be low. In the case of "2F", the voltage detected by isolator Y4 will be low. Therefore, if the "Input" item is the same as "2F" in Figure 26, it is possible to identify that the ground fault location is power line 32e, that is, the case of "2F". In this case, the tripping switches will be switches SWR3 and SWL4, which are the switches closest to power line 32e. Therefore, in the second tripping operation, switches SWR3 and SWL4 will be tripped.

[0104] In the case of "2G", overcurrent flows only through switches SWR3, SWL4, and SWR4 among switches SWL1 to SWL4 and SWR1 to SWR4. In the case of "2G", the voltage detected by isolator Y1 will not be low. In the case of "2G", the voltage detected by isolator Y4 will be low. Therefore, if the "Input" item is the same as "2G" in Figure 26, it is possible to identify that the ground fault location is the power supply path from the power supply terminal Pc of isolator Y3 to the load LD3, that is, the case of "2G". In this case, the tripping switches will be switches SWL3 and SWR3, which are the switches closest to the power supply path described above. Therefore, in the second tripping operation, switches SWL3 and SWR3 will be tripped.

[0105] In the case of "2H", overcurrent flows only through switches SWL3, SWR3, SWL4, and SWR4 among switches SWL1 to SWL4 and SWR1 to SWR4. In the case of "2H", the voltage detected by isolator Y1 will not be low. In the case of "2H", the voltage detected by isolator Y4 will be low. Therefore, if the "Input" item is the same as "2H" in Figure 26, it is possible to identify that the ground fault location is power line 32f, that is, the case of "2H". In this case, the tripping switches will be switches SWL3 and CPSW1, which are the switches closest to power line 32f. Therefore, in the second tripping operation, switches SWL3 and CPSW1 will be tripped.

[0106] In the power supply system 1 of the first embodiment, the first power supply 2 and the second power supply 3 were connected between the isolators X in the main line 4. In contrast, in the power supply system 31 of this embodiment, the first power supply 2 and the second power supply 3 were connected via switches to the interconnection node Na inside the isolator Y in the main line 32. Thus, even though the power supply system 31 of the second embodiment has a different configuration from the power supply system 1 of the first embodiment, the same effects as the first embodiment can be obtained by having the ground fault detection unit 33 perform the same operation as the ground fault detection unit 16 of the first embodiment.

[0107] <Variations regarding the number of isolators> The number of isolators Y, and consequently the number of zone ECUs, is not limited to 4, but can be a positive integer of 3 or more. For example, as shown in the first modified power supply system 41 in Figure 27, the power supply system 31 may have a configuration in which isolator Y3 is omitted, that is, a configuration with three isolators Y1, Y2, and Y4. In the first modified power supply system 41, the switch SWR2 of isolator Y2 and the SWL4 of isolator Y4 function as crosspoint switches.

[0108] Furthermore, as shown in the second modified power supply system 42 in Figure 28, the power supply system 31 may be configured with an additional isolator Y5, that is, a configuration with five isolators Y1 to Y5. In the second modified power supply system 42, the switch SWL3 of isolator Y3 and the SWR5 of isolator Y5 function as crosspoint switches. Even with each of these modified configurations, the results of overcurrent detection and undervoltage detection will differ depending on the location of the ground fault, so the location of the ground fault can be accurately identified.

[0109] (Other embodiments) It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, and can be arbitrarily modified, combined, or expanded without departing from its essence. The numerical values ​​and other figures shown in each of the above embodiments are illustrative examples and are not limiting.

[0110] This disclosure is described in accordance with the embodiments, but it is understood that this disclosure is not limited to such embodiments or structures. This disclosure also includes various modifications and variations within the equivalence. In addition, various combinations and forms, as well as other combinations and forms that include only one, more, or fewer of those elements, fall within the scope and concept of this disclosure.

[0111] The control unit and its method described herein may be implemented by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. Alternatively, the control unit and its method described herein may be implemented by a dedicated computer provided by configuring a processor by one or more dedicated hardware logic circuits. Alternatively, the control unit and its method described herein may be implemented by one or more dedicated computers configured by a combination of a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by the computer on a computer-readable non-transitional tangible recording medium.

[0112] This disclosure includes, in addition to the invention described in the claims, the following inventions: [1] A first power supply (2) generates power to supply multiple loads (LD, LD1~LD5), A second power supply (3) is a power supply separate from the first power supply and generates power to supply the multiple loads, A ring-shaped power supply path (4, 32) for supplying power to the plurality of loads from the first power supply and the second power supply, Multiple power supply control devices (X, X1~X4, Y, Y1~Y5) that control the power supply to each of the aforementioned multiple loads, A crosspoint switch (CPSW, CPSW1~CPSW4, SWR2, SWL3, SWL4, SWR5) is provided so as to switch the connection state of the power supply path to a first connection state in which power can be supplied to all of the multiple loads from both the first power supply and the second power supply when turned on, and switch to a second connection state in which power can be supplied to some of the multiple loads from the first power supply and to some of the multiple loads from the second power supply when turned off, A ground fault detection unit (16, 33) for detecting a ground fault in the power supply path, Equipped with, Each of the aforementioned plurality of power supply control devices is A first switch (SWL, SWL1~SWL5) and a second switch (SWR, SWR1~SWR5) are connected in series to interpose in the aforementioned power supply path, A power supply terminal (Pc) is connected to the load and is connected to an interconnection node (Na) to which one terminal of the first switch and the second switch are connected. A first terminal (Pa) connected to the other terminal of the first switch, The second terminal (Pb) connected to the other terminal of the second switch, A switch control unit (12) that controls the on / off state of the first switch and the second switch, Equipped with, The ground fault detection unit is When the aforementioned ground fault is detected, a first tripping operation is performed to switch the crosspoint switch to the off state, a location identification operation is performed after the first tripping operation to identify the location of the ground fault, and a second tripping operation is performed after the location identification operation. In the aforementioned specific operation, overcurrent detection is performed to detect whether an overcurrent exceeding a predetermined current value flows through the first switch and the second switch and the direction of the overcurrent, and undervoltage detection is performed to detect whether the voltage of the crosspoint switch is below a predetermined voltage value. Based on the results of the overcurrent detection and the undervoltage detection, the location of the ground fault is identified. In the second interruption operation, the power supply system switches the switch closest to the identified location of the ground fault among the first and second switches provided in each of the plurality of power supply control devices to the OFF state via the switch control unit. [2] One of the aforementioned multiple power supply control devices functions as the master, and the other power supply control devices function as slaves. The power supply system described in [1], wherein the specific operation and the second tripping operation among the operations performed by the ground fault detection unit are performed by the master commanding the slave to perform each operation. [3] The power supply system described in [2], wherein if the master fails, one of the slaves takes over as the master. [4] The ground fault detection unit is A power supply system according to any one of [1] to [3], wherein the crosspoint switch is switched to the ON state after the execution of the second interruption operation. [5] The power supply system according to any one of the [1] to [4] paragraphs, wherein either the first switch or the second switch provided in each of the power supply control devices is also configured to function as the crosspoint switch. [6] The power supply system according to any one of the claims [1] to [5], wherein each of the first and second switches comprises two MOSFETs (QL1, QL2, QR1, QR2) connected in series such that their sources are connected to each other or their drains are connected to each other. [7] A first power supply (2) that generates power to supply multiple loads (LD, LD1~LD5), a second power supply (3) which is separate from the first power supply and also generates power to supply the multiple loads, a ring-shaped power supply path (4, 32) for supplying power to the multiple loads from the first and second power supplies, a plurality of power supply control devices (X, X1~X4, Y, Y1~Y5) that control the power supply to each of the multiple loads, and when turned on, the connection state of the power supply path is configured so that power is supplied to all of the multiple loads from both the first and second power supplies. A power supply control device used in a power supply system (1, 21, 22, 31, 41, 42) comprising: crosspoint switches (CPSW, CPSW1~CPSW4, SWR2, SWL3, SWL4, SWR5) provided to switch to a possible first connection state and, when turned off, enable power supply from the first power source to some of the multiple loads, and switch to a second connection state that enables power supply from the second power source to some of the multiple loads; and ground fault detection units (16, 33) for detecting ground faults in the power supply path, A first switch (SWL, SWL1~SWL5) and a second switch (SWR, SWR1~SWR5) are connected in series to interpose in the aforementioned power supply path, A power supply terminal (Pc) is connected to the load and is connected to an interconnection node (Na) to which one terminal of the first switch and the second switch are connected. A first terminal (Pa) connected to the other terminal of the first switch, The second terminal (Pb) connected to the other terminal of the second switch, A switch control unit (12) that controls the on / off state of the first switch and the second switch, Equipped with, The ground fault detection unit is When the aforementioned ground fault is detected, a first tripping operation is performed to switch the crosspoint switch to the off state, a location identification operation is performed after the first tripping operation to identify the location of the ground fault, and a second tripping operation is performed after the location identification operation. In the aforementioned specific operation, overcurrent detection is performed to detect whether an overcurrent exceeding a predetermined current value flows through the first switch and the second switch and the direction of the overcurrent, and undervoltage detection is performed to detect whether the voltage of the crosspoint switch is below a predetermined voltage value. Based on the results of the overcurrent detection and the undervoltage detection, the location of the ground fault is identified. In the second interruption operation, the power supply control device switches the switch closest to the identified location of the ground fault among the first and second switches provided in each of the plurality of power supply control devices to the OFF state via the switch control unit. [Explanation of Symbols]

[0113] 1, 21, 22, 31, 41, 42... Power supply system, 2... First power supply, 3... Second power supply, 4, 32... Main line, 11... Overcurrent detection unit, 12... Switch control unit, 14... Low voltage detection unit, 16... Ground fault detection unit, CPSW, CPSW1~CPSW4... Switches, LD, LD1~LD5... Loads, Na... Interconnection node, Pa... First terminal, Pb... Second terminal, Pc... Power supply terminal, QL1, QL2, QR1, QR2... Transistors, SWL, SWL1~SWL5... Switches, SWR, SWR1~SWR5... Switches, X, X1~X4, Y, Y1~Y5... Isolators.

Claims

1. A first power supply (2) generates power to supply multiple loads (LD, LD1 to LD5), A second power supply (3) is a power supply separate from the first power supply and generates power to supply the multiple loads, A ring-shaped power supply path (4, 32) for supplying power to the plurality of loads from the first power supply and the second power supply, Multiple power supply control devices (X, X1 to X4, Y, Y1 to Y5) that control the power supply to each of the aforementioned multiple loads, A crosspoint switch (CPSW, CPSW1 to CPSW4, SWR2, SWL3, SWL4, SWR5) is provided in one of the plurality of power supply control devices and is configured to switch the connection state of the power supply path to a first connection state in which power can be supplied to all of the plurality of loads from both the first power supply and the second power supply when turned on, and to switch to a second connection state in which power can be supplied to some of the plurality of loads from the first power supply and to some of the plurality of loads from the second power supply when turned off, A ground fault detection unit (16, 33) for detecting a ground fault in the power supply path, Equipped with, Each of the aforementioned plurality of power supply control devices is A first switch (SWL, SWL1 to SWL5) and a second switch (SWR, SWR1 to SWR5) are connected in series to interpose in the aforementioned power supply path, A power supply terminal (Pc) is connected to the load and is connected to an interconnection node (Na) to which one terminal of the first switch and the second switch are connected. A first terminal (Pa) connected to the other terminal of the first switch, The second terminal (Pb) connected to the other terminal of the second switch, A switch control unit (12) that controls the on / off state of the first switch and the second switch, Equipped with, The ground fault detection unit is When the aforementioned ground fault is detected, a first tripping operation is performed to switch the crosspoint switch to the off state, a location identification operation is performed after the first tripping operation to identify the location of the ground fault, and a second tripping operation is performed after the location identification operation. In the aforementioned specific operation, overcurrent detection is performed to detect whether an overcurrent exceeding a predetermined current value flows through the first switch and the second switch and the direction of the overcurrent, and undervoltage detection is performed to detect whether the voltage of the crosspoint switch is below a predetermined voltage value. Based on the results of the overcurrent detection and the undervoltage detection, the location of the ground fault is identified. In the second interruption operation, the power supply system switches the switch closest to the identified location of the ground fault among the first and second switches provided in each of the plurality of power supply control devices to the OFF state via the switch control unit.

2. One of the aforementioned multiple power supply control devices functions as the master, and the other power supply control devices function as slaves. The power supply system according to claim 1, wherein the specific operation and the second interruption operation among the operations performed by the ground fault detection unit are performed by the master commanding the slave to perform each operation.

3. The power supply system according to claim 2, wherein if the master fails, one of the slaves functions as a substitute for the master.

4. The ground fault detection unit is The power supply system according to claim 1, wherein the cross point switch is switched to the ON state after the execution of the second shutoff operation.

5. The power supply system according to claim 1, wherein either the first switch or the second switch provided in each of the power supply control devices is also configured to function as the crosspoint switch.

6. The power supply system according to claim 1, wherein each of the first switch and the second switch comprises two MOSFETs (QL1, QL2, QR1, QR2) connected in series such that their sources are connected to each other or their drains are connected to each other.

7. A first power supply (2) that generates power to supply multiple loads (LD, LD1 to LD5), a second power supply (3) which is a separate power supply from the first power supply and generates power to supply the multiple loads, a ring-shaped power supply path (4, 32) for supplying power to the multiple loads from the first power supply and the second power supply, a plurality of power supply control devices (X, X1 to X4, Y, Y1 to Y5) that control the power supply to each of the multiple loads, and provided in one of the plurality of power supply control devices, which, when turned on, changes the connection state of the power supply path from both the first power supply and the second power supply to the multiple loads A power supply control device used in a power supply system (1, 21, 22, 31, 41, 42) comprising: a crosspoint switch (CPSW, CPSW1 to CPSW4, SWR2, SWL3, SWL4, SWR5) that is provided to switch to a first connection state in which power can be supplied to all, and to a second connection state in which power can be supplied from the first power supply to some of the multiple loads and from the second power supply to some of the multiple loads when turned off; and a ground fault detection unit (16, 33) that detects a ground fault in the power supply path, A first switch (SWL, SWL1 to SWL5) and a second switch (SWR, SWR1 to SWR5) are connected in series to interpose in the aforementioned power supply path, A power supply terminal (Pc) is connected to the load and is connected to an interconnection node (Na) to which one terminal of the first switch and the second switch are connected. A first terminal (Pa) connected to the other terminal of the first switch, The second terminal (Pb) connected to the other terminal of the second switch, A switch control unit (12) that controls the on / off state of the first switch and the second switch, Equipped with, The ground fault detection unit is When the aforementioned ground fault is detected, a first tripping operation is performed to switch the crosspoint switch to the off state, a location identification operation is performed after the first tripping operation to identify the location of the ground fault, and a second tripping operation is performed after the location identification operation. In the aforementioned specific operation, overcurrent detection is performed to detect whether an overcurrent exceeding a predetermined current value flows through the first switch and the second switch and the direction of the overcurrent, and undervoltage detection is performed to detect whether the voltage of the crosspoint switch is below a predetermined voltage value. Based on the results of the overcurrent detection and the undervoltage detection, the location of the ground fault is identified. In the second interruption operation, the power supply control device switches the switch closest to the identified location of the ground fault among the first and second switches provided in each of the plurality of power supply control devices to the OFF state via the switch control unit.

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