Power distribution device and wire break detection method
The power distribution device in vehicles detects wire breaks using multiple paths and controlled current management, ensuring rapid identification without power disruption, enhancing safety and efficiency.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- ASTEMO LTD
- Filing Date
- 2023-03-08
- Publication Date
- 2026-05-20
AI Technical Summary
Existing power supply systems in vehicles struggle to quickly detect wire breaks while in motion without interrupting power supply, which can lead to excessive current concentration and potential damage to the power grid.
A power distribution device that supplies power through multiple paths using current detection elements and test current control units to manage current flow, allowing for rapid detection of wire breaks without interrupting power, even during vehicle motion.
Enables quick and accurate detection of wire breaks in vehicle power networks without power interruption, reducing the risk of overheating and cable damage, and optimizing cable design for reduced weight and cost.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a power distribution device mounted on a vehicle, and particularly to the detection of a failure in a power supply path.
Background Art
[0002] In recent years, with the progress of electrification and autonomous driving of automobiles, high reliability (redundancy) of in-vehicle power networks has been demanded. On the other hand, reduction of wire harnesses for power supply and high efficiency have been demanded. In a conventional in-vehicle power network, a relay box and a fuse box are provided near a battery, and power cables are laid and connected radially for each vehicle sensor and actuator. In such an in-vehicle power network, with the progress of electrification and high reliability of in-vehicle devices, the number of mounted sensors and actuators has increased, and the wire harness has increased for power supply redundancy.
[0003] As the background art in this technical field, there is the following prior art. Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2016-54617) discloses a power supply system including one or more monitoring devices for monitoring the state of a power storage unit and a control device for controlling the monitoring devices, which are supplied with power from an annular power line in which power lines are annularly connected. The control device includes a first power wiring that forms a part of the annular power line, a second power wiring connected to a power supply source and the first power wiring, a switching unit that switches between supply and cutoff of power supplied from the power supply source, and a control unit that controls the switching unit to detect an abnormality in the annular power line or an abnormality in the monitoring device. The monitoring device includes a third power wiring that forms a part of the annular power line and a fourth power wiring that supplies power to a load provided in the monitoring device connected to the third power wiring.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
[0005] The aforementioned Patent Document 1 describes a power supply system using a ring-shaped power grid with monitoring devices connected in a ring. However, it includes a switching unit that switches between supplying and cutting off power, and while the ring connection is temporarily disconnected, it collects power supply status from each monitoring device connected to the ring power grid and determines whether a break has occurred in the ring power grid. In Patent Document 1, since the ring connection is temporarily disconnected during the break diagnosis, there is a possibility that the power supply may be interrupted in a part of the ring power grid. For this reason, break detection in the power supply network described in Patent Document 1 is limited to when the vehicle is stopped.
[0006] If a portion of the circular power grid breaks while a vehicle is in motion, current paths may concentrate in specific sections of the still-powerable routes, potentially exceeding the grid's current capacity. Therefore, in vehicle-mounted power networks requiring high reliability, it is necessary to detect the break in a short time while the vehicle is in motion, and to limit the operation of onboard equipment to the extent that safety can be maintained, depending on the section where the break occurred, thereby limiting the power supplied to the equipment.
[0007] Therefore, we provide a technology that can quickly detect a disconnection in the in-vehicle power network without interrupting the power supply, even while the vehicle is in motion. [Means for solving the problem]
[0008] A typical example of the invention disclosed in this application is as follows: A power distribution device that supplies power to a vehicle load through two or more paths provided by a power trunk, comprising: a current detection element for detecting the current in the power trunk; and a test current control unit for controlling the amount of current flowing through paths other than the vehicle load according to the operating state of the vehicle load. The inspection current control unit, when the current of the power line falls below a first threshold, flows a predetermined inspection current through a path other than the vehicle load. When the current of the power line is less than a second threshold, which is set to a value smaller than the first threshold, the unit determines that the power line is broken. When the predetermined inspection current flows through a path other than the vehicle load, the unit sets the value of the first threshold higher than the value of the inspection current, and sets the value of the inspection current higher than the value of the second threshold. It is characterized by the following. [Effects of the Invention]
[0009] According to one aspect of the present invention, a disconnection in the on-board power network can be detected in a short time without interrupting the power supply, even while the vehicle is in motion. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments for carrying out the invention. [Brief explanation of the drawing]
[0010] [Figure 1A] This figure shows an example of an in-vehicle power network according to an embodiment of the present invention. [Figure 1B] This figure shows an example of an in-vehicle power network according to an embodiment of the present invention. [Figure 1C] This figure shows an example of an in-vehicle power network according to an embodiment of the present invention. [Figure 2] This diagram shows the configuration of the power distribution device 1a of the first embodiment. [Figure 3A] This figure shows the current path inside the power distribution device and the current change in the power trunk line due to the operation of the determination unit in the first embodiment. [Figure 3B] This figure shows the current path inside the power distribution device and the current change in the power trunk line due to the operation of the determination unit in the first embodiment. [Figure 4] This is a time chart of the load current IL, test current ID, and main line current IM in the first embodiment. [Figure 5] This is a time chart of the load current IL, test current ID, and main line current IM in the second embodiment. [Figure 6] This figure shows the fault diagnosis method of the third embodiment. [Figure 7] This figure shows an example configuration of the power distribution device 1a of the fourth embodiment. [Figure 8] This diagram shows the minimum currents for loads A through E. [Modes for carrying out the invention]
[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0012] (First embodiment) FIG. 1A, FIG. 1B, and FIG. 1C are diagrams showing an example of an in-vehicle power network according to this embodiment.
[0013] The in-vehicle power network shown in FIG. 1A has a plurality of power distribution devices 1a to 1d. The power distribution devices 1a to 1d are power hubs installed in each zone such as the front, right side, left side, and rear of the vehicle, and supply power to vehicle loads 2a to 2d in each zone. The power distribution devices 1a to 1d are connected in a ring shape by power main lines 3a, 3b, 3c, 3d, 3e, and 3f, and power is supplied to each of the power distribution devices 1a to 1d from a plurality of power main lines. A 12V battery 4, which is a first power source, is connected to the ring-shaped power main lines 3a and 3b. As the battery 4, a lead battery, a nickel-metal hydride battery, a lithium-ion battery, etc. can be used. Also, a DC / DC converter 5, which is a second power source, is connected to the power main lines 3e and 3f. The DC / DC converter 5 steps down the voltage of a high-voltage battery (for example, a 400V battery), which is not shown, to 12V and supplies it to the power main lines 3e and 3f. The high-voltage battery is a battery that supplies power to a driving motor for driving wheels in an electric vehicle or a hybrid vehicle. Also, instead of the DC / DC converter 5, an alternator that generates electricity by the driving force of the vehicle's engine may be connected to the power main lines 3e and 3f. That is, the first power source and the second power source may be appropriately selected as long as they are supplied from different energy sources.
[0014] In the in-vehicle power network shown in FIG. 1A, since the power main lines are connected in a ring shape, all the power distribution devices 1a to 1d can receive power supply from two systems. Even if any one of the power main lines is disconnected, the power supply to the power distribution devices 1a to 1d can be continued from another route. For example, when the power main line 3a is disconnected in FIG. 1A, power can be supplied to the power distribution device 1a from the battery 4 via the power main lines 3b, 3d, 3f, 3e, and 3c. Also, when the remaining amount of the battery 4 is small, power can be supplied to the power distribution device 1a from the DC / DC converter 5 via the power main lines 3e and 3c.
[0015] Furthermore, in the vehicle power network shown in Figure 1B, the power systems from battery 4 via power lines 3a and 3c are connected to power distribution devices 1a and 1c, and the power systems from DC / DC converter 5 via power lines 3b and 3d are connected to power distribution devices 1b and 1d. Power distribution device 1a and power distribution device 1d are connected by power line 3g, and power distribution device 1c and power distribution device 1b are connected by power line 3h. In this way, the power systems from battery 4 and DC / DC converter 5 are connected in a cross-connection manner by power lines 3g and 3h, so that all power distribution devices 1a to 1d can receive power from two separate systems, and even if one of the power lines is disconnected, power can continue to be supplied to power distribution devices 1a to 1d from another route. For example, if power line 3c is disconnected in Figure 1B, the power supply from battery 4 to power distribution device 1c will be interrupted, but power can still be supplied from DC / DC converter 5 via power lines 3b and 3h.
[0016] Furthermore, in the vehicle power network shown in Figure 1C, the power system from the battery 4 via the power trunk line 3a is connected to the power distribution device 1a, and the power system from the DC / DC converter 5 via the power trunk line 3e is connected to the power distribution device 1c, with power distribution devices 1a and 1c connected by the power trunk line 3c. In this way, since the power system from the battery 4 and the power system from the DC / DC converter 5 are connected by the power trunk line 3c, all power distribution devices 1a and 1c can receive power from two separate systems, and even if one of the power trunk lines is disconnected, power can continue to be supplied to power distribution devices 1a and 1c from another route. For example, if the power trunk line 3c is disconnected in Figure 1C, the power supply from the DC / DC converter 5 to power distribution device 1a will be interrupted, but power can still be supplied from the battery 4 via the power trunk line 3a. Similarly, the power supply from the battery 4 to power distribution device 1c will be interrupted, but power can still be supplied from the DC / DC converter 5 via the power trunk line 3e.
[0017] Figure 2 shows the configuration of the power distribution device 1a in this embodiment. The configuration example of the power distribution device 1a will be explained with reference to Figure 2, but the other power distribution devices 1b, 1c, and 1d may have the same configuration.
[0018] The power distribution device 1a is connected to the power main line 3a and the power main line 3c. The power distribution device 1a has a current detection element 6a for detecting the current flowing through the power main line 3a and a current detection element 6b for detecting the current of the power main line 3c. The current detection elements 6a and 6b can use a shunt resistor, a Hall element, or the like. The power main line 3a and the power main line 3c are connected via cutoff elements 7a and 7b. One end of the cutoff element 7a is connected to the power main line 3a, and the other end is connected to the cutoff element 7b. One end of the cutoff element 7b is connected to the cutoff element 7a, and the other end is connected to the power main line 3c. A protection circuit 8 is connected to the connection point of the cutoff element 7a and the cutoff element 7b, and power is supplied to the vehicle load 2a via the protection circuit 8. The protection circuit 8 controls the current to each of the vehicle loads 2a to switch conduction and cutoff, and also has a protection function of cutting off the power supply when detecting overcurrent or overvoltage for each of the vehicle loads 2a. The cutoff elements 7a and 7b are preferably power MOSFETs, and may also be mechanical switches such as relays.
[0019] In the above-described configuration, an inspection current load 9a and an inspection current switch 10a as an inspection current control unit are connected between the current detection element 6a and the cutoff element 7b. The inspection current load 9a may select an element that can adjust the amount of current flowing to the ground using a resistor or the like. The inspection current switch 10a can use an element that switches the conduction and cutoff of the current flowing through the circuit, such as a semiconductor switch (for example, MOS-FET).
[0020] [[ID=ll]]When a shunt resistor is used as the current detection element 6a, the power distribution device 1a has a current detection unit 11a and a determination unit 12a. The current detection unit 11a detects the current flowing through the power main line 3a from the voltage across both ends of the current detection element 6a. The determination unit 12a controls the opening and closing of the inspection current switch 10a and the cutoff element 7a based on the current value detected by the current detection unit 11a. The determination unit 12 can adopt a method of comparing with a predetermined threshold value using a comparator or a method of determining the current value digitally converted by the current detection unit 11a using a microcomputer.
[0021] The power main line 3c side has the same configuration as described above, and the power distribution device 1a has a test current load 9b, a test current switch 10b, a current detection unit 11b, and a determination unit 12b. The determination unit 12b controls the opening and closing of the interruption element 7b and the test current switch 10b according to the current flowing through the power main line 3c.
[0022] Figures 3A and 3B show the current path inside the power distribution device 1a and the current change in the power main line 3a due to the operation of the determination unit 12a.
[0023] Figure 3A shows the current path when power is supplied from the power line 3a to a vehicle load 2a connected to the power distribution device 1a. When the vehicle load 2a is operating and consuming current, a load current IL flows to the vehicle load 2a. When power is supplied from the power line 3a, the main line current IM of the power line 3a is approximately equal to the load current IL. At this time, if a break occurs in the power line 3a, the current detected by the current detection element 6a becomes zero, the determination unit 12a determines that the power line 3a is broken, and the interruption element 7a is interrupted to disconnect the power line 3a.
[0024] However, as mentioned above, if current is being consumed by the vehicle load 2a, a break in the power line 3a can be determined from the current flowing through it. However, if the vehicle load 2a is not operating, or if the vehicle load 2a is in a standby state and the load current IL is small, a misdiagnosis may occur. In other words, when the main line current IM is small, it is difficult to determine whether the vehicle load 2a is stopped or whether the power line 3a is broken.
[0025] Therefore, as shown in Figure 3B, when the main line current IM falls below a predetermined current value, the test current switch 10a is activated, allowing the test current ID to flow and increasing the main line current IM. In other words, the test current ID can be flowed according to the operating state of the vehicle load 2a based on the monitoring results of the state of the main line current IM. As a result, if the power main line 3a is normal, a main line current IM equal to or greater than the test current ID will flow. In this state, if the power main line 3a is disconnected, the detected current by the current detection element 6a becomes zero, the determination unit 12a determines that the power main line 3a is disconnected, the interruption element 7a is interrupted to disconnect the power main line 3a, the interruption element 7b is activated, and the power supply is switched to power supply from power main line 3c.
[0026] Furthermore, according to the above configuration, the power distribution device 1a notifies the higher-level system of the disconnection information it detects, thereby limiting the operation of the vehicle load 2a to the minimum load necessary for safety, or limiting the order of operation and the loads that operate simultaneously according to the priority and current capacity of the vehicle load 2a. This prevents excessive current flowing through the non-faulty power trunks among the ring-shaped power trunks, and prevents damage to the cables constituting the power trunks due to overheating. In addition, this limiting function suppresses the current flowing through the power trunks even in the event of a fault, eliminating the need to design power cables assuming worst-case scenarios, and thus reducing the cost and weight of power cables.
[0027] Figure 4 is a time chart of the load current IL, test current ID, and main line current IM.
[0028] When the load current IL decreases and the main line current IM becomes smaller than the first threshold Ith1 (=I1), the determination unit 12a conducts the test current switch 10a and the test current ID flows. The main line current IM is the sum of the load current IL and the test current ID. When the test current switch 10a conducts, the determination unit 12a updates the first threshold Ith1 to the value obtained by adding ID to I1 (I1+ID). In other words, when the test current ID flows through the test current load 9a, the first threshold Ith1 is set to be higher than the test current ID. This suppresses oscillation, where the test current switch 10a repeatedly opens and closes due to the ON / OFF of the test current. Subsequently, when the load current IL increases and the main line current IM exceeds the reset first threshold Ith1 (=I1+ID), the test current switch 10a is turned OFF to stop the test current. At this time, a second threshold Ith2 is set which is smaller than the first threshold Ith1 and also smaller than the test current ID. When the main line current IM is smaller than the second threshold Ith2, a break in the circuit is determined, and the interruption element 7a is opened to interrupt the power main line 3a. In other words, the test current ID is set to a value greater than the second threshold Ith2, which is the threshold for determining a break in the circuit. This threshold setting allows for accurate determination of a break in the circuit. The determination units 12a and 12b adjust the operating timing of the test current switches 10a and 10b so that they close at different timings.
[0029] According to the embodiment described above, it is possible to avoid interrupting the power supply by switching operations to disconnect the ring connection, as in the conventional method. Furthermore, in the method for detecting a break in the power line that monitors the current of the power trunk line, it is possible to quickly and accurately detect a break in the power line without being affected by the ON / OFF state or high / low load state of the vehicle load 2a.
[0030] Furthermore, according to this embodiment, it is not necessary to constantly supply the inspection current, the vehicle load 2a can be reduced, and since the inspection current is supplied only when the main line current decreases, power consumption for detecting open circuits can be suppressed.
[0031] Furthermore, it can not only detect disconnections in the vehicle's power network, but also pinpoint the location of the disconnection.
[0032] In this embodiment, a test current control unit consisting of a test current load 9a and a test current switch 10a is provided, but the test current control unit is not limited to this configuration. For example, the test current control unit may be configured by switching using semiconductor elements or current control using a constant current circuit, or a configuration in which a computing element such as a microcontroller or IC is connected as a load and the amount of current is controlled by the processing performed by the computing element.
[0033] (Second example) The second embodiment shows a method for controlling the test current that is even more suitable for suppressing current consumption.
[0034] Figure 5 shows the time charts for load current IL, test current ID, and main line current IM.
[0035] When the load current IL decreases and the main line current IM becomes smaller than the first threshold Ith1 (=I1), the determination unit 12a repeatedly switches the test current switch 10a ON / OFF, and a pulsed test current ID flows. The main line current IM is the sum of the load current IL and the pulsed test current ID. When the test current switch 10a conducts, the determination unit 12a determines that there is a break in the circuit if the main line current IM is smaller than the second threshold Ith2. Subsequently, when the load current IL increases and the main line current IM becomes larger than the first threshold Ith1, the ON / OFF operation of the test current switch 10a is stopped. In this configuration as well, a second threshold Ith2 smaller than the test current ID is provided, and a break in the circuit is determined when the main line current IM is smaller than the second threshold Ith2. In other words, the test current ID is set to a value greater than the second threshold Ith2, which is the threshold for determining a break in the circuit. This threshold setting allows for accurate determination of a break in the circuit.
[0036] In the second embodiment, the timing of wire break detection when the load current IL decreases depends on the ON / OFF cycle of the test current switch 10a. In other words, the timing of wire break detection may be delayed by half a cycle of the ON / OFF operation of the test current switch 10a. Therefore, it is effective in suppressing power consumption charged to the battery 4 in vehicle conditions where the requirement for wire break detection timing is relaxed, such as when the vehicle is stopped, such as when the ignition key is OFF.
[0037] According to the second embodiment, since the test current is applied in a pulsed manner, power consumption for wire break diagnosis can be suppressed.
[0038] (Third embodiment) The third embodiment shows a configuration that improves the reliability of wire break detection. The wire break detection function in the third embodiment consists of a test current load 9a, a test current switch 10a, and a determination unit 12a.
[0039] Figure 6 shows the fault diagnosis method of the third embodiment.
[0040] When the vehicle load 2a is operating and the main line current IM is greater than or equal to the first threshold Ith1 (=I1), the test current switch 10a is opened and closed to repeatedly supply a predetermined test current ID to the test current load 9a (for example, at predetermined time intervals), and it is determined whether the current detection element 6a has detected a change in the main line current IM. This allows for the diagnosis of faults in the test current load 9a and the test current switch 10a.
[0041] According to the configuration of the third embodiment, if a change in the main line current IM cannot be confirmed even when the test current switch 10a is opened and closed, it is determined that one of the components constituting the wire break detection is faulty, and the power supply from the power main line 3a is prohibited. This prevents a non-detection state due to a failure of the wire break detection function and suppresses the interruption of the power supply.
[0042] Furthermore, the diagnosis of faults in the test current load 9a and test current switch 10a in the third embodiment can be applied not only to the first embodiment but also to the second embodiment.
[0043] (Fourth embodiment) Figure 7 shows an example of the configuration of the power distribution device 1a of the fourth embodiment. The fourth embodiment differs from the previously described embodiment in that the opening and closing of the test current switch 10a is controlled based on the operating information of the vehicle load 2a and the state of the interruption elements 7a and 7b.
[0044] The protection circuit 8 acquires operational information indicating whether each of the vehicle loads A to E of the vehicle load 2a is operating, using switches that control the ON / OFF operation of the vehicle load 2a and current sensors that detect the current flowing through each load. Using the operational information acquired by the protection circuit 8, the load current can be estimated. For example, the minimum currents of loads A to E in the front zone of the vehicle shown in Figure 8 are stored in the switch control device 13 of the power distribution device 1a, and the test current switch 10a is opened or closed depending on whether the sum of the minimum load currents of the operating vehicle loads is less than or equal to the first threshold Ith1. It is also determined that the interruption element 7a is conducting and that load current is being supplied from the power main line 3a. The switch control device 13 can be configured using a microcomputer or the like.
[0045] For example, if the current threshold for detecting a broken wire is 100mA, then if only the drive recorder is operating, a broken wire will be detected unless a test current is applied. Therefore, the test current switch 10a is closed, and the test current is applied to the test current load 9a.
[0046] According to the fourth embodiment, if the power line 3a is functioning normally, a main line current IM of a predetermined value or higher can always be supplied, and a break in the wire can be determined by monitoring the detected current of the current detection element 6a. In other words, since the test current is controlled according to the operating state of the vehicle load 2a, a break in the wire can be determined by monitoring the detected current of the current detection elements 6a and 6b regardless of the operating state of the load.
[0047] As described above, with the power distribution device of this embodiment, a break in the circuit can be determined when the current flowing through the connected power trunk is zero or below a predetermined threshold. Therefore, even while driving, a break in the on-board power network can be detected in a short time without interrupting the power supply, and the location of the break can also be identified.
[0048] Furthermore, since the test current switches 10a and 10b are controlled according to the operating state of the vehicle load 2a, current consumption due to the test current can be suppressed.
[0049] It should be noted that the present invention is not limited to the embodiments described above, but includes various modifications and equivalent configurations within the spirit of the attached claims. For example, the embodiments described above are described in detail to make the present invention easier to understand, and the present invention is not necessarily limited to having all of the described configurations. Furthermore, some of the configurations of one embodiment may be replaced with those of another embodiment. Furthermore, configurations of other embodiments may be added to the configuration of one embodiment. Furthermore, some of the configurations of each embodiment may be added, deleted, or replaced with those of other embodiments.
[0050] Furthermore, each of the aforementioned configurations, functions, processing units, and processing means may be implemented in hardware, for example, by designing them as integrated circuits, or they may be implemented in software by having a processor interpret and execute programs that realize each function.
[0051] Information such as programs, tables, and files that implement each function can be stored in memory, hard disks, SSDs (Solid State Drives), or other storage media such as IC cards, SD cards, and DVDs.
[0052] Furthermore, the control lines and information lines shown are those deemed necessary for explanation purposes and do not necessarily represent all control lines and information lines required for implementation. In reality, it can be assumed that almost all components are interconnected. [Explanation of Symbols]
[0053] 1a~1d…Power distribution device 2…Vehicle load 3a~3f…Power main line 4…Battery 5…DC / DC converter 6a, 6b... Current sensing elements 7a, 7b... Blocking elements 8…Protection circuit 9a, 9b... Test current load 10a, 10b... Test current switch 11a...Current detection unit 12a...judgment section 13…Switch control unit
Claims
1. A power distribution device that supplies power to vehicle loads via two or more paths provided by power trunk lines, A current detection element for detecting the current in the power trunk line, The system includes an inspection current control unit that controls the amount of current flowing through paths other than the vehicle load according to the operating state of the vehicle load, The aforementioned inspection current control unit is When the current in the power main line falls below a first threshold, a predetermined test current is supplied to a path other than the vehicle load. If the current in the power line is less than a second threshold value which is set to a value less than the first threshold value, the power line is determined to be broken. When the predetermined test current flows through a path other than the vehicle load, the value of the first threshold is set higher than the value of the test current. A power distribution device characterized by setting the value of the test current to be higher than the value of the second threshold.
2. A power distribution device that supplies power to a vehicle load via two or more paths provided by a power trunk line, A current detection element for detecting the current in the power trunk line, The system includes an inspection current control unit that controls the amount of current flowing through paths other than the vehicle load according to the operating state of the vehicle load, The aforementioned inspection current control unit is When the current in the power main line falls below a first threshold, a predetermined test current is supplied to a path other than the vehicle load. When the vehicle is stopped, the inspection current is switched to a pulsed current. A power distribution device characterized in that, when the pulsed test current flows, if the current in the power line is less than a second threshold value which is set to a value less than the first threshold value, the power line is determined to be open.
3. A power distribution device that supplies power to a vehicle load via two or more paths provided by a power trunk line, A current detection element for detecting the current in the power trunk line, The system includes an inspection current control unit that controls the amount of current flowing through paths other than the vehicle load according to the operating state of the vehicle load, The aforementioned inspection current control unit is When the current in the power main line falls below a first threshold, a predetermined test current is supplied to a path other than the vehicle load. When the current in the power main line is greater than the first threshold, a predetermined current is supplied to a path other than the vehicle load. A power distribution device characterized by diagnosing a fault in the test current control unit by detecting a change in the main current flowing through the current detection element at the timing when a predetermined value of current flows.
4. A power distribution device according to any one of claims 1 to 3, The aforementioned inspection current control unit is The vehicle load has an inspection current load provided in a path other than the aforementioned vehicle load, A power distribution device characterized by controlling the amount of test current flowing to the test current load according to the operating state of the vehicle load.
5. A power distribution device according to claim 4, The power distribution device is characterized in that the test current control unit has a switch for opening and closing the current path to the test current load.
6. A power distribution device according to any one of claims 1 to 3, The inspection current control unit is a power distribution device characterized by controlling the current to flow to a path other than the vehicle load when the current flowing to the vehicle load is less than a predetermined threshold.
7. A method for determining a broken wire in a power distribution device, The power distribution device is Power is supplied through two or more paths via power trunk lines, and the supplied power is supplied to the vehicle load. A current detection element for detecting the current in the power trunk line, The system includes an inspection current control unit that controls the amount of current flowing through paths other than the vehicle load according to the operating state of the vehicle load, The method for determining wire breakage is The inspection current control unit, when the current in the power main line falls below a first threshold, flows a predetermined inspection current to a path other than the vehicle load. The inspection current control unit determines that the power line is broken if, while the predetermined inspection current is flowing, the current in the power line is less than a second threshold value which is set to a value less than the first threshold value. When the inspection current control unit has a predetermined inspection current flowing through a path other than the vehicle load, it sets the value of the first threshold higher than the value of the inspection current. A method for determining a broken wire, characterized in that the test current control unit sets the value of the test current higher than the value of the second threshold.
8. A method for determining a broken wire in a power distribution device, The power distribution device is Power is supplied through two or more paths via power trunk lines, and the supplied power is supplied to the vehicle load. A current detection element for detecting the current in the power trunk line, The system includes an inspection current control unit that controls the amount of current flowing through paths other than the vehicle load according to the operating state of the vehicle load, The method for determining wire breakage is The inspection current control unit, when the current in the power main line falls below a first threshold, flows a predetermined inspection current to a path other than the vehicle load. The inspection current control unit switches the inspection current to a pulsed current when the vehicle is stopped. A method for determining a power line break, characterized in that the inspection current control unit determines that the power line is broken when the current in the power line is less than a second threshold value set to a value less than the first threshold value when the pulsed inspection current flows.
9. A method for determining a broken wire in a power distribution device, The power distribution device is Power is supplied through two or more paths via power trunk lines, and the supplied power is supplied to the vehicle load. A current detection element for detecting the current in the power trunk line, The system includes an inspection current control unit that controls the amount of current flowing through paths other than the vehicle load according to the operating state of the vehicle load, The method for determining wire breakage is The inspection current control unit, when the current in the power main line falls below a first threshold, flows a predetermined inspection current to a path other than the vehicle load. The inspection current control unit, when the current of the power main line is greater than the first threshold, flows a predetermined value of current to a path other than the vehicle load. A method for determining a broken wire, characterized in that the inspection current control unit diagnoses a malfunction of the inspection current control unit based on a change in the main current flowing through the current detection element at the timing when a predetermined value of current flows.