Power diode fault detection method in specific power distribution system

Abstract

The invention discloses a power diode fault detection method in a specific power distribution system, and relates to the technical field of aviation power distribution. The invention relates to a power diode fault detection method in a specific direct current power distribution system, which does not need to additionally add a test circuit and realizes diode fault detection by using an inherent sensor in a specific power distribution system network. The method is applied to a complex specific power distribution system, fault identification of the power diode is realized by detecting voltage and current at two ends of the power diode under a complex power distribution network topology, and the method is used for identifying a short-circuit fault and an open-circuit fault of the diode.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation power distribution systems, and in particular relates to a power diode fault detection method in a specific power distribution system. Background Art

[0002] A specific power distribution system has many lines and load importance levels vary greatly. After a DC short circuit fault, the line current rises rapidly. If the fault is not isolated in time, it will endanger the safety of the equipment and even cause the entire system to crash, that is, a single point fault will endanger the entire network. In order to reduce the scope of the fault, a fast fault zoning method should be used to limit the fault to the fault area, ensure the power supply of the healthy area and the rapid recovery of the system after the fault. At present, the fault zoning method based on the unidirectional conduction characteristics of power diodes is widely used in specific power distribution systems. After a DC fault occurs, the fault area and the healthy area are automatically divided to limit the scope of the fault. However, during the long-term high-current operation of the power diode, the diode junction temperature may fluctuate frequently and greatly, accelerating its aging, and even causing open or short circuit faults. Therefore, it is very important to monitor the operating status of the power diode.

[0003] There are generally two methods for fault detection of diodes in current technology: 1. Off-site detection method, which removes the diode from the system to detect the fault mode; 2. Determine the fault mode of the diode by adding an additional circuit to inject a signal.

[0004] The traditional off-site detection method is only applicable to the regular power-off maintenance of the power distribution system, which affects the continuous power-off hours of the system. Moreover, if a fault occurs during the operation of the power distribution system, the power distribution control device cannot identify the fault point, causing the entire system to crash.

[0005] By adding an additional circuit to inject a signal to identify the diode failure mode, it is necessary to add a signal injection and conditioning circuit on the basis of the original system circuit. Although the diode failure mode can be accurately determined and the fault point can be reported to the power distribution control device, the signal injection and conditioning circuit requires the addition of large-scale devices to the original circuit, which increases the product manufacturing cost and reduces the product reliability. Summary of the invention

[0006] In order to solve the deficiencies of the above-mentioned prior art and to address the above-mentioned technical problems, the purpose of the present invention is to provide a power diode fault detection method for a specific power distribution system, and to locate open circuit and short circuit faults.

[0007] In view of this, according to one aspect of an embodiment of the present invention, a method for detecting a power diode fault in a specific power distribution system is provided. The power distribution system includes a plurality of power input bus bars, and the plurality of power input bus bars are voted to form a voting bus bar through corresponding power diodes. The plurality of power input bus bars and the voting bus bar respectively supply power to different loads. The diode fault detection steps are as follows:

[0008] Step 1: Periodically collect the current and voltage of each bus bar, and compare the sampled voltage and current with the preset fault voltage and current. If the sampled voltage and current values ​​meet the fault threshold conditions, start counting;

[0009] Step 2: Continue to sample the voltage and current within the set count setting value range, and compare the sampling results with the preset fault voltage and current values;

[0010] Step 3: Within the set count setting value range, count the number of times the sampled voltage and current values ​​meet the fault threshold conditions. If the count is greater than the set value, it is determined that the diode to be tested is faulty; if not, the count is reset and counted again.

[0011] Optionally, the fault threshold includes a fault current threshold and a fault voltage threshold; the fault current threshold includes a short circuit fault current threshold and an open circuit fault current threshold; the fault voltage threshold includes a short circuit fault voltage threshold and an open circuit fault voltage threshold; the diode fault includes a diode open circuit fault and a diode short circuit fault; the count is the number of sampling times, which is compared with a set value; the diode fault to be tested includes a short circuit fault confirmation value and an open circuit fault confirmation value.

[0012] Optionally, after the electrical system identifies an open circuit or short circuit fault of a power diode, it reports fault information based on the fault point and isolates the fault circuit by controlling a contactor.

[0013] Optionally, preset fault current and voltage thresholds are set according to different scenarios.

[0014] Optionally, the voltage and current signals are sampled at time intervals of tens of milliseconds, and the sampled voltage and current values ​​are compared with the fault thresholds. If the preset conditions are met, the timing is started. If the fault is triggered continuously within hundreds of milliseconds, the fault flag is reported, otherwise the timing is terminated.

[0015] Optionally, a diode short circuit fault identification method is also included:

[0016] Step 1: variable initialization, initializing the diode current, the voting bus E voltage and the voltage of one of the power input bus A, bus A and bus B generate voting bus E;

[0017] Step 2: Connect another power input bus bar B and disconnect bus bar A;

[0018] Step 3: Periodically sample and vote on the bus voltage, bus A voltage, and the current of the power diode A1 corresponding to bus A;

[0019] Step 4: When the power distribution control system determines that the bus E voltage is greater than the preset threshold, the bus A voltage is greater than the preset threshold, and the power diode A1 current is less than the threshold, it is determined that the power diode A1 has a short circuit fault, that is, the power diode is reversely conducting.

[0020] Optionally, include a diode open fault identification method:

[0021] Step 1: Initialize variables, initialize bus A, bus B, current IA of diode A1 corresponding to bus A, current IB of diode B1 corresponding to bus B, where bus A and bus B generate voting bus E;

[0022] Step 2: Connect bus bar A, connect bus bar A and bus bar B, and disconnect bus bar B;

[0023] Step 3: Periodically sample the values ​​of bus A voltage, bus B voltage, bus E voltage, diode A1 current IA, and diode B1 current IB;

[0024] Step 4: When the voltages of busbars A and B in the power distribution system are the same, IA < short-circuit threshold and IB > open-circuit threshold, it can be determined that power diode A1 has an open-circuit fault.

[0025] The present invention adopts the above technical solution, which has the following beneficial effects:

[0026] 1. Use the existing voltage and current sampling signals in the power distribution system without adding additional sampling circuits to reduce costs.

[0027] 2. A specific distribution network topology is formed by controlling the contactor. Under a specific distribution network topology, the open circuit and short circuit characteristics of the diode are used to detect the fault mode. The specific distribution network structure should be able to ensure that the important bus loads with high levels of power are not powered off, avoiding the power outage of important loads during the fault detection process. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is the schematic diagram of the power distribution control device and the power distribution system structure;

[0029] Figure 2 The present invention is a flowchart for determining a power diode fault using the method of the present invention. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] According to one aspect of an embodiment of the present invention, a method for detecting power diode faults in a specific power distribution system is provided, wherein the power distribution system includes a plurality of power input bus bars, and the plurality of power input bus bars are voted through corresponding power diodes to form a voting bus bar, and the plurality of power input bus bars and the voting bus bars respectively supply power to different loads. In a power diode fault detection scenario in a specific power distribution system, the power distribution system includes a plurality of power input bus bars (the number of bus bars is greater than or equal to 2, and a dual-power supply three-28V bus bar distribution system is used as an example), the dual power supplies are power supply A and power supply B, power supply A and bus bar A are connected through a contactor (close contactor Ka, power supply A can supply power to bus bar A), power supply B and bus bar B are connected through contactor Kb (close contactor Kb, power supply B can supply power to bus bar B), and contactor Kd is connected between bus bar A and bus bar B. Bus bar A and bus bar B are voted through corresponding power diodes to form a voting bus bar, that is, bus bar A and bus bar B are voted through corresponding power diodes to form a voting bus bar, that is, bus bar B. Bus A and bus B vote to form bus E, the power diode connected to bus A is A1, and the power diode connected to bus B is B1. Buses A, B, and E supply power to different loads respectively. At the same time, the power distribution system has the function of voltage and current collection. It can collect the current and voltage of each bus without adding any additional sampling circuits to obtain UA, UB, UE, IA, and IB. It can be concluded that the positive and negative voltages of power diode A are UA and UE respectively, and the current IA flowing through diode A; the positive and negative voltages of power diode B are UB and UE respectively, and the current IB flowing through diode B.

[0032] The steps for diode fault detection are:

[0033] Step 1: Periodically collect the current and voltage of each bus bar, and compare the sampled voltage and current with the preset fault voltage and current. If the sampled voltage and current values ​​meet the fault threshold conditions, start counting;

[0034] Step 2: Continue to sample the voltage and current within the set count setting value range, and compare the sampling results with the preset fault voltage and current values;

[0035] Step 3: Within the set count setting value range, count the number of times the sampled voltage and current values ​​meet the fault threshold conditions. If the count is greater than the set value, it is determined that the diode to be tested is faulty; if not, the count is reset and counted again.

[0036] The present invention judges two failure modes of power diodes in a specific power distribution system. The first failure mode is to judge whether the diode has a short circuit failure; the second failure mode is to judge whether the diode has an open circuit failure. By controlling the power distribution system to work in a specific network topology, it is judged whether the power diode is in a short circuit or open circuit failure mode based on the voltage and current at both ends of the power diode.

[0037] The present invention combines the network topology of a specific power distribution system, collects the terminal voltage and loop current of the power diode, determines the fault mode of the power diode, and reports the fault to the power distribution control device, so that the system can correctly isolate the fault area. The present invention solves the risk of power diode failure in a specific power distribution system by combining software and hardware.

[0038] Furthermore, the fault threshold includes a fault current threshold and a fault voltage threshold; the fault current threshold includes a short-circuit fault current threshold and an open-circuit fault current threshold; the fault voltage threshold includes a short-circuit fault voltage threshold and an open-circuit fault voltage threshold; the diode fault includes a diode open-circuit fault and a diode short-circuit fault; the count is the number of samplings, which is compared with a set value; the diode fault to be tested includes a short-circuit fault confirmation value and an open-circuit fault confirmation value.

[0039] Furthermore, after the electrical system identifies an open circuit or short circuit fault of a power diode, it reports fault information according to the fault point and isolates the fault circuit by controlling the contactor.

[0040] Furthermore, preset fault current and voltage thresholds are set according to different scenarios. The preset fault current and voltage thresholds are adjustable and can be set according to different scenarios to prevent misjudgment.

[0041] Furthermore, the voltage and current signals are sampled at time intervals of tens of milliseconds, and the sampled voltage and current values ​​are compared with the fault thresholds. If the preset conditions are met, the timing is started. If the fault is triggered continuously within hundreds of milliseconds, the fault flag is reported, otherwise the timing is terminated.

[0042] Furthermore, a diode short circuit fault identification method is also included:

[0043] Step 1: variable initialization, initializing the diode current, the voting bus E voltage and the voltage of one of the power input bus A, bus A and bus B generate voting bus E;

[0044] Step 2: Connect another power input bus bar B and disconnect bus bar A;

[0045] Step 3: Periodically sample and vote on the bus voltage, bus A voltage, and the current of the power diode A1 corresponding to bus A;

[0046] Step 4: When the power distribution control system determines that the bus E voltage is greater than the preset threshold, the bus A voltage is greater than the preset threshold, and the power diode A1 current is less than the threshold, it is determined that the power diode A1 has a short circuit fault, that is, the power diode is reversely conducting.

[0047] Furthermore, a diode open circuit fault identification method is included:

[0048] Step 1: Initialize variables, initialize bus A, bus B, current IA of diode A1 corresponding to bus A, current IB of diode B1 corresponding to bus B, where bus A and bus B generate voting bus E;

[0049] Step 2: Connect bus bar A, connect bus bar A and bus bar B, and disconnect bus bar B;

[0050] Step 3: Periodically sample the values ​​of bus A voltage, bus B voltage, bus E voltage, diode A1 current IA, and diode B1 current IB;

[0051] Step 4: When the voltages of busbars A and B in the power distribution system are the same, IA < short-circuit threshold and IB > open-circuit threshold, it can be determined that power diode A1 has an open-circuit fault.

[0052] Example 1

[0053] A fault detection scenario of a power diode in a specific power distribution system is characterized in that: the power distribution system includes multiple power input bus bars (the number of bus bars is greater than or equal to 2, and a dual-power three-28V bus bar distribution system is used as an example), the dual power supplies are power supply A and power supply B, power supply A and bus bar A are connected through a contactor (close contactor Ka, power supply A can supply power to bus bar A), power supply B and bus bar B are connected through contactor Kb (close contactor Kb, power supply B can supply power to bus bar B), contactor Kd is connected between bus bar A and bus bar B, and bus bar A and bus bar B vote through corresponding power diodes to form a voting bus bar, That is, bus A and bus B vote to form bus E, the power diode connected to bus A is A1, and the power diode connected to bus B is B1. Buses A, B, and E supply power to different loads respectively. At the same time, the power distribution system has the function of voltage and current collection. It can collect the current and voltage of each bus without adding any additional sampling circuits to obtain UA, UB, UE, IA, and IB. It can be concluded that the positive and negative voltages of power diode A are UA and UE respectively, and the current flowing through diode A is IA; the positive and negative voltages of power diode B are UB and UE respectively, and the current flowing through diode B is IB.

[0054] The steps for diode fault detection are roughly as follows:

[0055] Step 1: Perform AD sampling of the voltage and current periodically, and compare the sampled voltage and current with the preset fault voltage and current. If the sampled voltage and current values ​​meet the fault threshold conditions, start counting;

[0056] Step 2: Continue to sample the voltage and current within the set count setting value range, and compare the sampling results with the preset fault voltage and current values;

[0057] Step 3: Within the set count setting value range, count the number of times the sampled voltage and current values ​​meet the fault threshold conditions. If the count is greater than the set value, it is determined that the diode to be tested is faulty; if not, the count is reset and counted again.

[0058] The fault threshold includes a fault current threshold and a fault voltage threshold; the fault current threshold includes a short circuit fault current threshold and an open circuit fault current threshold; the fault voltage threshold includes a short circuit fault voltage threshold and an open circuit fault voltage threshold; the diode fault includes a diode open circuit fault and a diode short circuit fault; the count is the number of sampling times, which is compared with the set value; the diode fault to be tested includes a short circuit fault confirmation value and an open circuit fault confirmation value.

[0059] After the power distribution system identifies the open circuit or short circuit fault of the power diode, it can report the fault information according to the fault point and accurately isolate the fault circuit by controlling the contactor;

[0060] The preset fault current and voltage thresholds are adjustable and can be set according to different scenarios to prevent misjudgment;

[0061] The power distribution control device samples the voltage and current signals at intervals of tens of milliseconds, and compares the sampled voltage and current values ​​with the fault thresholds. If the preset conditions are met, the timing is started. If the timing is started and the fault is continuously triggered within hundreds of milliseconds, the fault flag is reported, otherwise the timing is terminated.

[0062] Short circuit fault identification mode:

[0063] Step 1: Initialize variables, initialize diode A1 current, bus A voltage, and bus E voltage;

[0064] Step 2: Control the state of the power contactor, close contactor Kb, and open contactors Ka and Kd;

[0065] Step 3: Periodically sample the bus bar E voltage, bus bar A voltage, and power diode IA values;

[0066] Step 4: When the power distribution control system determines that the voltage of busbar E is greater than 15V, the voltage of busbar A is greater than 10V, and the current IA of power diode A1 is less than -1A, it is determined that power diode A1 has a short circuit fault, that is, the power diode is reversely conducting. If the above judgment conditions are not met, it is determined that diode A1 has not a short circuit fault.

[0067] Open circuit fault identification mode:

[0068] Step 1: Initialize variables, initialize bus A, bus B, diode current IA, diode current IB;

[0069] Step 2: Control the state of the power contactor, close contactor Ka and contactor Kd, and open contactor Kb;

[0070] Step 3: Periodically sample the values ​​of bus A voltage, bus B voltage, bus E voltage, diode A1 current IA, and diode B1 current IB;

[0071] Step 4: When the power distribution control system determines that the voltage of bus E is greater than 15V, the voltage of bus A is greater than 10V, and the current IA of power diode A1 is less than -1A, it is determined that power diode A1 has a short circuit fault, that is, the power diode is reversely conducting. If the above judgment conditions are not met, it is determined that diode A1 has not had a short circuit fault. When the voltages of buses A and B in the power distribution system are the same, IA<1A and IB>3A, it can be determined that power diode A1 has an open circuit fault. If the above judgment conditions are not met, it can be determined that diode A1 has not had an open circuit fault in this mode.

[0072] Example 2

[0073] The present invention judges two failure modes of power diodes in a specific power distribution system. The first failure mode is to judge whether the diode has a short circuit failure; the second failure mode is to judge whether the diode has an open circuit failure. By controlling the power distribution system to work in a specific network topology, it is judged whether the power diode is in a short circuit or open circuit failure mode based on the voltage and current at both ends of the power diode.

[0074] The present invention combines the network topology of a specific power distribution system, collects the terminal voltage and loop current of the power diode, determines the fault mode of the power diode, and reports the fault to the power distribution control device, so that the system can correctly isolate the fault area. The present invention solves the risk of power diode failure in a specific power distribution system by combining software and hardware.

[0075] A method for detecting a fault of a power diode in a specific power distribution system, characterized in that:

[0076] (1) The power distribution control device outputs a control signal to control the contactor switch state to form a specific power distribution network topology, and performs diode fault detection based on the voltage and current signals sampled based on the current network topology.

[0077] (2) Presetting diode fault determination parameters, including fault current threshold, fault voltage threshold, fault confirmation value and delay confirmation time. The fault current threshold includes short-circuit fault current threshold and open-circuit fault current threshold; the fault voltage threshold includes short-circuit fault voltage threshold and open-circuit fault voltage threshold; the fault confirmation value includes short-circuit fault confirmation value and open-circuit fault confirmation value;

[0078] (3) The voltage and current are sampled periodically by the power distribution control device, and the sampled voltage and current are compared with the preset fault voltage and current. If the sampled voltage and current values ​​meet the fault threshold conditions, the timer is started to start timing;

[0079] (4) Within the set delay confirmation time, continue to sample the voltage and current at the preset time intervals, and compare the sampling results with the preset fault value. If the short circuit or open circuit fault confirmation value continues to be true within the set delay confirmation time, a permanent open circuit or short circuit fault alarm is reported, otherwise the timing is terminated and the open circuit or short circuit fault flag is cleared.

[0080] (5) After the power distribution system identifies the open circuit or short circuit fault of the power diode, it can report the fault information according to the fault point and accurately isolate the fault circuit by controlling the contactor.

[0081] In the above method, in step (2), a specific distribution network topology is formed by controlling the contactor. Under the specific distribution network topology, the open circuit and short circuit characteristics of the diode are used to detect the fault mode. The specific distribution network structure should be able to ensure that the busbar load with high importance level is not powered off, avoiding the power failure of important loads during the fault detection process.

[0082] In the above method, in step (1), in order to reduce costs, no high-precision voltage and current sampling circuits are added. In step (3), in order to avoid the problem of poor accuracy in voltage and current signal acquisition in the power distribution network and to avoid false alarms of power diode faults, the preset fault current and fault voltage should have a certain margin.

[0083] In the above method, in step (5), the power distribution control device samples the voltage and current signals at a time interval of 10ms, and compares the sampled voltage and current values ​​with the fault threshold. If the preset conditions are met, the timing is started. Within 200ms of starting the timing, if the fault is continuously triggered, the fault flag is reported, otherwise the timing is terminated.

[0084] Example 3

[0085] like Figure 1 It is a schematic diagram of a specific power distribution system. The system is a three-power source and four-bus 28V power distribution system composed of dual DC power supplies and batteries (A and B are DC power supplies; C is a battery; E power supply is the power supply after A and B vote, E can charge C or be powered by C), wherein the importance level of C bus is level I; the importance level of E bus is level II; the importance level of A and B bus is level III, and the importance levels are ranked from high to low as I, II, and III. The present invention is combined with the power distribution system, and the power distribution control device collects voltage and current signals to realize power diode fault detection. The specific method is as follows, such as Figure 2 As shown:

[0086] (1) Short circuit fault identification mode

[0087] (2) Variable initialization: initializing diode current, A bus voltage, and E bus voltage.

[0088] (3) Control the state of the power contactor, close contactor Kb, and open contactors Ka and Kd;

[0089] (4) This operation can ensure that the loads carried by the Class I, II and part of the Class III distribution busbars are not disconnected.

[0090] (5) Periodically sampling the values ​​of bus E voltage, bus A voltage, and current IA;

[0091] (6) When the power distribution control system determines that the bus voltage E is greater than 15V, the bus voltage A is greater than 10V, and the current IA is less than -1A, it is determined that the power diode A1 has a short circuit fault, that is, the power diode is reversely conducting. If the above judgment conditions are not met, it is determined that the diode A1 has not a short circuit fault.

[0092] (7) The same as steps (2) to (5) can be used to identify whether the power diode B1 has a short circuit fault.

[0093] (8) Open circuit fault identification mode 1

[0094] (9) Variable initialization, initialization voltage A, voltage B, current IA, current IB

[0095] (10) Control the state of the power contactor, close contactor Ka and contactor Kd, and open contactor Kb. This operation can ensure that the loads carried by the Class I, Class II, and Class III distribution buses are not disconnected.

[0096] (11) Measure the values ​​of bus A voltage, bus B voltage, bus C voltage, current IA, and current IB

[0097] (12) When the voltages of busbars A and B in the power distribution system are the same, IA<1A and IB>3A, it can be determined that the power diode A1 has an open circuit fault. If the above judgment conditions are not met, it can be determined that the diode A1 has not an open circuit fault in this mode.

[0098] (13) The same as steps (8) to (11) can be used to identify whether the power diode B1 has an open circuit fault.

[0099] (14) Open circuit fault identification mode 2

[0100] (15) Variable initialization, initialization voltage A, voltage C, current IA

[0101] (16) Control the state of the power contactor and close contactor Ka and contactor Kc. This operation can ensure that the loads carried by level I, level II, and part of level III busbars are not disconnected.

[0102] (17) Measure the bus A voltage, bus C voltage, and current IA

[0103] (18) Considering the characteristics of the battery power supply in the power distribution system, the battery voltage is usually slightly lower than the external power supply voltage. When the bus UA>UB and IA<1A, IC>3A in the power distribution system, it can be determined that the A-phase power diode has an open circuit fault. If the above judgment conditions are not met, it can be determined in this mode that the power diode A1 has not had an open circuit fault.

[0104] Similar to steps (14) to (17), it is possible to identify whether the power diode B1 has an open circuit fault.

[0105] The above is only a specific embodiment of the present invention, and the present invention is described in detail. The unexplained part is a conventional technology. However, the protection scope of the present invention is not limited to this. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for detecting power diode faults in a specific power distribution system, characterized in that ,The power distribution system includes multiple power input busbars, and the multiple power input busbars are voted through corresponding ,power diodes to form a voting busbar. Multiple power input busbars and the voting busbar ,supply power to different loads respectively. The diode fault detection steps are: Step 1: Periodically collect the current and voltage of each bus bar, and compare the sampled voltage and current with the preset fault voltage and current. If the sampled voltage and current values ​​meet the fault threshold conditions, start counting; Step 2: Continue to sample the voltage and current within the set count setting value range, and compare the sampling results with the preset fault voltage and current values; Step 3: Within the set count setting value range, count the number of times the sampled voltage and current values ​​meet the fault threshold conditions. If the count is greater than the set value, it is determined that the diode to be tested is faulty; if not, the count is reset and counted again.

2. The method according to claim 1, characterized in that The fault threshold includes a fault current threshold and a fault voltage threshold; the fault current threshold includes a short-circuit fault current threshold and an open-circuit fault current threshold; the fault voltage threshold includes a short-circuit fault voltage threshold and an open-circuit fault voltage threshold; the diode fault includes a diode open-circuit fault and a diode short-circuit fault; the count is the number of samplings, which is compared with the set value; the diode fault to be tested includes a short-circuit fault confirmation value and an open-circuit fault confirmation value.

3. The method according to claim 1, characterized in that After the power distribution system identifies the open circuit or short circuit fault of the power diode, it reports the fault information according to the fault point and isolates the fault circuit by controlling the contactor.

4. The method according to claim 1, characterized in that The preset fault current and voltage thresholds are set according to different scenarios.

5. The method according to claim 1, characterized in that The voltage and current signals are sampled at intervals of tens of milliseconds, and the sampled voltage and current values ​​are compared with the fault thresholds. If the preset conditions are met, the timing is started. If the fault is triggered continuously within hundreds of milliseconds, the fault flag is reported, otherwise the timing is terminated.

6. The method according to claim 1, characterized in that Also includes diode short circuit fault identification method: Step 1: variable initialization, initializing the diode current, the voting bus E voltage and the voltage of one of the power input bus A, bus A and bus B generate voting bus E; Step 2: Connect another power input bus bar B and disconnect bus bar A; Step 3: Periodically sample and vote on the bus voltage, bus A voltage, and the current of the power diode A1 corresponding to bus A; Step 4: When the power distribution control system determines that the bus E voltage is greater than the preset threshold, the bus A voltage is greater than the preset threshold, and the power diode A1 current is less than the threshold, it is determined that the power diode A1 has a short circuit fault, that is, the power diode is reversely conducting.

7. The method according to claim 1, characterized in that Also includes diode open circuit fault identification method: Step 1: Initialize variables, initialize bus A, bus B, current IA of diode A1 corresponding to bus A, current IB of diode B1 corresponding to bus B, where bus A and bus B generate voting bus E; Step 2: Connect bus bar A, connect bus bar A and bus bar B, and disconnect bus bar B; Step 3: Periodically sample the values ​​of bus A voltage, bus B voltage, bus E voltage, diode A1 current IA, and diode B1 current IB; Step 4: When the voltages of busbars A and B in the power distribution system are the same, IA < short-circuit threshold and IB > open-circuit threshold, it can be determined that power diode A1 has an open-circuit fault.

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