Commutation failure detection method, device, equipment, storage medium and program product

Abstract

This application relates to a commutation failure detection method, apparatus, device, storage medium, and program product. The method includes: first, identifying a target phase in a non-commutated state from the phases of the Y-bridge of a converter; then, detecting whether the Y-bridge meets a first commutation success condition; if the first commutation success condition is not met, identifying a first commutation failure valve group from the commutation valves included in each phase of the Y-bridge other than the target phase; if the first commutation success condition is met, detecting whether the D-bridge of the converter meets a second commutation success condition; finally, if the D-bridge does not meet the second commutation success condition, identifying a second commutation failure valve group from the commutation valves included in the D-bridge. This method can accurately locate the commutation failure valve, resulting in more accurate commutation failure detection.

Description

Technical Field

[0001] This application relates to the field of power system fault diagnosis technology, and in particular to a method, apparatus, equipment, storage medium, and program product for detecting commutation failure. Background Technology

[0002] Due to the advantages of conventional DC transmission, such as long transmission distance, large transmission capacity, and no power angle stability problem, a large number of power transmission projects using conventional DC transmission technology have been built in China in recent years. However, since the inverter stations of conventional DC transmission are prone to commutation failure due to factors such as AC system failures, it is crucial to detect the converter valve that has failed in the shortest possible time and take effective measures in a timely manner when commutation failure occurs in the DC transmission system to improve the stability of the DC system.

[0003] However, current methods for detecting commutation failure are not accurate enough. Summary of the Invention

[0004] Therefore, it is necessary to provide a method, apparatus, device, storage medium, and program product that can accurately detect commutation failure, addressing the aforementioned technical problems.

[0005] Firstly, this application provides a method for detecting commutation failure. The method includes:

[0006] The target phase in a non-commutation state is determined from each phase of the Y-bridge of the converter; it is checked whether the Y-bridge meets the first commutation success condition; if the first commutation success condition is not met, the first commutation failure valve group is determined from the commutation valves contained in each phase of the Y-bridge other than the target phase; if the first commutation success condition is met, it is checked whether the D-bridge of the converter meets the second commutation success condition, and if the second commutation success condition is not met, the second commutation failure valve group is determined from the commutation valves contained in the D-bridge.

[0007] In one embodiment, determining the target phase in a non-commutation state from the phases of the Y-bridge of the converter includes: acquiring the phase current of the Y-bridge; and determining the phase with positive current and satisfying a first current judgment condition as the target phase.

[0008] In one embodiment, detecting whether the Y-bridge meets the first commutation success condition includes: if the difference between the target phase current and the line current in the Y-bridge is less than a preset value, and the change rate of one phase current of the other two phase currents is positive and the change rate of the other phase current is negative, then it is determined that the Y-bridge meets the first commutation success condition.

[0009] In one embodiment, determining the first commutation failure group from the commutation valves contained in each phase of the Y-bridge other than the target phase includes: determining the commutation valves on the lower arms of the two phases of the Y-bridge other than the target phase as the first commutation failure group.

[0010] In one embodiment, detecting whether the D-bridge of the converter meets the second commutation success condition includes: if the difference between the target phase current and the line current in the D-bridge is less than a preset value, and the rate of change of one phase current of the other two phase currents is positive and the rate of change of the other phase current is negative, then it is determined that the D-bridge meets the second commutation success condition.

[0011] In one embodiment, determining the second commutation valve group that has failed from the commutation valves included in the D-bridge includes: determining the commutation valves on the lower arms of the two phases other than the target phase in the D-bridge as the second commutation valve group that has failed.

[0012] In one embodiment, determining the target phase in a non-commutation state from the phases of the Y-bridge of the converter includes: acquiring the phase current of the Y-bridge; and determining the phase with a negative phase current and satisfying a first current judgment condition as the target phase.

[0013] In one embodiment, detecting whether the Y-bridge meets the first commutation success condition includes: if the sum of the target phase current and the line current in the Y-bridge is less than a preset value, and the change rate of one phase current of the other two phase currents is positive and the change rate of the other phase current is negative, then it is determined that the Y-bridge meets the first commutation success condition.

[0014] In one embodiment, determining the first commutation failure group from the commutation valves contained in each phase of the Y-bridge other than the target phase includes: determining the commutation valves on the upper arms of the two phases of the Y-bridge other than the target phase as the first commutation failure group.

[0015] In one embodiment, detecting whether the D-bridge of the converter meets the second commutation success condition includes: if the sum of the target phase current and the line current in the D-bridge is less than a preset value, and the rate of change of one phase current of the other two phase currents is positive and the rate of change of the other phase current is negative, then it is determined that the D-bridge meets the second commutation success condition.

[0016] In one embodiment, determining the second commutation valve group that has failed from the commutation valves included in the D-bridge includes: determining the commutation valves on the upper arms of the two phases other than the target phase in the D-bridge as the second commutation valve group that has failed.

[0017] In one embodiment, the method further includes: acquiring the commutation angle; determining, based on the commutation angle, a delay time before detecting whether the Y-bridge meets the first commutation success condition, and a delay time before detecting whether the D-bridge of the converter meets the second commutation success condition.

[0018] In one embodiment, obtaining the commutation angle includes: obtaining the line current of the converter, the turn-off angle, the commutation line voltage on the valve side of the converter transformer connected to the converter, and the commutation reactance; and calculating the commutation angle based on the line current, the turn-off angle, the commutation line voltage, and the commutation reactance.

[0019] In one embodiment, the first current determination condition is that, among the phase currents, the difference between one phase current and the line current is less than a preset value, and the sum of one phase current and the line current of the other two phase currents is less than a preset value, and the other phase current is less than a preset value.

[0020] Secondly, this application also provides a commutation failure detection device. The device includes:

[0021] The first determining module is used to determine the target phase that is in a non-commutation state from each phase of the Y-bridge of the converter;

[0022] The detection module is used to detect whether the Y-bridge meets the conditions for successful first commutation;

[0023] The second determining module is used to determine the first commutation failure group from the commutation valves contained in each phase of the Y-bridge other than the target phase if the first commutation success condition is not met.

[0024] The third determining module is used to detect whether the D-bridge of the converter meets the second commutation success condition if the first commutation success condition is met, and to determine the second commutation valve group that failed to commutate from the commutation valves contained in the D-bridge if the second commutation success condition is not met.

[0025] In one embodiment, the first determining module is used to obtain the phase current of the Y-bridge; and to determine the phase with positive current and satisfying the first current judgment condition as the target phase.

[0026] In one embodiment, the detection module is specifically used to determine that the Y-bridge meets the first commutation success condition if the difference between the target phase current and the line current in the Y-bridge is less than a preset value, and the change rate of one phase current of the other two phase currents is positive and the change rate of the other phase current is negative.

[0027] In one embodiment, the second determining module is specifically used to determine that the commutator valves on the lower arms of the two phases other than the target phase in the Y-bridge are the first commutator valve group that failed to commutate.

[0028] In one embodiment, the third determining module is specifically used to determine that the D-bridge meets the second commutation success condition if the difference between the target phase current and the line current in the D-bridge is less than a preset value, and the change rate of one phase current of the other two phase currents is positive and the change rate of the other phase current is negative.

[0029] In one embodiment, the third determining module is specifically used to determine that the commutator valves on the lower arms of the two phases other than the target phase in the D bridge are the second commutator valve group that failed to commutate.

[0030] In one embodiment, the first determining module is specifically used to obtain the phase current of the Y bridge; and to determine the phase with a negative phase current and satisfying the first current judgment condition as the target phase.

[0031] In one embodiment, the detection module is specifically used to determine that the Y-bridge meets the first commutation success condition if the sum of the target phase current and the line current in the Y-bridge is less than a preset value, and the change rate of one phase current of the other two phase currents is positive and the change rate of the other phase current is negative.

[0032] In one embodiment, the second determining module is specifically used to determine that the converter valves on the upper arms of the two phases other than the target phase in the Y-bridge are the first converter valve group that failed to commutate.

[0033] In one embodiment, the third determining module is specifically used to determine that the D-bridge meets the second commutation success condition if the sum of the target phase current and the line current in the D-bridge is less than a preset value, and the change rate of one phase current of the other two phase currents is positive and the change rate of the other phase current is negative.

[0034] In one embodiment, the third determining module is specifically used to determine that the converter valves on the upper arms of the two phases other than the target phase in the D bridge are the second converter valve group that failed to commutate.

[0035] In one embodiment, a fourth determining module is further included, which is used to obtain the commutation angle; determine, based on the commutation angle, the delay time before detecting whether the Y-bridge meets the first commutation success condition, and the delay time before detecting whether the D-bridge of the converter meets the second commutation success condition.

[0036] In one embodiment, the fourth determining module is specifically used to obtain the line current, turn-off angle, commutation line voltage on the valve side of the converter transformer connected to the converter, and commutation reactance of the converter; and to calculate the commutation angle based on the line current, turn-off angle, commutation line voltage, and commutation reactance.

[0037] In one embodiment, the first current determination condition is that, among the phase currents, the difference between one phase current and the line current is less than a preset value, and the sum of one phase current and the line current of the other two phase currents is less than a preset value, and the other phase current is less than a preset value.

[0038] Thirdly, this application also provides a computer device. The computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the aforementioned commutation failure detection method.

[0039] Fourthly, this application also provides a computer-readable storage medium. This computer-readable storage medium stores a computer program thereon, which, when executed by a processor, implements the aforementioned commutation failure detection method.

[0040] Fifthly, this application also provides a computer program product. This computer program product includes a computer program that, when executed by a processor, implements the aforementioned commutation failure detection method.

[0041] The aforementioned commutation failure detection method, apparatus, equipment, storage medium, and program product first determine the target phase in a non-commutation state from the phases of the Y-bridge of the converter. Then, it checks whether the Y-bridge meets the first commutation success condition. If the first commutation success condition is not met, it identifies the first commutation failure valve group from the commutation valves included in each phase of the Y-bridge other than the target phase. If the first commutation success condition is met, it checks whether the D-bridge of the converter meets the second commutation success condition. Finally, if the D-bridge does not meet the second commutation success condition, it identifies the second commutation failure valve group from the commutation valves included in the D-bridge. In this way, it determines whether the commutation valves of the Y-bridge meet the first commutation success condition. If successful, it continues to determine whether the commutation valves of the D-bridge meet the second commutation success condition, and so on. If no condition is met, the commutation failure valve can be precisely located, making commutation failure detection more accurate. Attached Figure Description

[0042] Figure 1 This is a flowchart illustrating a commutation failure detection method in one embodiment;

[0043] Figure 2 This is a schematic diagram showing the connection between the converter transformer and the converter valve in another embodiment;

[0044] Figure 3 Here is a commutation waveform diagram of the D-bridge converter valve in another embodiment;

[0045] Figure 4 This is a flowchart illustrating a commutation failure detection method in another embodiment;

[0046] Figure 5 This is a flowchart illustrating the commutation angle calculation in another embodiment;

[0047] Figure 6 This is a flowchart illustrating a commutation failure detection method in another embodiment;

[0048] Figure 7 This is a flowchart illustrating a commutation failure detection method in another embodiment;

[0049] Figure 8This is a flowchart illustrating a commutation failure detection method in another embodiment;

[0050] Figure 9 A flowchart of a commutation failure detection method in another embodiment;

[0051] Figure 10 This is a schematic diagram of the commutation failure detection electronic device in another embodiment;

[0052] Figure 11 This is a structural block diagram of a commutation failure detection device in another embodiment;

[0053] Figure 12 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0055] Due to the advantages of conventional DC transmission, such as long transmission distance, large transmission capacity, and no power angle stability issues, a large number of transmission projects using conventional DC transmission technology have been built in China in recent years. However, because inverter stations in conventional DC transmission are prone to commutation failure due to factors such as AC system faults, it is crucial to detect the converter valve that has failed in the shortest possible time and take timely and effective measures to improve the stability of the DC system when commutation failure occurs. However, current methods for detecting commutation failure are not accurate enough.

[0056] In view of this, the present application provides a commutation failure detection method. By determining whether the commutation valve of the Y-bridge meets the first commutation success condition, if successful, the method continues to determine whether the commutation valve of the D-bridge meets the second commutation success condition, and so on. If the conditions are not met, the commutation valve group that failed to commutate can be accurately located, making the commutation failure detection more accurate.

[0057] In one embodiment, such as Figure 1 As shown, a commutation failure detection method is provided. Taking the application of this method to an electronic device as an example, the method includes the following steps:

[0058] Step 101: Determine the target phase that is in a non-commutation state from each phase of the Y-bridge of the converter.

[0059] In DC transmission projects, the commonly used converter is the 12-pulse converter. The connection between the converter and the converter transformer is as follows: Figure 2As shown, the converter includes a Y-bridge and a D-bridge. The Y-bridge includes converter valves Y1, Y2, Y3, Y4, Y5, and Y6, and the D-bridge includes converter valves D1, D2, D3, D4, D5, and D6. The converter includes phases A, B, and C. During converter operation, the converter valves of the Y-bridge and D-bridge sequentially perform phase commutation, with the target phase being one of the three phases that is not in a commutation period.

[0060] Step 102: Check whether the Y-bridge meets the conditions for successful first commutation.

[0061] The first commutation success condition is used to characterize whether the Y-bridge commutation was successful, and is determined based on the current values ​​of each phase of the Y-bridge. A current measuring device is installed on the valve side of the converter transformer to collect the current, such as... Figure 2 The currents IYA, IYB, IYC, IDA, IDB, and IDC are defined as having their positive direction when the current flows from the converter valve into the converter transformer. The collected current values ​​can be used to detect whether the Y-bridge meets the first commutation success condition. Taking the D-bridge as an example, the converter valve commutation waveform over a period of time is as follows: Figure 3 As shown, the areas corresponding to dashed boxes a and b represent the valve current waveforms during non-commutation periods; the areas corresponding to dashed boxes c and d represent the valve current waveforms during commutation periods; and the area corresponding to dashed box e represents one scenario of commutation failure. If the current value collected by the Y-bridge satisfies either the condition in dashed box c or dashed box d, that is, the Y-bridge satisfies the first commutation success condition.

[0062] Step 103: If the first commutation success condition is not met, then determine the first commutation valve group that failed to commutate from the commutation valves contained in each phase of the Y-bridge other than the target phase.

[0063] If the Y-bridge does not meet the first commutation success condition, it means that the current commutation process of the Y-bridge has failed. Since the target phase is in a non-commutation period, the first commutation valve group that failed is determined based on the commutation valves in the other two phases.

[0064] Step 104: If the first commutation success condition is met, then check whether the D-bridge of the converter meets the second commutation success condition. If the second commutation success condition is not met, determine the second commutation valve group that failed to commutate from the commutation valves included in the D-bridge.

[0065] If the Y-bridge meets the first commutation success condition, it indicates that the current commutation process of the Y-bridge is successful. Since the Y-bridge and D-bridge commutate sequentially, the next bridge to need commutation is the D-bridge. Based on the current value collected by the D-bridge, it is determined whether the D-bridge current meets the second commutation success condition. The second commutation success condition is used to characterize whether the D-bridge has successfully commutated. If the D-bridge is found to not meet the second commutation success condition, the second commutator valve group in the D-bridge that failed to commutate is identified.

[0066] The aforementioned commutation failure detection method first identifies the target phase in a non-commutated state from the phases of the Y-bridge of the converter. Then, it checks whether the Y-bridge meets the first commutation success condition. If the first commutation success condition is not met, the first commutation failure valve group is identified from the commutation valves in all phases of the Y-bridge except the target phase. If the first commutation success condition is met, the second commutation success condition is checked from the D-bridge of the converter. Finally, if the D-bridge does not meet the second commutation success condition, the second commutation failure valve group is identified from the commutation valves in the D-bridge. In this way, it determines whether the Y-bridge commutation valves meet the first commutation success condition. If successful, it continues to determine whether the D-bridge commutation valves meet the second commutation success condition, and so on. If no condition is met, the commutation failure valve can be precisely located, making commutation failure detection more accurate.

[0067] In the embodiments of this application, the Y-bridge and D-bridge commutate sequentially, with a delay between each commutation before the next commutation. By calculating the commutation angle, the commutation time of the converter valve can be determined. The specific steps are as follows: Figure 4 As shown, it includes:

[0068] Step 401: Obtain the phase angle.

[0069] The calculation steps for the commutation angle are as follows: Figure 5 As shown, it includes:

[0070] Step 501: Obtain the line current, turn-off angle, valve-side commutation line voltage of the converter transformer connected to the converter, and commutation reactance of the converter.

[0071] Among them, the line current I of the converter is collected by a DC current acquisition device. L The turn-off angle collector collects the turn-off angle γ; the converter valve side voltage collector collects the commutation line voltage E on the converter transformer valve side; and the commutation reactance collector collects the commutation reactance X. r .

[0072] Step 502: Calculate the commutation angle based on the line current, turn-off angle, commutation line voltage, and commutation reactance.

[0073] The formula for calculating the commutation angle μ is shown in Formula 1:

[0074]

[0075] Step 402: Based on the commutation angle, determine the delay time before detecting whether the Y-bridge meets the first commutation success condition, and determine the delay time before detecting whether the D-bridge of the converter meets the second commutation success condition.

[0076] Optionally, the high-voltage direct current transmission system provides a commutation voltage with a 30° phase difference from the YY converter transformer through the YD converter transformer. Therefore, for example... Figure 2 For the converter with the Ynd1 connection group shown, the D bridge begins commutation 1.67ms (30°) after the Y bridge commutates. If the connection group is another type, the commutation interval of the converter valve can also be determined according to the connection group. That is, the commutation sequence of the converter shown in Figure 2 is Y1, D1, Y2, D2, Y3, D3 in sequence, with each commutation interval being 1.67ms (30°).

[0077] In the above embodiments, by calculating the commutation angle, the commutation time of the converter valve can be obtained, and detection can be performed at each commutation to obtain the converter valve that has failed to commutate accurately.

[0078] In one embodiment, determining the target phase of the converter includes two methods, wherein the steps of the first method are as follows: Figure 6 As shown, it includes:

[0079] Step 601: Obtain the phase current of the Y-bridge.

[0080] Please continue to refer to this. Figure 2 The current is collected by a current measuring device, and the phase currents of the Y-bridge are IYA, IYB and IYC.

[0081] Step 602: Determine the phase with positive current and satisfying the first current judgment condition as the target phase.

[0082] The first current judgment condition is that, among the currents of each phase, the difference between the current of one phase and the current of the line is less than a preset value, and the sum of the current of one phase and the current of the line of the other two phases is less than a preset value, and the current of the other phase is less than a preset value.

[0083] Optionally, the first current determination condition is as shown in Formula 2:

[0084]

[0085] Among them, I set This is a preset value, i.e., the current setting value, obtained by taking into account measurement errors and factors to avoid malfunctions. L This represents the line current, where X1, X2, and X3 represent the phase of one of the phases, I. X1 I X2 , and I X3 This represents the current in the three phases.

[0086] For example, if the IYA current collected in the previous step is positive, and X1 represents phase A, X2 represents phase B, and X3 represents phase C, and the above first current judgment condition is met, then phase A is determined to be the target phase.

[0087] In the embodiments of this application, after determining the target phase, it is detected whether the Y-bridge meets the first commutation success condition. If the Y-bridge does not meet the first commutation success condition, the first converter valve group that failed to commutate is determined.

[0088] according to Figure 3 As can be seen from the current waveform diagram, if the difference between the target phase current and the line current in the Y-bridge is less than the preset value, and the change rate of one phase current of the other two phase currents is positive while the change rate of the other phase current is negative, then the Y-bridge is determined to meet the first commutation success condition.

[0089] Optionally, the successful condition for the first commutation is determined according to Formula 3:

[0090]

[0091] For example, please continue to refer to Figure 2 Based on the phase currents of the Y-bridge collected in the previous step, which are IYA, IYB, and IYC, and with phase A identified as the target phase, X1 represents phase A, X2 represents phase B, and X3 represents phase C, i.e., I... X1 Indicates Y-bridge IYA, I X2 Indicates Y-bridge IYB, I X3 Let IYC represent the Y-bridge. If IYA, IYB, and IYC always satisfy Formula 3 above during the entire commutation time, then the commutation of the Y-bridge is considered successful.

[0092] The converter valves on the lower arms of the two phases other than the target phase in the Y-bridge are identified as the first converter valve group that failed to switch phase.

[0093] Among them, the target phase is the non-commutation state, with Figure 2 Taking the connection method as an example, the converter valves on the lower arms of the two phases other than the target phase are the next converter valves to perform commutation. If the Y-bridge is detected to not meet the first commutation success condition, it means that the converter valves on the lower arms of the two phases have failed to perform commutation this time. For example, if phase A is the target phase, it means that valve Y2 has successfully commutated to valve Y4. The current of valve Y4 has just reached the line current and is in the period from the next commutation of the Y-bridge, I X1 Indicates Y-bridge IYA, I X2 Indicates Y-bridge IYB, I X3 Let IYC represent the Y-bridge. Based on the commutation sequence of the Y-bridge and D-bridge, after 60° - μ, which is the commutation interval, valve Y5 receives a trigger pulse, and Y3 begins to commutate to Y5. During the entire commutation time μ, if IYA, IYB, and IYC do not meet the formula for the first successful commutation condition mentioned above, then it is determined that the commutation of the converter valves Y3Y5 on the lower arm of the Y-bridge, excluding the target phase A, has failed.

[0094] In one embodiment, if the Y-bridge meets the first commutation success condition, it is then detected whether the D-bridge of the converter meets the second commutation success condition. If the D-bridge does not meet the second commutation success condition, the second converter valve group that failed to commutate is identified.

[0095] If the difference between the target phase current and the line current in bridge D is less than the preset value, and the rate of change of one phase current of the other two phase currents is positive while the rate of change of the other phase current is negative, then bridge D is determined to meet the second commutation success condition.

[0096] Optionally, the condition for determining the success of the second commutation is the same as shown in Formula 3, but at this time I X1 I X2 and I X3 The represented currents are different. An example illustrating the successful second commutation condition of the D-bridge is provided below; please refer to [link / reference]. Figure 2 The phase currents of bridge D are IDA, IDB, and IDC, and phase A is determined as the target phase. X1 represents phase A, X2 represents phase B, and X3 represents phase C, i.e., I X1 Indicates D-bridge IDA, I X2 Indicates D-bridge IDB, I X3 Let IDC represent the D-bridge. If IDA, IDB, and IDC consistently satisfy Formula 3 above throughout the commutation time, then the D-bridge is considered to have successfully completed the commutation.

[0097] The converter valves on the lower arms of the two phases other than the target phase in bridge D were identified as the second converter valve group that failed to switch phase.

[0098] Among them, the target phase is the non-commutation state, with Figure 2 Taking the connection method as an example, the converter valves on the lower arms of the two phases other than the target phase are the next converter valves to perform commutation. If the D bridge is detected to not meet the first commutation success condition, it means that the converter valves on the lower arms of the two phases have failed to perform commutation this time. For example, if the above Y3Y5 commutation is successful, after 30°-μ angle, I X1 Indicates D-bridge IDA, I X2 Indicates D-bridge IDB, I X3 This indicates that when valves D5 and D3 in bridge D receive a trigger pulse, commutation begins from D3 to D5. If IDA, IDB, and IDC do not satisfy Formula 3 above during the entire commutation time μ, then the commutation of the converter valves D3 and D5 on the lower arm of bridge D, excluding the target phase A, is determined to have failed.

[0099] Optionally, a second method for determining the target phase of the converter is as follows: Figure 7 As shown, it includes:

[0100] Step 701: Obtain the phase current of the Y-bridge.

[0101] Please continue to refer to this. Figure 2The current is collected by a current measuring device, and the phase currents of the Y-bridge are IYA, IYB and IYC.

[0102] Step 702: Determine the phase with a negative phase current and that meets the first current judgment condition as the target phase.

[0103] Optionally, the first current judgment condition is the same as Formula 2 of the first current judgment condition in the first method described above, but in this case, I... X1 I X2 and I X3 The currents represented are different. If the IYA current collected in the previous step is negative, and X1 represents phase B, X2 represents phase A, and X3 represents phase C, and the first current judgment condition is met, then phase A is determined to be the target phase.

[0104] In one embodiment, detecting whether the Y-bridge meets the first commutation success condition includes: if the sum of the target phase current and the line current in the Y-bridge is less than a preset value, and the rate of change of one phase current of the other two phase currents is positive and the rate of change of the other phase current is negative, then it is determined that the Y-bridge meets the first commutation success condition.

[0105] Optionally, the IYA current is negative. In this case, the formula for the first commutation success is as follows:

[0106]

[0107] Please continue to refer to this. Figure 2 Based on the phase currents of the Y-bridge collected in the previous step, which are IYA, IYB, and IYC, and with phase A identified as the target phase, X1 represents phase B, X2 represents phase A, and X3 represents phase C, i.e., I... X1 Indicates Y-bridge IDB, I X2 Indicates Y-bridge IDA, I X3 If IYA, IYB, and IYC consistently satisfy Formula 4 above during the entire commutation time, then the commutation of the Y-bridge is considered successful.

[0108] The converter valves on the upper arms of the two phases other than the target phase in the Y-bridge are identified as the first converter valve group that failed to switch phase.

[0109] Among them, the target phase is the non-commutation state, with Figure 2 Taking the connection method as an example, the converter valves on the lower arms of the two phases other than the target phase are the next converter valves to perform commutation. If the Y-bridge is detected to not meet the first commutation success condition, it means that the converter valves on the lower arms of the two phases have failed to perform commutation this time. For example, if phase A is the target phase and the IYA current is negative, it means that valve Y5 has successfully commutated to valve Y1. The current of valve Y5 has just reached the line current and is in the period between the next commutation of the Y-bridge. X1 Indicates Y-bridge IYB, IX2 Indicates Y-bridge IYA, I X3 In the Y-bridge IYC, after passing through an angle of 60°-μ, valve Y2 receives a trigger pulse, and Y6 begins to commutate to Y2. During the entire commutation time μ, if IYA, IYB, and IYC do not satisfy the above formula 4, then it is determined that the commutation of the converter valve Y6Y2 on the upper arm of the Y-bridge, except for the target phase A, has failed.

[0110] In one embodiment, it is detected whether the D-bridge of the converter meets the second commutation success condition. If the sum of the target phase current and the line current in the D-bridge is less than a preset value, and the change rate of one phase current of the other two phase currents is positive and the change rate of the other phase current is negative, then it is determined that the D-bridge meets the second commutation success condition.

[0111] Optionally, the formula for the second commutation success condition is shown in Formula 4, but at this time I X1 I X2 and I X3 The currents represented are different. For example, please refer to [link / reference needed]. Figure 2 The phase currents of bridge D are IDA, IDB, and IDC, and phase A is determined as the target phase. X1 represents phase B, X2 represents phase A, and X3 represents phase C, i.e., I X1 Indicates D-bridge IDB, I X2 Indicates D-bridge IDA, I X3 Let IDC represent the D-bridge. If IDA, IDB, and IDC consistently satisfy Formula 4 above throughout the commutation time, then the D-bridge is considered to have successfully completed the commutation.

[0112] The converter valves on the upper arms of the two phases other than the target phase in bridge D were identified as the second converter valve group that failed to switch phases.

[0113] Among them, the target phase is the non-commutation state, with Figure 2 Taking the connection method as an example, the converter valves on the lower arms of the two phases other than the target phase are the next converter valves to perform commutation. If the D bridge is detected to not meet the first commutation success condition, it means that the converter valves on the lower arms of the two phases have failed to perform commutation this time. For example, if the above Y6Y2 commutation is successful, after 30°-μ angle, I X1 Indicates D-bridge IDB, I X2 Indicates D-bridge IDA, I X3 This indicates that when valves D2 and D6 of bridge D receive a trigger pulse, commutation begins from D6 to D2. If IDA, IDB, and IDC do not meet the formula for the first successful commutation condition mentioned above within the entire commutation time μ, then the commutation of the converter valves D6 and D2 on the upper arm of bridge D, excluding the target phase A, is determined to have failed.

[0114] In the embodiments of this application, please refer to Figure 8The flowchart illustrates a commutation failure detection method provided in an embodiment of this application, which includes the following steps:

[0115] Step 801: Obtain the line current, turn-off angle, commutation line voltage on the valve side of the converter transformer connected to the converter, and commutation reactance of the converter.

[0116] Step 802: Calculate the commutation angle based on the line current, turn-off angle, commutation line voltage, and commutation reactance.

[0117] Step 803: Determine the target phase that is in a non-commutation state from each phase of the Y-bridge of the converter.

[0118] Step 804: Based on the commutation angle, determine the delay time before detecting whether the Y-bridge meets the first commutation success condition, and determine the delay time before detecting whether the D-bridge of the converter meets the second commutation success condition.

[0119] Step 805: Check whether the Y-bridge meets the conditions for successful first commutation.

[0120] Step 806: If the first commutation success condition is not met, then determine the first commutation valve group that failed to commutate from the commutation valves contained in each phase of the Y-bridge other than the target phase.

[0121] Step 807: If the first commutation success condition is met, then check whether the D-bridge of the converter meets the second commutation success condition. If the second commutation success condition is not met, determine the second commutation valve group that failed to commutate from the commutation valves included in the D-bridge.

[0122] To facilitate readers' understanding of the technical solutions provided in the embodiments of this application, the commutation failure detection process of this application is illustrated below with examples. Please refer to... Figure 9 The specific steps are as follows:

[0123] (1) Determine whether the converter is unlocked.

[0124] (2) Real-time detection of the shut-off angle, converter valve side line voltage, line current and commutation reactance, and calculation of the commutation angle according to Formula 1.

[0125] (3) Obtain the currents on the converter transformer side, i.e. IYA, IYB, IYC, IDA, IDB, IDC, and determine which phase current in the Y-bridge is positive and the three phase currents satisfy Formula 2, or determine which phase current in the Y-bridge is negative and the three phase currents satisfy Formula 2.

[0126] (4) If phase A satisfies the condition, that is, phase A is the target phase, where the result in parentheses is the judgment result when the current of phase A is negative. The specific process is as described in the above embodiment.

[0127] (5) If phase B satisfies the condition, i.e., phase B is the target phase, similarly, if the valve-side current of phase B of the Y-bridge is positive and the Y-bridge IYA, IYB, and IYC satisfy formula 2, then it indicates that valve Y4 has successfully switched to valve Y6, and the current of valve Y6 has just reached the line current during the period from the next commutation of the Y-bridge, I X1 Indicates Y-bridge IYB, I X2 Indicates Y-bridge IYC, I X3 This represents the Y-bridge IYA. After a 60°-μ angle, valve Y1 receives a trigger pulse, and Y5 begins commutating to Y1. During the entire commutation time μ, if the three-phase currents of the Y-bridge consistently satisfy Formula 3, it indicates that Y5 has successfully commutated to Y1; otherwise, it indicates that commutation failed when Y5 attempted to commutate to Y1. After another 30°-μ angle, I... X1 Indicates D-bridge IDB, I X2 Indicates D-bridge IDC, I X3 This indicates that the D-bridge IDA is connected. When valve D1 receives a trigger pulse, D5 begins to commutate to D1. During the entire commutation time μ, if the three-phase current of the D-bridge always satisfies Formula 3, it means that D5 has successfully commutated to D1; otherwise, it means that commutation failed when D5 commutated to D1.

[0128] In another scenario, as shown in parentheses, if the current of phase B valve in the Y-bridge is negative and the three-phase currents of the Y-bridge satisfy Formula 2, it indicates that valve Y1 has successfully switched to valve Y3. During the period from the first commutation of the Y-bridge, when the current of valve Y3 just reaches the line current, I... X1 Indicates Y-bridge IYC, I X2 Indicates Y-bridge IYB, I X3 This represents the Y-bridge IYA. After a 60°-μ angle, valve Y4 receives a trigger pulse, and Y2 begins to commutate to Y4. During the entire commutation time μ, if the three-phase currents of the Y-bridge consistently satisfy Formula 4, it indicates that Y2 has successfully commutated to Y4; otherwise, it indicates that commutation failed during the transition from Y2 to Y4. After another 30°-μ angle, I... X1 Indicates D-bridge IDC, I X2 Indicates D-bridge IDB, I X3 This indicates that the D-bridge IDA is connected. When valve D4 receives a trigger pulse, D2 begins to commutate to D4. During the entire commutation time μ, if the three-phase current of the D-bridge always satisfies Formula 4, it means that D2 has successfully commutated to D4; otherwise, it means that commutation failed when D2 commutated to D4.

[0129] (6) If phase B satisfies the condition, i.e., phase B is the target phase, similarly, if the valve-side current of phase C of the Y-bridge is positive and the Y-bridge IYA, IYB, and IYC satisfy formula 2, then it indicates that valve Y6 has successfully switched to valve Y2, and the current of valve Y2 has just reached the line current during the period from the first commutation of the Y-bridge, I X1 Indicates Y-bridge IYC, I X2 Indicates Y-bridge IYA, I X3This represents the Y-bridge IYB. After a 60°-μ angle, valve Y3 receives a trigger pulse, and Y1 begins to commutate to Y3. During the entire commutation time μ, if the three-phase currents of the Y-bridge consistently satisfy Formula 3, it indicates that Y1 has successfully commutated to Y3; otherwise, it indicates that commutation failed during the transition from Y1 to Y3. After another 30°-μ angle, I... X1 Indicates D-bridge IDC, I X2 Indicates D-bridge IDA, I X3 This indicates that the D-bridge IDB is connected. When valve D3 receives a trigger pulse, D1 begins to commutate to D3. During the entire commutation time μ, if the three-phase current of the D-bridge always satisfies Formula 3, it means that D1 has successfully commutated to D3; otherwise, it means that commutation failed when D1 commutated to D3.

[0130] In another scenario, as shown in parentheses, if the current of phase C valve in the Y-bridge is negative and the three-phase currents of the Y-bridge satisfy Formula 2, it indicates that valve Y3 has successfully switched to valve Y5. The current of valve Y5 just reaches the line current during the period from the first commutation of the Y-bridge, I... X1 Indicates Y-bridge IYA, I X2 Indicates Y-bridge IYC, I X3 This represents the Y-bridge IYB. After a 60°-μ angle, valve Y6 receives a trigger pulse, and Y4 begins commutating to Y6. During the entire commutation time μ, if the three-phase currents of the Y-bridge consistently satisfy Formula 4, it indicates that Y4 has successfully commutated to Y6; otherwise, it indicates that commutation failed during the transition from Y4 to Y6. After another 30°-μ angle, I... X1 Indicates D-bridge IDA, I X2 Indicates D-bridge IDC, I X3 This indicates that the D-bridge IDB is connected. When valve D6 receives a trigger pulse, D4 ​​begins to commutate to D6. During the entire commutation time μ, if the three-phase current of the D-bridge always satisfies Formula 4, it means that D4 has successfully commutated to D6; otherwise, it means that commutation failed when D4 commutated to D6.

[0131] As can be seen from the above embodiments, the time intervals between the three phases where the Y valve current is positive or negative are sequentially 120° apart, and the time interval for judging commutation failure is 30°. When commutation occurs between any two valves, commutation failure detection is performed dynamically, meaning that any commutation failure can be detected quickly at any time.

[0132] In one embodiment, such as Figure 10 As shown, the electronic device used in the commutation failure detection method provided in this application embodiment consists of a signal acquisition unit, a logic operation unit, and a signal output unit. The signal acquisition unit acquires various signals required by the electronic device, and after being processed by the logic operation unit, it provides detailed information about the commutation valve that has experienced a commutation failure.

[0133] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0134] Based on the same inventive concept, this application also provides a commutation failure detection device for implementing the commutation failure detection method described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more embodiments of the commutation failure detection device provided below can be found in the limitations of the commutation failure detection method described above, and will not be repeated here.

[0135] In one embodiment, such as Figure 11 As shown, a commutation failure detection device 1100 is provided, comprising: a first determining module 1101, a detection module 1102, a second determining module 1103, and a third determining module 1104, wherein:

[0136] The first determining module 1101 is used to determine the target phase that is in a non-commutation state from each phase of the Y-bridge of the converter;

[0137] The detection module 1102 is used to detect whether the Y-bridge meets the conditions for successful first commutation.

[0138] The second determining module 1103 is used to determine the first commutation failure group from the commutation valves contained in each phase of the Y-bridge other than the target phase if the first commutation success condition is not met.

[0139] The third determining module 1104 is used to detect whether the D-bridge of the converter meets the second commutation success condition if the first commutation success condition is met, and to determine the second commutation valve group that failed to commutate from the commutation valves included in the D-bridge if the second commutation success condition is not met.

[0140] In one embodiment, the first determining module 1101 is used to obtain the phase current of the Y bridge; and to determine the phase with positive current and satisfying the first current judgment condition as the target phase.

[0141] In one embodiment, the detection module 1102 is specifically used to determine that the Y-bridge meets the first commutation success condition if the difference between the target phase current and the line current in the Y-bridge is less than a preset value, and the change rate of one phase current of the other two phase currents is positive and the change rate of the other phase current is negative.

[0142] In one embodiment, the second determining module 1103 is specifically used to determine that the commutator valves on the lower arms of the two phases other than the target phase in the Y-bridge are the first commutator valve group that failed to commutate.

[0143] In one embodiment, the third determining module 1104 is specifically used to determine that the D-bridge meets the second commutation success condition if the difference between the target phase current and the line current in the D-bridge is less than a preset value, and the change rate of one phase current of the other two phase currents is positive and the change rate of the other phase current is negative.

[0144] In one embodiment, the third determining module 1104 is specifically used to determine that the commutator valves on the lower arms of the two phases other than the target phase in the D bridge are the second commutator valve group that failed to commutate.

[0145] In one embodiment, the first determining module 1101 is specifically used to obtain the phase current of the Y bridge; and to determine the phase with negative phase current and satisfying the first current judgment condition as the target phase.

[0146] In one embodiment, the detection module 1102 is specifically used to determine that the Y-bridge meets the first commutation success condition if the sum of the target phase current and the line current in the Y-bridge is less than a preset value, and the change rate of one phase current of the other two phase currents is positive and the change rate of the other phase current is negative.

[0147] In one embodiment, the second determining module 1103 is specifically used to determine that the commutator valves on the upper arms of the two phases other than the target phase in the Y-bridge are the first commutator valve group that failed to commutate.

[0148] In one embodiment, the third determining module 1104 is specifically used to determine that the D-bridge meets the second commutation success condition if the sum of the target phase current and the line current in the D-bridge is less than a preset value, and the change rate of one phase current of the other two phase currents is positive and the change rate of the other phase current is negative.

[0149] In one embodiment, the third determining module 1104 is specifically used to determine that the commutator valves on the upper arms of the two phases other than the target phase in the D bridge are the second commutator valve group that failed to commutate.

[0150] In one embodiment, a fourth determining module is further included, which is used to obtain the commutation angle; determine, based on the commutation angle, the delay time before detecting whether the Y-bridge meets the first commutation success condition, and the delay time before detecting whether the D-bridge of the converter meets the second commutation success condition.

[0151] In one embodiment, the fourth determining module is specifically used to obtain the line current, turn-off angle, commutation line voltage on the valve side of the converter transformer connected to the converter, and commutation reactance of the converter; and to calculate the commutation angle based on the line current, turn-off angle, commutation line voltage, and commutation reactance.

[0152] In one embodiment, the first current determination condition is that, among the phase currents, the difference between one phase current and the line current is less than a preset value, and the sum of one phase current and the line current of the other two phase currents is less than a preset value, and the other phase current is less than a preset value.

[0153] Each module in the aforementioned commutation failure detection device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0154] In one embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 12 As shown, the computer device includes a processor, memory, and a network interface connected via a system bus. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The database stores commutation data. The network interface communicates with external terminals via a network connection. When executed by the processor, the computer program implements a commutation failure detection method.

[0155] Those skilled in the art will understand that Figure 12 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0156] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to perform the following steps:

[0157] The target phase in a non-commutation state is determined from each phase of the Y-bridge of the converter; it is checked whether the Y-bridge meets the first commutation success condition; if the first commutation success condition is not met, the first commutation failure valve group is determined from the commutation valves contained in each phase of the Y-bridge other than the target phase; if the first commutation success condition is met, it is checked whether the D-bridge of the converter meets the second commutation success condition, and if the second commutation success condition is not met, the second commutation failure valve group is determined from the commutation valves contained in the D-bridge.

[0158] In one embodiment, when the processor executes the computer program, it further performs the following steps: acquiring the phase current of each phase of the Y-bridge; and identifying the phase with positive current and satisfying the first current judgment condition as the target phase.

[0159] In one embodiment, when the processor executes the computer program, it further implements the following steps: if the difference between the target phase current and the line current in the Y-bridge is less than a preset value, and the rate of change of one phase current of the other two phase currents is positive and the rate of change of the other phase current is negative, then it is determined that the Y-bridge meets the first commutation success condition.

[0160] In one embodiment, when the processor executes the computer program, it further performs the following steps: determining the commutator valves on the lower arms of the two phases other than the target phase in the Y-bridge as the first commutator valve group that has failed to commutate.

[0161] In one embodiment, when the processor executes the computer program, it also performs the following steps: if the difference between the target phase current and the line current in the D-bridge is less than a preset value, and the rate of change of one phase current of the other two phase currents is positive and the rate of change of the other phase current is negative, then the D-bridge is determined to meet the second commutation success condition.

[0162] In one embodiment, when the processor executes the computer program, it also performs the following steps: determining that the commutator valves on the lower arms of the two phases other than the target phase in the D-bridge are the second commutator valve group that has failed to commutate.

[0163] In one embodiment, when the processor executes the computer program, it further performs the following steps: acquiring the phase currents of the Y-bridge; and identifying the phase with a negative phase current and satisfying the first current judgment condition as the target phase.

[0164] In one embodiment, when the processor executes the computer program, it further implements the following steps: if the sum of the target phase current and the line current in the Y-bridge is less than a preset value, and the rate of change of one phase current of the other two phase currents is positive and the rate of change of the other phase current is negative, then it is determined that the Y-bridge meets the first commutation success condition.

[0165] In one embodiment, when the processor executes the computer program, it also performs the following steps: determining the commutator valves on the upper arms of the two phases other than the target phase in the Y-bridge as the first commutator valve group that has failed to commutate.

[0166] In one embodiment, when the processor executes the computer program, it further implements the following steps: if the sum of the target phase current and the line current in the D-bridge is less than a preset value, and the rate of change of one phase current of the other two phase currents is positive and the rate of change of the other phase current is negative, then it is determined that the D-bridge meets the second commutation success condition.

[0167] In one embodiment, when the processor executes the computer program, it also performs the following steps: determining that the commutator valves on the upper arms of the two phases other than the target phase in the D-bridge are the second commutator valve group that has failed to commutate.

[0168] In one embodiment, when the processor executes the computer program, it further performs the following steps: obtaining the commutation angle; determining, based on the commutation angle, the delay time before detecting whether the Y-bridge meets the first commutation success condition, and the delay time before detecting whether the D-bridge of the converter meets the second commutation success condition.

[0169] In one embodiment, when the processor executes the computer program, it further performs the following steps: obtaining the line current, turn-off angle, commutation line voltage on the valve side of the converter transformer connected to the converter, and commutation reactance of the converter; and calculating the commutation angle based on the line current, turn-off angle, commutation line voltage, and commutation reactance.

[0170] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, the computer program performing the following steps when executed by a processor:

[0171] The target phase in a non-commutation state is determined from each phase of the Y-bridge of the converter; it is checked whether the Y-bridge meets the first commutation success condition; if the first commutation success condition is not met, the first commutation failure valve group is determined from the commutation valves contained in each phase of the Y-bridge other than the target phase; if the first commutation success condition is met, it is checked whether the D-bridge of the converter meets the second commutation success condition, and if the second commutation success condition is not met, the second commutation failure valve group is determined from the commutation valves contained in the D-bridge.

[0172] In one embodiment, when the computer program is executed by the processor, it further performs the following steps: acquiring the phase current of each phase of the Y-bridge; and identifying the phase with positive current and satisfying the first current judgment condition as the target phase.

[0173] In one embodiment, when the computer program is executed by the processor, it further implements the following steps: if the difference between the target phase current and the line current in the Y-bridge is less than a preset value, and the rate of change of one phase current of the other two phase currents is positive and the rate of change of the other phase current is negative, then it is determined that the Y-bridge meets the first commutation success condition.

[0174] In one embodiment, when the computer program is executed by the processor, it further performs the following steps: determining the commutator valves on the lower arms of the two phases other than the target phase in the Y-bridge as the first commutator valve group that has failed to commutate.

[0175] In one embodiment, when the computer program is executed by the processor, it further implements the following steps: if the difference between the target phase current and the line current in the D-bridge is less than a preset value, and the rate of change of one phase current of the other two phase currents is positive and the rate of change of the other phase current is negative, then it is determined that the D-bridge meets the second commutation success condition.

[0176] In one embodiment, when the computer program is executed by the processor, it further performs the following steps: determining that the commutator valves on the lower arms of the two phases other than the target phase in the D-bridge are the second commutator valve group that has failed to commutate.

[0177] In one embodiment, when the computer program is executed by the processor, it further performs the following steps: acquiring the phase currents of the Y-bridge; and identifying the phase with a negative phase current and satisfying the first current judgment condition as the target phase.

[0178] In one embodiment, when the computer program is executed by the processor, it further implements the following steps: if the sum of the target phase current and the line current in the Y-bridge is less than a preset value, and the rate of change of one phase current of the other two phase currents is positive and the rate of change of the other phase current is negative, then it is determined that the Y-bridge meets the first commutation success condition.

[0179] In one embodiment, when the computer program is executed by the processor, it further performs the following steps: determining the commutator valves on the upper arms of the two phases other than the target phase in the Y-bridge as the first commutator valve group that has failed to commutate.

[0180] In one embodiment, when the computer program is executed by the processor, it further implements the following steps: if the sum of the target phase current and the line current in the D-bridge is less than a preset value, and the rate of change of one phase current of the other two phase currents is positive and the rate of change of the other phase current is negative, then it is determined that the D-bridge meets the second commutation success condition.

[0181] In one embodiment, when the computer program is executed by the processor, it further performs the following steps: determining that the commutator valves on the upper arms of the two phases other than the target phase in the D-bridge are the second commutator valve group that has failed to commutate.

[0182] In one embodiment, when the computer program is executed by the processor, it further performs the following steps: obtaining the commutation angle; determining, based on the commutation angle, the delay time before detecting whether the Y-bridge meets the first commutation success condition, and the delay time before detecting whether the D-bridge of the converter meets the second commutation success condition.

[0183] In one embodiment, when the computer program is executed by the processor, it further performs the following steps: obtaining the line current, turn-off angle, commutation line voltage on the valve side of the converter transformer connected to the converter, and commutation reactance of the converter; and calculating the commutation angle based on the line current, turn-off angle, commutation line voltage, and commutation reactance.

[0184] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, performs the following steps:

[0185] The target phase in a non-commutation state is determined from each phase of the Y-bridge of the converter; it is checked whether the Y-bridge meets the first commutation success condition; if the first commutation success condition is not met, the first commutation failure valve group is determined from the commutation valves contained in each phase of the Y-bridge other than the target phase; if the first commutation success condition is met, it is checked whether the D-bridge of the converter meets the second commutation success condition, and if the second commutation success condition is not met, the second commutation failure valve group is determined from the commutation valves contained in the D-bridge.

[0186] In one embodiment, when the computer program is executed by the processor, it further performs the following steps: acquiring the phase current of each phase of the Y-bridge; and identifying the phase with positive current and satisfying the first current judgment condition as the target phase.

[0187] In one embodiment, when the computer program is executed by the processor, it further implements the following steps: if the difference between the target phase current and the line current in the Y-bridge is less than a preset value, and the rate of change of one phase current of the other two phase currents is positive and the rate of change of the other phase current is negative, then it is determined that the Y-bridge meets the first commutation success condition.

[0188] In one embodiment, when the computer program is executed by the processor, it further performs the following steps: determining the commutator valves on the lower arms of the two phases other than the target phase in the Y-bridge as the first commutator valve group that has failed to commutate.

[0189] In one embodiment, when the computer program is executed by the processor, it further implements the following steps: if the difference between the target phase current and the line current in the D-bridge is less than a preset value, and the rate of change of one phase current of the other two phase currents is positive and the rate of change of the other phase current is negative, then it is determined that the D-bridge meets the second commutation success condition.

[0190] In one embodiment, when the computer program is executed by the processor, it further performs the following steps: determining that the commutator valves on the lower arms of the two phases other than the target phase in the D-bridge are the second commutator valve group that has failed to commutate.

[0191] In one embodiment, when the computer program is executed by the processor, it further performs the following steps: acquiring the phase currents of the Y-bridge; and identifying the phase with a negative phase current and satisfying the first current judgment condition as the target phase.

[0192] In one embodiment, when the computer program is executed by the processor, it further implements the following steps: if the sum of the target phase current and the line current in the Y-bridge is less than a preset value, and the rate of change of one phase current of the other two phase currents is positive and the rate of change of the other phase current is negative, then it is determined that the Y-bridge meets the first commutation success condition.

[0193] In one embodiment, when the computer program is executed by the processor, it further performs the following steps: determining the commutator valves on the upper arms of the two phases other than the target phase in the Y-bridge as the first commutator valve group that has failed to commutate.

[0194] In one embodiment, when the computer program is executed by the processor, it further implements the following steps: if the sum of the target phase current and the line current in the D-bridge is less than a preset value, and the rate of change of one phase current of the other two phase currents is positive and the rate of change of the other phase current is negative, then it is determined that the D-bridge meets the second commutation success condition.

[0195] In one embodiment, when the computer program is executed by the processor, it further performs the following steps: determining that the commutator valves on the upper arms of the two phases other than the target phase in the D-bridge are the second commutator valve group that has failed to commutate.

[0196] In one embodiment, when the computer program is executed by the processor, it further performs the following steps: obtaining the commutation angle; determining, based on the commutation angle, the delay time before detecting whether the Y-bridge meets the first commutation success condition, and the delay time before detecting whether the D-bridge of the converter meets the second commutation success condition.

[0197] In one embodiment, when the computer program is executed by the processor, it further performs the following steps: obtaining the line current, turn-off angle, commutation line voltage on the valve side of the converter transformer connected to the converter, and commutation reactance of the converter; and calculating the commutation angle based on the line current, turn-off angle, commutation line voltage, and commutation reactance.

[0198] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0199] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0200] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0201] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for detecting commutation failure, characterized in that, The method includes: Identify the target phase that is in a non-commutation state from each phase of the Y-bridge of the converter; Detect whether the Y-bridge meets the first commutation success condition; If the first commutation success condition is not met, then the first commutation failure group is determined from the commutation valves contained in each phase of the Y-bridge other than the target phase. If the first commutation success condition is met, then it is detected whether the D-bridge of the converter meets the second commutation success condition. If the second commutation success condition is not met, then the second commutation failure valve group is determined from the commutation valves included in the D-bridge. Determining the target phase in a non-commutation state from each phase of the Y-bridge of the converter includes: Obtain the phase current of the Y-bridge; The phase in each phase current that is positive and satisfies the first current judgment condition is determined as the target phase; The detection of whether the Y-bridge meets the first commutation success condition includes: If the difference between the target phase current and the line current in the Y-bridge is less than a preset value, and the change rate of one phase current of the other two phase currents is positive and the change rate of the other phase current is negative, then the Y-bridge is determined to meet the first commutation success condition. The determination of the first commutation valve group that has failed from the commutation valves included in each phase of the Y-bridge other than the target phase includes: The commutator valves on the lower arms of the two phases other than the target phase in the Y-bridge are identified as the first commutator valve group that failed to commutate. The detection of whether the D-bridge of the converter meets the second commutation success condition includes: If the difference between the target phase current and the line current in the D-bridge is less than the preset value, and the change rate of one phase current of the other two phase currents is positive and the change rate of the other phase current is negative, then the D-bridge is determined to meet the second commutation success condition. The second commutator group for determining commutation failure from the commutator valves included in the D-bridge includes: The commutator valves on the lower arms of the two phases other than the target phase in the D bridge are identified as the second commutator valve group that failed to commutate.

2. The method according to claim 1, characterized in that, Determining the target phase in a non-commutation state from each phase of the Y-bridge of the converter includes: Obtain the phase current of the Y-bridge; The phase with a negative phase current and that satisfies the first current judgment condition is identified as the target phase. The detection of whether the Y-bridge meets the first commutation success condition includes: If the sum of the target phase current and the line current in the Y-bridge is less than a preset value, and the change rate of one phase current of the other two phase currents is positive and the change rate of the other phase current is negative, then the Y-bridge is determined to meet the first commutation success condition. The determination of the first commutation valve group that has failed from the commutation valves included in each phase of the Y-bridge other than the target phase includes: The commutator valves on the upper arms of the two phases other than the target phase in the Y-bridge are identified as the first commutator valve group that failed to commutate. The detection of whether the D-bridge of the converter meets the second commutation success condition includes: If the sum of the target phase current and the line current in the D-bridge is less than the preset value, and the change rate of one phase current of the other two phase currents is positive and the change rate of the other phase current is negative, then the D-bridge is determined to meet the second commutation success condition. The second commutator group for determining commutation failure from the commutator valves included in the D-bridge includes: The commutator valves on the upper arms of the two phases other than the target phase in the D bridge are identified as the second commutator valve group that failed to commutate.

3. The method according to claim 1, characterized in that, The method further includes: Obtain the phase angle; Based on the commutation angle, determine the delay time before detecting whether the Y-bridge meets the first commutation success condition, and determine the delay time before detecting whether the D-bridge of the converter meets the second commutation success condition.

4. The method according to claim 3, characterized in that, The acquisition of the commutation angle includes: The line current, turn-off angle, valve-side commutation line voltage of the converter transformer connected to the converter, and commutation reactance of the converter are obtained. The commutation angle is calculated based on the line current, the turn-off angle, the commutation line voltage, and the commutation reactance.

5. The method according to claim 1 or 2, characterized in that, The first current determination condition is that, among the phase currents, the difference between one phase current and the line current is less than a preset value, and the sum of one phase current and the line current of the other two phase currents is less than the preset value, and the other phase current is less than the preset value.

6. A commutation failure detection device, characterized in that, The device includes: The first determining module is used to determine the target phase that is in a non-commutation state from each phase of the Y-bridge of the converter; The detection module is used to detect whether the Y-bridge meets the first commutation success condition; The second determining module is used to determine the first commutation failure group from the commutation valves contained in each phase of the Y-bridge other than the target phase if the first commutation success condition is not met. The third determining module is used to detect whether the D-bridge of the converter meets the second commutation success condition if the first commutation success condition is met, and to determine the second commutation failure group from the commutation valves included in the D-bridge if the second commutation success condition is not met. The first determining module is specifically used for: acquiring the phase current of the Y-bridge; and determining the phase with positive current and satisfying the first current judgment condition as the target phase. The detection module is specifically used to: if the difference between the target phase current and the line current in the Y-bridge is less than a preset value, and the change rate of one phase current of the other two phase currents is positive and the change rate of the other phase current is negative, then determine that the Y-bridge meets the first commutation success condition. The second determining module is specifically used to: determine that the commutator valves on the lower arms of the two phases other than the target phase in the Y-bridge are the first commutator valve group that has failed to commutate; The third determining module is specifically used to: if the difference between the target phase current and the line current in the D-bridge is less than the preset value, and the change rate of one phase current of the other two phase currents is positive and the change rate of the other phase current is negative, then determine that the D-bridge meets the second commutation success condition; determine that the commutator valves on the lower bridge arms of the two phases other than the target phase in the D-bridge are the second commutator valve group that failed to commutate.

7. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

9. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

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