Loss balancing control method and system for NPC circuit under single switch failure

Abstract

The application discloses a loss balancing control method and system of NPC circuit under single switch tube fault, relates to the technical field of data analysis, and realizes the self-control of circuit loss balancing while guaranteeing the output performance of the NPC circuit under single switch tube fault through the following steps: building a synchronous detection platform to collect real-time operation data of switch tube units and circuit paths in the NPC circuit and performing periodical log storage; positioning each switch tube unit in the NPC circuit and performing fault analysis; positioning the circuit path where the faulty switch tube is located based on the switch tube fault analysis data, and performing loss redistribution analysis on each circuit path by analyzing the loss data of the NPC circuit; performing loss dynamic balancing optimization analysis on each circuit path according to the loss redistribution data on each circuit path in the NPC circuit and in combination with the operating switch state of the corresponding circuit path, and outputting a control scheme of the switch tube of the corresponding circuit path according to the analysis result.

Description

Technical Field

[0001] This invention relates to the field of data analysis, specifically to a loss balancing control method and system for NPC circuits under single-switch fault conditions. Background Technology

[0002] The NPC circuit is a neutral-point clamped three-level circuit, a typical multi-level power electronic topology, which is widely used in new energy power generation, motor drive and other fields.

[0003] In current applications of NPC circuits, a common problem is that when a single switch fails, the associated circuits also fail. In this situation, the remaining components must bear additional power consumption to keep the circuit running, which can easily lead to localized overheating or secondary failures. Traditional fault control methods focus on monitoring the circuit during normal operation, making it difficult to balance circuit output performance and loss balance control when a switch failure occurs. Existing fault control methods often sacrifice efficiency for stability and lack dynamic adjustment capabilities. Summary of the Invention

[0004] The purpose of this invention is to provide a loss balancing control method and system for NPC circuits under single-switch failure, so as to solve the problems raised in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A loss balancing control method for an NPC circuit under single-switch failure, comprising the following steps:

[0007] A synchronous detection platform is built to collect real-time operating data of the switching transistor units and circuit paths in the NPC circuit, and the collected data is periodically logged.

[0008] By locating each switching transistor unit in the NPC circuit and retrieving the periodic operation data of the corresponding switching transistor unit for fault analysis; based on the switching transistor fault analysis data, the circuit path where the faulty switching transistor is located is located, and by analyzing the loss data of the NPC circuit, loss redistribution analysis is performed on each circuit path.

[0009] Based on the loss redistribution data of each circuit path in the NPC circuit, and combined with the working switch status of the corresponding circuit path, a dynamic loss balance optimization analysis is performed, and a control scheme for the corresponding circuit path switch is output based on the analysis results.

[0010] Furthermore, the synchronous detection platform is an interactive visual management platform, which uses several sensor devices to collect operating data of the switching transistor units and circuit paths in the NPC path, and transmits the data to the visual interface for output via a signal network. The operating data of the switching transistor units includes on-state voltage data, collector current data, and switching frequency; the operating data of the circuit paths includes output current data and output voltage data of the corresponding circuit paths. The sensor devices include current sensors and voltage sensors, used to collect the current and voltage data of the switching transistor units and circuit paths, respectively; and a counter device is used to record the switching frequency data of the switching transistors.

[0011] The real-time operating data of the switching transistors and the operating data of the circuit path collected in the NPC circuit are marked with the collection timestamp, and corresponding sets of periodic operating data of the switching transistor unit and the circuit path are constructed respectively. Log storage is performed by setting an update period. Specifically, the update period length is manually set. When the collection period length meets the update period length, the operating data of the switching transistors and the operating data of the circuit path collected in the current collection period are logged and stored in the database as historical data, and the data collection for the new period is started.

[0012] Furthermore, in the NPC circuit, the circuit paths are labeled and located, and the switching transistor units on each circuit path are also labeled and located. Labeling and location refers to assigning labels to the bridge arms and corresponding switching transistor units in the NPC circuit, and locating the circuit paths based on the labels. The periodic operating data sets of the corresponding switching transistor units are retrieved, and the safety status and transient status of the corresponding switching transistor unit operating data are analyzed in real time. Based on the analysis results, faulty switching transistor units are marked as abnormal. The safety status analysis of the switching transistor unit operating data involves comparing the operating data at each time point in the periodic operating data set with the corresponding safety range. If it is within the safety range, the operating data at the corresponding time point is considered normal; otherwise, it is considered abnormal. The transient status analysis of the switching transistor unit operating data involves comparing the absolute value of the difference between the operating data at adjacent time points in the periodic operating data set with the corresponding safety threshold. If it is less than or equal to the safety threshold, the operating data at the adjacent time point is considered normal; otherwise, it is considered abnormal. The safety range and safety threshold are manually set. Switching transistor unit faults include open circuits and short circuits.

[0013] Based on the analysis data of the faulty switching transistor unit, the location tag of the faulty switching transistor unit is determined. Then, based on the periodic operation data set of the switching transistor unit, the periodic operation data sets of the normal switching transistor unit and the periodic operation data set of the faulty switching transistor unit in normal state are retrieved respectively. The loss data of the switching transistor unit during normal operation is analyzed. The loss data of the switching transistor unit during normal operation includes the switching transistor unit's conduction loss and switching loss; its calculation formula is as follows:

[0014] ;

[0015] Among them, P con,k V represents the conduction loss of the switching transistor unit corresponding to label k; k I is the on-state voltage of the switching transistor unit corresponding to label k; k D represents the collector current of the switching transistor unit corresponding to label k. k The duty cycle of the switching transistor unit corresponding to label k;

[0016] ;

[0017] Among them, P sw,k f represents the switching loss of the switching transistor unit corresponding to label k; k E represents the periodic switching frequency of the switching transistor unit corresponding to label k. on E represents the turn-on energy of the switching transistor unit corresponding to label k. off This represents the turn-off energy of the switching transistor unit corresponding to label k; the on-duty cycle, turn-on energy, and turn-off energy of the switching transistor unit can be obtained from the device data stored in the database.

[0018] Based on the analysis results of the loss data during normal operation of each switching transistor unit, the loss data of the circuit path corresponding to each switching transistor is analyzed separately; the calculation formula is as follows:

[0019] ;

[0020] Among them, P sy,G P represents the total loss of the circuit path corresponding to label G; con,G P represents the conduction loss of the circuit path corresponding to label G; sw,G Let G be the switching loss of the circuit path corresponding to label G; where the conduction loss of the corresponding circuit path is the sum of the conduction losses of each switching transistor unit on the circuit path; and the switching loss of the corresponding circuit path is the sum of the switching losses of each switching transistor unit on the circuit path.

[0021] Furthermore, based on the loss analysis data of the switching transistors under normal operation on each circuit path, the faulty switching transistor is located, and the circuit path containing the faulty switching transistor is determined and marked. Combining the loss data of the faulty circuit path with the loss data of the normal circuit path, a loss redistribution analysis of the remaining normal circuit path is performed on the NPC circuit. The specific analysis and calculation are as follows:

[0022] ;

[0023] in, The total loss after redistribution of the circuit path labeled G in the set of normal circuit paths; The total loss before redistribution of the circuit path labeled G in the set of normal circuit paths; f is the switching frequency of the switching transistor unit labeled k on the circuit path labeled G in the set of normal circuit paths; all This is the sum of the switching frequencies of the switching transistor units on each circuit path in the set of normal circuit paths; The total loss before redistribution of the circuit path labeled G in the faulty circuit path set; where HG is the normal circuit path set, and YG is the faulty circuit path set; the normal circuit path set contains the labels of the remaining normal circuit paths excluding the faulty circuit paths; the faulty circuit path set contains the labels of the faulty circuit paths.

[0024] Based on the loss redistribution analysis data of normal circuit paths, this paper constructs a set of corresponding operating switch states by counting the number of operating switch states on each normal circuit path. It then determines the conduction state combination of each switching transistor unit on the normal circuit path corresponding to each operating switch state. The paper analyzes the dynamic balance optimization of circuit path losses under each operating switch state set within the set of operating switch states for each normal circuit path. Based on the analysis results, it outputs the optimal combination of switching transistor unit conduction states corresponding to the operating switch states, which serves as the optimal control scheme for the switching transistor units on each normal circuit path. The specific analysis of the dynamic balance optimization of circuit path losses under the operating switch states for each normal circuit path is as follows:

[0025] ;

[0026] in, The loss dynamic balance optimization analysis index is the working state labeled Y in the working switch state set corresponding to the circuit path labeled G in the normal circuit path set. The output current of the circuit path labeled G in the set of normal circuit paths; The output voltage of the circuit path labeled G in the set of normal circuit paths; I c and Vc These correspond to the reference current and reference voltage of the circuit path labeled G in the set of normal circuit paths, respectively; P HG α1, α2, and α3 are the sum of the total losses after the redistribution of each circuit path in the normal circuit path set; α1, α2, and α3 are artificially preset weighting coefficients; based on the dynamic balance optimization analysis index analysis results of the circuit path loss in each working state in the working switch state set corresponding to each circuit path in the normal circuit path set, the working state corresponding to the minimum value is the optimal working state of dynamic balance loss of the corresponding circuit path, and then the combination of the conduction states of each switching unit on the corresponding circuit path is the optimal control scheme of the switching unit.

[0027] Furthermore, the fault status of the switching transistor units on each circuit path in the NPC circuit is fed back and prompted through the visual interface of the synchronous detection platform.

[0028] When a faulty switching transistor unit exists, the optimal control scheme for the switching transistor unit is obtained from the dynamic balance optimization analysis of the losses of each normal circuit path.

[0029] A loss equalization control system for an NPC circuit under single switch failure, the system comprising a circuit monitoring module, a switch failure analysis module, an equalization control analysis module, and a feedback control module;

[0030] The circuit monitoring module collects real-time operational data of the switching transistor units and circuit paths in the NPC circuit by building a synchronous detection platform, and stores the collected data in periodic logs. The switching transistor fault analysis module locates each switching transistor unit in the NPC circuit and retrieves the periodic operational data of the corresponding switching transistor unit for fault analysis. The equalization control analysis module locates the circuit path where the faulty switching transistor is located based on the switching transistor fault analysis data, and performs loss redistribution analysis on each circuit path by analyzing the loss data of the NPC circuit. Based on the analysis data and the operating switch status of the corresponding circuit path, it performs dynamic loss equalization optimization analysis to determine the control scheme of the switching transistors of the corresponding circuit path. The feedback control module provides feedback to the faulty switching transistors on each circuit path and outputs the control scheme of the corresponding circuit path switching transistors.

[0031] Furthermore, the circuit monitoring module includes a synchronization data detection unit and a log update storage unit;

[0032] The synchronization data detection unit includes a synchronization detection platform, which is an interactive visual management platform. The synchronization detection platform is associated with several sensor devices to collect the operating data of the switching transistor unit and the circuit path in the NPC path, and transmits the data to the visual interface for output through a signal network. The operating data of the switching transistor unit includes conduction voltage data, collector current data, and switching frequency. The operating data of the circuit path includes the output current data and output voltage data of the corresponding circuit path.

[0033] The log update storage unit marks the real-time switching transistor operation data and circuit path operation data collected in the NPC circuit with the collection timestamp, respectively constructs the corresponding switching transistor unit periodic operation data set and circuit path periodic operation data set, and stores the log by setting the update period.

[0034] Furthermore, the switching transistor fault analysis module includes a switching transistor fault location unit and a switching transistor loss analysis unit;

[0035] The switching transistor fault location unit labels and locates the circuit path in the NPC circuit, and labels and locates the switching transistor unit on each circuit path; it retrieves the periodic operation data set of the corresponding switching transistor unit, analyzes the safety status and transition status of the corresponding switching transistor unit operation data in real time, and marks the faulty switching transistor unit with anomaly location based on the analysis results.

[0036] The switching transistor loss analysis unit determines the location tag of the faulty switching transistor unit based on the analysis data of the faulty switching transistor unit, and retrieves the periodic operation data sets of normal switching transistor units and the periodic operation data sets of the faulty switching transistor unit in normal state, respectively, to analyze the loss data of the switching transistor unit during normal operation. The loss data of the switching transistor unit during normal operation includes the switching transistor unit's conduction loss and switching loss. Based on the analysis results of the loss data of each switching transistor unit during normal operation, the loss data of the circuit path corresponding to each switching transistor is analyzed.

[0037] Furthermore, the equilibrium control analysis module includes a path loss redistribution unit and a loss equilibrium optimal analysis unit.

[0038] The path loss redistribution unit, based on the loss analysis data of the switching transistor units under normal operation on each circuit path, locates the currently faulty switching transistor unit, determines the circuit path where the faulty switching transistor unit is located, and marks the faulty circuit path; combining the loss data of the faulty circuit path with the loss data of the normal circuit path, it performs loss redistribution analysis of the remaining normal circuit path of the NPC circuit.

[0039] The loss balancing optimal analysis unit, based on the loss redistribution analysis data of normal circuit paths, constructs a corresponding set of operating switch states by corresponding to the number of operating switch states on each normal circuit path, determines the combination of conduction states of each switching transistor unit on the normal circuit path corresponding to each operating switch state; analyzes the loss dynamic balancing optimal analysis of the circuit path under each operating switch state in the set of operating switch states of each normal circuit path, and outputs the combination of conduction states of the switching transistor units corresponding to the operating switch states with optimized loss dynamic balancing based on the analysis results, as the optimal control scheme for the switching transistor units on each normal circuit path.

[0040] Furthermore, the feedback control module includes a fault feedback unit and a control scheme output unit;

[0041] The fault feedback unit provides feedback on the fault status of the switching transistor units on each circuit path in the NPC circuit through the visual interface of the synchronous detection platform.

[0042] When a faulty switching transistor unit exists, the output unit of the control scheme outputs the optimal control scheme for the switching transistor unit based on the dynamic balance optimization analysis of the loss of each normal circuit path.

[0043] Compared with the prior art, the beneficial effects of the present invention are:

[0044] This invention combines sensor devices to construct a monitoring platform to achieve circuit data acquisition, fault location analysis, loss balance control analysis, and scheme output in the case of a single-switch failure in an NPC circuit. It realizes dynamic control of circuit loss in the case of a single-switch failure in an NPC circuit. By redistributing the loss of the normal circuit when a fault occurs, and performing loss balance optimization analysis on the operating states of each circuit based on this, it outputs the optimal switching control combination based on the optimization analysis, thereby achieving autonomous control of circuit loss balance while ensuring the output performance of the NPC circuit with a single-switch failure. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the loss equalization control system of the NPC circuit under single-switch failure according to the present invention.

[0046] Figure 2 This is a flowchart illustrating the loss balancing control method for an NPC circuit under single-switch fault according to the present invention. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] Example: Figure 1 As shown, the present invention provides a technical solution:

[0049] A loss equalization control system for an NPC circuit under single switch failure, wherein the system includes a circuit monitoring module, a switch failure analysis module, an equalization control analysis module, and a feedback control module;

[0050] The circuit monitoring module collects real-time operational data of the switching transistor units and circuit paths in the NPC circuit by building a synchronous detection platform, and stores the collected data in periodic logs. The switching transistor fault analysis module locates each switching transistor unit in the NPC circuit and retrieves the periodic operational data of the corresponding switching transistor unit for fault analysis. The equalization control analysis module locates the circuit path where the faulty switching transistor is located based on the switching transistor fault analysis data, and performs loss redistribution analysis on each circuit path by analyzing the loss data of the NPC circuit. Based on the analysis data and the operating switch status of the corresponding circuit path, the module performs dynamic loss equalization optimization analysis to determine the control scheme of the switching transistors of the corresponding circuit path. The feedback control module provides feedback on the faulty switching transistors on each circuit path and outputs the control scheme of the corresponding circuit path switching transistors.

[0051] Furthermore, the circuit monitoring module includes a synchronization data detection unit and a log update storage unit;

[0052] The synchronous data detection unit includes a synchronous detection platform, which is an interactive visual management platform. The synchronous detection platform is connected to several sensor devices to collect the operating data of the switching transistor units and the circuit path in the NPC path, and transmits the data to the visual interface for output through a signal network. The operating data of the switching transistor units includes conduction voltage data, collector current data, and switching frequency; the operating data of the circuit path includes the output current data and output voltage data of the corresponding circuit path.

[0053] The log update storage unit marks the real-time switching transistor operation data and circuit path operation data collected in the NPC circuit with the collection timestamp, and constructs corresponding periodic operation data sets for the switching transistor unit and the circuit path respectively, and stores the logs by setting the update period.

[0054] Furthermore, the switching transistor fault analysis module includes a switching transistor fault location unit and a switching transistor loss analysis unit;

[0055] The switching transistor fault location unit labels and locates the circuit path in the NPC circuit, and labels and locates the switching transistor unit on each circuit path; it retrieves the periodic operation data set of the corresponding switching transistor unit, analyzes the safety status and transition status of the corresponding switching transistor unit operation data in real time, and marks the faulty switching transistor unit with anomaly location based on the analysis results.

[0056] The switching transistor loss analysis unit determines the location tag of the faulty switching transistor unit based on the analysis data of the faulty switching transistor unit, and retrieves the periodic operation data sets of normal switching transistor units and the periodic operation data sets of the faulty switching transistor unit in normal state, respectively, to analyze the loss data of the switching transistor unit during normal operation. The loss data of the switching transistor unit during normal operation includes the switching transistor unit's conduction loss and switching loss. Based on the analysis results of the loss data of each switching transistor unit during normal operation, the loss data of the circuit path corresponding to each switching transistor is analyzed.

[0057] Furthermore, the equilibrium control analysis module includes a path loss redistribution unit and a loss equilibrium optimal analysis unit.

[0058] The path loss redistribution unit, based on the loss analysis data of the switching transistors under normal operation on each circuit path, locates the currently faulty switching transistor, determines the circuit path where the faulty switching transistor is located, and marks the faulty circuit path; combining the loss data of the faulty circuit path with the loss data of the normal circuit path, it performs loss redistribution analysis of the remaining normal circuit path of the NPC circuit.

[0059] The loss balancing optimal analysis unit, based on the loss redistribution analysis data of normal circuit paths, constructs a corresponding set of operating switch states by corresponding to the number of operating switch states on each normal circuit path, and determines the combination of conduction states of each switching transistor unit on the normal circuit path corresponding to each operating switch state. It analyzes the loss dynamic balancing optimization of the circuit path under each operating switch state in the set of operating switch states of each normal circuit path, and outputs the combination of conduction states of the switching transistor units corresponding to the operating switch states with optimized loss dynamic balancing based on the analysis results, which serves as the optimal control scheme for the switching transistor units on each normal circuit path.

[0060] Furthermore, the feedback control module includes a fault feedback unit and a control scheme output unit;

[0061] The fault feedback unit provides feedback on the fault status of the switching transistor units in each circuit path of the NPC circuit through the visual interface of the synchronous detection platform.

[0062] When a faulty switching transistor unit exists, the output unit of the control scheme outputs the optimal control scheme of the switching transistor unit based on the dynamic balance optimization analysis of the loss of each normal circuit path.

[0063] like Figure 2 As shown, the present invention provides another technical solution:

[0064] A loss balancing control method for an NPC circuit under single-switch failure, comprising the following steps:

[0065] A synchronous detection platform is built to collect real-time operating data of the switching transistor units and circuit paths in the NPC circuit, and the collected data is periodically logged.

[0066] By locating each switching transistor unit in the NPC circuit and retrieving the periodic operation data of the corresponding switching transistor unit for fault analysis; based on the switching transistor fault analysis data, the circuit path where the faulty switching transistor is located is located, and by analyzing the loss data of the NPC circuit, loss redistribution analysis is performed on each circuit path.

[0067] Based on the loss redistribution data of each circuit path in the NPC circuit, and combined with the working switch status of the corresponding circuit path, a dynamic loss balance optimization analysis is performed, and a control scheme for the corresponding circuit path switch is output based on the analysis results.

[0068] Furthermore, the synchronous detection platform is an interactive, visual management platform. It consists of several interconnected sensor devices that collect operating data from the switching transistor units and circuit paths within the NPC path, and transmit this data to a visual interface via a signal network for output. The switching transistor unit operating data includes on-state voltage data, collector current data, and switching frequency; the circuit path operating data includes the output current data and output voltage data for the corresponding circuit path. The sensor devices include current sensors and voltage sensors, used to collect the current and voltage data of the switching transistor units and circuit paths, respectively. A counter device is used to record the switching frequency data of the switching transistors.

[0069] The real-time operating data of the switching transistors and the operating data of the circuit path collected in the NPC circuit are marked with the collection timestamp, and corresponding sets of periodic operating data of the switching transistor unit and the circuit path are constructed respectively. Log storage is performed by setting an update period. Specifically, the update period length is manually set. When the collection period length meets the update period length, the operating data of the switching transistors and the operating data of the circuit path collected in the current collection period are logged and stored in the database as historical data, and the data collection for the new period is started.

[0070] Furthermore, in the NPC circuit, the circuit paths are labeled and located, and the switching transistor units on each circuit path are also labeled and located. Label location refers to assigning labels to the bridge arms and corresponding switching transistor units in the NPC circuit, and locating the circuit paths based on the labels. The periodic operation data sets of the corresponding switching transistor units are retrieved, and the safety status and transition status of the corresponding switching transistor unit operation data are analyzed in real time. Based on the analysis results, faulty switching transistor units are marked as abnormal. The safety status analysis of the switching transistor unit operation data is achieved by comparing the operation data at each time point in the periodic operation data set with the corresponding safety range. If it is within the safety range, the operation data at the corresponding time point is considered normal; otherwise, it is considered abnormal. The transition status analysis of the switching transistor unit operation data is achieved by comparing the absolute value of the difference between the operation data at adjacent time points in the periodic operation data set with the corresponding safety threshold. If it is less than or equal to the safety threshold, the operation data at the adjacent time points is considered normal; otherwise, it is considered abnormal. The safety range and safety threshold are manually set. Switching transistor unit faults include open circuits and short circuits.

[0071] Based on the analysis data of the faulty switching transistor unit, the location tag of the faulty switching transistor unit is determined. Then, based on the periodic operation data set of the switching transistor unit, the periodic operation data sets of the normal switching transistor unit and the periodic operation data set of the faulty switching transistor unit in normal state are retrieved separately to analyze the loss data of the switching transistor unit during normal operation. The loss data of the switching transistor unit during normal operation includes the conduction loss and the switching loss of the switching transistor; the calculation formula is as follows:

[0072] ;

[0073] Among them, P con,k V represents the conduction loss of the switching transistor unit corresponding to label k; k I is the on-state voltage of the switching transistor unit corresponding to label k; k D represents the collector current of the switching transistor unit corresponding to label k. k The duty cycle of the switching transistor unit corresponding to label k;

[0074] ;

[0075] Among them, P sw,k f represents the switching loss of the switching transistor unit corresponding to label k; k E represents the periodic switching frequency of the switching transistor unit corresponding to label k. on E represents the turn-on energy of the switching transistor unit corresponding to label k. offThis represents the turn-off energy of the switching transistor unit corresponding to label k; the on-duty cycle, turn-on energy, and turn-off energy of the switching transistor unit can be obtained from the device data stored in the database.

[0076] Based on the analysis results of the loss data during normal operation of each switching transistor unit, the loss data of the circuit path corresponding to each switching transistor is analyzed separately; the calculation formula is as follows:

[0077] ;

[0078] Among them, P sy,G P represents the total loss of the circuit path corresponding to label G; con,G P represents the conduction loss of the circuit path corresponding to label G; sw,G Let G be the switching loss of the circuit path corresponding to label G; where the conduction loss of the corresponding circuit path is the sum of the conduction losses of each switching transistor unit on the circuit path; and the switching loss of the corresponding circuit path is the sum of the switching losses of each switching transistor unit on the circuit path.

[0079] Furthermore, based on the loss analysis data of the switching transistors under normal operation on each circuit path, the faulty switching transistor is located, and the circuit path containing the faulty switching transistor is determined and marked. Combining the loss data of the faulty circuit path with the loss data of the normal circuit path, a loss redistribution analysis of the remaining normal circuit path is performed on the NPC circuit. The specific analysis and calculation are as follows:

[0080] ;

[0081] in, The total loss after redistribution of the circuit path labeled G in the set of normal circuit paths; The total loss before redistribution of the circuit path labeled G in the set of normal circuit paths; f is the switching frequency of the switching transistor unit labeled k on the circuit path labeled G in the set of normal circuit paths; all This is the sum of the switching frequencies of the switching transistor units on each circuit path in the set of normal circuit paths; The total loss before redistribution of the circuit path labeled G in the faulty circuit path set; where HG is the normal circuit path set, and YG is the faulty circuit path set; the normal circuit path set contains the labels of the remaining normal circuit paths excluding the faulty circuit paths; the faulty circuit path set contains the labels of the faulty circuit paths.

[0082] Based on the loss redistribution analysis data of normal circuit paths, this paper constructs a set of corresponding operating switch states by counting the number of operating switch states on each normal circuit path. It then determines the conduction state combination of each switching transistor unit on the normal circuit path corresponding to each operating switch state. The paper analyzes the dynamic balance optimization of circuit path losses under each operating switch state set within the set of operating switch states for each normal circuit path. Based on the analysis results, it outputs the optimal combination of switching transistor unit conduction states corresponding to the operating switch states, which serves as the optimal control scheme for the switching transistor units on each normal circuit path. The specific analysis of the dynamic balance optimization of circuit path losses under the operating switch states for each normal circuit path is as follows:

[0083] ;

[0084] in, The loss dynamic balance optimization analysis index is the working state labeled Y in the working switch state set corresponding to the circuit path labeled G in the normal circuit path set. The output current of the circuit path labeled G in the set of normal circuit paths; The output voltage of the circuit path labeled G in the set of normal circuit paths; I c and V c These correspond to the reference current and reference voltage of the circuit path labeled G in the set of normal circuit paths, respectively; P HG α1, α2, and α3 are the sum of the total losses after the redistribution of each circuit path in the normal circuit path set; α1, α2, and α3 are artificially preset weighting coefficients; based on the analysis results of the dynamic balance optimization analysis index of circuit path loss in each working state in the working switch state set corresponding to each circuit path in the normal circuit path set, the working state corresponding to the minimum value is the optimal working state of dynamic balance of loss for the corresponding circuit path, and the combination of the conduction states of each switching unit on the corresponding circuit path is the optimal control scheme of the switching unit.

[0085] In this embodiment, the operation switch state of the NPC circuit is determined by the combination of the on and off states of the switching transistors on each circuit path, and each operation switch state corresponds to the operation logic of a specific switching transistor.

[0086] Furthermore, the fault status of the switching transistor units on each circuit path in the NPC circuit is fed back and prompted through the visual interface of the synchronous detection platform.

[0087] When a faulty switching transistor unit exists, the optimal control scheme for the switching transistor unit is obtained from the dynamic balance optimization analysis of the losses of each normal circuit path.

[0088] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A loss balancing control method for an NPC circuit under single-switch failure, characterized in that: The method includes the following steps: A synchronous detection platform is built to collect real-time operating data of the switching transistor units and circuit paths in the NPC circuit, and the collected data is periodically logged. By locating each switching transistor unit in the NPC circuit and retrieving the periodic operation data of the corresponding switching transistor unit for fault analysis; based on the switching transistor fault analysis data, the circuit path where the faulty switching transistor is located is located, and by analyzing the loss data of the NPC circuit, loss redistribution analysis is performed on each circuit path. Based on the loss redistribution data of each circuit path in the NPC circuit, and combined with the working switch status of the corresponding circuit path, a dynamic loss balance optimization analysis is performed, and a control scheme for the corresponding circuit path switch is output based on the analysis results. Based on the loss analysis data of the switching transistor units under normal operation on each circuit path, the faulty switching transistor unit is located, the circuit path where the faulty switching transistor unit is located is determined, and the faulty circuit path is marked; combined with the loss data of the faulty circuit path and the loss data of the normal circuit path, the loss redistribution analysis of the remaining normal circuit path of the NPC circuit is performed. Based on the loss redistribution analysis data of normal circuit paths, by corresponding to the number of operating switch states on each normal circuit path and constructing a corresponding set of operating switch states, the conduction state combination of each switching transistor unit on the normal circuit path corresponding to each operating switch state is determined; the loss dynamic balance optimization analysis of the circuit path under each operating switch state in the set of operating switch states of each normal circuit path is analyzed, and the conduction state combination of the switching transistor unit corresponding to the operating switch state with the optimal loss dynamic balance is output according to the analysis results, which serves as the optimal control scheme for the switching transistor unit on each normal circuit path.

2. The loss balancing control method for an NPC circuit under single-switch fault according to claim 1, characterized in that: The synchronous detection platform is an interactive visual management platform. It consists of several sensor devices that are associated to collect the operating data of the switching transistor units and the circuit path in the NPC path, and transmit the data to the visual interface for output through a signal network. The operating data of the switching transistor units includes on-state voltage data, collector current data, and switching frequency. The operating data of the circuit path includes the output current data and output voltage data of the corresponding circuit path. The real-time operating data of the switching transistors and the operating data of the circuit path collected in the NPC circuit are marked with the collection timestamp, and corresponding periodic operating data sets of the switching transistor units and the circuit path are constructed respectively. The log is stored by setting the update period.

3. The loss balancing control method for NPC circuits under single-switch faults according to claim 2, characterized in that: In the NPC circuit, the circuit paths are labeled and located, and the switching transistor units on each circuit path are labeled and located. The periodic operation data sets of the corresponding switching transistor units are retrieved, and the safety status and transition status of the corresponding switching transistor unit operation data are analyzed in real time. Based on the analysis results, the faulty switching transistor units are marked with abnormal location. Based on the analysis data of the faulty switching transistor unit, the location tag of the faulty switching transistor unit is determined. Then, based on the periodic operation data set of the switching transistor unit, the periodic operation data set of the normal switching transistor unit and the periodic operation data set of the faulty switching transistor unit in normal state are retrieved respectively to analyze the loss data of the switching transistor unit during normal operation. The loss data of the switching transistor unit during normal operation includes the switching transistor unit conduction loss and the switching loss of the switching transistor. Based on the analysis results of the loss data of each switching transistor unit during normal operation, the loss data of the circuit path corresponding to each switching transistor is analyzed separately.

4. The loss balancing control method for NPC circuits under single-switch faults according to claim 3, characterized in that: The synchronous detection platform uses a visual interface to provide feedback on the fault status of the switching transistor units in each circuit path of the NPC circuit. When a faulty switching transistor unit exists, the optimal control scheme for the switching transistor unit is obtained from the dynamic balance optimization analysis of the losses of each normal circuit path.

5. A loss balancing control system for an NPC circuit under single-switch failure, characterized in that: The system includes a circuit monitoring module, a switching transistor fault analysis module, a balance control analysis module, and a feedback control module. The circuit monitoring module collects real-time operational data of the switching transistor units and circuit paths in the NPC circuit by building a synchronous detection platform, and stores the collected data in periodic logs. The switching transistor fault analysis module locates each switching transistor unit in the NPC circuit and retrieves the periodic operational data of the corresponding switching transistor unit for fault analysis. The equalization control analysis module locates the circuit path where the faulty switching transistor is located based on the switching transistor fault analysis data, and performs loss redistribution analysis on each circuit path by analyzing the loss data of the NPC circuit. Based on the analysis data and the operating switch status of the corresponding circuit path, it performs dynamic loss equalization optimization analysis to determine the control scheme of the switching transistors of the corresponding circuit path. The feedback control module provides feedback to the faulty switching transistors on each circuit path and outputs the control scheme of the corresponding circuit path switching transistors. The equilibrium control analysis module includes a path loss redistribution unit and a loss equilibrium optimal analysis unit. The path loss redistribution unit, based on the loss analysis data of the switching transistor units under normal operation on each circuit path, locates the currently faulty switching transistor unit, determines the circuit path where the faulty switching transistor unit is located, and marks the faulty circuit path. By combining the loss data of the faulty circuit path with the loss data of the normal circuit path, a loss redistribution analysis of the remaining normal circuit path is performed on the NPC circuit. The loss balancing optimal analysis unit, based on the loss redistribution analysis data of normal circuit paths, constructs a corresponding set of operating switch states by corresponding to the number of operating switch states on each normal circuit path, determines the combination of conduction states of each switching transistor unit on the normal circuit path corresponding to each operating switch state; analyzes the loss dynamic balancing optimal analysis of the circuit path under each operating switch state in the set of operating switch states of each normal circuit path, and outputs the combination of conduction states of the switching transistor units corresponding to the operating switch states with optimized loss dynamic balancing based on the analysis results, as the optimal control scheme for the switching transistor units on each normal circuit path.

6. The loss balancing control system for an NPC circuit under single-switch fault as described in claim 5, characterized in that: The circuit monitoring module includes a synchronous data detection unit and a log update storage unit; The synchronization data detection unit includes a synchronization detection platform, which is an interactive visual management platform. The synchronization detection platform is associated with several sensor devices to collect the operating data of the switching transistor unit and the circuit path in the NPC path, and transmits the data to the visual interface for output through a signal network. The operating data of the switching transistor unit includes conduction voltage data, collector current data, and switching frequency. The operating data of the circuit path includes the output current data and output voltage data of the corresponding circuit path. The log update storage unit marks the real-time switching transistor operation data and circuit path operation data collected in the NPC circuit with the collection timestamp, respectively constructs the corresponding switching transistor unit periodic operation data set and circuit path periodic operation data set, and stores the log by setting the update period.

7. The loss balancing control system for an NPC circuit under single-switch fault as described in claim 6, characterized in that: The switching transistor fault analysis module includes a switching transistor fault location unit and a switching transistor loss analysis unit; The switching transistor fault location unit labels and locates the circuit path in the NPC circuit, and labels and locates the switching transistor unit on each circuit path; it retrieves the periodic operation data set of the corresponding switching transistor unit, analyzes the safety status and transition status of the corresponding switching transistor unit operation data in real time, and marks the faulty switching transistor unit with anomaly location based on the analysis results. The switching transistor loss analysis unit determines the location tag of the faulty switching transistor unit based on the analysis data of the faulty switching transistor unit, and retrieves the periodic operation data sets of normal switching transistor units and the periodic operation data sets of the faulty switching transistor unit in normal state, respectively, to analyze the loss data of the switching transistor unit during normal operation. The loss data of the switching transistor unit during normal operation includes the switching transistor unit's conduction loss and switching loss. Based on the analysis results of the loss data of each switching transistor unit during normal operation, the loss data of the circuit path corresponding to each switching transistor is analyzed.

8. The loss balancing control system for an NPC circuit under single-switch fault according to claim 7, characterized in that: The feedback control module includes a fault feedback unit and a control scheme output unit; The fault feedback unit provides feedback on the fault status of the switching transistor units on each circuit path in the NPC circuit through the visual interface of the synchronous detection platform. When a faulty switching transistor unit exists, the output unit of the control scheme outputs the optimal control scheme for the switching transistor unit based on the dynamic balance optimization analysis of the loss of each normal circuit path.

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