Loss equalization control method and system for NPC circuit under single switch tube fault

Abstract

The invention discloses a loss equalization control method and system for an NPC circuit under a single switch tube fault, and relates to the technical field of data analysis, and the method comprises the steps: carrying out the real-time operation data collection of a switch tube unit and a circuit path in the NPC circuit through building a synchronous detection platform, and carrying out the periodic log storage; each switch tube unit in the NPC circuit is positioned, and fault analysis is carried out; based on the switch tube fault analysis data, positioning a circuit path where a fault switch tube is located, and performing loss redistribution analysis on each circuit path by analyzing NPC circuit loss data; according to the loss redistribution data on each circuit path in the NPC circuit, performing loss dynamic equalization optimization analysis in combination with a corresponding circuit path operation switch state, and outputting a control scheme of a corresponding circuit path switch tube according to an analysis result; according to the invention, the output performance of the NPC circuit with the fault of the single switch tube is ensured, and the circuit loss balance is autonomously controlled at the same time.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of data analysis, in particular to a loss balancing control method and system for NPC circuit under single switch tube failure. BACKGROUND

[0002] The NPC circuit is a neutral point clamped three-level circuit, which is a typical multi-level power electronic topology structure and is widely used in new energy power generation, motor drive and other fields. In the application of the NPC circuit in the existing environment, the path related to the switch tube will fail after the single switch tube failure, and the remaining devices need to bear additional consumption to keep the circuit running, which easily leads to local overheating or secondary failure. In the traditional fault control method, the focus is on monitoring the normal operation circuit, and it is difficult to balance the circuit output performance and loss balancing control after the switch tube failure. The control means for fault occurrence in the existing means is to sacrifice efficiency for stability, and lacks dynamic adjustment capability. SUMMARY

[0003] The purpose of the present application is to provide a loss balancing control method and system for NPC circuit under single switch tube failure to solve the problems in the prior art.

[0004] To achieve the above purpose, the present application provides the following technical scheme: The loss balancing control method for NPC circuit under single switch tube failure comprises the following steps: Real-time operation data of switch tube units and circuit paths in the NPC circuit are collected by building a synchronous detection platform, and periodic log storage is performed according to the collected data; Each switch tube unit in the NPC circuit is positioned, and the periodic operation data of the corresponding switch tube unit are called to perform fault analysis. Based on the switch tube failure analysis data, the circuit path where the fault switch tube is located is positioned, and loss redistribution analysis is performed on each circuit path by analyzing the NPC circuit loss data; According to the loss redistribution data of each circuit path in the NPC circuit, the loss dynamic balancing optimization analysis is performed in combination with the operation switch state of the corresponding circuit path, and the control scheme of the switch tube of the corresponding circuit path is output according to the analysis result.

[0005] Further, the synchronization detection platform is an interactive visual management platform, which collects switch tube unit operation data and circuit path operation data in the NPC path by a plurality of sensor devices, and transmits the data to a visual interface for data output through a signal network; wherein the switch tube unit operation data includes conduction voltage data, collector current data, and switching frequency; the circuit path operation data includes output current data and output voltage data corresponding to the circuit path; wherein the sensor devices include current sensors and voltage sensors, which are respectively used to collect current data and voltage data of the switch tube unit and the circuit path operation; a counter device is used to record the switch tube switching frequency data; The switch tube operation data and the circuit path operation data collected in real time in the NPC circuit are marked by combining with a collection timestamp, and a corresponding switch tube unit cycle operation data set and a circuit path cycle operation data set are constructed, and log storage is performed by setting an update cycle; wherein the log storage by setting the update cycle is specifically that an update cycle length is set by manual setting, when the collection cycle length meets the update cycle length, the switch tube operation data and the circuit path operation data collected in the current collection cycle are stored in the database as historical data, and new cycle data collection is performed.

[0006] Further, the circuit paths in the NPC circuit are respectively labeled and positioned, and the switch tube units on each circuit path are respectively labeled and positioned; the label positioning refers to labeling the bridge arms in the NPC circuit and the switch tube units on the corresponding circuit paths, and positioning the circuit paths according to the labels; the corresponding switch tube unit cycle operation data set is called, the safety state and the jump state of the corresponding switch tube unit operation data are analyzed in real time, and according to the analysis result, the abnormal positioning mark of the fault switch tube unit is performed; wherein the safety state analysis of the switch tube unit operation data is to compare the operation data at each time point in the switch tube unit cycle operation data set with the safety interval of the corresponding operation data, if it is within the safety interval, it is determined that the operation data at the corresponding time point is normal, otherwise it is determined to be abnormal; the jump state analysis of the switch tube unit operation data is to compare the absolute value of the difference between the operation data at adjacent time points in the switch tube unit cycle operation data set with the safety threshold value of the corresponding operation data, if it is less than or equal to the safety threshold value, it is determined that the operation data at adjacent time points is normal, otherwise it is determined to be abnormal; wherein the safety interval and the safety threshold value are set by human; wherein the switch tube unit fault includes open circuit and short circuit; According to the fault switch tube unit analysis data, the fault switch tube unit positioning label is determined, and according to the switch tube unit cycle operation data set, the normal switch tube unit cycle operation data set and the cycle operation data set of the fault switch tube unit in the normal state are respectively called to analyze the loss data of the normal operation of the switch tube unit; The loss data of the normal operation of the switch tube unit includes the on-state loss of the switch tube unit and the switch loss of the switch tube; Its calculation formula is ; Wherein, P con,k is the on-state loss of the switch tube unit corresponding to the label k; V k is the on voltage of the switch tube unit corresponding to the label k; I k is the collector current of the switch tube unit corresponding to the label k; D k is the on duty ratio of the switch tube unit corresponding to the label k; ; Wherein, P sw,k is the switch loss of the switch tube unit corresponding to the label k; f k is the cycle switching frequency of the switch tube unit corresponding to the label k; E on is the on energy of the switch tube unit corresponding to the label k; E off is the off energy of the switch tube unit corresponding to the label k; Wherein the on duty ratio, on energy and off energy of the switch tube unit can be obtained from the device data stored in the database; According to the analysis result of the loss data of the normal operation of each switch tube unit, the loss data of the circuit path corresponding to each switch tube is analyzed respectively; Its calculation formula is ; Wherein, P sy,G is the total loss of the circuit path corresponding to the label G; P con,G is the on-state loss of the circuit path corresponding to the label G; P sw,G is the switch loss of the circuit path corresponding to the label G; Wherein the on-state loss of the corresponding circuit path is the sum of the on-state losses of each switch tube unit on the circuit path; The corresponding circuit path switch loss is the sum of the switch losses of each switch tube unit on the circuit path.

[0007] Further, based on the loss analysis data of the switch tube unit under the normal operation of each circuit path, the switch tube unit with the fault existing at present is located, and the circuit path where the fault switch tube unit is located is determined, and the fault circuit path is marked; Combined with the loss data of the fault circuit path and the loss data of the normal circuit path, the remaining normal circuit path loss redistribution analysis of the NPC circuit is carried out; Its specific analysis and calculation is ; Wherein, total loss of the circuit path with label G in the normal circuit path set after the redistribution; total loss of the circuit path with label G in the normal circuit path set before the redistribution; switching frequency of the switch tube unit with label k on the circuit path with label G in the normal circuit path set; f all sum value of the switching frequency of the switch tube unit on each circuit path in the normal circuit path set; total loss of the circuit path with label G in the fault circuit path set before the redistribution; wherein HG is the normal circuit path set, YG is the fault circuit path set; the normal circuit path set contains the remaining normal circuit path labels except the fault circuit path; the fault circuit path set contains the fault circuit path label; Based on the normal circuit path loss redistribution analysis data, by corresponding to the number of existing operation switch states on each normal circuit path and constructing the corresponding operation switch state set, the conduction state combination of each switch tube unit on the corresponding normal circuit path of each operation switch state is determined; the loss dynamic balance optimization analysis of the circuit path under each operation switch state in the operation switch state set of each normal circuit path is analyzed, and the conduction state combination of the switch tube unit corresponding to the operation switch state with the optimal loss dynamic balance is output as the optimal control scheme of the switch tube unit on the corresponding normal circuit path according to the analysis result; wherein, the specific analysis of the loss dynamic balance optimization analysis of the circuit path under each operation switch state corresponding to each normal circuit path is, ; wherein, loss dynamic balance optimization analysis index of the operation switch state with label Y in the operation switch state set corresponding to the circuit path with label G in the normal circuit path set; output current of the circuit path with label G in the normal circuit path set; output voltage of the circuit path with label G in the normal circuit path set; I c and V c respectively corresponding to the reference current and reference voltage of the circuit path with label G in the normal circuit path set; P HG sum value of the total loss of each circuit path in the normal circuit path set after the redistribution; α1, α2 and α3 are artificial preset weight coefficients; based on the analysis result of the loss dynamic balance optimization analysis index of the circuit path under each operation switch state in the operation switch state set corresponding to each circuit path in the normal circuit path set, the operation switch state corresponding to the minimum value is the optimal operation switch state of the corresponding circuit path, and the conduction state combination of each switch tube unit on the corresponding circuit path is the optimal control scheme of the switch tube unit.

[0008] Further, the fault state of the switch tube unit on each circuit path in the NPC circuit is fed back through the visual interface of the synchronous detection platform. When there is a faulty switch tube unit, an optimal control scheme of the switch tube unit for dynamic loss balance optimization analysis of each normal circuit path is output.

[0009] The loss balance control system of the NPC circuit under single switch tube failure, the system comprises a circuit supervision module, a switch tube failure analysis module, a balance control analysis module and a feedback control module; The circuit supervision module collects real-time operation data of the switch tube unit and the circuit path in the NPC circuit through the synchronous detection platform, and stores the periodic log according to the collected data; the switch tube failure analysis module locates each switch tube unit in the NPC circuit, and retrieves the periodic operation data of the corresponding switch tube unit for failure analysis; the balance control analysis module locates the circuit path where the faulty switch tube is located based on the switch tube failure analysis data, and analyzes the loss data of the NPC circuit to redistribute the loss of each circuit path; according to the analysis data, the control scheme of the corresponding circuit path switch tube is determined by loss dynamic balance optimization analysis combined with the operating switch state of the corresponding circuit path; the feedback control module feeds back the faulty switch tube on each circuit path and outputs the control scheme of the corresponding circuit path switch tube.

[0010] Further, the circuit supervision module comprises a synchronous data detection unit and a log update storage unit; The synchronous data detection unit comprises a synchronous detection platform, which is an interactive visual management platform; the synchronous detection platform is associated with a plurality of sensor devices, collects the operation data of the switch tube unit and the operation data of the circuit path in the NPC path, and transmits the data to the visual interface through a signal network for data output; wherein the switch tube unit operation data includes on voltage data, collector current data and switching frequency; the circuit path operation data includes output current data and output voltage data of the corresponding circuit path; The log update storage unit marks the real-time collected switch tube operation data and circuit path operation data in the NPC circuit with a collection timestamp, respectively constructs the corresponding switch tube unit periodic operation data set and circuit path periodic operation data set, and stores the log through setting the update period.

[0011] Further, the switch tube failure analysis module comprises a switch tube failure positioning unit and a switch tube loss analysis unit; The switch tube fault positioning unit respectively labels the circuit paths in the NPC circuit and labels the switch tube units on each circuit path; the corresponding switch tube unit cycle operation data set is called, the safety state and the jump state of the corresponding switch tube unit operation data are analyzed in real time, and according to the analysis result, the abnormal positioning mark of the fault switch tube unit is performed; The switch tube loss analysis unit determines the fault switch tube unit positioning label according to the fault switch tube unit analysis data, and respectively calls the normal switch tube unit cycle operation data set and the cycle operation data set of the fault switch tube unit in a normal state according to the switch tube unit cycle operation data set, analyzes the loss data of the normal operation of the switch tube unit; the loss data of the normal operation of the switch tube unit includes the on-state loss of the switch tube unit and the switching loss of the switch tube; according to the analysis result of the loss data of the normal operation of each switch tube unit, the loss data of each circuit path corresponding to the switch tube is analyzed.

[0012] Further, the balanced regulation analysis module includes a path loss redistribution unit and a loss balanced optimal analysis unit. The path loss redistribution unit determines the fault switch tube unit and the circuit path where the fault switch tube unit is located based on the loss analysis data of the switch tube unit under normal operation on each circuit path, and marks the fault circuit path; the remaining normal circuit path loss redistribution analysis of the NPC circuit is performed by combining the loss data of the fault circuit path and the loss data of the normal circuit path. The loss balanced optimal analysis unit determines the conduction state combination of each switch tube unit on each normal circuit path corresponding to each job switch state based on the normal circuit path loss redistribution analysis data, by constructing a corresponding job switch state set according to the number of existing job switch states on each normal circuit path, and analyzes the loss dynamic balanced optimization analysis of each normal circuit path in the job switch state set; according to the analysis result, the conduction state combination of the switch tube unit corresponding to the job switch state with the optimal loss dynamic balanced optimization is output as the optimal regulation scheme of the switch tube unit on each normal circuit path.

[0013] Further, the feedback regulation module includes a fault feedback unit and a regulation scheme output unit. The fault feedback unit feeds back the fault state of the switch tube unit on each circuit path in the NPC circuit through the visual interface of the synchronous detection platform; The regulation scheme output unit outputs the optimal regulation scheme of the switch tube unit of the loss dynamic balanced optimal analysis of each normal circuit path when there is a fault switch tube unit.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention combines a sensor device to construct a monitoring platform to realize circuit data collection, fault location analysis, loss balancing control analysis and solution output when a single switch tube fault occurs in an NPC circuit, thereby realizing dynamic control of circuit loss in the NPC circuit when a single switch tube state occurs. It realizes the autonomous control of circuit loss when the NPC circuit is in the state of a single switch tube by redistributing the loss of the normal circuit when a fault occurs, and based on this, performs loss balancing optimization analysis on the operating state of each circuit, and outputs the optimal switch tube control combination according to the optimization analysis, thereby ensuring the output performance of the NPC circuit with a single switch tube fault while achieving autonomous control of the circuit loss balance. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the structure of the loss balancing control system of the NPC circuit under a single switch tube fault of the present invention; Figure 2 Schematic diagram of the flow of the loss balancing control method of the NPC circuit under a single switch tube fault of the present invention. DETAILED DESCRIPTION

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0017] Example: Figure 1 As shown, the present invention provides a technical solution: A loss-balancing control system for an NPC circuit under a single switch failure, wherein the system includes a circuit supervision module, a switch failure analysis module, a balance control analysis module, and a feedback control module; Among them, the circuit supervision module collects real-time operating data of the switch tube units and circuit paths in the NPC circuit by building a synchronous detection platform, and stores periodic logs based on the collected data; the switch tube fault analysis module locates each switch tube unit in the NPC circuit and retrieves the periodic operating data of the corresponding switch tube unit for fault analysis; the balancing control analysis module locates the circuit path where the faulty switch tube is located based on the switch tube fault analysis data, and performs loss redistribution analysis on each circuit path by analyzing the NPC circuit loss data; based on the analysis data and the corresponding circuit path operating switch status, a loss dynamic balancing optimization analysis is performed to determine the control plan for the switch tube of the corresponding circuit path; the feedback control module provides feedback to the faulty switch tube on each circuit path and outputs the control plan for the switch tube of the corresponding circuit path.

[0018] Further, the circuit supervision module includes a synchronous data detection unit and a log update storage unit; The synchronous data detection unit includes a synchronous detection platform, which is an interactive visual management platform; wherein the synchronous detection platform is associated with a plurality of sensor devices, collects switch tube unit operating data and circuit path operating data in the NPC path, and transmits the data to a visual interface for data output through a signal network; wherein the switch tube unit operating data includes turn-on voltage data, collector current data, and switching frequency; the circuit path operating data includes output current data and output voltage data corresponding to the circuit path; The log update storage unit marks the real-time collected switch tube operating data and circuit path operating data in the NPC circuit with a collection timestamp, respectively constructs a corresponding switch tube unit cycle operating data set and a circuit path cycle operating data set, and stores logs by setting an update cycle.

[0019] Further, the switch tube fault analysis module includes a switch tube fault positioning unit and a switch tube loss analysis unit; The switch tube fault positioning unit respectively labels and positions the circuit paths in the NPC circuit, and respectively labels and positions the switch tube units on each circuit path; respectively calls the corresponding switch tube unit cycle operating data set, analyzes the safety state and jump state of the corresponding switch tube unit operating data in real time, and according to the analysis result, marks the abnormal position of the fault switch tube unit; The switch tube loss analysis unit determines the fault switch tube unit positioning label according to the fault switch tube unit analysis data, and respectively calls the normal switch tube unit cycle operating data set and the cycle operating data set of the fault switch tube unit in a normal state according to the switch tube unit cycle operating data set, analyzes the loss data of the normal operation of the switch tube unit; the loss data of the normal operation of the switch tube unit includes the on-state loss of the switch tube unit and the switching loss of the switch tube; according to the analysis result of the loss data of the normal operation of each switch tube unit, the loss data of the circuit path where each switch tube is located is analyzed.

[0020] Further, the balanced regulation analysis module includes a path loss redistribution unit and a loss balanced optimal analysis unit; The path loss redistribution unit is based on the loss analysis data of the normal operation of the switch tube unit on each circuit path, locates the switch tube unit currently having a fault, determines the circuit path where the fault switch tube unit is located, and marks the fault circuit path; combines the loss data of the fault circuit path and the loss data of the normal circuit path, and analyzes the loss redistribution of the remaining normal circuit paths of the NPC circuit; The loss balance optimal analysis unit is based on normal circuit path loss redistribution analysis data, determines the conduction state combination of each switch tube unit on each normal circuit path corresponding to each job switch state by corresponding to the number of existing job switch states on each normal circuit path and constructing a corresponding job switch state set, analyzes the loss dynamic balance optimization analysis of each circuit path in each job switch state set, and outputs the switch tube unit conduction state combination corresponding to the loss dynamic balance optimization job switch state as the optimal regulation and control scheme of the switch tube unit on each normal circuit path according to the analysis result.

[0021] Further, the feedback regulation module includes a fault feedback unit and a regulation scheme output unit. The fault feedback unit feeds back and prompts the fault state of the switch tube unit on each circuit path in the NPC circuit through the visual interface of the synchronous detection platform. The regulation scheme output unit outputs the optimal regulation and control scheme of the switch tube unit of the loss dynamic balance optimization analysis of each normal circuit path when there is a fault switch tube unit. As shown in the accompanying drawings, Figure 2 The present application provides another technical scheme: The loss balance control method of the NPC circuit under single switch tube fault, the method comprising the following steps: Through the synchronous detection platform, real-time operation data of the switch tube unit and the circuit path in the NPC circuit are collected, and periodic log storage is performed according to the collected data; Each switch tube unit in the NPC circuit is positioned, and the periodic operation data of the corresponding switch tube unit is called to perform fault analysis; based on the switch tube fault analysis data, the circuit path where the fault switch tube is located is positioned, and loss redistribution analysis of each circuit path is performed by analyzing the loss data of the NPC circuit; According to the loss redistribution data of each circuit path in the NPC circuit, the loss dynamic balance optimization analysis is performed in combination with the corresponding circuit path job switch state, and the control scheme of the switch tube of the corresponding circuit path is output according to the analysis result.

[0022] Further, the synchronous detection platform is an interactive visual management platform, which collects the running data of the switch tube unit and the running data of the circuit path in the NPC path by a plurality of sensor devices associated with the switch tube unit, and transmits the data to the visual interface for data output through a signal network; wherein the running data of the switch tube unit includes conduction voltage data, collector current data, and switching frequency; the running data of the circuit path includes output current data and output voltage data corresponding to the circuit path; wherein the sensor device includes a current sensor and a voltage sensor, which are respectively used to collect the current data and voltage data of the running switch tube unit and circuit path; a counter device is used to record the switching frequency data of the switch tube. The running data of the switch tube and the running data of the circuit path collected in real time in the NPC circuit are marked with a collection timestamp, and a corresponding switch tube unit cycle running data set and a circuit path cycle running data set are constructed, and log storage is performed through setting an update cycle; wherein the log storage through setting an update cycle is specifically that the length of the update cycle is set by hand, and when the collection cycle length meets the update cycle length, the switch tube running data and the circuit path running data collected in the current collection cycle are stored in the database as historical data, and new cycle data collection is performed.

[0023] Further, the circuit paths in the NPC circuit are respectively labeled and positioned, and the switch tube units on each circuit path are respectively labeled and positioned; the label positioning refers to assigning labels to the bridge arms in the NPC circuit and the switch tube units on the corresponding circuit paths, and positioning the circuit paths according to the labels; the corresponding switch tube unit cycle running data set is called, the safety state and the jump state of the corresponding switch tube unit running data are analyzed in real time, and according to the analysis result, the abnormal positioning mark of the fault switch tube unit is performed; wherein the safety state analysis of the switch tube unit running data is to compare the running data at each time point in the switch tube unit cycle running data set with the safety interval of the corresponding running data, if it is within the safety interval, it is determined that the running data at the corresponding time point is normal, otherwise it is determined to be abnormal; the jump state analysis of the switch tube unit running data is to compare the absolute value of the difference between the running data at adjacent time points in the switch tube unit cycle running data set with the safety threshold of the corresponding running data, if it is less than or equal to the safety threshold, it is determined that the running data at adjacent time points is normal, otherwise it is determined to be abnormal; wherein the safety interval and the safety threshold are set by human; wherein the switch tube unit fault includes open circuit and short circuit; According to the fault switch tube unit analysis data, the fault switch tube unit positioning label is determined, and according to the switch tube unit cycle operation data set, the normal switch tube unit cycle operation data set and the cycle operation data set of the fault switch tube unit in the normal state are respectively called to analyze the loss data of the normal operation of the switch tube unit; The loss data of the normal operation of the switch tube unit includes the on-state loss of the switch tube unit and the switch loss of the switch tube; Its calculation formula is ; Wherein, P con,k is the on-state loss of the switch tube unit corresponding to the label k; V k is the on voltage of the switch tube unit corresponding to the label k; I k is the collector current of the switch tube unit corresponding to the label k; D k is the on duty ratio of the switch tube unit corresponding to the label k; ; Wherein, P sw,k is the switch loss of the switch tube unit corresponding to the label k; f k is the cycle switching frequency of the switch tube unit corresponding to the label k; E on is the on energy of the switch tube unit corresponding to the label k; E off is the off energy of the switch tube unit corresponding to the label k; Wherein the on duty ratio, on energy and off energy of the switch tube unit can be obtained from the device data stored in the database; According to the analysis result of the loss data of the normal operation of each switch tube unit, the loss data of the circuit path corresponding to each switch tube is analyzed respectively; Its calculation formula is ; Wherein, P sy,G is the total loss of the circuit path corresponding to the label G; P con,G is the on-state loss of the circuit path corresponding to the label G; P sw,G is the switch loss of the circuit path corresponding to the label G; Wherein the on-state loss of the corresponding circuit path is the sum of the on-state losses of each switch tube unit on the circuit path; The corresponding circuit path switch loss is the sum of the switch losses of each switch tube unit on the circuit path.

[0024] Further, based on the loss analysis data of the switch tube unit under the normal operation of each circuit path, the switch tube unit with the fault existing at present is located, and the circuit path where the fault switch tube unit is located is determined, and the fault circuit path is marked; Combined with the loss data of the fault circuit path and the loss data of the normal circuit path, the remaining normal circuit path loss redistribution analysis of the NPC circuit is carried out; Its specific analysis and calculation is ; Wherein, total loss of the circuit path with label G in the normal circuit path set after the redistribution; total loss of the circuit path with label G in the normal circuit path set before the redistribution; switching frequency of the switch tube unit with label k on the circuit path with label G in the normal circuit path set; f all sum value of the switching frequency of the switch tube unit on each circuit path in the normal circuit path set; total loss of the circuit path with label G in the fault circuit path set before the redistribution; wherein HG is the normal circuit path set, YG is the fault circuit path set; the normal circuit path set contains the remaining normal circuit path labels except the fault circuit path; the fault circuit path set contains the fault circuit path label; Based on the normal circuit path loss redistribution analysis data, the existing number of job switch states on each normal circuit path is determined by constructing the corresponding job switch state set, and the conduction state combination of each switch tube unit on the corresponding normal circuit path of each job switch state is determined; the loss dynamic balance optimization analysis of the circuit path under each job switch state of each normal circuit path is analyzed, and the conduction state combination of the switch tube unit corresponding to the job switch state with the optimal loss dynamic balance is output as the optimal control scheme of the switch tube unit on the corresponding normal circuit path according to the analysis result; wherein, the specific analysis of the loss dynamic balance optimization analysis of the circuit path under each job switch state of each normal circuit path is, ; wherein, loss dynamic balance optimization analysis index of the job switch state with label Y in the job switch state set corresponding to the circuit path with label G in the normal circuit path set; output current of the circuit path with label G in the normal circuit path set; output voltage of the circuit path with label G in the normal circuit path set; I c and V c respectively correspond to the reference current and reference voltage of the circuit path with label G in the normal circuit path set; P HG sum value of the total loss of each circuit path in the normal circuit path set after the redistribution; α1, α2 and α3 are artificial preset weight coefficients; based on the analysis result of the loss dynamic balance optimization analysis index of the circuit path under each job state in the job switch state set corresponding to each circuit path in the normal circuit path set, the job state corresponding to the minimum value is the optimal job state of the loss dynamic balance of the corresponding circuit path, and the conduction state combination of each switch tube unit on the corresponding circuit path is the optimal control scheme of the switch tube unit; In this embodiment, the operating switch state of the NPC circuit is determined by the on / off combination of the switch tubes on each circuit path, and each operating switch state corresponds to the action logic of a specific switch tube.

[0025] Furthermore, the fault status of the switch tube units on each circuit path in the NPC circuit is fed back through the visual interface of the synchronous detection platform; When there is a faulty switch tube unit, the optimal control scheme of the switch tube unit is output based on the dynamic balance optimization analysis of the loss of each normal circuit path.

[0026] 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 embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A loss balancing control method for an NPC circuit under a single switch failure, characterized by: The method comprises the following steps: By building a synchronous detection platform, real-time operation data of the switch tube units and circuit paths in the NPC circuit is collected, and periodic log storage is performed based on the collected data; By locating each switch unit in the NPC circuit and retrieving the cycle operation data of the corresponding switch unit for fault analysis; based on the switch tube fault analysis data, the circuit path where the faulty switch tube is located is located, and by analyzing the NPC circuit loss data, loss redistribution analysis is performed on each circuit path; Based on the loss redistribution data on each circuit path in the NPC circuit, combined with the operating switch status of the corresponding circuit path, a loss dynamic balance optimization analysis is performed, and the control plan for the corresponding circuit path switch tube is output based on the analysis results.

2. The method for controlling loss balancing of an NPC circuit under a single switch failure according to claim 1, wherein: The synchronous detection platform is an interactive visual management platform that collects the operating data of the switch tube units and the circuit path in the NPC path through a number of sensor devices, and transmits the data to a visual interface through a signal network for data output. The operating data of the switch tube units includes the on-state voltage data, the collector current data, and the switching frequency; the operating data of the circuit path includes the output current data and the output voltage data of the corresponding circuit path. The switch tube operation data and circuit path operation data collected in real time in the NPC circuit are marked with the collection timestamp, and the corresponding switch tube unit cycle operation data set and circuit path cycle operation data set are constructed respectively, and log storage is performed by setting the update cycle.

3. The method for controlling loss balancing of an NPC circuit under a single switch failure according to claim 2, wherein: In the NPC circuit, the circuit paths are individually labeled and located, and the switch tube units on each circuit path are also individually labeled and located. The corresponding switch tube unit periodic operation data sets are retrieved and the safety status and transition status of the corresponding switch tube unit operation data are analyzed in real time. Based on the analysis results, the faulty switch tube unit is abnormally located and marked. Determine the location tag of the faulty switch tube unit based on the analysis data of the faulty switch tube unit, and retrieve the normal switch tube unit periodic operation data set and the normal periodic operation data set of the faulty switch tube unit based on the periodic operation data set of the switch tube unit, and analyze the loss data of the normal operation of the switch tube unit; the loss data of the normal operation of the switch tube unit includes the on-state loss of the switch tube unit and the switching loss of the switch tube; Based on the analysis results of the loss data of the normal operation of each switching tube unit, the loss data of the circuit path corresponding to each switching tube is analyzed respectively.

4. The method for controlling loss balancing of an NPC circuit under a single switch failure according to claim 3, wherein: Based on the loss analysis data of the normal operation of the switch tube units on each circuit path, the faulty switch tube unit is located, the circuit path where the faulty switch tube unit is located is determined, and the faulty circuit path is marked; Combine the loss data of the fault circuit path with the loss data of the normal circuit path to perform loss redistribution analysis on the remaining normal circuit paths of the NPC circuit; Based on the loss redistribution analysis data of normal circuit paths, by corresponding to the number of operating switch states existing on each normal circuit path and constructing a corresponding operating switch state set, the conduction state combination of each switch tube unit on the normal circuit path corresponding to each operating switch state is determined; in the operating switch state set of each normal circuit path, the loss dynamic balance optimization analysis of the circuit path under each operating switch state is analyzed, and according to the analysis results, the conduction state combination of the switch tube unit corresponding to the operating switch state with the most optimized loss dynamic balance is output as the optimal control scheme for the switch tube unit on each normal circuit path.

5. The method for controlling loss balancing of an NPC circuit under a single switch failure according to claim 4, wherein: Through the visual interface of the synchronous detection platform, the fault status of the switch tube unit on each circuit path in the NPC circuit is fed back; When there is a faulty switch tube unit, the optimal control scheme of the switch tube unit is output based on the dynamic balance optimization analysis of the loss of each normal circuit path.

6. A loss-balancing control system for an NPC circuit under a single switch failure, characterized by: The system includes a circuit supervision module, a switch tube fault analysis module, a balance control analysis module and a feedback control module; The circuit supervision module collects real-time operating data of the switch tube units and circuit paths in the NPC circuit by building a synchronous detection platform, and performs periodic log storage based on the collected data; the switch tube fault analysis module locates each switch tube unit in the NPC circuit and retrieves the periodic operating data of the corresponding switch tube unit for fault analysis; the balancing control analysis module locates the circuit path where the faulty switch tube is located based on the switch tube fault analysis data, and performs loss redistribution analysis on each circuit path by analyzing the NPC circuit loss data; a loss dynamic balancing optimization analysis is performed based on the analysis data and the operating switch status of the corresponding circuit path to determine the control scheme for the switch tube of the corresponding circuit path; the feedback control module provides feedback to the faulty switch tube on each circuit path and outputs the control scheme for the switch tube of the corresponding circuit path.

7. The loss-balancing control system for an NPC circuit under a single switch failure according to claim 6, characterized in that: The circuit supervision module includes a synchronous data detection unit and a log update storage unit; The synchronous data detection unit includes a synchronous detection platform, which is an interactive visual management platform. The synchronous detection platform is connected by a number of sensor devices, collects the operating data of the switch tube unit and the circuit path in the NPC path, and transmits the data to the visual interface through the signal network for data output. The switching tube unit operating data includes the on-state voltage data, the collector current data, and the switching frequency; the circuit path operating data includes the output current data and the output voltage data of the corresponding circuit path. The log update storage unit marks the switch tube operation data and circuit path operation data collected in real time in the NPC circuit in combination with the collection timestamp, constructs the corresponding switch tube unit periodic operation data set and circuit path periodic operation data set respectively, and performs log storage by setting the update cycle.

8. The loss-balancing control system for an NPC circuit under a single switch failure according to claim 7, characterized in that: The switch tube fault analysis module includes a switch tube fault location unit and a switch tube loss analysis unit; The switch tube fault location unit locates the circuit paths in the NPC circuit and the switch tube units on each circuit path; retrieves the periodic operation data sets of the corresponding switch tube units, analyzes the safety status and transition status of the corresponding switch tube unit operation data in real time, and marks the faulty switch tube units for abnormal location based on the analysis results; The switch tube loss analysis unit determines the faulty switch tube unit location tag based on the faulty switch tube unit analysis data, and retrieves the normal switch tube unit periodic operation data set and the faulty switch tube unit periodic operation data set in a normal state according to the switch tube unit periodic operation data set, and analyzes the loss data of the normal operation of the switch tube unit; the loss data of the normal operation of the switch tube unit includes the on-state loss of the switch tube unit and the switching loss of the switch tube; based on the analysis results of the loss data of the normal operation of each switch tube unit, the loss data of the circuit path corresponding to each switch tube is analyzed respectively.

9. The loss-balancing control system for an NPC circuit under a single switch failure according to claim 8, characterized in that: The balance control and analysis module includes a path loss redistribution unit and a loss balance optimal analysis unit; The path loss redistribution unit locates the currently faulty switch tube unit based on the loss analysis data of the switch tube units under normal operation on each circuit path, determines the circuit path where the faulty switch tube unit is located, and marks the faulty circuit path; Combine the loss data of the fault circuit path with the loss data of the normal circuit path to perform loss redistribution analysis on the remaining normal circuit paths of the NPC circuit; The loss balancing optimal analysis unit is based on the loss redistribution analysis data of the normal circuit path. By corresponding to the number of operating switch states existing on each normal circuit path and constructing a corresponding operating switch state set, it determines the conduction state combination of each switch tube unit on the normal circuit path corresponding to each operating switch state; analyzes the loss dynamic balancing optimization analysis of the circuit path under each operating switch state in the operating switch state set of each normal circuit path, and outputs the conduction state combination of the switch tube unit corresponding to the operating switch state with the most optimized loss dynamic balancing according to the analysis results as the optimal control scheme for the switch tube unit on each normal circuit path.

10. The loss balancing control system for an NPC circuit under a single switch failure according to claim 9, 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 switch tube units on each circuit path in the NPC circuit through the visual interface of the synchronous detection platform; When there is a faulty switch tube unit, the control scheme output unit outputs an optimal control scheme for the switch tube unit based on a dynamic balanced optimization analysis of the losses of each normal circuit path.

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