Open-circuit fault diagnosis method of three-phase four-wire system inverter transistor

Abstract

The invention discloses an open-circuit fault diagnosis method of a three-phase four-wire system inverter transistor. The open-circuit fault diagnosis method can realize rapid and highly robust diagnosis of an open-circuit failure of the three-phase four-wire system inverter transistor without adding additional sampling and hardware circuits. The open-circuit fault diagnosis method only requires existing information on a control system, and has small calculation amount, thereby avoiding the increase of additional hardware circuits and software burden; the open-circuit fault diagnosis method takes a deviation of a bridge arm midpoint voltage average value as a diagnosis variable, and can realize rapid diagnosis, so that the diagnosis time is shortened into a sampling cycle; the open-circuitfault diagnosis method adopts an error self-adoptive diagnosis threshold value, can guarantee high robustness without sacrificing a diagnosis speed; in addition, the open-circuit fault diagnosis method can be applied to a three-phase four-wire system inverter capable of energy bidirectional transmission and the like.

Description

technical field [0001] The invention belongs to the technical field of fault diagnosis of power electronic equipment, and in particular relates to a method for diagnosing an open circuit fault of a three-phase four-wire inverter transistor. Background technique [0002] Three-phase four-wire inverters have been widely researched and applied in the fields of active filtering, new energy grid connection, uninterruptible power supply, etc. Therefore, it is of great significance to improve the reliability of three-phase four-wire inverters; fault tolerance is a It is an effective measure to improve the operating life of the converter, and fast and accurate fault diagnosis is the premise of fault-tolerant operation. Industry surveys show that in power electronic converters, transistors are listed as one of the most prone to failure components. Therefore, many researches on fault diagnosis are aimed at transistors, and open-circuit faults of transistors are common faults of transi...

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Problems solved by technology

[0006] Current-based methods are diagnosed by directly analyzing and processing various current signals in the inverter, such as methods based on current traces (patent application number 201611111173.6), methods based on current phase and amplitude characteristics (patent application number 201611106907.1) , the method based on the effective value of the phase current (patent application number 201610532252.8), etc.; the advantage of this type of method is that it requires fewer signals and is simple to implement, but it takes a long time to diagnose, and usually cannot be used for inverters with bidirectional energy transmission

[0007] The model-based method is to diagnose by establishing a circuit model and using information such as voltage, current, and control variables in the inverter to calculate specific diagnostic variables for diagnosis, such as the diagnostic method based on output power (patent application No. 201310148901.0), based on the observed current The method of residual error (patent application number 201310743597.4), etc.; the diagnosis speed and robustness of this type of method still need to be improved

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