Compound fault diagnosis method for clamping diodes and supporting capacitors of inverter

Abstract

The invention discloses a compound fault diagnosis method for clamping diodes and supporting capacitors of an inverter. The method comprises the following steps: establishing a three-level inverter compound fault model through simulation software; respectively acquiring three-phase current signals on an output side of the inverter under the normal working conditions and under the condition of each compound fault, carrying out decomposition of three-phase currents under each condition through EMD, and constructing fault feature vectors by using correlation coefficients as fault features; carrying out normalization processing of the fault feature vectors, inputting each normalized feature vector as a training sample into an SVM classifier for training, and optimizing SVM parameters through the genetic algorithm, so as to obtain trained SVM classifiers; and acquiring inverter fault signals to be diagnosed during a testing phase, constructing the fault feature vectors through the same method, inputting the fault feature vectors into the trained SVM classifiers for testing, and outputting fault diagnosis results.

Description

technical field [0001] The invention relates to a composite fault diagnosis method for inverter clamping diodes and supporting capacitors, belonging to the field of fault diagnosis of power electronic devices. Background technique [0002] The multi-level converter is a new type of converter that realizes high-voltage and high-power output by changing the topology of the converter itself. It does not need a buck-boost circuit and a voltage-balancing circuit. Compared with two-level inverters, multi-level inverters have the advantages of low power switch voltage stress, power device series voltage equalization, low harmonic content of output voltage waveform, small electromagnetic interference problems, small switching losses and high work efficiency. Therefore, inverters with this structure are widely used in high-voltage, high-current, and high-power fields, such as Japan's 700-series Shinkansen, Shanghai Maglev trains, and Harmony CRH trains. The most typical of the multi...

AI Technical Summary

Problems solved by technology

There are 12 IGBT power transistors, 6 clamping diodes and 2 DC support capacitors in the three-level inverter. IGBT fault diagnosis methods have been proposed in many literatures. However, the combined fault diagnosis of clamping diodes and support capacitors method is seldom proposed

In fact, due to the harsh working environment of the inverter, this composite fault is likely to occur

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