Research On Fault Diagnosis Method For Power Electronics Rectifier

With rapid development of power electronics technology, power electronics rectifier of realizing energy conversion, because of its efficient, flexible and convenient control, easy to achieve and so on, make its application widespread increasingly. The fault problems of the power electronics rectifier are more and more prominent at the same time, therefore applies the automatic fault diagnosis technology in the power electronics rectifier has its practical significance and the economical significance, it is particularly important that the relevant theoretical and methodological research.The topic takes the development and improvement of power electronics rectifier fault intelligent diagnosis method as a goal. Against features extraction and diagnosis of two key technology in fault diagnosis for power electronics rectifier has conducted further research and analysis. The main research work completed as follows:Fault diagnosis method for power electronics rectifier based on PCA-Neural Network was proposed. First extract the feature vector from the fault signal with the principal component analytic (PCA) method, and then use neural network training and testing. Experimental result of thyristor open circuit fault diagnosis in power electronics rectifier showed that this method can simplify the structure of the neural network, improve the training speed of the network, have obtained very good diagnostic effect.Putting forward method that using wavelet packet analysis theory to carry on the characteristic from the fault signal of power electronics rectifier, extract its energy as input vector of fault classifier, carries on the classification and the diagnosis by the fault classifier to each kind of fault. Has confirmed this method validity through twelve pulse controlled rectifier thyristor open circuit fault diagnosis simulation result.Proposes fault diagnosis method for power electronics rectifier based on the SVM. An improved multi-fault SVM classification algorithm were studied, put forward fault diagnosis method for power electronics rectifier based on the SVM with ideal of the algorithm. Indicated through twelve pulse controlled rectifier thyristor open circuitfault diagnosis experimental result, this method can quite accurately diagnosis fault, and the diagnostic precision is high;Comparison with BP neural network, this method efficient and have a good outreach capacity under small-sample. It has the very good practical value in the solution to fault question for power electronics rectifier and the application prospect.