Fault Diagnosis Based On Support Vector Machines Of Cascaded Inverter Power Units

With the popularity of the frequency control technique,the cascaded inverter has been largely used to drive pumps,fans,compressors and other large-scale mechanical equipments.It has been one of the important equipments of saving energy,transforming traditional industries,promoting technological innovation,which is prone to various failures.Therefore,it is quite neceserry for the depth study of it’s fault diagnosis.Firstly,this paper considers the power units of cascaded inverter as the study object.Based on the current development,structure,working principle of cascaded inverter,the simulation is established in the environment of MATLAB/Simulink.At the same time,the power tubes’ open circuit fault and bus filter electrolytic capacitors’ aging fault are simulated.By comparative analysis for the output signals under different fault conditions of cascade inverter,the characteristics law of various faults is summarized.And then the wavelet analysis is used to extract its fault feature to compose the feature vector as the training and testing samples of SVM.Secondly,this paper systematically introduces the related theories of SVM.LSSVM proposed based on SVM overcomes larger calculation and slower convergence of SVM and it’s basic principle and classification methods is introduced.Since LSSVM model is easily affected by regularization parameters and nuclear parameters,PSO algorithm is proposed to optimize the parameters of SVM,and its basic theory is also introduced.In order to improve the efficiency and accuracy of fault diagnosis,on the basis of PSO algorithm,an improved PSO(IPSO)is put forward to optimize LSSVM parameters.The simulation results show that IPSO-LSSVM model has faster convergence speed and classification accuracy in the application of fault diagnosis of the cascaded inverter.Finally,this paper designs a cascade inverter fault diagnosis system based on LabVIEW,and the system is effective to diagnosis the faults of the cascaded converter power units,which has a certain value in engineering.