Research And Implementation Of Fault Diagnosis For Permanent Magnet Synchronous Motor Of Pure Electric Vehicle

Permanent magnet synchronous motor(PMSM),characterized by high efficiency,high power density,low loss and etc,is the primary power source of pure electric vehicles.The effective fault diagnosis of PMSM constitutes one of the key technologies for vehicle control unit(VCU).Firstly,the VCU functions of electric vehicles are divided,and their fault diagnosis function module is analyzed;the common fault tree diagram of PMSM is given.Secondly,the working mechanism of PMSM is analyzed,and the vector control mathematical model of PMSM is established.The common electrical fault phenomena as well as the fault output are simulated by using Matlab/simulink and Ansys.Thirdly,the fault features of each fault type are extracted by using the wavelet decomposition,and then joint fault diagnosis is conducted by using BP and Elman neural networks.Finally,using VCU as the fault diagnosis function platform and ISO15765 protocol as the standard to set the fault diagnosis code format,the simulation module is embedded into VCU by using ControlBase,so as to realize fault diagnosis.The characteristics of this research are as follows:(1)The proportional change relationship between the q-axis current and electromagnetic torque is obtained through making full use of the vector control mode of the motor I_d=0;(2)BP and Elman artificial neural networks are used to make up for mutual shortcomings and improving the accuracy;(3)The fault code message is designed based on the current international mainstream ISO15765 protocol of electric vehicles,and the more convenient and fast simulation model code conversion technology is used.Through the technology of simulation model programmatic embedding,the original development cycle of pure code are effectively shortened.The diagnostic results also prove the feasibility of the system.Servicemen can locate the PMSM fault phenomena quickly and accurately through the diagnosis system.