Research On Electromagnetic Interference Characteristics And Modeling Method Of Permanent Magnet Synchronous Motor

With the application of various high-frequency power electronic devices,electromagnetic interference has become a serious problem in electromechanical devices.As the core equipment of various drive systems,permanent magnet synchronous motors have many complicated coupling paths and their physical structure is complicated.So the research on electromagnetic interference has always been a difficult point in the field.In this paper,the electromagnetic interference characteristics and modeling methods of permanent magnet synchronous motors are studied in order to provide guidance for the prediction of electromagnetic interference of motors.The main work is as follows:(1)Analysis of electromagnetic interference characteristics of permanent magnet synchronous motor.Switching device IGBT is the source of electromagnetic interference of the whole motor system.Firstly,the mechanism of its interference is analyzed.Based on this,the influence law of it about electromagnetic interference on the motor system is studied.The electromagnetic interference mechanism and characteristics of three-phase cable and DC cable as interference propagation paths are analyzed.The coupling path and interference type of the motor body are analyzed,and the electromagnetic interference coupling path diagram of the whole motor system is established.(2)Research on modeling method of low frequency electromagnetic interference for permanent magnet synchronous motor.Take the existing permanent magnet synchronous motor as an example for disassembly and measurement.The motor modeling is realized by Ansoft Maxwell software.The finite element simulation method is used to obtain the approximate magnetic field distribution of the motor in space.According to the existing national low-frequency electromagnetic field related test standards,the relevant experimental schemes are formulated,and the low-frequency magnetic field probe is used to perform the measurement of the magnetic field in the space.Finally,the simulation and experimental results are compared to verify the correctness of the simulation modeling method.(3)Research on modeling method of high frequency electromagnetic interference for permanent magnet synchronous motor.Two different modeling methods are proposed for the motor body.One is the black box equivalent circuit model based on the vector fitting method,and the corresponding zero-pole parameters are obtained according to the calculated parameters.The equivalent circuit parameters are used to construct the high-frequency equivalent circuit model of the motor;the other is the equivalent circuit model based on the finite element electromagnetic field simulation calculation.The electromagnetic field simulation calculation is used to extract the parasitic parameters of the motor at high frequency,according to the specific structure of the motor.A high-frequency circuit model of the motor is built.Finally,the feasibility of the two modeling methods is verified by experiments and their respective applicable conditions are analyzed.