Research On Influencing Factors And Control Suppression Of Rotor Eddy Current Loss Of High-speed Permanent Magnet Motor

High-speed permanent magnet brushless DC motor(PBLDCM)has the outstanding characteristics of high energy conversion efficiency,high stability and safety and reliability,which meets the needs of green,energy-saving and highefficiency industrial development in the new era of today’s country,and is now widely used in new energy sources.Automotive,aerospace and flywheel energy storage and many other fields.However,high-speed motors have large rotor eddy current losses due to the rotational speed several times that of ordinary motors,which may cause the temperature of part of the rotor to rise too quickly,resulting in the permanent magnets of the rotor being irreversible and losing magnetism at high temperatures.as a result of.Since the PBLDCM used for flywheel energy storage operates in a vacuum environment,the heat dissipation of the motor becomes more difficult,so it is of great value and significance to carry out the research on the rotor eddy current loss.This paper takes the PBLDCM for flywheel energy storage as the research object,and carries out relevant research on the eddy current loss of the motor rotor.The specific research contents are as follows:(1)According to the overall performance index of a certain type of flywheel energy storage system,the relevant design requirements of PBLDCM are clarified.According to the design theory of high-speed motor body,the design and calculation of the main structure of PBLDCM are completed,and the structural parameters of each component of the motor are preliminarily obtained..(2)The finite element model of PBLDCM is built by Maxwell software,and the electromagnetic analysis under no-load and load conditions is carried out respectively to obtain an intuitive understanding of the motor performance.The simulation results show that the design of the motor’s flux linkage meets the technical requirements,and the performance under load conditions has reached the established target,which lays a foundation for subsequent research.(3)The analytical formula for rotor eddy current loss of PBLDCM is analyzed and deduced.The analytical model comprehensively considers multiple eddy current reaction fields including harmonic current,and then the accuracy and effectiveness of the model are verified by the finite element method.(4)In view of the generation mechanism of eddy current loss of PBLDCM,the direct influence of three structural parameters of stator slot,air gap and rotor sheath on eddy current loss is considered.Under the finite element simulation analysis,the loss is compared by changing the relevant parameters.Research and determine the relationship between different influencing factors and rotor eddy current loss provides a reference for the structural optimization design of the motor.(5)From the perspective of rotor eddy current loss control intervention,a variable width current hysteresis control strategy that dynamically adjusts the hysteresis ring width according to the reference current amplitude signal is designed,and a control model of PBLDCM is built by using the Simulink platform,and the harmonic content and rotor eddy current loss under the constant width and variable width current hysteresis control are analyzed and compared through the joint simulation between Simulink and Maxwell,and the effectiveness of the control strategy on the suppression of eddy current loss is verified.