Design Optimization And Analysis Of Novel Automotive Reverse Salient Pole Flux Controlled Permanent Magnet Motor

The research of energy vehicles(EV)is a necessary request for China to change from a large automotive country to a strong automotive country and is a key initiative for China to adjust to weather change and promote green development.As one of the important components of energy vehicles,the performance of the motor in terms of load carrying,speed,hill climbing,and maximum speed is an influential role in the loss and cost of the vehicle.At present,PMSM is extensive used in EV drive systems due to its better efficiency and easy control,but its further development is limited by the difficulty of air gap magnetic field adjustment and the risk of irreversible demagnetization of the permanent magnet when the magnet is weak.Based on this,a new Reverse Salient Pole Flux Controlled Permanent Magnet Motor(RSP-FCPM motor)is designed by combining the design concept of “Reverse Convex Pole and Flux Controlled” with the traditional permanent magnet motor,which can effectively improve the mentioned issues.In this article,the original structure is designed based on its principle,the flux control principle is further analyzed and a mathematical model is obtained for further study;the performance of the motor is optimized using a reasonable optimization solution,and the EM performance of the classical motor and the RSP-FCPM motor before and after optimization is analyzed;finally,a multi-physics field analysis of the motor is performed to confirm the reasonability and usefulness of the motor design.The main research contents and achieved results of this paper are as follows:(1)Design concept and operation mechanism analysis.The topology of the RSP-FCPM motor proposed in this paper is based on the conventional motor with effective segmentation of permanent magnets and reasonable setting of magnetic barriers to obtaining the characteristics of the reverse convex pole and flux control;then the running principle of the RSP-FCPM motor and the conditions of the way to control the flux are analyzed in coupled with the simplified magnetic circuit method,and at last,the mathematical model of the motor is deduced to build up for the follow-up control system research.(2)Rotor structure performance optimization.The complex rotor structure of the proposed RSP-FCPM motor is parametrically modeled and then optimally designed based on the optimization tool.Firstly,the optimization objective and its limitations are defined;then the single-parameter optimization of the PM segment size is carried out,and the optimal variates are determined after considering the amount of PM and rotor stresses;then the design variates are iteratively optimized by combining the MOGA algorithm with the stratified sensitivity calculate,the optimal value was obtained and the justification of the optimization method was confirmed by joint simulation.(3)Motor performance analysis.The basic EM characteristics,weak magnetic property and loss,efficiency of the conventional motor,and the optimized RSP-FCPM motor are analyzed based on simulation analysis.The analysis confirmed that the optimized RSP-FCPM motor has greater advantages in magnetizing range,inductance characteristics,no-load performance,and torque characteristics,and the output torque has been improved compared with that before optimization;the analysis of weak magnetic energy shows that the RSP-FCPM motor has wider speed range and constant power output area,and the performance in loss and efficiency is also better,which further confirms the validity of the optimization.(4)Multi-physics field analysis.To analyze and verify the bearing capacity of the rotor of the RSP-FCPM motor,the stresses,and deformations of the rotor during high-speed operation at ordinary and high temperatures were analyzed based on stress field simulation to confirm the structural safety of the rotor.Finally,the electromagnetic forces of the conventional motor and the RSP-FCPM motor under different operating conditions are simulated and analyzed and then coupled with the stator housing modal analysis to further analyze the vibration and noise of the two motors.