Multi-Physics Design And Analysis Of Multi-Excitation Double-Stator Switched Flux Motor

In recent years,new energy vehicles with energy saving and emission reduction features have gradually become the development direction of future automobiles.Rare earth permanent magnet motors,as the main type of driving motors for new energy vehicles,have the advantages of high power and high efficiency.However,the price of rare earth permanent magnet materials fluctuates greatly and the relationship between supply and demand is tense,which increases the manufacturing costs of rare earth permanent magnet motors.Therefore,little rare earth or even non-rare earth permanent magnet motors have been widely concerned by scholars in the traction field.In this paper,a new structure of little rare earth multi excitation double-stator switched flux motor(abbreviated as MEDSF)is proposed.Deep and systematic multi-objective optimization and performance analysis based on multi-physical fields of electromagnetic-thermal-stress is applied.Firstly,combine the research of little rare earth motor,switched flux motor and double-stator motor with motor design requirements in automotive driving system,and a new topology of multi excitation double-stator switched flux motor is proposed.The operation principle and flux regulation principle are then analyzed.The main motor dimensions are determined,including the number of poles and slots,the size of two kinds of PMs and the ratio of winding turns according to the design criteria of traditional switched flux motor.Secondly,a parameterized motor model is established,and the output torque,torque ripple and efficiency are selected as optimization objectives on account of the motor' s performance indices.The key dimensional parameters are screened out with parameter sensitivity analysis method.The influence of key parameters on motor performance is analyzed with response surface method.The multi-objective genetic algorithm based on above results is applied to find Pareto optimum solution to structural parameters.At the same time,combined with the centrifugal stress and deformation distribution in the stress field,the rotor' s dimensions are further optimized,and finally the optimal model is obtained.Thirdly,in view of the complex operating conditions of new energy electric vehicles,the multi-physical field coupling analysis of MEDSF motor is carried out.In addition to conventional electromagnetic performance,considering that the ferrite in the motor can easily be demagnetized,the anti-demagnetization performance of the motor under different loads is simulated and analyzed.The magnetic field regulation ability and constant power speed range of the motor are then studied.Besides,the cost and utilization rate of PMs are calculated.Finally the simulation analysis of mechanical stress and deformation distribution and temperature field is employed to validate the design rationality and operation reliability of the proposed motor.Fourthly,a processing scheme is given,and the principle prototype is still in progress.Subsequently,the basic performance of the prototype will be tested to verify the correctness of the motor design and its optimization.