Torque Ripple Suppression By Stator-Rotor Tooth Shape Optimization Of Switched Reluctance Motors

As the environmental and energy problems become more and more prominent,developing electric vehicles instead of fuel vehicles becomes an effective way to solve this problem.As the energy conversion device of electric vehicle,the motor determines the overall dynamic performance of the vehicle.Switched reluctance motor has the characteristics of stable operation,simple structure and wide speed range,which is suitable for the needs of electric vehicles.However,the inherent structure characteristics and current excitation mode of switched reluctance motor can lead to serious torque ripple problems,so the research on the suppression of motor torque ripple has become a hot spot in the research of switched reluctance motor.In this paper,an optimization scheme of stator and rotor tooth profile is proposed to reduce the torque ripple by reducing the edge flux and magnetic circuit saturation,This method can be used as a reference for the research of torque ripple suppression of switched reluctance motor.The main research contents of this paper are as follows:Firstly,the structure and operation mode of switched reluctance motor and the operation principle of speed regulation system are introduced.A theoretical calculation analysis is carried out according to the power demand parameters of electric vehicles,and the theoretical power parameters and structural dimensions of switched reluctance motors for electric vehicles are derived.According to the working principle of switched reluctance motor and the operation mode of drive system,a model of nonlinear switched reluctance motor drive system is established.The drive system adopts the current chopper control strategy.Secondly,a finite element model for electromagnetic simulation of the motor is established,and the causes of torque pulsation due to mechanical structure of the switched reluctance motor are analyzed,and an optimized model is proposed to compare and select the best optimized dimensional parameters.By simulating the conventional model and the proposed optimized model,the magnetic line distribution,flux density distribution and static characteristic curves of each model are obtained,and the effects of the optimized model structure on the internal electromagnetic field of the motor and the output characteristics of the motor are compared and analyzed.The theoretical models obtained are proved to be reasonable.The results of phase currents and output torques of each model are compared by drive system simulation analysis,and the effectiveness of the proposed optimization scheme is verified.Then,based on the common driving conditions of electric vehicles,each model under the conditions of different speed,load and phase current opening interval was simulated,the torque ripple rate of each model was calculated,and the comparative analysis was carried out,and the influence of speed,load and phase current opening interval on the traditional motor and the optimized motor model was obtained,and the effectiveness of the optimization model was further verified.Finally,the simulation results of the output torque ripple obtained by each model under the combination conditions of different speeds,loads and phase current opening intervals were evaluated comprehensively.By comparing the torque ripple of the optimized model and the traditional model under various conditions,the effectiveness of the optimized fixed and rotor tooth profile on the torque ripple suppression of switched reluctance motor was fully verified.