Optimization Design Of Switched Relunctance Motor For Torque Ripple Suppression

Switched reluctance motor(SRM)has ordinary and robust structure,high starting torque,independent operation of each phase and flexible control mode compared with the traditional asynchronous motors,which is suitable for a variety of applications,especially in extreme environments with higher reliability and fault tolerance.However,due to the special structure of SRM,a large torque ripple is usually generated during its operation,which leads to noise and vibration.Therefore,it is necessary to restrain the torque ripple of SRM to expand its application range.This paper focuses on the design,structural optimization and control parameters optimization of a three-phase12/8 pole SRM.Firstly,based on the related theories and design principles of SRM,the structural parameters of initial model of SRM are designed.The basic structure and working principle of SRM are briefly described,and its basic equations and linear mathematical models are sorted out in detail.Based on the above theoretical analysis of SRM and the design theory of basic structural parameters,the initial structural parameters of the three-phase 12/8 pole SRM were obtained,and the finite element simulation was carried out based on Ansoft software.Secondly,according to the output torque characteristics of the initial model,an improved structural scheme for the stator and rotor pole of SRM is proposed and optimized.Based on the finite element simulation results of the initial SRM,the reasons for the large torque ripple of SRM are analyzed.In view of the reasons,a novel topology of the stator and rotor salient poles is proposed and the parametric analyses of main design parameters of the new topology are are carried out.In order to reduce the torque ripple rate(TRR)and improve the average torque,the surrogate models of the optimization goals are set up based on enough sample data from the finite element analysis and the Pareto genetic algorithm is adopted to conduct a multi-objective optimization for design parameters of the new topology.Then,the fuzzy set theory is used to select the best solution from the Pareto solution set.Comparing the output performances of the SRM obtained from topology optimization with the initial SRM,it is proved that the new structure can reduce the output torque ripple rate by 53.3%.Finally,on the basis of structural optimization,a complete driving system is established and the related control parameters in the system are optimized.For the SRM obtained by topology optimization,the simulink model of switched relunctance driver(SRD)with current chopper control(CCC)is established in MATLAB/Simulink,founding that adjusting the turn-on angle and turn-off angle in the control system can alleviate the fluctuation of the resultant torque during the phase commutation of SRM.Then,the turn-on angle and turn-off angle are taken as the optimization parameters to carry out the above multiobjective optimization process,and the most suitable turn-on and turn-off angles are obtained.By comparing the output characteristics of SRD system before and after the optimization of control parameters,it can be found that the optimized system can further reduce the output TRR by 39.7% without affecting the average torque on the basis of the motor structure optimization,which verifies the feasibility of the optimization of control parameters.