Research On Low Torque Ripple Control Method For Switched Reluctance Motor

Switched reluctance motor(SRM)is a kind of nove motor which developed rapidly in the 1980's,and it is widely concerned for its simple and solid structure,high reliability,low manufacturing cost,high efficiency,etc.However,due to its inherent time-varying,strong coupling,non-linear characteristics,it is difficult to obtain excellent performance with traditional control methods,there is a large torque ripple during operation,which limits the application and promotion of SRM in many fields.In order to reduce the torque ripple and improve the performance of the SRD,in this paper,the low torque ripple control algorithm for SRM is researched.Firstly,the basic structure,working principle and mathematical model of SRM are introduced,the mathematical model is simplified by linear and quasi-linear analytical methods.The finite element analysis of SRM is carried out by Jmag software,and flux and torque characteristic curves of SRM are obtained,based on the results of finite element analysis,the nonlinear simulation model of SRM is established in Matlab/Simulink.Secondly,the basic principle of direct torque control(DTC)algorithm and its implementation on SRM are introduced,the influence of the basic voltage vectors on the variation of the flux linkage and the torque is analyzed in detail.The mechanism of torque ripple in the commutation region under the traditional DTC algorithm is deeply studied.By revising the sector space,increasing the space voltage vector,and redesigning the switch table,a DTC algorithm based on switch table optimization is proposed to reduce torque ripple in the commutation region.The current chopper control,the traditional DTC algorithm and the improved DTC algorithm are simulated by Matlab/Simulink respectively.The simulation results show that the improved DTC algorithm can suppress the torque ripple in the commutation region effectively and reduce the negative torque of each phase to some extent.Thirdly,angle control is added to the basis of DTC to restrict the energization region of each phase,the direct instantaneous torque control(DITC)algorithm can reduce the negative torque effectively,but there are problems that large torque ripple and large current peak in the commutation region.Based on the traditional DITC algorithm,by optimizing the turn-on angle online,and according to the torque-ampere-ratio of the outgoing phase and the incoming phase in commutation region to choose their switching state,a high efficiency torque ripple suppression method is proposed for switched reluctance motor.The traditional DITC algorithm and the improved DITC algorithm are simulated by Matlab/Simulink respectively,the simulation results show that the improved DITC algorithm can suppress the torque ripple while optimizing the phase current waveform.Finally,the hardware-in-the-loop(HIL)testing platform based on RT-LAB and TMS320F28335 controller is introduced.The performances of the current chopper control of the SRD and the traditional DTC algorithm,the improved DTC algorithm,the traditional DITC algorithm,and the improved DITC algorithm are compared with the HIL test.The test results verify the correctness and effectiveness of the proposed low torque ripple control algorithm for SRM.