Research On Torque Ripple And Its Minimization Method Of Switched Reluctance Motor

It is well known that switched reluctance motor(SRM)has a series of excellent characteristics such as low cost,high relibility,low maintenance workload,wide range of speed regulation,high system efficiency and low system failure rate which should be an ideal speed control motor system.However,the severe torque ripple,vibration and noise of SRM limit the wide application.A large number of scholars had carried out many useful researches on the minimization of SRM torque ripple,theoretically,many methods had been proposed to reduce the torque ripple,but most of them still stayed in the theoretical simulation stage,or only solved the torque ripple caused by one certain factor.Some of these mothods also had got certain effects,however,it was not still perfect for reducing the torque ripple from the whole motor system so that the torque ripple is still quite obvious by experiments mearsurement for SRM speed control system.Therefore,this paper proposes a new method which is peak-valley complementary principle to minimize the torque ripple of SRM.Through this method,two sets of SRD with the same electromagnetic parameters are rotated in the same speed and direction so that their average torque is superimposed on the output to drive load,and the phase difference of their torque ripple waveforms is 180 degrees electric angle,whicih can effectively offset and minimize the torque ripple by the complementarity of peak and valley value.This method is clear in principle,easy to control and easy to implement,and is able to suppress the torque ripple from the whole motor system.The specific research contents are as follows:(1)Firstly,this paper analyzes the structure of SRM body and its operating principle,then,discribes the waveform of electromagnetic torque under the condition of three typical current waveform and the characteristic torque ripple.On this basis,the method to measure the torque ripple of SRM is proposed.Then the experimental measurement platform is built based on this method,which obviously proves the objectivity and existence of the torque ripple in SRM output torque.(2)The characteristics and the method to minimize the torque ripple of SRM are studied and analyzed.Then the method based on peak-valley complementary is proposed to suppress and minimize the torque ripple,that is to say,the average torque of two same sets of SRD is superimposed on the output to drive load,and the phase difference of their torque ripple waveforms is 180 degrees electric angle,which can effectively offset and minimize the torque ripple by the complementarity of peak and valley value.(3)Based on SIMULINK simulation platform,the model of two sets of SRM whose torque ripple waveform are 180 degrees electric angle phase difference is built,which prove the feasibility of this method.On this basis,an experimental platform of SRM system with low torque ripple is built,which is constituted by two SRM with the mutually offsetting torque ripple.(4)On the test platform of SRM system based on peak-valley complementary method to suppress and minimize torque ripple,this paper systematically researched the effect of this SRM system minimizing the torque ripple,and has achieved very obvious suppression effect Finally,a novel SRM with low torque ripple is proposed.