Research On The Restrain Of Switched Reluctance Motors’ Torque Ripple

In recent years, with development of power electronics and microprocessor technology, the switched reluctance motor drive systems (SRD) received wide attention of scholars both domestic and abroad. It has the characteristics of simple maintenance, high reliability, low cost and wide speed range, which make SRM applied in a great number in aerospace, automotive and other harsh fields. However, many disadvantages restrain the further application, such as torque ripple during rotation. Although the traditional control can perform well in speed and torque control, yet the torque ripple remains in considerable amplitude.This research mainly concentrated on the restrain of torque ripple, and at first it set up a mathematical model of SRM. But due to the nonlinearity and coupling in SRM, the magnetic characteristics cannot be precisely described by linear equations or coordinate transformation. Thus, the fast modeling method was applied, which used the measured data. Then it used DTC to restrain the torque ripple, which is widely used in AC drive, and it also chose the voltage vectors to control based on the SRM characters. DTC can effectively reduce the fluctuation of torque which proved by the simulation using Matlab/simulink. But DTC of SRM produced pretty large negative torque during roration. This would restrict the application of DTC.On the basis of DTC, the Direct Instantaneous Torque Control (DITC) takes turn-on and turn-off angle into consideration to reduce the negative torque. It controlled torque directly using different hysteresis torque controller. Then it added Torque Sharing Function into the control to optimized the reference. The results proved the given method. Then the influence of turn-off angle upon efficiency was discussed, that the optimal turn-off angle could maximize the efficiency, in spite of the difficulties in finding the function between angle and efficiency. The optimal turn-off angle could be got though experiment to set up a look-up table for use.The test platform was established, whose drive unit used a7.5kW12/8SRM and load used an eddy current dynamometer. It applied asymmetry half bridge structure, and TMS320F28335was adopted to process the control. At last, the performance of SRM and the results of comparation experiments between DITC and VC were given.