Torque Ripple Reduction Method of Switched Reluctance Motor Based on Five-Level Converter

Aimed at the problem of large torque ripple and low efficiency caused by the poor current tracking effect of switched reluctance motor (SRM), a torque ripple reduction method of switched reluctance motor based on a five-level converter is proposed. A novel five-level converter with A and C phases or B and D phases sharing the same bridge arm is designed. Compared with the traditional converter, the control is more flexible and the cost is lower. According to the nonlinear model of SRM, the conduction region is reclassified, and the phase output torque with a large inductance change rate is preferred to avoid excessive peak current at the beginning of commutation. Aimed at the problem of poor winding current tracking ability when the speed and load conditions change greatly, the direct instantaneous torque control (DITC) method based on the five-level converter is proposed, and the DITC conduction rules at low and high speeds are designed. According to the current speed, the torque error, and the rotor position, the appropriate conduction mode is selected to make sure that the motor can run stably at a low speed and the current can track the required value in time at a high speed, so as to realize the reduction of torque ripple. The simulation and experimental results show that compared with the traditional DITC, the control strategy can reduce the torque and current ripple in a wide speed range and improve the dynamic characteristic of the torque