A mathematical torque ripple minimization technique based on nonlinear modulating factor for switched reluctance motor drives

Abstract

This paper presents a method to reduce the torque ripple in an 8/6 4-phase switched reluctance motor. The proposed scheme introduces a nonlinear modulating factor dependent on the rotor position and magnitude of the phase currents. This factor manipulates the currents in two adjacent phases during commutation and reduces the torque ripple effectively. Unlike conventionally available torque sharing functions (TSF), the proposed method instantaneously modulates every phase current obtained mathematically based on the other phase current in order to maintain the net torque constant. The proposed method requires minimal offline analysis and offers maximum possible torque with minimal ripple. The method is simple and easy to implement due to less computational burden. The proposed algorithm is implemented using Matlab/Simulink software and is also validated experimentally on a 0.6 hp 8/6 SRM using an FPGA-based hardware setup developed in the laboratory. Typical results are presented and compared with existing techniques. A torque ripple of ≈ 8% has been achieved.