Enhancement of Torque Pulsation and Acoustic Response in SRM Drives via Bipolar Excitation 2005-01-3468
This paper reports on the analytical and experimental results for an 8/6 switched reluctance machine operating under conventional and bipolar excitation strategies. The results illustrate the relationship between normal and tangential flux densities present in the airgap, and normal and tangential force densities present on stator and rotor poles. The investigation utilizes finite element analysis in conjunction with the Maxwell Stress Tensor method to correlate the relationship between the radial and tangential force densities and the airgap flux densities. In addition, finite element analysis is utilized to illuminate the difference in flux path type between the conventional and bipolar excitation methods. The experimental results are presented in terms of electromagnetic torque production over a full electrical cycle for each excitation method. The enhancement in mitigating torque ripple has a direct correspondence to the acoustic response due the improved magnetic balance that bipolar excitation provides.