Analytical Modeling of Airgap Fields in Mutually Coupled Switched Reluctance Machine With Tangential Field Consideration

Mutually coupled (MC) switched reluctance machines (SRMs) have attracted considerable interest due to their lower torque ripple and reduced vibration compared to conventional SRMs. Accurate analytical modeling of radial and tangential airgap fields is critical for the initial design and harmonic source analysis of MCSRMs. However, the conventional SRM analytical model is not suitable for predicting airgap fields of MCSRMs due to their different winding configurations. Therefore, an analytical model is proposed in this paper to predict the airgap fields of MCSRMs, in which the tangential field and nonzero time-dependent magnetomotive force (MMF) are all accounted for. The model distinguishes the effect of armature winding, as well as single- and bilateral-magnetic-salient structure, on airgap field harmonics, facilitating root cause analysis of these harmonics. Furthermore, the average torque, torque ripple, radial and tangential electromagnetic force density of MCSRMs under non-saturation condition can be quickly predicted. The model is validated with two 12 stator-slot/8 rotor-slot MCSRMs through finite element simulation and experimental test.