A Novel Saturated Differential Inductance-Based Position Estimation and Sensorless Startup Control of Non-Salient DC Vernier Reluctance Machine

DC-excited Vernier reluctance machine (DC-VRM), exhibits the merits of small torque ripple and robustness structure, which has good potential to be applied as an aerospace starter generator. To achieve a sensorless startup with reliable position estimation for a non-salient DC-VRM, a novel saturated inductance differential-based saliency extraction position estimation method is proposed. By exploring the armature winding saturated differential inductance characteristics during field excitation, the inductance saliency is extracted from the different saturation degrees in the two sub-phase coils. Moreover, through reduced order inductance modeling, a linear inductance characteristic can be guaranteed for reliable position estimation. Consequently, the inductance modeling effort and the required memory size for data storage can be effectively reduced. The proposed method can effectively guarantee system reliability. The feasibility of the proposed method is verified by theoretical analysis and experiments.