Integrating Sensing Coil Function into Field Winding for Initial Position Estimation of Nonsalient DC Vernier Reluctance Machine

This letter presents a novel mutual inductance detection method by integrating sensing coil function into field winding for the initial position estimation of nonsalient DC-excited vernier reluctance machines (DC-VRM). The key is to reutilize the field winding as a sensing coil by operating the power transistor states, and then the induced currents can be detected from the closed sensing coil when detection pulses are injected into the armature windings. Combined with the established mutual inductance model, reliable position estimation is easily achieved without additional detection circuits. The proposed method has good potential to be applied to a group of nonsalient machines with independent field and armature windings.