New absolute rotor-position sensors for inverter-driven motors

A new type of variable-reluctance (VR) resolver is presented for rotor-position sensing. This VR resolver is realized by varying airgap reluctance in certain waveform. Without winding on rotor and with only simple winding patterns on stator, and without structure constrains on size as in conventional resolvers, this resolver can be designed into compact size and is suitable to be integrated into PMSM or brushless motors. Sample testings show that the errors between standard sine-wave and the resolver outputs are within 1%, position error is within 2.3E-3 RAD.