Hybrid-Excited Variable Reluctance Resolver With Wide Speed Range

The accuracy of the variable reluctance resolver (VR-Resolver) highly depends on the rotational speed and its rotational speed range is limited by the frequency of the excitation signal. To eliminate the mentioned performance dependency, this paper proposes a hybrid-excited VR-Resolver (HVR-Resolver) with two separate sets of excitation windings: a toroidal excitation winding for the AC excitation supply and an on-tooth one for the DC excitation supply. Similar to the conventional method, the HVR-Resolver is working with AC excitation ON and DC excitation OFF at the low-speed range. For high-speed operation, the excitation switched from AC excitation to DC. By using this technique, the proposed HVR-Resolver is able to accurately estimate the position at a wide speed range. This feature makes the HVR-Resolver an outstanding candidate for EV applications. The proposed design is simulated using time-stepping finite element analysis (TSFEA) in order to study the performance at both low-speed and high-speed ranges with different rotor pole numbers. In addition, an optimization process is conducted to find the best rotor shape factors. The experimental test on the proposed HVR-Resolver indicates a close agreement between simulation and experimental results.