Selection of Excitation Signal Waveform for Improved Performance of Wound-Rotor Resolver

Wound-Rotor (WR) resolvers are similar to two-phase synchronous generators. Their difference is related to the excitation signal. While DC voltage is used for exciting synchronous generator, high frequency AC voltage is employed for that of resolver. The common waveform for excitation signal of resolver is sinusoidal voltage. However, preparing the high frequency sinusoidal voltage in the resolver to digital converter (RDC) is always a challenge. Therefore, in this paper different high frequency AC waveforms are applied as the excitation signal of the resolver and the estimated position, resulted from RDC, is discussed. The aim of this work is to find an appropriate excitation waveform that ensures the high accuracy operation of resolver beside the simple implementation possibility for RDC. Output analogue voltages are obtained using time stepping finite element analysis. Then, the amplitude modulated (AM) signals are imported to the MATLAB where two demodulation techniques are compared for calculating the voltages' envelope and the position error. Finally, experimental measurements validate the simulation results.