A new closed-loop converter for sinusoidal encoders — Preliminary results

Sinusoidal position transducers provide accurate and reliable representation of the mechanical position of their shafts. The sine/cosine transducers signals may be used in open loop or closed loop arrangements for the determination of position. The present work describes a novel implementation of the classical PLL closed loop method without using VCO, DAC, counter and look-up tables. The proposed method makes use of the excitation signal of the resolver to estimate the sine/cosine of the estimated angle. The proposed method is simpler than the available techniques, and may be implemented easily using digital or basic analogue electronic circuitry. Beside simplicity of implementation, the proposed schemes offer the advantage of robustness to amplitude fluctuation of the transducer excitation signal. This paper describes the concept of the new method, simulation results and preliminary experimental results.