An analysis of the accuracy of indirect shaft sensor for synchronous reluctance motor

The authors report a rotor position sensing technique for the SynRM (synchronous reluctance motor) which does not use any discrete position sensors. An accuracy analysis of the new indirect SynRM position sensing scheme is presented. The analysis breaks down the position error to the fundamental causes in the position sensing scheme. The individual sample error at the phase current zero crossings comes from the quantization error of the induced voltage and the quantization and the sampling rate errors of the phase current. It is shown that the present rotor sensor is adequate for ⩽1° accuracy in rotor position sensing during the extended zero crossing periods of the phase currents