Position estimation in induction machines utilizing rotor bar slot harmonics and carrier frequency signal injection

This paper presents a simple and robust way of utilizing harmonic saliencies for the estimation of rotor position. A carrier frequency voltage excitation is used to produce a carrier frequency current, which contains the desired spatial information. A closed-loop, tracking observer is then used to estimate the rotor position. Due to its reliance on a spatial saliency and carrier frequency signal injection, the technique is very robust over a wide speed range, including low and zero speed.