A new algorithm for indirect position estimation in permanent magnet AC motors

One of the principal expected benefits of the indirect position estimation techniques in permanent magnet (PM) ac motors is the operating at zero, low and higher speeds. This paper present a new algorithm that estimates the rotor position of PM ac motors indirectly using the phase voltages and the currents that are accessible at the output of the motor's inverter. The results presented in the paper demonstrates that the algorithm developed here has several advantages over the previous methods: simple, mathematically less computational (hence suitable in practical applications), robust (less sensitive to the parameter deviations and measurement errors), not dependent upon the back EMF and excitation current profiles, and operates from standstill up to the high speeds.