Position Estimation of AC Machines at all Frequencies using only Space Vector PWM based Excitation

This paper considers the position estimation in shaft sensorless AC motor drives over the entire speed range, including zero frequency. A method is described which is based on the standard fundamental wave space vector PWM excitation sequence and requires neither an observer based model nor a signal injection test signal. The method is verified by experimental results. The paper gives a comparison of the proposed method with other PWM excitation based methods for estimating the rotor position of AC machines.