Sensorless control of interior permanent magnet machine drives with zero-phase-lag position estimation

This paper presents an improved method to estimate rotor motion states for an interior permanent magnet machine drive. This approach is based on the estimation of the saliency-based EMF in a stationary reference frame using a state filter. The spatial information obtained from the estimated saliency-based EMF is used in an observer to estimate the motor motion states. By adding the commanded torque as a feedforward input to the observer, the motion state estimation has zero phase-lag, providing a very high bandwidth estimate.