A Comparison Between Nonlinear Kalman Filters for Sensorless Induction Motor Drives

This paper presents a comparison between nonlinear Kalman filters for estimation in Sensorless induction motor drive applications. The extended Kalman filter (EKF), square-root unscented Kalman filter (SRUKF), and square root cubature Kalman filter (SRCKF) are considered. Each filter's performance is tested under dynamic and steady state conditions. Observability of each filter's state-space model is performed and analyzed. Sensorless direct torque control is utilized. Simulation and experimental results are presented to show superiority of both SRUKF and SRCKF when compared to EKF.