Sensorless control of an interior permanent magnet synchronous motor based on an adaptive sliding mode observer using position error extraction method

In this paper, an adaptive observer based on sliding mode (AO-SM) for sensorless backstepping control of interior permanent magnet synchronous motor (IPMSM) is proposed. The adaptive observer based on sliding mode is designed using an extraction of rotor position estimation error and a parameter-free virtual dynamical model in order to estimate rotor position, speed and acceleration under a wide speed range, even very close to zero. Then, from the estimates obtained from the adaptive observer, these are implemented in a robust backstepping controller for tracking a desired speed reference, and a current-
$-i_{d}$
reference, which is computed by using a maximum-torque-per-ampere (MTPA) strategy. Furthermore, based on a Lyapunov approach an analysis of the convergence of observer and the system stability under control action is presented. Moreover, through a comparative experimental study among the proposed methodology and the one based on the injection of high frequency signals, the effectiveness of the proposed methodology is demonstrated.