Position Sensorless Control of a Permanent Magnet Stepping Motor Based on Sliding Mode Observer

Abstract This paper deals with a position sensorless control of a permanent magnet stepping motor. The proposed controller is designed to reduce the studied actuator oscillations and overshoot which can induce an erratic working. As the mechanical solutions are expensive and cumbersome, the control ones are considered to be the most suitable. Closed loop control of these motors offers significant performance advantages. But, the use of position sensors complicates the drive design and its control system. To avoid the use of position sensors which are costly and cumbersome, we propose in this paper a sliding mode observer allowing the estimation of the motor position from the statoric voltages and currents. It is proven that a sliding mode observer is robust against observed systems parametric uncertainties and well adapted to a large variety of nonlinear systems such as electrical motors. The performances of the sensorless position proportional derivative controller and the robustness of the sliding mode observer are tested by numerical simulations. The obtained results show the efficiency of the proposed control law.