Speed sensorless control of induction motor using sliding mode observer with variable boundary layer

The vector control in the speed and torque controlled ac drive is typically implemented through measuring the rotor speed or position. However, speed and position sensors require the additional mounting space, reduce the reliability in harsh environments and increase the cost of a motor. Therefore, many studies have been performed for the elimination of speed and position sensors. This paper investigates an improved sliding mode observer for the speed sensorless control of an induction motor. The proposed control strategy is the sliding mode observer with a variable boundary layer for a low-chattering and fast-response control. Simulation and experimentation have been performed to verify the proposed control algorithm.