A high-order sliding mode stator flux observer for asynchronous motor based on feedback linearization

This paper proposes a high-order sliding mode stator flux estimation method for asynchronous motor based on feedback linearization. Selecting the rotor flux as the system´s output, the coordinate change matrix and the nonlinear state feedback are derived based on the affine nonlinear model of asynchronous motors by using the nonlinear system´s differential geometry theory. Then the asynchronous motor system is input-output linearized and the feedback linearization model of asynchronous motors is obtained. On this basis, a high-order sliding mode rotor flux observer for asynchronous motor is designed to estimate rotor flux, and this paper analysis the stability of the designed observer, then we can calculate stator flux by using the rotor flux. The designed observer is applied to Direct Torque Control (DTC) of the asynchronous motor and achieves a good control performance. Simulation results verify the effectiveness and feasibility of the proposed method.