Input-output feedback linearization control of Induction motor with adaptive backstepping observer

This paper presents a direct-torque control and stator flux control scheme for a three-phase Induction motor which is supplied by a Field Programmable Gate Array (FPGA)-based two level Space Vector Modulation (SVM) voltage-source inverter. Using the three-phase Induction Motor (IM) model in a stationary (a, b) axis reference frame with stator currents and stator flux as state variables, an Ideal Feedback Linearization Control (IFLC) is first adopted to decouple the motor generated torque and the norm of stator flux. Then in order to increase the robustness of the drive system control against the motor resistance variations and uncertainties, an adaptive backstepping observer is designed that provides the simultaneous estimation of the above parameters and stator flux. Using the Lyapunov theory, a full proof for convergence of states is presented together with stability proof for the parameter estimates. Finally, the effectiveness and validity of the proposed control approach is demonstrated by both the simulated and experimental results.