One-Instant Flux Observer design for Three-Phase induction motor with reduced bound active load rejection speed controller.

Abstract

Latency in flux observation has an adverse effect on the performance of observer-based field-oriented speed control for three-phase induction motor (IM). The reduction of the convergent rate of estimation errors could improve the performance of speed-controlled IM based on flux observers. The main contribution is to design a fast convergent flux observer, which provides bounded estimation error immediately after one instant of motor startup. The proposed flux observer fused barrier function adaptive mechanism with integral sliding mode control principle to yield BFISMO. Rigorous stability analysis has been conducted to achieve global flux estimation error ultimate boundedness. Moreover, three controllers have been designed. The first control design is devoted to flux control based on a backstepping controller, while the other two controllers' design is dedicated to rotor speed control of the motor. The speed controller is developed by combining the backstepping control with disturbance observers to estimate the unmatched load torque named quasi-sliding mode observer (QSMDO), and nonlinear disturbance observer (NLDO). Based on numerical simulations, the performance and efficacy of the proposed BFISMO have been assessed by conducting a comparison study to other observer techniques. The results showed the superiority of the proposed observer over the conventional versions.