Design and analysis of a decoupling current controller for induction machine

This paper analyzes the characteristics of current controllers for vector-controlled AC motors. In synchronous reference frame, the existence of cross-coupling, which increases with the synchronous frequency, impairs the behavior of torque response. System vibration and instability can occur if the current controller does not properly compensate the coupling and delays between the sampling of signals and PWM output. To overcome these problems, a decoupling current control scheme is proposed based on a more accurate induction machine model. The time-delay and corresponding compensation strategy are also studied in this paper. Simulation and experimental results are provided to show the improved dynamic performance of the proposed current controller.