Optimized Current Regulator Design for Induction Motor Dynamic Performance Improvement in Over-Modulation Region

Over-modulation region operation can ensure high utilization of DC-link, which can extend the speed range and output torque capability for induction motor (IM) drives. However, the maximum voltage and current constrains inevitably degrade the dynamic performance of the system. To achieve fast current response, this paper presents an optimized current regulator structure. First, a feedforward resistance PI current regulator (FFRPI) is proposed. Then, the anti-integral item is added into the controller to further improve the dynamic performance. Moreover, to reduce the impact of digital control delay in over modulation region, the dual-sampling dual-update modulation method is adopted combined with Tustin discretization method. Compared with the conventional PI control and feedforward PI (FFPI) control, the proposed approach can improve the dynamic performance of current regulator. Finally, the effectiveness of the proposed method is verified by the simulation and experimental results.