Tube-based robust current control of induction motors

Abstract

This paper develops a current controller for the induction motor (IM) to improve the control robustness against parameter variations, which are mainly caused by the condition changings in IM during operation. We use tube-based robust model predictive control (TMPC) as the current controller for IM to tackle the parameter mismatch problem. In TMPC the nominal constraints are tightened by the robust positively invariant set. The control laws of the optimization problem described by the TMPC are computed off-line by solving the multi-parameter quadratic programming, which significantly reduces the online execution time of the controller. Simulation results indicate that TMPC is more robust than PI and explicit model predictive control (EMPC). TMPC has lower searching burden than EMPC, which further improves the dynamics of the controller. Real-time feasibility of TMPC up to 8kHz sampling rate is demonstrated by experiments.