Optimal direct torque control of three-phase symmetric induction motors

Direct torque control (DTC) is a state of the art control methodology for induction motor drives which features very favorable control performance and implementation properties. However, one of its main deficiencies is the lack of a systematic design procedure for the inverter switching table, which is the core of the control system. This is addressed in this paper, where we propose a novel modelling and control approach for the DTC problem which is based on a systematic design procedure. The DTC drive comprising of a three-level dc-link inverter driving a three-phase induction motor is modelled in the hybrid mixed logical dynamical (MLD) framework, and a constrained optimal control problem is set up and solved over a receding finite horizon using model predictive control (MPC). Simulation results are provided and compared to the current industrial state of the art, which demonstrate the potential for performance improvements.