Direct Torque Control for Induction Motor Drives: A Model Predictive Control Approach Based on Feasibility

In this paper, we present a new approach to the Direct Torque Control (DTC) problem of three-phase induction motor drives. This approach is based on Model Predictive Control (MPC) exploiting the specific structure of the DTC problem and using a systematic design procedure. Specifically, by observing that the DTC objectives, which require the controlled variables to remain within certain bounds, are related to feasibility rather than optimality, and by using a blocking control inputs regime for the whole prediction horizon we derive a low complexity controller. The derived controller is an explicit state-feedback control law that can be implemented as a look-up table. Even though the controller is derived here for a DTC drive featuring a two-level inverter, the control scheme can be extended to also tackle three-level inverters. Simulation results demonstrate that the proposed controller leads to performance improvements despite its simple structure.