Model Predictive Direct Torque Control for MV drives with LC filters

This document describes the implementation of the model predictive direct torque control (MPDTC) algorithm for the control of three-phase induction motor drives comprising a three-level dc-link inverter with an output LC filter. As the filter introduces delays in the system, the motor torque and flux are no longer directly controllable. Therefore the inverter torque and flux are introduced and the MPDTC scheme is redesigned to keep them and the inverter´s neutral point potential within given hysteresis bounds also according to today´s state-of-the-art solution with DTC. Moreover the MPDTC control objective is altered to target directly the reduction of the inverter switching losses rather than the switching frequency, resulting in a significant reduction of the switching losses with respect to standard DTC. Simulation results are provided, analyzing the benefits of MPDTC in terms of inverter switching losses reduction (which for 90% speed and full load amount to 22%) as opposed to a measure of the motor´s losses, namely the motor´s current and torque THD.