Variable Switching Point Predictive Torque Control for the Four-Switch Three-Phase Inverter

This paper presents a model predictive control (MPC) strategy for the four-switch three-phase inverter (FSTPI) driving an induction machine (IM). A state-space model of the plant, that takes into account the capacitor voltage imbalance, is introduced. The objectives of the proposed MPC-based approach are to control the machine torque and stator flux and to minimize capacitor voltage fluctuations. Furthermore, in order to reduce the high torque and flux ripples, a variable switching time point approach is implemented. The algorithm and mathematical calculations for the determination of the switching time point are presented. Simulation data verify the performance of the presented control strategy.