Predictive flux and torque control of induction motor drive under post-fault operation of three-phase voltage inverter

In this paper a direct finite-state predictive flux and torque control of an induction motor drive system fed by four-switch three-phase voltage inverter was discussed. This specific inverter topology can be used after faulty inverter leg isolation from an electric motor under single IGBTs open-circuit faults. To overcome a significant problem related to the four-switch inverter topology, namely capacitor voltage unbalance in DC-link, a solution based on the voltages measurement was developed. In the proposed approach, depending on a motor drive operation point, in order to achieve a high drive performance a weighting factor of a cost function term related to capacitor voltages balance is adapted. To confirm the proposed method, simulation results were presented under a wide range working conditions of an induction motor drive system.