A Double-Voltage Vector Based Model Predictive Control Method for Three Phase Four-Switch Fault-Tolerant Converter

Bidirectional AC/DC converter can be reconstructed as a three-phase four-switch (TPFS) fault-tolerant converter when leg fault occurs to enhance its fault tolerant operation capability. In this paper, to further improve the control performance of the TPFS fault-tolerant converter, a new model predictive control (MPC) method is proposed. Considering that there are only four voltage vectors for the TPFS fault-tolerant converter, to reduce the current ripples, double voltage vectors are selected and applied per control period in the proposed method. To reduce the calculation burden, the duration time of each voltage vector is calculated based on the principle of the modulated MPC. Furthermore, the effectiveness of the proposed double-voltage vector based MPC strategy is analyzed in theory in detail for the first time and then it is further verified by comparative simulation studies.