Predictive current control of a six-phase asymmetrical drive system based on parallel-connected back-to-back converters

Parallel-connected three-phase back-to-back converters improve the fault tolerance and reduce the current rating of a six-phase asymmetrical drive system. This paper proposes a Model Predictive Control (MPC) strategy for an asymmetrical six-phase induction machine drive system that consists of two parallel connected three-phase back-to-back converters. A discrete-time mathematical model is derived that includes the parallel-connected rectifiers, inverters, and machine. Based on the derived model, an MPC strategy is developed to regulate the dc-link voltages, maintain unity power factor at the grid side, and control the current/torque of the machine. Performance of a six-phase machine operating under the MPC strategy is evaluated based on time domain simulation studies in the MATLAB /SIMULINK environment.