Multi-phase multi-level AC motor drive based on four three-phase two-level inverters

A novel multi-phase multi-level ac motor drive is analyzed in this paper. The proposed scheme is based on four conventional 2-level three-phase voltage source inverters (VSIs) supplying the open-end windings of a dual three-phase motor (asymmetric six-phase machine), quadrupling the power capability of a single VSI with given voltage and current ratings. The proposed control algorithm is able to generate multi-level voltage waveforms, equivalent to the ones of a 3-level inverter, and to share the total motor power among the four dc sources within each switching period. The proposed ac motor drive has been numerically implemented and a complete set of simulation results is given to prove the effectiveness of the whole scheme.