Four-level five-phase open-end winding drive with unequal DC-link voltages

A four-level five-phase open-end winding drive topology is introduced in the paper. The system comprises a five-phase induction machine with an open-end stator winding, supplied using two two-level voltage source inverters with isolated and unequal dc-link voltages, in the ratio 2:1. The topology offers the advantages of a modular structure with fewer semiconductor components and has a greater potential for fault tolerance, compared to an equivalent single-sided four-level drive. Due to the large number of switching states, development of a suitable modulation method can be challenging. In this paper two carrier-based PWM strategies are developed and the performance is investigated using simulations.