A multilevel five-phase open-end winding drive with unequal DC-link voltages

A new multilevel five-phase open-end winding drive topology is proposed and analysed in this paper. The topology consists of an induction machine with open-end windings, supplied with one three-level and one two-level voltage source inverters (VSIs). The two inverters are fully isolated with dc-link voltages in a ratio 2:1, which results in performance equivalent to that of a four-level five-phase single-sided topology. In addition to four-level operation, two- and three-level operating modes are also possible, depending on the modulation algorithm. This feature can be used in order to reduce switching losses and improve harmonic performance. Two carrier-based pulse width modulation (CB PWM) strategies are evaluated using detailed numerical simulations.