A three-level five-phase inverter with coupled inductors and DC flux cancellation

A three-level five phase inverter using coupled inductors is proposed in this paper. By inserting the coupled inductors into a half-bridge circuit, this topology is able to produce three output voltage levels. The usage of the inductors eliminates the need for dead-time zone which improves the total harmonic distortion of the output voltage. In case of the saturation in the magnet core caused by dc magnetic flux, two different cores are employed in the topology, that is, one toroidal core and one three-limb core. A proper connection of the windings is determined so as to balance the ac flux in the cores. A discontinuous switching strategy is designed for the proposed inverter. This strategy is based on the vector space decomposition so that the harmonics generated in the x-y sub-plane are restricted. To reset the ac flux in the coupled inductor, the sub-redundant switching states are utilized within the carriers. Simulations are executed in the MATLAB to validate the topology and the proposed switching strategy.