Multilevel Operation and Input Power Balancing for a Dual Two-Level Inverter with Insulated DC Sources

A multilevel inverter topology feeding a three-phase open-end winding machine is analyzed in this paper. The scheme is based on the use of two insulated DC supplies, each one feeding a standard two-level three-phase inverter. The three-phase six-wire winding is connected across the output terminals of the two inverters. A new modulation technique that is able to regulate the sharing of the output power between the two DC sources in each switching cycle is presented. The performance of the whole system has been verified by both numerical and experimental tests.