Generalised single-phase N-level voltage-source inverter with coupled inductors

A generalised single-phase N-level voltage-source inverter is presented in this study. The number of output voltage levels is increased by using split-wound coupled inductors instead of several DC voltage sources and split and/or clamp capacitors of the conventional multilevel converters. As an example, the operation of the nine-level inverter is analysed and a proper switching strategy is proposed. With this modulation strategy, no DC components exist in the inductor voltages and currents, which is very helpful for minimisation of the inductors. Voltage steps are only one-quarter of the DC voltage source, leading to much reduced dv/dt. Moreover, this inverter compared with other inverters with the same number of voltage levels requires fewer switches and passive components. This study uses simulation and experimental results to illustrate the operation of the proposed inverter.