A self-starting switch mode power supply for multilevel inverters

Multilevel inverters are often employed in remote areas, where they are only exposed to a high dc voltage, e.g. a flying capacitor multilevel inverter for DC reticulation. The need for isolated dc power supplies presents a major problem, since no ac voltage is allowed in close proximity of the inverters. This paper aims at investigating the design and the development of a self-starting SMPS for multilevel inverters in the quest for solving the dc power supply problem. A self-starting circuit is presented and its bootstrapped based principle of operation is discussed. A circuit for pre-charging the flying capacitors of the multilevel inverter prior to switching of the inverter is also presented.