Control Strategy for a New DC-to-AC Converter Consisting of a Multilevel Converter and a Linear Circuit

This paper discusses a new control strategy for a new DC-to-AC converter consisting of a multilevel converter and a linear circuit without any output filter inductor or capacitor. The multilevel converter is composed of series-connected H-bridge circuits, which can supply a multilevel voltage with reduced voltage ripples. On the other hand, the linear circuit is anti-series MOSFETs operated in a linear mode to eliminate the voltage ripples from the output terminal voltage of the DC-to-AC converter. New control methods are described to regulate the DC-capacitor voltage of each H-bridge circuit for the multilevel converter and to adjust the output current for the linear circuit. Experimental results are shown by using a 100-V 1.6-kW prototype DC-to-AC Converter to verify the validity of the proposed control strategy.