A new bidirectional hybrid multilevel inverter with 49-level output voltage using a single dc voltage source and reduced number of on components

This paper proposes an isolated bidirectional asymmetrical multilevel inverter topology composed by an H-bridge (HB) inverter connected to the primary side of transformer. The transformer secondary side is composed by two windings, and each one is connected to a new cell introduced in this work. The proposed new cell is based on the conventional HB inverter, where two bidirectional switches are added to each HB leg, thus resulting in the structure referred to as CHB-2bs. The transformer can also be composed by multiple secondary winding in order to provide the necessary voltages to supply as many as CHB-2bs cells are. A 600 W laboratory prototype with dc input voltage of 48 V and an ac output voltage of 220 V, 60 Hz using a grain-oriented silicon-steel toroidal transformer operating at 300 Hz is implemented to validate the theoretical assumptions and the advantages addressed to the CHB-2bs cell.