A novel type of combined multilevel converter topologies

A novel type of combined multilevel converters is discussed, combining the conventional diode clamped or flying capacitor multilevel converters with two-level bridge legs. Compared with the conventional multilevel converters, this novel type requires much fewer clamping diodes and flying capacitors at the same number of output voltage levels. So the reliability of the circuit is improved and costs are reduced. The construction rule and modulation method of these topologies are presented in the paper. To confirm the validity of the new topologies, a combined diode clamped seven-level half-bridge inverter and a combined flying capacitor five-level half-bridge inverter are taken as examples for simulations and experiments, and the results proved the validity.