Cascaded H-bridge multilevel inverter for increasing output voltage levels

This paper presents a cascaded H-bridge multilevel inverter (CHMI) and proper switching method for increasing output voltage levels. In recent year, CHMI have presented an attractive topology for high power and medium-voltage applications for increasing voltage levels. In proposed scheme, each output terminals of H-bridge modules are connected with transformer and the secondary side of each transformer is connected in series to synthesize output voltages. It is possible to increase output voltage level by selecting proper turn ratio of transformer. In addition, it can be simply realized through the multi-carrier based PWM method considering balanced power distribution each H-bridge cells. The validity of proposed scheme is verified by simulation results.