A New Hybrid Multilevel Inverter with Extended Number of Voltage Steps

This paper presents and studies an improved multilevel inverter topology to produce higher voltage levels with reduced switching devices at the inverter output. The suggested topology is based on SCSS multilevel inverter. In this topology, DC sources are divided into two groups, inner group and outer group. The function of the outer dc source group is to create the square waveforms that are close in nature to the required output waveforms. However, the inner group is used to increase the number of the DC voltage levels to produce an output voltage close to the desired wave. This task is accomplished by arithmetic operation (addition or subtraction) of the value of the inner DC source with the blocks created by the outer group, respectively. A hybrid modulation scheme has been utilized to substantially reduce harmonics distortion. The performance of the proposed topology is then compared with other conventional and concurrent structures of multilevel inverter as well as evaluated by simulation results.