A new Modified H bridge seven level seven switch with reduced number of switches for medium voltage applications

Multilevel inverters have great applications in medium-voltage and high-power applications and also have found successful industrial applications. Modified full bridge inverter is one of the most popular topologies among the multilevel inverters because of lower number of switches and simpler structure than others. In this paper, a seven-switch and seven-level modified full bridge topology is proposed. Compared to the practical seven-level inverters like neutral point inverters, the proposed inverter reduces three active switches and has lower conduction loss and simple control. The input voltage to the given inverter is a DC source (Vdc) which has been shared between three identical capacitors and it is capable of producing output of seven level (Vdc, 2Vdc/3, Vdc/3, 0, -Vdc, -Vdc/3, -2Vdc/3). As more steps are added to waveform, the harmonic distortion of the output waveform decreases. The proposed modulation enables the proposed inverter to operate under both active and reactive power conditions. A 1KVA single-phase sample circuit is simulated by the PSPICE software to verify the validity of the proposed topology and modulation method. The results show the proposed topology is suitable for photovoltaic (PV) applications.