Structure of boost DC-link cascaded multilevel inverter for uninterrupted power supply applications

In this study, a structure of single-phase seven-level boost DC-link cascaded multilevel inverter (BDCLCMLI) is proposed. It consists of boost converter, DC-link module and H-bridge inverter. Compared with conventional CMLI and two level H-bridge inverter configurations, the proposed system results in reduction of voltage stress across the inverter switches, reduced power switches, DC source count and gate drive requirements. DC-link switching is achieved by multicarrier sinusoidal pulse-width modulation technique which results in improved quality of obtained output AC power. Reduction in DC source and switch count makes the system more cost effective. A simulation and prototype model of seven-level BDCLCMLI system is developed and its performance is analysed for various operating conditions.