A single dc source cascaded seven level inverter with lcl filter integrating switched capacitor techniques

Abstract

Compared to existing CH-MLI system proposed CH-MLI system is replace all DC sources to capacitors except only one H- Bridge (it is with real DC source) and adds two switches for capacitor charging and discharging purpose. So capacitor charging is independent of Load. Beside the topology of the power electronic interface, the output filter also affects the quality of the load voltage .proposed a 7-level inverter is presented for grid integration systems along with its output LCL filter design. Analytical calculation of losses for the 7-level inverter and the output LCL filter is presented. It is also compared to the H-bridge inverter in terms of output voltage and current harmonics, and the overall losses. Capacitor voltage for desired level can be controlled using carrier phase shifted sinusoidal pulse width modulation (CPS- PWM) strategy instead of complex voltage control algorithms.