Grid integration of single source SPV system using asymmetric cascaded 7-level VSC

Abstract

This paper presents a single stage solar photovoltaic (SPV) grid integrated power generating system using a seven level asymmetric cascaded H-bridge voltage source converter (VSC) operating at low switching frequency using level shift PWM (Pulse Width Modulation) technique. A novel technique using one SPV array to power the entire cascaded H bridges is introduced which drastically reduces the requirement of SPV array. The advantage of using an asymmetric cascaded topology is that high number of voltage levels are produced with less number of switching devices and provides ease of operation at high voltages and high power which results in enhancement of power quality in the proposed system. Simulated results validate the design and control algorithm under steady state and dynamic conditions at varying solar insolations.