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

This paper presents a single stage solar photovoltaic (SPV) grid integrated power generating system using a three-phase seven level asymmetric cascaded H-bridge voltage source converter (VSC) operating at low switching frequency using level shift PWM (Pulse Width Modulation) technique. The use of asymmetric cascaded H-bridge topology presents the benefit of high number of voltage levels with less number of switching devices in comparison to symmetric cascaded H-bridge topology and offers the advantage of low switching losses, reduced total harmonic distortion (THD), ease of operation at high voltages and high power which results in enhancement of power quality in the proposed system. Simulated results in MATLAB validate the design and control algorithm under steady state and dynamic conditions at varying solar insolations.