A Nine Level Asymmetrical Multilevel Topology for Grid Connected PVGS

This paper introduces a nine-level modified packed U-cell topology (MPUC). The proposed inverter requires two different DC voltage sources. PV arrays are used as these sources. In this paper, a comparison between MPUC topology and proposed topology on the basis of output voltage total harmonic distortion (THD) is explained. Perturb and Observe (P & O) technique is used to track maximum power point to increase the efficiency. A DC-DC boost converter is used to maintain output voltage of PV panel at desired level. The output of inverter is further filtered using LC filter. MATLAB/SIMULINK environment is used to simulate grid-connected Photo Voltaic Generation System (PVGS) with proposed multilevel inverter. The THD of output voltage of proposed inverter is 0.71% with filter for standalone application and 0.22% with filter for grid-connected application, both lies within the limit according to IEEE-519 standards.