High Gain Multilevel Inverter Based Grid Integrated Solar Power Transfer System with Power Quality Enhancement

A high gain multilevel inverter (HGMLI) based solar power transfer system (SPTS) is proposed in this paper. The five-level symmetrical source topology consists of eight semiconductor switches and two non-isolated DC sources. The HGMLI is comprised of a multilevel generator unit and a polarity alternating unit. Four switches in the circuit operate to achieve unipolar multiple levels and another four switches change the alternate polarity to get the desired five-level AC output voltage. Four switches are operated in level-shifted pulse width modulation and the other four are at the fundamental frequency. Moreover, the polarity alternating switches are operated at zero voltage levels to reduce the switching losses. A voltage booster circuit extracts maximum power from the photovoltaic (PV) array and exhibits a high gain in the voltage transformation for obtaining the desired DC-link voltage even for a low input voltage. The MLI is controlled by a second-order generalized integral-based filter to integrate active power to the grid. At the point of common coupling (PCC), a nonlinear harmonic load is connected, and its impact on grid power quality is mitigated by the SPTS operation maintaining within IEEE limits. Hence, maximum power extraction, active power injection, and power quality enhancement are the major objectives of this work. The proposed system performance is validated at different operating conditions with extensive analysis in the MATLAB/Simulink model.