A NOVEL CONTROL TECHNIQUE FOR SINGLE-PHASE FIVE LEVEL INVERTER FOR A GRID-CONNECTED PHOTOVOLTAIC SYSTEM

A peak current control technique (PCCT) for the generation of the switching sequence, for a single phase single stage five level inverter is proposed in this paper. This inverter meant for a solar PV system, fundamentally incorporates a switching capacitor (SC) unit and a virtual DC-bus so that boosting capability is achieved in a single stage. By employing a common grounding method, an extra benefit of minimizing the leakage current is obtained. A filtering technique, based on a Modified Second Order Filter (MSOF) is utilized for eliminating the harmonics in the injected current which enhances the power quality at the Point of Common Coupling (PCC). A variable step, perturb & observe based Maximum Power Point Tracking (MPPT) is employed for optimum extraction of power from the PV array. A detailed investigation of the inverter system incorporating the proposed control technique has been carried out, under various working conditions, using MATLAB/Simulink simulation studies.