Current Control of Grid-Connected Simplified Split-Source Converters (S3I) for Single Phase Photovoltaic Microinverter Application

This paper presents design of grid-connected single phase simplified split source inverter and effective grid current control strategy for photovoltaic (PV) microinverter application. The operation of principle of the split-source inverter is discussed and how the proposed current control method is applied to the related system is explained in detail. The simulation is carried out by using Powersim (PSIM) software environment to demonstrate the operating of the proposed system. The proposed microinverter system includes the PV module and simplified split source inverter. The grid current is adjusted to a value that corresponds to maximum power operating point of the PV module and this power is transferred to grid in a microinverter system. The maximum power of PV module is obtained using perturb and observe (P&O) method and unipolar sinusoidal pulse width modulation (SPWM) is used for simplified split source power converter. Various simulation tests have been performed on the proposed micro inverter system at various and constant irradiation values. The simulation results show that grid current control strategy is implemented on simplified split source inverter for the single-stage PV -grid-connected power generation competently, producing constant DC-link voltage. Reduction of number of switches, high voltage boosting gain and no need for additional DC-DC converters are features of high efficiency simplified split source inverter.