Control of a Two Stage High-Frequency Isolated PV-Grid Integrated System with Improved Power Quality

Solar energy remains the predominant choice for renewable energy in residential and commercial applications. It is notable that residential PV-grid integrated systems are experiencing significant growth in recent times. The non-isolated PV-grid integrated systems encounter safety and leakage current issues. A novel two stage solar PV-single phase grid integrated system with galvanic isolation is proposed in the paper. The system consists of an LLC resonant DC-DC converter (LRDC) in order to provide galvanic isolation along with boosting of PV voltage and MPPT control. The LRDC employs zero current switching (ZCS) to reduce the switching stress, thereby enhancing the converter lifespan. Additionally high-frequency galvanic isolation makes the system more compact. A single phase voltage source inverter with second order generalized integral (SOGI) based grid integration control incorporated with power quality (PQ) enhancement is connected to the DC link. The performance of the proposed system is evaluated using matlab simulink model under different operating conditions.