Control of single phase grid connected transformerless PV inverter system

This paper presents the simulation performance of control of a grid-connected photovoltaic maximum power point tracking system with highly efficient and reliable inverter concept transformerless inverter. Perturb and Observe technique based on variation of power and voltage is used to extract maximum power from photovoltaic power system. A dc-dc boost converter is applied with the technique by changing duty ratio of the PWM signal of the converter switch. A single-phase highly efficient and reliable inverter concept transformerless inverter provides a power flow into grid. The control of the inverter is based on the grid voltage and current and also dc-dc boost converter output voltage values. The system performance is evaluated in terms of PV module and dc-dc boost converter output voltages and currents, grid current and voltage, leakage current, active and reactive powers and power efficiency characteristics. The simulation results show 97.96% maximum efficiency, 96.84% European efficiency and 97.60% Californian efficiency with 20 kHz switching frequency for the HERIC inverter on the proposed system