A PV Grid-Connected Inverter with Optimized AFD and MPPT Performance

Anti-islanding protection and maximum power point tracking for a two stage photovoltaic grid-connected inverter is designed in this paper. A new algorithm based on the traditional active frequency drift method is proposed to decrease none detection zone of the islanding detection. Perturbation and Observation method is adopted for the maximum power point tracking of the boost converter of the input stage. The stored energy in the filter capacitor changes under the voltage perturbation and it decreases the precision of MPPT. With stored energy change feed forward control, the precision of the MPPT method is improved.