A Current-sensor-less MPPT Algorithm for Single-stage Grid-connected PV Inverters

A current-sensor-less maximum power point tracking(MPPT) algorithm for single-stage grid-connected photovoltaic inverters was proposed.The MPPT algorithm is based on energy coupling among the PV module,the filtering capacitor and the power convertor.The PV module output power change is reflected by capacitor voltage by keeping the grid-feeding energy equal under two consecutive periods.The relationship between output power of PV module and voltage of the decoupling capacitor was given in detailed to analyze and categorize different operation modes of the PV module,resulting in improved disturbance rules compared to the conventional perturb and observation method.Steady state experiments were carried out on a 200W prototype.