Grid-Connection Technique for a Photovoltaic System with Power Factor Correction

A new combined grid-connection/power factor correction technique for a single-phase two-wire (1Phi2w) photovoltaic (PV) system is proposed in this paper. The maximum power tracking DC/DC converter is also served as a charger to maintain the stored energy of the battery set. The grid-connected bidirectional inverter is applied as a generator/discharger at day time, supplying power to the load. The inverter also can be used as a charger, to maintain the minimum required voltage level of the battery set when the PV power is insufficient. Moreover, a parallel power factor correction (PPFC) function can be fulfilled via the presented control scheme of the inverter. The presented PV system features simplified hardware and lower cost, yet providing as many functions as possible. A power management algorithm is implemented in a DSP controller to manipulate the power relations among the PV system, the battery set and the utility. Experiments on a 1-kW PV system show satisfactory results of the power management and the nearly unity power factor (PF) at the utility side