A novel topology for power quality improvement of grid-connected photovoltaic system

Abstract

Photovoltaic and fuel-cell dc voltage, most of the time converts to ac voltage in a two-stage process. In the first stage, a dc-dc convertor boosts the dc voltage and then, the increased dc voltage turn into ac voltage using an inverter. This topology has two major problems. First and foremost, the overall reliability of system declines. More importantly, multiple problem of using large electrolyte capacitor, which reduces the overall lifetime of the system, leads us to eliminate them. Consequently, integrating boosting phase and inverting phase in one stage is suitable. Also there is another significant problem with PV-Modules. Some times of the day, required radiation intensity for the PV-Modules decrements results in a reduction of the output voltage of the converter which is not desired from the power quality point of view. In this paper a new topology is suggested in order for increasing the power quality of grid-connected PV-Modules. A current source boost inverter (CBSI) is utilized for this aim. Major advantage of this CBSI, is its low-loss switching pattern which results in its better efficiency.