Photovoltaic power interface circuit incorporated with a buck-boost converter and a full-bridge inverter

This paper presents an efficient photovoltaic power interface circuit incorporated with a buck-boost converter and a full-bridge inverter. It connects up a solar array to power a utility line. The proposed interface circuit consists of five switches, an input inductor, and LC filters. The buck-boost converter operates at high switching frequency to make the output current a sine wave, whereas the full-bridge inverter operates at low switching frequency of 50-60 Hz, which is determined by the ac utility line frequency; thus, it can reduce the switching losses incurred by the full-bride inverter. In the output stage, a high power-factor is achieved without an additional current controller owing to the input inductor current operatly in a discontinuous conduction mode. Consequently, it has a simple and robust circuit configuration. Operational modes are analysed, and then the validity of the proposed interface circuit is verified through computer-aided simulations and experiments based on a laboratory prototype of 150 W.