High efficiency power conditioner for photovoltaic power generation system

In this paper, the techniques for a gradationally controlled voltage inverter (GCVI), which is a high efficiency inverter, and a high efficiency power conditioner utilizing the GCVI technique for photovoltaic power generation systems are described. A GCVI consists of several inverters operated at different voltages in series and outputs voltage with a sine waveform by combining these outputs. The features of GCVI are low power loss, low electromagnetic noise, small output filters and generating an AC voltage higher than the DC voltage input into the GCVI. The last feature helps the DC/DC converter of the power conditioner to operate at high efficiency. The GCVI type power conditioner (PV-PN40G) achieves high efficiency, which is 97.5% at the maximum power point, a sealed structure, and quietness, 30 dB noise.