A Novel Scheme Suitable for High-Voltage and Large-Capacity Photovoltaic Power Stations

The efficiency, power quality, and reliability of renewable energy power conversion systems are key factors for future industrial applications. This paper presents a novel scheme to improve the performances of high-voltage large-capacity photovoltaic (PV) power stations. The power conversion of the PV system is divided into two stages, i.e., dc/dc power conversion and dc/ac power conversion. In the dc/dc stage, many power units are connected in parallel, each one of which includes a PV array and a nonisolated dc/dc converter. The dc/ac power conversion is equivalent to a voltage source in series with a current source. Square wave converters, together with transformers, are employed for the voltage source, which is based on the multipulse technology of square wave superposition. Pulsewidth-modulated converters are employed for the current source. Simulated waveforms with a whole 10-MVA/10-kV PV system are shown, and experimental results with a 100-kVA/1-kV dc/ac prototype are displayed.