Medium-Voltage Cascaded Sequential Topology for Large-Scale PV Plants

Photovoltaic (PV) conversion systems are in continuous development due to their increasingly competitive prices. The traditional configuration of large-scale PV plants is based on high-power central inverters, which have reduced cost by increasing power rating. However, this reduction expected saturate the near future, mainly an increase dc wiring. Cascaded appeared as potential solutions continue reducing plant cost. They consist several units whose ac outputs connected series. This enables power-rating each individual unit, while maintaining rating structure. Thus, placed closer panels, wiring In paper, a novel three-phase topology for medium-voltage cascaded presented. proposed formed units, one with number stages, namely, dc/ac, medium-frequency isolation and ac/ac. Moreover, thanks its sequential operation modulation technique, zero-voltage switching zero-current achieved all stages. way, respect has advantages systems. comparison previously investigated topologies, also presents promising characteristics, representing efficiency increase. An experimental validation carried out laboratory prototype consisting three units.