Technology Status Analysis of Key Power Electronic Devices for Photovoltaic DC-Connected Power Systems

Compared with the photovoltaic AC-connected power system, the photovoltaic DC-connected system has advantages of higher efficiency, less converters’ classes, smaller transmission loss, and larger transmission capacity. However, technologies and engineering applications of the photovoltaic DC-connected power system are not as mature as the AC system. Topologies of high boost ratio DC/DC converters, capacity and working frequency of high-frequency transformers, and voltage, current and turn-off time of DC circuit breakers are analyzed in this paper to illustrate the engineering application feasibility of photovoltaic DC-connected power systems.