Abstract: Intermittent, randomness and volatility of photovoltaic （PV） power generation, has been one of the main reasons restricting its large-scale development. This paper uses pure green hydrogen energy storage devices with high energy density to improve the reliability of power supply of PV array. In hybrid systems, hydrogen energy storage devices comprise electrolyzer, hydrogen storage tank and a proton exchange membrane fuel cell （PEMFC）, etc., for each cell by bringing together the power converters to the DC bus, and finally are connected via an inverter from the AC grid. Taking into account the constraints on the limit of pressure hydrogen storage tank, the electrolyzer and the rated output of fuel cell, this paper introduces high power density supercapacitors as a backup to ensure continuous and reliable power supply and the maximum use of solar energy resources. Under the premise of satisfying the constraint conditions of each component and hydrogen energy storage device starting a higher priority than supercapacitor, this paper proposes power coordination control strategy under six kinds of operation modes, whose effectiveness is verified by simulation analysis.

Key words: grid-connected photovoltaic, electrolyzer, fuel cell, supercapacitor