Decentralised coordination control strategy of the PV generator, storage battery and hydrogen production unit in islanded AC microgrid

Abstract

The fluctuation and intermittence of the distributed renewable energy sources (RESs) limit the connection to the main grid and cause large-scale power curtailment. This issue can be addressed by the application of a hydrogen production unit (HPU), which is compatible with the disadvantages of RESs and can achieve large-capacity and long-term absorption of the electric energy. A decentralised coordination control strategy among the generation, storage and HPU are proposed in the photovoltaic (PV) dominated islanded AC microgrid. Firstly, the energy conversion efficiency from electric energy to hydrogen energy of HPU is derived, based on which the efficiency adaptive control is proposed to regulate its power consumption by adjusting the efficiency reference according to the bus frequency. Secondly, the state of charge and the instantaneous power of the storage are considered in the control strategy, which can avoid the storage being overused or damaged. Thirdly, the control strategy of the PV generator is designed to adaptively regulate its output power from maximum power point tracking mode to the reference power point mode seamlessly. Finally, the stability of the whole control strategy is analysed and the control effectiveness is verified based on the RTLAB experiment platform.