New modelling of photovoltaic power integration system and its control strategy for medium-voltage DC distribution network

Here, a novel photovoltaic power integration system based on LLC resonant converters is proposed for medium-voltage DC distribution network, which exhibits a feasible and efficient solution for large-scale solar energy integrating into DC grids. A control system with the voltage signal generation part and the frequency control part is designed to realise the current and voltage sharing of the sub-module, while achieving the maximum power point tracking (MPPT) of the PV arrays. To verify the practicability of the system with many switching devices, this paper proposes an optimisation model to accelerate the simulation speed of this system without losing accuracy. Finally, the feasibility of the proposed system is validated by the simulation based on PSCAD/EMTDC.