672 / 2019-04-18 10:43:27

Primary Frequency Modulation Control Strategy of Solar Photovoltaic-Energy Storage Hybrid System Based on Virtual Synchronous Generator

photovoltaic power generation system; energy storage system; virtual synchronous generator; primary frequency modulation; control strategy;

Photovoltaic module, connected to the grid through the inverter, is non-rotating stationary element and doesn’t have the rotational inertia of the synchronous generator. When connected to the power grid in a dense manner, distributed PV will reduce the system inertia, worsening the power grid's ability to cope with active power shortage. Under the same boundary conditions, the system frequency may drop even lower. Aiming at this problem, this paper puts forward the energy storage device in dc side to compensate system FM requirements. By adopting the control strategy of virtual synchronous generator for the inverter, the solar photovoltaic-energy storage hybrid system has characteristics similar to synchronous generator on the ac side, ensuring the stability of external output power of photovoltaic modules, and also enabling the distributed photovoltaic power station to have primary frequency modulation capability. Finally, this paper verifies the effectiveness of the proposed control strategy in MATLAB/Simulink simulation.