Cooperative Frequency Regulation Strategy for Energy Storage with Different Control Methods Considering SOC and Active Power Margins

Conventional energy storage converters use phaselocked loop based grid-following control, which is regulated by an upper-level system. The converter of the grid-forming energy storage uses the grid-forming control. The grid-forming storage simulates the characteristics of a synchronous generator, which can generate voltage and phase spontaneously, and it also has inertia and damping characteristics. Firstly, the control principles of the following and structured network types are analyzed. Secondly, the dynamic frequency response characteristics of the power system after being perturbed are investigated, based on which a cooperative frequency regulation control method including grid-forming and grid-following energy storage is proposed. Finally, the experimental verification of the effectiveness of the control method is completed by simulation.