Adaptive Inertia Based on Secondary Control Strategy for VSGs with the SOC Constraint of DC-Side Energy Storage

The virtual synchronous generator (VSG) can provide inertia to the system, and effectively support the system frequency. However, the VSG inertia setting is subject to the physical limitations of the DC side, which cannot be changed arbitrarily. Aimed at this deficiency, this paper proposes a VSG inertia adaptive control strategy based on hybrid energy storage system (HESS). Based on the traditional inertia adaptive control, this strategy second adjusts the virtual inertia according to the state of charge (SOC) of the supercapacitor (SC), which can not only prevent the SC from overcharge and overdischarge, but also improve the frequency characteristics of VSG in the transient process. Finally, the feasibility and effectiveness of the proposed strategy are verified by comparing the control effects of different VSG strategies through Matlab/Simulink simulation.