Virtual Synchronous Generator Based on Type-IV Wind Turbine with Supercapacitor as Storage

With the help of supercapacitor as energy storage, the type-IV wind turbine (WT) can be controlled as virtual synchronous generator (VSG). The virtual inertia provided by the grid-forming strategy can enable the grid frequency support function of WT, which is beneficial for the frequency stability of the power system confronting the increasing penetration of renewable energy. In this paper, a grid-forming WT solution based on supercapacitor connected to the DC-link via a DC/DC converter is proposed. The VSG controller which does not need frequency curtailed mode operation of WT is investigated. The virtual capacitor strategy of DC/DC converter is proposed to regulate the power flow of the supercapacitor. The supercapacitor capacity is also analyzed. The effectiveness of the proposed strategy is verified by the simulation.