Integrated Control Strategy of Variable Coefficient Virtual Inertia for Doubly-Fed Wind Turbines with Primary Frequency Regulation

Wind power generation has emerged as one of the most scalable renewable energy sources. However, the decoupling of wind turbine speed from grid frequency in doubly-fed induction generators (DFIGs) while tracking maximum power leads to a lack of frequency regulation capability in wind power systems. To address this issue, a comprehensive control strategy is proposed, integrating the variable virtual inertia control of DFIGs with primary frequency control, enabling the wind turbines to achieve comprehensive control over system frequency and smooth out frequency fluctuations. This control mechanism employs a dynamic factor based on frequency deviation, allowing for a rapid increase in electromagnetic power during significant frequency drops, effectively supporting grid frequency. Through an in-depth analysis of the primary frequency control capabilities of wind turbines, the pitch angle control has been improved, resulting in a control strategy that allows for flexible adjustment of the static regulation coefficient of wind turbines. Simulation results validate the feasibility of the proposed frequency control strategy.