Virtual Inertia Control and Short-Term Primary Control for PMSG-Based Wind Turbine Using Supercapcitor

In order to improve the inertial response and frequency regulation capability of the power system with high proportion wind power generation, a new virtual inertia control and short-time primary control for the permanent magnet synchronous generator (PMSG)-based wind turbine (WT) are presented in this paper. The proposed control scheme can enable individual PMSG-based WT to provide an effective inertial response and short-term primary frequency regulation support, which helps to slow down the rate of change of frequency (ROCOF) and reduce the maximum deviation of frequency under frequency disturbance. In order to achieve the proposed scheme, the supercapacitor needs to be directly connected to the back-to-back converter of the WT to increase the additional energy storage required for frequency support. The DC voltage is varied with the grid-side converter following the derived equation of the proposed control scheme to exchange power with connected grid. In addition, the supercapacitor size for proposed frequency control is discussed. Finally, the proposed control strategy is verified in PSCAD/EMTDC, and the simulation results show that the proposed control strategy can improve the inertial response and frequency stability of the system.