Linear Control Gain for Synthetic Inertia of a PMSG-Based Wind Turbine Generator

This paper proposes a synthetic inertia control (SIC) scheme for a permanent-magnet synchronous generator-based wind turbine generator (WTG). The proposed SIC scheme uses only the frequency deviation loop operating in conjunction with the maximum power point tracking loop. To improve the frequency nadir while preventing over-deceleration of a WTG, the proposed scheme employs a variable control gain for the frequency deviation loop, which varies linearly with the rotor speed. In the high-rotor-speed region, the gain is set to be high so that the frequency nadir can be improved. In the low-rotor-speed region, the gain decreases with the rotor speed so that over-deceleration can be prevented while improving the frequency nadir. To investigate the efficacy of the proposed gain, simulation case studies are conducted in the modified IEEE 14-bus system under varying wind speeds and event sizes. Simulation results indicate that the proposed scheme successfully improves the frequency nadir while preventing over-deceleration of the rotor speed by varying the control gain in a linear manner with the rotor speed.