A study on the frequency response of a small scale DFIG-based VAWT considering the moment of inertia: A control perspective

Maximum power extraction by wind turbines requires the control strategies to have precise tracking and the turbines to adapt to increasing wind speed changes as fast as possible. A wind turbine should also be able to provide frequency support to the grid while maintaining stability. This study focuses on the way inertia affects the performance of the vertical axis wind turbine (VAWT) and its ability to provide frequency support. A doubly fed induction generator (DFIG) coupled to a small-scale H-type VAWT is used for the study. We apply gain scheduling control for torque control of the doubly fed induction generator for four different inertia values. It is observed that low inertia is desirable for the turbine. An increase in inertia leads to an increase in the time required to reach steady state velocities which could lead to halting of the turbine. This results will be of good help for turbine designers in deciding the best design parameters for optimal power extraction.