Active Damping Control of Torque Oscillation in the Drive Train of Variable Speed Wind Turbine

Wind turbines are required to provide frequency support to the electrical grid. This is critical for sustaining grid stability. However, the supplementary frequency control may excite torsional oscillation in a wind turbine-driven train. Therefore, this paper proposes a combined inertia control and active damping control of torque oscillation in the drive train of a double-fed induction generator (DFIG) wind turbine. The active damping control is implemented using a PID controller, which is designed based on damping optimisation criteria. Moreover, inertia support for the grid based on the rotating mass of the DFIG wind turbine is provided. In order to test the effectiveness of the system, simulations with two wind turbines are used to investigate the combined inertia support and active damping control.