Evaluating a Virtual Inertia Control Scheme for a DFIG Wind Turbine

Abstract

The power system inertia is considered as one of the fundamental parameters for the dynamic response to disturbances: the inertia of rotating machines determines the immediate response of frequency in power unbalance events. The connection of renewable generation units implies the use of power electronics creating an interface between the grid and the mechanical system, unlike conventional generation, the grid electrical frequency depends directly on the rotor frequency. In wind power generation, the power electronic converter decouples the mechanical speed from the grid's electrical frequency. In this paper, an evaluation of a virtual inertia control scheme for a variable wind speed turbine that simulates the inertia of a conventional generator supporting frequency extracting the inertia of the rotating turbine to improve the early transient response of the synchronous generators is presented. The speed deviation of a synchronous generator is used as a reference signal to feed the torque control on the wind turbine to level the output power as the synchronous generator finds a steady state speed after a disturbance.