State-space averaging model of wind turbine with PMSG and its virtual inertia control

With the increasing number of variable speed wind turbine generators connect to electrical grid, it is necessary for wind turbines to provide inertia support when the grid frequency drops. Because of its unclear physical concept and time-consuming calculation when the detail simulation model is adopted to deal with the virtual inertia control of the directly-driven wind turbine with permanent-magnet synchronous generator (D-PMSG), it is difficult to design the control scheme and analyze the frequency dynamic response of power systems according to the simulation results. Aiming at the physical essence of wind turbine virtual inertia control, this paper presents a properly-simplified state-space averaging model of the wind power integrated system (WPIS). The model can reflect the dynamic process of virtual inertia control. Based on the model, a linearized model is derived from equation transformation so as to get information about small signal stability. The state-space averaging model established in this paper can provide the technical means for designing the control scheme of virtual inertia control and analyzing the frequency dynamic response of the WPIS. The results of simulation tests have verified the effectiveness of the state-space averaging model.