Nonlinear decouple controller design for wind power generator under ride-through

Doubly-fed induction generator (DFIG) based wind turbines has been used widely in variable speed and constant frequency wind energy generation system, but they are highly susceptible to any disturbances, such as faults, grid voltage sag or swell. In this paper, nonlinear control theory is used to handle couple between electrical and mechanical models in order to obtain nonlinear optimal control law and further implement three pairs decouple control structure. The technical works include: a new fourth-order control model of DFIG is derived; a novel nonlinear optimal control strategy based on input-output state feedback linearization theory for wind turbines with DFIG is presented; the simulation study and the test of low power hardware prototype of the proposed control scheme are carried out and partial results are presented. Results show the validity and efficiency of the proposed control strategy to improve the ride-through capability.