Optimal speed tracking for double fed wind generator via switching control

For the strong coupling and nonlinear nature of double fed wind generator, this paper focuses on the modeling and speed tracking switching optimal control of double-fed wind generator. firstly, a fifth order nonlinear model be established in the based stator flux oriented synchronous rotating coordinate system, which is closer to the actual object and presents more good dynamic performance. Secondly, since this model is a fifth order nonlinear model and the use of nonlinear control methods to solve it are complex, linearizing the nonlinear system around different operating points is presented so that matural linear control methods can be used. Then, a multimodel Linear Quadratic (LQ) switching controller is designed based on the combination of switch control and optimal control by the corresponding system parameters of double fed generator at different operating points. The ideal of the control is by controlling the voltage of the generator rotor to adjust the generator angular velocity to track the optimal angular velocity. Finally, a 11kW wind generator is considered to illustrate the good performances brought by the proposed approach by presenting and discussing the simulation results, and so it´s verified that the designed switching system can meet the need of actual project well.