Doubly-fed Induction Generator Control for Wind Power Based on Passivity and Adaptively Reduced Order Observer

A nonlinear control scheme was proposed for doubly-fed wind power generation based on passivity and adaptively reduced order observer.The model of doubly-fed induction generator(DFIG) by Euler equation was established,and the system was decomposed into two feedback interconnected passive subsystems,an electrical subsystem and a mechanical subsystem.The electrical subsystem was the unique one to be considered in design process of the controller,thus,simplifying the control algorithm.The error equation of current was obtained through the nonlinear analysis.The torque and speed controller of DFIG was then designed,and the required reference rotor voltages were deduced.Based on the model reference adaptive approach,an adaptively reduced order observer was designed for the estimation of the motor speed,and speed identification law was proposed,the gain matrix of the observer was obtained by pole-placement technique.Simulation results show that the proposed passivity-based control and adaptively reduced order observer has a good dynamic and static performance;Passivity-based control can realize independent modulation of the stator active and reactive power;Meanwhile,passivity-based control simplifies control algorithm and has good robustness for the motor parameters and load disturbances compared with the traditional vector control.