Current controller design for DFIG‐based wind turbines using state feedback control

Abstract

Doubly-fed induction generators (DFIGs) are widely used in wind energy conversion systems. The dynamic features of DFIGs make it important to focus on designing high-performance control schemes. However, the dynamic characteristics of such generators depend on nonlinear parameters, such as stator flux, stator current, and rotor current, which increase overall system complexity. Therefore, robust controllers must be implemented with the ability to support the dynamic frequencies of wind energy to ensure system stability. Conventional vector control configurations that use proportional-integral controllers have various drawbacks, such as parameter tuning difficulties, mediocre dynamic performance, and reduced robustness. In this study, improving DFIG dynamics by applying a multivariable state feedback current controller with a feedforward component to improve the steady-state and transient characteristics of the controller has been introduced and discussed. Multivariable state feedback controllers are proposed to replace the proportional-integral controllers on both the rotor and grid sides. The proposed controller is designed using a multivariable system and feedforward control for input reference and incorporating disturbances into the control equations for fast transient responses. To demonstrate the advantages of this controller, experimental studies are presented for both the transient and steady states.