Robust current control of doubly fed wind turbine generator under unbalanced grid voltage conditions

This paper presents the design of a H∞ current controller for doubly fed induction generators (DFIGs) in order to maintain stable operation under unbalanced voltage conditions. The H∞ current controller has a multi-input and multi-output (MIMO) structure and is designed using the loop shaping method. Case studies have been carried out in order to verify the efficacy of the proposed H∞ current controller for DFIGs. The case study results show that the proposed H ∞ current controller can realize different control objectives, i.e. stable stator current, stable stator active power and stable stator reactive power. It is also shown that the H ∞ current controller is less sensitive to the parameter perturbation.