Control of Doubly Fed Induction Generator under symmetrical voltage dips

Abstract

Doubly Fed Induction Generator (DFIG) is largely used in wind generators. It provides variable speed characteristics in a cost-effective way. The main drawback of this machine is its sensitivity to grid disturbances. Voltage dips cause overvoltages to appear in the rotor that can surpass the converter limits. Additionally, variations of the grid voltage cause the stator flux to oscillate at the grid frequency. This paper proposes a novel control strategy to overcome these problems; furthermore, it reduces the rotor voltage, improving the control of the rotor current and it accelerates the dumping of the flux oscillations.