| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 399600 | International Journal of Electrical Power & Energy Systems | 2013 | 8 Pages |
The influence of grid voltage dip on doubly fed induction generators (DFIGs), especially rotor current, has received much attention. So, in this paper, the rotor short-circuit current of based-DFIG wind turbines is considered in a generic way, which is suitable to analyze the cases under different levels of both voltage sag and voltage rise. A direct method is proposed to obtain accurate expression of rotor current. Firstly, the rotor open-circuit voltage in terms of stator flux is determined, and the dynamic equation of the rotor current reduces to a first-order differential equation under rotor short-circuit operation condition. Secondly, the expressions of the rotor open-circuit voltage before and after a fault are obtained, respectively. Finally, based on the obtained expression of rotor voltage, the rotor short circuit currents before and after a fault are obtained by solving the first-order differential equation. This analysis contributes to understand the causes of the problem, and as a result, it helps to adapt reasonable approaches to improve the capacity of the uninterrupted operation of wind power generation during a voltage fault. Simulation results evaluate the proposed analysis.
► We theoretically analyze the rotor fault current of based-DFIG wind turbines using a direct method during voltage fault. ► Accurate expression of rotor fault current is obtained using the proposed method during voltage fault. ► The rotor fault current expression is considered in a generic way, which is suitable to analyze the cases under different levels of both voltage sag and voltage rise. ► The proposed method is simple.
