Improved Demagnetization Control of a Doubly-Fed Induction Generator under Balanced Grid Fault

Doubly-fed induction generators are one of the most popular machines for variable-speed wind turbine. However, they are very sensitive to grid fault since the stator is directly connected to the grid. This paper analyzes the low-voltage ride-through performance of a doubly-fed induction generator-based wind turbine under balanced grid fault. An improved demagnetization control, immune to system parameter variation, is proposed to shorten the dynamic process. The investigation shows that the proposed method increases the probability of a successful ride-through at the recovery moment of balanced grid fault. Feasibility region for a representatively sized system is also investigated for balanced grid fault. In order to verify the proposed control method, laboratory experiments are carried out and the results demonstrate the analysis.