The LVRT control ability analysis of BDFIG motor side converter

There is no brush in the brushless doubly fed induction generator(BDFIG). Because of this excellent maintenance feature, it has well prospects in wind power system. The low voltage ride through (LVRT) is the most important grid code of wind power system. The control limit of the generator side converter is the key point to the LVRT control strategy. It has great research value. This paper proposes a method to find out the control limit of BDFIG MSC under voltage dips. First, the control limit calculation is formulated to be an optimization problem with practical constraints. Then, such optimization problem is solved with Pontryagin's minimum principle (PMP) and the control limit can be obtained. After compared with the DFIG system, the results shows that the BDFIG has more excellent LVRT capability.