An adaptive Phase-Locked Loop algorithm for faster fault ride through performance of interconnected renewable energy sources

Interconnected renewable energy sources require fast and accurate fault ride through operation in order to support the power grid when faults occur. This paper proposes an adaptive Phase-Locked Loop (adaptive dαβPLL) algorithm, which can be used for a faster and more accurate response of the grid side converter control of a renewable energy source, especially under fault ride through operation. The adaptive dαβPLL is based on modifying the control parameters of the dαβPLL according to the type and voltage characteristic of the grid fault with the purpose of accelerating the performance of the phase-locked loop algorithm. The adaptive parameters are adjusted in real time according to the proposed fault classification unit, which permits a fast estimation of the type of the grid fault. The outstanding performance of the proposed adaptive PLL is verified through simulation and experimental results. Furthermore, the benefits of using the proposed adaptive PLL on the control of the GSC of RES are also demonstrated in this paper.