Enhancement of Low Voltage Ride Through (LVRT) Capability of DFIG-Based Wind Turbines with Enhanced Demagnetization Control Model

Abstract

Since the stator of DFIG-based wind turbines is directly connected to the grid, it is dramatically affected by transient situations that may occur on the grid side. In order to meet grid code requirements, reactive power support must be provided to keep the DFIG connected to the grid during the transient state. To achieve this, Low Voltage Ride Through (LVRT) capability needs to be implemented in the grid-connected DFIG. Depending on the grid code requirements, different control models are used to provide LVRT capability. In this study, the demagnetization control model was developed in DFIG. In addition, the stator dynamic model has also been developed in order to decrease the disturbances that occur due to the stator being directly connected to the machine and to increase the calculation performance within the machine. While natural and forced flux models based on rotor electromotive force were developed in the demagnetization control model in DFIG, the stator electromotive force model was developed to ensure stator dynamics. In the study, it was seen that the demagnetization control model developed for transient situations such as balanced and unbalanced faults gave better results than the traditionally used model. The results obtained were evaluated in detail in terms of stability and oscillations.