Improving Analysis of Low Voltage Ride Through Capability in Turbines Connected to The Brushless Doubly Fed Induction Generator (BDFIG) under Fault Conditions

Abstract

The connection of wind farms to the grid and their dynamic behavior under different conditions is a real challenging issue which resulted in providing new instructions for the network. One of the important topics related to grid standards is Low-Voltage Ride-Through capability. In recent years, The application of Brushless Doubly Fed Induction Generator (BDFIG) in the wind farms has drawn the attention of researchers. This generator has more advantages than other common generators, including the Doubly Fed Induction Generator (DFIG). In this paper, the performance of the BDFIG under fault conditions in the grid is examined and monitored in order to improve LVRT while considering the dynamic model of the BDFIG connected to a wind turbine. In this method, the reactive power and speed are controlled for stable performance of the generator under various grid conditions. A converter is used to connect the stator control winding to the power grid, which DC link voltage is adjusted using multiple PI controllers under fault conditions. In addition, two controlling systems based on the conventional PI controllers are proposed to control the generator side converter and the wind turbines step angle. The results demonstrate good dynamic performance of the examined generator under different grid conditions achieved by the proposed controlling method without using any additional hardware such as a Crowbar.