A Control Approach Based on Fuzzy Logic for Grid-Interfaced Wind Energy Conversion System

Abstract

The focus of documented research in this paper is the Low Voltage Ride Through (LVRT) capability of electric grid connected Wind Energy Conversion System (WECS) using Takagie-Sugeon (TS) type fuzzy controller. The increased deployment of Wind Turbine technology in modern power systems makes the LVRT capability of WECS one of the important research topics. Consequently, to avoid power network instability, power utilities defined technical specifications for modern WECS. These specifications are known as Grid Codes and are further categorized as static and dynamic requirements. The LVRT capability falls under the category of dynamic requirements of Gird Codes. The most frequently and extensively used generator for wind turbines is the Doubly Fed Induction Generator (DFIG) due to its lower cost, less power loss, variable speed, and four-quadrant operation. However, DFIG based WECS are highly sensitive to electric network disturbances because the stator of the DFIG is directly connected to the power system. Therefore, in this research study, the main attention is drawn towards the control of power electronic interface i.e., grid side converter of DFIG based WECS. The simulation results of symmetrical and asymmetrical faults, with different fault injection locations, are analyzed in order to provide a comprehensive understanding of the impact of electric grid disturbances on WECS. The results of the TS-type fuzzy controller are compared with the PI controller to illustrate the effectiveness of the fuzzy controlled DFIG based WECS. The aforementioned comparison of simulation results demonstrated that the transient stability of WECS is considerably improved by using TS type fuzzy controller. Thus, it is concluded that the TS-type fuzzy controller can be an efficient and promising solution for modern DFIG based WECS.