Power Quality Improvement of DFIG based Wind Energy Conversion System

Abstract

Renewable Energy Resources have attracted worldwide attention due to soaring prices, newlinefast depletion of fossil fuels and climate change concerns. These are regarded as important in enhancing energy security by reducing dependence on fossil fuels and decreasing Green House Gas (GHG) emissions. In recent years, wide-ranging research has been carried out to exploit the potential of renewable energy sources, particularly in wind, solar and tidal energy. A wind power generation scheme out of all renewable energy sources is the most competitive, environmentally clean and secures the system. During the last decades, the concept of a variable-speed wind turbine (WT) has been receiving increasing attention due newlineto the fact that it is more controllable and efficient, and has good power quality. newlineThe various generating systems considered are Wind Energy Conversion Systems (WECSs). Different configurations of autonomous variable speed WECS, using Doubly Fed Induction Generator (DFIG) and their control strategies are proposed to address the newlineissues of voltage and frequency control (VFC) with the change in wind speed. The general newlineoutlining philosophy of the proposed systems is centered on stator windings in a DFIG are newlinedirectly connected to the grid while the rotor windings are connected to the grid via back to back converters ac-dc-ac converter with a battery. In this work, The complete standalone and grid-connected system has been incorporates by the mathematical modeling of the wind speed model, the aerodynamic model of the wind turbine, models of the DFIG, three-phase two-level PWM voltage source converter models, transformer and the controller models are developed in MATLAB simulink environment. The proposed chopper-controlled external rotor resistance technique has been carried-out on DFIG-based fixed speed wind turbine to regulate the voltage and frequency. But in this technique the more energy is lost through external rotor resistance in the form of heat.