A MATLAB Based Analysis of Direct Torque Control of a Matrix Converter Fed Grid Connected Doubly Fed Induction Generator

Abstract— Doubly Fed Induction Generator (DFIG) is the most popular variable speed generator for wind energy application due to its superior performance, lower cost and control flexibility. The DFIG has been widely used and researched in wind generator application. Instead of back-to-back converters, matrix converter (MC) can be a good alternative for connecting the DFIG rotor to the grid. This paper presents a matrix converter based control for a variable speed constant frequency (VSCF) DFIG. Design of DFIG based wind power generation system with the help of matrix converter is analyzed by means of MATLAB/SIMULINK block set.

Index terms— Doubly Fed Induction Generator, Matrix Converter,wind energy, Wing Energy Conversion System, Space vector modulation.

NOMENCLATURE ws ,w, wr Synchronous, shaft and slip speed of the DFIG Stator and rotor flux vector magnitudes δ Angle between the stator and the rotor flux σ Leakage factor Ls , Lr ,Lm Stator self inductance, rotor self inductance, and magnetizing inductance referred to the stator. Rs , Rr Stator and rotor resistance referred to the stator. Qs Stator reactive power Te Electromagnetic torque

I. INTRODUCTION

The renewable energy sources are one of the biggest concerns of our times. High prices of oil and global warming make the fossil fuels less and less attractive solutions. Wind power is a very important renewable energy source. DFIG is most commonly used generator because it has more advantages than PMSG and SCIG [8]. In DFIG, both stator and rotor having field windings. So significant power transfer between shaft and electrical system. And varying speed of machine shaft is limited to around synchronous speed. In DFIG power converters are connected in rotor to grid or load, only slip power is transmitted through rotor to grid, so it required only small ratings of converters [3].
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