Modeling and control of a doubly-fed induction generator in a wind turbine

Abstract

Nowadays, technology for management of wind energy is developing rapidly. Over thelast few years variable speed wind turbines have overwhelmed their respective fixed-speed, mainly due to the improved performance they offer. The variable speed doubly-fed induction generator (DFIG) is one of the most frequently used in modern gridconnected wind turbines, because it has the ability to fulfill the grid requirements. DFIGallows a precise control of frequency range, voltage and power generated.For this purpose, this paper will focus on the analysis, modeling and control of theoperation of a DFIG moved by a wind turbine and connected to the electricity grid. Anonlinear mathematical model of DFIG and its equivalent simplified model aredescribed for simulation. It is also designed a rotor vector control and a control for theenergy fed to the grid. A 2MW wind turbine is analyzed and simulated throughMatlab/Simulink. Different reference frames will be used during the modeling and asuitable power control method over the machine operation will be introduced.Furthermore, it stresses the importance of vector control based on stator flux orientedtechnique in order to manage the active and reactive power effectively.