Speed, Torque and Voltage Performances of the Doubly Fed Induction Generator

Abstract

Wind as a renewable energy source over the last decade have received global attention as conventional energy sources are limited and cause some effects to mankind and his environment. The model of Doubly Fed Induction Generator (DFIG) based Wind Energy Conversion Systems (WECS) control with back-to-back converter has some drawbacks such as high weight, current harmonics and cost owing to the DC link capacitor circuitry. This paper evaluates the dynamic model of the DFIG driven by an Indirect Matrix Converter (IMC) in MATLAB/Simulink environment. The asynchronous machine was modeled in synchronous reference frame under stator flux orientation for which d-axis is aligned. An Indirect Space Vector Modulation (ISVM) was applied to control the matrix converter. Maximum Power Point Tracking (MPPT) control based on Indirect Speed Control (ISC) was applied to the wind turbine so as to track maximum power from the wind. The simulation results show the effectiveness of proposed system under different wind speed. For instance, when the wind speed is 10m/s the rotor speed is 0.94pu at steady state operation, after 6 seconds the wind speed increases to 12m/s while the rotor speed attained a new steady state operation of 0.97pu. The DFIG-based wind turbine system operates under sub-synchronous mode for the wind speed variation applied to wind turbine.