DC Link Voltage and Power Flow Control of Doubly Fed Induction Generator in Wind Power System

Doubly Fed Induction Generator (DFIG) is the most commonly used type of induction generators nowadays in wind power industry where it is connected with grid directly through its stator and via dual-back-to-back converters through the rotor. This paper focuses on modeling and control of DC link voltage and the power flow between the generator and the grid. The effects of load current and reactive power changes are analyzed. To meet the target, the machine side converter (MSC) is modeled to regulate the stator active and reactive power whereas the grid side converter (GSC) ensures the regulation of the DC link voltage. The pulsewidth modulation (PWM) strategy is used to control the two converters. PI controllers are designed and applied in two reference frames: one oriented with the stator flux and the other with grid voltage, for the MSC and GSC respectively. MATLAB-Simulink software is used for modelling, simulation, and control.