Direct Speed Control of a 9 MW DFIG Wind Turbine

Abstract

In the present work, a control strategy for Maximum Power Point Tracking (MPPT) of a wind turbine based on a Doubly Fed Induction Generator (DFIG) is described. This strategy is developed according to the theory of Di-rect Speed Control (DSC) which includes a state observer. This strategy con-siders the Low Shaft Speed (LSS) as an input and the Iqr reference current as the output. This control mechanism allows monitoring the MPPT; thus, changing the Power coefficient (Cp) to its optimal value during the operation of the wind turbine. The controller, among its main features, is configured to work with the incorporation of different wind inputs; fact that permits evaluating the system response to disturbances and variations. For simulations tests, a 1,5 MW wind turbine has been modeled in Matlab and Fatigue, Aero-dynamics, and Structures and Turbulence FAST software. The strategy has been compared to a PI MPPT controller and has demonstrated improvements in terms of speed and output power extraction.