Individual pitch control of doubly-fed wind turbine generator based on blade element theory

Abstract

The premise of collective pitch control is that wind speed is the same in the rotor plane, but wind shear and tower shadow makes wind speed in the rotor rotating plane changing differently. It affects the corrective pitch control greatly and increases the fatigue load. This paper model 1.5MW doubly-fed WTG (wind turbine generator) for individual pitch control, and analyze the main reason of periodic load fluctuation. Then individual pitch control based on blade element theory was researched combining the actual of the load is difficult to measure. Pitch angle was distributed by weight coefficient to realize individual pitch control. The weight coefficient was computed according to the wind speed with consideration of trailing vortex, wind shear and tower shadow. Simulations indicate that the proposed individual pitch control method not only meet the basic power control request but also reduce fluctuation of load, so it can solve the problem of fatigue load and prolong the lifetime in process of development to large-scale WTG.