A low‐order model for analysing effects of blade fatigue load control

Abstract

A new low‐order mathematical model is introduced to analyse blade dynamics and blade load‐reducing control strategies for wind turbines. The model consists of a typical wing section model combined with a rotor speed model, leading to four structural degrees of freedom (flapwise, edgewise and torsional blade oscillations and rotor speed). The aerodynamics is described by an unsteady aerodynamic model. The equations of motion are derived in non‐linear and linear form. The linear equations of motion are used for stability analysis and control design. The non‐linear equations of motion are used for time simulations to evaluate control performance. The stability analysis shows that the model is capable of predicting classical flutter and stall‐induced vibrations. The results from the stability analysis are compared with known results, showing good agreement. The model is used to compare the performance of one proportional–integral–derivative controller and two full‐state feedback controllers. Copyright © 2006 John Wiley & Sons, Ltd.

Aeroelastic Stability of Wind Turbine Blade Section Based on Beddoes-Leishman Model

“…Based on above fitted aerodynamic coefficients, balancing terms of order ε 1 leads to the linear approximations [1,3,4,5] , , and balancing terms of order ε 0 , the linear approximations of the unsteady aerodynamic coefficients are given [1] ,…”

“…The fitted aerodynamic coefficients can be expressed in polynomial formulas with N-order constant coefficients. The devise adopts a 4-DOF section model (see Fig.1) which is described by B. S. Kallesøe [1] . The deflection of the section is described by x, y and θ for the edgewise and flapwise directions and rotation respectively.…”

Vibration Control of Wind Turbine Blade Based on Data Fitting and Pole Placement with Minimum‐Order Observer

“…Some earlier studies involved the flap/lead-lag stability analysis based on eigenvalue problem [9] and stability control based on fuzzy PID algorithm and LQR controller [10], with the actual analyzed structure being single blade section. Members of our group investigated a variety of methods of intelligent control for flap/lead-lag flutter, also based on single blade section [2].…”

“…Since the cross-sections of different sizes experience different loads, the combined effects of different loads have far surpassed those of the same loads of the typical sections of the same sizes described in related references [1,2,9,10]. Therefore, the effectiveness of design parameters of crosssections of different sizes needs to be confirmed by aeroelastic stability analysis for safety reasons.…”

Adaptive Aeroelastic Suppression of a Wind Turbine Blade Using Trailing-edge Flap

“…A traditional way is using PID control algorithm, as Zeng adapted the proportional controller for flutter boundary expansion [9]. Moreover, as referring to advanced control, linear quadratic regulation (LQR) control was chosen as the optimization algorithm to suppress turbulence [8]. Beside aforementioned methods, another control technology is Adaptive Control, which is more powerful for the system with uncertain knowledge, and is much faster in adaptation to time-varying parameters.…”