抑制风力机疲劳载荷的直接比例谐振独立变桨控制策略

Direct PR individual pitch control for wind turbine fatigue load mitigation

为减小由叶轮扫略面内风速不均衡导致的风力机疲劳载荷,提出一种无需科尔曼坐标变换的直接独立变桨控制策略。首先,基于风力机叶片旋转坐标系和轮毂静止坐标系之间的关系,分析了叶根弯矩谐波载荷对轮毂载荷的影响规律及其抑制机理;其次,为抑制风力机谐波载荷并减少传统独立变桨控制策略倾覆和偏航力矩之间的耦合影响,提出基于单个叶根弯矩的直接比例谐振(PR)独立变桨控制策略,通过建立周期时变叶片系统的平均线性化模型,设计了相位补偿器和控制器参数,并对所提控制策略在系统参数时变情况下的稳定性进行了频域分析;最后,建立基于Turb Sim-FAST-MATLAB/Simulink风电机组载荷及控制联合仿真模型,分析了某1.5 MW风力机在湍流风作用下的疲劳载荷特性以及不同变桨控制策略的疲劳载荷抑制效果。结果表明,与常规统一变桨控制策略相比,所提直接PR独立变桨控制策略能有效抑制风力机疲劳载荷,且其对机组有功功率输出几乎无影响。

A direct IPC（Individual Pitch Control） strategy without Coleman transform is proposed to mitigate the fatigue loads of wind turbine,which are induced by the nonuniform wind speed across the rotation plane.Based on the relation between the rotational reference frame of blades and the fixed reference frame of hub,the impact of blade harmonic load on the rotor hub load,as well as the corresponding suppressing mechanism,are analyzed. A control strategy based on direct PR（Proportional Resonant） IPC is proposed to mitigate the fatigue loads and to avoid the coupling between tilt and yaw moments. An averaged linear model of the periodically time-varying blade system is built,the phase compensator and the controller parameters are designed,and the stability of the proposed control strategy is analyzed with the time-varying system parameters in frequency domain. A combined load-control simulation model for the wind turbinegenerator system is established based on Turb Sim-FAST-MATLAB / Simulink,the fatigue load characteristics of a 1.5MW wind turbine in turbulent wind is analyzed and the effect of fatigue load mitigation is discussed for different pitch control strategies. Results show that,compared with conventional pitch control strategy,the proposed PR IPC strategy is more effective for the mitigation of wind turbine fatigue loads and has less impact on the active power output of unit.