变速与变桨协调的风电机组平滑功率控制

考虑到风电功率秒级波动对电网频率稳定的影响,需要对风电机组输出功率进行平滑控制。现有依靠风电机组实现风电功率平滑控制的方法大都存在频繁变桨的问题。为此提出了协调变速与变桨的平滑功率控制方法。该方法通过分离桨距角的上调和下调动作,将传统的基于变桨调节的恒转速(转速上限)控制转变为转速区间控制,使风轮机能够在任意桨距角下变速运行,从而更大程度地利用风轮机动能来平滑风电功率波动。因此,该方法在保证平滑控制效果的同时,能有效降低变桨动作频率和幅度,并减小变桨伺服机构的疲劳和叶片载荷。最后,基于风电机组模拟器的实验验证了所提方法的有效性。

Power Smoothing Control of Wind Turbine Generator via Coordinated Rotor Speed and Pitch Angle Regulation

Considering the fluctuation of wind power in seconds exerts an influence on the frequency stability of power grids, it is required to smooth the output power of wind turbine generators. Currently, the wind turbine-depended methods for smoothing wind power usually lead to frequent pitch adjustment, therefore, a power smoothing control method coordinating the rotor speed and pitch angle regulation is proposed. By separating the upward and downward regulation of pitch angle, the conventional constant-speed(upper speed limit)control is redesigned as the rotor speed range control so that the variable-speed operation at any pitch position is available and the kinetic energy buffer of wind rotor can be more adequately used to smooth wind power fluctuations. Correspondingly, while guaranteeing the smoothing effect, the proposed method can effectively reduce the frequency and amplitude of pitch actions, and alleviate the pitch servo fatigue and blade stress. Finally, the proposed method is verified by the wind turbine simulator based experiments.