摘要
常规认为的额定风速以下的恒定最优桨距角在机组恒转速段并不一定是最优的。恒转速段的最大功率跟踪问题等同于特定转速下的气动转矩最大化问题,以提高发电量为目标分析了在两个恒转速段内切向力系数及法向力系数与桨距角的定性关系。分析表明,在恒最低转速段通过合理地正调桨距角可以提升切向力系数并提高发电量,且可减轻轴向推力等载荷;在恒最高转速段通过合理地负调桨距角可以提升切向力系数并提高发电量,但会增大轴向推力载荷;在两个恒转速段内特定风速下均存在其对应的最优桨距角,且最优桨距角随风速单调变化。针对最优桨距角难以直接量化的问题,根据定性分析结果推断出最优桨距角的合理表达式,并给出了表达式中参数的离线辨识方法。最后采用专业软件Bladed中的商用机组实际参数模型,从稳态和动态两方面对恒转速区提高发电量的变桨策略进行了验证,仿真结果很好地证明了分析的正确性,从而更好地指导机组提高发电量。
The conventional optimal pitch angle below the rated wind speed is not necessarily optimal under constant speed region of the turbine. Tracking maximum power equals to tracking maximum aerodynamic torque in the constant speed region. In order to improve power production, the qualitative relationship between tangential/thrust force coefficient and pitch angle under two constant speed regions were analyzed. The results show that during the constant lowest speed region, the tangential force coefficient can be improved by reasonable pitch action with positive direction so as to improve the power production, with the thrust load decrease; During the constant highest speed region, the tangential force coefficient can be improved by reasonable pitch action with reverse direction so as to improve the power production, but would increase the thrust load; There is a corresponding optimal pitch angle for a specific wind speed in two constant speed regions, and the optimal pitch angle changes with wind speed with monotonicity. As the optimal pitch angle is difficult to quantify directly, a reasonable expression of the optimal pitch angle was deduced according to the qualitative analysis, and the method to identify the parameters in the expression was also given. Finally, the study was verified by a commercial turbine model on professional software GH Bladed, from both steady aspects and dynamic aspects. The simulation results fits the analysis quite wel l , so as to offer a better guide for improving power production.
出处
《电工技术学报》
EI
CSCD
北大核心
2017年第1期58-68,共11页
Transactions of China Electrotechnical Society
基金
上海市科委项目(11dz1200204)
国家电网公司总部科技项目(SGHB0000KXJS1400040)资助
关键词
风电机组
恒转速段
最大功率跟踪
发电量
变桨控制
全风况
Wind energy conversion （ WECS） , constant speed region, maximum power point tracking （MPPT） , power production, pitch control, overall wind speed range
