【作者】 韩雪姣；

【导师】 童亦斌；

【作者基本信息】 北京交通大学 ， 电气工程， 2012， 硕士

【摘要】 风电机组建模仿真是一种研究风电机组基本原理、控制技术、协调优化的重要手段,近年来基于建模仿真的风电技术研究得到了越来越多的关注。随着风电机组单机容量的增大、风轮半径的增加,大型风电机组风轮受风不均匀特性和叶片不平衡特性对风电机组机械部件振动以及并网电能质量的影响越来越严重,因此,本文围绕风切变、塔影效应、叶片不平衡对风电机组性能的影响展开研究。首先,建立了风电机组模型。根据风电机组的基本结构和运行原理,分别建立了风力机、传动链、发电机、变流器、控制系统的模型。其中重点建立了基于叶素动量理论的风力机模型、变流器的简化功率模型及直流环节功率电压模型。其次,分析了气动载荷特性。分别建立了风切变、塔影效应、叶片不平衡的模型,并根据所建风力机模型计算得到三种因素单独作用时及联合作用时的气动载荷(切向转矩、轴向推力、主轴作用力),并从时域和频域两个角度,定量分析了三种因素造成的切向转矩波动和主轴作用力波动,进而分析了其对风电机组相关机械部件振动的影响,为机械降载设计提供依据。最后,研究了并网功率平稳控制技术。利用所建立的变流器模型和直流环节模型,根据气动载荷特性分析得出的结论,对传统的并网控制策略进行改进,提出了基于输入功率前馈的并网控制策略,通过在直流电压指令中叠加功率波动信息来吸收输入功率的波动,从而利用直流电容的储能作用抑制并网功率的波动。将传统并网控制策略与改进并网控制策略进行对比分析,仿真结果验证了改进控制策略的有效性。本文通过建模仿真的手段,定量分析三种因素造成的切向转矩波动；进而一方面分析转矩波动对相关机械部件振动的影响,为机械降载设计提供依据,另一方面针对切向转距波动引起的输入功率波动,提出改进的并网控制策略,抑制三种因素造成的并网功率波动,提高并网电能质量。仿真结果验证了理论分析的正确性和所提出控制策略的有效性。更多还原

【Abstract】 Modeling and simulation have been an important method for the study on the basic principle, the control technology, and the coordinated optimization for wind turbines. At present, the influence of uneven wind speed and unbalanced blades on the wind turbine characteristics and the grid connected power quality is more and more serious, so this paper analyzes the influence of uneven wind speed and unbalanced blades on the wind turbines and puts forward an improved grid connected control strategy to mitigate the fluctuation of the grid connected power based on the wind turbine model by simulation.First of all, the wind turbines models are built. The wind turbine aerodynamic part, driving chain, generator, converter and control system are modeled based on the structure and operating principle of wind turbines. The wind turbine aerodynamic model based on the BEM (Blade Element Momentum theory), the equivalent power model of converter and the power-voltage model of DC link are modeled especially according to the study purpose of this paper.Secondly, the aerodynamic characteristics are analyzed. Considering wind shear, tower shadow effect and the unbalanced blades, the aerodynamic loads model of large scale wind turbine are built based on the BEM; by analyzing the simulation results of aerodynamic loads in time domain and frequency domain, the influence of wind shear, tower shadow effect and unbalanced blades on the aerodynamic loads characteristics and the resonance characteristic of relative mechanical components are obtained.Finally, the stable control strategy of grid connected power is studied. The influence of wind shear, tower shadow effect, and unbalances blades on grid connected power are analyzed based on the model built before, and the classical grid connected control strategy is improved to mitigate the influence of the three elements; the classical grid connected control strategy and the improved one are both simulated on the model platform, and the simulation results verify the validity of the improved control strategy.更多还原