风力发电机叶片振动方程及固有频率

分析了风力发电机转子叶片所受的外力和外力矩，给出了叶片俯仰振动、扭转振动和摆动振动方程及相应的一阶振动固有频率。     

大型风力发电机组塔架顶端的水平位移的计算

计算大型风力发电机组的整体稳定性和动态特性的关键是要计算出机组顶端的水平位移,由于大型风力发电机组结构通常比较复杂,塔架均采用变截面形式,各截面的刚度并非常数,因此使计算过程变得复杂、繁琐,以变截面塔架结构为例,根据刚度相等的条件,推导出变截面塔架结构在横向力、弯矩及均布载荷作用下对应的当量惯性矩的计算公式,从而可简便地求出其顶端的水平位移。     

大型风力发电机组自振频率的分析

应用集中质量法的基本原理和方法对复杂的大型风力发电机组结构进行合理的简化,建立相应的动力学模型和运动方程分析机组的自振特性,通过求解线性齐次方程组导出机组最主要的n阶自振频率。经验证,此法简便实用且能获得较为满意的精度,可为大型风力发电机组结构动态设计提供参考。     

大型风力发电机组独立桨叶控制系统

设计出独立桨叶控制系统的机构方案，依据空气动力学分析，提出模糊控制结合以桨叶空间方位角作为主体因素的加权系数的控制策略，建立了系统模型，仿真结果表明，在风速高于额定风速时，作用在桨叶上的负载波动大为减小，输出功率维持在额定功率附近。     

大型风力发电机组高强度螺栓预紧力矩的探讨

高强度螺栓作为风力发电机组主要零部件的重要联接元件之一,其联接的可靠性,将直接关系到风力机运行的安全。实际应用过程中,由于影响高强度螺栓联接可靠性的因素较多,稍有不慎就可能危及风力机运行的安全。对直接影响高强度螺栓联接可靠性的预紧力矩和相关的安装工艺提出一些初步的看法,供相关人员参考。     

基于Riccati传递矩阵法的汽轮发电机组扭振固有频率计算分析

将连续质量模型的Riccati传递矩阵法应用于汽轮发电机组轴系扭振的固有频率计算中，通过理论分析及具体算例运算，表明该方法既简便又具有较高精度，而且采用此方法计算时与模型划分单元数目无关，是一较为理想的汽轮发电机组轴系扭振频率计算方法。     

双馈变速恒频风力发电机组两种传动链动力学模型建模及分析

以双馈变速恒频风力发电机组两种传动链动力学为研究对象,应用拉格朗日能量法及多体动力学基本原理,建立两种传动链的动力学模型,分析主轴轴承数目的变化和齿轮啮合时弹性变形引起的固有频率的变化,为风力发电机组的设计和应用提供理论依据和技术支撑。     

大型风力发电机组机舱座极限强度计算方法与应用

针对大型风力发电机组机舱座的热点应力分布和应力值的随机变化问题,利用有限元理论和线性叠加理论,分析了大型风力发电机组机舱座在其设计寿命周期内所承受的极限应力,结合载荷遍历法逐一求解机舱座的热点处应力值,从中选出最大应力值作为机舱座的设计参考值,并与一般的极限载荷法进行比较。结果表明,采用载荷遍历法所得的应力值较一般的极限载荷工况法更接近热点的实际值,更准确地反映了热点处的应力值,为结构设计的可靠性和优化提供了理论依据。     

大型风力发电机组地震载荷计算方法研究

随着国家大规模开发风力发电,风力发电机组安全性逐渐受到重视.近年来全国地震时有发生,由于地震很难预测,并且具有很强的破坏性,风力发电机组在地震情况下的安全性必须在设计中考虑.文章介绍了风力发电机组地震设计标准,分析了地震载荷计算原理.最后根据2 MW陆上双馈风力发电机组,分析了地震载荷对风力发电机组各个部件设计的影响,为风力发电机组地震载荷计算提供了参考经验.     

风电叶片固有频率相关性分析新方法

为进行三维风电叶片振动系统固有频率相关性分析,采用MATLAB和ANSYS共同建立了风电叶片三维有限元参数模型,并分析了叶片固有振动特性.考虑系统随机结构参数对风电叶片固有振动的影响,运用将Monte Carlo与ANSYS相结合的方法对叶片固有振动特性进行相关性分析,进而判断其对随机结构参数的敏感性,形成了一种叶片结...     

大型风力发电机组塔架联接螺栓最大工作载荷的计算

通过风力发电机组塔架联接螺栓所受的载荷种类、特点,对塔架联接螺栓受力状态进行分析,并根据螺栓的分布规律推导出联接螺栓最大工作载荷的精确、简便的计算公式,可供相关设计人员参考.     

大型水平轴风力机噪声的测量

阐述了风力机噪声的传播、衰减和针对噪声的评估准则,以及风力机噪声的测量原理。针对风力机噪声测量测点布置进行了优化,给出了风力机噪声的测量实验方案和装置,并且采用自由声场法对风力机噪声进行了测量,得出了风力机噪声和周围环境噪声之间的合成声压级。     

水平轴风力机塔架的频率和振型特性实验研究

为了研究风力机塔架的振动特性,文章利用动态信号采集分析系统,对水平轴风力机塔架进行了实验模态分析和运行模态分析测试,得到了塔架静止与振动两种工况下的固有频率与模态振型,分析了塔架的振动特性。通过对风力机振动信号的频谱分析发现,风速小于10 m/s时,只能激励起塔架挥舞方向与摆振方向的二阶模态;通过对风力机塔架的模态分析发现,风力机发生振动,塔架固有频率与模态振型发生小幅度改变;随着风速和振动烈度的增大,塔架模态参数的变化幅度随之增大。该研究可以为风力机塔架优化设计提供借鉴。     

风电场风电机组的接地设计

较系统地介绍了风电场风电机组对接地电阻的要求、接地设计思路及方法,并提供实际工程中接地网布置图实例作为参考。     

Sensitivity of southern California wind energy to turbine characteristics

Using output from a high‐resolution meteorological simulation, we evaluate the sensitivity of southern California wind energy generation to variations in key characteristics of current wind turbines. These characteristics include hub height, rotor diameter and rated power, and depend on turbine make and model. They shape the turbine's power curve and thus have large implications for the energy generation capacity of wind farms. For each characteristic, we find complex and substantial geographical variations in the sensitivity of energy generation. However, the sensitivity associated with each characteristic can be predicted by a single corresponding climate statistic, greatly simplifying understanding of the relationship between climate and turbine optimization for energy production. In the case of the sensitivity to rotor diameter, the change in energy output per unit change in rotor diameter at any location is directly proportional to the weighted average wind speed between the cut‐in speed and the rated speed. The sensitivity to rated power variations is likewise captured by the percent of the wind speed distribution between the turbines rated and cut‐out speeds. Finally, the sensitivity to hub height is proportional to lower atmospheric wind shear. Using a wind turbine component cost model, we also evaluate energy output increase per dollar investment in each turbine characteristic. We find that rotor diameter increases typically provide a much larger wind energy boost per dollar invested, although there are some zones where investment in the other two characteristics is competitive. Our study underscores the need for joint analysis of regional climate, turbine engineering and economic modeling to optimize wind energy production. Copyright © 2012 John Wiley & Sons, Ltd.     

兆瓦级风力发电机叶片动力学响应分析

应用现代柔性多体动力学和有限元数值分析相结合的理论建立风力机旋转叶片结构的系统动力学方程,并对微分方程数值求解的方法进行了研究;运用Bladed软件对1.5 MW风力发电机进行建模,分析叶片的结构动力学响应,得到系统的固有频率以及正常工况、启动工况和停车工况下3叶片挥舞方向和摆振方向的振动位移情况,判断风力发电机组运行的稳定性。     

Electromagnetic energy harvester for monitoring wind turbine blades

The long composite blades on large wind turbines experience tremendous stresses while in operation. There is an interest in implementing structural health monitoring (SHM) systems inside wind turbine blades to alert maintenance teams of damage before serious component failure occurs. This paper proposes using an energy harvesting device inside the blade of a horizontal axis wind turbine to power a SHM system. The harvester is a linear induction energy harvester placed radially along the length of the blade. The rotation of the blade causes a magnet to slide along a tube as the blade axis changes relative to the direction of gravity. The magnet induces a voltage in a coil around the tube, and this voltage powers the SHM system. This paper begins by discussing motivation for this project. Next, a harvester model is developed, which encompasses the mechanics of the magnet, the interaction between the magnet and the coil, and the current in the electrical circuit. A free fall test verifies the electromechanical coupling model, and a rotating test examines the power output of a prototype harvester. Copyright © 2013 John Wiley & Sons, Ltd.     

Model‐based control addition to prescribe DFIG wind turbine fast frequency response

This paper investigates the physical capability of double‐fed induction generator (DFIG) wind turbines for inertial support of frequency response. Frequency stability is modeled using the DFIG electromechanical and generator controller dynamics, and a destabilizing effect is demonstrated in low‐inertia systems. To improve response, a synchronous reference frame DFIG controller is proposed that acts by following low‐frequency grid dynamics and adds a fast acting proportional plus integral (PI)‐controlled frequency‐responsive component to existing qd current commands. The proposed controller is derived in a straightforward manner using only the DFIG dynamic equations and is designed using pole/zero placement techniques. Laboratory experiments using a micro‐scale DFIG wind turbine with hub‐emulating flywheel prove better capability for transient frequency regulation even under extreme load change. The result is a DFIG controller that balances the appearance of transients in electrical and mechanical systems. Value is achieved in providing immediate continuous inertial response to support load change. The proposed frequency response can improve the use of existing physical inertia from wind turbines.