风力发电机组的自适应转矩控制及载荷优化

针对变速变桨风力发电机组(variable speed variable pitch,VSVP)如何在低风速时最大限度捕获风能以及在额定风速以上降低传动链载荷进行研究。低风速时在研究了传统风能追踪控制策略的基础上,文中提出通过改变最优增益系数来追踪最佳风能利用系数的自适应转矩控制策略。同时针对风力发电机组传动链的扭转振动,提出了基于发电机转速反馈滤波的转矩纹波控制方式。以2MW变速变桨风力发电机组为验证对象,基于Blade软件平台对所采用的控制策略进行仿真研究。结果表明：所提出的自适应转矩控制策略能够更好的追踪最大功率点,同时采用转矩纹波能够降低传动链载荷     

基于神经元PID的风力发电机组独立变桨控制

针对传统统一变桨距控制策略存在的不足,基于风力机空气动力学原理,提出了基于神经元PID的独立变桨距控制策略,将测量的桨叶根部My方向载荷通过神经元PID控制算出d、q轴的桨距角,经反Park变换得到3个桨叶的附加桨距角,将其与统一变桨距角相加作为独立桨距角的设定值。并借助Fast软件平台以2MW变速变桨风力发电机组为例,仿真比较了独立变桨距控制策略与统一变桨距控制策略。结果表明,独立变桨距控制策略能有效保证在额定转速下机组输出功率稳定,且能有效降低风力发电机组各零部件的疲劳载荷。     

大功率风力发电机在全工况下的独立变桨距控制策略研究

研究在全工况下如何通过独立变桨距来减小机组关键零部件的疲劳载荷,考虑风剪造成的1 P不平衡载荷,采用LQR方法设计风力发电机的独立变桨距控制器,由于单纯采用基于状态空间的独立变桨距控制导致系统鲁棒性较差,因此引入带增益调度的统一变桨距控制,在统一变桨距的基础上附加独立变桨距。以5 MW变速变桨距风力发电机组为验证对象,基于NREL开发的FAST软件与Matlab 7.1/Simulink平台,在Simulink中实现风力发电机控制,并将控制信号返回FAST进行风力发电机的非线性仿真,在全工况下对独立变桨距控制策略与统一变桨距控制策略进行仿真验证。结果表明:相对统一变桨距控制,所提出的在全工况下带增益调度的独立变桨距控制,在保证额定转速下保持稳定的电功率输出的同时,能有效降低零部件疲劳载荷。     

基于激光测风雷达的风速前馈控制算法设计

文章提出了基于激光测风雷达的风速前馈控制算法设计,其特点是通过激光雷达准确有效地测得风力发电机组前方一定距离的风速、风向信号,并把所测信号引入到原有变桨控制算法中,设计了风速前馈控制器,实现变桨速率前馈补偿.以国产某1.5 MW风力发电机组设计为例,基于Bladed软件平台对所采用的算法进行仿真验证.结果表明,在来流作用于风轮之前,控制器就已经接收到超前信号,提前准备变桨动作,避免或大大减少风力发电机组的超速故障,降低了机组载荷,提高了风力发电机组在极端风况下的安全性,进而有助于提高发电量,改善风力发电机组的运行效率.     

基于免疫遗传算法的风力发电机组变增益PI控制器参数整定与优化

针对风力发电机组控制器参数在设计和优化过程中不易计算和整定的问题,首先通过Bladed软件模型线性化计算得出适用于参数整定和优化的风力发电机组线性化模型,然后基于免疫遗传算法整定PI控制器参数,根据风电场风速统计概率与Bladed软件辨识参数对普通和变增益PI控制器相关参数进行优化计算,建立了一套基于Bladed软件的风力发电机组变增益PI控制器参数整定与优化方法.结果表明:所提出的方法能够对风力发电机组变增益PI控制器参数进行有效的整定和优化,可为风力发电机组变增益PI控制器的设计与优化提供指导.     

风力发电机多域物理建模方法及独立变桨模糊控制器优化研究

针对独立变桨风力发电机,分析了风力发电机运行原理,基于以上原理在Matlab下分别建立了1.5MW独立变桨风力发电机的监测控制系统、独立变桨距控制系统、偏航控制系统、液压执行器系统和电网系统的物理模型,设计了独立变桨距控制模糊PI控制器,与传统PI控制器进行了仿真对比。仿真结果表明了该物理模型的正确性,对比结果表明,模糊PI控制器不仅能提高节距角跟踪精度而且能够稳定输出电压和输出功率,同时也减小了拍打震动和桨叶载荷。     

基于混合灵敏度H_∞的海上风力发电机组变桨控制及振动抑制

针对海上风力发电机组输出功率波动大和塔架振动明显的问题,设计了混合灵敏度H∞变桨控制器,并引入塔架前后加速度反馈控制,基于SUT-3000双馈风力发电机组模型,利用GH_Bladed软件进行仿真验证。仿真结果表明,在该控制策略作用下,海上风力发电机组输出功率比传统PI控制方法波动更小,保证了海上风力发电机组在高风速运行时输出功率的稳定性,同时降低了塔架前后振动响应。     

基于削峰调节的风电机组载荷优化控制技术

大型变速变桨风力发电机组在变桨距控制过程中,由于额定风速附近推力呈尖峰变化趋势,导致机组的极限载荷较大,针对该问题提出一种修正变桨动作的削峰调节控制器。将该功能编程写入外部控制器,通过Bladed软件设置不同的工况,对某3 MW风电机组进行仿真验证,仿真结果表明该控制器能够改善变桨控制的动态特性,降低关键部件的载荷,提高机组的可靠性和安全性。     

台风时变桨风机损坏原因及对策研究

台风工况时,变桨风机顺桨停机,整机气动载荷随风向时变,在台风交变载荷作用下,已运营的风力发电机组容易出现批量部件损坏,影响风力发电机组的全寿命周期.以2013年9月天兔台风影响的广东东部沿海山地风场为背景,参考背景风场风机设计标准,拟定考虑动态湍流的极端风速模型,选择某2 MW变桨风力发电机组为算例,分别计算该机型在台...     

基于变桨距控制策略的异步风电机组暂态稳定性研究

为了提高和改善在电网故障下并网风电机组的暂态稳定性,该文以并网笼型异步风力发电机组为例,考虑风力机传动链柔性带给机组振荡的影响,在典型变桨控制策略的基础上提出了一种增加以风力机转速为控制量的分阶段控制策略.通过建立并网异步风力发电机组的电磁暂态模型,基于Matlab/Simulink仿真平台,应用改进的变桨距控制策略,对电网三相对称短路故障下并网异步风力发电机组的暂态运行特性进行了仿真,并将其结果和多种不同变桨控制策略以及无功补偿策略的结果进行了比较.仿真结果验证了该文提出的变桨距控制策略能有效改善风力发电机组的暂态稳定性.     

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。     

风 风能 风力发电——21世纪新型清洁能源

一风的一般属性１风的形成风是人们非常熟悉的一种自然现象，人人都能感觉到它的存在。春风和煦，给万物带来生机；夏风吹拂，使人心旷神怡；秋风送爽，带来丰收的喜悦；冬风呼啸，迎来漫天飞雪。那么风是怎样形成的呢？众所周知，人类生活的地球表面被大气所包围，来自太阳的辐射不断传送到地球表面，因太阳辐射受热情况不同，地球表面各处的气温不同。在影响气压高低的因素中，气温起着最重要的作用。温度高的地区空气受热上升，气压减小；温度低的地方，空气下降，气压增大，于是产生了气压差。和水往低处流一样，空气也从气压高处向气压…     

Evaluation of wind farm efficiency and wind turbine wakes at the Nysted offshore wind farm

Here, we quantify relationships between wind farm efficiency and wind speed, direction, turbulence and atmospheric stability using power output from the large offshore wind farm at Nysted in Denmark. Wake losses are, as expected, most strongly related to wind speed variations through the turbine thrust coefficient; with direction, atmospheric stability and turbulence as important second order effects. While the wind farm efficiency is highly dependent on the distribution of wind speeds and wind direction, it is shown that the impact of turbine spacing on wake losses and turbine efficiency can be quantified, albeit with relatively large uncertainty due to stochastic effects in the data. There is evidence of the ‘deep array effect’ in that wake losses in the centre of the wind farm are under‐estimated by the wind farm model WAsP, although overall efficiency of the wind farm is well predicted due to compensating edge effects. Copyright © 2010 John Wiley & Sons, Ltd.     

Dynamic wind estimation based control for small wind turbines

We introduce a novel scheme for small wind turbines that gives dynamic estimation of wind speed from rotor angular velocity measurements. The estimation proceeds in two different dynamic observers, one giving a valid estimate for higher Tip Speed Ratios (TSRs) and which we call the Upper Wind Estimator (UWE) and the other called the Lower Wind Estimator (LWE) valid for lower TSRs. The meaning of “higher” and “lower”, and the precise regions of validity, are quantified. We further propose a coordinated control scheme using the UWE. Simulations are presented showing closed-loop performance of the turbine and the estimators both in the optimal TSR regulation condition, and the dynamic power-shedding condition caused by a wind gust. An analytic analysis of closed-loop stability and of the convergence and bias properties of the estimator is provided. Empirical data showing performance on a real turbine is also presented.     

分散式风力发电机组的电压控制

风电的分散式开发不同于大规模开发和分布式开发,由于分散风电靠近负荷中心,直接接入配电网,且不加装无功补偿调节装置SVC,配网中较大的电压波动给分散风电的并网运行带来影响。文章讨论了配网对分散风电的电压控制特点和要求,结合风电机组无功控制能力,并推导出满足配网电压调节要求的风电机组无功控制范围和对机组设备的要求。     

适用于特殊风区的风电机组塔架的再设计

由于IECⅠ级机型性能不能满足超Ⅰ类风区的要求,因此以IECⅠ级机型塔架的结构为基础,对其进行了再设计,并利用有限元方法,对再设计后的塔架的静强度、模态、稳定性进行了分析。分析结果表明:再设计后的塔架的强度、固有频率和刚度均满足要求;以满足强度、频率特性和刚度为约束条件,以减轻重量、降低成本为目标的塔架的再设计是可靠的。     

某风电场风力发电机组故障诊断

为了准确判断风电机组的运行状态及故障,提出了基于常规分析—振动幅值分析—波形频谱分析的故障诊断流程,阐述了针对风电机组的幅值分析方法和波形频谱分析方法,并通过对某机组异响的根源探究实例,准确地诊断出机组异响来源于齿轮箱太阳轮,可为风电机组故障诊断技术提供依据。     

Simulation of hourly wind speed and array wind power

Statistical summaries of wind speed are sufficient to compute many characteristics of turbine-generated power, such as the mean, variance and reliability of various power levels. However, a wind speed time series is necessary to produce a sequence of power values as used for investigating load matching and storage requirements. Since a long historical record of wind speed may not be available at a wind turbine candidate site, it is desirable to be able to generate a simulated numerical sequence of hourly wind speed values. Two such approximate procedures are developed in this paper. One procedure generates sequential wind speed values at a site based on the Weibull parameters of hourly wind speed and the lag-one autocorrelation of hourly wind speed values. Comparison with historical data at a site is made. The second procedure generates sequential hourly wind power values for a regional array of wind turbines. It utilizes the typical site wind characteristics, the spatial and lag-one cross correlation and autocorrelation of hourly wind speed values and an equivalent linearized relationship between array average wind speed and array power. Comparison with results for six different wind turbines in three different regional arrays indicates good agreement for wind power histograms, autocorrelation function and mean persistence.     

Characterization of wind speed data according to wind direction

Knowledge of the wind speed distribution and the most frequent wind directions is important when choosing wind turbines and when locating them. For this reason wind evaluation and characterization are important when forecasting output power. The data used here were collected from eleven meteorological stations distributed in Navarre, Spain. We obtained data for the period extending from 1992 to 1995, with each datum encompassing 10 minutes of time. Wind speed data of each station were gathered in eight directional sectors, each one extended over 45 degrees according to the direction from which the wind blows. The stations were grouped in two blocks: those under the influence of the Ebro valley and those in mountainous areas. For each group the Weibull parameters were estimated, (according to the Weibull probability paper because the Weibull distribution gives the best fit in this region). Kurtosis and skewness coefficients were estimated as well. The Weibull parameters, especially the scale parameter c, depend strongly on the direction considered, and both Weibull parameters show an increasing trend as the direction considered moves to the more dominant direction, while both kurtosis and skewness show a corresponding decreasing trend.     

A new formulation for rotor equivalent wind speed for wind resource assessment and wind power forecasting

The spurt of growth in the wind energy industry has led to the development of many new technologies to study this energy resource and improve the efficiency of wind turbines. One of the key factors in wind farm characterization is the prediction of power output of the wind farm that is a strong function of the turbulence in the wind speed and direction. A new formulation for calculating the expected power from a wind turbine in the presence of wind shear, turbulence, directional shear and direction fluctuations is presented. It is observed that wind shear, directional shear and direction fluctuations reduce the power producing capability, while turbulent intensity increases it. However, there is a complicated superposition of these effects that alters the characteristics of the power estimate that indicates the need for the new formulation. Data from two field experiments is used to estimate the wind power using the new formulation, and results are compared to previous formulations. Comparison of the estimates of available power from the new formulation is not compared to actual power outputs and will be a subject of future work. © 2015 The Authors. Wind Energy published by John Wiley & Sons, Ltd.