风力发电传动系统的建模与数字模拟研究

通过分析风力发电机组中传动系统的特性,针对不同类型的风力发电机组提出了灵活的传动系统建模方法(包括4种模型:刚性轴感应发电机模型、柔性轴感应发电机模型、刚性轴变速发电机模型和柔性轴变速发电机模型),并采用数字模拟方法在软件中加以实现,与商业风力机计算分析软件GH-Bladed中的风力发电系统运行结果进行对比,验证了模型的准确性,运行结果表明,该文提出的建模方法能够满足不同传动系统的惯性要求,并且能方便的在软件中根据实际风力机参数进行模型选择和参数设置,为实验室模拟风力发电系统提供了理论依据和模拟方法。     

基于MATLAB的风力发电机组建模和仿真研究

变桨距控制技术是风力发电机组提高对风能的利用的有效方法,由于外界环境的随机性和控制变量的多样性,风力发电系统是一个非线性的系统,其数学模型的建立和仿真是一个难点。本文基于Matlab软件平台,采用机理建模法建立了风力发电机组的各个分系统的子模型,组合成整个机组的数学模型,并采用PID控制算法实现风力发电机组在不同风速下对风能利用的最大化,仿真结果验证了系统模型和控制算法的正确性,为风机控制的创新奠定了理论基础。     

风力发电机组仿真演示系统研究与开发

针对风力发电系统的试验研究受到自然环境和现场条件限制的问题,基于Matlab/Simulink仿真平台,采用面向物理对象建模方法,根据风力发电系统的物理结构和运行特性对其仿真建模,开发了风力发电机组仿真演示系统,并将风力发电系统分解为若干个独立运行的子系统,通过控制结构连接整体。实例表明,本系统能够准确描述整台风力发电机组的动态行为,适合于教学仿真演示及控制技术研究。     

基于Matlab/Simulink的风力机性能仿真研究

随着风力发电技术的发展,变速风力发电技术成为了风力发电发展的趋势。风力机作为变速风力发电机组的重要部分,其性能影响到风力发电机组的整体性能。根据变速风力机的静态性能特点,采用Matlab／Simulink软件对其进行建模,并给变速风力发电机组风力机输入模拟变速风速进行仿真研究,给出了风力机的静态性能数据和仿真波形。结果表明：通过调节影响风力机性能的各因素,保持发电机的转速与主导风速之间特定的最优比例系数,使得风力机保持在最佳叶尖速比下运行,跟随变速风速可实现最大风能捕获;对变速风力机的静态性能研究建模方法是正确可行的。     

基于多时间尺度的并网型风力发电机组模型

对采用异步发电机与电网直接相连的风力发电机组进行了建模,并利用多时间尺度系统理论对模型进行了简化,采用仿真方法验证了简化后的模型的有效性。此外,还对整个风力发电系统的运行方式,补偿电容的动态作用进行了详细的分析,说明了此种风电机组的优缺点。     

基于混杂自动机的大型风力发电机组全程控制

风力发电系统是具有不确定性的复杂非线性系统,机组运行工况变化十分频繁。通过对风力发电机组的系统特性分析,发现风力发电系统呈现出混杂系统的典型特征。因此,基于混杂自动机理论建立了1.5 MW双馈型风电机组的混杂动态模型,并根据风力发电机组控制策略设计了能够在机组运行中实现全程自动化的混杂控制系统。仿真结果表明,基于混杂自动机的动态模型可以实现风电机组的全程模拟,所设计的混杂控制系统能够满足风电机组全程控制要求,证明了混杂系统理论应用于风力发电研究领域的有效性。     

基于混杂系统的风力发电机组建模与控制

针对风力发电机组系统固有的混杂系统典型特征,运用混杂自动机理论和混合逻辑动态理论建立了风力发电机组的混杂模型,设计了基于自动机模型的全程混杂控制系统,并以1台额定功率为300 MW的变速变桨距风力发电机组为例进行了仿真.结果表明:自动机模型可实现风电机组的全程模拟,自动机的混杂控制系统可满足风电机组全程控制的要求,而且基于混合逻辑动态模型的预测控制也实现了功率输出优化,证明了混杂系统理论应用于风力发电研究领域的有效性和实用性.     

变速恒频风力发电机组动态模型及并网研究

分析了风力发电系统的特点,着重介绍了变速恒频（Variable Speed Constant Frequency,VSCF）风力发电机组运行的基本原理．在此基础上,探讨了风力发电机组各部分的仿真建模,并分析了目前适用于不同条件下的双馈感应式异步发电机（Double—Fed Induction Generator,DFIG）变速恒频（AC—Exited Variable Speed Constant Frequency,AEVSCF）风力发电机的数学模型。对含变速恒频风机电网系统的故障扰动过程进行仿真分析．结果验证了建模的正确性。在故障扰动的最后对未来风电机组建模的研究重点提出了一些建议。     

消防安全保护系统在风力发电机组中的应用

风力发电近年来获得迅猛发展,风力发电机组消防安全问题也日益突出。分析了风力发电机组发生火灾的特性,在查阅国内外相关标准的基础上,总结了国内外有关风力发电机组消防技术的发展情况,指出开发设计更为完备的风力发电机组消防安全保护系统的必要性,提出综合消防保护系统设计方案,并对未来投入运营提出展望。     

液压型风力发电机组最优功率追踪控制方法研究

为研究风力发电机组风能利用率,对液压型风力发电机组的风力机特性和液压主传动闭式系统进行建模分析,提出一种变步长的最优功率追踪控制方法.该方法根据风力机角速度和发电功率判断风力机运行区间,依据不同的运行区间对给定功率进行实时调整,通过控制发电功率间接控制风力机角速度,实现最优功率追踪控制.基于30kVA液压型风力发电机组实验平台进行仿真和实验研究.结果表明:采用变步长最优功率追踪控制方法,系统压力和发电功率可准确地跟踪风速变化,该方法具有良好的控制效果.     

Adequacy assessment of generating systems containing wind power considering wind speed correlation

Wind power is an important renewable energy resource. Electrical power generation from wind energy behaves quite differently from that of conventional sources, and maintaining a reliable power supply is an important issue in power systems containing wind energy. In these systems, the wind speeds at different wind sites are correlated to some degree if the distances between the sites are not very large. Genetic algorithm methods are applied here to adjust autoregressive moving-average time series models in order to simulate correlated hourly wind speeds with specified wind speed cross-correlation coefficients of two wind sites. Multi-state wind energy conversion system models are used to incorporate the correlated wind farms in reliability studies of generating systems. A method to generate random numbers with specified correlation coefficients for application in a state-sampling Monte Carlo simulation technique is introduced. It is shown that the proposed method can be used in the adequacy assessment of a generating system incorporating partially dependent wind farms.     

Multistate Wind Energy Conversion System Models for Adequacy Assessment of Generating Systems Incorporating Wind Energy

Wind energy is considered to be a very promising alternative for power generation because of its tremendous environmental, social, and economic benefits. Electrical power generation from wind energy behaves quite differently from that of conventional sources. The fundamentally different operating characteristics of those facilities, therefore, affect the power system reliability in a manner different from that of the conventional systems. This paper is focused on the development of suitable models for wind energy conversion systems, in adequacy assessments of generating systems, using wind energy. These analytical models can be used in the conventional generating system adequacy assessment utilizing analytical or Monte Carlo state-sampling techniques. This paper shows that a five-state wind energy conversion system model can be used to provide a reasonable assessment of the practical power system adequacy studies, using an analytical method, or a state-sampling simulation approach.     

太阳能等效转化利用模型及其效益研究

以能源局域网为依托,研究太阳能在转化利用过程中不同“能质”能量之间的等效转化关系及其效益模型。综合考虑负荷需求特性及当前能源消费价格因素对太阳能利用方式的影响,以太阳能利用率最大和系统运行综合效益最大化为目标,构建太阳能转化利用多目标优化模型;然后,采用量子行为的粒子群优化算法对模型进行优化求解,并与传统单一供能模式进行对比分析。结果表明,所提模型能有效提高能耗系统对太阳能的综合利用率及消纳能力,并取得更高的能售效益。验证了所提模型及其运行方式的有效性和可行性,为大规模太阳能的开发和利用提供了一个新的思路。     

A sequential simulation technique for adequacy evaluation ofgenerating systems including wind energy

A wind energy conversion system (WECS) has a different impact on the reliability performance of a generating system than does a conventional energy conversion system. This is due to the variation of wind speeds and the dependencies associated with the power output of each wind turbine generator (WTG) in a wind farm. In this paper, a sequential Monte Carlo simulation technique is proposed for adequacy evaluation of a generating system including WECS. The method is based on an hourly random simulation to mimic the operation of a generating system, taking into account the auto-correlation and fluctuating characteristics of wind speeds, the random failure of generating units and other recognized dependencies. The hourly wind speeds are simulated utilizing autoregressive and moving average time series models that are established based on the F-criterion. A small reliability test system designated as the RBTS is used to illustrate the proposed method     

A review of wind energy technologies

Energy is an essential ingredient of socio-economic development and economic growth. Renewable energy sources like wind energy is indigenous and can help in reducing the dependency on fossil fuels. Wind is the indirect form of solar energy and is always being replenished by the sun. Wind is caused by differential heating of the earth's surface by the sun. It has been estimated that roughly 10 million MW of energy are continuously available in the earth's wind. Wind energy provides a variable and environmental friendly option and national energy security at a time when decreasing global reserves of fossil fuels threatens the long-term sustainability of global economy. This paper reviews the wind resources assessment models, site selection models and aerodynamic models including wake effect. The different existing performance and reliability evaluation models, various problems related to wind turbine components (blade, gearbox, generator and transformer) and grid for wind energy system have been discussed. This paper also reviews different techniques and loads for design, control systems and economics of wind energy conversion system.     

Grid power quality with variable speed wind turbines

Grid connection of renewable energy sources is essential if they are to be effectively exploited, but grid connection brings problems of voltage fluctuation and harmonic distortion. In the paper, appropriate modeling and simulation techniques are discussed for studying the voltage fluctuation and harmonic distortion in a network to which variable speed wind turbines are connected. Case studies on a distribution network show that the voltage fluctuation and harmonic problems can he minimized with the proposed power electronics interface and control system while the wind energy conversion system captures the maximum power from the wind as wind speed varies. The studies have also demonstrated the ability of the advanced converter to assist the system voltage regulation     

Wind energy for the 1990s and beyond

Electrical power must be available to the consumer in any amount upon demand. Conventional methods of power generation, such as the burning of fossil fuels, hydroelectric plants, and nuclear power plants, have considerable shortcomings. Governmental regulations have increased in quantity and have raised the already rigid standards of producing electric power without further damage to the environment. Electrical power produced by wind energy conversion systems are undergoing extensive research and revitalization as a viable solution to clean air power generation. The basic challenge to scientists and engineers is to develop wind energy conversion systems that produce adequate amounts of power, but at a cost comparable to present conventional methods. This article discusses the background and impact of the modern wind energy conversion system on future power generation.     

Application of Bayesian model averaging in modeling long-term wind speed distributions

Accurate estimation of wind speed distribution is critical to the assessment of wind energy potential, the site selection of wind farms, and the operations management of wind power conversion systems. This paper proposes a new approach for deriving more reliable and robust wind speed distributions than conventional statistical modeling approach. This approach combines Bayesian model averaging (BMA) and Markov Chain Monte Carlo (MCMC) sampling methods. The derived BMA probability density function (PDF) of the wind speed is an average of the model PDFs included in the model space weighted by their posterior probabilities over the sample data. MCMC method provides an effective way for numerically computing marginal likelihoods, which are essential for obtaining the posterior model probabilities. The approach is applied to multiple sites with high wind power potential in North Dakota. The wind speed data at these sites are the mean hourly wind speeds collected over two years. It is demonstrated that indeed none of the conventional statistical models such as Weibull distribution are universally plausible for all the sites. However, the BMA approach can provide comparative reliability and robustness in describing the long-term wind speed distributions for all sites, while making the traditional model comparison based on goodness-of-fit statistics unnecessary.     

A review on development of offshore wind energy conversion system

Wind energy conversion system, aiming to convert mechanical energy of air flow into electrical energy has been widely concerned in recent decades. According to the installation sites, the wind energy conversion system can be divided into land-based wind conversion system and offshore wind energy conversion (OWEC) system. Compared to land-based wind energy technology, although OWEC started later, it has attracted more attentions due to its significant advantages in sufficient wind energy, low wind shear, high power output and low land occupancy rate. In this paper, the principle of wind energy conversion and the development status of offshore wind power in the world are briefly introduced at first. And then, the advantages and disadvantages of several offshore wind energy device (OWED), such as horizontal axis OWED, vertical axis OWED and cross axis OWED are compared. Subsequently, several major constraints, such as complex marine environment, deep-sea power transmission and expensive cost of equipment installation faced by offshore wind conversion technology are presented and comprehensively analysed. Finally, based on the summary and analysis of some emerging technologies and the current situation of offshore wind energy utilization, the development trend of offshore wind power is envisioned. In the future, it is expected to witness multi-energy complementary, key component optimization and intelligent control strategy for smooth energy generation of offshore wind power systems.