Generator speed regulation in the presence of structural modes through adaptive control using residual mode filters

Wind turbines operate in highly turbulent environments resulting in aerodynamic loads that can easily excite turbine structural modes, potentially causing component fatigue and failure. Two key technology drivers for turbine manufacturers are increasing turbine up time and reducing maintenance costs. Since the trend in wind turbine design is towards larger, more flexible turbines with lower frequency structural modes, manufacturers will want to develop control paradigms that properly account for the presence of these modes. Accurate models of the dynamic characteristics of new wind turbines are often not available due to the complexity and expense of the modeling task, making wind turbines ideally suited to adaptive control approaches. In this paper, we develop theory for adaptive control with rejection of disturbances in the presence of modes that inhibit the controller. A residual mode filter is introduced to accommodate these modes and restore important properties to the adaptively controlled plant. This theory is then applied to design an adaptive collective pitch controller for a high-fidelity simulation of a utility-scale, variable-speed wind turbine. The adaptive pitch controller is compared in simulations with a baseline classical proportional integrator (PI) collective pitch controller.     

风电叶片红外热波无损检测的实验探究

风电叶片是风电机组最关键的组件之一.随着风力发电机单台功率的不断提高,风轮叶片也越来越大,对质量可靠性要求也越来越高.但目前国内外尚无成熟的无损检测方法用于风电叶片检测.利用闪光灯脉冲激励红外无损检测方法对风电叶片制作过程中产生的几种典型缺陷进行了检测,取得了初步的实验结果.红外热波无损检测作为一种大面积、快速、非接触...     

风轮机雷达散射特性仿真及微多普勒特征分析

风轮机复杂的电磁散射特性,会对其附近的空管通信、导航和监视等电子设备产生严重影响.研究风轮机的电磁散射特性,可为风轮机杂波检测和抑制提供理论依据,对保证空中交通安全具有重要的意义.论文首先基于风轮机散射点叠加的理论,考虑了雷达入射波到风轮机叶片和桅杆的初始相位以及入射波方位角和俯仰角对回波的影响,将单基地回波模型扩展到双基地模型.同时,在散射点叠加模型的基础上,提出了基于混合模型的风轮机散射特性分析.混合模型结合了散射点叠加模型和电磁仿真软件FEKO的优点,考虑了电磁波在叶片和桅杆上的反射系数等因素对回波的影响,可以实现任意观测点处的电磁散射特性计算及其微多普勒特征的分析.最后,分别对散射点叠加模型、FEKO以及混合模型的风轮机电磁散射特性分析方法进行了对比分析,给出了各自的优缺点及其适用场合.     

An overview of the reliability prediction related aspects of high power IGBTs in wind power applications

Reliability is becoming more and more important as the size and number of installed Wind Turbines (WTs) increases. Very high reliability is especially important for offshore WTs because the maintenance and repair of such WTs in case of failures can be very expensive. WT manufacturers need to consider the reliability aspect when they design new power converters. By designing the power converter considering the reliability aspect the manufacturer can guarantee that the end product will ensure high availability. This paper represents an overview of the various aspects of reliability prediction of high power Insulated Gate Bipolar Transistors (IGBTs) in the context of wind power applications. At first the latest developments and future predictions about wind energy are briefly discussed. Next the dominant failure mechanisms of high power IGBTs are described and the most commonly used lifetime prediction models are reviewed. Also the concept of Accelerated Life Testing (ALT) is briefly reviewed.     

Beyond the harbour wall [offshore wind farm]

The Northumbrian port of Blyth is becoming established as a leading centre for wind energy development. During 1992, nine 300 kW wind turbines were installed along the harbour's east pier, to create the UK's first semi-offshore wind farm. This pioneering scheme has now been followed by the commissioning of the Blyth Offshore wind farm-a joint venture between Shell, Powergen Renewables, Nuon and Amec-comprising two 2 MW wind turbines located 1 km off the coast. Blyth Offshore represents the World's first multi-megawatt wind farm in serious seas. Blyth Harbour and Blyth Offshore were both developed by Hexham-based AMEC Border Wind. The period between these two projects has seen a dramatic increase in the size of wind turbines, represented by the jump from 300 kW to 2 MW, along with marked improvements in reliability allowing the maintenance interval to be increased from fortnightly to annually. These two factors, which significantly reduce installation and operating costs, combined with the difficulty in obtaining planning permission for onshore sites, have stimulated a growing interest in offshore schemes. The success of Blyth Offshore, along with specific governmental support for offshore wind power via the Renewables Obligation could lead to around six 50 MW wind farms in UK waters in the next few years. This paper discusses the technical aspects, design parameters, foundation design, the turbines, electrical infrastructure, installation and initial operation of the wind farm     

Reliability Assessment of Microgrid Using Sequential Monte Carlo Simulation

Sequential Monte Carlo simulation method is introduced to the reliability assessment of microgrid,and a Weibuil distribution wind speed model is built to simulate the hourly wind speed of a specific site.Wind turbine generator model combined with a two-state reliability model is applied to Monte Carlo simulation method,and results show that the wind turbine reliability model works well with sequential Monte Carlo simulation.A two-state reliability model of micro gas turbine and a load model from IEEE reliability test system(IEEE RTS)are also introduced to the reliability evaluation of microgrid.Case studies show that Monte Carlo simulation method is flexible and efficient dealing with microgrid consisting of renewable resources with fluctuation characteristics.     

Current Management Reliability Objectives

In summary, I will keynote this Symposium by expressing the following six points: 1) We accept the view which has been expressed by General Davis and others that reliability is a general management responsibility. 2) To enable general management to do their part effectively, reliability specialists must express their requests for support in terms of cost effectiveness. 3) Reliability is a branch of engineering technology that, like all other branches, must be supported by a research program. 4) After research has provided potentially effective reliability technology, the Program Plan for each project must be such as to ensure effective use of this technology. 5) A system of operations evaluation must be established to give immediate visibility to any deficiencies in compliance with or the results of reliability plans. 6) Our experience has shown the traditional practices of the aerospace industry are well suited to achieving reliability. It is important for customer contracting agencies to recognize that many of the practices which enable industry to create reliability have to be supported by overhead funds. Almost the entire Reliability Resources Development Program must be absorbed by our overhead budget. Also, it is important for these contracting agencies to recognize that reliability resources must be an important factor in ``Make' or ``Buy' decisions. For example, the Prime Contractor's resources include design assurance and quality assurance disciplines which may be lost when an item is transferred from the ``Make' to the ``Buy' category.     

Analysis of a variable-speed wind energy conversion scheme with doubly-fed induction generator

In the last decade, the high penetration of wind turbines into the power system has been closely related to the advancement of wind turbine technology and control. The electric system contained by a large wind turbine, as well as within an offshore wind farm with hundreds of MW power capacity, has become more and more important in the interaction between the mechanical system of the wind turbine and the main power system. Furthermore, power electronics is entering the wind turbine circuitry which improves the controllability. The work presented in this paper has the main objective of extending the ability of the existing wind turbine design tools, in order to simulate the dynamic behaviour of wind turbines and the wind turbine–grid interaction.     

风力发电机控制系统的可靠性设计

风力发电机控制系统作为风力发电机系统的核心,对于控制系统的可靠性研究是有很重要的现实意义。本文提出了风力发电机控制系统的可靠性设计,包括变桨系统、偏航控制、励磁系统、变流系统、雷电保护和冗余系统。本文将可靠性设计的方法应用到风力发电机控制系统的设计上,大大提高了机组的可靠性。     

A New Interconnecting Method for Wind Turbine/Generators in a Wind Farm and Basic Performances of the Integrated System

A new interconnecting method for a cluster of wind turbine/generators is proposed, and some examples of the basic characteristics of the integrated system are shown. This method can be achieved with a wind turbine generating system using a shaft generator system. A group of wind turbine/generators can be interconnected easily with the proposed method, and high reliability and electric output power with high quality are also expected. Moreover, since this method enables transmission of the generated power through a long-distance dc transmission line, the optimum site for wind turbines can be selected so as to acquire the maximum wind energy.      

基于集员未知输入观测器的风力机桨距执行器故障诊断

风力机一般放置在恶劣的环境中,其桨距执行器极易出现故障。文中针对一类含有未知但有界干扰和噪声的风力机系统的桨距执行器故障问题,设计了集员未知输入观测器对桨距的执行器故障进行检测并分离。采用气动机理和现代辨识原理建立风力机系统模型,通过优化未知输入观测器设计对系统中的干扰解耦,基于中心对称多胞体估计不考虑故障时残差的区间包络,并将其作为残差估计的上下动态阈值,实现状态估计。在上述基础上提出了利用一组集员未知输入观测器进行故障诊断的策略。仿真结果表明,在实验过程中,文中所设计的集员未知输入观测器准确地诊断出了风力机桨距执行器的3阶和5阶线性系统在发生突变故障和缓慢时变故障的时间和位置,证明了所提故障诊断策略的有效性。     

基于微多普勒特征的风轮机雷达杂波检测

作为一种清洁能源和可再生能源的形式,近年来风能受到了全球各国的普遍关注,风轮机会对其附近的航管监视雷达产生不利影响。风轮机雷达杂波检测技术的研究,对于保障民航飞机的空中交通安全起着重要作用。提出了一种基于风轮机雷达回波微多普勒特征的杂波检测方法,该方法利用风轮机与雷达波束不同位置条件下风轮机杂波的微动特征实现风轮机杂波的检测。对检测出的存在风轮机杂波的距离单元进一步判断是否存在飞机目标,进而只需对存在飞机目标的距离单元进行杂波抑制。仿真结果表明该算法能够实现风轮机雷达杂波的有效检测。      

光风能混合双动力智能小车设计说明

本文着重分析探讨研究微型风力-太阳能光伏互补发电系统.风能和太阳能具有天然互补性,因此风能与光伏混合双动力,给智能小车供电,可靠性高,同时合理的配置储能装置的容量,效率高.我们希望通过深入研究,为实现新能源综合利用提供一种研究思路与设计方法,以期能为以后的实际工作起到一定的借鉴作用.     

Robust and fault-tolerant linear parameter-varying control of wind turbines

High performance and reliability are required for wind turbines to be competitive within the energy market. To capture their nonlinear behavior, wind turbines are often modeled using parameter-varying models. In this paper we design and compare multiple linear parameter-varying (LPV) controllers, designed using a proposed method that allows the inclusion of both faults and uncertainties in the LPV controller design. We specifically consider a 4.8 MW, variable-speed, variable-pitch wind turbine model with a fault in the pitch system.We propose the design of a nominal controller (NC), handling the parameter variations along the nominal operating trajectory caused by nonlinear aerodynamics. To accommodate the fault in the pitch system, an active fault-tolerant controller (AFTC) and a passive fault-tolerant controller (PFTC) are designed. In addition to the nominal LPV controller, we also propose a robust controller (RC). This controller is able to take into account model uncertainties in the aerodynamic model.The controllers are based on output feedback and are scheduled on an estimated wind speed to manage the parameter-varying nature of the model. Furthermore, the AFTC relies on information from a fault diagnosis system.The optimization problems involved in designing the PFTC and RC are based on solving bilinear matrix inequalities (BMIs) instead of linear matrix inequalities (LMIs) due to unmeasured parameter variations. Consequently, they are more difficult to solve. The paper presents a procedure, where the BMIs are rewritten into two necessary LMI conditions, which are solved using a two-step procedure.Simulation results show the performance of the LPV controllers to be superior to that of a reference controller designed based on classical principles.     

Wind power development in Europe

More than 70% of the total worldwide electricity-generating wind turbines (17500 MW total) has been installed in Europe. Of these, 3500 MW were installed in 2000 alone, continuing an impressive pace of development over the last several years. At the same time, the European wind manufacturing industry is booming with two-thirds of the world market share. These developments are attributed to the effective support of the European Union and of the national European states, following their commitment to reduce greenhouse gas (GHG) emissions. Wind power is now seen as a clean, cost-effective alternative to other forms of conventional electricity production with clear benefits to the environment and to the economy, as a whole. In this review paper the current state and prospects of wind power in Europe are described, with special emphasis on the three countries leading wind power development in Europe, i.e., Germany, Denmark, and Spain. The investment models applied in Europe play a decisive role in this development. Their differences and effects are shown and the role of renewables in reducing CO₂ (the primary GHG) emissions is highlighted. Finally, current trends and prospects of the European Wind Turbine technology are discussed     

Kraftwerkseigenschaften von Windenergieanlagen hinsichtlich Kurzschlussverhalten, Engpass- und Blindleistungsmanagement sowie Spannungsregelung

The increasing number of wind turbines will lead to new demands for transmission and distribution system control in the years to come. In order to ensure a smooth integration of wind energy into an electrical energy system structure, wind farms will have to possess power plant properties and be able to provide ancillary services. The ENERCON concept offers solutions not only for critical situations, such as short-circuits and bottlenecks in the grid, but also for normal operation, such as reactive power management or voltage control. Wind farms will essentially function in a manner similar to conventional power plants and moreover offer additional advantages in the distribution grid.     

大型风力机的噪声源产生机制实验研究

近年来,风力发电在国内得到了快速发展,但大型风力机产生的噪声也引起了广泛关注。该文通过远场传声器测量法开展了大型风力机噪声实验,研究了风力机的主要噪声源位置及产生机制。结果表明,在风力机的来流风的下游方向、风力机风轮叶片平面方向的噪声较大,存在声压级峰值的纯音基频和倍频,表明风力机的主要噪声源是叶片尖端气动噪声和风轮后面的机械噪声。最后指出了对这些主要噪声源进行有效控制的一些措施。     

Computer Reliability Optimization System

The short electronic system development time, the acute competitiveness, the emphasis on lower costs, and the insistence upon high reliability has fostered practical computerization of the manager's and designer's reliability function. This computerization attempts to achieve feasible system optimization. The Computerized Reliability Optimization System (CROS) was developed by Hoffman Electronics Corporation's Computer-Aided-Design, Analysis, and Reliability Group to provide an optimum solution to the present system reliability methods. CROS is a comprehensive set of computer programs and a complementary design and management method for handling the total reliability function from proposal effort through the production and field-data analysis. The organization, application, feasibility, and results of CROS are discussed.     

中国风电并网问题综述

随着传统能源的减少,开发利用可再生能源、实现能源的可持续发展成为世界各国能源发展战略的重要举措。风能作为可再生能源的重要方向,得到快速发展,但是仍存在许多问题,风电机组的并网问题首当其冲。造成此问题的原因是多方面的,文中主要从当前中国风电的并网现状、风电机组并网技术分析、风电并网对电力系统的影响以及如何解决风电机组的并网问题等方面入手,对中国风电并网中出现的问题进行综合分析,以促进风电产业的健康快速发展。     

A Review of the State of the Art of Power Electronics for Wind Turbines

This paper reviews the power electronic applications for wind energy systems. Various wind turbine systems with different generators and power electronic converters are described, and different technical features are compared. The electrical topologies of wind farms with different wind turbines are summarized and the possible uses of power electronic converters with wind farms are shown. Finally, the possible methods of using the power electronic technology for improving wind turbine performance in power systems to meet the main grid connection requirements are discussed.