风力发电机毕业论文英文文献翻译

附录一英文文献

Wind Energy Introduction

1.1 Historical Development

Windmills have been used for at least 3000 years, mainly for grinding grain or pumping water, while in sailing ships the wind has been an essential source of power for even longer. From as early as the thirteenth century, horizontal-axis windmills were an integral part of the rural economy and only fell into disuse with the advent of cheap fossil-fuelled engines and then the spread of rural electrification.The use of windmills (or wind turbines) to generate electricity can be traced back to the late nineteenth century with the 12 kW DC windmill generator constructed by Brush in the USA and the research undertaken by LaCour in Denmark. However, for much of the twentieth century there was little interest in using wind energy other than for battery charging for remote dwellings and these low-power systems were quickly replaced once access to the electricity grid became available. One notable exception was the 1250 kW Smith–Putnam wind turbine constructed in the USA in 1941. This remarkable machine had a steel rotor 53 m in diameter, full-span pitch control and flapping blades to reduce loads. Although a blade spar failed catastrophically in 1945, it remained the largest wind turbine constructed for some 40 years (Putnam, 1948).

Golding (1955) and Shepherd and Divone in Spera (1994) provide a fascinating history of early wind turbine development. They record the 100 kW 30 m diameter Balaclava wind turbine in the then USSR in 1931 and the Andrea Enfield 100 kW 24 m diameter pneumatic design constructed in the UK in the early 1950s. In this turbine hollow blades, open at the tip, were used to draw air up through the tower where another turbine drove the generator. In Denmark the 200 kW 24 m diameter Gedser machine was built in 1956 while Electricite′de France tested a 1.1 MW 35 m diameter turbine in 1963. In Germany, Professor Hutter constructed a number of innovative, lightweight turbines in the 1950s and 1960s. In spite of these technical advances and the enthusiasm, among others, of Golding at the Electrical Research Association in the UK there was little sustained interest in wind generation until the price of oil rose dramatically in 1973.

The sudden increase in the price of oil stimulated a number of substantial Government-funded programmes of research, development and demonstration. In the USA this led to the construction of a series of prototype turbines starting with the 38 m diameter 100 kW Mod-0 in 1975 and culminating in the 97.5 m diameter 2.5 MW Mod-5B in 1987. Similar programmes were pursued in the UK, Germany and Sweden. There was considerable uncertainty as to which architecture might prove most cost-effective and several innovative concepts were investigated at full scale. In Canada, a 4 MW vertical-axis Darrieus wind turbine was constructed and this concept was also investigated in the 34 m diameter Sandia Vertical Axis Test Facility in the

USA. In the UK, an alternative vertical-axis design using straight blades to give an ‘H’ type rotor w as proposed by Dr Peter Musgrove and a 500 kW prototype constructed. In 1981 an innovative horizontal-axis 3 MW wind turbine was built and tested in the USA. This used hydraulic transmission and, as an alternative to a yaw drive, the entire structure was orientated into the wind. The best choice for the number of blades remained unclear for some while and large turbines were constructed with one, two or three blades.

Much important scientific and engineering information was gained from these Government-funded research programmes and the prototypes generally worked as

designed. However, it has to be recognized that the problems of operating very large Figure 1.1 1.5 MW, 64 m diameter Wind Turbine (Reproduced by permission of NEG MICON)

wind turbines, unmanned and in difficult wind climates were often under-estimated and the reliability of the prototypes was not good. At the same time as the multi-megawatt prototypes were being constructed private companies, often with considerable state support, were constructing much smaller, often simpler,turbines for

commercial sale. In particular the financial support mechanisms in California in the mid-1980s resulted in the installation of a very large number of quite small(<100 kW) wind turbines. A number of these designs also suffered from various problems but, being smaller, they were in general easier to repair and modify. The so-called 'Danish' wind turbine concept emerged of a three-bladed,stall-regulated rotor and a fixed-speed, induction machine drive train. This decep-tively simple architecture has proved to be remarkably successful and has now been implemented on turbines as large as 60 m in diameter and at ratings of 1.5 MW. The machines of Figures 1.1 and 1.2 are examples of this design. However, as the sizes of commercially available turbines now approach that of the large prototypes of the 1980s it is interesting to see that the concepts investigated then of variable-speed operation, full-span control of the blades, and advanced materials are being used increasingly by designers. Figure 1.3 shows a wind farm of direct-drive, variable-speed wind turbines. In this design, the synchronous generator is coupled directly to the aerodynamic rotor so eliminating the requirement for a gearbox. Figure 1.4 shows a more conventional, variable-speed wind turbine that uses a gearbox, while a small wind farm of pitch-regulated wind turbines, where full-span control of the blades is used to regulate power, is shown in

Figure 1.5.

Figure 1.2 750 kW, 48 m diameter Wind Turbine, Denmark (Reproduced by permission of NEG MICON)

Figure 1.3 Wind Farm of Variable-Speed Wind Turbines in Complex Terrain (Reproduced by permission of Wind Prospect Ltd)

Figure 1.4 1 MW Wind Turbine in Northern Ireland (Reproduced by permission of Renew-able Energy Systems Ltd)

The stimulus for the development of wind energy in 1973 was the price of oil and concern over limited fossil-fuel resources. Now, of course, the main driver for use of wind turbines to generate electrical power is the very low C错误！未找到引用源。emissions (over the entire life cycle of manufacture, installation, operation and de-commissioning)

Figure 1.5 Wind Farm of Six Pitch-regulated Wind Turbines in Flat Terrain

(Reproduced by permission of Wind Prospect Ltd)

and the potential of wind energy to help limit climate change. In 1997 the Commis-sion of the European Union published its White Paper (CEU, 1997) calling for 12 percent of the gross energy demand of the European Union to be contributed from renewables by 2010. Wind energy was identified as having a key role to play in the supply of renewable energy with an increase in installed wind turbine capacity from 2.5 GW in 1995 to 40 GW by 2010. This target is likely to be achievable since at the time of writing, January 2001, there was some 12 GW of installed wind-turbine capacity in Europe, 2.5 GW of which was constructed in 2000 compared with only 300 MW in 1993. The average annual growth rate of the installation of wind turbines in Europe from 1993-9 was approximately 40 percent (Zervos, 2000). The distribution of wind-turbine capacity is interesting with, in 2000, Germany account- ing for some 45 percent of the European total, and Denmark and Spain each having approximately 18 percent. There is some 2.5 GW of capacity installed in the USA of which 65 percent is in California although with increasing interest in Texas and some states of the midwest. Many of the California wind farms were originally

constructed in the 1980s and are now being re-equipped with larger modern wind turbines.

Table 1.1 shows the installed wind-power capacity worldwide in January 2001 although it is obvious that with such a rapid growth in some countries data of this kind become out of date very quickly.

The reasons development of wind energy in some countries is flourishing while in others it is not fulfilling the potential that might be anticipated from a simple consideration of the wind resource, are complex. Important factors include the financial-support mechanisms for wind-generated electricity, the process by which the local planning authorities give permission for the construction of wind farms,and the perception of the general population particularly with respect to visual impact. In order to overcome the concerns of the rural population over the environ-mental impact of wind farms there is now increasing interest in the development of sites offshore.

1.2 Modern Wind Turbines

The power output, P, from a wind turbine is liven by the well-known expression:

P=错误！未找到引用源。

where ρ is the density of air (1.225 kg/错误！未找到引用源。), 错误！未找到引用源。is the power coefficient, A is the rotor swept area, and U is the wind speed.

The density of air is rather low, 800 times less than that of water which powers hydro plant, and this leads directly to the large size of a wind turbine. Depending on the design wind speed chosen, a 1.5 MW wind turbine may have a rotor that is more than 60 m in diameter. The power coefficient describes that fraction of the power in the wind that may be converted by the turbine into mechanical work. It has a theoretical maximum value of 0.593 (the Betz limit) and rather lower peak values are

achieved in practice (see Chapter 3). The power coefficient of a rotor varies with the tip speed ratio (the ratio of rotor tip speed to free wind speed) and is only a maximum for a unique tip speed ratio. Incremental improvements in the power coefficient are continually being sought by detailed design changes of the rotor and, by operating at variable speed, it is possible to maintain the maximum power coefficient over a range of wind speeds. However, these measures will give only a modest increase in the power output. Major increases in the output power can only be achieved by increasing the swept area of the rotor or by locating the wind turbines on sites with higher wind speeds.

Hence over the last 10 years there has been a continuous increase in the rotor diameter of commercially available wind turbines from around 30 m to more than 60 m. A doubling of the rotor diameter leads to a four-times increase in power output. The influence of the wind speed is, of course, more pronounced with a doubling of wind speed leading to an eight-fold increase in power. Thus there have been considerable efforts to ensure that wind farms are developed in areas of the highest wind speeds and the turbines optimally located within wind farms. In certain countries very high towers are being used (more than 60-80 m) to take advantage of the increase of wind speed with height.

In the past a number of studies were undertaken to determine the 'optimum size of a wind turbine by balancing the complete costs of manufacture, installation and operation of various sizes of wind turbines against the revenue generated (Mollyet al. 1993). The results indicated a minimum cost of energy would be obtained with wind turbine diameters in the range of 35-60 m, depending on the assumptions made. However, these estimates would now appear to be rather low and there is no obvious point at which rotor diameters, and hence output power, will be limited particularly for offshore wind turbines.

All modern electricity-generating wind turbines use the lift force derived from the blades to drive the rotor. A high rotational speed of the rotor is desirable in order to reduce the gearbox ratio required and this leads to low solidity rotors (the ratio of blade area/rotor swept area). The low solidity rotor acts as an effective energy concentrator and as a result the energy recovery period of a wind turbine, on a good site, is less than 1 year, i.e., the energy used to manufacture and install the wind turbine is recovered within its first year of operation (Musgrove in Freris, 1990).

附录二英文翻译

风能介绍

1.1发展历史

风车的使用至少已有三千年，主要用于磨粒或泵站水，而在帆船风已成为不可缺少的电力来源甚至更长的一段时间。从早在13世纪，水平轴风力发电的一个组成部分是农村经济，只有随着廉价的矿物燃料的引擎落入废弃，农村电气化才蔓延出来。利用风力发电（或风力发电机）发电可以追溯到十九世纪末期的12千瓦直流风力发电机，建造在美国的丹麦LaCour研究所。然而，20世纪大部分时期人们对使用风能没有兴趣，除了用于偏远住宅电力供应，并且一旦并入电网成为可能，这些低功耗系统很快就被取代。一个突出的例子是1941年史密斯普特南在美国建造的1250千瓦的风力发电机组，这台机组刚性转子直径是53米，充分跨度间距控制和扑叶片，以减少负载。虽然这种叶片风机在1945年失败了，但是它仍然是最大的风机在之后的约40年间。

Golding (1955年),Shepherd和Divone在Spera （1994 ）提供了一个令人着迷的早期风力发电机的发展史。1931年他们记录了100千瓦30米直径的苏联巴拉克拉风力发电机组和1950年代初英国Andrea Enfield 100千瓦24米直径风力发电机组的气动设计建造。在这空心涡轮叶片，展开着，被用来吸收空气动能透过机身推动另一端的发电机，1956年在丹麦生产出了200千瓦24米直径Gedser 机型，而后，在1963年法国的一家电力公司已完成了1.1兆瓦35米直径风力发电机的测试。五十年代和六十年代，德国的Hutter教授有了一些轻型涡轮机的创新。尽管有这些技术进步和研究热情，等等，但是Golding在英国的电气研究协会对风力机很少有持续的兴趣直到1973年石油价格显著上升时。

突然增加的石油价格刺激了一些实质性的政府资助方案的研究, 开发和示范。1975年，这直接导致美国设计了以100千瓦38米直径0型风机为开始的一系列风机模型，并且最终在1987年设计出2.5兆瓦97.5米直径5B的风力机模型。类似的方案同样在英国，德国和瑞典受到热捧。由于这些设计在最符合成本效益和一些创新的概念方面可能会有不确定性，因此，需要对其进行充分规模的调查。在加拿大，生产出了一台4兆瓦垂直轴Darrieus型风力机，并且这种概念也在美国和英国的34米直径Sandia垂直轴试验设备中进行测试，Peter Musgrove 博士提出使用直叶片做出的H型转子替代垂直轴的设计建造了一个500千瓦的样机。1981年美国的一台创新型3兆瓦水平轴的风力发电机组被生产出来并进行了测试。它使用液压传动以用来替代偏航驱动器，使整个结构导向对风。叶片数量最好的选择在某些方面仍然不是很明确，基本上大的风机都是使用单叶片，双叶片或者是三叶片。

许多重要的科学和工程信息都是从这些政府资助的研究方案和一般的原型设计工作中获得的。但是，必须认识到运行一个没有人工操作，大型的风力机的问题，这种恶劣的风气候经常是不可估计的，并且设备的可靠性不是很好。同时，多兆瓦的风机也在私人的公司中建造，往往相当多的国家支持，建设要小得多，往往很简单的风力机作为商业销售。20世纪80年代中期在加利福尼亚州，特别

是财政支持机制催生了大量小型（100千瓦）风力发电机的安装。其中的一些设计也有遇到了各种各样的问题，但是由于是小型的，可以利用普通简便的方法来修理和改进，所谓的Danish风力机概念出现了三叶片，失速调节转子和一个恒定的速率，感应电机驱动。这个简单的架构已被证明是非常成功的，并且有现在60米直径风力机一样大的直径和1.5兆瓦的功率。图1.1和图1.2这种设计的两个例子。然而，随着商用风力机的规模引用20世纪80年代的大型模型成为可能，有趣的是看到当时变速操作的概念调查，充分跨度控制叶片和增强的材料越来越多的被设计者使用到。图1.3显示了一个采用变速直趋的风力机的风场。在

图1.1 1.5兆瓦，64米直径风力机

这种设计中，同步发电机是直接耦合的气动转子，所以这样的就不需要齿轮变速箱了，图1.4显示了一个更传统，使用变速齿轮箱的变速风力机，而一个小风电场的音高调节风力发电机，叶片充分跨度控制是用来限制功率的，如图1.5。

图1.2 750千瓦，48米直径风力机

图1.3 在复杂地形上的变速调节风力发电场

图1.4 北爱尔兰1兆瓦风力发电机

刺激风力发电发展的是1973年的石油价格和对有限的化石燃料资源的关注，利用风力发电机发电的主要驱动力量是非常低的二氧化碳排放量（在制造，安装，操作和去调试的整个生命周期）和用来帮助限制气候变化影响的风能的潜力。1997年，欧洲联盟委员会出版了名为欧盟成员国在2010年12%的能源需求将从可再生能源中获得的白皮书。随着从1995年已安装的容量为2.5万千瓦的风力发电机组到2010年的40万千瓦这样的增长，风力发电已被确定为在可再生能源供应方面可发挥关键作用。这个目标是可能实现的，因为在2001年1月编写这个报告时，在欧洲已经有一些12万千瓦容量的风力发电机组的安装成为可能，从1993年只有300兆瓦和2000年的2.5万千瓦相比，这个目标将成为可能。从1993年9月开始欧洲安装风力发电机的年平均增长率约为40%，（Zervos,2000）。在欧洲风力发电机的能力分配是有趣的，2000年，德国约占欧洲总数的45%，丹麦和西班牙各占18%。还有约容量为250万千瓦的风力发电

机组安装在美国，其

图1.5

中65%是在加利福尼亚并且美国在德克萨斯州和一些中西部地区也表现出了越来越浓厚的兴趣，许多加利福尼亚的风力发电场是在80年代建造的，现在正在重新配备更大的现代化风力发电机。

表1.1显示了2001年1月世界范围内的装机容量，但是很显然，随着这样的增长速度，一些国家的这些数据将很快过时。

风能在一些国家能够蓬勃发展，而其他一些国家没有发挥它的潜力，可能是因为这些国家考虑到风能资源利用的复杂性。重要原因包括为风力发电提供的财政支持机制，地方规划局允许用于建造风力发电厂的过程和一般民众特别是在视觉上的看法的影响。为了克服村民对风力发电厂对环境的影响的关注，现在越来越关注风场的选址。

1.2 现代风力发电

风力发电机输出功率P由已知公式：

P=错误！未找到引用源。

ρ为空气密度（1.225kg/错误！未找到引用源。）,错误！未找到引用源。为功能效率，A为风轮面积，U为风速。

空气密度相当低，比水压小800倍，所以这就直接导致风力发电机需要大尺寸。取决于设计风速的选择，一台1.5兆瓦风力发电机可能会有60m直径的转子。功率描述为风能被转化成机械能的系数。它有一个理论最大值0.593（贝兹极限），而较低的峰值能够在实践中实现。风轮的功率系数随着速度比率峰值变化并且仅仅是一个最大的速度比率峰值。通过不断优化的详细设计和在变速情况下运行，风力机的风能利用系数得到不断改进，有可能在超出设计风速的同时保持最大风能利用系数。然而，这些措施将仅仅略有增加输出功率。为了达到增加输出功率的目的，主要靠增大风轮扫掠面积或者将风力发电机组安装在更大的风速区域。

过去十年到现在风力机风轮直径陆续有增加，从30m直径增加到超过60m 直径。风轮直径增大一倍就可以增大四倍的风能功率输出。当然，风速同样影响功率输出，双倍风速将更为突出的使风能功率输出增加8倍。因此，要充分考虑确保风电场建立在风速大的区域，并且风力发电机位于风场的最佳位置。在一些国家使用很高的塔架超过（60-80m）为了利用随着高度而增大的风速。

在过去的一些研究中，为了确定最佳的风力发电机大小以平衡全部的制造，安装成本和运行各尺寸风力发电机对生产的收益。根据已生产的风力机的假设，结果表明风力发电机叶轮直径在35-60米时能获得最低的能源成本。然而，这些假设将显现得相当低，并且风轮直径没有明显的数字，因此，风力机输出功率将是有限的，特别是海上风力发电机。

所有现代的风力发电机都使用来自叶片的升力来驱动风轮，高转速的转子是可取的，以减少所需的变速齿轮箱的增速比，并且这将降低密实比（叶片面积和风轮扫掠面积的比例）。低密实比风轮作为一种有效的风能利用机构，从一台风力发电机上的风能恢复周期，好的情况下少于一年，风能能够用于制造，并且风力发电机可在其第一年运作中恢复安装。