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兆瓦級風(fēng)力發(fā)電機(jī)控制系統(tǒng)設(shè)計(jì)——液壓系統(tǒng)(文獻(xiàn)翻譯) 3
一級標(biāo)題小二號黑體居中,段前0磅,段后12磅。
每一章另起頁
利用功率電子變頻器獲取最大的風(fēng)能策略
章節(jié)采用三級標(biāo)題,用阿拉伯?dāng)?shù)字連續(xù)編號,例如1,1.1,1.1.1。
二級標(biāo)題宋體四號,左對齊,段前距12磅,段后距0磅
1 緒論
地球氣候的運(yùn)作就像一個巨大的加熱引擎。世界各地的氣候變化都受到了它的影響。但巨大的加熱引擎卻是充足風(fēng)能的供應(yīng)者。按照美國能源部報(bào)道:世界上的風(fēng)能理論上能夠滿足超過15倍世界當(dāng)前能源的需求。
正文: 中文為小四號宋體,英文為Times New Roman,首行縮進(jìn)二個字,1.25倍行距。
1.1 變速風(fēng)力發(fā)電機(jī)系統(tǒng)的基本組成
典型的變速風(fēng)力發(fā)電系統(tǒng)如圖1-1-1所示。
圖1-1-1 典型變速風(fēng)力發(fā)電機(jī)組
許多商業(yè)用途的
通過對圖1-1-1的分析可知,圖中虛線方框處為功率電子變換器。在本文中功率電子變換器也被稱為逆變器。
1.2風(fēng)力機(jī)性能
如一臺風(fēng)力機(jī)風(fēng)輪的摩擦力被忽視的話,那么風(fēng)力機(jī)的動力表達(dá)式就為等式(1.2.1)至等式(1.2.4)。在等式(1.2.1)中,是風(fēng)力機(jī)風(fēng)輪的機(jī)械轉(zhuǎn)矩,
公式應(yīng)另起一行,正文中的公式、算式或方程式等應(yīng)編排序號,公式按章節(jié)順序編號。公式序號必須連續(xù),不得重復(fù)或跳缺。重復(fù)引用的公式不得另編新序號。
(1.2.1)
。等式(1.2.4)中的代表的含義是風(fēng)輪的最大旋轉(zhuǎn)半徑。而TSR最確切地含義是風(fēng)輪槳葉速度與風(fēng)速的比率。
圖1-2-1 垂直軸風(fēng)力機(jī)特征曲線
;圖名位于圖的正下方,用宋體小五號加粗;圖表按章編號,例如表2-7為第二章第七個表;圖3-1為第三章第1個圖。
1.3風(fēng)力發(fā)電機(jī)組及逆變器
三級標(biāo)題黑體小四號書寫
左對齊,段前距12磅,段后距0磅
1.5研究目的和方法
1.5.1目標(biāo)
本文的研究目的是通過對變速風(fēng)力發(fā)電系統(tǒng)的軟硬件的調(diào)查、策劃和實(shí)施來獲取最大的能源策略。
的建模和仿真結(jié)果,且論證了逆變器布局創(chuàng)新的優(yōu)勢。在文中提及了我們研究小組建立的風(fēng)機(jī)仿真系統(tǒng)用于論證最大能量獲取算法的方法。
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2 最大風(fēng)能獲取智能算法
2.1看法
2.1.1無風(fēng)速測量的獨(dú)立算法
風(fēng)力機(jī)理論說明當(dāng)尖速比保持在最佳值時風(fēng)力機(jī)的轉(zhuǎn)換效能才會最大。回顧第一章可知,尖速比控制方式的原理是直接監(jiān)測和控制尖速比值。然而對于尖速比值的測量難度很大。特別是基于尖速比控制策略的執(zhí)行相當(dāng)復(fù)雜。而功率信號回饋是一種無須測量尖速比就能獲取最大風(fēng)能的控制方式。這主要是由于功率信號回饋控制方式依賴于風(fēng)力機(jī)的特性。這就意味著在該控制初期和控制計(jì)劃期間都要實(shí)時的獲取風(fēng)力機(jī)的特性
圖2-1-1 最大功率算法信號流程圖
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英文文獻(xiàn)格式不限
Maximum Wind Energy Extraction Strategies Using Power Electronic Converters
Chapter 1 Introduction
The atmosphere of the Earth works like a huge heat engine. The air in tropical area arises and the air from the polar area fills its place. This huge heat engine is an abundant wind energy supplier. According to the U.S. Department of Energy, the world's winds could theoretically supply more than 15 times current world energy demand.
Compared to fossil fuel and nuclear electrical power generation, wind energy conversion has several notable advantages, including abundant supplies, renewable sources, environmental friendliness, and economical competitiveness, in addition to its widespread availability and relatively small land usage. As such an attractive means of alternative energy conversion, wind energy generation has a world-wide average growth rate of 31 % in the last 10 years. The cost of electricity from utility-scale wind systems has dropped by more than 80% over the last 20 years. In the early 1980's, wind-generated electricity cost was as much as 30 cents (US) per kilowatt-hour (kWh). Now, large wind power plants are generating electricity at costs as low as 4 cents (US) per kWh. As a result, Wind Power Generation Systems (WPGS) have been developing rapidly in recent years all over the world. Research work on WPGS is also receiving more and more attentions.
.
1.1 Basic VSWT System Configuration
Figure1-1-1 shows a typical VSWT energy generation system. Various wind turbines from a hundred watts power level to mega watts power level have been used in WPGSs, such as horizontal axis wind turbines with different numbers of blades, vertical axis wind turbines which are also named as Darrieus Turbines, and other innovative turbines like Savonius wind turbine [1]. Horizontal Axis Wind Turbine is the most popular type.
Many commercial WPGSs adopt high speed induction or synchronous generators coupled to the wind turbines through gearboxes. In recent years, low speed synchronous generators, which are directly coupled to wind turbines without gear boxes, are gaining popularity. This structure benefits the WPGS in eliminating the gear box maintenance, reducing the noise and lowering the cost.
Inside the inverter, the variable-frequency variable-voltage electricity from the generator is first converted from AC to DC through a rectifier. Both controlled or uncontrolled rectifiers may be adopted. An uncontrolled rectifier has the benefit of simplicity, while a controlled rectifier is able to contain the dc-link voltage within the inverter's operational voltage range during high wind speed situations.
1.2 Wind Turbine Characteristic
If the rotor friction of a wind turbine is ignored, the dynamics of the turbine can be simply expressed using Equations (1.2.1) to (1.2.4)[1]. In Equation (1.2.1),is the turbine rotor's mechanical torque,is the load torque,is the turbine rotor's moment of inertia, andis the turbine rotor's angular speed. Equation (1.2.2) is derived from Equation (1.2.1) multiplied by, whereand are the turbine's mechanical power and the load power respectively.
(1.2.1)
Chapter 2 Intelligent Maximum Wind Power Extraction Algorithm
2.1 Overview
2.1.1 An Independent Algorithm without Wind Speed Measurements
Wind turbine theory reveals that a maximum turbine energy conversion efficiency occurs when the Tip-Speed Ratio (TSR) is kept at its optimal value. As reviewed in Chapter 1,the principle of TSR Control method is to directly detect and control the TSR value. However, due to the difficulties of TSR measurement, a control strategy based on the tip-speed ratio is practically difficult to implement. Power Signal Feedback (PSF) control method was then proposed to extract maximum wind power without measuring the TSR. Basically PSF Control method is dependent of the characteristics of a wind turbine, which means the turbine characteristics have to be obtained either before or during the execution of the control scheme.
2.1.2 The Algorithm Existence Analysis
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