3668 小型風(fēng)力發(fā)電機(jī)總體結(jié)構(gòu)的設(shè)計

3668 小型風(fēng)力發(fā)電機(jī)總體結(jié)構(gòu)的設(shè)計,小型,風(fēng)力發(fā)電機(jī),總體,整體,結(jié)構(gòu),設(shè)計 摘要I摘要基于開發(fā)風(fēng)能資源在改善能源結(jié)構(gòu)中的重要意義，本論文對風(fēng)力機(jī)的特性作了簡要的介紹，且對風(fēng)力機(jī)的各種參數(shù)和風(fēng)力機(jī)類型作了必要的說明。在此基礎(chǔ)上，對風(fēng)力發(fā)電機(jī)的原理和結(jié)構(gòu)作了細(xì)致的分析。首先，對風(fēng)力發(fā)電機(jī)的總體機(jī)械結(jié)構(gòu)進(jìn)行了設(shè)計，并且設(shè)計了限速控制系統(tǒng)。本課題設(shè)計的是一種新型的立式垂直軸小型風(fēng)力發(fā)電機(jī)，由風(fēng)機(jī)葉輪、立柱、橫梁、變速機(jī)構(gòu)、離合裝置和發(fā)電機(jī)組成。這種發(fā)電機(jī)有體積小、噪音小、使用壽命長、價格低的特點，適合在有風(fēng)能資源地區(qū)的樓房頂部，供應(yīng)家庭用電，例如照明：燈泡,節(jié)能燈；家用電器:電視機(jī)、收音機(jī)、電風(fēng)扇、洗衣機(jī)、電冰箱。其次，在老師的幫助下制作了限速控制的模型。通過模型驗證了小型垂直式風(fēng)力發(fā)電機(jī)限速控制系統(tǒng)總體方案在實踐中的效果，并且驗證了程序是否正確，以及電路的設(shè)計是否合理。最后，模型驗證的結(jié)果表明我設(shè)計的限速控制系統(tǒng)方案可行，程序正確，電路設(shè)計合理。為該類型風(fēng)力發(fā)電機(jī)的設(shè)計和商品生產(chǎn)提供了理論依據(jù)。關(guān)鍵詞：風(fēng)力發(fā)電；限速控制系統(tǒng)；小型風(fēng)力發(fā)電機(jī)；小型垂直軸風(fēng)力發(fā)電機(jī)。摘要IIAbstractExploiting wind energy resources is of great significance in improving energy structure. In the discourse，the characters of wind generator are introduced briefly，while parameters and types of wind generators are also narrated. Base on these， the theory and constitution of the wind generator are meticulously analyzed. Firstly，Has carried on the design to wind-driven generator's overall mechanism, And has designed the regulating control system. What I design is one kind of new vertical axis small wind-driven generator, by the air blower impeller, the column, the crossbeam, the gearshift mechanism, the engaging and disengaging gear and the generator is composed. This kind of generator has the volume to be small, the noise is small, the service life is long, the price low characteristic, suits in has the wind energy resources area building crown, the supply family uses electricity, For example illumination: The light bulb, conserves energy the lamp; Domestic electric appliances: Television, radio, electric fan, washer, electric refrigerator.Secondly，I have manufactured the regulating control model. Through model verification small perpendicular wind-driven generator regulating control system overall concept effect in reality, and has confirmed the procedure to be whether correct, as well as electric circuit's design to be whether reasonable.Finally，Model verification's result indicated I design the regulating control system plan is feasible, the procedure is correct, the circuit design is reasonable. It provides according as theory for qualitative design and commercial manufacture of this type of wind generator.Key words：Wind power generation；Regulating control system；Small wind-driven generator；Small vertical axis wind-driven generator.目錄III目錄摘要 ....................................................................ⅠABSTRACT ...............................................................Ⅱ第一章 概述 ...........................................................11.1 風(fēng)力發(fā)電機(jī)概況 ....................................................11.2 風(fēng)力發(fā)電機(jī)的研究現(xiàn)狀 ............................................11.2.1 國外風(fēng)力發(fā)電機(jī)的研制情況 .....................................11.2.2 國內(nèi)風(fēng)力發(fā)電機(jī)的研制情況 ....................................21.3 研究風(fēng)力發(fā)電機(jī)的目的和意義 .......................................41.4 我國的風(fēng)能資源及其分布 ...........................................5第二章 風(fēng)力機(jī)理論 ....................................................82.1 基本公式 ........................................................82.1.1 風(fēng)能利用系數(shù) ................................................82.1.2 風(fēng)壓強(qiáng) ......................................................82.1.3 阻力式風(fēng)力機(jī)的最大效率 ......................................82.2 工作風(fēng)速與輸出功率 ..............................................92.2.1 風(fēng)力發(fā)電機(jī)的輸出效率 .........................................92.2.2 工作風(fēng)速與輸出功率 ............................................92.2.3 啟動風(fēng)速和額定風(fēng)速的選定 .....................................102.3 風(fēng)能利用與氣象 ..................................................122.3.1 風(fēng)的觀測對風(fēng)能利用的意義 .....................................122.3.2 風(fēng)能利用中需要的氣象調(diào)查 .....................................132.4 風(fēng)的觀測 ........................................................13第三章 風(fēng)力發(fā)電機(jī)方案和結(jié)構(gòu)設(shè)計 ....................................143.1 小型垂直式風(fēng)力發(fā)電機(jī)方案設(shè)計 ....................................143.2 風(fēng)葉 ............................................................143.3 行星齒輪加速器設(shè)計計算 ..........................................143.3.1 設(shè)計要求 .....................................................153.3.2 選加速器類型 .................................................163.3.3 確定行星輪數(shù)和齒數(shù) ............................................163.3.4 壓力角( )的選擇 ..............................................16?3.3.5 齒寬系數(shù)的選擇 ................................................173.3.6 模數(shù)選擇 ......................................................173.3.7 預(yù)設(shè)嚙合角 ....................................................173.3.8 太陽輪與行星輪之間的傳動計算 ..................................173.3.9 行星輪與內(nèi)齒輪之間的傳動計算 ..................................183.3.10 行星排各零件轉(zhuǎn)速及扭矩的計算 ..................................183.3.11 行星排上各零件受力分析及計算 ..................................193.3.12 行星齒輪傳動的強(qiáng)度校核計算 ....................................203.4 電磁離合器設(shè)計計算 ...............................................243.4.1 選型 ..........................................................243.4.2 牙嵌式電磁離合器的動作特性 ....................................24目錄IV3.4.3 離合器的計算轉(zhuǎn)矩 ..............................................243.4.4 離合器的外徑 ..............................................243.4.5 離合器牙間的壓緊力 ...........................................243.4.6 線圈槽高度 ...................................................243.4.7 磁軛底部厚度 ................................................253.4.8 銜鐵厚度 ...................................................25第四章 限速控制系統(tǒng)方案設(shè)計 ..........................................264.1 設(shè)計限速控制系統(tǒng)的目的 ...........................................264.2 限速控制系統(tǒng)方案分析 .............................................264.3 單片機(jī) ............................................................264.4 信號采集 .........................................................264.5 電路 .............................................................264.6 限速控制程序 ...................................................274.6.1 定時器周期 ....................................................274.6.2 程序流程圖 ....................................................274.6.3 限速控制程序....................................................28第五章 控制系統(tǒng)總體分析 ..............................................30 5.1 實驗和模型設(shè)計的目的 ............................................305.2 模型設(shè)計 ........................................................305.2.1 設(shè)計技術(shù)指標(biāo) ................................................305.2.2 模型設(shè)計器件 ...................................................305.3 電路板 ..........................................................305.4 限速控制程序裝置 ................................................315.5 實驗?zāi)Ｐ徒Y(jié)果分析 ................................................32第六章 結(jié)束語 ....................................................33致謝 .....................................................................34參考文獻(xiàn) ..........................................................358Self-Excitation and Harmonics in Wind Power GenerationE. Muljadi ， C. P. ButterfieldNational Renewable Energy Laboratory, Golden, Colorado 80401H. RomanowitzOak Creek Energy Systems Inc.,Mojave, California 93501R. YingerSouthern California Edison,Rosemead, California 91770Traditional wind turbines are commonly equipped with induction generators because they are inexpensive, rugged, and require very little maintenance. Unfortunately, induction generators require reactive power from the grid to operate，capacitor compensation is often used. Because the level of required reactive power varies with the output power, the capacitor compensation must be adjusted as the output power varies. The interactions among the wind turbine, the power network, and the capacitor compensation are important aspects of wind generation that may result in self-excitation and higher harmonic content in the output current. This paper examines the factors that control these phenomena and gives some guidelines on how they can be controlled or eliminated.1．Introduction Many of today’s operating wind turbines have fixed speed induction generators that are very reliable, rugged, and low cost. During normal operation, an induction machine requires reactive power from the grid at all times. The most commonly used reactive power compensation is capacitor compensation. It is static, low cost. Different sizes of capacitors are generally needed for different levels of generation.Although reactive power compensation can be beneficial to the overall operation of wind turbines, we should be sure the compensation is the proper size and provides proper control. Two important aspects of capacitor compensation, self-excitation and harmonics ,are the subjects of this paper.2．Power System Network Description A diagram representing this system is shown in Fig(1). The power system components analyzed include the following:? An infinite bus and a long line connecting the wind turbine to the substation? A transformer at the pad mount? Capacitors connected in the low voltage side of the transformer? An induction generator9For the self-excitation, we focus on the turbine and the capacitor compensation only the right half of Fig. For harmonic analysis, we consider the entire network shown in Fig.3. Self-Excitation3.1 The Nature of Self-Excitation in an Induction Generator. Self-excitation is a result of the interactions among the induction generator, capacitor compensation, electrical load, and magnetic saturation. This section investigates the self-excitation process in an off-grid induction generator, knowing the limits and the boundaries of self-excitation operation will help us to either utilize or to avoid self-excitation.Fixed capacitors are the most commonly used method of reactive power compensation in a fixed-speed wind turbine. An induction generator alone cannot generate its own reactive power; it requires reactive power from the grid to operate normally, and the grid dictates the voltage and frequency of the induction generator.One potential problem arising from self-excitation is the safety aspect. Because the generator is still generating voltage, it may compromise the safety of the personnel inspecting or repairing the line or generator. Another potential problem is that the generator’s operating voltage and frequency may vary. Thus, if sensitive equipment is connected to the generator during self-excitation, that equipment may be damaged by over/under voltage and over/ under frequency operation. In spite of the disadvantages of operating the induction generator in self-excitation, some people use this mode for dynamic braking to help control the rotor speed during an emergency such as a grid loss 10condition. With the proper choice of capacitance and resistor load, self-excitation can be used to maintain the wind turbine at a safe operating speed during grid loss and mechanical brake malfunctions。3.2 Steady-State Representation. The steady-state analysis is important to understand the conditions required to sustain or to diminish self-excitation. As explained above, self-excitation can be a good thing or a bad thing, depending on how we encounter the situation. Figure 2 shows an equivalent circuit of a capacitor compensated induction generator. As mentioned above, self-excitation operation requires that the balance of both real and reactive power must be maintained. Equation （1）gives the total admittance of the system shown in Fig(2):+ + =0 （1）SY'M'Rwhere= effective admittance representing the stator winding, the capacitor, SYand the load seen by node M= effective admittance representing the magnetizing branch as seen by 'Mnode M,referred to the stator side= effective admittance representing the rotor winding as seen by node 'RM, referred to the stator sideEquation 1 can be expanded into the equations for imaginary and real parts as shown in Eqs.2and3:（2）Fig. 2 Per phase equivalent circuit of an induction generator under self-excitation mode11Fig.3 A typical magnetization characteristic= stator winding resistanceSR= stator winding leakage inductanceL= rotor winding resistance'= rotor winding leakage inductance'R= stator winding resistance'MS = operating slip= operating frequency?= load resistance connected to the terminalsLC = capacitor compensation=阻抗SR12One important aspect of self-excitation is the magnetizing characteristic of the induction generator. Figure 3 shows the relationship between the flux linkage and the magnetizing inductance for a typical generator; an increase in the flux linkage beyond a certain level reduces the effective magnetizing inductance . This graph can 'MLbe derived from the experimentally determined no-load characteristic of the induction generator. The voltage at the terminals of the induction generator presented in Fig . （5） shows the impact of changes in the capacitance and load resistance. As shown in Fig. （5）, the load resistance does not affect 13the terminal voltage, especially at the higher rpm （higher frequency）, but the capacitance has a significant impact on the voltage profile at the generator terminals. A larger capacitance yields less voltage variation with rotor speed, while a smaller capacitance yields m ore voltage variation with rotor speed. As shown in Fig. 6, for a given capacitance, changing the effective value of the load resistance can modulate the torque-speed characteristic.These concepts of self-excitation can be exploited to provide dynamic braking for a wind turbine mentioned above to prevent the turbine from running away when it loses its connection to the grid; one simply needs to choose the correct values for capacitance （a high value） and load resistance to match the turbine power output. Appropriate operation over a range of wind speeds can be achieved by incorporating a variable resistance and adjusting it depending on wind speed.3.3 Dynamic Behavior. This section examines the transient behavior in self-excitation operation. We choose a value of 3.8 mF capacitance and a load resistance of 1.0 for this simulation. The constant driving torque is set to be ?4500 Nm. Note that the wind turbine aerodynamic characteristic and the turbine control system are not included in this simulation because we are more interested in the self-excitation process itself. Thus, we focus on the electrical side of the equations.Figure 7 shows time series of the rotor speed and the electrical output power. In this case, the induction generator starts from rest. The speed increases until it reaches its rated speed. It is initially 14connected to the grid and at t=3.1 seconds （s）, the grid is disconnected and the induction generator enters self-excitation mode. At t=6.375 s, the generator is reconnected to the grid, terminating the self-excitation. The rotor speed increases slightly during self-excitation, but, eventually, the generator torque matches the driving torque （4500 Nm）, and the rotor speed is stabilized. When the generator is reconnected to the grid without synchronization, there is a sudden brief transient in the torque as the generator resynchronizes with the grid. Once this occurs, the rotor speed settles at the same speed as before the grid disconnection.Figure 8 (a) plots per phase stator voltage. It shows that the stator voltage is originally the same as the voltage of the grid to which it is connected. During the self-excitation mode 3.1 s0,Q>0. (c) Phasor diagram for P>0,Q 0, Q0, Q>0 (the turbine generates both real and reactive power), then < and we may experience saturation.'MS