【作者】 宋海辉；

【导师】 田德；

【作者基本信息】 华北电力大学 ， 热能工程， 2014， 博士

【摘要】 随着规模化风电产业的不断发展,陆上常规较高风速以上风能资源的开发利用技术已接近成熟,开发低风速风能资源逐渐成为一个新的研究方向,低风速风能开发对扩大风能利用范围及补充化石能源短缺现状具有重要意义。低风速风能开发利用的核心在于风电机组对低风速风能的捕获效率,研究低风速风电机组叶片翼型优化、风轮气动性能优化,对提升低风速风能转换效率、降低机组成本、均衡机组载荷起到关键作用。本课题在国家科技支撑项目“5.0MW双馈式变速恒频近海风电机组整机设计、集成及示范(2009BAA22B02)”的资助下,围绕低风速风电机组风轮气动优化设计和机组优化控制方法、理论及关键技术开展了如下主要研究工作：(1)基于叶片气动设计理论和遗传算法优化理论,应用遗传算法优化叶片翼型参数,以中低风速风电机组叶片翼型为优化基准翼型,翼型升阻比为优化适应值函数,叶片上下表面的几何控制参数为翼型优化设计变量,经过遗传进化,获得了低风速风电机组叶片优化翼型系列。与基准翼型相比,优化翼型具有较高的升阻比和更大的升力系数。(2)基于Navier-Stokes方程的数值模拟方法,应用GAMBIT和FLUENT软件对优化翼型进行流场数值模拟,研究优化翼型的气动性能,包括翼型周围压力分布、速度分布、升阻力系数,数值分析结果验证了优化翼型的有效性。(3)基于叶素-动量理论,应用遗传算法优化叶片气动设计,以风能利用系数变量dCpmax为优化目标函数,弦长和扭角分布函数系数为叶片优化设计变量,经过遗传进化,获得了低风速风电叶片气动优化模型,并基于该叶片,应用GH Bladed软件,构建3MW低风速风轮动力学模型,分析计算风轮气动性能,结果表明,低风速风电机组风轮具有更高的效率和更宽的高效率区,推力载荷较小,验证了叶片气动优化的有效性。(4)将模糊控制应用于双馈风电机组最大功率捕获和动态载荷控制,在GHBladed软件环境构建3MW低风速风电机组数学模型,设计转速模糊控制器和机组动态载荷模糊控制器,并进行动态仿真,结果显示应用模糊控制能使风电机组有效捕获最大功率和控制动态载荷。构建了一个基于dSACE控制系统的双馈风电机组在环测试平台,在环测试研究采用模糊控制的双馈风电机组性能,实验结果进一步验证了模糊控制在非线性时变的风电机组系统控制上的显著优点。更多还原

【Abstract】 With the consistent promotion of wind resource exploitation, conventional development of comparatively high-wind-speed wind power projects is getting harder and the wind power transmission cost is getting higher. Hence, it becomes a new direction to tap low-wind-speed wind resource. In order to realize distribute wind power feeding into grid, wind power local utilization, to make up for the shortcomings of conventional wind energy utilization, and to complement the deficiency of fossil energy, tapping low-wind-speed wind resource is of great significance.The kernel of exploitation of low-wind-speed wind power lies in the energy capture efficiency of wind turbine generator system (WTGS), optimization of low-wind-speed blade airfoil, and optimization of WTGS aerodynamic characteristics of wind turbine. These are the key to enhance low-wind-speed wind energy conversion efficiency, to lower WTGS costs, and to balance WTGS load. Sponsored by the National Science and Technology Support Project "5.0MW Doubly-Fed Variable Speed Constant Frequency Offshore Wind Turbine Design, Integration and Demonstration"(2009BAA22B02), this research involved optimization method, theoiy and key techniques of aerodynamic design of low-wind-speed rotor and WTGS control. The main contents are as follows:Based on aerodynamic design theory of blades and genetic algorithm optimization, the blade airfoil parameters were optimized, using the mid-low wind speed blade airfoil as the reference base, lift-drag ratio as fitness function, geometric control parameter of upper and lower surfaces as design variables for airfoil optimization. After100generation of generic evolution, finally the low-wind-speed series optimized blades airfoils were obtained. Compared to the reference base airfoil, optimized airfoils had higher lift-drag ratio and better lift coefficient.Based on numerical simulation method of Navier-Stokes equation, softwares GAMBIT and FLUENT were used for simulating air flow field of optimized airfoils and studying their aerodynamic characteristics, which included the pressure distribution around airfoil, speed distribution, lift-drag ratio. The numerical analysis results verified the validity of optimized airfoils.Based on Blade Element Momentum (BEM) theory, the blade aerodynamic design was optimized with genetic algorithm, using rotor power coefficient variable dCpmax as the optimization objective function, geometric chord and twist of airfoil distribution function coefficient as design variables for blade optimization. After generic evolution, the low-wind-speed blade aerodynamic model was obtained. Based on this blade, software GH Bladed was used for constructing a3MW low-wind-speed wind rotor dynamics model to analyze aerodynamic characteristics of the rotor. The results showed low-wind-speed wind rotor had higher efficiency and wider high-efficiency-region, less thrust load, therefore the validity of blade aerodynamics optimization was verified.Fuzzy control was applied in maximum wind energy capturing and dynamic load control of doubly fed induction wind generator system (DFIG). In environment of software GH Bladed, a3MW low-wind-speed WTGS mathematical model was constructed. Fuzzy controller of speed and dynamic load was designed and analyzed using them. Simulation results verified that the optimal wind energy curve occurred with fuzzy control and therefore highest wind energy capturing efficiency. Also, a dSPACE control system based DFIG in the loop test platform was constructed, and tested the characteristics of DFIG. The tests verified further the significant advantage of fuzzy control on onlinear time-varying wind generator control system.更多还原