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针对传统统一变桨距控制策略存在的不足,基于风力机空气动力学原理,提出了基于神经元PID的独立变桨距控制策略,将测量的桨叶根部My方向载荷通过神经元PID控制算出d、q轴的桨距角,经反Park变换得到3个桨叶的附加桨距角,将其与统一变桨距角相加作为独立桨距角的设定值。并借助Fast软件平台以2MW变速变桨风力发电机组为例,仿真比较了独立变桨距控制策略与统一变桨距控制策略。结果表明,独立变桨距控制策略能有效保证在额定转速下机组输出功率稳定,且能有效降低风力发电机组各零部件的疲劳载荷。 相似文献
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在分析风力发电系统能量转换理论的基础上,将单神经元自适应算法与常规PID算法结合,通过单神经元自学习,对PID控制器的系数进行在线调整,提出一种单神经元自适应PID调节变桨角度的控制方法,建立了风力机桨距角控制数学模型.风速超过额定值后,利用单神经元自适应PID控制器进行变桨控制,将控制结果与采用常规PID控制器的控制性能进行了对比.结果表明:单神经元自适应PID控制器可以将输出功率恒定在额定值,能够对变桨系统进行有效控制,达到预期的目标. 相似文献
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为研究风切变和塔影效应对三叶片风力机气动载荷、气动转矩以及输出功率的影响,根据风切变和塔影效应的风速模型,引入等效风速模型,推导分析风力机1P(P为风轮旋转频率)气动载荷和3P气动转矩脉动的形成机理,并基于GH Bladed仿真平台验证这2种脉动的存在性。为减小这2种脉动对风力机产生的影响,基于变桨控制,设计带通滤波器过滤出风力机输出功率的3P脉动分量,并结合方位角信号将其转换为每支叶片的桨距角调节信号,与统一变桨控制的桨距角参考信号叠加,实现基于输出功率和方位角联合反馈的独立变桨距控制。仿真结果表明,所提独立变桨距控制策略不仅能有效缓解风力机1P叶根挥舞载荷脉动,还能明显减小气动转矩和输出功率的3P分量,从而在减小风轮疲劳载荷的同时提高风电机组输出电能质量。 相似文献
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大型风电机组独立变桨控制技术研究 总被引:4,自引:0,他引:4
通过对风力机简化模型的分析,推导出风力机的运动方程和输出方程;通过卡尔曼坐标变换将塔架前后运动方程和载荷输出方程所代表的线性时变系统解耦为线性时不变系统,在此基础上提出带3个独立控制环的独立变桨控制策略;利用"GH Bladed"软件对独立变桨控制策略进行仿真试验研究,仿真试验结果表明,采用独立变桨控制技术不但能实现转速控制功能,还能有效减小叶片根部挥舞力矩、轮毂倾翻力矩、偏航力矩的波动,从而能有效降低变桨轴承、主轴、轮毂、偏航轴承、塔架上的疲劳载荷。 相似文献
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Reliable and powerful control strategies are needed for wind energy conversion systems to achieve maximum performance. A new control strategy for a variable speed, variable pitch wind turbine is proposed in this paper for the above-rated power operating condition. This multivariable control strategy is realized by combining a nonlinear dynamic state feedback torque control strategy with a linear control strategy for blade pitch angle. A comparison with existing strategies, PID and LQG controllers, is performed. The proposed approach results in better power regulation. The new control strategy has been validated using an aeroelastic wind turbine simulator developed by NREL for a high turbulence wind condition. 相似文献
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Subhash C. Mishra N.A. Krishna N. Gupta G.R. Chaitanya 《International Journal of Heat and Mass Transfer》2008,51(1-2):83-90
This article deals with the solution of conduction–radiation heat transfer problem involving variable thermal conductivity and variable refractive index. The discrete transfer method has been used for the determination of radiative information for the energy equation that has been solved using the lattice Boltzmann method. Radiatively, medium is absorbing, emitting and scattering. To validate the formulation, transient conduction and radiation heat transfer in a planar participating medium has been considered. For constant thermal conductivity and constant and variable refractive indices, results have been compared with those available in the literature. Effects of conduction–radiation parameter and scattering albedo on temperature have been studied for variable thermal conductivity and constant and/or variable refractive index. Lattice Boltzmann method and the discrete transfer method have been found to successfully deal with the complexities introduced due to variable thermal conductivity and variable refractive index. 相似文献
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G.C. Wake 《Combustion and Flame》1980,39(2):215-218
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The flow of a fluid in a pipe was treated by Poiseuille and one may find in Landau and Lifshitz a generalization of Poiseuille's solution for a fluid the temperature of which varies in a section. Platten and Legros treat a flow with a variable viscosity, but the expression for the viscosity they use, does not describe the viscosity of a liquid. The solution we propose here concerns the flow of magma, the viscosity of which is a rapidly changing function of temperature. The example we calculate numerically is the flow of the basaltic magma, obeying the viscosity law of liquids and its characteristics are listed in a paper by Hardee. 相似文献
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An up to date review of continuously variable speed wind turbines with mechatronic variable transmissions 下载免费PDF全文
Xiuxing Yin 《国际能源研究杂志》2018,42(4):1442-1454
As a promising and potential alternative to conventional fixed or variable speed wind turbines, continuously variable speed wind turbines (CVSWTs) with variable transmissions offer improved power efficiency and enhanced power control capabilities. The CVSWTs can be generally achieved by adapting mechatronic variable transmissions in the turbine drive train for continuously variable speed operations for wind turbines. Therefore, this paper serves to provide an up to date and exhaustive review of the CVSWTs with mechatronic variable transmissions such as mechanical variable transmission, electrical variable transmission, and power splitting transmission. In this paper, the analysis of CVSWTs with different mechatronic transmission topologies is performed regarding basic configurations, dynamic characteristics, control principles, and experimental or simulation results. Review results indicate the feasibility of applying CVSWTs with such mechatronic transmissions and highlight superiorities of the CVSWTs with power splitting transmission. The CVSWT with power splitting transmission will be particularly suitable for megawatt‐scale turbine systems and will hence increase the economic competitiveness of these turbines due to its large power capacity and high reliability. The directions or challenges for future investigations of CVSWTs with such mechatronic transmissions are also presented to foster in‐depth understanding of such CVSWTs and their control strategies. 相似文献
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变几何涡轮的损失研究 总被引:1,自引:1,他引:0
变几何涡轮与定几何涡轮相比,在静叶顶部多了一个端部间隙,端部间隙大小的选取十分重要,既要保证间隙损失不至于过大,又要保证其能够自由转动,不至于受热而被卡死。所以,在保证静叶能够转动的前提下,静叶的端部间隙应尽可能的小。以某一四级动力涡轮为例,分析了第一级静叶的端部间隙大小以及第一级静叶转角给涡轮损失带来的影响,建议变几何动力涡轮的静叶端部间隙选取为静叶叶高的1.8%。 相似文献
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《International Communications in Heat and Mass Transfer》2002,29(1):141-144
The Squire theorem or Squire transformation is studied under the influence of variable physical properties. It is demonstrated that the Squire theorem can still hold if the parallel base flow and the base temperature are weakly dependent on the flow direction. 相似文献