Integrated Control Strategy for Dual State Continuously Variable Transmission System

Continuously variable transmission (CVT) is the ideal transmission for automobile, it is also one of the most important research items of researchers and automobile companies all over the world. In order to research vehicle with torque converter as starter and metal pushing belt as high speed transmission equipment(dual state CVT system), based on the test data of engine and torque converter, the integrated control strategy for vehicle with dual state CVT system is proposed and integrated control simulation for car with dual state CVT system is finished at the condition of multi mode. The research results provide the theory method of analysing and designing for CVT vehicle.     

Wind Loads Distribution on Typical Vaulted Shells

The distribution characteristics of shape factors and fluctuating wind pressure coefficients on two vaulted shells were investigated by simultaneous measurement of external and internal wind pressures on static models in wind tunnel. The effects of orifices on bottom and blocking at ends on wind loads distribution are discussed. It is shown that the wind pressure distribution is significantly affected by changes on orifices at bottom and blocking at ends. Wind pressure on ends decrease effectively and wind pressure on surface is distributed smoothly by blocking ends with highly curved surface shell. Small orifices at bottom not only contribute to degreasing negative pressure because of count acting effects of internal and external pressures, but also to extending the positive pressures region and increasing positive pressures. Wind loads suggestions on these structures are described at end.     

通辽市固日班花风电场风能储量分析

为了开发科尔沁沙地的风能资源,为其治理提供便捷、安全的能源,利用科尔沁沙地最典型地区奈曼旗固日班花风电场测风塔和奈曼气象站的风向、风速资料,对固日班花风电场的风能储量进行分析。结果表明,固日班花风电场塔高10、60、65、70、80 m处的年平均风速订正后分别为4.9、6.8、7.0、7.2、7.3 m/s;相应风功率密度分别为136.5、315.4、341.3、365.6、382.1 W/m2。逐月风速与逐月风功率密度年内变化规律基本一致。风电场风能资源较为丰富,达到了建设大型风电厂的要求。     

安徽省最大风速时空分布不均匀性分析

利用安徽省近30年逐日最大风速资料,对安徽省最大风速集中度（MWSCD）和集中期（MWSCP）时空分布不均匀性进行了分析,最后讨论了影响安徽省MWSCD异常时的环流特征,结果发现：安徽省大部MWSCD多在0.06上下,其中山区MWSCD相对较低。淮北和江淮之间中东部MWSCP主要集中在18~24候之间,山区的MWSCP较晚,多集中在24~28候之间,MWSCD和MWSCP空间的差异主要是受地形分布影响的。MWSCD具有明显的年际变化,其高值年与低值年环流差异的对比上,高值年对流层高层,中国河套以西和以东为“+-”位势高度距平控制,同时对应一个气旋性环流和一个反气旋性环流,安徽处在气旋性环流的中心地带,对流层中层,安徽处在偏北风异常控制之下。在对流层低层,安徽省处在负异常位势高度的西南侧,在西北风的控制之下。     

Research of Wind Load on the Surface of YingLi Building in Chongqing

Considering the complicated distribution of wind load on the surface of the tall building, the 1:300 scale model test of YingLi building is completed in the No.2 environment wind tunnel, which belongs to the State Key Lab of Environmental Engineering College, Beijing University. Based on the calculation and analysis of the test results, this paper discusses the coefficient of wind-induced vibration and shape coefficient of wind load , gives the maximum and minimum value of surface wind load, which can be used for the wind resistant design and insure the security of the building under 100 years return period wind load.     

Research on the Body Coefficient of Complicated Tall Buildings

Considering the complication of the coefficient of wind-induced vibration for tall buildings,the scale 1:300 model test of Ying Li Building is completed in the second wind tunnel of Beijing University.Based on the calculation and analysis of the test results,the static and dynamic wind pressure acting on the building can be obtained and the value of the coefficient of wind-induced vibration for this tall building can be solved directly,thus a new way is laid for the research of complicated tall buildings.     

Analysis of wind load spectrum of super tall buildings with round section in hilly terrain wind field

In order to get wind load and wind induced response of super tall buildings in hilly terrain wind field, effect of changing of turbulent intensity on wind loads must be known. 4 kinds of turbulent wind field are simulated, and 3 super tall building models with round section of different aspect ratio are manufactured. Effects of turbulent intensity, aspect ratio and layer height on along-wind and across-wind load are discussed. Different models are used in fitting of wind load spectrum on each direction. Parameters of load spectrum models are secondary fitted based on turbulent intensity and aspect ratio. Mathematical models of wind load spectrum of super tall buildings with round section in hilly terrain are preliminarily established. At last, an example is provided. According to vertical profile of mean velocity, turbulent intensity and mathematical model of wind load spectrum, wind induced dynamic response of super tall buildings in hilly terrain and flat terrain are compared.     

山东潍坊地区的一次大风冰雹强对流天气分析

为了更好地研究潍坊地区强对流天气的发生发展机制及特点,减少大风冰雹等灾害性天气带来的危害,为日后的春夏季节强对流天气预报工作提取可利用的预报指标,提高预报准确率,特对此次强对流天气过程进行诊断分析。本文利用常规气象资料进行剖面和探空分析,同时结合雷达和卫星云图等短时临近数值预报产品进行成因分析,得出此种强对流天气的发生特点和类型。结果表明,此次强对流天气的产生的重要原因是东北冷涡东移过程中分列出的高空槽。冰雹发生在2日的下午,此时低层升温明显,能量充足。前倾结构的高空槽使高层干冷空气叠加在低层暖湿空气上,导致不稳定层结出现,从而触发了强对流天气的发生。     

风廓线雷达资料在沈阳冰雹天气过程中的分析应用

本文利用风廓线雷达的基本产品、Micaps实况资料和区域自动站资料,对沈阳城区发生的一次冰雹天气过程进行分析,结果表明：此次冰雹是在冷涡背景下,高空存在横槽、逆温,触发的局地的强对流天气过程。降雹前高空由西北风转为偏西风,预示着横槽的到来,风廓线雷达对冷空气侵入的判别提前于常规观测资料。1000 m以下水平风的变化与降雹时间及强度有较好的对应。高空水平风速≥12 m/s的风速带在降雹前1h达到峰值。高空急流区在冰雹发生前20~25min出现急流动量下传,为冰雹的产生提供动力条件。降雹阶段探测高度明显增加,主要是由于空气湿度增大和高层存在大量冰晶粒子所致。冰雹过程中,冰晶粒子主要集中在1900 m以下。降雹前25min垂直风切变增大,并在降雹前20min达到极值,垂直风切变的变化与急流的变化相对应。垂直速度达到极值对应的并不是降雹的开始,低层信噪比＞60 dB,对应降雹开始,信噪比对于冰雹的敏感程度比垂直速度高。垂直速度大于4 m/s与降水的开始、结束时间有着很好的对应关系。     

从输电阻塞角度建立的风电场容量可信度模型

风电并网时既要考虑系统的可靠性又要考虑输电阻塞。目前风电场容量可信度仅从可靠性单一角度提出。为此从输电阻塞角度提出了风电场容量可信度的定义;通过Monte Carlo法建立计及元件故障(发电机、线路和变压器)的风电场容量可信度模型,并提出该模型的二分法求解算法;同时还提出了风电阻塞指标以描述风电场并入电力系统对缓解系统输电阻塞的贡献。通过对修改的IEEE-RTS进行算例分析,验证了方法的正确性和实用性。结果表明：系统阻塞状况的缓解程度与并入风电场的位置有关,风电场容量可信度和风电阻塞指标相结合可以评价风电场并网对系统阻塞状况改善的有效性和经济性。     

Independent pitch control strtegy anlysis of MW wind turbine

Under rel circumstnces, wind sher, tower shdow nd other fctors led to unblnced lods on wind wheel plne nd lrge tip displcement. While trditionl wind turbine control strtegy cnnot effectively solve the problem of uneven lod. In view of this, n individul pitch control strtegy is proposed by combining the liner qudrtic regultor with the disturbnce ccommodting control. Then this control strtegy is simulted under the environment of FAST nd Mtlb/Simulink softwre. Results show tht the proposed strtegy of individul pitch control cn reduce lods of min components nd improve opertionl life of wind turbines under wind sher cses.     

Numerical simulation on low calorific value coal-bed gascombustor and structural design optimization

This paper conducts the full size three-dimensional combustion numerical simulation study on the low-calorific value coal bed gas combustor. It explors the effects of different ratios of swirling wind and straight wind on flow field,temperature field and concentration field when this combustor combusts coal bed gas which methane volume concentration is 30 percent. The optimal ratio of swirling wind and straight wind is gained. Based on this,the number and obliquity of cyclone vane in gas pipeline are further optimized. The results show that when ratio of straight wind is 80 percent and ratio of swirling wind is 20 percent,the good jet flow rigidity is not only possessed,but also the strong spin momentum is brought. Reverse axial velocity grads and reverse velocity in central backflow region are also big,the burning temperature and combustion efficiency are high,and high-temperature region is diffusely distributed. When the number and obliquity of cyclone vane are respective 6 and 60,the mass fraction of methane descends quickly,the mass fraction of methane is low in outlet of combustion region,and the combustion efficiency is high.     

Arrangement and design of main bearing for wind turbine

The wind turbine bearing runs under complicated loading and vibration condition and its design and analysis is a developing and crossing discipline. The typical main bearing arrangements for wind turbine are compared, including the 3-point arrangement with spherical roller bearing, double-row tapered roller bearing and cylindrical roller bearing, two single-row tapered roller bearings. The various factors including the wind turbine type, loading, cost and weight are considered in the design of wind turbine drive train. The influencing factor of bearing reliability and the relationship between wind load, drive train and bearing are studied. Based on an example of bearing reliability, the influence of complicated topography on wind load and bearing life is analyzed. The commonality of the wind farms with wind turbine failure is found, i.e. the topology and the wind condition of most wind turbine sites are very unfavorable, e.g. with sleep slope, not enough distance between adjacent wind turbines. Such factors can cause abnormal wind shear and turbulence, which can bring unexpected load onto the bearing. The key factors in the analysis procedure of topography and wind resource are discussed.     

The analysis of rotating blades effect onwind turbines macelle wind measurement

To improve the accuracy of wind measurement, computational fluid dynamics is adopted to simalate the impact of wind turbine blades with and without T-spoilers on the outflow field distribuation and the wind speed and direction measurement on the top of macelle. The simulation is arried out on a 5 MW wind turbines when the rated wind speed is 10.5 m/s and the rated speed of blades is 11.34 r/min. The calculation results show that the blades with T-spoilers have greater impact on the accuracy of anemometer and wind vane on the top of nacelle. Therefore,it’s recommended to move forward the wind measurement equipment 0.3 m and elevate them 1 m relative to the original position so that the measurement accuracy meets the design requirements.     

张家口地区风特征分析

为了揭示张家口地区风向风速时空分布特征及主要变化趋势,为该地区合理利用风资源、减轻风灾提供参考,利用1960—2013年张家口地区14个气象站风速风向观测资料,借助数理统计、线性拟合、气候倾向率等方法,对该区域的风特征进行了统计分析。结果表明,张家口地区年均风速坝上地区为3.6~4.1m/s,大于坝下地区的1.8~3.0m/s。年均风速变化总体呈减小趋势,54年间坝上与坝下地区分别减小了2.21m/s与0.92m/s,最大减小幅度均出现在20世纪70年代。年均风速呈“春季大、夏季小”的分布类型,平均风速最大、最小值分别出现在4月和8月。年均风速冬季减小速率最大,夏季最小。风速日变化坝上地区13—15时、坝下地区15时左右达到最大,凌晨5—7时风速最小,一天中平均风速上午的增长率与午后的下降率,坝上地区均大于坝下地区。坝上四县年均大风日数为48.5天/县,坝下为31.8天/县,大风日高值时段发生在1963—1974年间,坝上与坝下地区大风日数分别以9.4d/10a与7.1d/10a的速率减少。张家口地区全年以NW、偏北和偏西风向为主,市区、各县春季和冬季主导风向一致,夏季和秋季主导风向一致;进入夏季,随着暖湿气流的增强,张家口市偏南和偏东风出现频率有所增加。     

Gear-bearing coupling dynamics characteristics of wind turbine planetary gear transmission system under variable load

Considering that the transmission system of wind turbine works in complex and changing load environment caused by stochastic wind speed,this paper uses sparse least squares support vector machine(SL-SVM) to simulate wind speed of true wind field,and obtains time-varying wind load caused by stochastic wind speed. The lumped-parameter method is used to develop a dynamic model of planetary gear transmission system of wind turbine coupled with bearing. The model includes the varying wind load,time-vary mesh stiffness of gear pair and time-vary stiffness of rolling element bearing. The numerical method is used to simulate the dynamic performance of planetary gear system of Multibrid Technology Wind Turbine with 1.5 MW rated power. The vibration displacement responses of the transmission system are obtained as well as dynamic meshing force each pair of gear and nonlinear bearing forces. The research can provide a foundation for optimizing dynamic performance and reliable design of gear transmission system of wind generator.     

Wind Tunnel Test and Numerical Simulation of Wind Induced Loads on Complex Shaped High Rise Buildings

Taking a complex shaped high rise building as a case, the wind tunnel test with rigid model was carried out for wind load study. Meanwhile, with Fluent 6.1 software, the CFD numerical simulation had been performed with the RSM and the Non equilibrium Wall Functions. It was found that the results of the two methods were in good agreement. There were mainly positive pressures on the windward surface and negative pressures on the roof, the leeward surface and the side. Especially, negative pressure was higher in the leeward region at the building corner. And at the wind angle of 180°, the wind speed amplification effect was remarkable which was similar to those of canyons.     

Simulation of Wind Loading for Large - span Bridge Structures

Wind speed time series obtained with numerical simulation methods are adopted in structural analysis of wind - induced vibration. In this paper, based on the natural wind properties and the correlativity of nodal wind speed time series, AR model is employed to simulate wind speed time series, and the AIC rule is used to fix the rank of the AR model. Statistical analysis results of numerical wind speed time series show that AR model is efficient in simulating nodal wind speed time series which has time and space correlativity, and that the simulation precision, simulation efficiency and calculation stability answer the needs of practical engineering.     

An improved rotor side control strategy of double fedwind turbine generation system

Based on a on site wind turbine’s output active power vs. generator speed curve, the shortage of conventional power control strategies of doubly fed wind turbine generation system are analyzed. Considering the generator speed restriction and active power fast track control requirement, the power decoupling control strategy in the rotor side converter and variable pitch control strategy are improved, that is, an output mechanical torque of wind turbine and the generator speed of DFIG are used in the rotor side active power control loop in order to achieve an accurate optimal speed control, as well as a direct active power control method is also adopted in the variable pitch control strategy. Finally, the overall operational performances of DFIG wind turbine generation system using the proposed control strategies are simulated, and also compared with the conventional control strategies. The results show that the improved control strategy is more valid and correct.     

海上大风延伸期预报研究进展

海上大风是海洋产业的重大灾害性天气,而延伸期预报是世界性难题。目前,延伸期预报主要分成动力延伸、低频振荡、经验波传播、数理统计、气候扰动分解和集合预报等6种方法,以动力延伸中的数值模式和低频振荡中的MJO监测诊断最为流行。随着大数据时代的到来,基于大数据分析,以数值预报产品为基础的集合预报成为未来业务发展的重点方向。这6种方法都可以用于海上大风等重大灾害性天气预报,许多学者尝试较多的是气候扰动分解、低频振荡中的低频天气图等方法中的溯源技术,通过找到源头,实现重大灾害性天气的延伸期预报。