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Intelligent control for large-scale variable speed variable pitch wind turbines

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控制理论与应用（英文版） 2004年第3期2卷 305-311页

作者： XinfangZHANG DapingXU YibingLIU DepartmentofAutomaticControl NorthChinaElectricPowerUniversityBeijing102206China

Large-scale wind turbine generator systems have strong nonlinear multivariable characteristics with many uncertain factors and disturbances. Automatic control is crucial for the efficiency and reliability of wind turbines. On the basis of simplified and proper model of variable speed variable pitch wind turbines, the effective wind speed is estimated using extended Kaiman filter. Intelligent control schemes proposed in the paper include two loops which operate in synchronism with each other. At below-rated wind speed, the inner loop adopts adaptive fuzzy control based on variable universe for generator torque regulation to realize maximum wind energy capture. At above-rated wind speed, a controller based on least square support vector machine is proposed to adjust pitch angle and keep rated output power. The simulation shows the effectiveness of the intelligent control.

关键词： Wind turbines Adaptive fuzzy control Least square support vector machine variable speed variable pitch

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Design of variable screw pitch rib snapping roller and residue cutter for corn harvesters

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International Journal of Agricultural and Biological Engineering 2016年第1期9卷 27-34,I0004页

作者： Wang Gang Jia Honglei Tang Lie Zhuang Jian Jiang Xinming Guo Mingzhuo College of Biological and Agricultural Engineering Jilin UniversityChangchun 130022China Key Laboratory of Bionic Engineering Ministry of EducationJilin UniversityChangchun 130022China Department of Agricultural and Biosystems Engineering Iowa State UniversityAmesIA50011USA

The blocking between two snapping rollers will seriously constrict the harvesting efficiency for corn harvester.A variable screw pitch rib snapping roller was developed to solve this *** comparative experiment between fixed screw pitch rib snapping rollers and variable screw pitch rib snapping rollers illustrated that variable screw pitch ribs can avoid corn-stalk blocking effectively,and it can improve working efficiency by 56.7%.Conservation tillage with standing corn residue was testified that it had a strong control of soil wind *** order to implement this mode of conservation tillage at a production scale,a cutter was developed in this ***,two experiments were conducted,one was to test the cutting ratio(defined as the totally cut off stalk population divided by total stalk population),and the other one was to test standing-residue *** experiment results showed that the mean cutting ratio increased significantly(p<0.05)along with increasing height of cutter-head above the ground(cutting height);the cutting ratio’s mean value increased significantly(p<0.05)along with the decreasing angle between the cutter-head and the ground(cutting angle).The average standing-residue height increased along with the increase of cutting height from 300 mm to 500 *** average standing-residue height increased significantly(p<0.05)along with the decrease of cutting angle from 15°to 0°.Therefore,the newly designed snapping roller can improve the harvesting efficiency and prolong the working life of the cutting table;and the cutter can promote the popularization of the conservation tillage with standing corn residue in Northeast China.

关键词： corn harvester variable pitch snapping roller standing corn residue field imitating experiment cutting height cutting angle

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小型涡轮平面叶栅试验段设计

风机技术 2024年第2期66卷 17-23,61页

作者：季正鑫龙启运祁明旭杨长茂 Beijing Institute of Technology

Performance improvement of the high-load transonic turbine is the key method of improving the thrustto-weight ratio or the power density of gas turbine engines. In order to investigate the flow behaviors inside the high load turbine cascades, a linear turbine cascade test section is designed, which enables the Schlieren photography and static pressure measurement along the cascade profile can be conducted. variable pitch is realized in the test section to achieve different Zweifel coefficients. Due to the capability limitation of the air supplier, the test section is designed to have only5 blade channels with shortened blade height to achieve high Mach number flow conditions. Numerical investigations were carried out to investigate the wall effect and its in fluences on the flow fields inside the test section. The result indicates that the shape of the connecting part of the test section has a significant influence on the flow similarity among different blade passages. With the proper design, a good repetition flow is achieved between neighbored blade passages.

关键词： High-load Turbine Linear Cascade variable pitch Test Section

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PROPER CONDITIONS OF MESHING FOR Hy-Vo SILENT CHAIN AND SPROCKET

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Chinese Journal of Mechanical Engineering 2007年第4期20卷 57-59页

作者： MENG Fanzhong LI Chun CHENG Yabing Chain Transmission Institute Jilin University Changchun 130025 China College of Mechanical Science and Engineering Jilin University Changchun 130025 China

Proper meshing of Hy-Vo silent chain and sprocket is important for realizing the transmission of the silent chain with more efficiency and less noise. Based on the study of the meshing theory of the Hy-Vo silent chain with the sprocket and the roll cutting machining principle of the sprocket with the hob, the proper conditions of the meshing for the Hy-Vo silent chain and the sprocket are put forward with the variable pitch characteristic of the Hy-Vo silent chain taken into consideration, and the proper meshing design method on the condition that the value of the link tooth pressure angle is unequal to the value of the sprocket tooth pressure angle is studied. Experiments show that this new design method is feasible. In addition, the design of the pitch, the sprocket tooth pressure angle and the fillet radius of the sprocket addendum circle are studied. It is crucial for guiding the design of the hob which cuts the Hy-Vo silent chain sprocket.

关键词： Hy-Vo silent chain variable pitch Proper meshing conditions Sprocket tooth pressure angle Sprocket hob Modification coefficient

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