一种光伏逆变器的多输出辅助开关电源设计

本文设计了一种光伏逆变器的辅助开关电源。由于光伏逆变器需要的辅助电源路数很多,且要考虑高、低压的隔离,所以设计了两个反激式开关电源。文中介绍了这两个开关电源的计算和设计过程,重点论述了变压器磁芯及绕组的设计、反馈及稳压电路的设计。设计的辅助电源已经用于光伏逆变器上,运行稳定可靠。良好的实验结果证明了设计方法的正确性。     

长洲水利枢纽船闸检修关键技术研究

介绍广西长洲水利枢纽船闸检修关键技术。检修中,通过运用先进的检测设备、现代检测理论与合理的检测方法,调整1#、2#船闸人字门背拉杆和A、B杆,消除了门体运行过程中背拉杆与门体的撞击;通过修磨下游人字门门轴柱支枕垫块,消除挤卡震动现象,从而解决了船闸漏水问题。同时,介绍检修过程中的施工组织与管理,可为同类船闸检修提供参考。     

EXPERIMENTAL INVESTIGATION ON TWO-DIMENSIONAL UNSTEADY COLD FLOW IN MPC EXHAUST MANIFOLD

IntroductionIt is obvious that the gas flow in the exhaustmanifolds,especially at the conjunctions has amulti- dimensional characteristic[1] .The study onthis characteristic is very important for the uti-lization of exhaustenergy and the decrease of ex-haust pumping loss.In this paper,the measure-ment of cold flow has been carried out to studythe multi- dimensional phenomena of unsteadyflow in the exhaust manifolds.In order to em-phasis the important characteristics of the flowand reduce the a…     

RESEARCH ON THE DOF DISPOSITION AND MECHANISMS DESIGN OF HUMANOID ROBOT

IntroductionSome researchers[1～ 3] in Yugoslavia,Japan andAmerica have got many achievements in bipedrobot since the beginning of1 970 s.The bipedrobot can walk in static and dynamic gait and al-so can turn around and go up stairs.Recentlyhumanoid robot has become a hot researchingpoint[4,5 ] .Humanoid robot has body includinghead,neck,waist and hands.Biped robot is abasis of humanoid robot.Usually a humanoidrobot should have more than 2 0 DOF.All thetechnology problems in DOF planning,m…     

AN EFFICIENT BTC IMAGE COMPRESSION ALGORITHM

IntroductionBlock truncation coding( BTC) [1] is a simple andfast lossy image coding technique,which has theadvantage of being easy to implement comparedto transform coding and vector quantization[2 ] .Its simplicity,performance and channel error re-sisting capability make it attractive in the real-time image transmission.BTC is a one- bit adap-tive moment- preserving quantizer that preservescertain statistical moments of small blocks of theinput image in the quantized output.The origi-nal …     

UNCERTAIN KNOWLEDGE MANAGEMENT IN EXPERT SYSTEMS USING FUZZY METAGRAPHS

IntroductionThe fuzzy graph- theoretic constructs are widelyapplied in modeling and analyzing fuzzy sys-tems[1] .Whereas,existing fuzzy constructs arenot suitable for the analysis of the directed rela-tionships between sets of elements.In addition,such relationships widely exist in fuzzy systems,for example,knowledge base in fuzzy expertsystem. So,based on the metagraph proposedby A.Basu and R.W.Blanning[2 ,3] ,this paperpresents a new graph- theoretic construct,afuzzy metagraph and applies …     

PERFORMANCE OF A KIND OF PERMANENT MAGNETIC SUCKERS USED IN WALL-CLIMBING ROBOTS

IntroductionWall- climbing robots with magnetic tracks arewidely used in the fields such as oil tank surfaceinspection,paints spraying shown in Fig.1 .Therobot attaches to the steel wall surface due to anumber of magnetic suckers on both tracks andis driven by the rear chain wheels. In order todecrease the robot's weight and improve its at-tractive ability on steel wall surface,the mag-netic suckers should be small in size,light inweight and powerful in attractive force.Theseare some of the i…     

RSOFCPN: CONTROL SYSTEM STRUCTURE AND ALGORITHM DESIGN

IntroductionThe learning approaches of neural network canusually be distinguished into three classes:su-pervised learning,unsupervised learning and re-inforcement learning.The supervised learningscheme has the highest efficiency but requiresthe learning systems to provide with desired out-puts.Obviously,it is very difficultin many cas-es.Unsupervised learning methods constructin-ternal models at capture regularities in their in-puts without receiving any additional informa-tion.Therefore,its …     

城市区域物流无人机路径规划

针对城市区域物流无人机路径规划问题,采用栅格法进行环境建模,综合考虑无人机性能、任务性质和城市环境等影响要素,以航程、高度变化和危险度最小为目标函数,构建多约束物流无人机路径规划模型.改进A*(A-star)算法求解：为合理预估距离,采用欧氏距离与曼哈顿距离线性组合的方式设计启发函数;为提高搜索效率,引入双向搜索策略;为保证平稳飞行,采用B样条(B-spline)法进行路径优化.结果表明：模型可以实现多目标优化,具有有效性;算法与传统A*算法相比,规划时间少,规划路径航程短,高度变化少,飞行安全稳定.分析参数权重值得出：当3个子目标代价权重系数分别为0.4、0.1和0.5,2种距离权重系数分别为0.15和0.85时,规划路径最优.     

日产风度A32轿车行驶跑偏故障的诊断与分析

详细介绍了一辆日产风度A32轿车行驶跑偏、方向摆头故障的诊断与排除过程。指出对于麦弗逊式独立悬架,在维修过程中应注意因减振器挠性支撑、下臂胶套和球头的老化及磨损而导致的前轮定位参数失常。