MODEL AND SIMULATION FOR A BRUSHLESS AC GENERATOR WITH AROTARY RECTIFIER

Objective For a brushless AC generator with a rotary rectifier, it is necessary and significant to model and simulate at normal and fault operation states. Methods Two new concepts, namely, Simulink signals and PSB (Power System Blockset) variables, are proposed, and the difference between the two concepts is clarified. Based on the new model for synchronous machines, a simulation model for a brushless AC generator with a rotary rectifier is constructed by Matlab/Simulink/PSB. This new model, which has a speed input terminal and an exciting voltage input one, can simulate the real electrical characters and direct mechanical connection between two synchronous machines perfectly. The rotary rectifier is a three-phase full-wave bridge rectifier which consists of six diodes. The model for the diodes is a macro-model which possesses much better accuracy than an ideal one of switches. Results Based on the present model, some simulation results such as exciting current waveform, phase current waveform and phase voltbge waveform are afftained at several operation conditions. Conclusion The simulation for a brushless AC generator with a rotary rectifier is demonstrated at normal and fault operation states, respectively. The results confirm the presented method.     

大直径钻孔桩施工工艺

简单介绍了大孔径、深桩基、复杂地质层钻孔灌注桩施工工艺控制,重点论述气举反循环成孔工艺在深桩基钻孔施工中的应用以及采用旁置式漏斗灌注混凝土施工。     

滚动振动试验台电气传动系统研制

为节省投资，研制的电气传统系统利用了６Ｙ２型电力机车的牵引电机、平波电抗及制动电阻设备、极用加馈制动及高精度稳速技术，简化了试验台的结构。本文对该传动系统的机电配置，主电路构成及调节系统结构等关键问题进行了分析和论述。     

钻孔平台在深水群桩基础施工中的应用

以典型工程实例为基础,通过对浮式平台、钢围堰式平台、钢管桩平台、钢护筒平台等各种平台的分析,系统地介绍了各种形式深水群桩基础钻孔平台的应用技术。     

津秦客专隧道钻爆法施工技术

隧道钻爆法施工中不要拘泥于施工图设计给定的施工方案,应根据现场的环境条件、地质条件、断面大小、结构形式、施工工期等因素,灵活选择适宜的施工方法、施工工艺。结合津秦铁路客专隧道施工情况,详细介绍了对钻爆法隧道施工的一些认识。     

基于张吉怀铁路隧道衬砌缺陷控制的新型信息化衬砌台车研究与应用

为有效解决、控制和减少衬砌开裂、掉块、脱空等质量缺陷，保障隧道工程建设安全和运营安全，系统地研发了新型信息化衬砌台车，并形成了以衬砌施工信息为基础的隧道二次衬砌病害控制方法。采用旋转式对接快速分料系统，解决了混凝土离析和施工冷缝问题，提高了混凝土浇注施工效率；采用自动振捣系统，减少了漏振、欠振现象，有利于保证混凝土的密实度；采用V型槽零搭接装置，克服了顶裂施工缝的问题；采用可伸缩式堵头板解决了超欠挖时端模封堵的难题；采用信息采集与控制系统，实现了自动化和信息化施工。试验证明，采用新型信息化衬砌台车能够减少开裂、掉块、脱空等衬砌质量缺陷，有效提高衬砌施工质量。     

转向机构冲击试验台发射机构的开发

按国标GB11557的规定,在进行转向机构冲击试验时,须将规定质量的上半身假人以规定的速度水平发射到转向机构上.文中就这项试验所需的发射机构进行研究,设计了一种钢丝绳牵引式发射机构,并对其关键技术进行探讨.     

Research and application of non-clay low damage temporary bridging drilling/ completion fluids system

Following the basic theory of protecting gas-reservoirs from damage with the temporary bridging technology, inert calcium carbonate (CaCO3) particles, whose diameter is consistent with the size of pores or apertures in the reservoir, were selected as the bridging agent, and modified resolvable starch was selected as filtration loss reducing particles to form the non-clay low damage temporary bridging drilling/completion fluids system (NLTDFS). Under the simulated condition of the well bottom during real drilling, NLTDFS was used to conduct dynamic and static damage experiments of cores for 48 hours, respectively, and then the experimented cores were permeated with pure nitrogen from the undamaged end to the damaged one to measure their recovery of permeability. The results showed that the permeability recovery rate of the core reached 90% or so, and the damaged depth was less than 1 cm, which demonstrates that NL TDFS has higher temporary bridging effectiveness and lower damage to the gas-reservoir than other drilling fluids system. NLTDFS has been used to drill many horizontal wells, and four of them have obtained high yield of natural gas. The yield of natural gas of LPl well reached 85 X 104 m3/day after completion with the rump pipe. The formation of the stable well wall and smooth drilling led to an API loss less than 4 mL and an HTHP loss less than 15 mL.     

铁道机车车辆通用旋转式涡流制动(RWB)

德国铁路公司(DB AG)ICE3快速列车的线性涡流制动(LWB)就是采用了电磁涡流制动的原理.该制动原理的优点是工作无磨损和对环境友好.但铁路日常运输使用LWB制动需强化线路的质量,而使用旋转式涡流制动(RWB)无需强化线路质量,因此原则上可在任何铁道机车车辆上补装RWB系统.多年来RWB作为电磁制动器已成功用于公路机动车辆上.现在已克服了起初所出现的各种的技术难题,在铁路运输中使用这种制动技术已趋于成熟.文章分析了使用旋转式涡流制动技术的可行性和经济性.     

新型水封爆破除尘技术试验研究

为更快速有效地清除隧道钻爆施工所产生的粉尘，提出“辅助降尘注水孔方案”、“差异水袋布置方案”、“降尘注水孔+差异水袋布置” 3种新的水封爆破除尘技术方案。依托轿顶隧道进行现场试验，得到初始状态下掌子面区域纵、横向特征位置的粉尘质量浓度，CO、CO2、O2、NO2体积分数分布情况，通风条件下纵向特征位置的粉尘质量浓度、CO体积分数随时间的变化规律，3种新型水封爆破方案下掌子面区域纵、横向特征测试位置的粉尘质量浓度、CO体积分数分布规律。经研究得出如下结论： 1）通风10 min内是粉尘质量浓度、CO体积分数下降最快的阶段； 2）新型水封爆破除尘方案的降尘效果明显，3种方案最大降尘比例依次为36.84%、40.85%、65.74%； 3）降尘注水孔对爆破粉尘可起到良好的“封闭”作用； 4）新型水封爆破方案可起到明显降低CO体积分数的作用。