Conceptual Design of a Field Coil for 5 MW HTS Synchronous Machine

Compared with a conventional rotating machine, a superconducting rotating machine fabricated by High Temperature Superconducting (HTS) tape has superior performance and efficiency due to the HTS field coil for the rotor which can generate high magnetic flux intensity. The two primary factors for the design of the HTS rotational machine are how to construct the optimal magnetic field path through the air gap located between the rotor and the stator and how to enhance the linkage magnetic flux density between the armature coil in the stator and the field coil in the rotor. A 5 MW HTS motor for ship propulsion is planned for development in early 2011 by a Korean collaboration group of KERI and DOOSAN Heavy Industry. As a part of this R&D efforts, we designed and analyzed the field coil for a 5 MW HTS synchronous motor. In this paper, the computational results of the magnetic field distribution on the whole winding regions of the HTS field coil of the superconducting rotating machine will be also presented and discussed.     

Electrical parameter evaluation of a 1 MW HTS motor via analysis and experiments

A 1 MW class HTS (high-temperature superconducting) synchronous motor has been developed. Design concerns of the developed motor are focused on smaller machine size and higher efficiency than conventional motors or generators with the same rating simultaneously reducing expensive Bi-2223 HTS wire which is used for superconducting field coil carrying the operating current around 30 K (−243 °C). Influence of an important parameter, synchronous reactance, has been analyzed on the machine performances such as voltage variation and output power during motor and generator operation. The developed motor was also analyzed by three-dimensional electromagnetic FEM (finite element method) to get magnetic field distribution, inductance, electromagnetic stress and so forth.This motor is aimed to be utilized for industrial application such as large motors operating in large plants. The HTS field coil of the developed motor is cooled by way of Neon thermosiphon mechanism and the stator (armature) coil is cooled by water through hollow copper conductor. This paper also describes evaluation of some electrical parameters from performance test results which were obtained at steady state in generator and motor mode of our HTS machine.     

基于高速机的船舶低振动推进机组设计及试验

针对船舶的高速性、高机动性和低振动要求,选用高速柴油机作为原动机,配置减速齿轮箱、高弹性联轴器、双层隔振装置,组成低振动推进机组.讨论分析机组配置中的技术要求、总体方案设计、关键设备主要技术参数确定、隔振性能计算等关键技术问题,开展机组成套和试验研究,分析试验中出现的齿轮箱振动超标、基座响应指标评价不合理等现象及其原因...     

船舶推进轴系变结构控制

以船舶主推进轴系为研究对象,在变结构控制理论和设计方法的基础上,对主推进轴系的变结构控制方法进行研究。考虑到推进轴系在螺旋桨处的位移响应最大,在螺旋桨部位设置主动控制作动器,对推进轴系进行振动控制,并以主推进系统的弹性体动力学模型为基础,建立系统的变结构控制方法。采用单位向量控制形式的最终滑动模态控制器,并采用二次型最优控制理论设计最终滑动模态的切换函数。最后以一个带有六个弹性支撑的推进轴为例进行仿真计算。实例分析指出:变结构控制对于推进轴系的振动控制具有显著的效果。     

Design and AC Loss Analysis of a 22.9 kV/50 MVA Class Triaxial HTS Power Cable

Recently, triaxial high temperature superconducting (HTS) power cables have become a mainstream design in the development of HTS cables because of several advantages, such as the reduced amount of HTS wire, low leakage fields, and compactness, when compared with other types of HTS cable. Unlike the AC loss from other types of HTS cable, the AC loss from the triaxial HTS cable is influenced by the magnetic fields of other phases, as the triaxial HTS cable does not have a shield layer between the phase conductors. The authors have designed a 22.9 kV/50 MVA class triaxial HTS power cable. The AC loss and the magnetic characteristics of the triaxial HTS power cable are analyzed using the Comsol program, a commercial finite element method. To confirm the characteristics of the triaxial HTS power cable by wire type, the characteristics of two wire types were applied to the FEM model.     

某超高层建筑电气设计实例

本文结合新近完成的超高层工程实例,提出了超高层建筑电气设计的特殊关注点,并就配电方案、供电可靠性、设计管理、节能等问题给出了解决方案.     

Design optimization of a HTS current lead with large current capacity for fusion application

Design study of a high temperature superconductor (HTS) current lead having a large current transportation capacity has been performed for thermonuclear fusion application on the basis of a 60 kA HTS current lead developed by Japan Atomic Energy Agency. The lead consists of copper and HTS parts, and the conductors of the parts are a forced flow cooled bundle and conduction cooled cylindrically arrayed stacks of silver-alloy sheathed Bi-2223 tapes for the copper and the HTS parts, respectively. The objective of the design study is to reduce cost for fabrication and operation of the HTS current lead by computing the optimum HTS operating temperature, where the total amount, including increase of fabrication cost and decrease of operating cost by adoption of HTS lead, is minimized. Results of the study show that HTS operating temperature of 75 K is optimum for 10,000 h operation and reduction by 1/5 of electric power consumption for a conventional lead can be achieved at the temperature.     

Design of Trimmingless Narrowband Planar HTS Filters

The use of high temperature superconductor (HTS) films provides a higher selectivity of planar filters. The lower out-of-band interference increases the sensitivity of receiving systems and allows reduction of transmitter radiated power. Our goal was to show how these filters can be designed with a desired accuracy, and to give evidence for a real possibility of designing the trimmingless planar HTS filters. The analysis of filter performance is based on accurate models of the characteristics of the HTS planar transmission lines. The HTS film and substrate characteristic tolerance sensitivity is investigated. The design procedure of the trimmingless filter is proposed. Mass production of such filters requires a specific certification of the substrate materials and HTS films used.     

HTS电力技术应用中的液氮高电压绝缘特性研究

针对超导电力装置的低温高电压绝缘问题,通过低温高电压实验装置系统地研究了液氮的绝缘与击穿特性,重点研究了电极形状、电极间距和液体压力等因素对液氮击穿特性的影响规律。结果表明:电极间距越大击穿电压越高;击穿电压随气体压力线性增加;电极形状对室温液氮的击穿电压影响显著,电极间隙的电场越均匀击穿电压越高;电极距离的增大引发电极间隙电场均匀性变差,单位长度的耐压强度随长度的增加而降低;液体压力的增高,不同电极的耐压能力都有不同程度的改善。     

Experimental Design for a Class of Accelerated Degradation Tests

Traditionally, reliability assessment of new devices has been based on accelerated life tests. This approach is not practical for highly reliable devices, such as lasers, which are not likely to fail in experiments of reasonable length. An alternative approach is to monitor the devices for a period of time and assess their reliability from the changes in performance (degradation) observed during the experiment. In this article, we propose a methodology for designing experiments for degradation processes in which the amount of degradation over time levels off toward a plateau (maximum degradation) that is a function of stress. We provide (a) the stress levels for the experiment, (b) the proportion of devices to test at each stress level, (c) the times at which to measure the devices, and (d) the total number of devices to test. We apply the proposed methodology to an actual example.     

Simplified Design Methodology for a Slotless Brushless DC Motor

The paper presents a simplified analytical method to design a small two-pole slotless brushless dc motor. Using only a few approximations, the motor analytical model is formulated to generate a system of equations. The system can be solved analytically, producing a motor design for given specifications. The method is used to design a motor with the specifications 150 W, 10 000 rpm, and 18 V     

船舶推进装置气囊隔振系统对中可控性问题研究

本文对船舶推进装置气囊隔振系统对中可控性问题进行了系统研究。通过建立控制响应计算模型、多目标对中控制模型,提出了对中可控性分析方法,使得控制系统能够根据不同工作情况自主调整控制系统工作参数,以保持良好的对中控制收敛性能,并通过实验验证了该方法的可行性。该方法已应用于某型船舶推进装置气囊隔振系统,成功实现了气囊柔性支撑状态下的推进装置高效隔振。     

Analysis of a Premature Failure of a Hub from a Diesel Generator of a High-Speed Motor Ship

Failure analysis is carried out on a fractured hub obtained from a diesel generator of a high-speed motor ship. Macrofractography, microfractography, standard optical metallography, material characterization techniques, and numerical modeling were used to verify the findings of the current investigation. Cracking initiation is attributed to fretting fatigue caused by a modification performed in the vicinity of the fractured hub. Operational vibrations contributed to the propagation of the cracks as typical fatigue cracks until final fracture.     

一种新型电动机隔声罩

本文介绍一种新型电动机隔声罩。其特点在于将隔声罩内腔设计成更接近轴流风机气流通道的形状，从而改善散热性能；同时也采取了更有效的降低噪声措施，试验效果良好，可供参考。     

实用船体型线设计系统的研发与功能实现

系统利用计算机图形平台来模拟船体数学放样和手工光顺,用Beta样条和B样条两种技术来拟合型线,实现船体水下部分型线的交互设计。系统可自动读取型值表中的数据,直观方便地进行各个站点型值点的参数化交互设计,实时记录和保存修改结果,自动更新后台数据文件型值表,并自动绘出水下部分船体型线。系统在绘图的同时自动生成曲线插值的数据文本文件和图形的DXF文件,使图形的输出可以方便与AutoCAD接口。     

船舶集控室虚拟仿真系统的设计与实现

在分析现有虚拟现实技术与船舶集控室的基础上,采用3D-MAX与XNA分别实现了三维模型的建立与虚拟场景的漫游和交互,应用C#语言编写了集控室的二维模拟软件,通过UDP协议实现了三维虚拟场景与二维模拟软件之间的通讯.根据光照效果的数学模型,采用高级着色语言(HLSL)开发了一种基于GPU的着色器,降低了GPU与CPU之间的传输负荷,增强了虚拟场景真实感.     

轴承刚度对船舶推进轴系振动传递路径影响分析

采用传递矩阵法,将船舶推进轴系简化为质量点单元、弹性支承单元和具有分布参数的梁单元。基于修正的Timoshenko梁理论,推导出推进轴系的场传递矩阵表达式。然后,引入相应的边界条件,形成方程组并实现不同轴承刚度下推进轴系轴承处的力和位移响应求解。最后,从能量的角度,对推进轴系各轴承传递路径处的功率流进行分析,并与有限元结果比较。结果表明:基于修正Timoshenko梁理论的传递矩阵法在计算推进轴系弯曲振动时是可行有效的;艉后轴承刚度对轴系振动传递影响最大,艉前轴承次之,推力轴承影响最小。     

一种新的包装机电机算法切换系统设计

目的 研究不同工况下包装机生产线中异步电机控制算法的在线灵活切换。方法 选用2种异步电机高性能控制策略FOC和DTC作为包装机电机算法的切换对象,研究2种算法的共同基础,得出新的FOC_DTC算法作为切换系统的过渡算法,有效解决2种控制策略在线相互切换带来的转矩、电流突变等问题,并且在硬件平台上与直接切换方案、重置PI切换方案进行对比。结果 在满足包装机各个工况要求的前提下,混合FOC_DTC切换系统在切换响应时间、切换平滑度和切换效率上比上述2种方案更优越,切换响应时间提高了2%,切换转矩尖峰降低了30%。结论 通过使用混合FOC_DTC切换系统,包装机在不同工况下可以在线实时切换动力系统电机的控制算法,在平滑度和响应时间上比其他方案有明显的优势。     

国内外电机能效技术标准化发展概况分析

结合电机能效发展现状,分析了欧盟、中国、美国电机能效技术标准的使用范围和等级分类,其中对电机能效测试的三种常规测试,包括温升试验、空载试验、负载试验进行了详细说明。本文将有助于进一步提高我国电机能效水平。     

Design of high efficiency mixed refrigerant Joule–Thomson refrigerator for cooling HTS cable

The substitution of high temperature superconducting (HTS) cables for existing subterranean electric transmission lines is arising as a solution to continuously increasing electricity demand in urban areas. A cryogenic refrigeration system having the characteristics of high reliability, high efficiency, large cooling capacity, and low capital cost is essential to enable such a substitution. These requirements can be satisfied with a mixed refrigerant Joule–Thomson (MR JT) refrigerator. Unfortunately, usual MR JT refrigerators exhibit good performance at refrigeration temperatures above 80 K. A precooled neon–nitrogen MR JT refrigerator is proposed in this paper that can cool HTS cables at 70 K. The coefficient of performance (COP) of the proposed MR JT refrigerator is predicted to be 0.058 at 70 K (19.2% for exergy efficiency) with the optimized design variables. The COP can be improved further to 0.064 by enhancing the efficiency of the precooling cycle. The maximum achievable COP demonstrates the feasibility of MR JT refrigerator for cooling HTS cable.