Electrical Design of a 17 MW Class HTS Motor for Ship Propulsion

A superconducting motor shows several advantages, such as smaller size and higher efficiency, over a conventional motor, especially utilized in ship propulsion applications. However, the size reduction merit appears for large capacity, more than several MW. We develop a large capacity synchronous motor with a rotating high-temperature superconducting (HTS) coil, that is aimed to be utilized for ship propulsion, so it has a low rotating speed of about 200 rpm. The ship propulsion motor must generate high electromagnetic torque instead of low speed. Therefore, the rotor (field) coils have to generate a large magnetic flux that results in a large amount of expensive HTS conductor for the field coil. In this paper a 17 MW HTS motor for ship propulsion is designed with a cost-effective method because the HTS conductor cost is a critical factor in the construction of an HTS motor. Unlike conventional rotating machines, the superconducting motor consists of an iron-coreless structure. Most conventional motors can be designed with small error based on two-dimensional magnetic field analysis. However, the superconducting motor shows an even larger error between the two- and three-dimensional based designs. Thus, in order to improve the design accuracy, we have calculated the back electromotive force (EMF) using 3D magnetic field analysis. An output performance evaluation has also been carried out to obtain a design with higher efficiency.     

Effects of Armature Reaction on the Performance of a Claw Pole Motor With Soft Magnetic Composite Stator by Finite-Element Analysis

We investigated the effects of armature reaction on the performance of a three-phase three-stack claw pole motor with soft magnetic composite stator core by using three-dimensional finite-element analysis (FEA), which is an effective approach to accurately compute the parameters and performance such as the back electromotive force (EMF), core losses, and winding inductance at various saturation levels. The motor is rated as 500 W at 1800 rpm when the stator current is 4.1 A, driven by a sensorless brushless DC scheme. Because of the armature reaction, the back EMF produced by the rotor permanent magnets and the developed torque is reduced by about 3.3% at the rated load, and the core losses increase drastically by 41% from no-load to full-load. The winding inductance is computed with different loads at different rotor angles     

用于电机定子的新型非晶材料铁芯的研究

本文提出一种新方法制作非晶电机定子铁芯。将非晶Fe80Si9B11(Metglas2605SA1)合金带材380℃热处理100min,放入环氧树脂中浸泡1.2h,,在干燥箱中80℃保温2h固化,并切割成定子铁芯;非晶铁芯饱和磁感可达1.36T,在400Hz和1T下的损耗为2.36W/kg,相对磁导率最大值约10000(50Hz),远优于硅钢35DW310最大磁导率值4600(50Hz),且磁导率随着频率变化基本恒定;将非晶和硅钢铁芯装配成5kW电机,非晶铁芯定子相对硅钢装配的电机效率提升了4.6%,输出转矩增加0.18 N.m,测试非晶合金定子电机的反电动势为142V。采用Infolytica软件仿真计算了两种材料作为定子的电机机械特性,电机效率和反电动势计算值与测试值基本一致,非晶合金比硅钢材料定子齿部的磁滞损耗低10倍左右,非晶材料铁损低是电机效率提高的主要原因。     

50-60 Hz electric and magnetic field effects on cognitive function in humans: a review

This paper reviews the effect of 50-60 Hz weak electric, magnetic and combined electric and magnetic field exposure on cognitive functions such as memory, attention, information processing and time perception, as determined by electroencephalographic methods and performance measures. Overall, laboratory studies that have investigated the acute effects of power frequency fields on cognitive functioning in humans are heterogeneous, in terms of both electric and magnetic field (EMF) exposure and the experimental design and measures used. Results are inconsistent and difficult to interpret with regard to functional relevance for possible health risks. Statistically significant differences between field and control exposure, when they are found, are small, subtle, transitory, without any clear dose-response relationship and difficult to reproduce. The human performance or event related potentials (ERPs) measures that might specifically be affected by EMF exposure, as well as a possible cerebral structure or function that could be more sensitive to EMF, cannot be better determined.     

基于单片机的改进型五相混合式步进电机驱动器设计

在高性能纺织机械尤其是电脑绣花机中,步进电机是广泛应用的执行部件.电脑绣花机系统中现有五相混
合式步进电机驱动器存在诸多不足之处低频转矩振荡、高频输出转矩不足和多电源供电等.在分析现有步进电机
驱动器的基础上,结合理论分析,设计出一种基于单片机的改进型五相混合式步进电机W动器.该驱动器使用单一
电源供电,采用三相励磁PWM输出方式,改善了驱动的矩频特性,在电脑绣花机系统中投人应用取得良好效果.     

基于Kano模型和亲和图法的地域性刺绣产品需求研究

目的 探讨中国传统地区刺绣产品如何实现更高的消费者满意度,并为该产品如何实现更多元化的顾客感受提出创新设计的建议。方法 围绕消费者需求偏好,综合采用田野调查、亲和图法、问卷调查法,并结合使用Kano模型、Better-Worse系数、四象限分析法,以及其他相关研究方法,从产品设计、产品生产、产品性能、产品文化四个需求纬度出发,全面准确地把握消费者对刺绣产品的需求。结果 消费者更加看重产品本身的文化属性和产品所提供的优质服务,同时消费者对服务的感受和满足程度会受到一些因素的影响,如绣活文化的保留程度,或是否有独特的个人定制体系。结论 通过Kano模型和亲和图法了解了消费者的真实需求,并且能够更好地实现这些需求。这种方式不仅能够增强消费者的满意度,实现区域特色刺绣产品的传播与普及,也为地域性刺绣产品设计提供了新思路。     

Magnetic Field Analysis of an Ironless Brushless DC Machine

This paper presents an analytical solution for the magnetic field inside an unconventional ironless brushless (ILBL) dc motor design. We discuss the unique characteristics of the design, which adopts an “inside-out” construction with an internal ironless stator. With the intention of obtaining an analytical solution for the magnetic field, we propose a model based on a magnetic pole concept for representing the magnetic circuit. The magnetic field inside the motor, which has no iron for guiding magnetic flux paths, is obtained by solving Laplace's equation for magnetic scalar potential. We present both analytical and numerical solutions for the magnetic field and compare them with measured results of a 20-pole prototype IL design to show the validity of the model. The IL design is simple, easy to manufacture and, as indicated by the results, has an optimum number of magnets, for which its performance becomes maximum.     

A Quantitative Comparative Analysis of a Novel Flux-Modulated Permanent-Magnet Motor for Low-Speed Drive

A novel low-speed flux-modulated (FM) permanent-magnet (PM) motor that breaks the traditional design rule, which stipulates that the number of stator pole pairs and the number of rotor pole pairs must be the same, is proposed. The FM motor has a special physical structure with iron segments in the air gap to modulate the magnetic field. In the design, the free space between adjacent stationary iron segments also acts as ventilating ducts to help improving the heat dissipation and ventilation of the motor. Its cogging torque is very small. In this paper, a rule for comparing the power density of electric motors is proposed. The performance of the FM motor is compared with those of a magnetic-geared PM motor, a traditional PM motor, and a fractional-slot PM motor by using magnetic field finite-element analysis.     

图什业图王府刺绣与潮牌服饰设计耦合

目的 通过将图什业图王府刺绣技艺与潮牌服饰进行设计耦合,使图什业图王府刺绣艺术表达契合现代审美语境,构建图什业图王府刺绣创新发展新样态。方法 借助文献分析与田野调查,对图什业图王府刺绣艺术特征进行归类分析。运用市场调研、文献分析等方法,整合潮牌服饰设计特征与原则,进行设计耦合。结果 通过“祥瑞凤凰”“喜上梅梢”“文武双全”三类图什业图王府刺绣潮牌服饰方案,形成传统工艺与现代审美兼顾的刺绣新形式,构建创新设计流程。结论 将图什业图王府刺绣艺术特征与潮牌服饰进行设计耦合,探索传统刺绣技艺在现代潮流文化中的新形势,实现传统手工艺与潮流文化的结合,从而为蒙古族传统刺绣技艺的发展提供新路径,为振兴中国传统工艺贡献力量。     

A digital method for the determination of the magneticcharacteristic of variable reluctance motors

A digital method is proposed for the measurement of the magnetic flux, starting from the digital integration of the induced electromotive force (EMF). The method features sensitivity and accuracy greater than, or at least as high as, that of other methods, and is applied to the determination of the flux-linkage-versus-current diagrams of a variable-reluctance (VR) motor. Two different methods are proposed to determine flux variations in the motor magnetic circuit, and the results of the experimental work carried out on a typical 4-kW switched reluctance (SR) motor, show that the methods are in good agreement. The methods allow quicker and more accurate determination of the flux-linkage characteristics than other proposed methods, and allow the measurement of flux-linkage values for any value of the excitation current and of the rotor position. For this reason, the methods are useful for the determination of flux-linkage characteristics to be used in the analytical prediction of VR motor performance     

苗族刺绣图案中蕴含的中国传统艺术辩证法

结合刺绣作品予以研究,通过对苗绣作品的图案形象、构图、色彩及表达的内容涵义的探析,提出了苗绣艺术中运用动与静、形与神、虚与实这3组具有辩证关系的美学表现手法营造出具有动感与张力的和谐之美,揭示出中国传统艺术辩证法的运用对苗族刺绣装饰效果的积极影响;中国传统艺术中蕴含的辩证思想及表现手法可应用、转化为符合现代环境的设计语言、设计方法。     

High-performance current control for switched reluctance motors based on on-line estimated parameters

To reduce torque ripple in a switched reluctance motor (SRM) by current profiling, a high-performance current controller is necessary. This study presents a high-performance current controller for SRM drives. A Bspline neural network is used to model the non-linearity of the SRM and estimate back electromotive force (EMF) and incremental inductance on-line in real time. The on-line modelling scheme does not require a priori knowledge of the machine?s electromagnetic characteristics. Based on the on-line estimated parameters, a current controller with adjustable PI gains and back-EMF decoupling is implemented. The performance of the current controller has been demonstrated in simulation and experimentally using a four-phase 8/6 550 W SRM drive system.     

大数据背景下的湘绣设计

目的通过对大数据背景下湘绣设计的现状进行研究,探讨如何利用大数据的优势进行湘绣设计的革新,最终带动行业的发展。方法以湘绣设计的构思、视觉传达、应用设计为基本点,采用实地走访调查、文献研究、数据研究、比较分析法对湘绣设计的现状进行分析研究。通过对大数据基础理论的文献分析、案例分析,结合国家政策,探讨大数据背景下湘绣设计的革新。结论大数据背景下,湘绣设计的革新与发展需要建立政府、企业、个人多层次的数据信息收集与交流平台,通过对数据信息的整合与分析,为湘绣设计的创新与发展提供依据和指导,以建立新的产业生态链。     

转子辅助槽对高速电主轴齿槽转矩的影响机理研究

针对高速永磁同步电主轴中永磁体与有槽铁心相互作用产生的齿槽转矩过高,从而导致电主轴产生振动与噪声的问题,通过在转子齿上开辅助槽来优化电主轴结构.以一台FL系列永磁同步电主轴三相星接Y型电机为模型,利用Ansoft软件对它进行运动仿真和磁场瞬态分析,得到了能有效削弱电主轴齿槽转矩的转子齿辅助槽设计方案.研究结果表明,在转...     

一种平衡衔铁受话器数值仿真分析方法

平衡衔铁受话器(Balanced Armature Receiver, BAR)是一种动铁式扬声器,具有尺寸小、电声转换效率高和灵敏度高等特点。利用平衡衔铁受话器的集总参数模型分析指出平衡衔铁运动会影响反电动势和磁场力,提出一种基于COMSOL Multiphysics的平衡衔铁受话器声压级和阻抗的仿真分析方法。首先对平衡衔铁受话器的磁场特性进行稳态分析,计算得到可随平衡衔铁运动变化的驱动力和反电动势;再对电磁场、结构和声场耦合模型进行频域分析,最终计算得到平衡衔铁受话器的声压级和阻抗。仿真分析结果和测量结果两者基本吻合。     

电磁成形技术的最新进展

电磁成形是目前应用最广泛的高能率成形方法之一.综述了成形磁场力的求解方法及解决电磁成形问题的3个主要方面内容,包括磁场、磁场力及变形,阐述了电磁成形工艺的成形方法及研究现状,列举了大量的国内、外工艺应用及研究成果,介绍了电磁成形工艺的最新应用--电磁校形、粉末压实,并展望了电磁成形技术的发展前景.     

黔东南苗族辫绣图案的符号学探析与设计转化研究

目的 基于莫里斯符号学三分法,分析黔东南苗族辫绣图案的符号特征,旨在探索少数民族刺绣图案在现代文创设计中的应用方法与转化路径,从符号学视域为黔东南苗族辫绣图案的阐释和研究提供更多的思路和借鉴。方法 通过在黔东南苗族地区使用田野调研、文献资料收集、设计实践等方法,对黔东南苗族辫绣图案的工艺、纹饰、色彩等方面的代表性符号特征进行探讨分析,运用莫里斯符号学三分法从语构学、语用学、语义学等层面解读黔东南苗族辫绣图案之间的符号关系,以现代设计实践为方法,从代表性符号元素中提取设计因子,并以文创产品为载体进行设计转化。结论 黔东南苗族辫绣图案的艺术特征鲜明,具有一定的地域特征和审美风尚,从语构、语用与语义等维度对其工艺、纹饰和色彩的符号学要素进行提取衍生,探求黔东南苗族辫绣图案元素设计转化与创新应用的多种可能性,不仅能够使现代设计产品蕴含民族文化特色,而且有助于黔东南苗族辫绣图案自身的传承与发展。     

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.     

Fields, forces, and performance equations of air-core linerself-synchronous motor with rectangular current control

An analytical field approach to determine the permanent magnetic field distribution in a flat air-core self-synchronous linear motor with a permanent magnet mover is reported. Thrust and normal forces are calculated for idealized rectangular-current inverter control. Notable thrust and normal force time pulsations are shown through a numerical example. The performance equations with an on-off current controller are developed with the motor fed from a voltage source transistor inverter. The analysis represents a reliable tool for refined design and control of permanent magnet air-core linear self-synchronous motors     

永磁同步电机全速范围内无传感控制策略研究

目的 为了提高自动化包装生产线的产品效率和质量,改善永磁同步电机无速度传感器矢量控制系统的性能,针对电机运行于低速时反电动势不易检测以及高速位置精度较低的问题,设计一种基于高频方波注入法和改进滑模观测器的复合观测器。方法 在低速时采用高频方波信号注入法来实现对转子位置信息的估计,在中高速时采用改进的滑模观测器来估计转子位置,通过引入双边界层切换函数和可变滑模增益来加快收敛速度和减小抖振,同时设计基于单神经元PI的锁相环用来解析转子信息,进而提高速度和位置,估计精度。结果 通过与单一的算法进行对比分析,发现复合观测器的位置估算精度得到了提高。结论 Matlab/Simulink仿真实验以及实物验证结果表明,和传统的算法相比,该算法具有位置估计精度高、鲁棒性好等优点。