磁芯电感器的谐波失真分析 摘 要：简述了改进铁氧体软磁材料比损耗系数和磁滞常数ηB，从而降低总谐波失真THD的历史过程，分析了诸多因数对谐波测量的影响，提出了磁心性能的调控方向。 关键词：比损耗系数， 磁滞常数ηB ，直流偏置特性DC-Bias，总谐波失真THD Analysis on THD of the fer rite co res u se d i n i nductancShi Yan Nanjing Finemag Technology Co. Ltd., Nanjing 210033 Abstract: Histrory of decreasing THD by improving the ratio loss coefficient and hysteresis constant of soft magnetic ferrite is briefly narrated. The effect of many factors which affect the harmonic wave testing is analysed. The way of improving the performance of ferrite cores is put forward. Key words: ratio loss coefficient，hysteresis constant，DC-Bias，THD 近年来，变压器生产厂家和软磁铁氧体生产厂家，在电感器和变压器产品的总谐波失真指标控制上，进行了深入的探讨和广泛的合作，逐步弄清了一些似是而非的问题。从工艺技术上采取了不少有效措施，促进了质量问题的迅速解决。本文将就此热门话题作一些粗浅探讨。 一、 历史回顾 总谐波失真（Total harmonic distortion） ，简称THD，并不是什么新的概念，早在几十年前的载波通信技术中就已有严格要求<1>。1978年邮电部公布的标准YD/Z17－78“载波用铁氧体罐形磁心”中，规定了高μQ材料制作的无中心柱配对罐形磁心详细的测试电路和方法。如图一电路所示，利用LC组成的150KHz低通滤波器在高电平输入的情况下测量磁心产生的非线性失真。这种相对比较的实用方法，专用于无中心柱配对罐形磁心的谐波衰耗测试。 这种磁心主要用于载波电报、电话设备的遥测振荡器和线路放大器系统，其非线性失真有很严格的要求。 图中 ZD —— QF867 型阻容式载频振荡器，输出阻抗 150Ω， Ld47 —— 47KHz 低通滤波器，阻抗 150Ω，阻带衰耗大于61dB， Lg88 ——并联高低通滤波器，阻抗 150Ω，三次谐波衰耗大于61dB Ld88 ——并联高低通滤波器，阻抗 150Ω，三次谐波衰耗大于61dB FD —— 30～50KHz 放大器， 阻抗 150Ω， 增益不小于 43 dB，三次谐波衰耗b3(0)≥91 dB, DP —— Qp373 选频电平表，输入高阻抗， L ——被测无心罐形磁心及线圈， C ——聚苯乙烯薄膜电容器CMO-100V-707APF±0.5%,二只。 测量时，所配用线圈应用丝包铜电磁线SQJ9×0.12(JB661-75)在直径为16.1mm的线架上绕制 120 匝， （线架为一格） ， 其空心电感值为 318μH（误差1％） 被测磁心配对安装好后，先调节振荡器频率为 36.6～40KHz， 使输出电平值为+17.4 dB， 即选频表在 22′端子测得的主波电平 （P2）为+17.4 dB，然后在33′端子处测得输出的三次谐波电平（P3）， 则三次谐波衰耗值为：b3(+2)= P2+S+ P3 式中：S 为放大器增益dB 从以往的资料引证， 就可以发现谐波失真的测量是一项很精细的工作，其中测量系统的高、低通滤波器，信号源和放大器本身的三次谐波衰耗控制很严，阻抗必须匹配，薄膜电容器的非线性也有相应要求。滤波器的电感全由不带任何磁介质的大空心线圈绕成，以保证本身的“洁净” ，不至于造成对磁心分选的误判。 为了满足多路通信整机的小型化和稳定性要求， 必须生产低损耗高稳定磁心。上世纪 70 年代初，1409 所和四机部、邮电部各厂，从工艺上改变了推板空气窑烧结，出窑后经真空罐冷却的落后方式，改用真空炉，并控制烧结、冷却气氛。技术上采用共沉淀法攻关试制出了μQ乘积 60 万和 100 万的低损耗高稳定材料，在此基础上，还实现了高μ7000～10000材料的突破，从而大大缩短了与国外企业的技术差异。当时正处于通信技术由FDM（频率划分调制）向PCM（脉冲编码调制） 转换时期， 日本人明石雅夫发表了μQ乘积125 万为 0.8×10 ，100KHz）的超优铁氧体材料<3>，其磁滞系数降为优铁
上传时间： 2013-12-15
上传用户：天空说我在
GPR matlab The function should work with MATLAB v 5 and above. Please do not hesitate to contact me with any ideas for improving it or to point out any bugs that you find.
标签： function hesitate contact matlab
上传时间： 2014-01-09
上传用户：zhoujunzhen
13th Israeli Symposium of AI, CV, and NN, Tel Aviv University, Tel Aviv, Israel, Feb. 2-4, 1997 D. Dori, D. Hubunk and Liu W, “improving the Arc Detection
标签： D. Aviv University Symposium
上传时间： 2013-12-23
上传用户：水口鸿胜电器
重构，改善既有代码的设计（英文版）chm格式 Refactoring: improving the Design of Existing Code 中文版的看了很不舒服，到了国外的网站才找到英文版的电子书
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上传时间： 2016-07-25
上传用户：vodssv
This paper deals with the issue of incorporating pseudolite measurements into an integrated Global Positioning System/ Inertial Navigation System ~GPS/INS! positioning and attitude system with a view to improving signal availability, solution reliability, and accuracy in a localized area
标签： incorporating measurements integrated pseudolite
上传时间： 2013-12-10
上传用户：wmwai1314
In this paper we describe a control methodology for catching a fast moving object with a robot manipulator, where visual information is employed to track the trajectory of the target. Sensing, planning and control are performed in real-time to cope with possible unpredictable trajectory changes of the moving target, and prediction techniques are adopted to compensate the time delays introduced by visual processing and by the robot controller. A simple but reliable model of the robot controller has been taken into account in the control architecture for improving the performance of the system. Experimental results have shown that the robot system is capable of tracking and catching an object moving on a plane at velocities of up to 700 mm/s and accelerations of up to 1500 mm/s2.
标签： methodology describe catching control
上传时间： 2014-01-11
上传用户：qq521
Aspect-Oriented Software Developement Coverage includes Using AOSD to streamline complex systems development without sacrificing flexibility or scalability How AOSD builds on the object-oriented paradigmand how it s different State-of-the-art best practices for the AOSD development process Languages and foundations: separating concerns, filter technologies, improving modularity, integrating new features, and more Using key AOSD tools, including AspectJ, Hyper/J, JMangler, and Java Aspect Components Engineering aspect-oriented systems: UML, concern modeling and elaboration, dependency management, and aspect composition Developing more secure applications with AOSD techniques Applying aspect-oriented programming to database systems Building dynamic aspect-oriented infrastructure
标签： Aspect-Oriented Developement streamline Software
上传时间： 2013-12-01
上传用户：jennyzai
Playfair Cipher 1.not even the large number of keys in a monoalphabetic cipher provides security 2.one approach to improving security was to encrypt multiple letters 3.the Playfair Cipher is an example 4.invented by Charles Wheatstone in 1854,but named after his friend Baron Playfair Playfair Key Matrix 1.a 5X5 matrix of letters based on a keyword 2.fill in letters of keyword (sans duplicates) 3.fill rest of matrix with other letters Encrypting and Decrypting -plaintext is encrypted two letters at a time 1. if a pair is a repeated letter, insert filler like X’ 2. if both letters fall in the same row, replace each with letter to right (wrapping back to start from end) 3. if both letters fall in the same column, replace each with the letter below it (again wrapping to top from bottom) 4. otherwise each letter is replaced by the letter in the same row and in the column of the other letter of the pair
标签： monoalphabetic Playfair provides security
上传时间： 2017-05-24
上传用户：变形金刚
I upload Suffix Array Pdf file. This is a really good tutorial for guys who are curious about suffix array. It described the meaning of suffix array and also how to built it. Hope this really help guys improving skills about string searching, string matching, etc
标签： tutorial curious upload Suffix
上传时间： 2013-12-10
上传用户：清风冷雨
AEC-Q100 qualified • 12 V and 24 V battery systems compliance • 3.3 V and 5 V logic compatible I/O • 8-channel configurable MOSFET pre-driver – High-side (N-channel and P-channel MOS) – Low-side (N-channel MOS) – H-bridge (up to 2 H-bridge) – Peak & Hold (2 loads) • Operating battery supply voltage 3.8 V to 36 V • Operating VDD supply voltage 4.5 V to 5.5 V • All device pins, except the ground pins, withstand at least 40 V • Programmable gate charge/discharge currents for improving EMI behavior
标签： configurable Automotive pre-driver suitable channel systems MOSFET fully High side
上传时间： 2019-03-27
上传用户：guaixiaolong
