Criterion of Magnetic Saturation and Simulation of Nonlinear Magnetization for a Linear Multi-core Pulse Transformer

The linear multi-core pulse transformer is an important primary driving source used in pulsed power apparatus for the production of dense plasma owing to its compact,relatively low-cost and easy-to-handle characteristics.The evaluation of the magnetic saturation of the transformer cores is essential to the transformer design,because the energy transfer efficiency of the transformer will degrade significantly after magnetic saturation.This work propses analytical formulas of the criterion of magnetic saturation for the cores when the transformer driver practical loads.Furthermore,an electric circuit model based on a dependent source treatment for simulating the electric behavior of the cores related to their nonlinear magnetization is developed using the initial magnetization curve of the cores.The numerical simulation with the model is used to evaluate the validity of the criterion.Both the criterion and the model are found to be in agreement with the experimental data.     

TOP开关电源的设计与制作

利用TOP开关器件设计了一种高精度，输出电压可调的开关电源，并介绍了制作方法。     

A novel method of suppressing the inrush current of transformers by using a series‐connected voltage‐source PWM converter

This paper proposes a novel method of suppressing the inrush current of transformers. A small‐rated voltage‐source PWM converter is connected in series to the transformers through a matching transformer. As the connected PWM converter serves as a resistor for the source current, no inrush phenomena occurs. The required rating of the PWM converter, which serves as the damping resistor for the inrush phenomena, is 1/400 that of the main transformers in single‐phase circuits. In three‐phase circuits, it is 1/900. The basic principle of the proposed method is discussed. Digital computer simulation is implemented to confirm the validity and excellent practicability of the proposed method using the PSCAD/EMTDC. A prototype experimental model is constructed and tested. The experimental results demonstrate that the proposed method can perfectly suppress the inrush phenomena. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(4): 56–65, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20174     

皂河抽水站变电所主变保护改造

简要介绍WKT型微机保护装置运行情况、存在的问题及改造方案。根据美国通用电气公司(GE)的SR745微机型变压器管理继电器在皂河抽水站变电所的应用，介绍该装置的主要特点、安装调试中遇到的主要问题及解决方法和运行情况等，并对变压器保护改造进行了有益的探索。     

A new voltage control equipment using fuzzy inference

Power system control equipment needs higher sensitivity and operational reliability. Advanced voltage control equipment is needed for reducing the frequency of tap changes and improving the characteristics (the relationship between the actual voltage and reference voltage) of the voltage to meet today's power system requirements. However, these objectives are in a trade-off relationship. Studies of voltage control derived from a knowledge base suitable for electric power systems can satisfy these objectives using fuzzy inference. Compared with corresponding conventional equipment, the new equipment improved the deviation of 30 min average voltage of 30 percent. This paper describes the design concept of new voltage control equipment using fuzzy inference. In addition, field test results are described along with rules of fuzzy inference, membership functions, and the deviation of 30 min average voltage through detailed simulation.     

浅谈开关电源中的平面变压器

与传统变压器相比较,使用平面变压器可以提高开关电源的功率密度,减小开关电源中磁性元件的体积。因此,近年来平面变压器被广泛地研究。文章介绍了平面变压器的结构,将平面变压器与传统变压器进行比较,分析综述了平面变压器在当今开关电源发展应用的优势和前景,并进一步说明了平面变压器中绕组间距选择,绕组交叉技术及PCB绕组设计等要点。     

《华东电网500 kV变压器全过程管理技术规范>的实施要点

介绍了在执行《华东电网 5 0 0 k V变压器全过程管理技术规范》过程中 ,应强调管理是从基建到生产 ,从选型、安装到运行维护的全过程管理 ,重点介绍了变压器在订货过程中应高度重视诸如对于选用非强油循环的冷却方式、三相共体变压器、抗短路能力以及过励磁问题 ,也对变压器安装过程中水分控制、运行中气相色谱分析和局部放电试验要求作了简述     

精密有源互感器的研制

本文介绍了精密有源电流互感器的原理和设计方法。该互感器的准确度达到０．０１级，线性度优于１×１０－５．     

变压器绝缘电阻低于允许值的处理

本文就一台主变压器绝缘电阻低于“规程”允许值的问题，进行了原因分析，提出了简易的处理方法，取得了较好效果，同时提出了几个值得探讨的问题，对提高变压器的安全运行水平有一定的现实意义。     

Series resonant ZCS‐PFM DC‐DC power converter with high‐frequency high‐voltage transformer link for high‐power magnetron drive

This paper presents a single lossless inductive snubber‐assisted ZCS‐PFM series resonant DC‐DC power converter with a high‐frequency high‐voltage transformer link for industrial‐use high‐power magnetron drive. The current flowing through the active power switches rises gradually at a turned‐on transient state with the aid of a single lossless snubber inductor, and ZCS turn‐on commutation based on overlapping current can be achieved via the wide range pulse frequency modulation control scheme. The high‐frequency high‐voltage transformer primary side resonant current always becomes continuous operation mode, by electromagnetic loose coupling design of the high‐frequency high‐voltage transformer and the magnetizing inductance of the high‐frequency high‐voltage transformer. As a result, this high‐voltage power converter circuit for the magnetron can achieve a complete zero current soft switching under the condition of broad width gate voltage signals. Furthermore, this high‐voltage DC‐DC power converter circuit can regulate the output power from zero to full over audible frequency range via the two resonant frequency circuit design. Its operating performances are evaluated and discussed on the basis of the power loss analysis simulation and the experimental results from a practical point of view. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 153(3): 79–87, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20126