Trends in active power line conditioners

Active power line conditioners, which are classified into shunt and series ones, have been studied with the focus on their practical installation in industrial power systems. In 1986, a combined system of a shunt active conditioner of rating 900 kVA and a shunt passive filter of rating 6600 kVA was practically installed to suppress the harmonics produced by a large capacity cycloconverter for steel mill drives. More than one hundred shunt active conditioners have been operating properly in Japan. The largest one is 20 MVA, which was developed for flicker compensation for an arc furnace with the help of a shunt passive filter of 20 MVA. In this paper, the term of “active power line conditioners” is used instead of that of “active power filters” because active power line conditioners would cover a wider sense than active power filters. The primary intent of this paper is to present trends in active power line conditioners using PWM inverters, paying attention to practical applications     

高功率脉冲变压器设计

简要介绍了高功率脉冲变压器,讨论了国内外该领域相关研究现状,总结了高功率脉冲变压器设计中减小上升时间及顶降,展宽输出脉宽,提高耐压性能及能量效率的方法和闭路磁芯的应用.为了使高功率脉冲变压器具有高能量传输效率,且输出波形上升时间短,脉冲宽度宽,本文采用具有高磁导率和高饱和磁感应强度值的磁性材料制造的闭路磁芯,并在变压器...     

电子电力变压器在光伏发电系统中的运用分析

随着社会经济的不断发展,人们对于电力能源的需求量逐年上涨,传统的化石能源,由于其储量有限,且应用过程中会对环境产生较严重的影响,故应用和开发新能源势在必行.光伏发电是一种用可再生性的清洁能源,通过电子电力变压器接入微电网中,使其具备了一定的事故运行能力,并增强了系统的稳定性和安全性.文章对电子电力变压器在光伏发电系统中的运用进行了分析.     

High-frequency power transformer model for circuit simulation

A model for the circuit simulation of transformers used in high-frequency power processing is proposed. Many important transformer effects are combined in a single formulation. An Atherton-Jiles model with improved minor-loop handling ability is employed to simulate the hysteresis effect in the magnetic core. Eddy currents and skin and proximity effects are simulated by dynamically approximating the field and flux distributions in the entire structure. Leakage fluxes, capacitive couplings and the influence of temperature on electric and magnetic materials are also included. The parameters needed for simulation are magnetic material characteristics, available in data sheets, core geometry and winding geometry. The model was implemented (built) in the source code of SPICE3     

CMOS RF power amplifier with reconfigurable transformer

A CMOS RF power amplifier that can change the output transformer ratio is presented. The CMOS power amplifier is fully integrated in a 0.13 /spl mu/m process and has a power added efficiency (PAE) of 38% at 2.1 GHz and an output power of 30.7 dBm with 3.0 V supply voltage. The PAE at an output power of 16 dBm was increased by 40% by altering the transformer ratio.     

单端反激式开关电源变压器

基于反激式变压器拓扑原理,设计了单端反激式变压器,用于电缆绝缘电阻测试仪高压电源的DC-DC逆变升压模块.提出单端反激式开关电源变压器设计时一些关键参数的选择原则和设计步骤及验证方法,总结了设计过程中的一些注意事项.使用结果表明:该设计方法在简化和明确变压器设计过程的同时,所设计的变压器应用于绝缘电阻测试仪升压模块中约250 V的逆变升压时表现出稳定的升压性能.     

10kV配电变压器防窃电监测装置

针对10kV高压供电、低压计量用户的窃电现象,提出一种算法用以判断窃电行为是否发生。基于此算法设计一种装置,以解决供电部门对特定用户供电的监测。该装置可以准确地记录与分析用户的用电状态,达到对疑似窃电用户进行震慑和监管的目的。     

High and dry [Dryformer power transformer]

In this paper the authors describe Dryformer, an innovative high-voltage transformer design that, by eliminating the need for oil, promises a host of performance and environmental benefits     

电力电子变压器运行与控制研究

电力电子变压器为基于电力电子变换器的高频变压器,是一种可取代传统工频变压器的新型技术。电力电子变压器不仅具备功率传输、电气隔离功能,且可通过变换器控制系统的优化设计,实现多项辅助功能。文中论述电力电子变压器的运行和控制策略。基于文中提出的控制策略,电力电子变压器可实现功率的双向、精确调控,并兼具无功功率、不平衡电流等辅助补偿功能。     

Current control strategy for power conditioners using sinusoidal signal integrators in synchronous reference frame

In this paper, a current control scheme, based on proportional-integral regulators using sinusoidal signal integrators (SSIs), is proposed for shunt type power conditioners. The aim is to simplify the implementation of SSI-based current harmonic compensation for industrial implementations where strict limitations on the harmonic distortion of the mains' currents are required. To compensate current harmonics, the SSIs are implemented to operate both on positive and negative sequence signals. One regulator, for the fundamental current component, is implemented in the stationary reference frame. The other regulators, for the current harmonics, are all implemented in a synchronous reference frame rotating at the fundamental frequency. This allows the simultaneous compensation of two current harmonics with just one regulator, yielding a significant reduction of the computational effort compared with other current control methods employing sinusoidal signal integrators implemented in stationary reference frame. A simple and robust voltage filter is also proposed by the authors to obtain a smooth and accurate position estimation of the voltage vector at the point of common coupling (PCC) under distorted mains' voltages. The whole control algorithm has been implemented on a 16-b, fixed-point digital signal processor (DSP) platform controlling a 20-kVA power conditioner prototype. The experimental results presented in this paper for inductive and capacitive loads show the validity of the proposed solutions.     

谈电力变压器的局部放电交接性试验重要性

本文旨在探讨电力变压器的局部放电交接性试验重要性,从局部放电的危害、局部放电交接性试验的功效两个方面进行探讨分析.从目前笔者多年电力运维检修实践经验来看,研究成果已具备,但仍存在一定的问题.这项试验对于电力变压器的安全运行中各个环节来说,都具有关键性的作用,需要引起运维管理人员的重视.     

基于人工免疫算法的变压器故障诊断方法

人工免疫系统是一种由生物免疫系统启发的学习外界物质的自然防御机理的学习技术。基于人工免疫识别原理提出一种电力变压器故障诊断方法,利用增加抗原、记忆抗体类别信息等方法对变压器故障样本进行学习,获取更多表征故障样本特征的记忆抗体集并进行分类。经过对故障数据的Matlab实验,将结果与IEC三比值法进行比较,表明该算法有较高的诊断准确率。     

基于人工免疫算法的变压器故障诊断方法

人工免疫系统是一种由生物免疫系统启发的学习外界物质的自然防御机理的学习技术.基于人工免疫识别原理提出一种电力变压器故障诊断方法,利用增加抗原、记忆抗体类别信息等方法对变压器故障样本进行学习,获取更多表征故障样本特征的记忆抗体集并进行分类.经过对故障数据的Maflab实验,将结果与IEC三比值法进行比较,表明该算法有较高的诊断准确率.     

Integrated circuit transmission-line transformer power combiner for millimetre-wave applications

A new approach for power combining several low-voltage CMOS amplifiers using a new on-chip transmission line transformer structure is presented. The power combiner utilises the interconnection of short sections of integrated differential lines and has an efficiency independent of the transformation ratio. Full-wave electromagnetic simulation confirms the operation and low insertion loss of the transformer     

电力变压器的绝缘电阻测量与分析研究

本文主要分析了绝缘电阻测量试验的方法和对试验时的注意事项,并对试验结果进行了具体分析研究.在实际运用中对电力设备的绝缘测量的判断进行分析,按照电力设备相关试验规范及试验要求对电力设备进行预防性试验的检查与维护,以准确诊断、排查设备缺陷.通过试验可以验证变压器能否在额定条件下长期运行,并且能够承受预期的各种电压及电流的作用而不影响变压器的寿命,确保正常的生产.     

Design of a high-frequency planar power transformer in multilayertechnology

A high-frequency power transformer using multilayer printed circuit board (ML-PCB) technology is presented for applications in switched-mode power supplies operating at frequencies up to several megahertz. The mechanical configuration of laboratory prototypes is discussed, as well as the electrical, parasitic, and thermal behavior. The focus is on the leakage inductance, since the analysis of other aspects is relatively simple. Test results show that the transformer has high efficiency, low leakage inductance, good thermal behavior, and good line insulation properties. The topology enables the designer to make a trade-off between leakage inductance and interwinding capacitance. Due to the well-defined geometry, parasitic interwinding capacitance and leakage inductance are reproducible and can be computed relatively easily     

级联型电力电子变压器控制策略研究

电力电子变压器是一种新型的电能转换工具,它可以利用电力电子转变技术来实现传统变压器的功能.基于此,本文对级联型电力电子变压器进行了简单的研究,并根据其自身特点制定对应的控制策略.