互感器的作用与特性分析

互感器通过电磁耦合关系,将一次侧的电能传输到二次侧去,低电压二次系统与高电压一次系统实现电气隔离,提供低电压,小电流信号实现电路控制.笔者提醒：电压互感器二次绕组不能短接,电流互感器二次绕组不能开路.     

基于ANSYS Maxwell仿真变压器绕组振动受力分析

为了研究负载状态下变压器绕组振动受力分布及大小,对变压器绕组进行了电磁仿真与电磁力分析。电磁仿真使用了有限元软件ANSYS中的电磁场分析模块Maxwell,利用有限元电磁仿真得到一次额定电压下的绕组铁芯电磁密度云图及各绕组感应电压与电流,从而确定各个绕组负载状态下所受电磁力及分布,为研究变压器振动噪声提供了理论基础。     

高频感应加热用旋压式夹持器

夹持器是把高频感应器装夹在高频淬火变压器二次侧绕组上的一种夹紧工具,将高频感应电热设备产生的高频电流传输给高频感应器,进行零件的高频感应加热。 高频感应加热所使用的感应器夹持器种类很多,我厂自1965年至1979年曾先后使用过螺栓压板式、偏心压紧轮式和插入式三种夹持器,由于这几种     

北京第一机床厂自制电渣焊变压器成功

北京第一机床厂根据电渣焊接工艺的要求,自己设计,自己施工,就地取材,试制成功一台容量150仟伏安的土变压器,一次电压380/220伏,二次电压调整范围69～78/40～45伏,输出电流调整范围300～2500安。经过实际使用,效果很好。变压器的工作原理同一般磁分路式电焊机一样,电压是靠调整一次或二次线圈匝数的多少来调节,电流是     

DN_7-5、DN_7-10、10/220V型减轻触电单相农用变压器

该变压器一次输入电压为10kV,二次输出电压为220 V,二次线圈绕组中间抽头经触保器接地。当人畜发生触电时,触电电压由原来的单相对地220 V 降到110 V 以下,从而大大减轻了人畜触电伤害程度。采用该变压器供电,缩短了低压线路供电长度,降低了低压线路综合损耗(一般可降低6％～10％),减轻了农民的电费负担,较三相四线制供电可节电10％。     

某光伏行业多晶硅还原炉变压器烧毁实例分析

针对多晶硅还原炉变压器三相运行时的不平衡能力问题和调功柜电源工作时,调整线圈抽头会产生高次谐波等引起变压器线圈局部过热的绝缘问题,采用了低压侧最大档到最小档抽头电流线圈,按照“由外向内顺序靠近铁芯排列”布局,同时将各相高压线圈做成上下部两个线圈、中间分开应用制造技术;通过对还原炉变压器A相高压侧线圈和三相低压侧线圈层间短路故障数据的研究,分析了还原炉变压器绕组结构的合理布局与线圈绝缘能力好坏的关系,提出了改善绕组排列和铁芯结构工艺、增加外部风扇散热等方法;在制造工艺及运行条件上,针对还原炉变压器与调功柜配合所产生的高次谐波量进行了专门设计.最后,通过现场改善变压器运行环境及工艺结构等技术措施进行了试验,结果表明,变压器的抗谐波及不平衡能力得到增强,后期未再出现短路烧毁事故.     

基于LCC的谐振式无线电能传输负载无关性研究

为了给安装在旋转部件上的电子设备进行供电,探究无线供电技术能否对负载进行稳压输出.依据互感模型,建立了耦合线圈发射侧等效电路,计算出系统接收侧和总系统的阻抗表达式,并进一步计算出系统中发射侧和接收侧输出电流的计算公式.通过电流计算公式与各谐振网络之间的关系求出系统的谐振频率以及满足系统输出的各电路参数.仿真结果表明,在特定谐振频率下,当互感恒定时,发射线圈电流仅与系统的输入电压有关,即原边线圈可保持恒定的电流,有利于形成稳定的磁场,有利于电路稳定运行,由此可得输出电压具有负载无关性,易于实现恒压控制.通过仿真与实验,验证了对该电路分析结果的正确性.     

阻抗匹配平衡变压器

该变压器是一种新型平衡变压器,构思新颖,采用阻抗匹配方法,控制各绕组电流分布,并协调好非等相变换的原副方电压和电流的向量关系,实现了原方三相对称系统对副方两相平衡(相位相差90°)系统的转换。该变压器具有对电力系统负序影响小、容量利用率高和承受过载能力大等特点,适     

智能随器无功补偿控制器

基于配电变压器无功补偿完成了一种智能无功补偿控制器的硬件设计,装置以MSP430F133单片机为核心,安装在配电变压器的低压侧,实时监测电流、电压和功率因数,按无功需求控制多组不同容量的补偿电容进行投切.与以往控制器投切方式和补偿方式相比,提高了补偿精度以及设备的利用率.经实际运行表明,变压器二次侧功率因数控制在0.95 ～0.98之间,达到了预期的效果.     

电流信号加法器

１概述目前,国家电力部门正在大力推广"低压电容无功功率自动补偿"系统,采用低压电容器无功补偿是国家和企业节约电能保证电网供电质量的一条根本途径。如果无功损耗的补偿搞成自动化,将予示企业节能工作的管理跨入了一个新的技术高度。在变压器并联线路上求取总电流信号,通常都是在变压器一次侧,即高压侧,装置高压电流互感器取出电流信号送给计量仪表,进行一次计量。要想实现二次侧总计量,只能把各台变压器二次侧均装设电流互感器和计量仪表,分别计量,再通过人工统计、累加算出总耗能。为解决这个问题,我们在变压器低压侧采用"…     

非接触电能传输关键技术研究

非接触电能传输采用电磁耦合感应的方式进行电能传输,具有无磨损、可靠性高、柔性好、安全性高及使用寿命长的特点。非接触电能传输系统研究的主要问题是提高传输效率和适用性。建立了基于互感参数的耦合模型,用反映阻抗分析了初次级电路的相互能量交换及相互影响。研究了功率补偿的方法和适用范围,对初次级绕组进行了详尽的补偿分析,设计了初次级绕组的补偿方案。对耦合环节进行了实验研究,利用平面变压器技术,将线圈整合在电路板上,在保证传输效能的基础上,有效减小了传输系统的体积。     

Complex magnetic susceptibility setup for spectroscopy in the extremely low-frequency range

A sensitive balanced differential transformer was built to measure complex initial parallel magnetic susceptibility spectra in the 0.01-1000 Hz range. The alternating magnetic field can be chosen sufficiently weak that the magnetic structure of the samples is only slightly perturbed and the low frequencies make it possible to study the rotational dynamics of large magnetic colloidal particles or aggregates dispersed in a liquid. The distinguishing features of the setup are the novel multilayered cylindrical coils with a large sample volume and a large number of secondary turns (55 000) to measure induced voltages with a good signal-to-noise ratio, the use of a dual channel function generator to provide an ac current to the primary coils and an amplitude- and phase-adjusted compensation voltage to the dual phase differential lock-in amplifier, and the measurement of several vector quantities at each frequency. We present the electrical impedance characteristics of the coils, and we demonstrate the performance of the setup by measurement on magnetic colloidal dispersions covering a wide range of characteristic relaxation frequencies and magnetic susceptibilities, from chi approximately -10(-5) for pure water to chi>1 for concentrated ferrofluids.     

Application of an impedance matching transformer to a plasma focus

A plasma focus was constructed using an impedance matching transformer to improve power transfer between the pulse power and the dynamic plasma load. The system relied on two switches and twelve transformer cores to produce a 100 kA pulse in short circuit on the secondary at 27 kV on the primary with 110 J stored. With the two transformer systems in parallel, the Thevenin equivalent circuit parameters on the secondary side of the driver are: C = 10.9 μF, V(0) = 4.5 kV, L = 17 nH, and R = 5 mΩ. An equivalent direct drive circuit would require a large number of switches in parallel, to achieve the same Thevenin equivalent. The benefits of this approach are replacement of consumable switches with non-consumable transformer cores, reduction of the driver inductance and resistance as viewed by the dynamic load, and reduction of the stored energy to produce a given peak current. The system is designed to operate at 100 Hz, so minimizing the stored energy results in less load on the thermal management system. When operated at 1 Hz, the neutron yield from the transformer matched plasma focus was similar to the neutron yield from a conventional (directly driven) plasma focus at the same peak current.     

双管反激电源的分析与设计

针对反激电源主开关管关断时候的电压应力过大和变压器气隙漏感导致的电压尖峰过大的问题,对双管反激电源的拓扑结构及工作原理进行了详细分析,构建了双管反激电源工作在DCM模式时的能量传递模型,论证了变压器匝比与变压器原边漏感的磁复位时间及最大占空比和回馈能量大小的关系,推导出了双管反激电源主要参数的通用设计公式;利用其设计公式,设计了一个实际工作于DCM模式的30W双管反激电源,同时利用Saber仿真软件,研究了双管反激电源的主开关管、副边整流二极管和原边续流二极管的工作电流。仿真结果表明：变压器匝比参数选择合适,充分削弱了通过续流二极管回馈的能量,电源工作稳定。将仿真结果与实验样机所测结果进行了比较,结果显示两者基本吻合,说明设计公式可用作双管反激电源主要参数的设计工具。     

Note: Tesla transformer damping

Unexpected heavy damping in the two winding Tesla pulse transformer is shown to be due to small primary inductances. A small primary inductance is a necessary condition of operability, but is also a refractory inefficiency. A 30% performance loss is demonstrated using a typical "spiral strip" transformer. The loss is investigated by examining damping terms added to the transformer's governing equations. A significant alteration of the transformer's architecture is suggested to mitigate these losses. Experimental and simulated data comparing the 2 and 3 winding transformers are cited to support the suggestion.     

Characterization of a linear device developed for research on advanced plasma imaging and dynamics

Within the scope of long term research on imaging diagnostics for steady-state plasmas and understanding of edge plasma physics through diagnostics with conventional spectroscopic methods, we have constructed a linear electron cyclotron resonance (ECR) plasma device named Research on Advanced Plasma Imaging and Dynamics (RAPID). It has a variety of axial magnetic field profiles provided by eight water-cooled magnetic coils and two dc power supplies. The positions of the magnetic coils are freely adjustable along the axial direction and the power supplies can be operated with many combinations of electrical wiring to the coils. Here, a 6 kW 2.45 GHz magnetron is used to produce steady-state hydrogen, helium, and argon plasmas with central magnetic fields of 875 and/or 437.5 G (second harmonic). In order to achieve the highest possible plasma performance within the limited input parameters, wall conditioning experiments were carried out. Chamber bake-out was achieved with heating coils that were wound covering the vessel, and long-pulse electron cyclotron heating discharge cleaning was also followed after 4 days of bake-out. A uniform bake-out temperature (150?°C) was achieved by wrapping the vessel in high temperature thermal insulation textile and by controlling the heating coil current using a digital control system. The partial pressure changes were observed using a residual gas analyzer, and a total system pressure of 5×10(-8)?Torr was finally reached. Diagnostic systems including a millimeter-wave interferometer, a high resolution survey spectrometer, a Langmuir probe, and an ultrasoft x-ray detector were used to provide the evidence that the plasma performance was improved as we desired. In this work, we present characterization of the RAPID device for various system conditions and configurations.     

PCB平面变压器漏感与自互感精确仿真

从变压器完备的自互感模型出发导出漏感表示式,表明精确的自互感模型是漏感精确估值的前提。通过电磁仿真软件CST电磁工作室叼寸一个四绕组多层PCB平面变压器模型的自互感进行仿真计算,说明上述结论。     

基于L6565的准谐振反激式变换器设计方法

为了提高开关电源的功率密度,减小开关电源的体积和电磁干扰(EMI),降低功率开关器件的导通损耗,介绍了一种基于16565的准谐振反激式变换器.利用功率开关管自身的输出电容与变压器原边电感产生谐振,通过适当的控制实现了开关管的零电压导通.与传统的反激式硬开关变换器相比,它能有效地减小开关损耗,提高变换器的效率.     

弧焊变压器谐波研究

在对弧焊变压器进行理论分析的基础上建立了综合励磁支路非线性、磁滞、涡流损耗和漏电感等因素的变压器通用模型。根据弧焊变压器磁滞回线的测试结果,对弧焊变压器的稳态谐波电流进行计算,结果表明弧焊变压器空载谐波电流的主要成分为三次谐波。针对这一结果,提出抑止谐波污染的措施。     

一种任意正交折线线圈阻抗的解析建模新方法

提出了一种位于导体上方正交折线线圈的阻抗解析建模方法。首先,在前人研究的基础上,定义了外形位置因子,得出了单矩形线圈的入射场感应电压及散射场电压简化计算方法;其次,将多个矩形线圈自感电压及两两之间的互感电压叠加,建立了串联等效电感模型;再次,根据任意正交折线线圈的几何原理,将该线圈拆解为有限个相同截面的矩形线圈并进行重构,得出入射场阻抗及散射场阻抗的广义二重积分表达式。最后,利用Mathematica对回折线圈实例进行了计算与实验比较,并根据影响阻抗的各个变量绘制阻抗平面图。拆解重构方法可用于不同形状、不同激励频率、不同提离高度的正交折线线圈平行置于任意电导率导体上方的阻抗解析计算。