薄膜电容在雷达发射电源中的应用

首先,分析了雷达发射电源输入整流滤波电路的特点;然后,对比分析了铝电解电容与薄膜电容在发射电源输入整流滤波电路中应用的优缺点;最后,通过实验对比了两种电容器在电路中的性能参数。实验部分通过完全替代和部分替代两种方式研究了薄膜电容替换铝电解电容后对发射电源输入整流滤波电路的影响,并分析了这两种方案与传统的铝电解电容的优缺点。实验结果表明:在发射电源输入整流滤波电路中,相比于铝电解电容,薄膜电容具有耐高压、损耗小、寿命长等特点。     

海洋平台大功率整流电源电磁兼容整改分析

海洋平台大功率整流电源满功率工作时出现了非正常停机现象,CE102传导发射及RE102辐射发射测试项目超标。综合分析发现,整流电源内部开关器件开关频率及其倍频的电磁干扰、柜体屏蔽性能欠佳是超标的主要原因。通过在整流电源的输入、输出端进行针对性的EMI滤波和屏蔽设计,有效解决了大功率整流电源的电磁兼容问题。     

斩控式整流电源的单片机控制系统

提出一种新的整流电源控制策略,可以使整流电源工作时,从电网输入的电流近似为正弦波,功率因数为1.该控制系统采用8098单片机为主体,适用于象GTR这样具有较高开关速度的大功率电源系统的控制.     

PC电源选购经验谈

在装机时,不少朋友只注重显卡、CPU、主板、显示器、声卡等产品,却忽视了电源的重要作用。电源的基本工作原理目前,ATX电源是标准的开关稳压电源,同传统的线性稳压电路相比,它具有体积小、重量轻、功耗小、转换效率高等特点,缺点是电路复杂、干扰大、波纹系数较大等。一台典型的ATX电源工作模式如下。1.设有输入电网滤波电路,作为电源中的抗干扰电路。2.输入整流滤波电路将交流电整流滤波,为主变换电路提供波纹较小的直流电压。3.主变换电路是开关电源的主要部分,它把直流电压变换成高频交流电压,并起着将输出部分与输入电网     

通信系统电源设计新技术

主要介绍通信系统中低电压大电流电源设计所面临的稳压、散热、输入噪声和成本等方面的问题，分析了多相技术、板上电源、同步整流和次级控制等新技术，给出了一种低电压大电流电源的设计实例。     

多级倍压整流电路的设计原理及其有关参数的计算方法

在许多仪器设备中常需要高电压(如几千伏或几万伏)。为此,我们有必要介绍一下倍压整流电路的设计原理。该电路的整流电源变压器的次级电压并不太高,而整流元件的耐压相对较低,但其输出的直流电压即能高于输入电压的好多倍。 倍压整流电路的种类很多,可以按输出电压与输入电压的倍数,即分为二倍压、三倍压及多倍压电路。     

X光管小型高压电源的研制

本文研究用于X光管的高压电源,该电源采用集成控制芯片,提高了电路的稳定性和抗干扰能力,控制电路产生一定频率的脉冲方波来控制开关电路的通断,脉冲变压器工作,使电压升高,升压后由倍压整流电路进一步提高电压并整流,得到需要的高压。电源输出的电压经分压、取样后连接到控制回路的反馈信号输入端,通过反馈提高电源输出的稳定性。采用以...     

输电线路架空地线取电系统电源变换模块仿真设计

本文为输电线路架空地线取电系统设计出配套的电源变换模块,并对模块电路进行了仿真分析。该电源变换模块可以实现9~100V交流输入到12V直流输出的转换。通过设计整流电路、搭建电路模型、分析电路的输入输出特性,从而得到相对稳定的直流电压源。通过设计电压变换电路将整流电路输出的直流电压进行转换,得到系统所需的12V直流电压,文中优化了电路控制信号脉冲占空比,得到了不同输入电压情况下的最优脉冲占空比,拟合出最优占空比随输入电压变化曲线。     

松下TC-29V30R彩电电源原理分析

<正> 松下TC-29V30R型“新画王”彩电采用M16MV3机心,其电源电路由交流电源整流方式自动切换电路、遥控电源电路、主开关电源及保护电路等四部分组成,其电原理图刊于本刊1997年8期中心插页。下面分别介绍各部分电路的工作原理。 1.电源整流方式自动切换电路 此电路能适应大范围的交流电压变化,其原理电路为图中N—BOARD板电路。其控制机理是:当输入交流电压高于160V时,整流滤波电路工作于桥式整流方式;低于160V时,整流电路则工作于倍压整流方式,从而使整机正常工作在90V～240V的交流电压范围内。该功能电路由交流输入电压检测取样及控制电路、整流滤波电路等构成,其工作过程是:交流市电电压经S—BOARD板中L870、L871、C870、C871、C868、C869等构成的低通滤波器滤除电网上外界高频干扰(同时对开关电源自身产生的高频干扰进行抑制,以免污染电网)后,再经P—BOARD中交流开关S801送到N—BOARD中插排N1,而N1①、②脚间     

一种高效率反激同步整流DC-DC

目前,小型机载电子设备对二次电源体积、输入电压范围、输出电压种类、功率及效率的要求越来越高。基于单端反激拓扑和辅助绕组自驱动同步整流结构,设计了一种多路输出DC-DC电路。分析了多路电源的损耗组成、影响因素和解决措施,以指导电路设计和元器件选型,最终确定系统设计方案。重点对反激变压器设计、同步整流驱动设计和同步整流轻载损耗较大的原因开展分析和研究。实验电路测试结果表明,设计的反激同步整流DC-DC电路满足指标要求。     

Design and fabrication of 2.4 GHz pre-biased rectifier

A 2.4 GHz rectifier operating in a region of low RF input power was developed. The rectifier has a cross-coupled bridge configuration and is driven by a differential RF input signal. Since a rectifier needs an RF signal higher than the threshold voltage of transistors, we introduced a pre-biasing circuit to compensate for the threshold voltage. A low-voltage digital circuit, subthreshold voltage regulator, and low-power level shifter were introduced for reducing the power consumption of the pre-biasing circuit and increasing the driving voltage for the switches at the same time. The circuit simulations revealed that the pre-biasing circuit was effective in a low RF input power region. However, the output voltage was degraded in a high power region. Then, we combined the pre-biased rectifier in parallel with a non-biased rectifier. Three types of rectifiers consisting of LC matching circuits, three-stage rectifier cells, and biasing circuits were designed and fabricated using a 0.18-μm mixed signal/RF CMOS process with one poly and six metal layers. The fabricated pre-biased rectifier operated in a region of RF input power of less than ?15 dBm, while the non-biased rectifier could not operate in this region. The parallel combination of pre-biased and non-biased rectifiers effectively solved the drawback of the pre-biased rectifier in a high RF input power region.     

Vergleich, Dimensionierung und Realisierung einphasiger Power Factor Correctors minimalen Realisierungsaufwands

In the future laws and restrictions will limit the amplitudes of the low frequency harmonics of mains currents of rectifier systems. While diode bridges are very simple, compact and cheap, their input current shows high low-order harmonics. In the past various rectifier systems have been developed that avoid low-order input current harmonics by means of active current control. The significantly reduced input filter results in a small and compact total rectifier system. In this paper different rectifier systems are discussed and compared. Since industry is interested in simple and cheap solutions the rectifier systems are discussed under these considerations. Besides an introduction of different power circuits and control schemes, the systematic choice of the power semiconductors is presented.     

A multilevel buck converter based rectifier with sinusoidal inputs and unity power factor for medium voltage (4160-7200 V) applications

A novel rectifier topology for high power (0.5 to 10 MVA) current source based AC motor drives is proposed. This rectifier is composed of a multi-winding transformer, a multi-level diode rectifier and a modified multi-level buck converter. The rectifier produces near unity input power factor and sinusoidal input current under any operating conditions. In addition, the proposed rectifier features reliable operation and low manufacturing cost. In this paper, the operating principle of the proposed rectifier is introduced. A number of design issues are investigated, which include PWM switching patterns, input power factor and line current harmonic distortion. Some design considerations such as the effect of the line inductance discrepancy on system performance are addressed. Experiments on a 5 kVA/208V four-level prototype are carried out for verification.     

Programmable PFC based hybrid multipulse power rectifier for ultra clean power application

A novel hybrid three-phase rectifier is proposed. It is capable to achieve high input power factor (PF) and low total harmonic input currents distortion (THD/sub I/). The proposed hybrid high power rectifier is composed by a standard three-phase six-pulse diode rectifier (Graetz bridge) with a parallel connection of single-phase Sepic rectifiers in each three-phase rectifier leg. Such topology results in a structure capable of programming the input current waveform and providing conditions for obtaining high input power factor and low harmonic current distortion. In order to validate the proposed hybrid rectifier, this work describes its principles, with detailed operation, simulation, experimental results, and discussions on power rating of the required Sepic converters as related to the desired total harmonic current distortion. It is demonstrated that only a fraction of the output power is processed through the Sepic converters, making the proposed solution economically viable for very high power installations, with fast investment payback. Moreover, retrofitting to existing installations is also feasible since the parallel path can be easily controlled by integration with the existing dc-link. A prototype has been implemented in the laboratory and it was fully demonstrated to both operate with excellent performance and be feasibly implemented in higher power applications.     

Single-switch 3φ PWM low harmonic rectifiers

Existing 3φ AC-DC low-harmonic rectifiers are costly and require complex control schemes to minimize input current harmonics. Introduced here are two new classes of low cost 3φ AC-DC high power factor/low harmonic controlled rectifiers. These are derived from parent DC-DC converter topologies containing boost-type inputs and buck-type inputs. With a single active switch in addition to the diode bridge rectifier, the converters are capable of drawing a high-quality input current waveform naturally at nearly unity power factor. Thus, a simple 3φ AC-DC high power factor rectifier is obtained. Two algorithms are introduced in this paper for constructing a 3φ AC-DC high-quality rectifier. These algorithms depend on the simple switched-mode boost-type input converter and buck-type input converter modified by an input filter. For most known DC-DC converters which belong to these classes, there are corresponding 3φ AC-DC high power factor topologies, which use the same number of transistors and use six additional fast diodes. Analytical and simulation results are supplied to demonstrate the validity of the concept     

High frequency resonant AC/DC rectifier with unity power factor

A novel high frequency switching rectifier, termed the quantum boost series resonant rectifier (QBSRR), is proposed. This rectifier provides the input line AC with a unity power factor. With this proposed scheme, several advantages such as low switching loss and wide output voltage range can be obtained.<>     

Implementation of a three-level rectifier for power factorcorrection

In this paper, a new single-phase switching mode rectifier (SMR) for three-level pulse width modulation (PWM) is proposed to achieve high input power factor, low current harmonics, low total harmonic distortion (THD) and simple control scheme. The mains circuit of the proposed SMR consists of six power switches, one boost inductor, and two DC capacitors. The control algorithm is based on a look-up table. There are five control signals in the input of the look-up table. These control signals are used to control the power flow of the adopted rectifier, compensate the capacitor voltages for the balance problem, draw a sinusoidal line current with nearly unity power factor, and generate a three-level PWM pattern on the AC side of adopted rectifier. The advantages of using three-level PWM scheme compared with two-level PWM scheme are using low voltage stress of power switches, decreasing input current harmonics, and reducing the conduction losses. The performances of the proposed multilevel SMR are measured and shown in this paper. The high power factor and low harmonic currents at the input of the rectifier are verified by software simulations and experimental results from a laboratory prototype     

A high-power-factor, three-phase isolated AC-DC converter using high-frequency current injection

A single-stage, three-phase AC-to-DC converter topology is proposed for high-frequency power supply applications. The principal features of the circuit include continuous current operation of the three AC input inductors, inherent shaping of the input currents, resulting in high power factor, a transformer isolated output, and only two active devices are required, both soft-switched. Resonant conversion techniques are used, and a high power factor is achieved by injecting high-frequency currents into the three-phase rectifier, producing a high frequency modulation of the rectifier input voltages. The current injection principle is explained and the system operation is confirmed by a combination of simulation and experimental results.