消除输入浪涌电流的“软启动”

通常在开关电源启动时,可能需要输入端的主电网提供短时的大电流脉冲,这种电流脉冲通常被称为"输入浪涌电流(inrush current)"。输入浪涌电流首先给主电网中的断路器(Main Circuit Breaker)和其它熔断器的选择造成了麻烦:断路器一方面要保证在过载时不能熔断,避免误动作。其次输入浪涌电流会产生输入电压波形塌陷,使供电质量变差,进而影响其它用电设备的丁作。通常输入浪涌电流没能引起系统工程师在选择电源时足够的重视,从而可能导致此后一些难以预计的情况发生。PULS(普世)的研发人员开发了一种有效的方法来限制输入浪涌电流,并应用到该公司推出的DIMENSION概念型产品当中。这种方法有效地消除了输入浪涌电流,实现了开关电源无害的"软启动"。     

全桥式开关电源的一种切断式过流保护电路

本针对桥式开关电源存在同一相桥臂上的功率ＭＯＳ管直接短路的危害，提出桥式开关电源的一种切断式过流保护电路，不仅可以避免不同相桥臂上功率ＭＯＳ管过流的损坏，还可以避免同一相桥臂上功率ＭＯＳ管过流的损坏。最后，本给出设计和分析。     

几种实用的直流开关电源保护电路

本文从原理和实验两方面对直流开关电源进行了研究,根据其应用特点,阐述了各种保护电路的设计方法,提出了系统设计的原则和整机保护的措施,介绍了几种实用的保护电路。     

开关电源软启动电路的设计与应用

本文分析了开关电源启动时的瞬时冲击电流。阐述了应用不同器件设计的开关电源软启动电路及开关电源软启动实用电路。     

开关电源的软启动电路

开关电源的输入电路大都采用电容输入型整流电路。在电源合闸接入瞬间,由于电容器上的初始电压为零,电容器充电会形成很大的瞬时冲击电流(如图1所示),特别是大功率开关电源,其输入采用较大容量的滤波电容器,其冲击电流可达100A以上。在电源接通瞬间,如此大的冲击电流幅值     

一种高精度开关电源研究

本借助高频等效电路分析了ＤＣ／ＤＣ开关电源电路中的浪涌电压，并得了三阶特性方程，利用根轨迹法，分析了特征方程。用ＲＣ平面描述了浪涌电压机被抑的区域。考虑到吸收电路的损耗后，能得到优化的吸收电路的电阻和电容值。据此研制的开关电源输出电压噪声极小。     

开关电源的软起动电路

介绍开关电源冲击电流的影响及几种防止冲击电流的软起动电路。     

高可靠性DC-DC开关电源的浪涌电流抑制电路设计

本文通过分析DC-DC开关电源中浪涌电流形成的原因,介绍了目前广泛应用的各种浪涌电流抑制方案;并重点介绍了基于高端领域平台用DC-DC电源所采用的两种浪涌抑制电路设计,并通过试验结果验证了此两种电路设计方案的特点及有效性。     

开关电源中电流检测电路的探讨

介绍电流检测电路的实验方法,并探讨在电流检测中常遇见的电流互感器饱和、逼边电流下垂的问题,最后用实验结果分析了升压电路中电流检测的方法。     

DC-DC开关电源模块并联供电系统

为设计一种DC-DC开关电源并联供电系统,采用DC-DC主从模式实现两个开关电源的并联供电,并按比例自动分配电流。设计采用STC12C5A60S2单片机完成A/D采集主从模块及其总电流,再通过D/A控制从模块的电流,以实现主从模块按比例输出电流供给负载。DC-DC主从模块是由开关电源控制芯片SG3525为核心完成PWM产生,BUCK拓扑结构和反馈电路组成。这个系统实现可手动或自动调节电源比例的并联稳压供电,最大输出可达到4 A-8 V直流,效率高达83%。介绍了系统结构、DC-DC主从模块、测量电路、系统供电以及主控机原理,详细介绍系统结构、DC-DC主模块和主控电路。     

Expandable interleaved high voltage gain boost DC-DC converter with low switching stress

In this paper, an interleaved DC-DC step-up boost converter with high voltage conversion ratio and low voltage stresses on switches and diodes is proposed. The proposed converter has low average current passing through the diodes and switches and low input current ripple as a feature of interleaved converters. The voltage gain of the proposed converter can be increased by adding more diode-capacitor modules; therefore, the proposed converter has expandable structure. In addition, by implementing more diode-capacitor modules, the switching stresses would be more decreased. Also, to evaluate the performance of the proposed converter, it is compared with other similar presented circuits in the literature. The proposed converter is not only able to provide higher voltage gain but also has lower voltage stresses on switches and diodes. Consequently, switches and diodes with low voltage ratings can be selected. Theoretical analysis is provided in this study for each operation mode and the average current through the switches, diodes and inductors, voltage stresses on switches and diodes, voltage gain, and input current ripple are calculated. Finally, to demonstrate the accuracy performance of the proposed converter, a 450-W prototype is implemented practically.     

一种高摆幅软启动线性稳压源设计

基于0.5μm工艺设计一种带软启动电路大摆幅输入电压的线性稳压源(LDO),为解决高电压输入时LDO输出节点的瞬态过冲电流问题,设计一种在缓冲器的输出端加入MOS开关的软启动方案,提高电路的安全可靠性。通过仿真分析,结果表明该电路在输入电压10~40 V变化,其线性调整度为7.5 m V@30 V,输出5 V稳定电压,负载电流范围0~10 m A,输出电流1~10 m A,瞬态变化时负载调整度为12 m V@9 m A。电源电压上电时间为1 ms时,LDO的输出过充电流不超过6 m A。     

基于预充电的电容器组投切控制策略

为了减小配电网中无功补偿并联电容器组投切时所引起的涌流和过电压,对电容器组的投切过程及其自适应控制进行了研究,提出一种采用普通接触器的投切策略.该策略利用电网特性,通过二极管支路预先使三相电容器中的两相充电,使得一个周期内三相电压波形存在唯一一个同时过零点.在该过零点投入电容器组,能有效降低合闸涌流及过电压.仿真表明,采用该策略投切电容器,电容器合闸涌流被限制在2.5 p.u.以下,电压波形畸变很小.通过添加二极管支路预充电能有效地改善电容器组投切时的暂态性能,从而延长电容器的使用寿命.     

A zero-current switching switched-capacitor DC-DC converter with reduction in cost,complexity, and size

This paper presents a new step-up switched-capacitor (SC) DC-DC converter which has many advantages such as reduction in investment cost, control complexity, number of components, voltage stress on components, and size over traditional topologies. In the proposed structure, power switches are reduced in number which in turn leads to the merits mentioned earlier and makes the converter more suitable for industrial applications. Furthermore, a previously introduced zero-current switching (ZCS) method is used here which provides soft switching for the devices. There is also a reduction in the number of required inductors to achieve ZCS due to the decreased number of switches in the proposed converter. The proposed converter is validated by comprehensive simulation results in MATLAB Simulink environment and also precise experimental results which show the acceptable performance of the proposed topology.     

一种输入电流连续的新型高增益DC-DC升压变换器

高增益DC-DC变换器正越来越多地应用于太阳能光伏或其他可再生能源发电系统。良好的稳态和动态性能以及更高的效率,是为上述应用选取变换器的先决条件。为此,提出一种高增益DC-DC升压变换器。首先,详细阐述了该新型变换器的拓扑结构与工作原理,在此基础上,对其电路参数进行了设计。然后,将所提变换器与最近提出的其他类似变换器在各种性能参数上进行了比较。最后,采用Matlab软件建立了系统仿真模型,并研制了实验样机。仿真和实验结果验证了理论分析的正确性。所提变换器只使用一个功率开关,具有连续的输入电流,同时能够降低开关器件间的电压应力。占空比的工作范围更宽,并且在较低的占空比下可以获得较高的电压增益。输入电流连续是DC-DC变换器的一个理想特性,所提变换器非常适合太阳能、光伏应用。     

A saturable reactor-assisted soft switching PWM DC-DC converter

Owing to the demand to increase the power density of switched-mode power converters, resonant topologies have attracted much attention because of their low switching losses and low EMI. However, they require relatively large resonant components and necessitate high current or voltage ratings at semiconductor devices. This paper describes a new soft-switching PWM full-bridge DC-DC converter which can overcome these drawbacks by utilizing a small saturable reactor. The principles of operation and the steady-state characteristics are illustrated and the role of the saturable reactor is discussed. Moreover, the voltage and current stresses for active and passive components are also presented. To verify the results, experiments were performed with a 350 W, 500 kHz prototype converter. They demonstrated that the converter achieves soft switching in a wide load range with no substantial increase in voltage and current stresses on active and passive components.     

A digital soft-start circuit for buck DC-DC converter

In this paper, a soft-start circuit is present to prevent the large surge current and overshoot voltage to improve the reliability of the DC-DC converter. The proposed structure generates the step-shaped soft-start voltage through 7 bits DAC. Combining with the PWM comparator, the soft-start circuit controls the system duty cycle directly. The mechanism of the soft-start acts as the high clamp function, which eliminates the need of the clamp circuit. A DC-DC buck converter with the proposed soft-start circuit is based on a 0.4 μm BCD process for verification Hspice simulation shows that under the condition with 3.6 V input voltage, 1.8 V output voltage and 600 mA load current, the soft-start is achieved. After 1.2 ms of the soft-start time, the operation turns to stable.     

电压切换回路异常情况的分析

对于双母线系统上所连接的电气元件,在两组母线分开运行时(例如母联断路器断开),为了保证其一次系统和二次系统的电压保持对应,以免发生保护或自动装置误动、拒动,要求保护及自动装置的二次电压回路随同主接线一起切换。用隔离开关两个辅助触点并联后去启动电压切换继电器,利用其触点实现电压回路的自动切换。     

一种新型高电压增益DC-DC变换器研究

随着分布式发电的出现,可再生能源与电池组的结合以及负荷对其的严重依赖,对高效电力电子变换器的需求日益增加.提出一种降低电压应力的高增益DC-DC变换器的新颖结构.该结构是传统Boost变换器两级叠加的结果.当占空比较低时,因为增益与占空比的二次关系,所提供的电压增益很高.此外,该变换器的输入电流连续,所提供的负载接地....