基于UCC2892和LTC3900的开关电源设计

有源钳位正激变换器可以实现零电压开关（ZVS）,降低功率开关损耗;同步整流可以提高低压大电流输出的开关电源的效率。介绍了一种基于有源钳位脉宽调制控制器UCC2892和同步整流控制器LTC3900的正激开关电源设计。     

一种有源钳位的半桥Boost变换器的研究

Boost电路和半桥、全桥电路相结合的电流馈电DC-DC变换器被广泛地使用在UPS、燃料电池等低输入电压、高输出电压的系统中。文中介绍了一种新型的有源钳位电路,在实现有源钳位的同时对所有的开关管实现了ZVS开通,提高了变换器的效率。     

新颖的互补开关驱动电路UC3714／5

随着开关电源向高频、高效、高功率密度方向发展，零电压开关、有源钳位、同步整流等新技术相继问世。与此相适应，美国ＵＮＩＴＲＯＤＥ公司推出了用于软开关、有源钳位和同步整流的互补驱动芯片ＵＣ３７１４／５。本文介绍了该芯片的功能特点与典型应用。     

具有自驱动有源缓冲器的GaN基高效准谐振反激式功率变换器

提出了一种具有自驱动有源缓冲器的GaN基高效准谐振(QR)反激式功率变换器,以解决准谐振反激式功率变换器中开关管关断时电压过高的问题。电路以GaN高电子迁移率晶体管(HEMT)器件为主开关管和同步整流器开关管,自驱动有源缓冲器由钳位电容和有源开关管组成。该变换器在主开关管关断期间将开关管的电压浪涌钳位为恒定电压,由于有源开关管驱动信号由变压器的次级侧电流控制,因此不需要单独的控制电路。为验证所提出的变换器和控制电路的有效性,搭建了一个60 W的AC-DC功率变换器,测试结果表明,主开关管的最大电压浪涌约为450 V,具有高达91.6%的能量转换效率。     

一种新型软开关DC-DC PWM升压变换器设计

为提高转换效率并降低电源开关的电流应力,提出一种基于新型有源缓冲电路的PWM DC-DC升压变换器。该有源缓冲电路使用ZVT—ZCT软开关技术,分别提供了总开关ZVT开启及ZCT闭合、辅助开关ZCS开启及ZCT闭合。消除了总开关额外的电流及电压应力,消除了辅助开关电压应力,且有源缓冲电路的耦合电感降低了电流应力。另外,通过连续将二极管添加到辅助开关电路,防止来自共振电路的输入电流应力进入总开关。实验结果表明,相比传统的PWM变换器,新的DC-DC PWM升压变换器在满负荷时电流应力降低且总体效率能达到98.7%。     

有源钳位正激变换器励磁电感对损耗影响的研究

单端正激有源钳位电路因具有变换效率高、开关管应力低、输入电压范围宽等优点,在低压大电流应用的DC-DC变换器中应用广泛,本文深入研究了正激有源钳位电路在一个开关周期内各工作模态的变换原理,并着重对模态1状态下电源的损耗进行了详细分析,给出了推算过程及求解结果。通过对推算结果的数学分析,得到有源钳位正激电路中变压器励磁电感对损耗影响结果,经MATLAB仿真及实物验证,证实了推理过程。本文所提出的有关励磁电感的观点和设计准则,在设计一个确定匝数比的有源钳位正激变换器时具有借鉴意义。     

编读之窗

问:介绍一下高频开关电源的新技术及其相关产品?(本溪通用自动化控制设备厂朱文胜)中科院计算所严家耀研究员答:降低电源自身的损耗是电源永恒的主题,开关型电源也不例外,每一个进步都环绕着这个主题,使电源做得效率更高,体积更小。开关电源的损耗大部分集中在主开关电路、高频变压器及输出整流电路中,针对这三部分的技术进步简要概述如下:主开关电路由硬开关向软开关电路发展,主要目的是降低功率器件在开通与关闭时的损耗,因变压器漏感,主电流在开关过程中的能量损失。如大家知道的,可采用有源钳位、零电压、零电流开关电路,要求功率大一些…     

700V最高启动电压的PWM控制器

高度集成的电压式PWM控制器NCP1280的有源钳位电路可提供高电压(高达700V)启动,为有源钳位电路提供了控制输出以驱动正向转换器初级MOSFET和辅助MOSFET,也可用带可编程延时二次输出来驱动次级或不对称半桥电路中的同步整流器。其他功能还包括一个700V启动电路、电压前馈、可调最长工作周期控制、高达500KHz的可调振荡器频率、线路欠压和过压监测器、双模式过电流保护和软启动,采用节省空间的SOIC-16封装。与传统的正向转换器拓扑相比,采用NCP1280的有源钳位方案提供了更低的开关和传导损耗,所需的输出感应器更小,降低了一次开关…     

集成的B iCMO S DCöD C 开关电源控制器 输出驱动电器的低功耗设计

为使DC／DC开关电源的功率开关管及时地导通或截止,需要设计专用的输出驱动电路,基于整个开关电源系统低功耗的考虑,开关电源可以采用同步整流的拓扑结构。该拓扑结构需要一个电压自举的输出驱动电路,本文首先提出了一种有自举功能的BiCMOS工艺的输出驱动电路,在此基础上,采用电流源和电流沉串联的方式改进了前面提出的输出驱动电路,通过消除CMOS电路的瞬态短路导通现象,不仅降低了该电路模块的功耗,而且起到了保护的作用,经HSPICE模拟表现,开关电源的输入电压Vin为10V控制器内部电压（VL）为5V,开关频率为200kHz时,改进驱动电路的功耗降低了约11．5％,同时避免了瞬态短路导通现象。     

IGBT驱动有源钳位电路的研究与仿真

绝缘栅双极晶体管关断时会出现电压尖峰,有源钳位电路可以有效抑制这种尖峰电压,但是传统的有源钳位电路损耗大,不利于系统的稳定运行。在分析传统有源钳位电路工作原理和暂态模型的基础上提出一种改进后的有源钳位电路,分析比较两种有源钳位电路的优点,在ORCAD仿真中,对比分析两种有源钳位电路的仿真结果,得出与理论分析一致的结果,证明了改进后有源钳位电路的可行性。     

Analysis and Implementation of a ZVS-PWM Converter With Series-Connected Transformers

This brief presents the analysis, design, and implementation of zero-voltage switching (ZVS) active clamp converter with series-connected transformer. A family of isolated ZVS active clamp converters is introduced. The technique of the adopted ZVS commutation will not increase additional voltage stress of switching devices. In the adopted converter with series-connected transformer, each transformer can be operated as an inductor or a transformer. Therefore, no output inductor is needed. To reduce the voltage stress of the switching device in the conventional forward converter, the active clamp technique is used to recycle the energy stored in the transformer leakage back into the input dc source. Finally, experimental results are presented taken from a laboratory prototype with 100-W rated power, input voltage of 155 V, output voltage of 5 V, and operating at 150 kHz. [All rights reserved Elsevier].     

A high-performance ZVS full-bridge DC-DC 0-50-V/0-10-A power supplywith phase-shift control

This paper presents a high-performance DC-DC switching mode power supply designed to deliver a regulated 0-50 V/0-10 A output. The proposed power supply is based on a modified version of the zero-voltage switching (ZVS) full-bridge (FB) phase-shift DC-DC converter, which incorporates commutation auxiliary inductors to provide ZVS for the entire load range as well as a commutation aid circuit to clamp the output diode voltage. The control strategy is based on two control loops operating in cascade mode. The inner loop maintains a regulated output current, whereas the external voltage loop regulates the output voltage, independently of load and input-voltage changes. In order to obtain a high-reliability converter, the control circuit has been implemented using just two integrated circuits (ICs). The phase-shift regulator UC3875 IC generates the gate drive signal to the MOSFET's. The control loop regulators are implemented using the TL074 IC. A theoretical analysis was conducted, and experimental results were obtained for a 0-50 V/0-10 A power supply operating at 100 kHz     

基于ATMEGA16的开关电源设计与制作

电源广泛应用于各种电子设备及电子电路中。以ATMEGA16单片机为控制核心,设计并制作了具有输出电压步进可调的开关电源。其硬件由整流、滤波、单片机供电电源、DC-DC变换及LED显示组成。经实验测定,输出电压0～9.9V步进0.1V可调,输出电流1.5A,当输出电压9V、输出电流1.5 A时,电压调整率小于0.67%,效率可达78.78%。     

Analysis and implementation of active clamp SEPIC converter with synchronous rectifier

An active clamp SEPIC converter with synchronous rectifier is presented to achieve zero voltage switching (ZVS). The active clamp circuit is adopted in the proposed converter to absorb the energy stored in the leakage inductance of the transformer and limit the peak voltage stress on the switching devices. The resonance during the transition interval between the switching devices will help the power switches to turn on at ZVS. Therefore, the switching losses of switches are effectively reduced. The synchronous rectifier is used at the secondary side of the transformer to further reduce the conduction loss. The principle of operation and the steady-state analysis of the proposed converter are presented. Finally, the experimental results taken from a laboratory prototype with 240 W (12V/20A) rated power are presented to verify the effectiveness of the proposed converter.     

A Three-Phase Current-Fed DC/DC Converter With Active Clamp for Low-DC Renewable Energy Sources

This paper focuses on a new three-phase high power current-fed dc/dc converter with an active clamp. A three-phase dc/dc converter with high efficiency and voltage boosting capability is designed for use in the interface between a low-voltage fuel-cell source and a high-voltage dc bus for inverters. Zero-voltage switching in all active switches is achieved through using a common active clamp branch, and zero current switching in the rectifier diodes is achieved through discontinuous current conduction in the secondary side. Further, the converter is capable of increased power transfer due to its three-phase power configuration, and it reduces the rms current per phase, thus reducing conduction losses. Moreover, a delta-delta connection on the three-phase transformer provides parallel current paths and reduces conduction losses in the transformer windings. An efficiency of above 93% is achieved through both improvements in the switching and through reducing conduction losses. A high voltage ratio is achieved by combining inherent voltage boost characteristics of the current-fed converter and the transformer turns ratio. The proposed converter and three-phase PWM strategy is analyzed, simulated, and implemented in hardware. Experimental results are obtained on a 500-W prototype unit, with all of the design verified and analyzed.      

采用磁集成技术的有源箝位正激变换器设计

针对3.3 V/10 A低压大电流输出、高功率密度电源模块的设计要求,结合有源箝位正激拓扑理论和磁集成技术,提出采用磁集成技术的有源箝位正激变换器;对变换器中的主变压器和输出电感进行集成,得到高效率、高功率密度的有源箝位正激变换器。     

开关电源类负载与交流发电机匹配问题研究

针对开关电源类负载与发电机工作中谐波超标、电压下降等问题,从系统角度阐述了开关电源负载与发电机的匹配工作原理,分析了开关电源谐波的产生和发电机电压下降的原因,对无源、有源及多脉波整流等谐波抑制技术进行了介绍,并给出了系统综合试验方法和试验结果。     

Effect of resonant transition on efficiency of forward converter with active clamp and self-driven SRs

Forward converter with active clamp is a suitable topology for a low output voltage and high output current dc-dc power supply module. The topology can be used in a resonant transition manner to obtain a low voltage over the main switch at turn-on instant. A low voltage can be obtained by adjusting the magnitude of the magnetizing current of the transformer and the delay between the two primary side switches. An increased magnetizing current, however, increases conduction losses in the primary side of the converter and may consume the advantage gained in the switching losses. The converter can also be easily used for self-driven synchronous rectification. However, pursue for low switching losses for the primary side switch may deteriorate performance of the self-driven synchronous rectifiers, particularly at high loads. This paper presents a study of the applicability and advantage of the use of the resonant transition in Forward with active clamp and self-driven synchronous rectifiers. The emphasis is on the comparison of the achieved efficiency with different voltage levels over the primary switch prior to turning on. Measurement results show that, at low loads, a reduced voltage level improves the efficiency but, on the other hand, at high loads the advantage is not so significant, or it may be totally lost, mainly due to the increased losses of the self-driven synchronous rectifiers. The paper includes discussion on the effect of the magnetizing inductance on the efficiency of the converter and the optimal voltage level at which the primary switch should be turned on. Measurement results from a 3.4-V 30-A prototype converter are included.     

一种DC-DC升压型开关电源的低压启动方案

设计了一种DC-DC升压型开关电源的低压启动电路,该电路采用两个在不同电源电压范围内工作频率较稳定的振荡器电路,利用电压检测模块进行合理的切换,解决了低输入电压下电路无法正常工作的问题,并在0.5μm CMOS工艺库（VthN=0.72 V,VthP=-0.97 V）下仿真。仿真结果表明,在0.8 V低输入电压时,通过此升压型开关电源,可以将VDD升高至3.3 V。