高输入电压单端反激式开关电源设计关键问题

讨论了高输入电压情况下单端反激式开关电源设计中的关键问题,如变压器设计中的匝数较多、漏感引起的尖峰电压及缓冲回路设计及器件选择等问题,并提出了相应的解决策略。提供了详细的实验波形,充分验证了方案的正确性,为后续开发者提供了参考。     

Analysis and implementation of a new zero current switching flyback inverter

In this paper, a novel zero current switching (ZCS) flyback inverter in discontinuous conduction mode (DCM) is proposed. In the proposed flyback inverter, the ZCS for the primary switch is achieved by adding a simple auxiliary circuit to the conventional flyback inverter. Also, the auxiliary switch is turned on and turned off at ZCS condition. Therefore, the switching losses of the switches are negligible, which increases the efficiency and allows higher switching frequency and more compact design. The resonant auxiliary cell is activated only in short transition times that makes its conduction losses negligible. Furthermore, the voltage overshoot of the main switch is limited during the turn-off process, which allows utilization of lower voltage metal-oxide semiconductor field-effect transistors (MOSFETs) with low conduction losses and low cost. The detailed operation of the flyback inverter with auxiliary circuit and design considerations are presented. Simulation and experimental results are presented to verify the performance of the proposed inverter.     

Dynamics and Operation-State Estimation of Current-Mode Controlled Flyback Converter

By utilizing total magnetic flux φ of the primary and secondary windings of the flyback transformer as a state variable,the discrete-time model of current-mode controlled flyback converter is established,upon which the bifurcation behaviors of the converter are analyzed and two boundary classification equations of the orbit state shifting are obtained.The operation-state regions of the current-mode controlled flyback converter are well classified by two boundary classification equations.The theoretical analysis results are verified by power electronics simulator(PSIM).The estimation of operation-state regions for the flyback converter is useful for the design of circuit parameters,stability control of chaos,and chaos-based applications.     

反激式开关电源用UC384x芯片的斜坡补偿

阐述了斜坡补偿的基本原理,系统地分析了反激式开关电源用UC384x芯片现有的斜坡补偿方式,并在此基础上提出单电容补偿方式。通过实验验证了方案的可行性。     

An active‐clamping zero‐voltage‐switching flyback converter with integrated transformer

This paper proposes an active‐clamping flyback converter using an integrated transformer. The proposed converter is composed of two active‐clamp flyback converters. The presented converter can balance the total load current between secondary sides of two transformers so that the rectifier diode conduction loss is reduced. Also, the main switch of one converter is the auxiliary switch for the other converter, so that only two switches are required and both can achieve zero‐voltage‐switching operation. The two transformers are integrated into one magnetic core; therefore, the volume and copper loss of transformer can be reduced. Detailed analysis and design of this integrated magnetic active‐clamping flyback converter are described. Experimental results are recorded for a prototype converter with an AC input voltage ranging from 85 to 135 V, an output voltage of 24 V and an output current of 5 A, operating at a switching frequency of 100 kHz. Copyright © 2014 John Wiley & Sons, Ltd.     

交错并联反激式三电平逆变器

传统Flyback逆变器应用在高电压、大功率场合时常会存在电压应力过大等问题。为此,在传统反激逆变器拓扑中引入二极管箝位多电平技术,提出了一种交错并联反激式三电平逆变器。分析了该拓扑的工作原理,推导了输入与输出的关系,并分析了该逆变器的外特性,给出了电路中主要参数的计算方法。仿真和实验结果验证了所提拓扑的可行性。     

一种软开关反激光伏并网逆变器的分析与设计

详细分析了一种反激光伏并网逆变器软开关电路的拓扑结构和工作过程。该软开关电路利用反激变压器的漏感与缓冲电容,在功率管开关过程中进行谐振,实现了漏感能量吸收再利用。在软开关电路中设计了调整电感,使谐振周期和谐振能量能够实现功率管漏源极电压箝位。在提高变换效率的同时降低了开关管关断电压尖峰。并据此设计了一台原理样机,实现了功率管的零电压开启,改善了逆变器的电磁兼容(EMI)特性,有效改善了并网电流波形质量。     

A cost‐effective PWM dimming method for LED lighting applications

This paper presents a novel cost‐effective pulse‐width‐modulation (PWM) dimming method for light‐emitting diode (LED) lighting applications. High efficiency, high power factor, circuit simplicity, and low cost can be achieved by a Flyback power factor correction converter with the studied adaptive PWM dimming method. The operation principles and design considerations of the proposed LED dimming method are analyzed and discussed. A 45 W laboratory prototype has been built and tested to verify the feasibility of the proposed scheme. Copyright © 2013 John Wiley & Sons, Ltd.     

高精度可调式单端反激开关电源设计

介绍了一款采用三端高频单片开关电源芯片TOP 223Y,配合由TL431、PC817A组成的反馈系统完成多路输出的单端反激开关电源,在此基础上加入LM2596和可调电位器进行改进,实现输出反馈权值可调、输出可调的新型高精度开关电源。实验结果表明,该开关电源效率高、纹波小、精度高、稳定性强。     

一种基于NCP1014的反激式开关电源设计研究

介绍了反激式开关电源的原理,给出了基于NCP1014芯片的电源设计方案,高频变压器初次级匝数以及临界电感计算方法,研究了反激式开关电源电压质量与MOSFET开断的关系,给出了解决方案。实验结果表明,该设计方案具有电压及负载调整率好,效率高,电压纹波小等优越性能。