有源功率因素校正电路控制方法的研究

针对传统的Boost ZVT-PWM有源功率因数校正电路中辅助开关管为硬开关工作状态下开关关断损耗大、系统效率低的缺点,提出了在辅助开关管电路中增加无损耗的吸收电路来实现辅助开关管的软关断。改进型Boost ZVT-PWM功率因数校正电路使整个电路的开关管都处在软开关状态,提高了系统的效率。仿真结果验证理论分析的正确性。     

一种高效单级变换式LED驱动电源设计

论文介绍了一种高效单级功率因数校正LED驱动电源。该电源采用SEPIC拓扑在临界导通模式下实现了功率因数校正和对LED灯的恒流驱动,电路采用单级PFC结构简化了电路结构,采用零电压开关技术降低了开关管的开关损耗。实验结果表明,该电源功率因数高、损耗小、输出稳定,可以高效率驱动LED灯工作。     

一种有源功率因数校正电路及控制方法的设计

从开关变换器的基本拓扑结构出发,寻找简单和方便的控制方式。根据正向输出的Buck—Boost变换器工作的基本原理,提出了一种新的功率因数校正电路结构,给出了相应的控制方法,并对其进行了仿真。该电路能够利用电压跟随的方式实现PFC。由于该电路能够实现降压输出,因此降低了对所有功率开关管的耐压要求,有利于提高变换器的转换效率并降低成本。     

三相Boost功率因数校正电路分析与实验研究

对功率因数校正技术的现状作了介绍,提出了一种新型的软开关三相 Boost功率因数校正电路,并分析了其工作原理,给出了实验.     

一种新型的低成本高性能在线式UPS

提出了一种新型的低成本单相在线不间断电源(UPS)。该系统包括具有功率因数校正(PFC)功能的整流/升压转换器和连接到DC-Link总线的两桥臂逆变器,电池组通过一个非常简单的系统可直接连接到DC-Link总线。采用6开关管的架构,相对于传统的8开关管全桥拓扑结构的系统降低了成本。即使在非线性负载下,该系统仍具有功率密度高和高品质输出电压的特点。最后详细描述了电路操作、分析以及模拟和实验结果。     

基于单周期控制的机载三相高功率因数整流器研究

飞机对机载设备的用电特性要求越来越严格,特别是对三相电源的输入功率因数和电流谐波有着严格的要求,此外在电磁兼容试验中对输入电流谐波含量的要求也很高。研究了机载三相三开关三电平整流器,将其等效为三个单相功率因数校正(PFC)电路,分别采用英飞凌单周期PFC控制芯片ICE3PCS02实现了三相功率因数校正电路。仿真与实验结果表明该电路在三相功率因数校正方面有着良好的效果,在中小功率机载雷达电源上具有广泛应用前景。     

三相Boost功率因数校正电路分析与实验研究

对功率因数校正技术的现状作了介绍,提出了一种新型的软开关三相Boost功率因数校正电路,并分析了其工作原理,给出了实验。     

高功率因数双开关升压整流器的单周期控制方法

研究了一种高功率因数的双开关升压整流器的单周期控制方法。在该整流器中。二极管整流电路和功率因数校正环节结合在一起。减少了导通损耗。具有效率高，结构简单等特点。但是由于升压电感在交流侧，电流和电压检测不是很方便。为此，引进单周期控制技术。它不需要检测交流输入电压。而且对输入电流的检测也相对简单。同时单周期控制电路具有简单可靠、响应快、成本低、易于实现等特点。文中较为详细地分析了单周期控制双开关升压整流器的工作原理和实现方式，最后在PSpice中进行了仿真验证。     

一种新型单级PFC研究

提出了一种新型单级功率因数校正AC/DC变换器,给出了电路的拓扑结构,分析研究了这种变换器的各种工作模式.实验结果表明,这种变换器具有电路拓扑简单,功率密度高,功率因数高,成本低等优点.     

基于UC3854B的高功率因数电源的研制

文章介绍了一种基于UC3854B控制的高功率因数电源的研制方案,给出了电源主电路结构及原理,简要推导了采用Boost电路实现功率因数校正时开关管占空比的数学方程,重点介绍了控制电路中UC3854B外围电路的设计及元器件参数的选取。实验结果表明,基于UC3854B的Boost PFC开关电源具有较好的功率因数校正功能,控制效果较好。     

功率MOS管R_(DS(on))负温度系数对负载开关设计的影响

介绍了功率MOS管导通电阻的正温度系数和负温度系数的双重特性以及相对应的V_(CS)的转折电压,负载开关电路通过延长米勒平台的时间来限制输入浪涌电流的工作特点。分析了由于米勒平台工作于负温度系数区域,产生的开关损耗导致局部热不平衡从而形成局部热点的原因。实验结果表明,减小输出电容、提高功率MOS管的散热能力,可以提高系统的可靠性。     

High‐performance high‐efficiency LED‐backlight driving system for LCD panels

Abstract— A high‐performance high‐efficiency LED‐backlight driving system for liquid‐crystal‐display panels is presented. The proposed LED‐backlight driving system is composed of a high‐efficiency DC‐DC converter capable of operating over a universal AC input voltage (75–265 V) and a high‐performance LED‐backlight sector‐dimming controller. The high efficiency of the system is achieved by using an asymmetrical half‐bridge DC‐DC converter that utilizes a new voltage‐driven synchronous rectifier and an LED‐backlight sector‐dimming controller. This controller regulates current using lossless power semiconductor switches (MOSFETs). The power semiconductor switches of the proposed DC‐DC converter, including the synchronous rectifier switch, operate with zero voltage, achieving high efficiency and low switch voltage stress using the asymmetrical‐PWM and synchronous rectifier techniques. To achieve high performance, the proposed driving system performs the sector dimming and the current regulation using low‐cost microcontrollers and MOSFET switching, resulting in high contrast and brightness. A100‐W laboratory prototype was built and tested. The experimental results verify the feasibility of the proposed system.     

Modeling and simulation of a new Bridgeless SEPIC power factor correction circuit

A new Bridgeless PFC circuit based on Single-Ended Primary Inductance Converter (SEPIC) is proposed in this paper. The new topology has less component count and less conducted component during each mode of operation within one switching period. The small-signal and steady-state model of the circuit operated in Discontinuous Conduction Mode (DCM) is derived using the Current Injected Equivalent Circuit Approach (CIECA). The large-signal model based on state-space and switch model are also developed to verify the large-signal behavior. The simulation results of the proposed converter show that the output voltage of the proposed converter is successfully regulated to its desired value while the input current regulation is inherent.     

VHF宽带E类高效率功率放大器设计

使用ADS(Advanced Design System)软件仿真设计了基于28-V MOSFET器件的VHF频段30 MHz～80 MHz E类开关模式高效率功率放大器。输入端使用了宽带匹配,输出端通过开关改变后端的匹配电路和滤波器。电路实测:30 MHz～80 MHz输出功率3.2 W～7.1 W,效率从30 MHz的71.4%到80MHz的52.5%,并且具有优良的调幅线性度,可以将其应用到EER发射机。     

Efficient Supply Current Control Strategies for Bridgeless Interleaved AC-DC Converter

This paper presents an efficient supply current wave shaping technique for bridgeless interleaved Single Ended Primary Inductor Converter (SEPIC). The SEPIC converter converts an Alternating Current (AC) to Direct Current (DC) with the boost converter. Power Factor Correction (PFC) is progressively significant to achieve high energy efficiency. The overall system efficiency can be increased as the bridgeless topology has less conduction losses from rectifying bridges. Also, the bridgeless and interleaved techniques are incorporated in this study to achieve better performance. The performance of the system is analyzed on both current control and sensor-less techniques. Different controllers such as Proportional Integral (PI) control, peak current control, Non-Linear Carrier (NLC) control, and sensor-less current control are integrated. All the above controllers are implemented using MATrix LABoratory (MATLAB)/SIMULINK. The performance parameter, namely Power Factor (PF), Total Harmonic Distortion (THD), is computed for both open loop and closed loop condition. The sensor-less current control method is implemented using the DsPIC30F2010 controller. The circuit performance is also verified from the simulation and hardware results. The proposed controller has inbuilt Analog-to-Digital Converter (ADC), Digital-to-Analog Converter (DAC), Pulse Width Modulation (PWM) generator, and provides fast responses.     

UC3724/3725功率MOSFET驱动电路芯片组的应用

高电压,大电流N沟道MOSFET越来越广泛地应用于大功率的电力电子设备中。UNITRODE公司的UC3724／UC3725芯片缓 通过使用一种独特的调制技术－－通过小型的高频脉冲变压器同时传输信号和功率,实现简单高效的带有电气隔离的MOSFET驱动电路。此电路具有可工作在任意占空比下、实用性强、电路结构简单、响应速度快、输出阻抗小等特点。     

Principle of designing slope compensation in PFC Boost converter

Due to wide input fluctuation with line frequency of 50 Hz, power-factor-correction (PFC) Boost converters tend to exhibit fast-scale instability over time domain. The traditional remedy is to impose slope compensation so as to weaken or eliminate this instability. A theoretical principle on the implementation of slope compensation signal is still lacking. Empirical design will induce over compensation frequently, resulting in a large decrease of power factor. In order to tackle this issue, by constructing the discrete-time iterative map of the PFC Boost converter from the viewpoint of bifurcation control theory of nonlinear systems, consequently, the criterion of critical stability for the PFC circuit can be established. Based on this stability criterion, appropriate design of slope compensation can be achieved. Our work indicates that 3 main circuit parameters (i.e. switching cycle, output reference voltage and inductor) determine the effective amplitude design of the slope compensation signal. The results, validated by a large quantity of analytical and numerical studies, show that appropriate slope compensation can be effective in weakening (or controlling) fast-scale bifurcation while maintaining a rather high input power factor.     

两种高功率因数开关电源设计的比较

针对传统开关电源因输入电路采用不可控二极管或相控晶闸管整流而存在输入电流谐波含量大、功率因数低的问题,提出了两种高功率因数开关电源的设计方案,分析了采用APFC技术和PWM整流技术来提高开关电源功率因数的原理,并采用Matlab7.6仿真软件对单相全桥电压型PWM整流电路和APFC电路进行了仿真。仿真结果表明,基于PWM整流技术的开关电源能更好地实现高功率因数,减少谐波电流。