多相交错并联Boost功率因数校正器的研究

针对开关电源在传统的Boost功率因数校正电路中有着明显的开关损耗,使得电路具有较高成本和低效率。文中在传统单相Boost变换器的基础上,采纳多通道交错并联技术来进行有源功率因数校正的主电路拓扑。以三相交错并联Boost变换器为例,分析其工作过程,并通过仿真实验证明了多相交错并联Boost PFC变换器具有减小输入电流纹波和输入电感值,以及提高变换器的效率等优点。     

Boost变换电路的损耗分析

分析了开关器件、电感在硬开关Boost PFC电路中的损耗,并对Boost PFC变换器电路的开关损耗进行了计算,给出了其功率损耗的计算方法.同时通过对有源功率因数校正集成电路UC3854实现Sever Computer的600W开关电源的分析计算,用实验验证了Boost PFC电路功率损耗计算方法的正确性.     

峰值电流型PFC Boost变换器斜坡补偿方法研究

PFC Boost电路中由于输入电压的时变性造成输入电流在过零附近产生分岔现象,本文针对该现象,以电流连续模式（CCM）下峰值电流型PFC Boost变换器的精确时变模型为基础,研究了抑制分岔的斜坡补偿方法,通过SIMULINK仿真验证,表明输入电流分岔现象得到消除,接近输入电压波形,改善了PFC Boost变换器的性能。     

基于FPGA的交错并联PFC的研究

随着电力设备的功率等级不断提高,使得传统Boost PFC变换器存在较大的输入纹波、转换效率较低等缺点。因此,这里将交错并联拓扑结构引入到Boost PFC变换器中,在平均电流控制策略的基础上建立离散化数字控制模型,选择现场可编程逻辑门阵列(FPGA)控制器来实现交错并联Boost PFC电路的数字控制。仿真结果表明,该设计有效优化了电源的性能,使得电源中的谐波电流含量减少,大大提高了开关电源的功率因数。     

单相两级有源功率因数校正变换器的研究

文中对两级有源功率因数校正变换器进行研究,设计了一台510W两级式开关电源。该电源前级采用平均电流控制的Boost型PFC电路,实现功率因数校正;后级采用不对称半桥型DC／DC变换器,实现开关管的零电压开关。控制电路采用PFC／PWM复合控制芯片ML4824,缩小电源体积。通过实验证实该开关电源具有高功率因数与高效率的特点。     

PFC Boost变换器次谐波振荡抑制方法研究

峰值电流型功率因数校正升压(PFC Boost)变换器运行时会产生次谐波振荡与混沌现象,影响电路的稳定运行,通常采用固定斜坡补偿或分段固定斜坡方法进行抑制,但是固定斜坡补偿方法来自于DC-DC Boost变换器,用于PFC Boost变换器具有不可克服的缺陷。该文提出了一种能够彻底消除电路中次谐波振荡的动态斜坡补偿方法,并以110 V/200 W的PFC Boost变换器为研究对象,利用Matlab/Simulink进行了仿真和验证分析。结果表明,所提出的动态斜坡补偿方法可实现次谐波振荡抑制和单位功率因数校正的双重功能。     

无直流电压传感器的单相APFC变换器

文章对一种只检测交流输入电压而不需要检测输出直流电压的简化单相PFC变换器进行了理论分析和研究。在构建控制电路时,不需要常规PFC变换器中的输出电压传感器和输入电流传感器。PFC变换器的主电路为整流电路的直流侧接一级Boost电路。在控制电路中,使用电感L、等效负载电阻Rd等电路参数产生正弦电流波形基准,输出电压直接由控制量Kd(=Ed/Ea)来调节。通过控制,可以得到恒定的直流输出电压和与交流输入电压同相位的正弦电流波形。仿真结果证明了该变换器的可行性。     

一种等离子显示系统专用电源

设计了一个用于多屏拼接等离子显示系统的专用电源。该电源采用两级变换,前级AC/DC变换采用Boost型有源功率因数校正电路,后级变换器对于不同的回路根据功率的大小分别采用全桥变换器和单端反激变换器。对传统Boost型功率因数校正电路提出了一点改进,有效抑制了传统Boost型功率因数校正电路中大功率时开关管开通时二极管上瞬时大电流。后级变换器中主回路采用一种次级无源箝位ZVZCS全桥变换器,适宜大功率的输出且有效降低了开关损耗。     

基于RC滤波融合二次方运算的Boost-PFC变换器研究

为减少开关变换器电流谐波对电网的污染,降低变换器输出电压超调,提高变换器的稳定性,以单相Boost型拓扑结构功率因数校正（PFC）变换器为研究对象,对变换器原理及其工作模态等效电路进行分析。基于平均电流控制方式,提出一种RC滤波融合二次方运算的输入电压采样方案,在输入电压采样支路增加一个RC滤波电路和一个二次方运算电路,更精确地对输入电压进行采样,从而减少变换器电流谐波、提高变换器稳定性。在Matlab/Simulink软件中搭建仿真电路,同时设计了实验样机进行验证。结果表明,与传统功率因数校正电路相比,该方案有效减少了变换器电流谐波,抑制了变换器输出电压尖峰,同时提高了变换器的输出稳定性。     

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。     

新型三相单开关功率因数校正器的研究

为解决传统三相单开关功率因数校正器输入电流谐波较大的问题,设计了一种新型拓扑结构的三相单开关升压型PFC(Power Factor Correction)电路。通过在Boost电感和整流桥之间插入合适电容构成二阶滤波器,虽然控制算法不变,但可以在保证功率因数不变的前提下优化输入电流THD（Total Harmonic Distortion）。基于对电路原理的简要分析,建立Matlab仿真模型,再以TMS320F28335为控制核心,搭建Boost PFC 变换器的实验平台。仿真和实验均表明该方案可行,实验电路测试的输入电流THD值小于10%,具有实际应用价值。     

The bang-bang hysteresis current waveshaping control technique used to implement a high power factor power supply

This work reports the operation and development of a high power factor power supply that operates at high switching frequency. An optimum power factor correction is obtained using an ac-dc boost converter associated to a nondissipative snubber as a pre-regulator circuit, which presents reduced commutation losses. The same nondissipative snubber is associated to a Forward converter and then used as a dc-dc stage. The proposed switched mode power supply presents high power factor (0.998), high efficiency (91%), low harmonic content (current and voltage total harmonic distortion rates equal to 2.84% and 2.83%, respectively), and also satisfactory regulation. The converter has been theoretically analyzed, designed, simulated and implemented, where experimental results show that soft commutation in all switches is achieved.     

Slow-Scale Instability of Single-Stage Power-Factor-Correction Power Supplies

This paper reports slow-scale instability in a single-stage power-factor-correction (PFC) power supply, which is a popular design solution for low power applications. The circuit employs a cascade configuration of a boost converter and a forward converter, which share an active switch and operate in discontinuous-conduction mode (DCM), to provide input PFC and tight output regulation. Main results are given by "exact" cycle-by-cycle circuit simulations. The effect of the slow-scale instability on the attainable power factor is illustrated in terms of total harmonic distortion which can be found by taking the fast Fourier transform of the input current. The slow-scale instability usually manifests itself as local oscillations within a line cycle. Based on the critical condition of DCM for the buck converter, the underlying mechanism of such instability is further investigated. It has been found that border collision is the underlying cause of the phenomenon. Moreover, it has been shown that the border collision observed here is effectively a nonsmooth Neimark-Sacker bifurcation. Finally, experimental results are presented for verification purposes.     

DC voltage sensorless single-phase PFC converter

We propose a simple DC voltage sensorless single phase PFC converter by detecting an AC line voltage waveform. Both DC voltage and AC current sensors used in the conventional PFC converter are not required to construct the control system. The conventional converter circuit with a boost chopper circuit in the DC side from a rectifier circuit is used as the main PFC converter circuit. In the control system, the circuit parameters such as a series inductance L and equivalent load resistance value R/sub d/ are used to generate the sinusoidal current waveform. The DC voltage is directly controlled by the command input signal k/sub d/(=E/sub d//E/sub a/) for the boost chopper circuit. The DC voltage regulation is small because of the feed forward control for the AC line voltage E/sub a/ and no dependence of the circuit parameters. The sinusoidal current waveform in phase with the AC line voltage can be obtained. The feasibility of the proposed control system is verified by some simulation and experimental results.     

Duty-ratio feedforward for digitally controlled boost PFC converters

When a "classical" current control scheme is applied, the line current of a boost power-factor-correction (PFC) converter leads the line voltage, resulting in a nonunity fundamental displacement power factor and in important zero-crossing distortion in applications with a high line frequency (e.g., 400-Hz power systems on commercial aircraft). To resolve this problem, a current-control scheme is proposed using duty-ratio feedforward. In this paper, the input impedance of the boost PFC converter for both the classical current-loop controller and the controller using duty-ratio feedforward are derived theoretically. A comparison reveals the advantages of the proposed control scheme: a low total harmonic distortion of the line current, a resistive input impedance, virtually no zero-crossing distortion, and a fundamental displacement power factor close to unity. The theoretical results obtained are verified using an experimental setup of a digitally controlled boost PFC converter.     

基于前馈电流控制斜坡补偿的Boost功率因数校正零交越失真研究

该文提出了一种前馈电流控制的斜坡补偿方法,将该方法引入到临界导通Boost 功率因数校正(PFC)转换器的设计中,以减小零交越失真问题,改善谐波电流和频率对系统的限制。基于临界导通Boost PFC转换器的拓扑结构,理论分析了前馈电流控制斜坡补偿技术对脉冲宽度调制(PWM)信号占空比的调制作用,推导出补偿斜率与输入线电压的关系式,迫使线电压零交越点附近的电流跟随电压变化。仿真和测试结果表明,该方法可有效抑制零交越失真现象,提高系统的动态性能,尤其在高频及轻负载情况下。测得Boost PFC转换器的总谐波失真(THD)仅为3.8%,功率因数0.988,负载调整率3%,线性调整率小于1%,效率达到97.3%。有效芯片面积为1.611.52 mm2。     

高功率因数开关电源的研究

普通开关电源采用电容输入型二级管整流电路,使输入电流呈脉冲波形,造成功率因数很低。如何提高开关电源的功率因数已经成为电源设计工程师的首要任务。文章给出了高功率因数高频开关电源系统的总体设计方案,并在此基础上,对各电路的工作过程进行了简单介绍。     

Stabilizing Technique for AC–DC Boost PFC Converter Based on Time Delay Feedback

It is well known that the ac–dc power factor correction (PFC) boost preregulator can present instability at the line frequency. This nonlinear phenomenon can jeopardize the system performances by increasing the total harmonic distortion and decreasing the power factor. In this brief, a new stabilizing technique is applied using time delay feedback when the system exhibits slow-scale instability under a traditional controller. First, the technique is applied to the averaged model. The results are then validated by numerical simulations using power simulator package. An analytical expression for the stability domain is also provided. It is proven that the proposed technique introduces many advantages to the most and widely used average current mode control through widening the stability region of the PFC converter. Moreover, this technique can also bring the same advantages to other existing commercial control methods for boost and other PFC topologies.