Boost PFC变换器数字控制研究

单周期功率因数校正(Power Factor Correction,PFC)技术无需采样输入电压和乘法器,具有动态响应速度快、抗电源扰动能力强的特点。在分析单周期控制Boost PFC变换器工作原理的基础上,给出了单周期PFC技术的数字实现方案以及控制方程。基于动态逻辑库(Dynamic Link Library,DLL)模块建立数字控制PFC系统模型并应用Psim软件完成仿真验证,再以TMS320F28027为控制核心,搭建Boost PFC变换器的实验平台进行实验。仿真和实验均表明数字控制方案可以较好地实现PFC,证明了所提方案的优良性能。实验电路测试获得的功率因数达到0.99以上,输入电流THD值小于11%。     

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。     

无桥Boost PFC技术的研究

与传统Boost PFC电路相比,无桥Boost PFC电路能提高整机效率,特别适用于中大功率电路中.实验基于无桥Boost PFC拓扑,控制电路分别采用“平均电流控制“技术的芯片L4981和“单周期控制“技术的芯片IR1150,研制出一台1500W的实验样机,并对两种控制电路进行了详细的对比分析.实验结果证明两种控制方法均能达到较好的功率因数校正效果,功率因数大于0.97,THD值小于10%.     

单周期控制的无桥APFC电路仿真研究

为达到功率因数校正(PFC)的目的;采用单周期的控制方法,来控制开关变换器的开关管使交流输入电流波形跟踪交流输入电压波形,从而实现交流电流波形正弦化。应用Matlab软件对设计的电路进行仿真实验,实验结果表明单周期控制的无桥功率因数校正电路具有很好的校正效果,而且该电路具有开关器件少,功耗低,电路体积小和控制电路简单的优点。     

三相功率因数校正电路拓扑结构的研究

介绍了三相功率因数校正电路几种主要的拓扑结构——三相单开关功率因数校正电路、三相两开关PFC电路、三相三开关PFC电路、三相四开关PFC电路等;并分析了每种拓扑结构的特性、优点以及缺点,应用MATLAB软件对其中部分电路做了仿真。     

基于CRM Boost PFC的低功耗低THD前馈补偿设计研究

为了获得低功耗低总谐波失真(THD)特性,基于CSMC 0.5μm BCD 工艺,讨论并分析了一种新颖的临界导通Boost PFC 转换器。通过引入前馈补偿设计增加了PWM占空比,在输入线电压零交越点附近提供了更多的转换能量,从而调整了PFC转换器的电感电流,补偿了系统环路增益随交流线电压的变化。理论和实验结果均表明,所提出的基于前馈补偿单元的PFC转换器具有较好的功率因数和THD性能,适用于低功耗低THD设计应用。测得Boost PFC转换器的THD为4.5%,开启电流为54μA,稳定工作电流为3.85mA,功率因数0.998,效率达到95.2%。     

三相三开关部分有源功率因数校正电路的研究

三相交流电源供电的较大功率变频空调日益得到广泛应用,带来了三相整流器的功率校F问题。在简要分析三相单开关部分有源PFC的基础上,根据三相三线制、三相四线制供电方式的不同,提出了两种结合有源PFC技术和无源PFC技术的Buck型混合三相有源部分PFC方案,在对其工作原理进行简要分析和仿真分析的基础上,进行了实验研究,所得结果验证了所提出的三相部分PFC具有电压与电流应力小、效率高、功率因数高、直流平均电压较高的特点,各种负载下交流输入侧的各次谐波电流均满足IEC61000-3-2标准,中等负载以上时输入功率因数高达0.98。     

基于R2A20114SP的功率因数校正电路

介绍一种交互式新型的功率因数校正电路(PFC),该电路以R2A20114SP芯片为控制核心,采用Boost升压电路,整合了临界导通模式(CRM)交错PFC控制技术,同时根据芯片特点设计了匹配的MOSFET驱动电路.实验表明:电路保证了输入电流波形为正弦,输入电流谐波足以满足IEC100032的要求;PFC级的电流能自动跟随输入电压,提高了功率因数(PF)值.     

软开关APFC倍频感应加热电源的研究

针对倍频感应加热电源整流器的非线性特性引起网侧电流畸变,功率因数低等问题,采用一种新型的软开关Boost电路取代传统LC滤波环节进行功率因数校正。整个电源系统采用DSP＋CPLD实现了CCM模式下的平均电流PFC控制和倍频逆变模块的分时一移相控制策略。仿真与试验结果实现了输入侧单位功率因数,升压电路的开关管在高频开关状态下实现ZCS开启与ZVS关断,开关损耗大大降低。     

基于谐波注入的三相功率因数校正设计技术

三相单开关功率因数校正器在硬开关下,由于其谐波失真率(THD)较大而使功率等级受到限制。通过谐波注入技术调制占空比,在不连续导通模式(DCM)下对输入电流进行功率因数校正(PFC),获得了极佳的性能。这种方法可以使校正器的THD减小,以及在满足强制谐波标准(如IEC61000-3-2)下达到更大的功率等级。采用该方法,已经做出1 kW实际样机。     

Resonant-boost-input three-phase power factor corrector

This paper presents a novel three-phase power factor corrector (PFC) circuit which uses two power switches working in zero-voltage-switching (ZVS) condition. The two switches along with a high-frequency inductor constitute a high-frequency current source which is responsible for the energy transfer in the circuit. The input current is partly continuous and partly discontinuous. The total harmonic distortion (THD) in the input current has a low value of 4.5%, and the output DC voltage is very close to the peak line voltage. The operation of the converter is explained by identifying the different switching modes, and the simulation and experimental waveforms are presented     

基于BOOSt结构下不连续导电模式的PFC电路

采用现代高频功率变换技术的有源功率因数校正（Power Factor Corrector,PFC)技术是解决高频开关变换器谐波污染的有效手段。与传统的PFC电路相比，有源PFC电路的输入电流接近正弦波且与输与电压同相位，能有效抑制电流波形畸变和谐波，因此避免了对同一电网设施的干扰。在PFC电路中，Boost变换器是研究和应用得最多的一种变换器。本文着重分析了Boost电路在不连续导电模式状态下，PFC电路的临界条件，对实际电路结构的设计有很好的指导意义。     

Single-stage three-phase boost power factor correction circuit for AC–DC converter

This article presents a single-stage three-phase power factor correction (PFC) circuit for AC-to-DC converter using a single-switch boost regulator, leading to improve the input power factor (PF), reducing the input current harmonics and decreasing the number of required active switches. A novel PFC control strategy which is characterised as a simple and low-cost control circuit was adopted, for achieving a good dynamic performance, unity input PF, and minimising the harmonic contents of the input current, at which it can be applied to low/medium power converters. A detailed analytical, simulation and experimental studies were therefore conducted. The effectiveness of the proposed controller algorithm is validated by the simulation results, which were carried out using MATLAB/SIMULINK environment. The proposed system is built and tested in the laboratory using DSP-DS1104 digital control board for an inductive load. The results revealed that the total harmonic distortion in the supply current was very low. Finally, a good agreement between simulation and experimental results was achieved.     

Characterization of single-stage three-phasepower-factor-correction circuit using modular single-phase PWM DC-to-DCconverters

The complete DC characteristics of three-phase modular power-factor-correction (PFC) converters using single-phase pulsewidth modulation (PWM) DC-to-DC converter modules for high-power applications are studied. Using circuit averaging, the converter input and output quantities are determined numerically. Both the continuous and discontinuous output current modes of operation (CCM and DCM) are studied in detail. Near-unity power factor can be achieved with the converter modules operating in the DCM. An averaged model was used to study and determine the boundaries between DCM and CCM over the full period of the three-phase input voltage. It is found that high power factor is inherent in the converter system provided that the converters are operated in the DCM and the voltage conversion ratio is selected properly. The criteria for obtaining high power factor are analyzed and the optimal circuit parameters are determined to obtain the best achievable power factor. Both simulations and experimental results from a 1.5-kW prototype using full-bridge converter modules have confirmed the analysis     

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.     

Novel current transducer in a single-phase active power factorcorrection system

In line-fed converters implementing power factor correction, the current shaping process requires input current sensing, commonly obtained using dedicated power components as shunts or current transformers. This work presents a current sensing circuit applied to active power factor correction with boost topology, which does not use the previous components. The sensing element is an inductor placed in the input filter, needed to comply with electromagnetic emission standards. The operating principle of the proposed sensing circuit is then extensively discussed, and analytical formulation of the frequency response is given for real conditions. The influence of transducer error on the performance of the power factor correction (PFC) system is also analyzed. Theoretical analysis shows that a system with a low total harmonic distortion (THD) can be achieved, and this is confirmed by experiments on a laboratory prototype     

A digital power factor correction (PFC) control strategy optimized for DSP

A predictive algorithm for digital control power factor correction (PFC) is presented in this paper. Based on this algorithm, all of the duty cycles required to achieve unity power factor in one half line period are calculated in advance by digital signal processors (DSP). A boost converter controlled by these precalculated duty cycles can achieve sinusoidal current waveform. One main advantage is that the digital control PFC implementation based on this control strategy can operate at a high switching frequency which is not directly dependent on the processing speed of DSP. Input voltage feed-forward compensation makes the output voltage insensitive to the input voltage variation and guarantees sinusoidal input current even if the input voltage is distorted. A prototype of boost PFC controlled by a DSP evaluation board was set up to implement the proposed predictive control strategy. Both the simulation and experimental results show that the proposed predictive strategy for PFC achieves near unity power factor.     

Operating a three-phase diode rectifier with a low-input currentdistortion using a series-connected dual boost converter

This paper describes a technique for shaping the input current to a three-phase diode rectifier using a two-switch series-connected dual boost converter and a three-phase bidirectional switch circuit. Circuits are described for generating a single voltage DC output, “single DC-rail”, or a dual output DC voltage using center-tapped capacitors, “split DC-rail”. Both rectifier types can be operated with the boost inductors located either on the DC or the AC side of the rectifier. The resultant rectifier circuit configurations have an excellent immunity to the “shoot-through” fault condition and use active switching elements with low per-unit current ratings and low switching losses. These features increase the reliability factor and lower the cost penalty associated with unity fundamental power factor three-phase rectifiers. Test results are presented for the rectifiers using simulation and experimental results     

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.     

An Efficient Power-Factor Correction Scheme for Plasma Display Panels

This paper presents an efficient power-factor correction (PFC) scheme for plasma display panels (PDPs) to reduce harmonic currents and power consumption. A high-efficiency interleaved boost converter is proposed, which can reduce the conduction losses and diode reverse-recovery problems in the continuous-conduction-mode operation. A zero-current switching (ZCS) condition is obtained to solve the reverse-recovery problems of the output diodes. In addition, a control strategy is suggested for the use of the proposed converter in a practical design. A high power factor can be achieved without sensing the input voltage. The analysis of the proposed converter and its design considerations are presented in detail. The experimental results based on a 600-W prototype are discussed to evaluate the proposed converter for a PFC circuit in a 50-in PDP power supply unit.