基于单周期控制的工作于DCVM的PFC CUK电路设计

文章针对工作于DCM的DC/DC变换器电流应力大、损耗大、效率低、输入电流纹波大等问题,采用工作于不连续电容电压模式(DCVM)的Cuk变换器作为APFC的主电路,并利用单周期控制技术实现闭环控制,不仅能够自动消除一个周期内的稳态和瞬态误差,而且可以有效地抑制输入扰动,动态响应快,克服了传统PWM电压反馈控制的缺陷。仿真结果证明了理论分析的正确性。     

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。     

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。     

基于BCM的有源功率因数校正电路的实现

分析整流电路的拓扑结构和工作模式,探讨该整流电路关键参数的选取依据,提出临界导电模式（BCM）功率因数校正Boost开关变换器的设计方法。仿真结果表明．所设计的以MC33262为核心的临界导电模式有源功率因数校正（APFC）电路能在90～270V的宽电压输入范围内输出稳定的400V直流电压,并使得功率因数达0．99,系统性能优越．达到设计要求。     

DC/DC变换电路的仿真研究

该文阐述了直流斩波电路(Buck电路和Cuk电路)的电路结构和工作原理,并利用Multisim进行了电路的仿真。首先运Multisim画出Buck电路和Cuk电路的仿真原理图,并设置了采集输出电压的电压表和电流表和示波器,然后分别分析电力MOSFET在导通和关闭时的电路工作状态,电流流经路径,以此推导Buck电路和Cuk电路的输入电压与输出电压关系,要实现降压,Buck电路的占空比α调节范围0～1之间,Cuk电路的占空比α调节范围0～50%。然后使用画出的原理图进行仿真电路的工作波形,使用24V的直流输入电压,得到12V的直流输出电压,Buck电路的占空比设置为50%,通过仿真结果分析得出Buck电路的输出电压是11,768V,Cuk电路占空比33.3%,输出电压为-12.2V,与分析的输出电压极性与输出电压极性相反,数值是正确的,且要求的误差小于5%。通过调节Buck电路和Cuk电路的占空比可以将输入直流电压斩波变换为输出电压不等的电压值。     

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。     

基于BCM的有源功率因数校正电路的实现

分析整流电路的拓扑结构和工作模式,探讨该整流因数校正Boost开关变换器的设计方法.仿真结果表明,所设计的以MC33262为核心的临界导电模式有源功率因数校正(APFC)电路能在90～270 V的宽电压输入范围内输出稳定的400 V直流电压,并使得功率因数达0.99,系统性能优越,达到设计要求.     

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。     

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.     

A Very Simple Control Strategy for Power Factor Correctors Driving High-Brightness LEDs

This paper presents a new control strategy for power factor correctors (PFCs) that are used to drive high-brightness LEDs. This control strategy is extremely simple and is based on the use of a conventional peak-current-mode controller with a suitable selection of the compensation ramp waveform. Neither an analog multiplier nor an input voltage sensor is needed to achieve quasi-sinusoidal line waveforms at nominal conditions and full load. If the converter belongs to the flyback family (flyback, buck–boost, SEPIC, Cuk and Zeta), the line waveform appears notably distorted if the compensation function is a linear ramp, but becomes almost sinusoidal if the linear ramp is substituted by a properly chosen exponential function. The line waveform is slightly distorted when the load varies or when the converter works under either overvoltage or undervoltage conditions. However, the waveform maintains a very high power factor (PF) even under these conditions. Moreover, the line current is cycle-by-cycle-controlled due to the peak-current-mode control, and hence, the input-current feedback loop is extremely fast, thereby allowing this type of control to be used with high-frequency lines (above 400 Hz).      

Analysis, design, and optimization of a secondary-side resonantconverter operating in the discontinuous capacitor voltage mode

A high-frequency link parallel resonant DC/DC power converter (PRC) operating in the lagging power factor mode with the resonating capacitor on the secondary side of the high-frequency (HF) transformer is analyzed for operation in the discontinuous capacitor voltage mode (DCVM) using a state-space approach. Converter equations are solved for operation under steady-state condition. Based on the analysis, design curves are obtained for DCVM operation. A method of obtaining the optimum operating point under certain constraints for DCVM operation is developed and is used to develop a simple design procedure. Experimental results obtained with a MOSFET-based 1 kW PRC are presented to support the theory     

High-precision current source using low-loss, single-switch,three-phase AC/DC converter

A three-phase AC/DC converter based on isolated Cuk topology feeding an inductive load is presented. The main goal is to get a compact, highly stable current source to feed an electromagnet. A high power factor is achieved, at constant duty-cycle and switching frequency, by discontinuous input current mode operation. The converter presents a linear relationship between the duty-cycle and the output current, making it easier to design the control system. Additionally the voltage stress on the power transistor is constant and does not depend on the duty-cycle. An auxiliary circuit allows zero voltage turn-off while limiting the over-voltage on the switch produced by the transformer leakage inductance. Pulse-width modulation (PWM) control is used to reduce sensitivity to line disturbances and to eliminate the 300-Hz ripple on the output current. Experimental measurements taken on a 400-W prototype confirm theoretical forecasts     

Power-factor correction using Cuk converters indiscontinuous-capacitor-voltage mode operation

The characteristics of Cuk power converters in discontinuous-capacitor-voltage mode operation are studied. A Cuk power converter in this mode of operation is an inherent power-factor corrector and features soft turn-off switching. Simulation and experimental results are reported to verify the theoretical analysis. In addition, the advantages and disadvantages of power factor correction circuits using Cuk power converters in discontinuous-inductor-current mode operation and Cuk power converters in discontinuous-capacitor-voltage mode operation are discussed     

Transformerless DC-to-DC converters with large conversion ratios

A novel switching DC-to-DC converter is introduced in which large voltage step-down ratios can be achieved without a very small duty ratio and without a transformer. The circuit is an extension of the Cuk converter to incorporate a multistage capacitor divider. A particularly suitable application would be a 50 V to 5 V converter in which DC isolation is not required. The absence of a transformer and a larger duty ratio permits operation at a high switching frequency and makes the circuit amenable to partial integration and hybrid construction techniques. An experimental 50 W three-stage voltage divider Cuk converter converts 50 V to 5 V at 500 kHz, with an efficiency higher than that for a basic Cuk converter operated at the same conditions. A corresponding voltage-multiplier Cuk converter is described, as well as dual buck-boost-derived step-down and step-up converters     

一种基于线性功放技术的DC/AC变换器

介绍了一种基于线性功放技术的DC/AC变换器.该DC/AC变换器主要由控制电路和线性功率放大电路构成.采用二阶有源滤波技术、稳幅技术及线性功放技术,实现输入500 Hz方波信号到输出500 Hz正弦波信号的转变.这种DC/AC变换器具有输出波形失真度小,输出幅度稳定性高等特点.     

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.     

基于NCP1654的高功率因数电源的设计

为了减少电力电子装置引起的谐波污染,加入APFC控制策略是一种有效的方法。有源功率因数校正电路使输入电流波形跟踪输入正弦交流电压波形,得到较高的功率因数。文章主要针对APFC控制方法进行讨论,介绍了NCP1654控制电路,并设计了600 W功率电路,实验结果证明了此校正电路的优良性能。     

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