双绕组反激式单级PFC变换器及功率因数改善措施研究

为改善功率变换器的功率因数,提出一种双绕组反激式单级功率因数校正PFC(Power Factor Correction)变换拓扑。该拓扑由Boost PFC电路和具有串并联结构的双绕组反激变换电路组合而成,利用2个中间储能电容吸收变压器初级绕组的漏感能量,有效地抑制功率器件的电压应力,提高变换器的可靠性。详细分析了变换器的工作原理和稳态特性,并在传统的单电压环控制方法的基础上,将整流电压引入到控制电路,提出了一种简单的电压补偿控制方法来提高变换器的功率因数、降低输入电流的总谐波畸变率。设计制作了一台150 W/24 V实验样机,实验结果验证了所提出电路原理的正确性和采用电压补偿控制方法改善输入电流波形质量的有效性。     

并联型双耦合绕组反激式单级PFC变换器

在双耦合绕组反激式单级PFC变换拓扑的基础上,引入并联功率传递单元,提出一种并联型双耦合绕组反激式单级PFC变换拓扑.该拓扑通过在Boost电感上增加二次绕组,使部分能量直接由Boost电感传给负载,从而提高了变换器的效率,并且能够限制中间储能电容电压和减小开关器件的电压电流应力.本文详细分析了该变换拓扑的工作原理和稳态特性,讨论了变换器的参数设计.150W/24V样机实验结果表明该拓扑具有高效率、高功率因数、低开关电压应力等特点.     

具有电压负反馈绕组的新型反激式单级功率因数校正变换器

提出一种具有电压负反馈绕组的新型反激式单级PFC变换拓扑。电压负反馈绕组的引入能够抑制中间储能电容电压,减小开关管的电压电流应力,解决了DCM PFC+ CCM DC/DC模式下轻载时,中间电容电压过高的问题,并且一部分输入功率将通过负反馈绕组直接传向负载,提高了变换器的效率。通过对电路工作模态和稳态的分析,可以得出该变换拓扑不仅具有较好的功率因数校正能力,还具有开关管电压应力低、效率高等优点。实验结果证明了该变换拓扑的优越性。     

基于Flyboost模块的新型单级功率因数校正变换器

提出了一种新型的功率因数校正模块(flyboost模块)，它具有两种工作状态(反激变换器状态和Boost电感状态)。基于这种PFC模块，得到了一种新型的单级PFC变换器，实验汪明这种变换器不仅可以得到很高的功率因数，而又可以显提高变换器的效率并自动限制中间储能电容上的电压。     

一种高效率次级谐振单级反激PFC变换器

针对传统单级反激功率因数校正PFC(power factor correction)变换器存在工作效率低、变换器开关管和输出二极管电压应力大等缺点,研究了一种次级谐振单级反激PFC变换器,不仅能够合理利用次级漏感能量,提高变换器效率,而且有效解决了传统单级反激变换器开关管、输出二极管电压应力较大的问题;同时还分析了次级谐振单级反激PFC变换器工作于电感电流断续模式DCM(discontinuous current mode)时的工作模态及其稳态工作特性,并将该变换器应用于LED驱动电路。最后,通过实验验证了理论分析的正确性。     

一种交错并联反激式三电平DC-DC变换器

本文在传统反激变换器基础上,引入三电平技术,并针对传统反激三电平DC-DC变换器电源两端并联的分压电容不均压的问题,提出了一种交错并联反激式三电平DC-DC变换器。该变换器具有电路拓扑简洁,输出只需电容滤波,减小输出滤波器,提高了变换器功率密度等优点。深入分析了该变换器的工作原理及工作过程,推导了其输入输出关系,和传统的反激两电平变换器相比,可以得出该并联交错三电平反激变换器能减小输出电容,降低功率开关管电压应力等结论。最后设计了闭环控制策略,并基于saber对电路进行仿真,验证了该拓扑的正确性和输出电容小、功率开关管电压应力低等特点。     

低输出电压纹波准单级反激PFC变换器

提出了一种低输出电压纹波准单级反激功率因数校正(PFC)变换器,它由1个双输出反激变换器和1个具有快速动态响应能力的Buck变换器组成,Buck变换器由双输出反激变换器的辅助输出供电,其输出与双输出反激变换器的主输出串联给负载供电。双输出反激变换器用于实现PFC功能;Buck变换器补偿双输出反激变换器主输出的2倍工频电压纹波,实现低输出电压纹波和快速动态响应。实验结果表明,在保持同样功率因数值的前提下,准单级反激PFC变换器极大地减小了单级反激PFC变换器的输出电压2倍工频纹波,其动态响应速度远快于单级反激PFC变换器,与两级级联PFC变换器的动态响应速度相近,并获得了高于两级级联PFC变换器的效率。     

基于DSP控制的有源箝位正反激变换器研究

提出一种基于数字信号处理(DSP)控制的有源箝位正反激变换器。该拓扑由反激变换器次级配合不对称半桥倍压整流电路构成。其变压器除了能作为反激耦合电感传递能量外,还能在主开关管开通时向次级倍压电容传递能量,提高了变压器的利用率。而且通过DSP控制,变换器的输入电压和负载改变时,均能保持稳定的电压输出。此外,初级开关管均能实现全负载范围软开关,提高了变换器效率。详细分析了变换器的工作原理及DSP控制策略的实现方式,搭建了一台300 W实验样机并证明了理论分析的正确性。     

一种新颖的ZVT Boost变换器

脉宽调制（Pulse Width Modulation,简称PWM）Boost变换器被广泛用作DC/DC变换器和功率因数校正装置。提出了一种新颖的零电压转换（Zero Voltage Transition,简称ZVT）Boost变换器,利用能量反馈辅助电路实现了升压管的ZVT和升压二极管的软开关。辅助电路由辅助开关管、耦合电感（反激变压器）和反馈二极管构成。辅助开关管实现了零电流开通和近似零电压关断,变换器的效率较高,电磁干扰低。在辅助开关管关断时,耦合电感将谐振电路中的能量馈送至电源端,功率器件的电压电流应力较低,辅助电路的传导损耗较小。详细分析了该变换器的工作原理,并通过样机进行了验证。     

储能电感对二次型Boost PFC变换器的性能影响

相比于断续导电模式(DCM)Boost功率因数校正(PFC)变换器,输入电感L1和储能电感L_2均工作于DCM的二次型Boost PFC变换器的输出电压纹波明显减小,但其功率因数(PF)较低。首先分析了电感L1工作于DCM的二次型Boost PFC变换器PF值表达式,指出可通过适当增大变换器中间电容电压VC1以提高PF值。其次,研究了电感L_2取值对中间电容电压及其电压纹波的影响。研究结果表明,当L_2工作于DCM时,可以通过设置较大的电感L_2/L1比值,以实现变换器更高的功率因数和更低的输出电压纹波。仿真与实验结果验证了理论分析的正确性。     

Pulse current regenerative resonant snubber‐assisted two‐switch flyback‐type ZVS PWM DC‐DC converter

In this paper, a two‐switch high‐frequency flyback transformer‐type zero voltage soft‐switching PWM DC‐DC converter using IGBTs is proposed. Effective applications for this power converter can be found in auxiliary power supplies of rolling stock transportation and electric vehicles. This power converter is basically composed of two active power switches and a flyback high‐frequency transformer. In addition to these, two passive lossless snubbers with power regeneration loops for energy recovery, consisting of a three‐winding auxiliary high‐frequency transformer, auxiliary capacitors and diodes are introduced to achieve zero voltage soft switching from light to full load conditions. Furthermore, this power converter has some advantages such as low cost circuit configuration, simple control scheme, and high efficiency. Its operating principle is described and to determine circuit parameters, some practical design considerations are discussed. The effectiveness of the proposed power converter is evaluated and compared with the hard switching PWM DC‐DC converter from an experimental point of view, and the comparative electromagnetic conduction and radiation noise characteristics of both DC‐DC power converter circuits are also depicted. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(3): 74–81, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20081     

反激式隔离型高增益DC/DC变换器

提出了一种反激式隔离型高增益DC/DC变换器.该变换器利用反激变压器的变比和开关电容来提高输出电压增益,满足输入输出的电气隔离.开关电容的引入,使得反激变压器副边绕组在开关管闭合时给倍压电容充电,在开关管断开时给负载供电,提高了变压器绕组的利用率,还解决了反激变换器输出二极管与漏感的谐振问题.由于变压器漏感的原因使得所...     

Quasi‐active power factor correction on flyback‐based dc/dc converter

This paper presents a novel input current shaper based on a quasi‐active power factor correction (PFC) scheme. In this method, high power factor and low harmonic content are achieved by providing an auxiliary PFC circuit with a driving voltage which is derived from a third winding of the transformer of a cascaded dc/dc flyback converter. It eliminates the use of active switch and control circuit for PFC. The auxiliary winding provides a controlled voltage‐boost function for bulk capacitor without inducing a dead angle in the line current. Since the dc/dc converter operates at high switching frequency, the driving voltage is also of high switching frequency, which results in reducing the size of the magnetic components. Operating principles, analysis and experimental results of the proposed method are presented. Copyright © 2011 John Wiley & Sons, Ltd.     

An approach to achieve ride-through of an adjustable-speed drivewith flyback converter modules powered by super capacitors

Adjustable-speed drives under short-term power interruptions can interrupt a critical process. In this paper, an approach to provide ride-through with flyback converter modules powered by super capacitors is explored. The proposed approach is modular and facilitates additional modules to be added to suit higher voltage/power ratings. Both unidirectional and bidirectional flyback DC/DC converter topologies are examined. Simulation and experimental results are presented     

Two‐switch flyback PWM DC‐DC converter in continuous‐conduction mode

The two‐switch flyback DC‐DC converter is an extended version of the conventional single‐switch flyback converter. An additional switch and two clamping diodes serve as a simple, but an effective way to limit the switch overvoltages, which occur in the conventional single‐switch flyback converter due to the ringing of the resonant circuit formed by the transformer leakage inductance and the transistor output capacitance. The clamping diodes in the two‐switch flyback topology clamp the maximum voltage across each switch equal to the DC input voltage. This paper presents a detailed steady‐state analysis and design procedure of the diode‐clamped two‐switch flyback converter operated in continuous‐conduction mode (CCM). The power loss in each component of the two‐switch flyback converter is compared with those of the single‐switch flyback converters with and without RCD clamp, and is presented in a tabular form. The two‐switch flyback converter was bread‐boarded to validate the theoretical analysis. Experimental results from a 10 V/30 W, 100 kHz laboratory prototype verified that the maximum switch voltage is limited to the DC input voltage. Copyright © 2010 John Wiley & Sons, Ltd.     

Two‐switch flyback PWM DC–DC converter in discontinuous‐conduction mode

The two‐switch flyback DC–DC converter is an extended version of the conventional single‐switch flyback converter. An additional switch and two clamping diodes serve as a simple, but an effective way to limit the switch overvoltages, which occur in the conventional single‐switch flyback converter due to the ringing of the resonant circuit formed by the transformer leakage inductance and the transistor output capacitance. The clamping diodes in the two‐switch flyback topology clamp the maximum voltage across each switch equal to the DC input voltage. This paper presents a detailed analysis and design procedure of the diode‐clamped two‐switch flyback converter operated in discontinuous‐conduction mode (DCM). A comparison of power losses of the two‐switch and the single‐switch flyback converters is given. The two‐switch flyback converter was bread‐boarded to validate the theoretical analysis. Experimental results from a 20‐V/30‐W, 100‐kHz laboratory prototype verified that the maximum switch voltage is limited to the DC input voltage. Copyright © 2010 John Wiley & Sons, Ltd.     

一种高增益交错耦合电感DC/DC变换器

提出了一种高增益交错耦合电感DC-DC变换器,采用二极管、电容和电感构建无源吸收网络,回收再利用漏感能量,开关管的开关电压尖峰得到抑制,进而减小了开关管的电压应力;选用导通阻抗低的MOSFET,降低开关损耗,改善变换器效率。将2个电容和2个耦合电感副边相结合,1个导通周期内,当电容并联导通时,储存在耦合电感中的能量给电容充电;当电容串联导通时,将能量释放给输出端,从而获得高增益。此外,二极管的反向恢复问题得到有效抑制;交错并联控制抑制了输入电流纹波,变换器性能得到改善。对电路的操作原理和模态变化作了详细分析,最后搭建了1台300 W、20 V/240 V的实验样机,验证了理论分析的正确性。