共查询到19条相似文献,搜索用时 640 毫秒
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本文对现有的应用直接功率转换(DPT)技术的单级PFC AC-DC变换器进行了深入的分析和综合.阐明了它们的直接功率转换的机理和实现方法。分析表明.应用DPT技术不仅可以有效地降低单级PFC AC-DC变换器的直流母线电压.也较大地提高了效率.使其在小功率的应用中具有更大的前景。 相似文献
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过高的直流母线电压应力(即中间储能电容电压应力)是困扰单级功率因数校正AC/DC变换器的一个严重问题。本文分析了单级功率校正AC/DC变换器产生高电容电压应力的原因,介绍了三种典型的根据直接功率传递原理改进的单级PFC变换器拓扑,对这几个拓扑的直流母线电压应力进行了深入的分析和比较。 相似文献
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由于Boost型功率因数校正(PFC)变换器输出电压必须高于交流电压峰值,因此当负载电压较低时,其需要级联直流/直流(DC/DC)变换器,不利于系统效率提高。以优化PFC变换器随电网电压变化的瞬时效率、进而提升整体效率为目标,研究了一种单相三端口PFC变换器。通过将传统三电平Boost变换器的低压侧分压电容直接用作负载输出端口,并构造出一个高压端口,可以实现交流输入侧和直流负载侧之间的准单级功率变换,有效减小了系统中功率变换的级数,从而实现PFC变换器整体效率的提升。此外,准单级功率变换的特性还有利于减小后级DC/DC变换器的电压电流应力和功率损耗,进一步提高交流/直流(AC/DC)变换器的整体效率。文中详细分析了三端口PFC变换器的工作原理和控制策略,建立了损耗分析模型并进行了仿真验证。最后,利用2kW实验样机验证了所研究变换器在改善系统效率方面的有效性。 相似文献
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基于反激变换器的无频闪LED驱动电源 总被引:1,自引:0,他引:1
为解决具有功率因数校正(PFC)功能的发光二极管(LED)AC/DC驱动电源存在的工频闪烁问题,提出了一种Flyback-Buck LED驱动电源。它由一个双输出绕组反激(Flyback)PFC变换器和一个Buck变换器构成,Flyback PFC变换器的辅助绕组作为Buck变换器的输入,Buck变换器的输出与Flyback PFC变换器的输出串联。通过Buck变换器有效补偿二次工频纹波,消除了LED频闪。Flyback-Buck大部分功率只经Flyback PFC单级变换,与两级变换拓扑相比,该拓扑具有较高的效率。最后,通过一台0.7 A/50W的实验样机,验证了理论分析的正确性。 相似文献
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使用无损吸收电路,能够提高硬开关PFC的工作频率,并降低开关损耗。应用全桥移相移开关技术,实现了DC/DC变换器的大功率输出。通过应用这两种技术,研制HF220/10型高频开关电源。 相似文献
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1 Introduction Dimmers are very widely applied in theatres,cinemas,auditoriums and signal systems.They are usually supplied by single-stage AC/AC converters in thepast with voltage regulation technique.Light dimmingrequests the power supply voltage fromth… 相似文献
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直流调制单级功率因数校正交-交变流器 总被引:1,自引:0,他引:1
功率因数校正是产生或吸收无功功率力图达到功率因数等于1.单级交-交变流器被广泛应用在各工业领域.传统的交-交变流器采用电压调制法,全谐畸变高,功率因数低,功率转换效率差.本文介绍全新直流调制方法,由直流变流技术实现.直流调制单级功率因数校正交-交变流器有效地改进了功率因数,使之达到0.999,功率转换效率达到97.8%.实验结果证实了设计和计算的正确性. 相似文献
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基于PFC技术的高效率双闭环DC/DC变换器 总被引:3,自引:3,他引:0
为提高DC/DC变换器系统的效率,运用功率因数校正(PFC)控制技术,在整个变换器系统中引入了电流和电压2种组态的负反馈,采取了降低损耗的措施,设计出一款用于电源和功率设备的12V/24V双闭环DC/DC变换系统,并进行了该系统稳定性、效率特性仿真实验和硬件电路实验。实验结果表明,所设计的DC/DC变换系统是稳定的,它的效率在稳定工作范围内达到85.0%~88.7%,其最高效率比目前国内外同类变换器高出约3%,其中12V、24V变换系统的输出纹波电压分别约为23mV和30mV,因而尤其适用于低功耗开关电源和中等功率设备。 相似文献
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Ahmed A. Hossam-Eldin Ahmed A. Elserougi Ahmed K. Abdelsalam Abdelrahman M. Farghly 《International Journal of Circuit Theory and Applications》2020,48(10):1583-1613
Renewable energy sources (RESs) need power-electronics-based converters to deliver the acquired power to the grid. Those converters should provide voltage-bucking/boosting capabilities to accommodate various grid modes specially for three-phase distorted commonly unbalanced distribution utility networks. Several power electronic-based converters have been elaborated to fulfill this high-demand market. Single-stage converters are the most dominant in the market where the current source inverters (CSIs), impedance source inverters (ZSIs), and boost inverters are the high-end candidates. The aspects of cost, footprint, and minimal numbers of active switches, in addition to simplified controllability, build the main challenges that face the evolution of robust renewable energy-associated grid-tied converters. This paper presents a novel three-phase differential-mode buck-boost inverter based on two bidirectional buck-boost DC/DC converters and one differential power processor (DPP) unit. The proposed topology is a single-stage DC/AC converter offering bucking/boosting capability, with reduced hardware requirements. The proposed topology features a simplified control methodology in addition to reduced size and cost of the hardware setup which makes it more suitable for grid-tied renewable energy applications. The operation principles, small-signal model, and control strategy of the proposed topology are also illustrated. Simulation and experimental results are presented in details to verify the topology-enhanced performance under various operating conditions. The deducted results elucidate the viability of the proposed configuration alongside with the claimed merits. 相似文献
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系统并深入地分析了单级和双级功率因数校正(Power Factor Correction,简称PFC)AC/DC变流器的性能特征,指出了它们各自存在的优缺点.在此基础上,结合软开关技术特点,提出了一种基于集成化设计的双级PFC AC/DC开关变流器电路.该电路克服了传统单级和双级变流器存在的不足,具有高效、高功率因数和低成本的特点.此外,还给出了该电路的实验结果. 相似文献
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目前,对单级功率因素校正电路的研究大多集中在小功率应用领域,为此该文提出一种能够应用于中大功率场合、实现了零电流开关的单级高功率因数AC/DC变换器拓扑。通过在全桥变换器中增加辅助开关实现了PWM控制,它不仅能够在很宽的负载范围内实现零电流开关和功率因数校正,而且解决了全桥谐振电路中。在不采用移相控制的情况下,必须采用PWM控制策略的问题。与2级式功率因数校正电路相比,提高了动态响应的速度、降低了成本,并且开关管的电压应力较低。仿真和实验分析验证了变换器的优越性。 相似文献
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Amir Bagheran 《电力部件与系统》2020,48(6-7):682-696
Abstract The high-brightness light-emitting diodes (LEDs) require an AC/DC converter with power factor correction (PFC). The large output electrolytic capacitor, which is used to minimize the low frequency LED current ripple, degrades the operating lifetime of the LED driver. In order to increase the lifetime of an AC–DC LED driver, the electrolytic capacitor should be eliminated without significantly increasing the output current ripple. In this article, an isolated single-stage single-switch AC/DC high power factor LED driver without electrolytic capacitor is proposed in which a zeta power factor (PF) corrector is integrated with a forward converter. The detailed theoretical analysis and design procedure of the proposed single-stage PFC converter is presented. The experimental results of a 110 Vrms, 21?W prototype verify the theoretical analysis. The input PF is 0.99 in the proposed converter that complies with lighting equipment standards such as IEC-1000-3-2 for class C equipment. 相似文献
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Mathematical modelling for power DC/DC converters is a historical problem accompanying DC/DC conversion technology since 1940‘s. The traditional mathematical modelling is not available for complex structure converters since the differential equation order increases very high. We have to search other way to establish mathematical modelling for power DC/DC converters. We have theoretically defined a new concept - Energy Factor (EF) in this paper and researched the relations between EF and the mathematical modelling for power DC/DC converters. EF is a new concept in power DC/DC conversion technology, which thoroughly differs from the traditional concepts such as power factor (PF), power transfer efficiency (η), total harmonic distortion (THD) and ripple factor (RF). EF and the subsequential EFV (and EFVD ) can illustrate the system stability, reference response and interference recovery. This investigation is very helpful for system design and DC/DC converters characteristics foreseeing. Two DC/DC converters: Buck converter and Super-Lift Luo-Converter.as the samples are analysed in this paper to demonstrate the applications of EF, EFV (and EFVD ), PE,SE, VE (and VED ), time constant τ and damping time constant τd. 相似文献