一种可切换工作模式的反激开关电源

反激变换器存在电感电流连续模式（CCM）和断续模式（DCM）两种工作状态。通常选取处于CCM与DCM的临界状态作为工作点,设计反激开关电源的补偿回路。该折衷方案虽能兼顾两种工作模式,但存在带宽较小、动态响应差的问题,且在轻载情况下尤为突出。针对该问题设计了一种可切换工作模式的反激开关电源,对CCM和DCM模式分别设计环路补偿网络,通过变压器原边电流判断负载情况,进而切换补偿网络,实现电源工作模式的切换。设计了输出功率120 W的反激开关电源样机,进行仿真和样机性能测试,试验结果表明,电源不仅能根据负载情况切换工作模式,而且轻载时具有很好的动态响应,验证了该方案的有效性,与预期设计结果相符。     

Soft switching based on analysis of transient and steady-state characteristics: Application to a single-ended high-frequency inverter

A single-ended resonant-type high-frequency inverter using a static induction transistor (SIT) described in this paper can be performed as a zero current switching (ZCS) operation without dc reactor. The SIT high-frequency inverter is a low-cost one which has no transformer and it would be developed for a high-intensity ultrasonic power supply and dc-dc converter. The circuit operation regions, not only ZCS but also ZCS-ZVS (zero current switching and zero voltage switching), were elucidated in the normalized plane. The characteristics of the inverter including the power control by frequency regulation were discussed. Furthermore, the switching characteristics in the transient-state were investigated. These characteristics were substantiated on the basis of the numerical analysis and experimental results.     

一种新型的软开关正弦波PWM逆变器

为实现一种结构简单、高效、高频、低电压应力、易于控制的软开关三相逆变器控制.提出了一种新型的三相谐振极型软开关PWM逆变器,它与传统的辅助谐振极逆变器(ARCPI)不同,避免了ARCPI使用的2个大电容,没有中性点电位的变化问题.它的三相谐振电路之间是相互独立的,这就使得逆变器易于应用各种控制策略.本文选取一相电路,对其工作原理进行了分析,给出了不同工作模式下的等效电路图和最优电路设计.仿真和试验结果表明:逆变器的主开关和辅助开关都能实现软开关,谐振电路功率小,对减少电磁干扰和提高效率很有意义.     

Analysis,simulation and verification of a bipolar current source power resonant inverter

A high‐frequency bipolar current source resonant inverter introduced in this paper has dramatic zero‐voltage‐switching (ZVS) characteristic. The analytic expressions of the resonant voltage and current are given. It indicates that the resonant waveform is composed of two parts, i.e. the oscillatory component and the stationary component. In special cases, the resonant waveform degenerates into the mono‐frequency component, as presents the graceful sinusoidal wave with very low total harmonic distortion (THD) value. Based on the closed‐form voltage and current, the component stresses on reactive elements are obtained. The impact of different component values and operating frequencies on ZVS feature is also discussed. It should be noted that the ZVS merit may be lost if the components are carelessly selected. The validity of the theoretical analysis has been proven with Pspice simulations and experimental results. Copyright © 2004 John Wiley Sons, Ltd.     

光伏逆变器中反激式辅助开关电源的设计

在光伏逆变器系统中需要一个高效稳定的辅助电源,在对该电源的工作原理与设计方法进行分析的基础上,采用TOP 258智能开关电源芯片设计了一种多路隔离的反激式开关电源作为光伏逆变器的辅助电源,结果证明该电源有体积小、效率高的特点,可以满足光伏逆变器的要求。     

结构简单的谐振极型零电流软开关逆变器

针对谐振极型零电流软开关逆变器的拓扑电路的辅助开关较多所导致的逆变器体积大、成本高、效率低以及控制策略复杂等问题,提出一种结构简单的谐振极型零电流软开关逆变器拓扑电路,逆变器的每一相仅使用了1个辅助开关、1个谐振电感、1个谐振电容和2个辅助二极管来完成电路谐振。因此,该拓扑电路可以减小逆变器体积,降低成本,简化控制策略和提高效率。分析了逆变器在不同模式下的工作原理,给出了软开关实现条件和实际参数设计过程,建立了辅助电路功率损耗的数学模型。制作了一台2 k W的单相实验样机和一台6 k W的三相实验样机,实验结果表明该逆变器的主开关和辅助开关器件都可以实现零电流软开关。该软开关逆变器可以降低损耗和提高效率。     

零电流开关电流源谐振逆变器拓扑和参数计算

本文提出了一种电流源输出的LCC串并联谐振型逆变器（LCC－SPRI）主电路。逆变器能在负载阻抗较大幅度变化时保持输出电流基本恒定,槽路电流与负载电流相当,并能实现逆变开关零电流开通和关断。文章给出了槽路参数的设计方法及计算机仿真和实验室实验结果。     

反激PFC变换器输出电压纹波分析

详细分析了断续导电模式(DCM)反激功率因数校正(PFC)变换器和临界连续导电模式(CRM)反激PFC变换器实现功率因数校正的工作原理.通过推导DCM和CRM反激PFC变换器的输入电流的表达式,证明2种变换器都可以实现PFC功能.进一步推导DCM和CRM反激PFC变换器的输出电压纹波峰峰值的表达式,揭示了工作模式对PFC变换器的输出电压纹波的影响,发现CRM反激PFC变换器的输出电压纹波峰峰值比DCM反激PFC变换器的输出电压纹波峰峰值小.最后通过仿真和实验验证了理论推导的正确性.     

新型软开关切换反激式变换器的研究

针对现有的软开关切换反激式变换器辅助开关无法达到软切换及轻载时不能实现软切换的问题,提出了一种新型软开关切换反激式变换器,借助所加入的软开关辅助电路,和辅助开关上串联二极管,不仅能使主开关工作在零电压状态下切换,其辅助开关亦能在零电流状态下切换,也能避免辅助变压器的饱和。此外,所加入之辅助开关并非浮接而是和主开关共地,所以辅助开关的控制信号无需隔离,因而降低了控制电路的复杂度。实验结果表明:提出电路的主、辅开关在满载和轻载时都工作在软性切换状态,提高了电路在整个负载范围内的工作效率。     

电流模式DCM反激变换电路的建模和设计

对电流模式控制的反激变换电路进行了研究,建立了工作在电流断续模式下的反激电路小信号模型,给出了基于PWM控制芯片LD7670的单端反激电路的设计实例和电路分析。采用Math CAD对反激变换器控制环路的幅频特性和相频特性进行了分析,对控制环路进行了补偿网络设计,以提高系统的稳定性和瞬态响应。仿真和实验结果证明了模型的有效性,所设计的反激变换电路具有输入电压变化范围宽、动态响应快、电压调整率和负载调整率高的特点。     

一种抑制PWM逆变器电流纹波的变开关频率调制方法

提出了一种能够抑制PWM逆变器电流纹波的变开关频率调制方法.深入分析了PWM逆变器输出电流的特点,推导了电流纹波的解析表达式.通过使用该方法进行调制,可以使逆变器在不牺牲效率的前提下,有效降低电流纹波.与传统的恒定开关频率三次谐波注入法相比,所提出的变开关频率调制方法能够进一步提升电流纹波的抑制能力.最后,通过实验对所...     

Pulse current generator for driving tubular field emission lamp based on DCM flyback converter

This paper proposes a pulse current generator operated in discontinuous conduction mode for driving a tubular field emission lamp (TFEL). The proposed system based on flyback topology can provide pulse power driving to eliminate the temperature rise and arcing phenomenon caused by the traditional constant voltage driving. Therefore, both the lighting efficiency and lamp lifespan are improved. In this paper, an equivalent model of the TFEL is constructed to exhibit its capacitive characteristics. Moreover, the circuit configuration and each operation mode in a switching cycle are also described. And then a complete design considerations and mathematical model are discussed in detail. All the experimental results agree with the computer simulations to verify the theoretical predictions. Copyright © 2011 John Wiley & Sons, Ltd.     

一种软开关反激光伏并网逆变器的分析与设计

详细分析了一种反激光伏并网逆变器软开关电路的拓扑结构和工作过程。该软开关电路利用反激变压器的漏感与缓冲电容,在功率管开关过程中进行谐振,实现了漏感能量吸收再利用。在软开关电路中设计了调整电感,使谐振周期和谐振能量能够实现功率管漏源极电压箝位。在提高变换效率的同时降低了开关管关断电压尖峰。并据此设计了一台原理样机,实现了功率管的零电压开启,改善了逆变器的电磁兼容(EMI)特性,有效改善了并网电流波形质量。     

An active‐clamping zero‐voltage‐switching flyback converter with integrated transformer

This paper proposes an active‐clamping flyback converter using an integrated transformer. The proposed converter is composed of two active‐clamp flyback converters. The presented converter can balance the total load current between secondary sides of two transformers so that the rectifier diode conduction loss is reduced. Also, the main switch of one converter is the auxiliary switch for the other converter, so that only two switches are required and both can achieve zero‐voltage‐switching operation. The two transformers are integrated into one magnetic core; therefore, the volume and copper loss of transformer can be reduced. Detailed analysis and design of this integrated magnetic active‐clamping flyback converter are described. Experimental results are recorded for a prototype converter with an AC input voltage ranging from 85 to 135 V, an output voltage of 24 V and an output current of 5 A, operating at a switching frequency of 100 kHz. Copyright © 2014 John Wiley & Sons, Ltd.     

新型多功能反激式开关电源设计

以峰值电流型PWM控制芯片UC3842为核心设计了一种新型多功能反激式开关稳压电源,该电源具有6路直流隔离电压输出。介绍了其工作原理和外围电路设计。为了满足电磁兼容性和安全性要求,设计了EMI抑制电路。详细介绍了一种新型变压器绕组缓冲电路的设计方法,着重介绍了反激式变换器的变压器设计过程,包括齐纳箝位电压的计算、实际占空比的计算、电感值的计算、磁芯的选择、各路输出绕组匝数的确定以及气隙的计算。实现了对输出电压的负反馈调节及各种保护机制。实验结果表明,该开关稳压电源具有稳压性能优良,纹波小,电压调整率、负载调整率高,体积小,质量轻,电磁兼容性好等优点。     

Analysis and design of a dual‐mode control flyback converter

This letter presents a dual‐mode control scheme to improve the efficiency of a flyback converter in a wide load range. The proposed flyback converter features a novel dual‐mode operation. The valley‐switching technique is adopted to reduce the switching loss at light load. On the other hand, the fixed off‐time (FOT) controls with continuous conduction mode operations decrease the conduction losses at heavy load. The principles and design procedures of the proposed dual‐mode controller are discussed and analyzed. Finally, a 140‐W dual‐mode flyback converter with an output voltage of 19 V is implemented. Experimental results agree with the theoretical analysis. Copyright © 2012 John Wiley & Sons, Ltd.     

Analysis and implementation of a high‐efficiency zero‐voltage‐zero‐current‐switching DC–DC converter

A high‐efficiency zero‐voltage‐zero‐current‐switching DC–DC converter with ripple‐free input current is presented. In the presented converter, the ripple‐free boost cell provides ripple‐free input current and zero‐voltage switching of power switches. The resonant flyback cell provides zero‐voltage switching of power switches and zero‐current switching of the output diode. Also, it has a simple output stage. The proposed converter achieves high efficiency because of the reduction of the switching losses of the power switches and the output diode. Detailed analysis and design of the proposed converter are carried out. A prototype of the proposed converter is developed and its experimental results are presented for validation. Copyright © 2011 John Wiley & Sons, Ltd.     

A new topology for nonisolated multiport zero voltage switching dc‐dc converter

In this paper, a new multiport zero voltage switching dc‐dc converter is proposed. Multiport dc‐dc converters are widely applicable in hybrid energy generating systems to provide substantial power to sensitive loads. The proposed topology can operate in 3 operational modes of boost, buck, and buck‐boost. Moreover, it has zero voltage switching operation for all switches and has the ability to eliminate the input current ripple; also, at low voltage side, the input sources can be extended. In addition, it has the ability of interfacing 3 different voltages only by using 3 switches. In this paper, the proposed topology is analyzed theoretically for all operating modes; besides, the voltage and current equations of all components are calculated. Furthermore, the required soft switching and zero input currents ripple conditions are analyzed. Finally, to demonstrate the accurate performance of the proposed converter, the Power System Computer Aided Design(PSCAD)/Electro Magnetic Transient Design and Control(EMTDC) simulation and experimental results are extracted and presented.     

单相控制型软开关逆变器的最小复位电流控制

基于电感电流临界导通模式(critical conduction mode, CRM)的控制型软开关技术可实现开关管零电压开通(zero voltage switching, ZVS),但传统恒定电流复位方法的反向电流大,开关管通态损耗高。文中以单相三电平中点箝位型(three-level neutral point clamped, 3L-NPC)逆变器为研究对象,提出一种具有最小电感复位电流的控制方法。首先,分析开关管ZVS的实现条件,建立谐振等效电路分析模型,推导出电感复位电流理论最小值,在保证整个工频周期内开关管ZVS的同时,降低复位电流导致的开关管通态损耗。然后,建立逆变器损耗分析模型,将文中方法与传统恒定电流复位方法进行损耗计算与对比。最后,搭建一台1 kW的单相3L-NPC逆变器样机进行实验,结果表明文中方法相比于传统恒定电流复位方法,降低了损耗,最高变换效率提升约0.5个百分点。     

一种新型双极性电流源型谐振逆变器的研究

本文介绍了一种新型双极性电流源型谐振逆变器,该逆变器具有优异的零电压开关特性,能够显著地减小开关损耗。文章推导了谐振电压和电流的解析表达式,并且讨论了不同元件参数和开关频率对零电压开关特性的影响。PSpice仿真和实验结果验证了相应的理论分析。