基于推挽拓扑的输入并联输出串联直流变换器及其输出均压控制策略分析

在输出高电压场合,将较低的输入直流电压变换为较高的直流电压输出。输出端由于存在高压使得输出端器件承受较大的电压应力,存在变换器次级电压偏高、整流二极管电压应力大以及反向恢复时间长等问题。 基于此问题,提出以推挽变换器为基本单元,采用多个基本单元推挽变换器构成的输入串联输出并联变换器。为了确保该变换器系统的稳定可靠,从能量守恒的角度出发,分析了该变换器中各模块的输出均压之间的关系,给出了输出均压的实现条件。通过建立系统小信号模型,推导出系统的稳定条件,最后经试验验证了理论分析的正确性。     

一种小型化行波管高压电源的设计

介绍了一种小型化行波管高压电源.该高压电源采用电流馈电型主动箝位推挽隔离DC-DC变换器结构.详细分析了变换器的各工作模态,并给出了理论的工作波形,利用该变换器设计了一款小型化行波管高压电源.实测输出电压为7.5 kV,最大输出功率为200 W,拓扑效率最高可达94％.实验证明该高压电源具有体积小、重量轻、效率高、负载调整率好等特点,可适用于弹载、机载等低电压供电的特殊应用.     

基于推挽拓扑的输入并联输出串联变换器研究与设计

在输出高电压场合,由于存在高压存在,使得输出端器件承受较大的输出高电压和高电压应力。为解决输出端电压应力高等问题,提出以推挽变换器为基本单元,采用多个基本单元在输入端并联且在输出端并联,以此构成以推挽变换器为单元的输入串联输出并联组合式变换,给出了组合式变换器系统的小信号模型以及均压稳定条件,根据建立系统小信号模型以及实验样机参数要求,给出变换器驱动电路、变压器磁参数以及逐周期保护电路设计方式。最后经试验验证了理论分析 的正确性。     

一种多输出电流馈电推挽变换器的电流反馈控制方法

 本文提出了一种应用于多输出BUCK电流馈电推挽变换器的电流反馈控制方法.该控制方法等效于可变权系数的加权电压控制方法,其通过将反馈变量采样点由输出支路转移至变压器原边输入端并利用电感电流加以补偿从而实现对各支路输出电压的均衡调节.这一控制方法在简化反馈环节的同时改善了各支路输出电压的负载调整特性.分析过程考虑了主要的传导损失.仿真与实验结果证明了该控制方法的有效性.     

大功率全桥变换器的趼究与设计

开关功率变换器是现代电路理论的重要研究对象。开关电源的高频变换电路形式很多,常用的变换电路有升压、降压、推挽、全桥、半桥、单端正激和单端反激等形式,以上这些拓扑都是电压馈电拓扑,所谓电压馈电是指内阻很小的电压源向拓扑供电,在开关管不正常的情况下,该类输入电源是无法限制开关电流的。另外一种就是电流馈电拓扑,在该拓扑中,具有很高的瞬间阻抗的电感被加在输入电源和拓扑之间。     

矩阵变换器交流励磁控制系统的设计与实现

矩阵变换器是一种交交变频器,可以实现能量双向流动,适用于双馈电机交流励磁系统。文中主要研究了双馈型风力发电机矩阵变换器交流励磁控制系统的设计与实现,该控制策略是以定子电压和频率作为给定值,定子实际电压和转速作为负反馈,通过控制交流励磁,实现双馈电机定子电压和频率稳定输出。实验结果表明,在转速亚同步和超同步时,双馈电机定...     

基于锂电池化成的新型双向DC／DC拓扑结构研究与建模

提出一种用于锂电池化成技术的新型双向DC／DC拓扑结构。采用两级双向DC／DC拓扑结构,一级使用半桥双向变换器,另一级使用Buck—boost双向变换器,用数字信号处理器对Buck—boost双向变换器进行闭环控制,能实现输入电压和输出电压有较大压差的情况下进行变换。在Matlab／Simlink下对该拓扑结构进行验证。结果表明,该变换器性能稳定,能有效地实现3V电池电压和400V母线电压双向变换。     

驱动式DC-DC变换器设计

为了对直流电压进行变换,采用DC-DC技术,设计输出电压可调的直流电压变换器。变换器包括驱动式方波电路、功率管组成的调整电路、比较采样电路和滤波电路。在multisim软件环境下进行仿真,并在实际电路进行测试,获得的结果满足设计要求。实验证明,升压变换器可实现输入5 V直流电压,输出12 V直流电压;降压变换器可实现输入12 V直流电压,输出5 V直流电压;具有良好的直流变换功能。     

5—12V推挽式开关电容DC—DC变换器的性能分析

对５－１２Ｖ推挽式开关电容ＤＣ－ＤＣ变换器的性能进行了理论分析及计算机仿真,结果表明,该结构的输出电流可达１Ａ以上,效率优于７５％,输出电压纹波小于２０ｍＶ,具有高功率密度、便于集成等优点。     

具有低纹波输出高增益DC-DC变换器

提出一种无耦合电感的交错式高升压比变换器拓扑。该结构由两个Boost电路和两个电压倍增单元组成,并以交错方式运行。所提变换器具备低电流纹波、低开关电压应力和高电压增益的特性。详细分析了变换器工作模态和电压增益特性,并与现有工作进行了对比分析。结果表明,输入电压为30 V时,输出电压高达300 V,并且开关管的电压应力仅为87 V,远低于传统变换器300 V的输出电压。最后,搭建了100 W的实验样机,实验结果验证了所提变换器的有效性。     

A high-performance, integrated magnetics scheme for buck-cascaded push-pull converter

This letter proposes a new integrated magnetics scheme for the buck cascaded current-fed push-pull converter. While integrating the transformer and inductor into a common structure, the proposed scheme also alters the operating characteristics of the basic converter. This leads to several advantages such as, continuous output current, zero voltage switching (ZVS), and zero current switching (ZCS) for the switches of the push-pull stage, and reduced conduction losses. The principle of operation of the proposed scheme is analyzed using the gyrator-capacitor model. Experimental results from a 12 V/5 A proof-of-concept prototype are presented demonstrating the advantages of the proposed scheme.     

DC-Voltage-Ratio Control Strategy for Multilevel Cascaded Converters Fed With a Single DC Source

Recently, a multilevel cascaded converter fed with a single dc source has been presented. An analysis of the steady-state working limits of this type of converter is presented in this paper. Limits of the maximum output voltage and the minimum and maximum loading conditions for stable operation of the converter are addressed. In this paper, a way to achieve any dc voltage ratio (inside the stable operation area of the converter) between the H-bridges of the single-dc-source cascaded H-bridge converter is presented. The proposed dc-voltage-ratio control is based on a time-domain modulation strategy that avoids the use of inappropriate states to achieve the dc-voltage-ratio control. The proposed technique is a feedforward-modulation technique which takes into account the actual dc voltage of each H-bridge of the converter, leading to output waveforms with low distortion. In this way, the dc voltage of the floating H-bridge can be controlled while the output voltage has low distortion independently of the desired dc voltage ratio. Experimental results from a two-cell cascaded converter are presented in order to validate the proposed dc-voltage-ratio control strategy and the introduced concepts.      

Novel Current-Mode AC/AC Converters With High-Frequency AC Link

A novel circuit-topology family of the current-mode AC/AC converter with high-frequency AC link, based on a Flyback converter, is proposed. These circuit topologies, which can transfer one unregulated sinusoidal voltage with high total harmonic distortion (THD) into another regulated constant-frequency sinusoidal voltage with low THD, are composed of input cycloconverter, high-frequency storage transformer, and output cycloconverter. The circuit-topology family includes single four-quadrant power switch mode, push-pull mode, half-bridge mode, and full-bridge mode circuits. The single four-quadrant power switch mode and push-pull mode converters are suitable for low input voltage fields, but the half-bridge mode and full-bridge mode converters are suitable for high input voltage fields. The operational mode, steady principle, and transient voltage feedback control strategy of the kind of converter are investigated. The output characteristic curve, its relation to internal resistance, and the design criteria for the key circuit parameters are given. The theoretical analysis and the test result of the 500 VA 220 V 15% 50 HzAC/220 V 50 HzAC prototype have shown that the converters have advantages such as high-frequency galvanic isolation, simple topology, two-stage power conversion [low frequency alternating current (LFAC)/high frequency alternating current (HFAC)/LFAC], bidirectional power flow, high efficiency, high power density, low THD of the output voltage, strong adaptability to various loads, higher line power factor, low audio noise, etc.     

串联H桥多电平高压变频器故障处理新方法

串联H桥的多电平高压变频提升机传动系统高速运行时,要求在变频器故障状态下能够继续运行,串联H桥型变频器功率单元出现故障时通常采用旁路、带电热插拔等硬件处理技术,但这些方法存在变频器的输出电压不对称、对操作人员人身安全有一定的危险等缺陷。本文对故障时开关状态进行调整实现从控制策略上进行故障处理,保障传动系统输出三相线电压对称,并且确保传动系统输出的零序电压最小,与旁路技术相比,在同样的故障状态下,能够输出更大幅值的合成电压矢量,为提升机提供更大力矩。仿真表明系统有较好的故障运行能力。     

基于IGBT的链式SVG的研究

具有独立电源的链式H桥多电平变流器具有每个H桥单元结构相同、所用元件数少、易于实现电路的模块化设计和封装等一系列优点,成为无功补偿的发展趋势。首先介绍了静止无功发生器（SVG）的基本工作原理,然后分析了链式H桥的特点,并根据主电路的结构设计了一种混合脉宽调制策略。最后,在saber仿真环境下建立SVG模型,并进行仿真。...     

高效率低纹波DC／DC变换器模块

介绍一种高效率、低纹波、高可靠的ＤＣ／ＤＣ变换器模块，其控制方式为传统的ＰＷＭ推挽形式．主要技术指标为：输入电压２０～４０Ｖ、输出电压±１２Ｖ、输出功率２０Ｗ、效率高达８８％、纹波小于１０ｍＶ、功率密度达到０．９３ｗ／ｃｍ３，特别适用于雷达、导弹、通讯、工业控制设备等要求高可靠、高效率、小体积、低纹波干扰的场合。     

Design of 48 V Voltage regulator modules with a novel integrated magnetics

The push-pull forward topology with the current-doubler and synchronous rectifier is a suitable approach for high-input voltage regulator modules (VRMs) used to supply high-performance microprocessors. In order to improve efficiency and reduce size, this paper proposes an improved push-pull forward converter with a novel integrated magnetics. All the magnetic components including input filter inductor, step-down transformer and output filter inductors are integrated into a single EI or EE core. This topology is essentially the modified push-pull converter with the built-in input filter and the coupled-inductor current doubler rectifier. The proposed integrated magnetic structure features a simple core structure, a small leakage inductance and low winding and core losses. A design is given for a 48-V VRM with a 1.2-V and 70-A output, and its experimental results show that the proposed approach can offer a great improvement in efficiency.     

Synthesis of Multilevel Converters Based on Single- and/or Three-Phase Converter Building Blocks

This paper synthesized a family of multilevel converters that is constructed by using multiple well-developed single- and/or three-phase converter building blocks. The resulting advantages include a modular structure that leads to convenient construction and maintenance as well as easy extension to higher voltage levels. One successful example from this family is the cascaded H-bridge converter, which is now widely used for volt-amperes reactive (VAR) compensation and motor drive applications due to its many advantages. Another emerging member is the Hexagram converter, composed of six interconnected three-phase converter modules, which has many eminent features such as lowered component count and lowered dc energy storage requirement compared to the cascaded H-bridge converter, and thus, is a promising candidate for high-power applications.