丘克(Cuk)变换器的纹波电流及输出电压研究

建立了一种Cuk型DC／DC变换器的数学模型，并利用PSpiee软件对这种变换器进行仿真研究，分析其暂态和稳态的过程及纹波的形成机理。大量仿真研究表明，当电路元件取不同的参数时，输出电压就会按照一定的规律变化。仿真结果为实际电路的设计提供有益的参考。     

开关电源Boost变换器输出纹波的仿真研究

文章在分析典型DC-DC变换拓扑结构的基础上,建立了降压型（Boost）DC-DC变换器的PSpice仿真模型。在三种工作模式下,针对输入电压、电感和负载电阻对输出电压纹波都有不同程度的影响,对Boost变换器输出纹波电压的影响因素进行了分析。其结论为Boost型DC-DC变换器的设计和研制提供了理论依据。     

A Cascade Multilevel Converter Topology With Reduced Number of Switches

This paper introduces a new multilevel converter topology that has many steps with fewer power electronic switches. The proposed circuit consists of series-connected submultilevel converters blocks. The optimal structures of this topology are investigated for various objectives, such as minimum number of switches and capacitors, and minimum standing voltage on switches for producing maximum output voltage steps. A new algorithm for determination of dc voltage sources’ magnitudes has also been presented. The proposed topology results in reduction of the number of switches, losses, installation area, and converter cost. The operation and performance of the proposed multilevel converter has been verified by the simulation and experimental results of a single-phase 53-level multilevel converter.      

高频降压变换器的输出纹波分析

引言 同步降压型开关电源具有输出电流大、效率高等优点,非常适合电池供电、注重效率的便携式电子产品,如:笔记本电脑、个人数字助理(PDA)、数码相机(DSC)、手机等.为了适应市场需求,零部件模块的体积愈来愈小,为达到这一要求,电源变换器可通过提高开关频率减小对电感和电容的需求,达到缩小体积的目标.     

带中性点电压调节的级联型高压变频器拓扑研究

目前传统级联型高压变频器广泛应用于交流电机的调速,但是结构上的缺陷使得它无法将电机制动能量回馈至电网。本文提出了一种具有能量回馈功能的级联型高压变频器新型拓扑。在传统级联高压变频器拓扑的基础上,将浮空的中性点断开,串入一个双PWM变换器．并对串入的双PWM变换器建模,最后通过仿真验证,说明这种新型拓扑在电机制动时进行能量回馈的可行性。     

Modeling and Control of PV Charger System With SEPIC Converter

The photovoltaic (PV) stand-alone system requires a battery charger for energy storage. This paper presents the modeling and controller design of the PV charger system implemented with the single-ended primary inductance converter (SEPIC). The designed SEPIC employs the peak-current-mode control with the current command generated from the input PV voltage regulating loop, where the voltage command is determined by both the PV module maximum power point tracking (MPPT) control loop and the battery charging loop. The control objective is to balance the power flow from the PV module to the battery and the load such that the PV power is utilized effectively and the battery is charged with three charging stages. This paper gives a detailed modeling of the SEPIC with the PV module input and peak-current-mode control first. Accordingly, the PV voltage controller, as well as the adaptive MPPT controller, is designed. An 80-W prototype system is built. The effectiveness of the proposed methods is proved with some simulation and experimental results.     

Buck-Boost变换器的能量传输模式及输出纹波电压分析

根据电感电流最小值与输出电流的比较,将Buck-Boost 变换器的能量传输模式(ETM)分为完全电感供能模式(CISM)和不完全电感供能模式(IISM),得出了CISM和IISM的临界条件和临界电感.将电感电流最小值与零和输出电流进行比较,得出Buck-Boost 变换器存在三种工作模式,即CISM、不完全电感供能且连续导电模式(IISM-CCM)和不完全电感供能且不连续导电模式(IISM-DCM).推导出了变换器工作于三种模式时的输出纹波电压表示式,指出对于给定负载、电容和开关频率的Buck-Boost变换器,CISM的输出纹波电压最小且与电感无关,而IISM-CCM和IISM-DCM的输出纹波电压较大且随电感减小而增大.CISM和IISM的临界电感即为使得变换器的输出纹波电压最低的最小电感.文中给出实例,实验结果与理论分析一致,但因未考虑器件参数输出纹波电压略高于理论分析值,实验结果验证了理论分析的正确性.     

Improved Z-Source Inverter With Reduced Z-Source Capacitor Voltage Stress and Soft-Start Capability

This paper proposes an improved Z-source inverter topology. Compared to the traditional Z-source inverter, it can reduce the Z-source capacitor voltage stress significantly to perform the same voltage boost, and has inherent limitation to inrush current at startup. The control strategy of the proposed Z-source inverter is exactly the same as the traditional one, so all the existing control strategy can be used directly. A soft-start strategy is also proposed to suppress the inrush surge and the resonance of Z-source capacitors and inductors. The operation principle of the proposed topology and comparison with the traditional topology are analyzed in detail. Simulation and experimental results are given to demonstrate the new features of the improved topology.      

基于DCM模式的高压输出反激变换器

设计了一种工作在不连续导电模式(DCM)下的高压输出反激变换器.详细分析了工作在连续导电模式(CCM)和DCM的反激变换器稳态输出/输入传递函数,比较了这两种模式在不同负载条件下的电压输出能力.在理论分析的基础上得出:在一定的负载条件下,工作在DCM状态的反激变换器比工作在CCM状态下的反激变换器更适合高压输出电路.在试验电路上对这一结论进行了验证.     

一种输出电压可变的键控DC-DC转换电路

介绍一种ＤＣ－ＤＣ门控两电压输出转换电路。该电路具有电路结构简单、设计构思新颖的特点。无需调试即可达到高稳定的两组ＤＣ电压输出，且功率变换效率较高。另外，该电路的过载保护设计简单、可靠、灵敏，且具备自恢复性，特别适于开发各种应性产品。     

Modeling the Effect of Voltage Ripple on the Power Output of Photovoltaic Modules

This paper proposes a model for the static power loss in photovoltaic (PV) panels due to switching-frequency ripple. Small-signal modeling is used to determine the amplitude of the voltage ripple that is imposed on the PV panel, and a closed-form expression is developed for the output power. The expression is shown to be more accurate than the power loss that was predicted by small-signal modeling alone, resulting in a median error of 0.8%. The model presented allows dc-dc converter designers to more precisely choose the input filter components that are critical during times of low insolation.     

晶闸管变流装置控制电压与输出电压关系分析

晶闸管变流装置通过改变触发控制角α从而改变装置的输出电压,而α角与触发器电路的控制电压之间有着密切关系。正确分析与揭示控制电压与输出电压的关系,能为变流装置实现过流保护和闭环自动控制提供一个平台。     

A Nonisolated Single-Phase UPS Topology With 110-V/220-V Input–Output Voltage Ratings

A circuit configuration of a single-phase nonisolated online uninterruptible power supply (UPS) with 110-V/220-V input–output voltage ratings is proposed, allowing the bypass operation without a transformer even if the input voltage is different from the output voltage. The converter consists of an ac–dc/dc–dc three-level boost converter combined with a double half-bridge inverter. In this type of configuration size, cost and efficiency are improved due to the reduced number of switches and batteries, and also, no low-frequency isolation transformer is required to realize bypass operation because of the common neutral connection. Both stages of the proposed circuit operate at high frequency by using a passive nondissipative snubber circuit in the boost converter and insulated-gate bipolar-transistor switches in the double half-bridge inverter, with low conduction losses, low tail current, and low switching losses. Principle of operation and experimental results for a 2.6-kVA prototype are presented to demonstrate the UPS performance.      

A Novel Depletion-IMOS (DIMOS) Device With Improved Reliability and Reduced Operating Voltage

We experimentally demonstrate a novel depletion-IMOS (DIMOS) device with a 12.1-mV/dec subthreshold slope and 5-decade ON/OFF ratio, employing a depletion mode of operation instead of inversion. DIMOS structure improves reliability by reducing hot carrier injection and features 40% lower breakdown voltages with higher ON currents compared to conventional IMOS.      

一种改进的异步计数器分析方法

本文介绍一种改进的异步计数器分析方法，提出时钟约束状态方程的概念与计算方法；给出了分析步骤与典型实例。     

一种可实现宽范围电压输出的DC-DC变换器设计

提出了一种实用的可实现宽范围电压输出的平方型变换器,分析了该变换器工作原理,对主电路中的功率管、变压器、二极管、输出电容和输出电感等参数进行了设计。根据设计的结果,制作了变换器,并利用示波器采集了该变换器样机重要元器件的工作波形;对样机效率进行考察,全负荷工作效率在80%以上,占空比最大为0.65,验证了设计的正确性。     

隔离式低压大电流输出DC/DC变换器拓扑分析

从拓扑、应用方面论述了低压大电流变换器技术近期的发展。对隔离式DC/DC变换器原边和副边拓扑进行了分析和比较,得出了隔离式低压大电流输出DC/DC变换器的优选拓扑结构。阐述了带倍流整流的桥式拓扑、推挽正激拓扑以及改进型推挽正激拓扑的优点和工作特点。同时,介绍了能提高变换器效率的同步整流技术。     

双输出电压转换器实现简单、易用、低成本解决方案

无论何种应用,工程师都会面对要用负电压对特定功能的电路进行偏置的问题,这种需要常见于单电源供电系统中要高性能地析取或强加一个模拟信号。当然,用交流电源供电的任何系统都可以用交流／直流转换器的附加绕组来解决这一问题。但是,当采用单个电池供电时,情况就较为复杂。在这种情况下,采用简单的直流／直流转换器即可满足这种需要,而无须增大PCB占位面积或增加成本。     

一种低噪高输出电压DC—DC变换器设计

针对某航天器设备用的130V高压DC—DC变换器的低噪声要求,采用初级侧隔离的负载端直接反馈控制方式,次级侧采用结合LC低通无源滤波电路和有源滤波电路的两级输出滤波电路设计方法。通过实验,不仅实现了高压DC—DC变换器的低噪声输出,而且通过优化设计,使得两级滤波器的体积较小,可靠性较高,实现了星载应用。     

基于输出电压可调的LLC谐振变换器的设计与优化

最近谐振式变换器在消费类电子产品诸如液晶电视和等离子显示器的开关电源中得到了广泛的应用。传统的LLC谐振变换器的设计方法类似于试探法,本文给出了一种新的设计方法及设计实例,该方法可以使在输出电压范围内的额定输出电压工作在谐振点,而其他输出电压工作在谐振点附近,实验证明采用这种方法可以提高变换器的效率。