Novel topologies for DC-DC converter with PWM control

Two topologies for the buck converter are presented. The first converter consists of two active switches whereas the second converter, derived from the parent twoswitch converter, consists of only one active switch. The main feature of this new converter is the ability to operate at a constant switching frequency using a simple PWM control. The design of the gate circuit is simplified as there is only one switch. The converter has a good efficiency, as is proved by the experimental results. The operation of the parent two-switch converter, from which the new single-switch converter is derived, is also presented to gain insight into the design of the new converter.     

采用有源电容倍增器改善开关电容DC-DC变换器的性能

研究了开关电容DC-DC变换器输出电压与电容的关系,分析了变换器输出电压波纹产生的原因.针对变换器中大电容难集成的问题,提出了一种基于跨导放大器和第二代电流传输器的有源电容倍增器的新型拓扑结构.该电路只用较少的元件就可以实现开关电容变换器中的浮地和接地电容.以二阶开关电容DC-DC变换器为例,用PSPICE软件分别对采用了有源电容倍增器的新型结构和传统结构进行了仿真.结果显示,基于有源电容倍增器的开关电容变换器仅用100pF电容就等效了200nF电容的输出性能,而且具有更低的输出电压波纹.     

Watkins-Johnson converter completes tapped inductor converter matrix

The Watkins-Johnson converter has been identified as belonging to the tapped inductor converter families extending once more the matrix of DC-DC converter topologies. This converter is analysed in terms of the tap position and the switch duty cycle and its operation as a rail-to-tap buck converter is verified.     

基于LM5025的有源箝位反激变换器的前馈控制

在有源箝位反激变换器负载基本恒定的情况下采用前馈控制既可以减小变换器体积,又可降低变换器的成本。文中在分析有源箝位反激变换器工作原理的基础上,结合LM5025器件的前馈控制特性,深入研究了基于LM5025的有源箝位反激变换器前馈控制的实现方案,设计了前馈控制电路的参数,完成了有源前馈反激变换器电路设计。在此基础上进行了实验研究,实验结果证明了有源箝位反激变换器前馈控制的有效性和实用性。     

矩阵变换器的间接空间矢量控制

矩阵变换器是一种新型的电力电子技术,具有能量可双向流通,可产生正弦输入电流和输出电压以及输入功率角可调等优点。文章基于矩阵变换器空间矢量调制法,分析虚拟整流器和逆变器的空间矢量调制,综合两个过程,得到一种直接的交-交变换器,利用MATLAB的仿真模块组建成矩阵变换器的仿真模型。仿真结果验证了空间矢量调制策略的有效性,矩阵变换器的优越性。     

A zero-current-switched off-line quasi-resonant converter withreduced frequency range: analysis, design, and experimental results

A half-bridge zero-current-switched (ZCS) offline quasi-resonant converter (QCR) operating in full-wave mode is implemented to reduce the modulation frequency range due to load variations. The design and characteristics of the converter are described and compared with their half-wave counterpart in frequency range, component stress, and efficiency. An experimental converter which delivers output power from 10 to 100 W with a modulation frequency from 700 kHz to 1.4 MHz is presented. The converter showed superior transient response compared to the corresponding half-wave converter. The efficiency of the full-wave converter at full-load was several percent lower than that of the half-wave converter and decreases at a much faster rate as the output power decreases     

一种设计光栅扫描雷达显示器坐标转换器的新方法

分析了光栅扫描雷达显示器的几种常用坐标变换器电路,提出了一种性能优良的“改进的存贮器法”坐标转换器电路,论述了其实现方法。     

On configurable oversampled A/D converters

An oversampled A/D (analog-to-digital) converter that can be configured as either a sigma-delta converter or an incremental converter is presented. This is an oversampled instrumentation converter that cancels offset and 1/f noise. The converter architecture is based on a mixed analog-digital integrator (MADI) concept. This concept is shown to lead to a very simple and modular architecture. The implemented converter also allows selection of the converter order and the decimation factor in order to find the best tradeoff between resolution, conversion time or bandwidth, and power consumption. As the converter architecture is completely modular, it can rapidly be tailored for a specific application with minimized silicon area. The circuit achieves a resolution of 16 b on a range of ±650 mV and compensates the offset and the even-order harmonics to a nonobservable level     

Transformer secondary leakage inductance based ZVS dual bridge DC/DC converter

A novel zero voltage switching (ZVS) dual bridge dc/dc converter is presented. The proposed converter is composed of two dual-transistor-forward converter, coupled with a single high frequency transformer. ZVS is realized by introducing a proper leakage inductance to the secondary of the high frequency isolation transformer with a corporation of a designed pulse-width modulation control. Operation principle and ZVS condition of the proposed converter are analyzed. Experimental results obtained from a 3.2-kW prototype are given. Extensions of the proposed converter topologies and experimental results of one extension converter are presented.     

PWM-controlled SRC with inductive output filter at constantswitching frequency

By using the PWM control scheme in the series resonant power converter (SRC) with inductive output filter, the converter can be operated at a constant frequency. This converter has lower switching loss than the PWM converter and better control characteristics than the ordinary SRC. Since the peak current in the present converter equals the load current, it has the lowest possible peak current stress among converters. The analysis and the performance characteristics of the converter operating at a constant switching frequency are presented. Experimental results are given to confirm the analytical work     

矩阵变换器双空间矢量控制法的仿真研究

矩阵变换器与普通交-直-交变换器相比有一些优异的性能。目前,在矩阵变换器的调制算法中,双空间矢量算法最为成熟,基于该调制法的矩阵变换器是交-交变换器研究中最具潜力应用于生产的理想变换器。文中论述了空间矢量法的原理,分析了双空间矢量调制策略,在Matlab/Simulink仿真平台上搭建了矩阵变换器模型并进行了仿真,以简单的阻感负载作为供电对象。仿真结果验证了双空间矢量调制策略的正确性和可行性,较明显地看出矩阵变换器与一般电力变换器相比的优点,也显示了矩阵变换器应用于工程实际的可行性。     

Vacon变频器在提升机低频制动系统上的应用

本文介绍了矿井提升机制动要求,提出用低压变频器控制高压电机设计方案。低压变频器用于控制提升机实现低频制动时,需要控制变频器输出电压实现转矩控制,本文设计了P I D控制器,实现变频器的输出电压控制。给出了变频器低频制动控制系统结构,介绍了变频器软件程序的设计。试验结果表明,此低频制动系统具有较好的控制效果。     

主从控制模式下并联Buck变换器的均流技术研究

文中建立了主从均流控制下的并联Buck变换器的数学模型.从动态特性上来说,保留了主变换器的原有设计特性,从变换器强制改变原有的特性,跟随主变换器电流.同时还研究了基于UC3842模块下的主从控制均流现象,并分析两者的特性.     

Smart Internet of Things (IOT) System for Performance Improvement of Dual Bridge LLC Resonant Converter by Using Sophisticated Distribution Control Method (SDC)

A resonant converter is a kind of electric power converter that contains a system of inductors and capacitors called a resonant tank, tuned to resonate at a particular frequency in this work recommends a better-quality dual bridge LLC resonant converter with a novel controller technique. The resonant converters include the serial or parallel connections of inductors and capacitors to activate the switch to realize the Zero Current Switching (ZCS) and Zero Volt Switching (ZVS) under resonance conditions. The resonant effects are switching sufferers, turning strain and electromagnetic interference problems the switching resonant converter controls the output voltage through changing frequency and generally can be sub classified in ZCS converter and ZVS converter. This scheme had combined wireless monitoring for dual bridge LLC resonant converter for dc distribution applications based on sophisticated distribution controller (SDC) through the internet of things and embedded structure access and other mechanisms. The consequence of our exhibition demonstrates that the framework can monitor and store the manipulate data from the converter. Thus, the wireless monitoring functions are realized in real-time. This converter permits both forward and reverses power exchange between the source and the load, to keep up the output voltage consistent, regardless of load and line unsettling influences, it is important to work the converter as a closed loop system. The proposed SDC based dual bridge resonant converter has validated through simulation in Matlab Simulink environment. A hardware setup is also developed to validate the simulation. General 97% effectiveness accomplished at full load condition in light of the dual bridge resonant converter.     

A novel single-stage half-bridge AC-DC converter with high powerfactor

A new single-stage AC-DC power converter based on a half-bridge converter suitable for low-power applications is proposed. The proposed converter offers high power factor and direct conversion from the line voltage to an isolated DC output voltage. High power factor is achieved by adding a resonant circuit between the rectifying diodes and half-bridge leg. For soft switching, a half-bridge series-loaded resonant converter is adopted as a DC-DC converter part. A prototype is built and tested to show the validity of the proposed converter     

基于耦合电感的四相交错Buck变换器研究

基于耦合电感的四相交错Buck变换器是由4个同步Buck变换器通过磁耦合技术并联组成。在分析其工作原理、软开关条件以及设计耦合电感的基础上,以TMS320F28035作为控制核心,搭建了一台16 kW的实验样机。实验结果表明,该变换器在移相（PS）PWM控制策略下,开关管电流应力小,电流纹波明显减小,可在全负载范围内实现零电压开关（ZVS）,适用于低压大电流、大功率应用场合。     

An isolated bridgeless AC-DC PFC converter using a LC resonant voltage doubler rectifier

This paper proposed an isolated bridgeless AC–DC power factor correction (PFC) converter using a LC resonant voltage doubler rectifier. The proposed converter is based on isolated conventional single-ended primary inductance converter (SEPIC) PFC converter. The conduction loss of rectification is reduced than a conventional one because the proposed converter is designed to eliminate a full-bridge rectifier at an input stage. Moreover, for zero-current switching (ZCS) operation and low voltage stresses of output diodes, the secondary of the proposed converter is designed as voltage doubler with a LC resonant tank. Additionally, an input–output electrical isolation is provided for safety standard. In conclusion, high power factor is achieved and efficiency is improved. The operational principles, steady-state analysis and design equations of the proposed converter are described in detail. Experimental results from a 60 W prototype at a constant switching frequency 100 kHz are presented to verify the performance of the proposed converter.     

Quasi-multi-pulse voltage source converter design with two control degrees of freedom

In this article, the design details of a quasi-multi-pulse voltage source converter (VSC) switched at line frequency of 50 Hz are given in a step-by-step process. The proposed converter is comprised of four 12-pulse converter units, which is suitable for the simulation of single-/multi-converter flexible alternating current transmission system devices as well as high voltage direct current systems operating at the transmission level. The magnetic interface of the converter is originally designed with given all parameters for 100 MVA operation. The so-called two-angle control method is adopted to control the voltage magnitude and the phase angle of the converter independently. PSCAD simulation results verify both four-quadrant converter operation and closed-loop control of the converter operated as static synchronous compensator (STATCOM).     

低损耗软开关Boost变换器

介绍一种新的软开关Boost变换器。传统的Boost变换器在开通和关断时将产生开关损耗,因此使整个系统的效率下降。新的Boost变换器利用软开关方法增加了辅助开关管和谐振电路。这样,相比硬开关情况下,变换器减小了开关损耗。这种变换器可以应用在光伏系统、功率因子校正等装置中。详细分析电路的工作原理以及实现软开关的条件,利用Pspice9．2软件进行仿真验证。仿真结果表明,该变换器的所有开关器件都实现了软开关,从而使效率得到提高。     

Integrated Cuk-forward converter for photovoltaic-based LED lighting

An integrated Cuk-forward converter for a photovoltaic (PV)-based light emitting diodes (LED) lighting system is presented. In this converter, the Cuk converter delivers the solar energy via PV cell modules to a battery bank in charging mode during the daytime. However, the zero voltage switching (ZVS) forward converter drives the LED lighting system in discharging mode during the night time. Power switches in the Cuk converter and ZVS forward converter are integrated to reduce the component count and the synchronous switch is used in the circuit to reduce the conduction losses and increase the circuit efficiency. Thus, the advantages of the proposed converter are smaller size, lighter weight, fewer components and higher efficiency. Experimental results based on the laboratory prototype rated at 200 W are presented to verify the effectiveness of the proposed converter.