一种零电压开关Zeta变换器的设计

给出了一种零电压开关Zeta变换器,这种变换器可以提高效率和减小功率开关管的电压应力.当变换器工作在连续模式时,应用谐振电容和变压器的漏感实现功率开关管的零电压导通.详细分析了变换器的工作原理,并设计了相应的电路进行验证.仿真结果表明所设计的Zeta变换器效率达92.21%,输出电压纹波为125 mV.它可被用于等离子显示屏(PDP)电源系统.     

具有自驱动有源缓冲器的GaN基高效准谐振反激式功率变换器

提出了一种具有自驱动有源缓冲器的GaN基高效准谐振(QR)反激式功率变换器,以解决准谐振反激式功率变换器中开关管关断时电压过高的问题。电路以GaN高电子迁移率晶体管(HEMT)器件为主开关管和同步整流器开关管,自驱动有源缓冲器由钳位电容和有源开关管组成。该变换器在主开关管关断期间将开关管的电压浪涌钳位为恒定电压,由于有源开关管驱动信号由变压器的次级侧电流控制,因此不需要单独的控制电路。为验证所提出的变换器和控制电路的有效性,搭建了一个60 W的AC-DC功率变换器,测试结果表明,主开关管的最大电压浪涌约为450 V,具有高达91.6%的能量转换效率。     

电源与器件

手持式装置用的低压DC/DC变换器国家半导体公司的LM26XX磁性降压变换器和LM2788/98开关电容DC/DC变换器都是降压变换器解决方案。磁性降压变换器由3.3V电源供电,可提供1.8V、1.5V、1.3V或1.05V输出电压,转换效率为95％,精度为±2％;开关电容降压变换器由3.3V电源供电,可提供1.5V、1.8V和2.0V输出电压,效率为80％～90％。开关电容降压变换器具有各种标志,可告诉你     

一种新颖有源箝位ZVS正激变换器的研究

介绍了一种中心抽头全波整流有源箝位ZVS正激变换器的工作原理及主要参数计算。有源箝位电路由一个箝位开关管和箝位电容组成。变压器磁芯实现无损复位,励磁能量和漏感能量全部传递到负栽.磁芯利用率高,功率开关管承受电压应力降低。通过变压器漏感与开关管输出电容的谐振,主开关管与箝位开关管都可以实现ZVS开通,提高了变换器工作效率。文章首先分析了变换器工作原理,然后给出了主要参数的计算方法,最后通过样机(48V输入5V/20A输出)实验验证了该拓扑的高效性能。     

一种基于GaN器件的兆赫兹DC/DC变换器设计

当前中低压输入军用高可靠DC/DC电源模块普遍采用Si基功率开关,典型输入电压28 V、开关频率500 kHz,随着模块电源小型化发展、开关频率不断提升,开关损耗大幅增加,严重影响电源转换效率.软开关技术的应用可以大幅降低高频化带来的开关损耗,然而软开关控制线路结构复杂,在军用高可靠领域中目前尚无可用的高端集成控制器.GaN器件具有极低的栅电荷、输出电容以及零反向恢复电荷特性,在不增加线路复杂度的前提下可有效降低高频应用带来的开关损耗,这一点在消费电子领域AC/DC变换器中取得成功应用.然而在中低压输入军用高可靠电源模块中,随着母线电压大幅降低和开关频率的提升,GaN器件的高速特性能否有效降低开关损耗提升转换效率还有待验证.本文采用单端反激功率拓扑、同步整流技术设计了一款典型输入28 V、输出5V/30W、开关频率1 MHz的原理样机,通过对单元电路损耗的定量分析和测试验证,获得了GaN器件与Si基器件在1 MHz开关频率下的损耗与效率曲线,得出中低压高频条件下,使用GaN器件的转换效率相比Si基器件提升4%,并且功率开关的电压应力控制在合理范围内.对于军用高可靠领域中低压输入DC/D...     

一种新型单级功率因数校正AC/DC变换器的研究

文章研究了一种新型单级单开关PFC反激变换器。该变换器负载变轻时其储能电容电压不会飘升,应用于宽范围交流输入电压,储能电容电压低于450V。变换器用其变压器中的一个附加绕组实现了升压功能。由于省去了大电感,减小了变换器的体积和重量,在中小功率应用场合下,变换器符合IEC61000-3-2class D谐波标准,并且具有输出电压快速调节能力。     

多输出谐振型开关电容变换器的设计与仿真

开关电容变换器是一种典型的无感变换器,电路中主要由开关管和电容器来实现电压变换和能量转换。由于电路中不含电感和变压器,可以大大缩小电源体积、减轻重量,并且易于在芯片上集成。随着电子设备的小型化,开关电容DC-DC变换器将具有广阔的应用前景。基于开关电容DC-DC变换器的研究现状,文中系统地阐述了多输出开关电容DC-DC变换器的工作原理和设计方法,并通过系统仿真和实验验证了该类谐振型变换器的高效性。     

5V30A半桥变换式开关稳压电源

本电源采用脉冲宽度调制半桥变换式开关稳压电源,直接输入220V50Hz交流电,经整流滤波后的直流电压供给半桥变换器工作,省去笨重的50Hz电源变压器。因为半桥变换器工作在20kHz频率下,所以仅用一个较小的高频变压器就实现电压变换和输入输出的隔离。又因为功率开关管工作在开关状态,所     

推挽软开关光伏微型逆变器

为解决光伏微型逆变器对高效率、体积小、成本低的要求,研究了一种高效高增益升压推挽式隔离型电感—电容(LC)软开关串联谐振变流器。该变流器中功率开关管均能实现软开关。通过工作在升压模式下获得高输入输出增益可以有效的减少变压器匝比,提高转换效率。该变流器适用于光伏电池的能量升压转换场合。描述该变流器工作原理和电路特性,给出其拓扑结构,应用于一台试验样机光伏微型逆变器中,验证了该变流器的有效性和实用性。     

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。     

用开关电容网络改善DC-DC变换器性能的研究

将串并电容组合结构,极性反转开关电容网络和推挽开关电容网络和ｂｕｃｋ,ｂｏｏｓｔ,Ｃｕｋ及ｂｕｃｋ－ｂｏｏｓｔ等传统ＤＣ－ＤＣ变换器相结合,构成一系列新的变换器拓扑结构。理论分析和实验结果秀助于提高具有悬殊电压变化比的ＤＣ－ＤＣ变换器的工作频率和动态响应,还能拓宽变换器的电压变换范围。     

Three-Mode Dual-Frequency Two-Edge Modulation Scheme for Four-Switch Buck–Boost Converter

Four-switch buck–boost (FSBB) converter features low-voltage stress across the power switches and positive output voltage. They have two active power switches and two synchronous rectifiers, so two freedoms, i.e., the duty cycles of the two active switches, are available to regulate the output voltage. This paper proposes a two-edge modulation (TEM), in which the two active switches are trailing-edge and leading-edge modulated, respectively. Thus, the inductor current ripple can be reduced. Furthermore, a 3-mode TEM is derived to reduce the root-mean-square value of the inductor current to reduce the conduction loss. The line range is divided into three regions, and FSBB operates at boost, buck–boost, and buck modes in the lower, medium, and higher input voltage regions, respectively. At buck and boost modes, only two switches are high-frequency switched, so that the total switching loss is reduced. In the buck–boost mode, the inductor current ripple is very low compared with other two modes. Hence, the switching frequency is lowered to reduce the switching loss. The 3-mode TEM can achieve high efficiency over the line range, which is verified by a 48-V (36–75 V) input, 48-V @ 6.25-A output prototype. The measured efficiency is higher than 96.5% over the line range and the efficiency at the nominal input voltage is 97.8%.      

New topology for DC/DC bidirectional converter for hybrid systems in renewable energy

This article presents a new isolated DC/DC bidirectional converter with soft switching, using a transformer with two voltage taps and two full bridges with insulated-gate bipolar transistors (IGBTs), one on each side of the transformer to be integrated in hybrid systems of renewable energy. A large voltage conversion ratio can be achieved using this converter, in buck and booster modes. Also medium and high DC power can be converted with a good efficiency. Analysis and switching techniques have been reported. To verify the principle of operation, a laboratory prototype of 10 kW has been performed. Experimental results are presented, operating in boost mode. The switching algorithm used has been modelled in MATLAB-Simulink to generate C code. This code has been implemented in a DSP F2812, which has been used to build the prototype.     

A low noise,high power efficiency supply regulator for near-field power delivery

In order to deliver near-field electromagnetic power to a biomedical device or an RFID tag efficiently, the downlink signal is preferred to be at a high voltage level. To reduce power consumption and meet low supply requirements, it is advantageous for the remote device power supply to step-down the input voltage following rectification, typically using switch-mode regulators. The output ripple of a switched capacitor converter is inversely proportional to the filtering capacitance at the output node and switching frequency. In this paper, a hybrid DC–DC converter utilizing a switched capacitor regulator in master–slave configuration with a linear regulator is presented. Linear regulator actively cancels the switching ripple, while low frequency and DC current is provided by the switched capacitor converter. The converter is designed to receive an average input voltage of 5 Vpk from the receiver coil, with an output voltage of 2 V, and 5 mA of output current. The proposed regulator is fabricated in 0.35 μm technology. The power efficiency is measured to be 67%, with a nominal peak to peak ripple of less than 2 mV at the output.     

单片集成直流-直流转换器的效率提高方法

采用SMIC 0.13μm CMOS工艺,设计实现了开关频率达到250 MHz,单片集成的降压型电源转换器。为了提高电源转换效率,该转换器中的片上电感采用非对称性设计方法,提高了电感的品质因数。采用了高密度片上滤波电容来稳定输出电压,同时对单位电容尺寸的优化设计减小了电容的等效串联电阻以及输出电压纹波。测试结果表明,芯片输入电压为3.3 V,当输出2.5 V电压时,峰值效率达到了80%,最大输出电流达到270 mA;当输出1.8 V电压时,峰值效率达到了70%,最大输出电流达到400 mA。     

开关电容boost—buck功率因数校正组合开关变换器

文章提出了一种基于开关电容网络的boost-buck组合开关变换器,当其输入环节工作在不连续导电模式（DCM）时,具有功率因数校正（PFC）功能,详细分析了这类变换器的工作原理、临界条件、输入输出电压变比以及各器件的应力。实验结果与理论分析相符。     

Transformerless DC-to-DC converters with large conversion ratios

A novel switching DC-to-DC converter is introduced in which large voltage step-down ratios can be achieved without a very small duty ratio and without a transformer. The circuit is an extension of the Cuk converter to incorporate a multistage capacitor divider. A particularly suitable application would be a 50 V to 5 V converter in which DC isolation is not required. The absence of a transformer and a larger duty ratio permits operation at a high switching frequency and makes the circuit amenable to partial integration and hybrid construction techniques. An experimental 50 W three-stage voltage divider Cuk converter converts 50 V to 5 V at 500 kHz, with an efficiency higher than that for a basic Cuk converter operated at the same conditions. A corresponding voltage-multiplier Cuk converter is described, as well as dual buck-boost-derived step-down and step-up converters     

New series half-bridge converters with the balance input split capacitor voltages

This article presents a new dc/dc converter to perform the main functions of zero voltage switching (ZWS), low converter size, high switching frequency and low-voltage stress. Metal–oxide–semiconductor field-effect transistors (MOSFETs) with high switching frequency are used to reduce the converter size and increase circuit efficiency. To overcome low-voltage stress and high turn-on resistance of MOSFETs, the series half-bridge topology is adopted in the proposed converter. Hence, the low-voltage stress MOSFETs can be used for medium-input voltage applications. The asymmetric pulse-width modulation is used to generate the gating signals and achieve the ZWS. On the secondary side, the parallel connection of two diode rectifiers is adopted to reduce the current rating of passive components. On the primary side, the series connection of two transformers is used to balance two output inductor currents. Two flying capacitors are used to automatically balance the input split capacitor voltages. Finally, experiments with 1000 W rated power are performed to verify the theoretical analysis and the effectiveness of proposed converter.     

A Multistage Interleaved Synchronous Buck Converter With Integrated Output Filter in 0.18 μm SiGe Process

The design and analysis of a fully integrated multistage interleaved synchronous buck dc-dc converter with on-chip filter inductor and capacitor is presented. The dc-dc converter is designed and fabricated in 0.18 mum SiGe RF BiCMOS process technology and generates 1.5 V-2.0 V programmable output voltage supporting a maximum output current of 200 mA. High switching frequency of 45 MHz, multiphase interleaved operation, and fast hysteretic controller reduce the filter inductor and capacitor sizes by two orders of magnitude compared to state-of-the-art converters and enable a fully integrated converter. The fully integrated interleaved converter does not require off-chip decoupling and filtering and enables direct battery connection for integrated applications. This design is the first reported fully integrated multistage interleaved, zero voltage switching synchronous buck converter with monolithic output filters. The fully integrated buck regulator achieves 64% efficiency while providing an output current of 200 mA.     

New high power DC-DC converter with loss limited switching and lossless secondary clamp

A new isolated high frequency high power DC-DC converter full bridge topology employing one resonant "soft" switching pole that is zero voltage switched and one phase-shifted hard switching pole with loss limited switching for primary switching is presented. The devices in the loss limited pole do not have resonant capacitors across them, but exhibit significantly lower losses than conventional hard switching as the energy dissipation is limited by the finite energy stored in the leakage inductance. This unique combination of zero voltage switching and loss limited switching reduces the switching loss in all primary devices to lower levels. Isolation is achieved by a coaxially wound high frequency transformer with ultra low leakage which increases throughput and efficiency. A novel nondissipative secondary rectifier clamp allows excellent control of reverse recovery energy. Converters that produce 128 kW at 25 kHz have been developed and are commercially available. As this topology exhibits complete control of all parasitic loss mechanisms, it can be easily scaled to higher power levels.