隔离三电平零电压直流变换器

介绍了一种隔离三电平零电压直流变换器。其主开关管的电压应力均为输入电压的一半。由于采用了交错ZVSPWM控制并利用输出滤波电感中的能量,因此能够在宽负载范围内实现开关管的ZVS。分析了该变换器的工作原理和工作特性,并通过一个480W（输出48V／10A）的原理样机进行了验证,最后给出了实验结果。     

基于LTC3789的DC/DC变换器设计

为将宽输入范围直流电压变换成稳定直流电压输出,以控制器LTC3789为核心,高速、高频、低损耗MOSFET器件为控制开关,采用恒定频率的电流控制模式,设计了一款能够实现宽范围输入电压同步、无缝、高效的升压-降压DC/DC变换电路,并进行了物理实验验证。实验结果表明,所设计的以LTC3789为控制核心的电路能够实现6-30V直流输入,12.8V稳定直流输出的DC/DC变换,并且电路工作稳定、可靠。     

具有提升直流环节稳态电压功能的单相全桥 谐振直流环节逆变器

为改善直流电压利用率,提出了一种具有提升直流环节稳态电压功能的单相全桥谐振直流环节软开关逆变器,利用辅助电路中的变压器可以将电能补充到直流母线上等效为电压源的钳位电容,使直流环节稳态电压高于直流电源电压,提高了逆变器输出线电压的基波幅值和直流电压利用率.文中分析了电路的工作状态.在4kW样机上的实验结果表明逆变器的主开关和辅助开关能完成软切换.因此,该拓扑结构对于研发高性能谐振直流环节逆变器具有一定的借鉴意义.     

Zero-voltage DC/DC converter with asymmetric pulse-width modulation for DC micro-grid system

This paper presents a zero-voltage switching DC/DC converter for DC micro-grid system applications. The proposed circuit includes three half-bridge circuit cells connected in primary-series and secondary-parallel in order to lessen the voltage rating of power switches and current rating of rectifier diodes. Thus, low voltage stress of power MOSFETs can be adopted for high-voltage input applications with high switching frequency operation. In order to achieve low switching losses and high circuit efficiency, asymmetric pulse-width modulation is used to turn on power switches at zero voltage. Flying capacitors are used between each circuit cell to automatically balance input split voltages. Therefore, the voltage stress of each power switch is limited at V_in/3. Finally, a prototype is constructed and experiments are provided to demonstrate the circuit performance.     

A novel ZVS DC/DC converter for high power applications

This paper presents a novel zero voltage switch (ZVS) pulse-width modulation (PWM) DC/DC converter for high power, high output voltage applications. By using two active switches in the secondary side of a transformer, the proposed converter achieves not only ZVS of the active switches in the entire load ranges but also soft commutation of the output rectifier diodes. The proposed topology has simple structure and control strategy. Simulation results and experimental results of a 2.8 kW 200 kHz DC/DC converter are presented.     

Dual-coupled inductor-fed DC/DC converter for battery drive applications

A new isolated boost DC/DC converter suitable for a low-input-voltage application is introduced. The proposed converter features low switch current stresses, wide range of input voltage, and inherent inrush current protection, essential for the design of a low-to-high-voltage conversion circuit. A comparative analysis and experimental results are presented to show the validity of the proposed converter.     

基于DC/DC变换的逆变技术的研究

传统逆变器结构简单、技术成熟,但由于自身拓扑结构的不足使其存在开关损耗大、输出滤波要求高、输出交流幅值受电源电压限制、开关状态转换时可能出现直通短路等缺点。基于Buck的DC/DC变换器由于本身拓扑结构的优势,有效避免了传统逆变器的这些问题,进一步提高了效率。简要介绍了现有基于DC/DC变换器的逆变电路拓扑,并分析了各自拓扑结构的优缺点及相应的控制方式。     

DC/DC转换器中电流采样电路的设计

设计了一种用于DC/DC开关电源转换器的新型电流采样电路.常见的电流采样电路是通过检测采样管串联电阻上压降来得到采样电流,而该采样电路是通过检测开关管串联电感上压降来得到采样电流的.由于后者所需电阻更少,从而降低了采样电路的功耗,提高了效率;并且由于电感上压降对采样电流变化的灵敏度更高,有效地提高了采样的精度.     

电动汽车隔离型DC/DC辅助电源模块的可靠性设计

提出一种新型的电压前馈补偿的准谐振、零电流开关DC/DC变换器电路设计方案,并对DC/DC辅助电源模块电路拓扑结构的进行论证和选择,运用电磁兼容性(EMC)设计方法,研制并开发电动汽车用隔离型DC/DC辅助电源模块。     

Steady-state analysis and design of a buck zero-current-switchingresonant DC/DC converter

An analytic basis is provided for a buck high-efficiency high-frequency zero-current-switching resonant DC/DC power converter. The current and voltage waveforms are derived for the steady-state operation. Design equations are then introduced for the switch duty cycle, maximum switching frequency, DC transfer function, peak currents and voltages, output power, and power conversion capability. Finally, the design procedure is presented along with the advantages and disadvantages of the converter, which are discussed in detail     

节能型谐振直流环节逆变器

为改善逆变器的运行效率,提出了一种节能型三相谐振直流环节软开关逆变电路,在直流环节增设了辅助电路.当主开关需要切换时,提前使辅助电路进入谐振状态,将直流环节电压变化到零,保证主开关完成零电压软切换,并且辅助开关也能完成软切换.通过控制辅助开关切换的间隔时间来调节直流环节电压保持为零的时间,使逆变器能根据需要来调整脉宽调制策略.详细说明了电路的工作过程.实验结果表明逆变器主开关和辅助开关能完成软切换.因此,该拓扑结构对于研发高性能谐振直流环节逆变器具有借鉴意义.     

Dual sepic PWM switching-mode DC/DC power converter

A steady-state analysis and experimental results for a dual sepic pulse-width-modulated (PWM) DC/DC power converter for both continuous and discontinuous modes of operation are presented. The converter is dual to a sepic converter, but it can also be derived from a forward converter by replacing one of its rectifier diodes with a coupling capacitor. The circuit acts as a step-down or step-up converter, depending on the value of the ON switch duty cycle. The transformerless version of the converter has a positive DC/DC voltage transfer function. Therefore, the circuit is suitable for distributed power systems. Design equations for all circuit components are derived. Experimental results measured at 100 kHz were in good agreement with theoretical predictions     

A new modulation strategy for a buck-boost input AC/DC converter

This paper presents a novel modulation strategy for a power factor corrected (PFC), isolated AC/DC converter derived from the integration of a nonisolated, two switch buck-boost AC/DC converter with an isolated dual active bridge DC/DC converter (2SBBDAB). This strategy, termed discontinuous leading/trailing edge (DLTE) modulation, serves to maximize the duty cycle of the input switch while keeping the current in the buck-boost inductor discontinuous. Hence, the crest factors of the currents in the switching devices are minimized, the input switch is turned on at zero current and the zero-voltage switching ranges of the bridge switches are unaffected by the integration. A conventional isolated, PFC AC/DC converter typically consists of a boost converter cascaded with a forward converter. The ratings required of the power switching devices of the 2SBBDAB employing the DLTE modulation strategy are similar to those required of the conventional design for wide line voltage operation. However, the 2SBBDAB converter has higher line voltage surge immunity than that of the conventional design and, unlike the conventional design, it has inherent inrush current limiting. The DLTE modulation strategy may be applied to the family of converters composed of the two switch buck-boost integrated with half and full-bridge forward converters     

一种新型DC/DC变换器实验系统开发

为强化DC/DC变换技术的实践教学,基于多绕组变压器和反激电路原理,开发一套DC/DC变换器教学系统。设计变换器的拓扑结构,分析工作原理及控制策略,计算变换器系统参数,建立数字仿真模型,设计变换器主电路、输出电压采样电路、开关管驱动电路等来搭建变换器实验平台。实验教学应用表明,该变换器实现宽输入/输出电压范围功能的同时,能够提高学生的电力电子技术综合实践能力。     

Voltage and current stress reduction in single-stage power factorcorrection AC/DC converters with bulk capacitor voltage feedback

Single-stage power factor correction (PFC) AC/DC converters integrate a boost-derived input current shaper (ICS) with a flyback or forward DC/DC converter in one single stage. The ICS can be operated in either discontinuous current mode (DCM) or continuous current mode (CCM), while the flyback or forward DC/DC converter is operated in CCM. Almost all single-stage PFC AC/DC converters suffer from high bulk capacitor voltage stress and extra switch current stress. The bulk capacitor voltage feedback with a coupled winding structure is widely used to reduce both the voltage and current stresses in practical single-stage PFC AC/DC converters. This paper presents a detailed analysis of the bulk capacitor voltage feedback, including the relationship between bulk capacitor voltage, input current harmonics, voltage feedback ratio, and load condition. The maximum bulk capacitor voltage appears when the DC/DC converter operates at the boundary between CCM and DCM. This paper also reveals that only the voltage feedback ratio determines the input current harmonics under DCM ICS and CCM DC/DC operation. The theoretical prediction of the bulk capacitor voltage as well as the predicted input harmonic contents is verified experimentally on a 60 W AC/DC converter with universal-line input     

直流开关电源的欠压浪涌抑制技术

针对开关电源在欠压浪涌中存在的诸多问题,分析了瞬态欠压浪涌的工作机理、抑制方法,以及由此引起的负载端启动电流或浪涌电压的处理思路,给出了处理直流开关电源欠压浪涌的合理解决方案。     

Analysis and design of class E isolated DC/DC converter using classE low dv/dt PWM synchronous rectifier

A class E isolated DC/DC power converter for regulating the output voltage at a fixed switching frequency is presented, analyzed and experimentally verified. It consists of class E series-resonant inverter, high-frequency transformer and class E low dv/dt pulse width modulation (PWM) synchronous rectifier. By controlling the conduction time of the controlled switch in the rectifier, high-frequency AC current is rectified and the output voltage can be controlled at the same time. The zero voltage switching (ZVS) condition of all switches can be maintained from full-loaded to open-loaded. The theoretical predictions were in good agreement with the experimental measurements and the maximum efficiency measured at a switching frequency of 1 MHz was 91.2%     

一种高效开关电容AC—DC变换器

针对开关电容ＤＣ－ＤＣ变换器的效率会随着输入电压的增高而显著下降的现象，提出了一种新型的基于开关电容网络的ＡＣ－ＤＣ变换器，它采用根据输入电压变化而动态确定功率开关的导通和关断的方法，从原理上解决了开关电容ＤＣ－ＤＣ变换器的输入电压动态范围与变换器效率之间的矛盾。理论分析和实验结果表明，该转换器可以在较宽的输入电压范围获得较高的转换效率。     

Performance of MCT's in a current-regulated AC/DC PDM converter

An AC/DC current-regulated pulse density modulated (PDM) power converter is presented. The MOS-controlled thyristor (MCT) is used in this power converter because of its promising advantages over existing power devices. A unique bidirectional switch configuration is used, which allows the MCT to switch easily at zero voltage. The converter performance is evaluated driving a 5 hp induction motor. MCT switching was performed satisfactorily, but the device fails before its ratings are reached. The MCT will be better than other devices when used in applications that require critical timing and high voltage blocking capability     

基于电荷泵的低压启动高效率Boost DC/DC变换器设计

设计了一种在供电电源电压稍高于MOS管阀值的超低压条件下就能正常工作的宽输入电压范围的DC/DC变换器。电荷泵的启动模块和Boost升压模块集成于同一芯片中,在电压低于2.2V（typical）时,芯片包括两部分的工作过程,首先由电荷泵的启动模块使电压升高至2.2V,然后由输出电压为Boost转换器模块供电,使芯片正常工作。输入电压高于2.2V时,只有Boost模块工作。为使芯片实现高效率的转换,在轻载情况下,采用PFM调制模式;在重载情况下,采用PWM调制模式;通过逻辑控制两种模式自动切换,实现了良好的负载调整率。芯片采用SMIC 0.5um CMOS工艺设计并流片测试,在0.83V的电源电压时,芯片能正常启动工作。在电压VIN=1.2V,VOUT=3.3V时,最大效率达到87%,所有电压和负载范围内效率不低于50%。该芯片可用于单电池供电的系统中。