改进型三态开关交错并联高增益DC/DC变换器

研究了一种改进型三态开关高电压增益变换器。在输入并联-输出串联交错控制变换器基础上,将耦合电感初级引入变换器输入端,有效抑制输入电流纹波,实现输入电流自动均流的效果;两个耦合电感的次级与电容、电感构成电压倍增单元串联接入输出端,进一步提升变换器电压增益。该拓扑结构中两个串联的输出电容,既能回收再利用耦合电感的漏感能量,又能箝位开关管的漏源电压,减小开关管的电压应力,有利于选取低电压等级、低导通阻抗的开关器件,有助于减小功率管的导通与关断损耗。通过合理的漏感设计有效抑制了二极管的反向恢复问题,实现开关管零电流开关(ZCS)导通降低开关损耗。详细分析了所提变换器的工作原理与稳态工作特性,实验结果验证了理论分析的正确性。     

一种高增益交错耦合电感直流变换器

提出一种高增益交错耦合电感直流-直流升压变换器,适用于低输入电压、高输入电流的低压可再生能源发电系统应用场合,如光伏/燃料电池发电系统。该变换器在输入端把两个耦合电感的原边电流进行交错并联,减小了输入电流和输出电压纹波;两个耦合电感的副边串联后再与一电容相结合组成倍压单元,进一步提高变换器的电压增益。该电路结构中,使用两个交错串联的输出电容,它们既能回收利用耦合电感的漏感能量,又能钳位开关管的漏源电压,减小开关管电压应力,因此,有利于选择低导通电阻、高性能的开关器件以进一步减小功率管的开关和导通损耗。另外,耦合电感的漏感可使主开关管零电流开通,同时漏感也能控制二极管关断电流的下降率,大大减轻二极管的反向恢复问题。论文详细分析所提变换器的工作原理和稳态特性,最后通过一台实验样机验证了理论分析的正确性。     

交错并联磁集成开关电感高增益Boost变换器

为了提高Boost变换器电压增益、减小支路电感电流纹波、减弱开关管电压应力、减小变换器体积,提出了一种新型带有开关电感及开关电容的交错并联磁集成Boost变换器。相对于传统交错并联Boost变换器而言,利用2个开关电感单元代替储能电感,2个电容及4个二极管构成开关电容,对所提出的拓扑进行理论分析、仿真及实验验证。结果表明,在占空比0.5相似文献   

一种高增益软开关Boost-Forward变换器

提出一种高增益软开关Boost-Forward变换器。通过采用耦合电感提高了变换器的电压增益,开关管两端的并联电容限制了关断时的电压变化率,降低了关断损耗,合理设置开关驱动之间的死区,实现了开关管零电压开通。开关管的电压应力均低于输出电压,可采用低导通电阻的开关管降低导通损耗。合理设计漏感大小,解决了二极管的反向恢复问题。此外,耦合电感在开关导通和关断期间均向二次侧传递了能量,提高了耦合电感利用率。最后搭建了一台实验样机,实验结果验证了理论分析的正确性。     

一种适用于光伏并网发电系统的高增益ZVT交错并联Boost变换器

本文提出了一种新型的有源交错并联ZVT软开关电路，该电路是在普通交错并联Boost变换器的基础上增加耦合电感绕组和有源箝位辅助单元形成。耦合电感绕组的引入扩展了变换器的电压增益和减小了开关管的电压应力，因此减小了开关管导通损耗。耦合电感的漏感限制了输出二极管关断电流的下降率，抑止了二极管的反向恢复，大大减小了反向恢复电流引起的损耗。有源辅助开关和吸收电容组成的辅助电路吸收并无损的转移了漏感能量，消除了主开关管上的电压尖峰。在整个开关周期内，主管和辅助管都是零电压开关，大大减小了开关损耗。最后，设计了一台40V输入、380V输出的1kW试验样机。仿真和试验结果表明，所有的功率器件均为软开关工作，本电路特别适用于光伏发电系统中低电压输入、高电压输出的前段变换。     

带开关电容网络的交错并联磁集成电感Boost变换器

针对传统交错并联Boost变换器电压增益低、开关管电压应力高、电感电流纹波大等问题,提出一种新型交错并联Boost变换器。该变换器用2个开关电感单元分别代替储能电感L₁和L₂,并对开关电感进行耦合集成,在此基础上增加了1个二极管和2个电容构成开关电容网络。分析了变换器在不同占空比下的工作模态,推导了电压增益公式,分析了开关管电压应力和电感电流纹波的大小。与传统交错并联Boost变换器相比,该变换器性能得到明显提升,尤其在占空比D>0.5的情况下电压增益是传统交错并联Boost变换器的3（1+D）倍,开关管的电压应力减小了2/3,电感电流纹波也减小近一半。最后实验验证了理论分析的正确性。表明带开关电容网络的交错并联磁集成电感Boost变换器有着优良的工作性能。     

交错并联三绕组耦合电感高增益Boost变换器

针对光伏、燃料电池等新能源发电系统所需的高升压比的应用场景,提出一种交错并联三绕组耦合电感高增益Boost变换器。以交错并联的控制方式减小了耦合电感原边电流纹波,切分了占空比从而减少了各开关管导通时长,交错并联的开关管与输出开关管在电路结构上实现了电压钳位,不会出现电压尖峰。桥式倍压单元缓解了二极管反向恢复问题。交错并联耦合电感双原边的构造提高了变换器的工作可靠性。另外,基于该变换器还拓展出交错并联 绕组耦合电感高增益Boost变换器和n耦合电感交错并联n桥式倍压高增益Boost变换器。围绕所提变换器的工作原理及稳态性能进行了深入分析。且在理论分析的基础上通过实验平台制作了一台功率为500 W的样机验证了其准确性。     

隔离型三绕组耦合电感交错式DC/DC变换器

讨论了四种隔离型交错式DC/DC变换器结构的特点,并在交错式Flyback变换器的基础上,引入三绕组耦合电感概念,实现了Flyback型变换器到Boost型或Buck型变换器的转换.然后,在三绕组耦合电感演绎出的一次侧并联/二次侧串联Flyback-Boost变换器上,采用有源钳位软开关电路,不仅实现了主开关管和辅助开关管的零电压软开关特性,而且只需要一组钳位软开关电路就无损地吸收了两相交错电路的漏感能量、抑制了主开关管的关断电压尖峰.三绕组耦合电感的漏感限制了输出二极管关断电流的下降速率,有效地抑制了二极管的反向恢复电流.最后,设计了一台40V输入、760V输出1kW的三绕组耦合电感实现的一次侧并联/二次侧串联交错式有源钳位软开关Flyback-Boost变换器的试验样机.实验结果验证了理论分析的正确性.     

基于耦合电感与开关电容单元的高增益DC/DC变换器

提出一种基于耦合电感与开关电容单元的高增益DC/DC变换器.将开关电容单元集成到电路拓扑中,并拓展至n个,提高该变换器调节增益的自由度,使其不仅能通过改变耦合电感匝比来调节电压增益,还能通过增减开关电容单元来改变电压增益.耦合电感中漏感的电流不能突变,使得二极管的反向恢复问题得以解决.漏感能量通过无源箝位电路得到了很好的吸收,进而降低了开关管的电压应力,提高了变换器的效率和可靠性.分析了所提电路拓扑的工作原理,并对比分析了变换器的性能特点.最后,制作了一台输入电压为20～40 V,输出电压为380 V,额定功率为300 W的样机进行实验验证.主要工作波形与理论分析基本一致,且实测最高效率为95.4％,从而验证了理论分析的正确性与所提变换器的可行性.     

具有电压倍增单元的准交错并联高增益DC/DC变换器

利用耦合电感和准交错并联BOOST变换器相结合,提出了一种高增益直流变换器拓扑。由于输入采用准交错并联结构,减小了开关器件的电压应力,实现了电流扩容和纹波抑制。同时引入由耦合电感的二次侧与开关电容一起构成电压倍增单元,进一步提高了变换器电压增益。详细分析了变换器的工作过程和稳态性能,并且通过一台实验样机验证了理论分析的正确性。     

A New High Step-Up DC/DC Converter Structure by Using Coupled Inductor with Reduced Switch-Voltage Stress

In this paper, a new high step-up DC/DC converter for renewable energy systems is proposed, which provides high voltage gain by using a coupled inductor without having to have high-duty cycle and high-turn ratio. Moreover, the voltage gain increased by using capacitors charging techniques. In the proposed converter, the energy of leakage inductors of the coupled inductor is recycled to the load. This feature not only reduces stress on main switch but also increases the converter efficiency. Also, due to the configuration of the proposed structure, the voltage stress on the main switch is significantly reduced. Since the stress is low in this topology, low voltage switch with small ON-state resistance value can be used to reduce the conduction losses. As a result, losses decrease and the efficiency increases. Meanwhile, the main switch is placed in series with the source and it can control the flow of energy from source to load. The operating principles and steady-state analysis of the proposed converter are discussed in details. Finally, the prototype circuit with 12 V input voltage, 300 V output voltage, and 60 W output power is operated to verify its performance.     

ZVS DC/DC converter with series half‐bridge legs for high voltage application

This paper presents a new DC/DC converter with series half‐bridge legs for high voltage application. Two half‐bridge legs connected in series and two split capacitors are used in the proposed circuit to limit the voltage stress of each active switch at one‐half of input voltage. Thus, active switches with low voltage stress can be used at high DC bus application. In the proposed converter, two circuit modules are operated with an interleaved pulse‐width modulation scheme to reduce the input and output ripple currents and to achieve load current sharing. In each circuit module, two resonant tanks are operated with phase‐shift one‐half of switching cycle such that the frequency of the input current is twice the frequency of the resonant inductor current. Based on the resonant behavior, all MOSFETs are turned on at zero voltage switching with the wide ranges of input voltage and load conditions. The rectifier diodes can be turned off at zero current switching if the switching frequency is less than the series resonant frequency. Thus, the switching losses on power semiconductors are reduced. The proposed converter can be applied for high input voltage applications such as three‐phase 380‐V utility system. Finally, experiments based on a laboratory prototype with 960‐W rated power are provided to demonstrate the performance of proposed converter. Copyright © 2011 John Wiley & Sons, Ltd.     

Analysis,design and implementation of a high‐voltage gain DC‐DC converter

An interleaved DC‐DC converter with soft switching technique is presented. There are two converter modules in the adopted circuit to share the load power. Since the interleaved pulse‐width modulation (PWM) is adopted to control two circuit modules, the ripple currents at input and output sides are naturally reduced. Therefore the input and output capacitances can be reduced. In each circuit module, a conventional boost converter and a voltage doubler configuration with a coupled inductor are connected in series at the output side to achieve high step‐up voltage conversion ratio. Active snubber connected in parallel with boost inductor is adopted to limit voltage stress on active switch and to release the energy stored in the leakage and magnetizing inductances. Since asymmetrical PWM is used to control active switches, the leakage inductance and output capacitance of active switches are resonant in the transition interval. Thus, both active switches can be turned on at zero voltage switching. The resonant inductance and output capacitances at the secondary side of transformer are resonant to achieve zero current switching turn‐off for rectifier diodes. Therefore, the reverse recovery losses of fast recovery diodes are reduced. Finally, experiments based on a laboratory prototype rated at 400 W are presented to verify the effectiveness of the proposed converter. Copyright © 2012 John Wiley & Sons, Ltd.     

An interleaved high step‐up DC‐DC converter with double boost paths

This paper proposed a novel high step‐up converter with double boost paths. The circuit uses two switches and one double‐path voltage multiplier cell to own the double boost and interleaved effects simultaneously. The voltage gain ratio of the proposed DC‐DC converter can be three times the ratio of the conventional boost converter such that the voltage stress of the switch can be lower. The high step‐up performance is in accordance with only one double‐path voltage multiplier cell. Therefore, the number of diodes and capacitors in the proposed converter can be reduced. Furthermore, the interleaved property of the proposed circuit can reduce the losses in the rectifier diode and capacitor. The prototype circuit with 24‐V input voltage, 250‐V output voltage, and 150‐W output power is experimentally realized to verify the validity and effectiveness of the proposed converter. Copyright © 2014 John Wiley & Sons, Ltd.     

基于神经网络拟合显式MPC的高增益直流变换器

针对燃料电池、风力发电等新型能源系统输出电压较低的问题,提出一种具有拟合显式模型预测控制(model predictive control, MPC)的高增益、高效率直流变换器。该变换器具有非隔离型三绕组耦合电感基本单元结构,通过改变匝数比,在合适占空比下实现高增益,同时也降低了开关器件应力。此外,所提变换器采用无源钳位电路,回收漏感能量,抑制了开关管的电压尖峰。为了提高所提变换器的动态性能及抗扰能力,利用神经网络离线拟合显式MPC控制规律的策略,提高了输出电压跟踪精度,减小了输入电压变化和负载变化带来的扰动,具有良好的动态响应。最后在理论分析的基础上,制作出了一台输入10~12 V、输出100 V/100 W的实验样机,实验结果验证了所提变换器的有效性。     

A single‐switch cascaded high step‐up voltage converter with 95% maximum efficiency for renewable energy systems

This paper proposes a novel nonisolated single‐switch cascaded high step‐up converter. The converter consists of coupled inductors, a clamp circuit, and cascaded capacitors to achieve high step‐up voltage output. Only one switch is used in the proposed converter; the switch can reduce cost efficiently and simplify the control of the proposed converter. The converter also possesses an energy‐recycle mechanism for recycling the spike energy of a leakage inductor. In addition, a clamp circuit is used to reduce voltage‐stress across the switch, and a cascaded design is used to reduce voltage‐stress across diodes and output capacitor. Thus, the proposed converter can select a low‐voltage stress switch for reducing circuit loss and improving the efficiency of the converter. Finally, in this study, a 400‐W nonisolated cascaded high step‐up converter was implemented, of which the input and output voltages are 48 and 400 V, respectively. A microcontroller dsPIC30F4011 was used to control the converter and verify system effects and feasibility. The maximum efficiency of the proposed converter is 95% and the efficiency under a full load is 93%. Copyright © 2015 John Wiley & Sons, Ltd.     

反激式隔离型高增益DC/DC变换器

提出了一种反激式隔离型高增益DC/DC变换器.该变换器利用反激变压器的变比和开关电容来提高输出电压增益,满足输入输出的电气隔离.开关电容的引入,使得反激变压器副边绕组在开关管闭合时给倍压电容充电,在开关管断开时给负载供电,提高了变压器绕组的利用率,还解决了反激变换器输出二极管与漏感的谐振问题.由于变压器漏感的原因使得所...     

双耦合绕组反激式单级PFC变换器

提出了一种新颖的反激式单级PFC变换器拓扑.该拓扑由Boost功率因数校正(PFC)电路和具有双耦合绕组的反激变换电路组合而成,中间储能环节由两个电容构成,除了存储Boost电感能量和作为反激变换器电源之外,还分别用于吸收变压器两个初级绕组的漏感能量,因此能有效抑制功率器件的电压应力.详细分析了该变换器的工作原理和稳态特性;讨论了Boost电感和反激变压器的参数设计.实验结果表明,该变换器具有功率因数高,功率开关电压应力低,中间储能电容电压波动小等特点.     

储能用悬浮交错双向DC/DC变换器

本文提出将单向悬浮交错Boost变换器扩展到双向工作模式,得到可用于储能系统的悬浮交错双向DC/DC变换器FIBDC（floating interleaved bi-directional converter）。详细分析了该变换器在双向模式下的工作过程,推导出电压增益、功率器件承受的电压应力以及电流纹波表达式,采用共同占空比交错控制策略实现了工作电压稳定和内部子单元平衡。最后通过仿真和实验对该变换器的性能及控制策略进行验证。该变换器具有输入输出电流纹波小、电压增益高、开关管应力低以及可多相扩展等优点,适用于高压大功率场合。