Alternating Current–Direct Current(AC–DC)converters require a high value bulk capacitor or afilter capacitor between the DC–DC conversion stages,which in turn causes many problems in the design of a AC–DC converter...Alternating Current–Direct Current(AC–DC)converters require a high value bulk capacitor or afilter capacitor between the DC–DC conversion stages,which in turn causes many problems in the design of a AC–DC converter.The component package size for this capacitor is large due to its high voltage rating and capacitance value.In addition,the high charging current creates more pro-blems during the product compliance testing phase.The shelf life of these specific high value capacitors is less than that of Multilayer Ceramic Capacitors(MLCC),which limits its use for the highly reliable applications.This paper presents a fea-sibility study to overcome these two problems by adding a few sensing mechan-isms to the typical AC–DC converter topology.In majority of the AC–DC converter,Al-Elko capacitor takes approximately 3%to 5%of the converter size.The proposed method reduces this to approximately 50%size and so it effectively approximates 2%to 3%size reduction in converter size.The proposed method basically works based on the load current prediction method and hence it is highly suitable for the constant load application.Moreover,the converter response time increases in this method,which limit its application in high-speed systems.The high temperature application of Al-Elko capacitor is limited because of its poor performance,which is significantly rectified by replacing the Al-Elko with MLCC as it delivers good performance in high temperature.展开更多
文中提出一种非隔离型软开关高增益准Z源DC-DC变换器。变换器具有输入电流连续、输入与输出供地、高电压增益以及开关器件应力小等优点。同时,变换器中所有开关管都工作在零电压开关(zero voltage switching,ZVS)条件下,所有二极管都工...文中提出一种非隔离型软开关高增益准Z源DC-DC变换器。变换器具有输入电流连续、输入与输出供地、高电压增益以及开关器件应力小等优点。同时,变换器中所有开关管都工作在零电压开关(zero voltage switching,ZVS)条件下,所有二极管都工作在零电压零电流开关(zero-voltage zero-current switching,ZVZCS)条件下,可以减小开关管的开关损耗以及二极管的反向恢复损耗。通过引入三耦合绕组提高变换器电压增益,同时,有源钳位电路的加入减小了开关管两端的电压尖峰。较小感值的耦合电感相应的铜损小、体积小,进而提高了变换器的效率和功率密度。深入分析变换器的工作模态,推导变换器的电压增益以及元器件的电压、电流应力,进行稳态分析和参数设计。最后,搭建一台100 kHz、200 W、38~380 V的实验样机,变换器在额定功率的效率为96.13%,实验结果与理论分析相吻合,证明所提变换器的可行性。展开更多
结合新能源混合发电要求,介绍一种三端口电气隔离、软开关运行和低输入电流纹波的三端口多向DC-DC变流器。首先通过对三绕组高频变压器的T/Δ等效变换,对5种工作模态下的功率和变压器电流有效值进行近似统一,得出全运行范围下的通用表达...结合新能源混合发电要求,介绍一种三端口电气隔离、软开关运行和低输入电流纹波的三端口多向DC-DC变流器。首先通过对三绕组高频变压器的T/Δ等效变换,对5种工作模态下的功率和变压器电流有效值进行近似统一,得出全运行范围下的通用表达式,简化了分析和降低了设计复杂度;然后对开关管的软开关运行条件进行分析,证明该拓扑具有良好的软开关特性;最后设计了一台2.5 k W的实验样机,对此变流器在宽电压输入范围条件下的工作模态和软开关特性进行实验验证,证明了理论分析的正确性。展开更多
文摘Alternating Current–Direct Current(AC–DC)converters require a high value bulk capacitor or afilter capacitor between the DC–DC conversion stages,which in turn causes many problems in the design of a AC–DC converter.The component package size for this capacitor is large due to its high voltage rating and capacitance value.In addition,the high charging current creates more pro-blems during the product compliance testing phase.The shelf life of these specific high value capacitors is less than that of Multilayer Ceramic Capacitors(MLCC),which limits its use for the highly reliable applications.This paper presents a fea-sibility study to overcome these two problems by adding a few sensing mechan-isms to the typical AC–DC converter topology.In majority of the AC–DC converter,Al-Elko capacitor takes approximately 3%to 5%of the converter size.The proposed method reduces this to approximately 50%size and so it effectively approximates 2%to 3%size reduction in converter size.The proposed method basically works based on the load current prediction method and hence it is highly suitable for the constant load application.Moreover,the converter response time increases in this method,which limit its application in high-speed systems.The high temperature application of Al-Elko capacitor is limited because of its poor performance,which is significantly rectified by replacing the Al-Elko with MLCC as it delivers good performance in high temperature.
文摘结合新能源混合发电要求,介绍一种三端口电气隔离、软开关运行和低输入电流纹波的三端口多向DC-DC变流器。首先通过对三绕组高频变压器的T/Δ等效变换,对5种工作模态下的功率和变压器电流有效值进行近似统一,得出全运行范围下的通用表达式,简化了分析和降低了设计复杂度;然后对开关管的软开关运行条件进行分析,证明该拓扑具有良好的软开关特性;最后设计了一台2.5 k W的实验样机,对此变流器在宽电压输入范围条件下的工作模态和软开关特性进行实验验证,证明了理论分析的正确性。
