0 INTRODUCTION Gas injection refers to the natural gas charging into pre-existing oil reservoirs,which often leads to notable changes in gas-oil ratio(GOR),oil density,and phase states,depending on the pressure-temper...0 INTRODUCTION Gas injection refers to the natural gas charging into pre-existing oil reservoirs,which often leads to notable changes in gas-oil ratio(GOR),oil density,and phase states,depending on the pressure-temperature condition of the reservoirs(Meulbroek et al.,1998;Blanc and Connan,1994;Evans et al.,1971).展开更多
多电平功率因子校正(power factor correction,PFC)变换器在中高压、大容量领域应用广泛。针对传统多电平拓扑使用的器件数量较多,扩展方式不明显等问题。该文以三电平钳位单元为出发点,结合多电平电路构造方法,推衍出一种基于满二叉树...多电平功率因子校正(power factor correction,PFC)变换器在中高压、大容量领域应用广泛。针对传统多电平拓扑使用的器件数量较多,扩展方式不明显等问题。该文以三电平钳位单元为出发点,结合多电平电路构造方法,推衍出一种基于满二叉树结构的新型多电平拓扑(multilevel topology based on full binary-tree structure,MT-FBT)。该型拓扑模块化程度较高、输出电平数量与扩展次数呈2的指数趋势,同时在器件数量层面较传统多电平拓扑具有一定的优势。首先,给出MT-FBT的推衍过程并归纳得到其一般形式,在此基础上阐述其扩展方式与钳位原理;然后,以MT-FBT扩展而成的四电平PFC电路为例,从工作原理、调制策略与控制方法等方面进行分析;最后,设计制作一台额定功率为1 k W的实验样机,实验结果验证了MT-FBT的可行性和所推导变换器的工程应用价值。展开更多
基金supported by the National Natural Science Foundation of China(NSFC)(No.42272169)the efficient exploration and development technologies and integrated demonstration project for deep and ultra-deep carbonate oil and gas reservoirs in the Tarim Basin(No.2025ZD1402301)+1 种基金the Integrated Project of the Joint Fund for Enterprise Innovation and Development of the National Natural Science Foundation of China(No.U24B6001)the Bureau-Level Scientific Research Project of Northwest Oilfield Company(No.KJ202501).
文摘0 INTRODUCTION Gas injection refers to the natural gas charging into pre-existing oil reservoirs,which often leads to notable changes in gas-oil ratio(GOR),oil density,and phase states,depending on the pressure-temperature condition of the reservoirs(Meulbroek et al.,1998;Blanc and Connan,1994;Evans et al.,1971).
文摘多电平功率因子校正(power factor correction,PFC)变换器在中高压、大容量领域应用广泛。针对传统多电平拓扑使用的器件数量较多,扩展方式不明显等问题。该文以三电平钳位单元为出发点,结合多电平电路构造方法,推衍出一种基于满二叉树结构的新型多电平拓扑(multilevel topology based on full binary-tree structure,MT-FBT)。该型拓扑模块化程度较高、输出电平数量与扩展次数呈2的指数趋势,同时在器件数量层面较传统多电平拓扑具有一定的优势。首先,给出MT-FBT的推衍过程并归纳得到其一般形式,在此基础上阐述其扩展方式与钳位原理;然后,以MT-FBT扩展而成的四电平PFC电路为例,从工作原理、调制策略与控制方法等方面进行分析;最后,设计制作一台额定功率为1 k W的实验样机,实验结果验证了MT-FBT的可行性和所推导变换器的工程应用价值。
