为了解决感应式无线电能传输(inductive power transmission,IPT)系统容易失谐及功率难控制的问题,提出一种将能量传输过程分为能量注入和自由谐振两种工作模式的变换器拓扑结构,实现电源与谐振网络解耦,避免了电源对系统注入能量的节...为了解决感应式无线电能传输(inductive power transmission,IPT)系统容易失谐及功率难控制的问题,提出一种将能量传输过程分为能量注入和自由谐振两种工作模式的变换器拓扑结构,实现电源与谐振网络解耦,避免了电源对系统注入能量的节拍受谐振频率的约束,解决了频率跟踪难和系统失谐的问题.同时在能量注入的工作模式下,提出一种基于模态时间调节的输出功率控制方法.通过调节能量注入时间对输出功率进行控制,实现输出功率控制不受谐振网络的影响,解决了IPT系统输出功率控制难的问题.仿真和实验证明:所提出变换器工作具有合理性和可实现性;输出功率与耦合系数及负载相关性小,可通过控制能量注入时间的长短,独立地对输出功率进行控制.展开更多
[Objective] Species composition and flora of vascular plants in the middle and upper reaches of the Yarlung Zangbo River were analyzed,to provide scientific basis for the estimation and protection of plant diversity,c...[Objective] Species composition and flora of vascular plants in the middle and upper reaches of the Yarlung Zangbo River were analyzed,to provide scientific basis for the estimation and protection of plant diversity,construction of ecological security shelter for the Tibetan Plateau.[Methods] In the middle and upper reaches of the Yarlung Zangbo River,quadrat (line transect) method was applied to investigate the phytocoenoses in sample plots,and relative literature was used to analyze the floristic composition and floristic element of vascular plants in the middle and upper reaches of the Yarlung Zangbo River.[Results]① There are 96 species (including subspecies and variations),69 genera of 35 vascular plant families,accounting for 16.83%,5.48%,1.66% and 11.63%,2.02%,0.31% of total vascular plant families,genera and species in Tibet and China.② There are 24 monotypic-genus families,accounting for 68.57% of the total family number in the local area;22 monotypic-species families,accounting for 62.86% of the total family number in the local area.Local flora shows the characteristics of ancient relict,such as Euphorbiaceae,Rubiaceae,Liliaceae and Ranunculaceae,they are all ancient primitive groups of the third flora and the fourth flora.③ Local vascular plant genera fall into 10 areal types and 8 variations.④ Temperate elements are much more than tropical elements,R/T is 0.19,indicating that vascular plants have typical temperate nature and residual tropical nature.There are only a few endemic genera,but more endemic species to the local area,and these species are closely related,of which there are some transitional species,indicating that local flora is too young to experience more differentiation and specialization.⑤ There are 24 Chinese endemic species,accounting for 25% of total number of species in the local area;among which there are 12 endemic species to Tibet,accounting for 50% of endemic species to China,12.5% of total number of species in the local area.Four key wild plant species are included in the second batch of national key protection.[Conclusions]① There are scarce plant groups in the local area.② Among the obvious advantages,single-genus (species) families possess the absolute advantage,and the flora has ancient origins.③ The local flora has diversified distribution types,and the complicated geographical elements.④ Temperate species possess obvious advantages,and the flora is young.⑤ Rich unique and rare species have high species diversity protection and research value.展开更多
文摘为了解决感应式无线电能传输(inductive power transmission,IPT)系统容易失谐及功率难控制的问题,提出一种将能量传输过程分为能量注入和自由谐振两种工作模式的变换器拓扑结构,实现电源与谐振网络解耦,避免了电源对系统注入能量的节拍受谐振频率的约束,解决了频率跟踪难和系统失谐的问题.同时在能量注入的工作模式下,提出一种基于模态时间调节的输出功率控制方法.通过调节能量注入时间对输出功率进行控制,实现输出功率控制不受谐振网络的影响,解决了IPT系统输出功率控制难的问题.仿真和实验证明:所提出变换器工作具有合理性和可实现性;输出功率与耦合系数及负载相关性小,可通过控制能量注入时间的长短,独立地对输出功率进行控制.
基金Supported by National Key R&D Program of china(2016YFC0502006)Major Science and Technology Projects of Tibet(Z2016C01G01/02)
文摘[Objective] Species composition and flora of vascular plants in the middle and upper reaches of the Yarlung Zangbo River were analyzed,to provide scientific basis for the estimation and protection of plant diversity,construction of ecological security shelter for the Tibetan Plateau.[Methods] In the middle and upper reaches of the Yarlung Zangbo River,quadrat (line transect) method was applied to investigate the phytocoenoses in sample plots,and relative literature was used to analyze the floristic composition and floristic element of vascular plants in the middle and upper reaches of the Yarlung Zangbo River.[Results]① There are 96 species (including subspecies and variations),69 genera of 35 vascular plant families,accounting for 16.83%,5.48%,1.66% and 11.63%,2.02%,0.31% of total vascular plant families,genera and species in Tibet and China.② There are 24 monotypic-genus families,accounting for 68.57% of the total family number in the local area;22 monotypic-species families,accounting for 62.86% of the total family number in the local area.Local flora shows the characteristics of ancient relict,such as Euphorbiaceae,Rubiaceae,Liliaceae and Ranunculaceae,they are all ancient primitive groups of the third flora and the fourth flora.③ Local vascular plant genera fall into 10 areal types and 8 variations.④ Temperate elements are much more than tropical elements,R/T is 0.19,indicating that vascular plants have typical temperate nature and residual tropical nature.There are only a few endemic genera,but more endemic species to the local area,and these species are closely related,of which there are some transitional species,indicating that local flora is too young to experience more differentiation and specialization.⑤ There are 24 Chinese endemic species,accounting for 25% of total number of species in the local area;among which there are 12 endemic species to Tibet,accounting for 50% of endemic species to China,12.5% of total number of species in the local area.Four key wild plant species are included in the second batch of national key protection.[Conclusions]① There are scarce plant groups in the local area.② Among the obvious advantages,single-genus (species) families possess the absolute advantage,and the flora has ancient origins.③ The local flora has diversified distribution types,and the complicated geographical elements.④ Temperate species possess obvious advantages,and the flora is young.⑤ Rich unique and rare species have high species diversity protection and research value.
