针对利用双向感应耦合电能传输(Inductively Coupled Power Transfer,ICPT)系统的能量通道实现信号交互传输时产生信号与系统输出电压间的互扰谐波问题,采用双LCC谐振补偿网络,基于串联注入拾取式的频移键控信号载波调制方式,给出一种双...针对利用双向感应耦合电能传输(Inductively Coupled Power Transfer,ICPT)系统的能量通道实现信号交互传输时产生信号与系统输出电压间的互扰谐波问题,采用双LCC谐振补偿网络,基于串联注入拾取式的频移键控信号载波调制方式,给出一种双向ICPT系统能量与信号同步传输方法.选取4 MHz和5 MHz的低频载波信号和高频载波信号,采用状态空间模型及交流阻抗法分析能量与信号之间互扰问题,利用Matlab/Simulink仿真平台搭建双向ICPT系统能量与信号同步传输仿真模型.仿真结果表明,系统可实现最大效率的能量双向传输以及信号的零误码率传输,信号与能量在同步传输时互扰较小,通过系统波特图的分析验证了选取频率点的有效性.展开更多
Previous studies focused on the bed load transport rate for the condition of turbulent flow,while the knowledge of sediment transport in laminar flow is very limited.As an extreme case to reflect the viscous effect on...Previous studies focused on the bed load transport rate for the condition of turbulent flow,while the knowledge of sediment transport in laminar flow is very limited.As an extreme case to reflect the viscous effect on sediment transport,sediment transport in laminar flow is considered in this paper.There are at least two factors affecting the transport rate of sediment under laminar flow conditions: (1) fluid forces;(2) particle to particle interactions.Together,these two factors represent the physical transport system.First,an exposure degree Probability Density Function (PDF) is developed to explore how the transport rate can be associated with characteristics of laminar flow and this factor reflects the particle to particle interactions,and the pickup probability equation in the absence of turbulence is developed based on the stochastic approach which reflects the exposure degree influence.Then,the formulas to calculate the critical shear stress of incipient motion and the bed load transport rate of fine uniform sediment are established.The derivation is made mainly based on Einstein’s bed load theory;we choose Einstein’s equation to model this system because we believe that the probabilistic approach taken is an appropriate way to account for the spatial and temporal variations in the forces causing sediment transport.These formulas have been tested against a wide range of existing laboratory data and compared with other existing empirical or semiempirical methods.The predictions by these newly proposed formulas are very good.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 50739002 and 50979064)
文摘Previous studies focused on the bed load transport rate for the condition of turbulent flow,while the knowledge of sediment transport in laminar flow is very limited.As an extreme case to reflect the viscous effect on sediment transport,sediment transport in laminar flow is considered in this paper.There are at least two factors affecting the transport rate of sediment under laminar flow conditions: (1) fluid forces;(2) particle to particle interactions.Together,these two factors represent the physical transport system.First,an exposure degree Probability Density Function (PDF) is developed to explore how the transport rate can be associated with characteristics of laminar flow and this factor reflects the particle to particle interactions,and the pickup probability equation in the absence of turbulence is developed based on the stochastic approach which reflects the exposure degree influence.Then,the formulas to calculate the critical shear stress of incipient motion and the bed load transport rate of fine uniform sediment are established.The derivation is made mainly based on Einstein’s bed load theory;we choose Einstein’s equation to model this system because we believe that the probabilistic approach taken is an appropriate way to account for the spatial and temporal variations in the forces causing sediment transport.These formulas have been tested against a wide range of existing laboratory data and compared with other existing empirical or semiempirical methods.The predictions by these newly proposed formulas are very good.
