针对感应式电能传输(inductive power transfer,IPT)系统偏移造成输出电压不稳定和效率低下的问题,提出一种强抗偏移的S/SP补偿IPT系统,该系统在变耦合变自感和变耦合不变自感两种情况下均能保证较小的输出电压波动和较高的传输效率。首...针对感应式电能传输(inductive power transfer,IPT)系统偏移造成输出电压不稳定和效率低下的问题,提出一种强抗偏移的S/SP补偿IPT系统,该系统在变耦合变自感和变耦合不变自感两种情况下均能保证较小的输出电压波动和较高的传输效率。首先,基于Maxwell有限元仿真,分析罐型磁心松耦合变压器的磁通分布和磁场分布特性,总结不同方向偏移的参数变化规律。然后,提出一种提高系统抗偏移能力的S/SP补偿参数设计方法,得到相应的磁耦合机构设计准则,并结合磁仿真数据,通过数值计算方式求得系统输出波动和输入阻抗角的变化规律。最后,通过实验验证文中采用罐型磁心和新型S/SP补偿拓扑实现多方向偏移下高效率、低波动无线电能传输的可行性。在额定负载下,系统沿纵向和水平方向偏移的输出电压波动分别为2.7%和3.1%,传输效率维持在90.8%~94.3%。展开更多
基波等效法是无线电能传输(wireless power transfer,WPT)技术的主要研究方法,该方法将整流性负载的基波阻抗等效为某一纯电阻,为系统的建模和分析提供基础。但该方法忽略整流性负载谐波阻抗的影响,使WPT系统的实际响应与理论分析结果...基波等效法是无线电能传输(wireless power transfer,WPT)技术的主要研究方法,该方法将整流性负载的基波阻抗等效为某一纯电阻,为系统的建模和分析提供基础。但该方法忽略整流性负载谐波阻抗的影响,使WPT系统的实际响应与理论分析结果存在较大的误差,从而影响系统的模型精度,限制WPT系统的进一步优化设计。该文以基于串/串并(series/series-parallel,S/SP)补偿网络的WPT系统为研究对象,分析利用基波等效法进行建模产生误差的原因,并提出一种基于迭代法的整流性负载基波以及各次谐波等效阻抗的精确计算方法。在此基础上,建立WPT系统的精确电路响应模型,所提模型可以有效表征发射线圈电流的畸变特性,并根据系统响应与补偿网络参数的关系获得系统逆变器开关损耗的优化设计方法。最后,搭建一台3kW的WPT系统样机,实验结果验证理论分析的正确性和可行性。展开更多
It is the matter for achievement of the low carbon transport system that the excessive use of private vehicles can be controlled appropriately.Not only improvement of service level of modes except private vehicle,but ...It is the matter for achievement of the low carbon transport system that the excessive use of private vehicles can be controlled appropriately.Not only improvement of service level of modes except private vehicle,but also consciousness for environmental problem of individual trip maker is important for eco-commuting promotion.On the other hand,consciousness for environment would be changed by influence of other person.Accordingly,it is aimed in the study that the structure of decision-making process for modal shift to the eco-commuting mode in the local city is described considering environmental consciousness and social interaction.For the purpose,the consciousness for the environment problem and the travel behavior of the commuter at the suburban area in the local city are investigated by the questionnaire survey.The covariance structure about the eco-consciousness is analyzed with the database of the questionnaire survey by structural equation modeling.As the result,it can be confirmed with the structural equation model that the individual environmental consciousness is strongly related with the intention of self-sacrifice and is influenced with the local interaction of the individual connections.On the other hand,the intention of modal shift for the commuting mode is analyzed with the database of the questionnaire survey.It can be found out that the environmental consciousness is not statistically significant for commuting mode choice with the present poor level of service of public transport.However,the intention of self-sacrifice for the prevention of the global warming is statistically confirmed as the factor of modal shift with the operation of eco-commuting bus service with the RP/SP integrated estimation method.As the result,the multi-agent simulation system with social interaction model for eco consciousness is developed to measure the effect of the eco-commuting promotion.For the purpose,the carbon dioxide emission is estimated based on traffic demand and road network condition in the traffic environment model.On the other hand,the relation between agents is defined based on the small world network.The proposed multi-agent simulation is applied to measure the effect of the eco-commuting promotion such as improvement of level of service on the public transport or education of eco-consciousness.The effect of the promotion plan can be observed with the proposed multi-agent system.Finally,it can be concluded that the proposed multi-agent simulation with social interaction for eco-consciousness is useful for planning of eco-commuting promotion.展开更多
In orthogonal frequency division multiplexing(OFDM) based muitihop communications,the conventional decodeand-forward(DF) relay scheme severely suffers from the error propagation problem.This drawback is serious in mui...In orthogonal frequency division multiplexing(OFDM) based muitihop communications,the conventional decodeand-forward(DF) relay scheme severely suffers from the error propagation problem.This drawback is serious in muitihop networks as errors made by any relay node may fail the decoder at the destination in great chance.In this paper,we propose a bit error rate(BER)modified DF protocol(BMDF) which can be applied to systems where error correction channel coding and M-ary modulation are used.By modeling all links except the last one as a binary symmetric channel(BSC),we derive a log likelihood ratio(LLR)modification function relying only on the accumulated BER of all previous links to be applied to the output of the soft demapper.Furthermore,to reduce the computational complexity and signaling overhead,the modification function is simplified from its original exponential expression and less BERs are delivered between nodes by making successive subcarriers share the same BER.In addition,for situations where the channel state information(CSI) of forward link is available,the proposed BMDF can be further enhanced by combining with subcarrier pairing(SP) and power allocation(PA),where a sorted-channel gain SP scheme and a greedy PA algorithm are proposed.The simulation results verify the significant performance improvement to the conventional DF.展开更多
该文将移动Ad Hoc网络多播路由协议作为主要研究内容——基于树的多播路由协议MAODV(Multicast Ad Hoc On-De-mand Distance Vector Routing Protocol)。针对目前MAODV协议存在可扩展性、健壮性差的问题,该文提出了一种新的优化改进协议...该文将移动Ad Hoc网络多播路由协议作为主要研究内容——基于树的多播路由协议MAODV(Multicast Ad Hoc On-De-mand Distance Vector Routing Protocol)。针对目前MAODV协议存在可扩展性、健壮性差的问题,该文提出了一种新的优化改进协议MAODV-SP(MAODV With Stable Path),主要从两个方面对MAODV协议进行了扩展改进。首先在多播树建立方面,MAODV-SP协议采用了基于邻居变化率稳定路径选择机制,根据不同路径上各节点的邻居变化率累乘值,选择转发跳数小且局部拓扑变化小的稳定路径进行数据转发。其次在多播树维护方面,MAODV-SP协议采用了基于链路状态预测链路可用性机制,对节点的移动性和链路状况进行预测,在预测到链路断链即将发生之前,重新选择一条新的有效路由转发分组,使网络的性能达到最优。展开更多
文摘针对感应式电能传输(inductive power transfer,IPT)系统偏移造成输出电压不稳定和效率低下的问题,提出一种强抗偏移的S/SP补偿IPT系统,该系统在变耦合变自感和变耦合不变自感两种情况下均能保证较小的输出电压波动和较高的传输效率。首先,基于Maxwell有限元仿真,分析罐型磁心松耦合变压器的磁通分布和磁场分布特性,总结不同方向偏移的参数变化规律。然后,提出一种提高系统抗偏移能力的S/SP补偿参数设计方法,得到相应的磁耦合机构设计准则,并结合磁仿真数据,通过数值计算方式求得系统输出波动和输入阻抗角的变化规律。最后,通过实验验证文中采用罐型磁心和新型S/SP补偿拓扑实现多方向偏移下高效率、低波动无线电能传输的可行性。在额定负载下,系统沿纵向和水平方向偏移的输出电压波动分别为2.7%和3.1%,传输效率维持在90.8%~94.3%。
文摘基波等效法是无线电能传输(wireless power transfer,WPT)技术的主要研究方法,该方法将整流性负载的基波阻抗等效为某一纯电阻,为系统的建模和分析提供基础。但该方法忽略整流性负载谐波阻抗的影响,使WPT系统的实际响应与理论分析结果存在较大的误差,从而影响系统的模型精度,限制WPT系统的进一步优化设计。该文以基于串/串并(series/series-parallel,S/SP)补偿网络的WPT系统为研究对象,分析利用基波等效法进行建模产生误差的原因,并提出一种基于迭代法的整流性负载基波以及各次谐波等效阻抗的精确计算方法。在此基础上,建立WPT系统的精确电路响应模型,所提模型可以有效表征发射线圈电流的畸变特性,并根据系统响应与补偿网络参数的关系获得系统逆变器开关损耗的优化设计方法。最后,搭建一台3kW的WPT系统样机,实验结果验证理论分析的正确性和可行性。
基金The research is granted by Japanese Ministry of Education as a part of Grants-in-Aid for Scientific Research,No.(C)22560533.The author records here warmest appreciation to the Resident Conference for Environment of Tokushima Prefecture for collecting the data in the field of actual travel behavior on the social experiment.
文摘It is the matter for achievement of the low carbon transport system that the excessive use of private vehicles can be controlled appropriately.Not only improvement of service level of modes except private vehicle,but also consciousness for environmental problem of individual trip maker is important for eco-commuting promotion.On the other hand,consciousness for environment would be changed by influence of other person.Accordingly,it is aimed in the study that the structure of decision-making process for modal shift to the eco-commuting mode in the local city is described considering environmental consciousness and social interaction.For the purpose,the consciousness for the environment problem and the travel behavior of the commuter at the suburban area in the local city are investigated by the questionnaire survey.The covariance structure about the eco-consciousness is analyzed with the database of the questionnaire survey by structural equation modeling.As the result,it can be confirmed with the structural equation model that the individual environmental consciousness is strongly related with the intention of self-sacrifice and is influenced with the local interaction of the individual connections.On the other hand,the intention of modal shift for the commuting mode is analyzed with the database of the questionnaire survey.It can be found out that the environmental consciousness is not statistically significant for commuting mode choice with the present poor level of service of public transport.However,the intention of self-sacrifice for the prevention of the global warming is statistically confirmed as the factor of modal shift with the operation of eco-commuting bus service with the RP/SP integrated estimation method.As the result,the multi-agent simulation system with social interaction model for eco consciousness is developed to measure the effect of the eco-commuting promotion.For the purpose,the carbon dioxide emission is estimated based on traffic demand and road network condition in the traffic environment model.On the other hand,the relation between agents is defined based on the small world network.The proposed multi-agent simulation is applied to measure the effect of the eco-commuting promotion such as improvement of level of service on the public transport or education of eco-consciousness.The effect of the promotion plan can be observed with the proposed multi-agent system.Finally,it can be concluded that the proposed multi-agent simulation with social interaction for eco-consciousness is useful for planning of eco-commuting promotion.
基金The authors would like to thank National Natural Science Foundation of China （No. 61072059）.
文摘In orthogonal frequency division multiplexing(OFDM) based muitihop communications,the conventional decodeand-forward(DF) relay scheme severely suffers from the error propagation problem.This drawback is serious in muitihop networks as errors made by any relay node may fail the decoder at the destination in great chance.In this paper,we propose a bit error rate(BER)modified DF protocol(BMDF) which can be applied to systems where error correction channel coding and M-ary modulation are used.By modeling all links except the last one as a binary symmetric channel(BSC),we derive a log likelihood ratio(LLR)modification function relying only on the accumulated BER of all previous links to be applied to the output of the soft demapper.Furthermore,to reduce the computational complexity and signaling overhead,the modification function is simplified from its original exponential expression and less BERs are delivered between nodes by making successive subcarriers share the same BER.In addition,for situations where the channel state information(CSI) of forward link is available,the proposed BMDF can be further enhanced by combining with subcarrier pairing(SP) and power allocation(PA),where a sorted-channel gain SP scheme and a greedy PA algorithm are proposed.The simulation results verify the significant performance improvement to the conventional DF.
文摘该文将移动Ad Hoc网络多播路由协议作为主要研究内容——基于树的多播路由协议MAODV(Multicast Ad Hoc On-De-mand Distance Vector Routing Protocol)。针对目前MAODV协议存在可扩展性、健壮性差的问题,该文提出了一种新的优化改进协议MAODV-SP(MAODV With Stable Path),主要从两个方面对MAODV协议进行了扩展改进。首先在多播树建立方面,MAODV-SP协议采用了基于邻居变化率稳定路径选择机制,根据不同路径上各节点的邻居变化率累乘值,选择转发跳数小且局部拓扑变化小的稳定路径进行数据转发。其次在多播树维护方面,MAODV-SP协议采用了基于链路状态预测链路可用性机制,对节点的移动性和链路状况进行预测,在预测到链路断链即将发生之前,重新选择一条新的有效路由转发分组,使网络的性能达到最优。
