Multi-modular system plays an important role in power system architecture because low voltage and low power converters can be connected in any combination parallel or series at input/ output side in order to obtained ...Multi-modular system plays an important role in power system architecture because low voltage and low power converters can be connected in any combination parallel or series at input/ output side in order to obtained any given power system specifications. Multi-modular boost haft bridge DC-DC converter in the configuration of input series output parallel has been investigated in this paper. The boost half bridge DC-DC converters are connected in input series output parallel con- figuration in order to achieve equal input voltage sharing and output current sharing between the con- verters. This can be achieved with the help of dynamic control scheme which consists of two loops, a voltage loop and a current loop, for each module. Dynamic behavior of multi-modular converter configuration has been observe by varying the load condition. Moreover, the results obtained through multi-modular converter describe that the system has good dynamic and steady state response. Al- though two converter modules are focused in this paper but it can be modified to any number of modules.展开更多
The kinematic design of a reconfigurable miniature parallel kinematic machineis dealt with. It shows that the reconfigurability may be realized by packaging a tripod-basedparallel mechanism with fixed length struts in...The kinematic design of a reconfigurable miniature parallel kinematic machineis dealt with. It shows that the reconfigurability may be realized by packaging a tripod-basedparallel mechanism with fixed length struts into a compact and rigid frame with which the differentconfigurations can be formed. Utilizing a dual parameter model, the influences of the geometricalparameters on the dexterous performance and the workspace/machine volume ratio are investigated. Anovel global performance index for the dimensional synthesis is proposed and optimized, resulting ina set of dimensionless geometrical parameters.展开更多
针对传统单个逆变器驱动的无线电能传输(wireless power transfer,WPT)系统输出功率有限的问题,提出了一种多逆变器模块并联驱动的大功率WPT系统,并对多逆变器模块并联的拓扑结构和各模块间的环流进行了分析。为了解决逆变器并联时产生...针对传统单个逆变器驱动的无线电能传输(wireless power transfer,WPT)系统输出功率有限的问题,提出了一种多逆变器模块并联驱动的大功率WPT系统,并对多逆变器模块并联的拓扑结构和各模块间的环流进行了分析。为了解决逆变器并联时产生的环流问题,提出了基于主从策略的相位同步控制方法,通过从逆变器输出电压和发送端电流相位差同步于主逆变器输出电压和发送端电流相位差实现逆变器模块间的相位差补偿。研制了三个逆变器模块并联驱动的WPT系统样机,实验结果表明,在500 V直流输入时,负载端获得功率约为20 kW,传输效率达94%,且各逆变器输出电压相位实现同步,证明了相位同步控制方法的有效性。展开更多
针对现有方法控制不间断电源(Uninterrupted Power Supply,UPS)时电源运行稳定性差的问题,开展高频模块化UPS并联控制技术研究。首先建立高频模块化UPS并联运行等效电路,其次设计UPS滑模变结构控制策略,最后将比例-积分-微分(Proportion...针对现有方法控制不间断电源(Uninterrupted Power Supply,UPS)时电源运行稳定性差的问题,开展高频模块化UPS并联控制技术研究。首先建立高频模块化UPS并联运行等效电路,其次设计UPS滑模变结构控制策略,最后将比例-积分-微分(Proportional Integral Derivative,PID)控制与UPS滑模变结构控制相融合,提出一种控制技术。实例应用证明,所提技术可以显著提升电源运行动态性和稳定性,具有较大的应用价值。展开更多
随着网络规模的不断扩大,传统社区发现算法已无法有效和高效地处理大规模网络数据.基于Spark分布式图计算模型,提出大规模复杂网络社区并行发现算法DBCS(Discovering Big Community on Spark).算法利用基于模块度的聚类思想,首先计算出...随着网络规模的不断扩大,传统社区发现算法已无法有效和高效地处理大规模网络数据.基于Spark分布式图计算模型,提出大规模复杂网络社区并行发现算法DBCS(Discovering Big Community on Spark).算法利用基于模块度的聚类思想,首先计算出节点对之间的模块度增量,然后迭代查找出所有模块度增量最大的节点对,对所有节点对进行合并操作,并更新节点对之间的模块度增量,进而实现大规模复杂网络社区识别.大量真实复杂网络与仿真网络数据集上的实验结果表明:DBCS算法能有效地解决传统社区发现算法无法处理的大规模复杂网络社区划分问题,百万级以上节点处理时间约为4min,是Hadoop平台下并行发现算法运行时间的1/20,社区识别准确率比传统社区发现算法提高了7.4%.展开更多
文摘Multi-modular system plays an important role in power system architecture because low voltage and low power converters can be connected in any combination parallel or series at input/ output side in order to obtained any given power system specifications. Multi-modular boost haft bridge DC-DC converter in the configuration of input series output parallel has been investigated in this paper. The boost half bridge DC-DC converters are connected in input series output parallel con- figuration in order to achieve equal input voltage sharing and output current sharing between the con- verters. This can be achieved with the help of dynamic control scheme which consists of two loops, a voltage loop and a current loop, for each module. Dynamic behavior of multi-modular converter configuration has been observe by varying the load condition. Moreover, the results obtained through multi-modular converter describe that the system has good dynamic and steady state response. Al- though two converter modules are focused in this paper but it can be modified to any number of modules.
基金This project is supported by National Natural Science Foundation of China (No.50075059) Tianjin Science and Technology Commission (No. 99370111 andNo.003802111).
文摘The kinematic design of a reconfigurable miniature parallel kinematic machineis dealt with. It shows that the reconfigurability may be realized by packaging a tripod-basedparallel mechanism with fixed length struts into a compact and rigid frame with which the differentconfigurations can be formed. Utilizing a dual parameter model, the influences of the geometricalparameters on the dexterous performance and the workspace/machine volume ratio are investigated. Anovel global performance index for the dimensional synthesis is proposed and optimized, resulting ina set of dimensionless geometrical parameters.
文摘针对传统单个逆变器驱动的无线电能传输(wireless power transfer,WPT)系统输出功率有限的问题,提出了一种多逆变器模块并联驱动的大功率WPT系统,并对多逆变器模块并联的拓扑结构和各模块间的环流进行了分析。为了解决逆变器并联时产生的环流问题,提出了基于主从策略的相位同步控制方法,通过从逆变器输出电压和发送端电流相位差同步于主逆变器输出电压和发送端电流相位差实现逆变器模块间的相位差补偿。研制了三个逆变器模块并联驱动的WPT系统样机,实验结果表明,在500 V直流输入时,负载端获得功率约为20 kW,传输效率达94%,且各逆变器输出电压相位实现同步,证明了相位同步控制方法的有效性。
文摘针对现有方法控制不间断电源(Uninterrupted Power Supply,UPS)时电源运行稳定性差的问题,开展高频模块化UPS并联控制技术研究。首先建立高频模块化UPS并联运行等效电路,其次设计UPS滑模变结构控制策略,最后将比例-积分-微分(Proportional Integral Derivative,PID)控制与UPS滑模变结构控制相融合,提出一种控制技术。实例应用证明,所提技术可以显著提升电源运行动态性和稳定性,具有较大的应用价值。
文摘随着网络规模的不断扩大,传统社区发现算法已无法有效和高效地处理大规模网络数据.基于Spark分布式图计算模型,提出大规模复杂网络社区并行发现算法DBCS(Discovering Big Community on Spark).算法利用基于模块度的聚类思想,首先计算出节点对之间的模块度增量,然后迭代查找出所有模块度增量最大的节点对,对所有节点对进行合并操作,并更新节点对之间的模块度增量,进而实现大规模复杂网络社区识别.大量真实复杂网络与仿真网络数据集上的实验结果表明:DBCS算法能有效地解决传统社区发现算法无法处理的大规模复杂网络社区划分问题,百万级以上节点处理时间约为4min,是Hadoop平台下并行发现算法运行时间的1/20,社区识别准确率比传统社区发现算法提高了7.4%.
