该文提出一种基于高自由度电压增益单元（high degrees of freedom voltage multiplier cell,HD-VMC）的大容量高增益DC/DC变换器,具有输入输出增益高、开关器件电压电流应力低且可调、输入相数可自由扩展且自动均流的优点。上述特性使...该文提出一种基于高自由度电压增益单元（high degrees of freedom voltage multiplier cell,HD-VMC）的大容量高增益DC/DC变换器,具有输入输出增益高、开关器件电压电流应力低且可调、输入相数可自由扩展且自动均流的优点。上述特性使得所提变换器较适用于大容量高增益直流变换场合,如海上风电直流输电系统中。文中首先对变换器的拓扑构建思路进行阐述,然后以4相输入12个HD-VMCs的变换器为例分析该变换器的工作原理及性能特点,最后通过2.5MW的仿真模型和800W的实验样机验证理论分析的正确性。展开更多
以虚拟分散控制系统(DCS)仿真控制技术和系统的相似度理论为基础,利用监控信息系统(SIS)和仿真系统的互联条件,开发了用于大型发电厂真实数据和仿真数据的比较系统。采用系统的相似度理论实现了相似度的算法,利用实时和关系数据库技术...以虚拟分散控制系统(DCS)仿真控制技术和系统的相似度理论为基础,利用监控信息系统(SIS)和仿真系统的互联条件,开发了用于大型发电厂真实数据和仿真数据的比较系统。采用系统的相似度理论实现了相似度的算法,利用实时和关系数据库技术对数据进行管理和计算,同时运用ADO(activeX data object)接口技术方便地实现了数据库和应用程序的数据连接。展开更多
为提高系统运行稳定性,高补偿度串补装置广泛投入使用,但线路故障后潜供电流存在高幅值的低频分量,潜供电弧难以自熄。针对此问题,基于交直流混联输电线路,研究了不同布置方式下串补度对潜供电流与恢复电压幅值影响,提出了一种固定串补(...为提高系统运行稳定性,高补偿度串补装置广泛投入使用,但线路故障后潜供电流存在高幅值的低频分量,潜供电弧难以自熄。针对此问题,基于交直流混联输电线路,研究了不同布置方式下串补度对潜供电流与恢复电压幅值影响,提出了一种固定串补(fixed series compensation,FSC)和可控串补(thyristor controlled series compensation,TCSC)混合复用抑制潜供电弧的方法。此外,为满足线路对高补偿度的需求,设计FSC和TCSC混合复用串补度最佳配置方案。结果表明,交直流混联线路采用串补度40%的双平台分散布置方式,潜供电流与恢复电压幅值达到最小,燃弧时间最短。高补偿度串补线路TCSC采用串补度10%、20%的配置方案更利于熄弧,提高重合闸成功率。展开更多
With the increasing quantity of DC electrical equipment, DC microgrids have been paid more and more attention. This paper proposes an approach to multi-objective optimisation of an energy management system(EMS) for a ...With the increasing quantity of DC electrical equipment, DC microgrids have been paid more and more attention. This paper proposes an approach to multi-objective optimisation of an energy management system(EMS) for a DC microgrid that includes a hybrid energy storage system(HESS). The operating and maintenance cost and the loss of power supply probability(LPSP) of the system are used as optimisation targets. The power flows of all distributed generators(DGs) in the DC microgrid during operating period are optimized. Based on the improved differential evolution(DE) algorithm, and by using the multi-objective non-dominated sorting method and the maximum membership degree principle(MMDP) of fuzzy control, the overall satisfaction degree of Pareto solutions to power flow optimization can be obtained. Simulation results verify the effectiveness of the proposed EMS optimization scheme, which is able to achieve an effective trade-off between the economy and the reliability of microgrid operation.展开更多
文摘该文提出一种基于高自由度电压增益单元（high degrees of freedom voltage multiplier cell,HD-VMC）的大容量高增益DC/DC变换器,具有输入输出增益高、开关器件电压电流应力低且可调、输入相数可自由扩展且自动均流的优点。上述特性使得所提变换器较适用于大容量高增益直流变换场合,如海上风电直流输电系统中。文中首先对变换器的拓扑构建思路进行阐述,然后以4相输入12个HD-VMCs的变换器为例分析该变换器的工作原理及性能特点,最后通过2.5MW的仿真模型和800W的实验样机验证理论分析的正确性。
文摘以虚拟分散控制系统(DCS)仿真控制技术和系统的相似度理论为基础,利用监控信息系统(SIS)和仿真系统的互联条件,开发了用于大型发电厂真实数据和仿真数据的比较系统。采用系统的相似度理论实现了相似度的算法,利用实时和关系数据库技术对数据进行管理和计算,同时运用ADO(activeX data object)接口技术方便地实现了数据库和应用程序的数据连接。
文摘伪故障特征是健康零部件振动信号中具有的故障特征,伪故障特征是由系统内故障零部件引起的。由于滚动轴承伪故障特征与故障特征具有相似性,针对转子-轴承系统中滚动轴承伪故障特征识别问题,提出一种基于经验模式分解(Empirical Mode Decomposition,EMD)和循环平稳度(Degree of Cyclostationarity,DCS)的伪故障特征识别方法。利用滚动轴承健康信号和伪故障信号对比分析基于单通道伪故障信号进行滚动轴承故障诊断的技术难点;建立了考虑滚动轴承打滑率的转子-轴承系统动力学模型;利用时频分析方法和循环平稳分析方法对滚动轴承伪故障特征进行分析;给出了基于EMD-DCS的滚动轴承伪故障特征识别流程;在滚动轴承故障模拟实验台上开展了滚动轴承伪故障特征识别实验。实验结果表明:基于EMD-DCS的滚动轴承伪故障信号识别方法可以有效区分滚动轴承故障特征与伪故障特征。该研究工作对于提高滚动轴承故障诊断准确率、保障设备安全运行具有理论意义和实际应用价值。
基金Project supported by Funds for Innovative Research Groups of China （51021005）, National Basic Research Program of China （973 Program） （2009CB724504）, National Natural Science Foundation of China（50707036）.
文摘为提高系统运行稳定性,高补偿度串补装置广泛投入使用,但线路故障后潜供电流存在高幅值的低频分量,潜供电弧难以自熄。针对此问题,基于交直流混联输电线路,研究了不同布置方式下串补度对潜供电流与恢复电压幅值影响,提出了一种固定串补(fixed series compensation,FSC)和可控串补(thyristor controlled series compensation,TCSC)混合复用抑制潜供电弧的方法。此外,为满足线路对高补偿度的需求,设计FSC和TCSC混合复用串补度最佳配置方案。结果表明,交直流混联线路采用串补度40%的双平台分散布置方式,潜供电流与恢复电压幅值达到最小,燃弧时间最短。高补偿度串补线路TCSC采用串补度10%、20%的配置方案更利于熄弧,提高重合闸成功率。
基金supported by National Natural Science Foundation of China (No. 51707045)
文摘With the increasing quantity of DC electrical equipment, DC microgrids have been paid more and more attention. This paper proposes an approach to multi-objective optimisation of an energy management system(EMS) for a DC microgrid that includes a hybrid energy storage system(HESS). The operating and maintenance cost and the loss of power supply probability(LPSP) of the system are used as optimisation targets. The power flows of all distributed generators(DGs) in the DC microgrid during operating period are optimized. Based on the improved differential evolution(DE) algorithm, and by using the multi-objective non-dominated sorting method and the maximum membership degree principle(MMDP) of fuzzy control, the overall satisfaction degree of Pareto solutions to power flow optimization can be obtained. Simulation results verify the effectiveness of the proposed EMS optimization scheme, which is able to achieve an effective trade-off between the economy and the reliability of microgrid operation.
