结合最新雷达研制工作的需要,介绍了VHF波段中集中参数W ilk inson功率合成器的设计理论和方法,并用微波仿真软件对其进行优化。通过制作并测试该功率合成器,验证了该设计方法的可行性。同时给出了实物照片和测试数据。该功率合成器适用...结合最新雷达研制工作的需要,介绍了VHF波段中集中参数W ilk inson功率合成器的设计理论和方法,并用微波仿真软件对其进行优化。通过制作并测试该功率合成器,验证了该设计方法的可行性。同时给出了实物照片和测试数据。该功率合成器适用于VHF波段的110MHz-140MHz,峰值功率可达到6KW,可作为独立的功率合成器,也可以用作功率合成的基本单元。展开更多
The one-stream hybrid thermal network is analyzed and discussed based on the entransy theory,and the results are compared with those from the entropy generation optimization.The theoretical analysis indicates that the...The one-stream hybrid thermal network is analyzed and discussed based on the entransy theory,and the results are compared with those from the entropy generation optimization.The theoretical analysis indicates that the minimum heat-flow-weighted temperature of the thermal networks corresponds to the minimum entransy dissipation rate and the minimum thermal resistance.For a simple hybrid thermal network consisting of three thermal components,the expression of entransy dissipation is conducted,and the heat transfer area and the mass flow rate are calculated and optimized.The optimal results are obtained in order to minimize the entransy dissipation and the thermal resistance.The optimal results are calculated for various combinations,such as series connection,parallel connection and other hybrid connections.The numerical results are in accordance with the theoretical analysis.Both the theoretical analysis and the numerical results show that the minimum entransy dissipation and the minimum thermal resistance correspond to the minimum heat-flow-weighted temperature of the thermal networks while the minimum entropy generation does not.展开更多
文摘随着苏州南部电网500kV线路改造工程及10台300 MVA调相机工程的投运,该电网静/动态可靠性均得到了极大的提升,短路电流水平也随之提高。与此同时,苏州南部电网作为典型的大受端电网,其主要电源特高压锦苏直流具有季节性强的特点,导致电网存在直流换相失败风险大、直流双极闭锁后应急拉限电多等问题。加装500kV梅里—惠泉线路串联电抗器有效地控制了苏州南部电网500kV站点短路电流水平;500kV统一潮流控制器(unified power flow controller,UPFC)工程的投运显著提高了苏州南部电网对特高压交直流电网的承接能力和支撑作用。本文针对苏州南部电网在不同阶段的网架结构及UPFC发挥的作用,对串联电抗器的阻值选取进行了分析。在对串联电抗器与UPFC器协调优化的基础上,提出了既能满足短路电流控制需求,又能充分发挥UPFC潮流调节作用的串联电抗器安装阻值。
文摘结合最新雷达研制工作的需要,介绍了VHF波段中集中参数W ilk inson功率合成器的设计理论和方法,并用微波仿真软件对其进行优化。通过制作并测试该功率合成器,验证了该设计方法的可行性。同时给出了实物照片和测试数据。该功率合成器适用于VHF波段的110MHz-140MHz,峰值功率可达到6KW,可作为独立的功率合成器,也可以用作功率合成的基本单元。
基金supported by the Natural Science Foundation of China(Grant No. 51136001)the Tsinghua University Initiative Scientific Research Program
文摘The one-stream hybrid thermal network is analyzed and discussed based on the entransy theory,and the results are compared with those from the entropy generation optimization.The theoretical analysis indicates that the minimum heat-flow-weighted temperature of the thermal networks corresponds to the minimum entransy dissipation rate and the minimum thermal resistance.For a simple hybrid thermal network consisting of three thermal components,the expression of entransy dissipation is conducted,and the heat transfer area and the mass flow rate are calculated and optimized.The optimal results are obtained in order to minimize the entransy dissipation and the thermal resistance.The optimal results are calculated for various combinations,such as series connection,parallel connection and other hybrid connections.The numerical results are in accordance with the theoretical analysis.Both the theoretical analysis and the numerical results show that the minimum entransy dissipation and the minimum thermal resistance correspond to the minimum heat-flow-weighted temperature of the thermal networks while the minimum entropy generation does not.
