一种双不对称升压倍增单元的耦合电感Boost变换器

为了满足光伏发电并网系统对DC/DC变换器的要求和解决耦合电感变换器的电压尖峰,提出一种无电压尖峰的高升压Boost。该变换器有如下特点:采用两组不对称倍压单元,提高了变换器的升压能力,同时又消除了耦合电感二次侧绕组因续流引起的高突变电压;采用不对称倍压单元中的电容与二极管构成无源无损钳位电路,避免额外增加钳位电路,降低了成本;漏感的能量得到吸收,提高了变换器的效率;同时,降低了开关管和输出二极管的电压应力,降低了变换器对器件的要求。详细分析了变换器的工作原理,并给出了关键性的公式推到和设计依据。最后,搭建了一台200 W的试验样机,实验验证了理论的正确性,满足了电网的需求。     

一种新型低耦合双余度PMSM的设计及仿真分析

提出了一种应用于机载电动静液作动(EHA)系统的新型低耦合双余度PMSM的设计方法,分别对单余度和双余度两种工作模式下PMSM的主要性能和二维瞬态磁场进行仿真分析,重点研究了负载的起动过程及其铁心的磁饱和特性,并搭建了机载EHA系统实验平台。仿真和实验结果表明,新型低耦合双余度PMSM响应速度快、运行平稳,在降低绕组间互感的同时,完全满足机载EHA的额定性能与降额可靠性设计要求,提高了系统的控制性能。     

Design and Development of Ferroelectric Tunable Coplanar Waveguide Components for Ku- and K-Band Applications

In the past several years, we have demonstrated electrically tunable microstrip components such as resonators, filters, diplexers, and couplers based on conductor/ferroelectrics/dielectric two-layered structure. Recently, we are focusing our efforts on tunable coplanar waveguide (CPW) components in collaboration with NASA Glenn Research Center, Cleveland, OH. The advantages of CPW components include higher dielectric tunability compared to microstrip structure, ease of shunt connections, and ease of testing. To date, we have modeled several CPW structures with ferroelectric thin-film to study the effect of inserting the ferroelectric thin-film on electric tunability, attenuation and dispersion. Also, we have designed and fabricated devices such as resonators, and filters. The ferroelectric tunable CPW filters were tunable by more than 3% at bias voltage levels of - 100V. The BSTO based CPW filters offer higher sensitivity parameter as well as lower loss parameter compared to BSTO tunable 2-pole microstrip filters.     

变频变压器二次绕组的对称矢量设计与分析

采用对称矢量法对移相变压器的二次绕组进行了分析。     

宽带电光模数转换器的分析

本文对宽带电光模数(A/D)转换器进行了详细的分析.采用保角变换方法分析了转换器的带宽、损耗和特征阻抗与梯形共面波导电极参数(包括电极厚度、缓冲层厚度与中心电极和接地电极的边沿倾角β1、β2)的关系.对于梯形共面波导(中心电极宽度为8μm,电极间隔为20um,厚度为7μm,长度为8mm,β1=βg=10°)构成的A/D转换器的特征参数:带宽为6.89GHz,损耗为0.392dB/cm,特征阻抗为50.51Ω.数值仿真结果表明,采用行波干涉式调制器设计高速电光A/D转换器可以很好改善带宽对器件的性能限制.     

对称分量法的两个定理

提出并证明了对称分量法中的两个定理.它们分别是“线压对称相压无负序”和“若线压对称,则相压正序分量大小为线压的(√)1/3,相位滞后30°.”     

压缩波导隔离器设计

提出了一种压缩波导隔离器的设计结构和原理，对铁氧体样品的理论计算和实验结果完全相符，并给出了１３．５￣１３．９ＧＨｚ隔离器的实验结果和测试曲线。     

PISM-DSB原理及其应用

反相对称调制(PISM)与普通双边带(DSB)调制相结合可在同一载频上同时传输2路不同的信号,而在接收端采用2种解调方法可以分别接收到这2路不同的信号。将这一方法用于实际通信系统中会使信道利用率提高1倍。另外PISM-DSB对它台干扰也有一定的抑制作用。本文论述了这一方法的基本原理,并对它进行了计算机仿真,得到了满意的结果。     

A generalized CAD model for the full‐wave modeling of Coplanar striplines discontinuities

In this work, the coplanar stripline (CPS) and its discontinuities: open‐end, short‐end, gaps and resonator have been modeled. New integral equations for the electrical field components are formulated, in the spectral domain, using an exact dyadic Green's function, applied to the CPS structure. The use of this form of Green's function allows the consideration of the effects of the dielectric losses, the surface wave excitation and the space wave radiation on the propagation characteristics of the CPS and its discontinuities. The resulting integral equation has been solved using the two‐dimensional Galerkin's technique. The resolution of the resulting matrix equation gives the scattering parameters of the studied structures. The obtained results are commented and compared with those of other approaches and measurements. Copyright © 2011 John Wiley & Sons, Ltd.     

共面波导馈电的超宽带天线研究

设计了一种共面波导馈电的超宽带(UWB)天线,其阻抗带宽达到341%。所设计的天线印刷在尺寸为28mm×21mm×1.6mm,介电常数为2.65的聚四氟乙烯介质基板上。同时为了实现该天线与WLAN(5.725~5.825GHz)系统的协同工作,本文在共面波导的地面上刻蚀一个矩形槽,实现UWB与WLAN系统的兼容。利用高频结构仿真软件HFSS对影响天线性能的主要物理参数进行仿真、分析和优化,得到天线的优化尺寸。实验结果表明,该天线比传统微带贴片天线性能有了较大的提高,从而表明了利用共面波导馈电和刻蚀矩形槽的天线设计方法实现多种宽带通信系统兼容的可行性和有效性。     

截止波导管在腔体屏蔽中的应用研究

依据波导管的高通滤波性能,设计了一种带有波导管结构的金属屏蔽腔体.采用HFSS有限元仿真软件,分别仿真了矩形孔和加了一段矩形波导管的腔体模型,分析了在1.0～2.0 GHz频率范围内屏蔽效能和电磁场强度变化.并进一步研究了平面波不同极化方向以及波导管长度对腔体屏蔽效能的影响,得出E0沿Y轴(沿短边)极化整体屏蔽效能最好...