排序方式: 共有56条查询结果,搜索用时 619 毫秒
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针对厦门鹭岛±320kV柔性直流换流站示范工程中IGBT升温导致热失效甚至损坏问题,设计了IGBT子模块集成FBG传感器实时监测并调整其工作状态的方案,分析了MMC运行机理,设计了温度传感器结构,研究了监测系统对IGBT失效的预防方案。依据仿真分析结果,设计并搭建了用于实时监测IGBT温度分布系统,实验室工况环境下在线运行并对数据进行分析,结果表明:系统运行稳定,实时监测IGBT工作状态,温度分辨率优于0.1 ℃,证明该系统稳定可靠,符合工程应用要求,该测温系统将用于厦门鹭岛柔性直流换流站工程中,为换流站的安全运行提供保障。 相似文献
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皮下组织血氧参量是反映皮瓣移植术后皮瓣存活状况的重要依据。为了无创、连续、实时地监测皮肤组织氧饱和度,采用近红外光谱法进行了理论分析和实验验证,提出了一种电流-电压(I-V)转换思路并搭建了测量系统。利用该系统进行了稳定性验证实验、前臂静脉阻断模拟皮瓣血管栓塞实验。结果表明,不同人体、不同部位的组织氧饱和度存在微小差异,差异幅度均在0.05左右;静脉阻断下系统组织氧参量发生显著改变,最大降幅0.25。该系统具有较高灵敏度,能够连续测量组织氧饱和度参量、反映组织氧变化趋势,可以为临床检测术后皮瓣血氧运输状态提供重要参考。 相似文献
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研究了基于保偏光纤的光纤环镜结构并建立理论模型,分析各参数之间的关系,设计并搭建了基于偏振干涉的保偏光纤环镜传感解调系统.以LabVIEW作为软件平台,依据理论模型,开发了光纤光栅传感嚣解调控制系统,不仅实现了对解调系统的远程控制、数据采集、图形化显示及数据存储,节省了成本,还能直接获得待测参量值.采用可调谐激光器模拟光纤光栅反射波长的变化,实验证明了该解调方案的可行性和正确性.温度传感检测实验表明,该系统对温度的测量平均精度可达0.03℃,准确度为±0.01℃.Abstract: The loop mirror structure based on the polarization-maintaining fiber was investigated, the corresponding theoretical model was established, and the relations of these parameters are also analyzed. The sensor demodulation system of the polarization-maintaining fiber loop mirror based on polarization interference was designed and established. Using LabVIEW as the software platform, the demodulation control system for the fiber grating sensor was developed based on the theoretical model, realizing the remote control of the demodulation system, diagrammatic display and data acquisition and storage. With this scheme, the cost is reduced and the measured parameters can be directly obtained. The fluctuation of the reflection wavelengths of the fiber grating was simulated with the tunable laser, and the feasibility and validity of this scheme were confirmed by experiments. Detection experiments with temperature sensors show that the average temperature measuring precision can be up to 0.03 ℃ and the accuracy is ±0.1 ℃. 相似文献
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基于保偏光纤的高精度光纤光栅传感解调方案 总被引:2,自引:1,他引:1
提出一种基于线偏振光干涉原理的无源波长解调系统.在普通光纤环镜中引入双折射效应.光纤环镜的反射(透射)光强足耦合器分光比K、温度t、保偏光纤长度L和两端偏振方向夹角的函数.在单调区间内反射(透射)光强与t存在对应关系.通过测定光强口可求得t.利用矩阵光学原理建立理论模型,研究了保偏光纤长度、耦合器耦合系数、偏振光入射夹角对光纤环镜(FLM)反射(透射)光强与入射光波长关系影响的特性,设计了基于保偏光纤环镜的分辨率可控的干涉型解调仪.用自制光纤光栅作为传感头监测温度变化,数据显示该系统对温度的测量平均精度可达0.03℃,准确度±0.1℃. 相似文献
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The generation of optical millimeter waves via the improved phase modulator in a RoF system and the transmission character of the signal are theoretically investigated. A new phase modulating scheme is proposed, in which the sidebands are separated by wave length demultiplexer and one of them doesn't feed digital signals, thereby the phase wake-off is restrained. 相似文献