共查询到18条相似文献,搜索用时 281 毫秒
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提出一种数字电路与模拟电路相结合的500kHz高频测量电路,用于微小电容的测量及小电容检测有关的断层摄影技术。 相似文献
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近年来,我国核电建设的规模不断扩大,提升核电的安全性已成为核电发展的主要趋势.电容层析成像技术是新型的检测方法,利用电容层析成像系统的构成和电容传感器的数学描述,对主蒸汽管道的两种典型流型进行仿真.检测结果表明,该方法可用于核电厂主蒸汽管道的在线监测. 相似文献
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基于ANSYS的ECT系统传感器电容值的仿真研究 总被引:1,自引:0,他引:1
电容层析成像(ECT)技术是一种新的测量技术,也是目前较为成熟的一种过程层析成像系统.该技术是用于识别一个封闭管道内两相流/多相流系统中各个相成分分布问题.它由正问题和逆问题组成,正问题中电容传感器的敏感场分布函数的计算要涉及到静电场中电容计算问题.在ECT系统的仿真研究中,电容要通过场的数值计算方法来求得.本文介绍了如何使用ANSYS来计算ECT传感器中的各电极对之间的电容.测试表明,计算结果与通过实验测量结果相吻合,该方法方便了正问题的仿真研究. 相似文献
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针对在微小电容的检测中,传统模拟电路存在设计复杂,电容测量范围小等诸多局限性这一问题,设计了一种微小电容检测系统。该系统硬件主要由电容测量芯片Pcap01、单片机STM32F103C8T6最小系统、供电电路以及LCD液晶显示屏构成。系统软件包括下位机的C程序,实现了电容数据采集、Pcap01 AD与单片机之间的通信以及数据转换。实验结果表明,该系统结构简单,精度高,误差小,稳定性好,抗干扰能力强。能方便的应用于需要微小电容检测的场合,如电容式液位传感器等。 相似文献
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针对电容层析成像(ECT)技术中的"软场"效应和病态问题,提出了一种改进的RungeKutta型landweber的电容层析成像算法。在分析ECT系统基本原理的基础上,推导出了解决电容层析成像问题的改进Runge-Kutta型landweber算法的数学模型,并采用迭代误差的单调性对算法的收敛性进行了分析。在此基础上探讨了ECT应用该算法的可行性,算法满足收敛条件且重建图像误差小。仿真和实验结果表明,该算法和LBP、landweber、最速下降法和共轭梯度算法相比,该算法兼备成像质量高、稳定性好等优点。 相似文献
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提出了一种数字电路与模拟电路相结合的500kHz高频测量电路,它用于微小电容的测量及与小电容检测有关的断层摄影技术. 相似文献
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The purpose of our research was to image the temperature distribution inside a human head by non-invasive measurement. To achieve this goal, we investigated a method for imaging the inhomogeneous permittivity distribution by measuring capacitance and to obtain the temperature distribution from the permittivity-temperature characteristic. This paper describes the first step in estimating the inhomogeneous permittivity distribution using our proposed new capacitance measurement method. We present the results of experiments performed using this method on a homogeneous phantom containing agar-agar. We estimate that the proposed method offers a practical technique for imaging inhomogeneous permittivity distributions, although some of the problems with this measurement procedure and image reconstruction system remain to be solved. © 1998 Scripta Technica. Electr Eng Jpn, 122(3): 37–45, 1998 相似文献
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基于ANSYS的传送带ECT检测技术研究 总被引:1,自引:1,他引:0
本文通过应用有限元仿真软件ANSYS进行针对30mm厚度钢芯传送带的ECT检测仿真实验,提出沿横向将传送带划分为若干段,分段检测的方法,每一段称为一个子系统,分析了仿真建模及实际设计中影响子系统性能的几个因素。实验结果说明了:仿真建模过程中应考虑到相邻子系统的影响对模型两端各扩展三个极板以保证仿真数据的准确性;电容极板与传送带之间的空隙增大将弱化子系统灵敏度;极板宽度增大可以提高子系统灵敏度;子系统沿传送带横向的长度取为60mm较为合理。优化后的传感器设计为图像重建工作奠定了良好的基础,便于监测传送带接头断裂情况。 相似文献
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This paper presents a new perturbation and observation method with a capacitance estimation technique for maximum power point tracking (MPPT) in a photovoltaic system. Usually, the maximum power point is tracked by increasing or decreasing the duty ratio of power switching devices. However, it is well known that actual capacitance of an electrolytic capacitor in parallel with a photovoltaic array has 50% tolerance of its nominal value and also that its capacitance value degrades as time passes. If the variation of the duty ratio is determined and fixed using the capacitor nominal value, the MPPT performance may be degraded. Therefore, we must use the actual capacitance in order to improve the MPPT performance. In our system, we applied the model reference adaptive system (MRAS), then obtained the accurate capacitance value and accordingly corrected the duty ratio variation. As a result, it was possible to obtain high MPPT performance. Experimental results show that the proposed method can stably track the maximum power point at widely changing capacitance values by using a newly developed buck‐boost chopper‐type power inverter. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(4): 75–85, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10150 相似文献