【作者】 薛凯峰；

【导师】 黄平；

【作者基本信息】 华南理工大学 ， 机械设计及理论， 2011， 博士

【摘要】 无线能量传输技术早在一百多年前就为人所知,但由于其传输效率偏低,未能得到广泛推广应用。近年来,随着电子技术、控制技术发展及无线能量传输需求的增加,无线能量传输技术重新得到广泛关注。无线能量传输技术在许多领域有着良好的应用前景,尤其是在生物医学领域。现有的体内微机电系统通常由化学电池组供电,主要存在供能时间短和安全性不足等问题,而无线能量传输技术为体内微机电系统提供了一种长效、稳定的供能方法。本文对国内外相关无线能量传输技术的研究成果,尤其是对该技术在生物医学领域的研究成果进行了详细的研究分析。松耦合变压器是电磁耦合感应式无线能量传输系统的核心部件,决定了系统能量传输效率和功率。现有的一维、二维无线能量传输系统能量传输效率较低,甚至存在完全无法输出能量的可能性。为克服上述缺点,本文建立了多维无线能量传输系统的数学模型及物理模型,并搭建了感应电压测试、供能等实验系统,进行了大量仿真分析与实验研究,验证了文中所提出的采用多维系统实现能量平稳传输的方法是正确、可行的。本文具体进行了以下几个方面的研究工作:1.研究了电磁感应耦合式无线能量传输技术的基本原理。利用漏感模型与互感模型对无线能量传输系统电路进行了分析,对系统的输出功率、传输效率及功率因数进行了推导与计算。2.建立了电磁感应多维耦合器数学模型,开展了多维无线能量传输系统的研究工作。首先对多维初级与一维初级两种结构的松耦合变压器进行了对比分析,随后建立了一维初级多维次级无线能量传输系统的互感数学模型,推导了多维能量传输系统初次级回路在不同补偿模式下的反映阻抗和补偿电容表达式,对初次级回路无补偿模式及初次级均采用串联模式时系统的输出功率、传输效率及功率因数进行了推导。然后,具体针对一组耦合器参数进行了计算,分析了耦合系数、线圈内阻、感抗补偿等对系统传输效率的影响。3.设计制作了多维松耦合变压器。首先,对该变压器建立了有限元仿真模型,给出了初级线圈磁场的分布,研究了次级线圈位置、姿态的改变对系统耦合系数的影响。随后,利用次级线圈感应电压实测值计算出系统耦合系数,验证了仿真分析的正确性。最后,用仿真和实验的方法对次级线圈多个绕组间的能量补偿性能进行了分析。4.设计了松耦合变压器输出多电压的整流、连接、稳压电路,制作了无线能量传输系统次级回路原理电路板,进行了能量传输实验。实验测试表明:无论次级线圈的姿态角如何变化,次级回路都可以平稳输出电压,输出功率在150mW以上,传输效率为7.08%。5.对次级电路板进行了微型化设计,制作了适用于窥视胶囊的微无线能量传输系统,完成了体内窥视胶囊总装。最后,利用该窥视胶囊进行了离体与活鸭实验,验证了本文所述的多维无线能量传输技术是合理、可行的。尽管本文就多维无线能量传输技术及其在体内窥视胶囊上的应用进行了大量研究,取得了一定成果,但仍存在一些不足,如色彩还原不足、图像清晰度欠佳,尚需后续研究克服。更多还原

【Abstract】 Wireless power transmission (WPT) technology was known more than one hundred years ago. Because of its low energy transmission efficiency, WPT was not widely used. Along with the developments of the electronic technique, the control technique and the soaring requirements for WPT in the recent years, WPT technology attracts researchers to pay attention on it again. WPT technology is expected to well apply in many areas, especially in the biomedical field. The existing MEMS inside body are usually powered by chemical battery packs. However, there are some defects caused by the energy supply model, such as limited battery life and insecurity. WPT technology may provide a stable power source for MEMS inside body.In the present dissertation, the research of WPT, especially the research results in the biomedical field are studied thoroughly. The loosely coupling transformer is the core unit of a WPT system. The transformer determines the system efficiency and output power. The efficiency of one-dimensional WPT system or two- dimensional WPT system is quite low. Sometimes these systems cannot output any power at all. In order to overcome the defects above, a multi-dimensional WPT system model is built. In addition an induced voltage measuring platform is constructed. Based on the facilities, experiments and analyses are carried on. It is indicated that the multi-dimensional WPT system developed in this dissertation is correct and feasible. The detailed work accomplished in this dissertation is as follows.First of all, the basic principles of WPT technology are studied. A leakage inductance and a mutual inductance model are introduced to analyze the energy transmission circuit. The output power and the efficiency of WPT system are given by derivation.Secondly, the mathematical model is built for the multi-dimensional WPT system. Based on the model, the reflected impedances and compensation capacitances are deduced under four different circuit structures. Moreover, the output power and the power factor are given in the following two circumstances, one is no compensation capacitor added in circuits, and the other is the compensation capacitors series connected in circuits. Then the influences of coupling coefficient k and internal resistance are studied in accordance with the loosely coupled transformer.Thirdly, a multi-dimensional loosely coupled transformer is designed and fabricated. The magnetic field distribution of the primary coil is obtained by the finite element simulation. Furthermore, influences of the secondary coil position and the attitude angle on the coupling coefficient are studied. After that, the coupling coefficients are calculated using the induced voltage values which are measured in a self-made experimental platform. The calculation results can confirm correctness of the former simulation. The compensation performances between different windings in the secondary coil are also studied by the simulations and experiments.Fourthly, a secondary coil circuit board including rectification module, multi-voltages connection module, and voltage regulation module is designed and fabricated. Using this circuit, the wireless power transmission experiment is carried on, which indicate the output voltage is stable and the output power is higher than 150mW. The efficiency of power transmission can reach 7.08%.Fifthly, the secondary coil circuit board is miniaturized. A wireless power transmission system for MEMS inside body is fabricated by using the miniaturized circuit. Afterwards, a capsule endoscope is assembled successfully. Finally, the experiments are carried on outside body and inside a live duck. The endoscope can output videos normally. The results in the dissertation indicate that the multi-dimensional WPT system is feasible.Summing up the above, much work has been done on the multi-dimensional wireless transmission technology and its application on the MEMS inside body. However, there are still some improvements needed in the future to solve the defects existing in current platform, such as the poor color reducibility and the sharpness.更多还原