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基于小波分析理论的电磁兼容测试与诊断技术研究
Study on Electromagnetic Compatibility Test and Diagnosis Technology Based on Wavelet Analysis Theory
【作者】 陈曦;
【作者基本信息】 河北工业大学 , 电机与电器, 2001, 博士
【摘要】 电磁兼容(EMC)是以电磁场理论为基础,包括信息、电工、电子、通讯、材料、结构等多学科交叉的,研究在有限空间、时间和频谱资源条件下各种电器、电子设备或系统在同一电磁环境中相互兼容,而不致引起其性能下降的应用科学技术。国际上对电磁兼容的研究十分重视,一些发达国家和地区将电磁兼容纳入到国家法律体系中,在经济上形成了贸易壁垒。 电磁兼容的研究范围很广泛,研究问题十分复杂,电磁兼容测试技术是其中重要的研究方向与研究热点。 电磁兼容测试技术主要包括测量设备、测量方法、数据处理方法以及测量结果的评价等,电磁干扰EMI测试研究的理论基础是Fourier分析,本文通过电磁干扰信号特征分析以及Fourier分析数学原理指出了电磁干扰EMI测试中Fourier分析的局限性。电磁干扰信号的时间特性,也是反映电磁骚扰源的重要信息,如骚扰源的起始时间、持续时间、不同骚扰源在不同时刻可能包含着不同频率等等。在上述情况下,本文阐述了用时间-频率方法分析电磁干扰信号的有效性,论证了用小波理论分析进行电磁兼容性测试与诊断的可行性,并给出了多分辨率小波分析和正交小波分析在电磁干扰信号EMI诊断中的仿真研究和实例研究,证明了小波分析方法在电磁兼容性测试与诊断中有效性。 本文还结合典型家用电器产品的电磁兼容试验,提出了典型家用电器电磁兼容的一些共性技术问题,给出了抗干扰对策,并以变频空调器为例,剖析了家用电器中广泛使用的变频装置产生的电磁兼容问题。
【Abstract】 Electromagnetic Compatibility (EMC) is a cross-disciplinary science based on electromagnetism including such multi-disciplinary as information science, electrical engineering, electronics, communications, materials and structures, etc. It is also an applied technology, which is used to study, under the conditions of limited space, limited time and limited frequency resources, the compatibility of electrical and electronic devices and systems within the common electromagnetic enviroment without a degradation of performance. The international society attachs importance to the EMC and some developed countries and regions bring it into the state抯 law system, thus forming a trade bulwark. The study range of EMC is very extendsive and the problem of EMC is very complex. The EMC testing technology is one focus of the EMC research field. The EMC testing technology includes testing equipment, testing method, data processing and result evaluation. The Fourier analysis is the foundation theory of electromagnetic interfere (EMJ) testing study. According to the characteristics of EMI signal and mathematics principle of Fourier analysis, this paper explains the localization of Fourier analysis method in the EMI testing. The time characteristics of EMI testing signal is a useful imformation of electromagnetic disturbance source also, such as starting time, duration time, and the different frequency of electromagnetic disturbance source in the different time. Under condition above, this paper points out the validity of a time-frequency analytic method and demonstrates the feasibility of an EMI diagnosis based on wavelet analysis theory. Some EMI diagnosis simulation results and case study resulting from multi-resolution wavelet analysis and wavelet packet analysis are also given in this paper, which proves that wavelet analysis method is of validity. This paper brings forward some common technological problems about typical household appliances?EMC according to EMC testing, and gives some countermeasures use to anti-interfere in the typical household appliances. An EMC problem due to a PWM inverter applied in air-condition is analyze carefully.