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等效电路模型是研究电介质介电响应的有效手段,其反映的是实际介电响应与由代表弛豫过程、电导过程的电气单元构成的电路之间的关系.在等效电路模型中所有可能的电气单元种类包括:1)弛豫峰型介电响应单元;2)低频弥散介电响应单元;3)电荷扩散单元;4)频率无关电容单元;5)直流电导单元.需要根据电介质的微观结构的实际物理意义以及实际的测量条件来选择等效电路模型中相应的电气单元以及单元之间的电气连接方式.在计算等效电路模型的具体参数时,需要在拟合中同时考虑复电容的实部和虚部.同一种电介质,测量的条件不同会导致所测量获得的介电响应和相应的等效电路模型也不同.判断等效电路模型是否合理需从物理实际角度和数学拟合角度两个方面进行判断,不能仅仅为了提高等效电路模型对实际介电响应的拟合程度而随意添加没有实际弛豫过程或电导过程对应的电气单元.等效电路模型分析可以对实际电介质介电响应进行定量的表征,这为深入分析外界条件、组分含量等因素对电介质介电响应以及对电介质微观结构的影响提供了分析方法和理论依据.该文以分析电气绝缘领域常见的硅橡胶材料和树脂材料的介电响应为例,详细讨论了分析实际电介质介电响应时构建等效电路模型的方法以及判断所选等效电路模型是否合理的依据.“,”The use of equivalent circuit is an effective method to investigate the measured dielectric response data. The equivalent circuit represents the measured dielectric response data using discrete electrical components representing relaxation and conductivity processes. There are five types of electrical components that can be inserted in an equivalent circuit: 1) a loss peak component;2) a quasi-dc component (QDC);3) a charge diffusion component;4) a frequency independent capacitance component;5) a dc conductivity component. The types of electrical components and their electrical connections in the circuit (in series or in parallel) should be determined by a comprehensive consideration of the actual physical meaning of the microscopic structure of the dielectric and the actual measurement condition. In calculating the specific parameters of the equivalent circuit, it is necessary to consider simultaneously the real and imaginary parts of the complex capacitance. For a given dielectric material, different measurement conditions, such as electrode configuration, measurement temperature, etc, can change the measured dielectric response and hence alter the corresponding equivalent circuit used for the data fitting. The rationale for using a particular equivalent circuit should be determined from both physical and mathematical point of view. Electrical components without clear physical meaning should not be inserted in the equivalent circuit only for the purpose of improving the accuracy of the fit. The equivalent circuit method represents a quantitative analysis of the dielectric response and provides a basis for theoretical understanding of the factors influencing the response: external conditions, microscopic structure of dielectric, etc. The dielectric response of HTV silicone rubber and epoxy resin are analyzed using equivalent circuits. The method of constructing the equivalent circuits and the rationale for using specific components in the circuits are explained in detail. Some issues related to the application of the equivalent circuit method are outlined.