Capacitance prediction method of metallized film capacitor
A technology of metallized film and prediction method, which is applied in the direction of instruments, electrical digital data processing, calculation, etc., can solve the problem of not being able to accurately obtain more actual performance information of capacitors, and achieve easy comparative analysis, high accuracy, and strong practicability Effect
Active Publication Date: 2019-12-17
HUAZHONG UNIV OF SCI & TECH
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Problems solved by technology
[0004] The invention provides a method for predicting the capacitance of metallized film capacitors, which is used to solve the problem that in the prediction of the capacitance of the existing metallized film capacitors, the absolute value of the capacitance cannot be accurately obtained based on the absolute value of the capacitance. Technical issues with current actual performance information
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Embodiment 1
[0045] A capacitance prediction method 100 for a metallized film capacitor, such as figure 1 shown, including:
[0046] Step 110, setting the sample capacitor in an environment with preset temperature and humidity;
[0047] Step 120, measure the initial capacitance of the sample capacitor, and measure the capacitance once every time the capacitor works for a preset period of time, calculate the capacitance change of the capacitance relative to the initial capacitance until the capacitance change reaches the preset value, and obtain Total working time and multiple capacitance changes;
[0048] Step 130, based on all capacitance changes, fit the relationship curve between capacitance changes and time under multiple time periods, wherein the sum of multiple time periods is the total working time;
[0049] Step 140 , based on the actual service time and initial capacitance of the capacitor under test, select the corresponding relationship curve and predict the current capacitanc...
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The invention discloses a capacitance prediction method of a metallized film capacitor. The method comprises the following steps: setting a sample capacitor in a preset temperature and humidity environment; measuring the initial capacitance of the sample capacitor, measuring the capacitance once after the capacitor works for a preset period of time, and calculating the variation of the capacitancerelative to the initial capacitance until the total working duration reaches a preset duration; based on all the capacitance variations, fitting to obtain a relation curve of the capacitance variations and time in multiple stages; and based on the actual use duration of the capacitor to be measured, selecting the corresponding relation curve and predicting to obtain the current capacitance of thecapacitor to be measured. According to the invention, the relative variation of the capacitance is obtained based on the initial value, and the drop conditions of different capacitors can be comparedand analyzed. The relation curve fitted by stages not only can accurately predict the capacitance, but also can judge the residual working life. Therefore, the current performance information of various capacitors can be acquired while high-precision capacitance prediction is realized, and the practicability is high.
Description
technical field [0001] The invention belongs to the field of capacitor capacitance, and more particularly relates to a method for predicting the capacitance of a metallized film capacitor. Background technique [0002] Metallized film capacitors can be used in safety capacitors, connected between the live wire and the neutral wire of the AC circuit, used to suppress the differential mode interference of the power supply, or used in the resistance-capacitance step-down power supply in series with the AC circuit. Metallized film capacitors as safety capacitors encounter three main risk factors during their working process: continuous AC working voltage, high temperature, and high humidity. Studies have shown that there are two main mechanisms for the capacitance loss of metallized film capacitors: (1) self-healing of the metallized film; (2) electrode oxidation caused by electrochemical corrosion. Due to the long-term working requirements for metallized film capacitors, the w...
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Inventor 李化李征林福昌刘毅张钦王燕
Owner HUAZHONG UNIV OF SCI & TECH