Measurement method of parasitic inductance of capacitor

Abstract

The invention relates to a measurement method of parasitic inductance of a capacitor, which comprises the following steps: selecting two plates with identical length width and thickness which are made of the same conductive material as a test electrode; dividing the test electrodes into an upper layer and a lower layer to be arranged on an outer electrode of the capacitor to be detected, and to be respectively and electrically connected with the anode and the cathode of the outer electrode of the capacitor to be detected; electrically connecting the two test electrodes and two input ends of a test instrument; and measuring the parasitic inductance of the capacitor in a conventional discharging way. The two test electrodes are arranged in a superimposing way, so the influence of the stray inductance and the equivalent resistance on the test electrode part in an external circuit is small, and the measurement precision of the parasitic inductance of the capacitor is improved.

Description

technical field [0001] The invention relates to a method for measuring the parasitic inductance of a capacitor. Background technique [0002] Power electronic capacitors are widely used in rail transit, high-speed trains, medium and high voltage inverters, etc. These fields have particularly stringent requirements on the performance of the required capacitors. Capacitor parasitic inductance is an important indicator of its performance. If the parasitic inductance of the capacitor is large, the DC bus voltage of these devices will increase, and at the same time, an overvoltage will be generated on the control core component insulated gate bipolar transistor (IGBT), which may cause damage to the insulated gate bipolar transistor or equipment failure. . Based on the above reasons, many equipment manufacturers require the parasitic inductance of the capacitor to be less than 50-100nH. However, some large companies such as GE, Alstom, and BCP require that the parasitic inducta...

AI Technical Summary

Problems solved by technology

The disadvantage is that the stray inductance L of the external test electrode copper strip itself exists 1 , L 2 And other factors, the error of the test inductance is relatively large, and the error inductance is about 20nH, which affects the judgment of the actual parasitic inductance of the capacitor under test, especially when the user has strict requirements on the parasitic inductance of the capacitor, and the parasitic inductance of the capacitor is required to be lower than 30nH In this case, this test method obviously cannot meet the requirements

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