A method and system for online evaluation of electrolytic capacitor state

Abstract

The invention discloses an on-line evaluation method and system for the state of an electrolytic capacitor, which realizes the purpose of on-line evaluation of the health state of the electrolytic capacitor without depending on the system structure. The method includes: obtaining the temperature characteristics of the equivalent series resistance (ESR) of a plurality of target electrolytic capacitors changing with temperature, and the frequency characteristics of ESR and impedance changing with the operating frequency, and determining the temperature characteristics of the target electrolytic capacitor according to the temperature characteristics and the frequency characteristics A fitting model of ESR changing with temperature within a specific operating frequency range; determining the initial ESR of the electrolytic capacitor to be tested according to the online operating temperature of the electrolytic capacitor to be tested and the fitting model; obtaining the electrolytic capacitor to be tested online voltage ripple and current ripple, determine the real-time ESR of the electrolytic capacitor under test according to the voltage ripple and the current ripple; evaluate the electrolytic capacitor under test according to the initial ESR and the real-time ESR state.

Description

technical field [0001] The invention belongs to the technical field of electronic component testing, and in particular relates to an on-line evaluation method and system for the state of an electrolytic capacitor. Background technique [0002] Electrolytic capacitors have been widely used in power converters such as switching power supplies, frequency converters and other systems due to their high energy density, high capacity and low price. At the same time, the electrochemical working principle also makes them one of the weakest components of the system. , Unpredictable failures may lead to the paralysis of the entire system. figure 1 Displays the percent failure rate distribution of components in a switching power supply system. Therefore, it is necessary to study the loss mechanism of electrolytic capacitors, evaluate their health status, timely and accurately predict faults and perform preventive maintenance to reduce system downtime and maintenance costs. [0003] Th...

AI Technical Summary

Problems solved by technology

Offline methods all rely on the accuracy of the measurement components, and the system where the electrolytic capacitor is located must be offline to remove the capacitor to complete the measurement, which is inconvenient to measure

However, the online method in the prior art usually depends on the system structure, and the application range is small and the implementation is complicated.

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