A Design of Online Fault Diagnosis System Based on ESR for Electrolytic Capacitors

基于ESR的电解电容器在线故障诊断系统设计

¹ School of Automation, Central South University, Changsha 410075, China
² School of Traffic & Transportation Engineering, Central South University, Changsha 410075, China
³ Unique Railway Transport Technology Co., Ltd, Changchun 130000, China

Received: 21 May 2018

Abstract

ESR(Equivalent Series Resistance) is one of the important indicators for evaluating health status of electrolytic capacitors. Due to the structural specificity of the electrolytic capacitors, ESR is difficult to measure directly. In order to monitor the health status of the electrolytic capacitor in real time, an equivalent model for the electrolytic capacitor is established. The ESR frequency characteristics and temperature characteristics are analyzed and tested. The method of online fault diagnosis by evaluating the health status of the electrolytic capacitor with online calculation of ESR is proposed. Comparing the calculated value of ESR real-time with the initial value, when the former increases to a certain threshold value with respect to the latter under the same working condition, the electrolytic capacitor can be considered as failed, and the observer can perform replacement processing according to this mechanism in time. Finally, the effectiveness of the method was verified by using the dSPACE semi-physical experimental platform.

摘要

ESR（等效串联电阻）是评估电解电容器健康状态的重要指标之一，而由于电解电容器结构特殊性，ESR值很难直接测量。为了实时监测电解电容器的健康状态，建立了电解电容器等效模型，分析并测试了ESR频率特性与温度特性，提出一种通过在线计算ESR评估电解电容器健康状态以实现在线故障诊断的方法。该方法将ESR实时计算值和初始值作比较，在同等工作条件下当前者相对于后者增加至一定数值时，可认为该电解电容器已失效，观测者可根据此机理及时进行更换处理。最后通过dSPACE半实物实验平台对新方法的有效性进行了实验验证。