A method and system for evaluating the health of DC bus capacitors in traction converters

Abstract

The invention discloses a method and system for evaluating the health of the DC bus capacitor of a traction converter. The steps of the method are as follows: first step, synchronous sampling and acquisition of the DC bus voltage of the traction converter, the three-phase output current of the inverter module, and the power switch The switching signal of the tube; the second step is to calculate the ESR and C at the switching frequency of the DC bus capacitor and the output frequency of the inverter module respectively according to the switching signal and the three-phase output current of the inverter module; the third step is to calculate according to the surface temperature of the DC bus capacitor and the The three-phase output current of the inverter module and the switching signal estimate the center temperature of the DC bus capacitor; the fourth step is to evaluate the health status of the DC bus capacitor based on the DC bus capacitor and the ESR and C at the output frequency, combined with the center temperature. The method provided by the invention can utilize the original sampling points in the traction converter, can accurately monitor the ESR and C at two frequencies of the DC bus capacitor of the traction converter, and effectively evaluate the health status of the DC bus capacitor.

Description

technical field [0001] The invention relates to the field of on-line monitoring and reliability evaluation of power electronic components, in particular to a method and system for evaluating the health of a DC bus capacitor of a traction converter. Background technique [0002] With the improvement of power supply management standards for high-speed electrified railways and passenger dedicated lines, higher requirements are placed on the safety and reliability of power supply equipment. As far as the current electrical equipment management methods of China's electrified railways are concerned, it will cost a lot of operation to meet the standard requirements. maintenance costs. Therefore, necessary equipment monitoring measures must be taken to reduce the hidden dangers of power supply system accidents, reduce the probability of accidents, shorten the time for fault finding and maintenance, ensure the reliable operation of the power supply system, and play a role in reducing...

AI Technical Summary

Problems solved by technology

However, most of the current studies use the surface temperature as a reference, and there is an error between the surface temperature and the central temperature, so the confidence in the current assessment of capacitor health is not high

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