@article{Zhang2026, 
author = {Qinghao Zhang and Geye Lu and Tianze Meng and Pinjia Zhang},
title = {Online Thermal Monitoring Method for Converter System Based on Extraction of DC Bus Leakage Current},
year = {2026},
journal = {CSEE Journal of Power and Energy Systems},
volume = {12},
number = {3},
pages = {1608-1619},
keywords = {Converter reliabilit, IGBT, junction temperature, leakage current, online condition monitoring},
url = {https://www.sciopen.com/article/10.17775/CSEEJPES.2022.03560},
doi = {10.17775/CSEEJPES.2022.03560},
abstract = {The majority of converter failures are caused by overheating and temperature fluctuation. Therefore, online thermal monitoring methods for converters are necessary to enhance reliable operation capacity. Conventional thermal monitoring methods mainly focus on a single semiconductor device. Monitoring cost is high, and measuring circuits are difficult to integrate. Moreover, converter structure must be adjusted in industrial applications for these methods. To solve these problems, a novel online thermal monitoring method for IGBT-based converter systems is proposed. The aim is to obtain an overall temperature evaluation of the converter. First, leakage current in DC bus (IleakDC) is selected as an indicator for converter thermal monitoring. Theoretical analysis and offline experiments prove IleakDC is quasi-exponential to temperature. Then, temperature-related parameters (TCONU and TCONL) are defined corresponding to IleakDC, respectively, to characterize thermal state of converters. Next, an extraction method for IleakDC is proposed based on state-delay converter control method. Using online extracted IleakDC, a novel thermal monitoring strategy is developed. Online experiments validate effectiveness of the proposed strategy in different operating conditions. The proposed method gains advantages in low cost, easy integration, feasible and convenient implementation for system-level thermal management.}
}