A fiber bragg grating sensing system for monitoring IGBT temperature distribution and thermal conduction state of upper surface silicone

IGBT is a high-power device used in the field of power electronics. Its internal temperature rise will lead to module failure, which will seriously affect the safe operation of high-voltage converter systems. At present, mature methods used in IGBT failure detection are limited to indirect analysis through current and voltage, and less to real-Time measurement of internal temperature distribution and thermal conduction state. In this paper, a fiber grating sensing system is introduced in the silica-gel layer inside the IGBT. We design and build a fiber grating sensor system for real-Time monitoring of the IGBT internal temperature distribution and the thermal conduction state of the silica-gel, and it is monitored online in the incubator, laboratory and operating conditions. The system has been running in Xiamen Ludao ±320kV flexible DC converter station demonstration project for five months. The results show that the system has strong stability and fast response time, and the data acquisition can be synchronized with IGBT temperature changing. It provides a reliable basis and timely alarming for the fault detection.