Study of the temperature distribution in insulated gate bipolar transistor module under different test conditions

Following improvements in their operating voltage levels, insulated gate bipolar transistors (IGBTs) are largely packaged using parallel packaging processes. However, these processes introduce an uneven temperature distribution problem, regardless of whether pressed or welded packaging is used. In this paper, the temperature inhomogeneity of IGBT modules under various test conditions is studied using a thermography camera. The temperature uniformity is determined for each chip using the difference between its maximum and average temperatures. IGBT module temperature uniformity is evaluated using the difference between the highest temperature and the average temperature of three chips. Experimental results show that when the current level increases, the overall IGBT module temperature also increases. The temperatures of both the module and the chip become increasingly uneven. The temperature of the module shows a Gaussian mode distribution. The positional and discrete parameters of the Gaussian distribution increase with increasing current. As the ambient temperature increases, the temperature inhomogeneity in each IGBT chip increases, but this trend is not dramatic. When the current on-time increases, the temperature distributions of the three IGBT chips and the module gradually become nonuniform.