Comparison of IGBT Junction Temperature Determination using an On-chip Sensor and the VCE(T) Method
Authors & Affiliations
Narender Lakshmanan1, James Abuogo2, Jörg Franke2, Josef Lutz2 and Thomas Basler2
1) Mitsubishi Electric Europe B.V.
2) Chemnitz University of Technology
This paper investigates the factors responsible for the differences in the IGBT virtual junction temperature Tvj,max determined using the established VCE(T) method and the temperature recorded using an on-chip temperature sensor (Tj sensor) mounted in the centre area of the IGBT chip. The impact of each of the influential factors are quantified using experimental and analytical methods. Increase in power loss density was found to cause an increase in the difference between the two temperatures at a rate of 2 Kelvin per W/mm² as per measurement results. The selection of the measurement delay was found to additionally contribute to the deviation between the estimated Tvj,max by the two methods in the range of a few Kelvin. Furthermore, increase in thermal resistance contributes to an increase in the deviation. By adding several influential factors, an impact of up to 50% difference in power cycling lifetime estimation is possible depending upon the operating conditions.
IGBT Junction Temperature, Tj sensor, Power Cycling, On-Chip temperature sensor.
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