A measurement method to extract the transient junction temperature profile of power semiconductors at surge conditions

This paper presents an experimental measurement method to obtain the transient junction temperature profile of power semiconductor devices in surge current operations. Even though a few methods to estimate the device junction temperature have been reported, they are not focused on dynamic surge conditions or experimental measurements which are important for power conversion and protection equipment such as UPS, motor drives and solid state breakers. A procedure is proposed in this work to extract how the junction temperature grows in a transient surge operation with experimental proof. The procedure is based on the measurement of temperature sensitive parameter such as on-resistance of the semiconductors, and the iteration of the basic measurements to reconstruct the transient junction temperature curve. The application of the proposed method includes the calibration and verification of the thermal simulation, design and optimization, estimation of the device's surge capability, device packaging optimization for thermal design, etc.