Experimental study on the influence of junction temperature on the relationship between IGBT switching energy loss and device current

Accurate determination of power losses in semiconductor devices is important for optimal design and reliable operation of a power converter. The switching loss is an important component of the total device loss in an insulated-gate bipolar transistor (IGBT) in a voltage source inverter. The objective here is to study experimentally the influence of junction temperature on the turn-on switching energy loss E-on and turn-off switching energy loss E-off. More specifically E-on and E-off are both related to device current I-c; the influence of junction temperature on the relationship between E-on and I-c and that between E-off and I-c is studied. As the operating environmental conditions and load conditions of power converter vary widely, a wide range of junction temperatures between -35 degrees C and + 125 degrees C is considered here. The experimental data enable precise determination of the switching loss in each device in a high-power converter at any practical operating condition. This leads to precise estimation of total device loss and optimal thermal design of the converter. This further helps off-line and/or on-line estimation of device junction temperatures required for study of thermal cycles and reliability.