MEASUREMENT OF SWITCHING TRANSITIONS IN IGBTS

Abstract

In this project, an experimental set-up was designed and constructed for the purpose of measuring switching losses in IGBTs. As part of the set-up a high frequency current measuring transformer was also designed and constructed and its performance was compared to that of a commercial current measuring probe. From the voltage and current measurements switching losses were determined under different conditions. The switching losses were determined for a range of voltages and it was observed that they varied linearly with the voltage level at a constant value of current. The effect of changing the value of the gate resistance was also studied and it was found that increasing the gate resistance increased the switching losses. The turn-off losses were found to be significantly higher than the turn-on losses because the turn-off transition was done at a higher current level than the turn-on transition. It was also found that increasing the temperature of the IGBT module increased the losses.