Effects of Abnormal Gate-drive Waveforms on the Dynamic Switching Characteristics of IGBTs
Yifan Wang, Mingquan Zeng, Zhengyuan Ding, Dun Qian, Ting XuObjective:
This study aims to clarify how abnormal gate-drive waveforms affect the dynamic switching behavior of IGBTs and to identify the underlying physical mechanisms.
Methods:
A physical model of a 3.3 kV trench-gate punch-through IGBT is established, and its static characteristics are calculated. The model is validated against the static characteristics of the corresponding commercial device. A double-pulse simulation circuit is then constructed from the device model to evaluate the dynamic switching characteristics of the IGBT.
Results:
The pre-switching gate-drive amplitude mainly affects switching delay, whereas the postcommand gate-drive amplitude affects both switching delay and transition times. Increasing VG,on reduces turn-on loss, while turn-off loss is comparatively insensitive to VG,off.
discussion:
The carrier-distribution results and simplified gate charge-discharge model indicate that abnormal gate-drive waveforms affect IGBT switching by modifying the gate-voltage evolution, internal charge distribution, and carrier state. These effects are inherited by subsequent switching stages. During turn-off, the tail-current stage is mainly governed by carrier extraction and recombination, making the turn-off loss relatively insensitive to the gate-drive level.
Conclusion:
The effects of abnormal gate drive are mainly governed by gate-charge dynamics and the evolution of internal carrier states.