Time-domain and Frequency-domain Analyses of PETT Oscillation in Press Pack IGBTs

Plasma extraction transit time (PETT) oscillation might appear in IGBT devices, which is harmful to the electromagnetic compatibility (EMC) of a renewable energy system. To eliminate this oscillation, its frequency-domain characteristics in wire-bonded IGBT devices have been extensively studied. However, the time-domain analysis of PETT oscillation, especially in Press Pack IGBT (PPI) devices, has not attracted enough attention yet. In this paper, PETT oscillations with multi-chips in PPI devices are systematically investigated by experiments. It is first reported there are multiple resonant oscillations at the tail period when multi-chips turn off. Oscillations overlap in the time domain waveforms, which lead PETT oscillation to be more serious in multi-chips. Then, PETT oscillation is divided into three different feedback states for the first time. For the IGBT chip in the PETT oscillation, its physical based model and behavior model are proposed, which further form the equivalent circuit as the two-port network. Moreover, it is indicated that only parallel resonances can lead to PETT oscillation, which is consistent with experiment results.

Automated summary

This paper systematically investigates the plasma extraction transit time (PETT) oscillations in Press Pack IGBT (PPI) devices with multi-chips. It is first reported that there are multiple resonant oscillations during the turn-off process of multi-chips, and the oscillations overlap in the time domain waveforms, making PETT oscillation more serious in multi-chips. PETT oscillation is divided into three different feedback states for the first time. The physical and behavior models of the IGBT chip in the PETT oscillation are proposed, forming the equivalent circuit as a two-port network. It is indicated that only parallel resonances can lead to PETT oscillation, which is consistent with the experiment results.