Investigation of Switching Behavior of an IGBT under Soft Turn-off in Application for Dual-Active Bridge Converters

To investigate the behavior of insulated gate bipolar transistors (IGBTs) applied in dual-active bridge (DAB) converters, for first approach, the switching behavior of a 3300 V IGBTs with a snubber capacitor in parallel is analyzed using the software TCAD. Simulations confirmed that a long-tail current appears due to low dV/dt of the collector-emitter voltage. This causes increased turnoff losses even under zero voltage soft-switching (ZVS) conditions. To resolve this issue, reduced tail current structures are proposed and analyzed.