On the Active Clamp Gate Driver Thermal Effects

The IGBT active clamp gate driver is a conveniently method used to protect the switch from the overvoltage by driving the gate input of the IGBT itself. The overvoltage is common during the turn-off of inductive loads or circuits with parasitic elements. This clamping circuit is generally embed into the gate driver circuits. The aim of this paper is to study and model the active clamp circuit giving a compact mathematical model for the power losses calculation. The losses calculation are needed for the heatsink sizing when the system is used in not conventional use, with single or repetitive overvoltages, as for example for the solid state circuit breakers (SSCB) without external passive clamp circuits. Moreover the study has been validated with experimental tests.