2014 Volume 134 Issue 10 Pages 853-862
This paper presents a protection circuit for a fault under load (FUL). The protection circuit is characterized by the reverse transfer capacitance characteristic of IGBTs. The reverse transfer capacitance depends on the collector-emitter voltage and has a significant influence on the switching behavior under short-circuit conditions and normal conditions. An FUL is detected by monitoring a gate current because the current flows through the reverse transfer capacitance of IGBTs from the collector terminal to the gate terminal under FUL conditions. A physics-based IGBT model shows high accuracy for both static and dynamic characteristics, making it useful for developing a protection circuit for IGBTs subjected to short-circuit conditions. Simulated results using the physics-based IGBT model and experimental results verify the validity of the proposed protection circuit.