Gating and protection of IGBT in an inverter

The authors present the development of a novel gate drive for the insulated gate bipolar transistor (IGBT). Apart from the essential functions of the pulse voltage level control and isolation, the gate drive generates the galvanically isolated status signal, detects overcurrent through the device, and withdraws gate pulse in the event of overcurrent. The status signal generated by the gate drive is used to interlock two IGBTs in a phase of an inverter so that simultaneous conduction of the two IGBTs is avoided. The gate drive detects the overcurrent indirectly by monitoring the collector-emitter voltage. The authors also discuss the results of mathematical analysis of the short-circuit current in a chopper using IGBTs, BJTs, and GTOs (gate turn-off thyristors), with a view to explaining the concept of protection of IGBTs using collector-emitter voltage