Study on Gate Characteristics and Drive Circuit for 300A/1200V Insulated Gate Bipolar Transistors

This paper presents the design and testing of a gate drive circuit for two parallel-connected 300A/1200V insulated gate bipolar transistors (IGBTs), meant for a 200-kVA voltage source converter. The drive circuit is tested under normal as well as fault conditions. The drive circuit performance is shown to be affected by the parasitic inductance in the gate circuitry. A procedure for estimating the equivalent gate inductance based on the measured switching characteristics is presented. The dependence of the Miller plateau voltage in the gate characteristics on the gate resistance and the magnitude of current switched is studied experimentally. The effect of off-state gate voltage on the switching characteristics is also studied experimentally. A procedure to determine the safe minimum negative-bias gate voltage is indicated.