Research On High-Power IGCT Converter Fault Analysis And Protection System

Integrated gate commutated thyristor(IGCT)as a typical of the third-generation power electronic devices,with high current,high voltage,high reliability,low loss,compact structure and other characteristics,has been widely used in high voltage power converters.Based on the integrated gate commutated thyristor(IGCT)NPC converter,the paper analyzes the characteristics of IGCT device applications,device failure and converter fault,straight fault detection and protection.The IGCT feature which is taken as an example in this paper has set up simulation model in PSIM.Combined with IGCT single tube test circuit,it analyzes the IGCT switching waveforms generated for IGCT which lays the foundation for IGCT straight fault detection and protection strategy.This paper studies the characteristics of IGCT device applications.As the same time,combined with theoretical commutation conditions,it presents the theoretical of three-level IGCT converter dead time and minimum pulse width settings.According to the three-level NPC converter commutation process theory,it studys the importance of re-trigger for device security application and the necessity of setting re-trigger in all kinds of working status.It is given re-trigger driving pulse waveform in PSIM simulation environment.This paper analyzes the causes of the failure of IGCT devices,including IGCT overvoltage,di/dt exceeding the range and unique commutation failure.At the same time based on three-level IGCT converter working principle,it analyzes converter fault pass-through path both in failure of control system IGCT switch.On this basis,it analyzes the impact of the one-phase inverter bridge arm straight failure.Against the diffcuity of straight fault detection and protection,using the measured data and simulation in PSIM,it proposes three kinds of pass-through fast fault detection method.Based on surge characteristics of IGCT devices,it proposes protection methods of turning on bridge arm and CROWBAR.