Abstract:

The power electronic components including IGCT are connected in parallel at both ends of the conventional current injection DC circuit breaker,and the components are used to realize the tasks of breaking the rated current,shunting the short-circuit current and freewheeling in the commutation process,which can reduce the breaking pressure of the fast vacuum circuit breaker.Aiming at the reverse current condition of the IGCT during the short-circuit current breaking process,the influence of the stray inductance of the freewheeling branch of the auti parallel diode assembly on IGCT reverse current is analyzed.On this basis,an improved scheme to reduce the stray inductance of the auti-parallel diode freewheeling branch is proposed.Through simulation and experiment,it is verified that the improved scheme can effectively eliminate the reverse current phenomenon of IGCT,which can improve the reliability of IGCT application and the feasibility of practical engineering application.

Key words: current injection type DC circuit breaker, IGCT, reverse current, auti parallel diode, stray inductance