Parallel Short-Circuits in three-level ANPC converters

Inhalt:
The three-level Active-Neutral-Point-Clamped converter can suffer under novel short-circuit faults, the parallel ones. These scenarios consist of two concurrent circuits; the first one is comparable to typical single short-circuit failures with a lower stray inductance and the shorted module. The second circuit has two IGBTs and/or diodes, a freewheeling diode, the failed semiconductor, and higher parasitic inductance. These two paths interfere and change the well-known trajectories of normal short-circuits. The trends of the new parallel failures are investigated by measurements on a three-level converter equipped with 3.3 kV-IGBTs and diodes.