Advanced Active Neutral Point Three Level Inverter with Standard Half-Bridge Modules

Abstract:
Three level NPC-inverters suffer from complex commutation circuits [1]. If a 3L-NPC phase is built out of half-bridge modules, the high inductive load terminal of the modules becomes part of the commutation circuit. In this paper, a new control scheme for an active neutral point clamped (ANPC) three-level-inverter is proposed. It allows the realization of one three level phase out of three half-bridge modules, by avoiding high inductive commutations with DC voltage. The remaining commutation paths are either low inductive with DC link voltage or high inductive but without a voltage source. The inverter control with space vector modulation was successfully evaluated on a low voltage, low power test system.