A new control scheme of five-level active NPC converters for common mode voltage mitigation in medium voltage drives

This paper proposes a new control scheme of five-level active NPC (5L-ANPC) converters for common mode voltage (CMV) mitigation in medium voltage (MV) drives. By properly synchronizing and selecting the voltage vectors of active frond-end rectifier and motor-side inverter, the peak level of CMV at motor terminals can be effectively reduced, which is required for explosion proof (EX) applications. The characteristics of CMV in back-to-back 5L-ANPC converter drive systems are analyzed and presented. The principles and implementation procedures of the proposed CMV mitigation control scheme is discussed in details. Simulation results are provided to prove the concept.