A modulation technique of neutral point clamped converters with common-mode voltage reduction and neutral-point potential balance

摘要

Common mode voltage output is closely associated with switching states in three-phase three-wire neutral-point clamped inverter. Detailed analysis shows avoiding redundant states can effectively improve the common mode voltage, so this paper proposes a pulse width modulation (PWM) technique with zero redundant states to reduce the common mode voltage output, and evaluate their performance with the conventional PWM scheme. This study also takes the issue of neutral point potential deviation compensation into consideration. Laboratory test results are presented to verify the effectiveness of proposed scheme.