Research on CMV reduction and NPV balance for a T type three level inverter

摘要

An algorithm of common mode voltage (CMV) reduction and neutral point voltage (NPV) balance was proposed for a T type three level photovoltaic grid-connected inverter. Several kinds of common mode voltage reduction methods based on space vector were analyzed. The common mode voltage size and frequency caused by the modulation method were summarized. The impact on the neutral point voltage when synthesize the same reference vector using different modulation method were compared. According to neutral-point voltage deviation degree, a modulation method to inhibit neutral point voltage static offset or dynamic fluctuations was chosen. The simulation results verify the correctness and validity of the proposed algorithm.