Space-Vector-Modulated Method for Boosting and Neutral Voltage Balancing in -Source Three-Level T-Type Inverter

摘要

In this paper, a new modulation method is proposed for a -source three-level T-type inverter . The -source combines the merits of the -source two-level inverter and the advantages of the -source neutral-point-clamped inverter. Although the previous literature has proved that the space vector modulation (SVM) technique for -source produces the desired voltage transfer gain with minimized switching loss, it cannot deal with the neutral-point (NP) potential balance issue. Therefore, an improved SVM method addressing this problem for -source is proposed. The method simplifies the space-vector diagram of a -source into that of a -source two-level inverter. In order to obtain NP potential balance, the pattern of the conventional symmetric SVM is changed by properly adding or subtracting a percentage of the minimum gate-on time. The upper and lower shoot-through states can be inserted into the improved symmetric SVM, thus offering av few adv- ntages, including boosting ability, NP potential balance, and low switching loss. The considerate stable NP voltage and the boosting gain have been experimentally proven by results from a prototype inverter.