Space Vector Modulation Technique for High Power Five-Level PCSI7 with DC Current Balance Control and Common-Mode Voltage Suppression

This paper proposes a new high-power five-level current source inverter topology (PCSI7) and its space vector modulation (SVM) scheme. The topology is composed of two seven-switch current source inverters (CSIs) in a direct parallel configuration. Previously reported paralleled CSI topologies using the conventional six-switch CSI (PCSI6) have restrictions on proper DC current balance control which induces larger harmonic distortions at the inverter's outputs. The PCSI6 topologies also suffer the drawback of relatively high common-mode voltages (CMVs). These disadvantages, however, are significantly alleviated with the proposed PCSI7 and its unique SVM scheme. With the help of the seventh switches, the PCSI7 achieve more frequent DC link current balancing control as well as a reduced CMV. Simulation studies on a 2 MW system verify the superior DC link current balancing and CMV suppression performances of the proposed solution.