A Five-/Nine-Level Twelve-Switch Neutral-Point-Clamped Inverter for High-Speed Electric Drives

作者：Ewanchuk Jeffrey^*; Salmon John; Vafakhah Behzad

来源：IEEE Transactions on Industry Applications, 2011, 47(5): 2145-2153.

DOI：10.1109/TIA.2011.2161857

• AC motor drives
• dc/ac power conversion
• multilevel systems
• pulsewidth-modulated inverters

A five-/nine-level twelve-switch inverter is described for three-phase high-speed electric machines having a low per-unit leakage reactance. By reducing the voltage blocking requirement of the semiconductors, the neutral-point-clamped (NPC) variant of the coupled inductor (CI) inverter topology (NPC-CI) is more suited to high dc bus voltages than the six-switch alternative (six-switch CI). Operational and design details are described for the NPC-CI inverter using a three-limb inductor core, including practical considerations for the inverter construction and operation, 480 V/208 V inductor mass comparison between six-and twelve-switch topologies, natural voltage balancing of the split-capacitor dc link, and voltage stresses of the freewheel diodes. Improvements in machine performance are illustrated using two experimental test rigs: an unloaded 18 000-r/min 15-hp induction machine to illustrate improved harmonic quality when operating with a limited switching frequency and a high fundamental output frequency, and a loaded 2-hp utility speed induction machine to demonstrate transient performance.

• 出版日期2011-10