A simplified space vector based current controller for any general N-level converter

This paper proposes a simplified current controller for any general N-level converter based on space vector (SV) theory. Through the presented mapping technique between the subhexagon of the N-level converter and the hexagon of the two-level converter, the proper output voltage vector of the N-level converter can be identified to suppress harmonic current content in steady state and attain fast current response in transient state. Meanwhile, the redundant switching states of the voltage vectors can be used to reduce or balance the device power losses, and regulate floating capacitor voltages. The controller complexity is greatly reduced due to the use of very simple lookup tables, thus it can be easily extended to any general N-level converter. The proposed scheme is explained for a five-level active NPC converter and the simulation results are presented to prove its correctness.