Closed-loop Control of a Three-phase Neutral-point-clamped Inverter Using an Optimized Virtual-vector-based Pulsewidth Modulation
Location: USA
Publication date: 2008-01-15
Published in: IEEE Transactions on Industrial Electronics, May 2008
ref. DOI: 10.1109/TIE.2008.918646

Local members

Joan Rocabert

PhD. Senior Researcher

External members

Busquets-Monge, S. , Ortega, J.D. , Bordonau, J. , Beristain, J.A.



This paper presents a closed-loop control scheme for the three-level three-phase neutral-point-clamped dc-ac converter using the optimized nearest three virtual-space-vector pulsewidth modulation, which is a modulation that produces low output-voltage distortion with a significant reduction of the dc-link capacitance. A new specific loop modifying the modulating waveforms is proposed to rapidly control possible perturbations in the neutral-point voltage balance. An online estimation of the load displacement angle and load linear/nonlinear nature is introduced at no extra cost. The remaining part of the control is analogous to the control for a two-level converter with an appropriate interfacing to the selected modulation. The closed-loop control is designed for the case of a renewable-energy source connected to the ac mains, and its performance is analyzed through simulation and experiments.