Direct Model Predictive Control of three-level NPC back-to-back power converter PMSG wind turbine systems under unbalanced grid

Abstract

Control of grid-tied wind turbine systems under unbalanced grid is one the challenges. This work studies and illustrates several unbalanced grid control methods combined with Direct Model Predictive Control (DMPC) schemes for three level NPC back-to-back power converter Permanent-magnet Synchronous Generator (PMSG) wind turbine systems. Within this paper, three different compensation schemes, i.e., symmetrical current compensation, constant active power compensation, and constant reactive power compensation, using the conventional instantaneous power theory are over-viewed. Then based on a newly reported instantaneous power theory, a DMPC scheme for unbalanced grid three-level NPC back-to-back power converter PMSG wind turbine systems is presented. The performance comparison is illustrated through simulation results.