Fault-Tolerant Control of NPC Three-Level Inverters-Fed Double-Stator-Winding PMSM Drives Based on Vector Space Decomposition

The purpose of this paper is to study and propose the fault-tolerant control schemes for neutral-point-clamped (NPC) three-level inverters-fed permanent magnet synchronous motor drive with double stator windings. Both open-phase faults and open-switch faults are considered. The proposed schemes maintain the advantages of vector space decomposition (VSD) control for multiple-stator-winding drives, where the torque of multiple windings is controlled as a whole. Different optimization goals such as minimum copper loss and minimum current amplitude variance are achieved in the proposed fault-tolerant control for open-phase faults. Moreover, the impacts of open-switch faults on voltage vectors of the drive are analyzed, and the VSD-based remedial schemes are proposed for symmetric operation under open-switch faults by adjusting the switching modulation strategies. The current harmonics and dc-link midpoint voltage deviation are suppressed well with the proposed schemes. Both simulation and experimental results are given to verify the validity of the proposed modulation strategies and control schemes under faulty conditions.