Fault-Tolerant Sensorless Control for Six-Phase PMSM with Dual Back-EMF Observer

The paper deals with the sensorless control strategy used as a sensor backup for safety-critical applications. The sensorless control strategy is realized through a redundant extended Back-EMF observer structure applied to an asymmetrical six-phase permanent magnet synchronous machine (PMSM), controlled by a standard field-oriented control. A simplified vector space decomposition approach has been implemented to eliminate the current unbalance between two sets of three-phase windings. Fault-tolerant sensorless control strategy has been proposed in this paper for the case of open phase fault. Experimental investigation on a 1kW dual three-phase PMSM drive confirms the feasibility and effectiveness of the redundant sensorless control solution.