Two-Phase Commutation Control Method of Open-End Winding PMSM with Reduced Loss for Low Torque Operation

This paper proposes a two-phase commutation control method of open-end winding permanent magnet synchronous machine (OEW-PMSM) with current reference modification. In order to drive OEW-PMSM, dual three-phase inverter is required, and inevitably, the inverter loss becomes significant for low torque operation. At this operating condition reduction, switching phases of the inverter becomes the key for mitigation of the total system loss. In this paper, a mechanism that switching occurs in two half-bridges out of six while the motor conducts the current in two phases is introduced. To maintain the desired output torque with two-phase commutation control, current reference modification is proposed. Based on the analysis, current references to achieve minimum torque ripple and minimum loss are presented. The validity of the proposed control method is verified by the experimental result.