Emerging hybrid reluctance motor drives for electric propulsion

Traditional rare-earth PM synchronous motors have been widely adopted for electric vehicle propulsion due to high torque density and high efficiency. However, rare-earth material is a nonrenewable source. To reduce rare-earth material in electric motors while maintaining vehicle driving performance becomes a challenge. Reluctance motors are potential solutions. This tutorial will first give a review for the emerging reluctance motor drives, including switched reluctance motors, doubly-fed doubly salient motors, variable flux reluctance motors, etc. The technology status for the existing solutions will be comparatively studied. Further, a new family of flux-modulated reluctance motors will be introduced. The proposed designs incorporate flux modulation principle into reluctance motors to improve torque density and efficiency. The proposed motor topologies, operation principles, electromagnetic analysis, and advanced control methods will be comprehensively presented in this tutorial. Finally, some prospects will be given for future development of reluctance motor drives.