A Novel Air-Gap Profile of Single-Phase Permanent-Magnet Brushless DC Motor for Starting Torque Improvement and Cogging Torque Reduction

We propose a new air-gap profile for single-phase permanent-magnet brushless dc (SP PM BLDC) motor to improve starting torque and to reduce cogging torque. We calculate starting torque and cogging torque using finite-element (FE) analysis. We perform a parametric analysis to study the effect of variation of proposed profile dimensions on cogging torque and starting torque. More than 70% improvement in starting torque and considerable reduction in magnitude of cogging torque is achieved compared to existing tapered air-gap profiles.