Design and optimization of direct drive 8/6 External-Rotor Switched Reluctance Motor (Ex-R SRM) for low speed application

This paper presents a design and optimization of an 8/6 External-Rotor Switched Reluctance Motor for a low speed domestic application as direct drive. The initial design dimensions are derived from the analytical calculation using magnetic equivalent circuit. This is further analyzed and verified with finite element analysis. A prototype has been developed and tested for Inductance profile to baseline the simulation model accuracy. It is also tested for various on/off conduction angles for an R-dump converter to study the impact on torque ripple. Further, a detailed fractional factorial study has been conducted through Design of Experiments (DOE) to identify the critical dimension which are sensitive to Peak and Average torque. This data is further analyzed through regression analysis and fit a transfer function. This transfer function is helpful in finding optimum design without spending further much time in finite element analysis. Finally, the optimum design is further optimized on conduction angles based on the initial study and arrived at the optimum on/off angles for conduction which gives high average torque and compared with initial design.