Mechanical Analysis and Optimization Considering Electromagnetic Characteristics of High-Speed Rim-Driven Induction Motor for Aviation Ducted Fan

To enhance thrust and efficiency in rim-driven ducted fan, the rim-driven induction motor (RDIM) with the laminated stack rotor has been adopted. However, considering the demand for high speed in aviation electric propulsion, the laminated stack rotor encounters significant challenges associated with stress concentration and breakage. The tip speed of the rotor inner diameter corresponds to the tip speed of the built-in fan, while the tip speed of the rotor outer diameter will be higher. Consequently, the peak Von Mises stress near the outer and inner surfaces of the rotor core becomes considerably high. Against this backdrop, this study analyzes stress distribution characteristics specific to the rim drive topology with different rotor bar shapes. To prevent the laminated stack rotor from experiencing failures, the study proposes an optimized rotor structure and reinforced structure to alleviate the stress concentration. Simultaneously, employing a new stress design in rotor construction may lead to a decline in output performance or an upsurge in losses. To reduce the iteration of stress optimization design and electromagnetic performance analysis, an evaluation methodology for coupling mechanical and electromagnetic characteristics by analyzing the system energy of rotor with different bar shapes is suggested. The stress optimization design was validated through prototype experiments eventually.