Mechanical Design and Analysis of a High-Torque Modular Hybrid Excitation Synchronous Machine for Electric Vehicle Propulsion Applications

Abstract

Although hybrid excitation synchronous machines (HESMs) can provide an attractive flux-regulating capability, the fabrication and mechanical strength of the complex rotor are with significant challenges and need great efforts especially for high torque machines. In this article, a modular fabrication method of the dual-end magnetic-shunting rotor is proposed for high torque hybrid excitation synchronous machine. Then, by using numerical methods, the thermal stress of the rotor is calculated and compared with the 3-D FEA methods. To improve the mechanical strength of the rotor, the size of the screw, lug boss and filler is optimized, meanwhile, the rotor loss is optimized and thermal stress is evaluated. The results show that the proposed modular fabrication method demonstrates the improved mechanical strength and material utilization rate compared with the conventional fabrication process. Based on the three-dimensional finite-element analysis (3-D FEA) results, a 100 kW HESM prototype is successfully designed and manufactured using the proposed modular magnetic-shunting rotor. The experimental tests validate the effectiveness of the modular fabrication method and mechanical strength analysis.