Analysis of a yokeless electrically excited axial flux machine based on a 2D linear machine modeling approach

The road transport sector is a major contributor to CO₂ emissions, accounting for about 21% of EU emissions in 2022. Electrification of mobility, through hybrid and battery electric vehicles, is a key strategy to reduce environmental impact and reliance on fossil fuels. Among electric traction systems, electric machine design strongly affects efficiency, cost, and sustainability. Permanent Magnet Synchronous Motors (PMSMs) offer high performance but rely on rare-earth materials, while axial-flux machines provide compact, high-torque solutions with better material utilization. Magnet-free alternatives, such as Wound-Field Synchronous Machines (WFSMs), allow active flux control and improved efficiency under partial load. This thesis investigates the Yokeless Electrically Excited Synchronous Machine (YEESMA), which combines a yokeless segmented axial-flux stator with two wound-field rotors and concentrated windings to reduce mass, magnetic losses, and improve thermal management. A two-dimensional Linear Machine Modeling Approach (LMMA) is developed in JMAG, validated against a full 3D model, and used to evaluate AC losses and optimize winding arrangements, providing a framework and practical design guidelines for sustainable, efficient electric traction systems.