Two Design Procedures for PM Synchronous Machines for Electric Powertrains

This paper presents a design environment for permanent-magnet synchronous motors (PMSMs). Two design examples for electric vehicle (EV) traction are presented: one interior PM machine of the PM-assisted synchronous reluctance type and one concentrated-winding surface-mounted PM motor. The parametric design software used in this paper includes design equations, finite element analysis (FEA), and multiobjective optimization algorithms for the design of PMSMs. This paper presents two possible design methodologies, for the two mentioned test cases. EV application was chosen for its many challenging aspects, involving flux weakening for extended speed range, discontinuous duty cycles, high transient overload requirements, high efficiency over a large area of operation, and so forth. The design examples are compared with selected benchmark designs in terms of operating range in the torque versus speed domain and efficiency maps, all FEA evaluated. Besides magnetics, thermal and structural aspects are included in the study.