Design of IPM Synchronous Machines Using Fast-FEA Corrected Design Equations

This paper proposes a procedure for the fast preliminary design of Internal Permanent Magnet machines for traction application. Given the stack diameter and electric loading, the method permits to quickly determine the rotor diameter, stator slots and rotor cavities dimensions, and the stack length using FEA-corrected design equations, without time-consuming optimization. The core of the proposed method is the torque and power factor design plane function of the (x, b) coordinates, the former being the rotor to stator diameter ratio and the latter the p.u. iron size. The torque and power factor equations versus (x, b) are formulated using the magnetic equivalent circuit of the machine and then refined via a few selected FEA simulations. A comprehensive design procedure is built, using the Tesla Model 3 motor ratings as reference with a focus on key design inputs as the current and voltage limits and the feasible numbers of turns.