Magnetic, Thermal and Structural Scaling of Synchronous Machines

A fast and accurate method for scaling the dimensions and the performance of Permanent Magnet Synchronous Machines (PMSMs) is proposed, based on the use of flux linkage maps. Starting from a reference design, the scaled machine is designed to comply new peak torque and power, maximum operating speed, voltage and current specifications in seamless computational time. A new design plane is introduced, permitting the minimization of the stack length of the scaled design. The analysis covers the scaling of losses and the rules for scaling the water-glycol stator cooling jacket, which is a common cooling setup for PMSMs in traction application. The torque versus speed characteristics, the efficiency map and the thermal limit of the scaled design are obtained in seamless computational time without need of dedicated finite-element simulations. The e-motor of the BMW i3 is the reference design and the moto-generator 2 of the 4-th generation Toyota Prius is the target application for showcasing the proposed method.