Ultra-fast Scaling of Permanent Magnet Machines for Application in Electric Vehicles

An increasing awareness on ecological issues is a strong motivation for more efficient and less petroleum-dependent vehicles. The integrated electrical machines and power electronics is a potential key technology for improvement of vehicle propulsion systems. To have significant effect, electric drive technologies including the applied electrical machine should be optimized to meet the main demanded specifications covering the range of operating points. With such requirements of power, torque, efficiency and weigh, the design and sizing of electrical machines is particularly challenging. In this regard, this paper presents the derivation of ultra-fast scaling laws for permanent magnet synchronous machines (PMSMs) which are widely applied in electric vehicle (EV) applications. They basically consist of three independent scaling procedures: radial scaling, axial scaling and rewinding. The exact analytical equations for the performance parameters of the scaled machine are derived and validated by the motor design software package “Motor CAD Emag” based on finite element analysis (FEA). The potential usage of the scalable equations is to find the optimum size of the scaled machine to meet the requirement of EV traction motor and the driving cycle performance.

Keywords:

scaling laws , permanent magnet synchronous machines , traction motor , series of motors