Evaluation of Three Cooling Concepts for an Electric Vehicle Motor – 3D Models

The aim of this paper is to model and analyze the performance of a permanent magnet electric motor for an electric vehicle with different cooling duct designs; wave-cooling duct, spiral cooling duct, and cooling in potted end regions. The comparison between designs are made first by using a 2way coupled electromagnetic model and a computational fluid dynamic (CFD) software for a set of operating points, and then by using lumped parameter models (and boundary conditions from the 2-way coupled model) to calculate the drive system performance over the motor operating region. The first task is described in this paper and the second task in an accompanying paper. It is found that the three cooling system designs give similar efficiencies and average component temperatures with some exceptions depending on the loss distribution but also that the hottest regions have different locations. However, the relatively high flow rate of 10 l/min used in the comparison, results in efficient cooling and low temperature difference between the coolant and the aluminum housing.