Modified 2-D Model for 3-D Rotor Magnet Leakage Effects in PM Spoke Machines

The aim of this paper is to predict the electromagnetic behavior of a permanent-magnet electric motor with a spoke rotor geometry for motorsport applications. Radial-flux spoke permanent-magnet machines are designed to achieve high torque with reduced volume and weight. However, for this type of machines, three-dimensional (3-D) rotor leakage effects are considerable and need to be assessed at the very early stage of the design process. In this study, analyses have been carried out using a new two-dimensional (2-D) modified model allowing to take into account the 3-D rotor leakage effects. The leakage has been predicted in relation to motor attributes through an easy and accessible formulation that has been validated against 3-D simulations and experimental results. Using the 2-D proposed model, motor performances have been evaluated over the Le Mans driving cycle, without recurring to 3-D models.