Design and optimization of axial flux Brushless DC motors with flexible PCB windings

Nowadays, in the fractional horse power range, the slotless brushless DC motor is already considered as one of the most efficient. However, a significant improvement can still be made by printing the windings on PCBs, allowing the design of more complex shapes with higher fill factors. This master's thesis investigates the optimization of axial flux permanent magnet motors when using the Flex Coil technology. A FEM model is thus proposed for the electro-magnetic coupling, as well as a lumped parameters thermal solution to evaluate the performances of such motors. Then, two hundred machines were optimized machines according to their motor constant. This work, based on the observed results, proposes some correlations to quickly estimate the best performances that could be achieved in a given volume. A comparison between the axial flux motor and its radial counterpart shows that the axial topology performs better when the ratio thickness-radius is less than 40%. Other evaluations show that the use of the Flex Coil technology can improve the performances up to 100%, compared to the commercial solutions currently on the market. This is a real breakthrough. In addition, a prototype has been designed and built in order to validate the simulations.Master [120] : ingénieur civil électromécanicien, Université catholique de Louvain, 201