Ricerc@Sapienza

Due to the recent growth of the electric and hybrid traction market, the automotive industry is asking electric machines manufacturers to ever increase the power density, in order to have lightweight, more compact and less expensive powertrains. As a result, there is an increasing trend towards designing electrical machines for higher fundamental frequencies (that can reach above 1 kHz) and higher electric and magnetic loadings which result in higher losses. Therefore, whether the need is to increase the power of the machine keeping the same size, or the goal is to reduce the machine's size at the same power, the result is that the surface available to extract losses becomes less and less.
The drive for higher power density, therefore, will produce two main consequences. The first one, the easier to spot, is that research will be directed towards more effective ways to extract heat from electric machines. The second one consists in the fact that - with the machine performances approaching the limits - the electromagnetic design and the thermal design will become tightly interconnected.
The proposed research aims at addressing both the previously described issues with specific applications to Axial Flux Permanent Magnet (AFPM) Synchronous Machines.
Using a water cooled AFPM machine as a baseline and keeping the same active parts, within this project a modified prototype will be built equipped with the proposed direct oil-cooling for end windings system. It is expected that the new cooling system will be more efficient in extracting heat from the machine, allowing a significant increase in power density. The fully modified AFPM machine prototype will be tested experimentally using image-based velocimetry techniques and modeled using CFD analysis.