Modellistica e Progettazione di motori sincroni a riluttanza ad alta velocità per veicoli elettrici.

In recent years, the market of electric cars has been significantly growing compared to the previous period and this trend seems to be confirmed for the coming years, considering the policies adopted by several countries, the car manufacturers’ new strategies, and the improvement of battery and power electronics technologies. Nowadays, most of the Electric Machines (EM) used in the mobility sector are based on Rare Earth (RE) Permanent Magnets (PMs). The high and volatile cost of raw materials for magnets makes their long term availability uncertain, especially since the electric vehicle technology is going to be manufactured in mass production. Therefore, there is a growing attention in alternative solutions that include RE free machines or reduced RE PM machines. In this thesis, one of the most cost effective solutions has been investigated: in particular, the Synchronous Reluctance Motor (SynRel) has been studied in depth. Considering the torque capability of this type of machine, it can be stated that it depends only on the motor anisotropy due to the absence of permanent magnets, which cannot contribute to the torque production. Besides, the SynRel can have good performance, especially if it is compared to the Induction Motor (IM) one. The Synchronous Reluctance Motor is an unusual solution for traction applications since it is characterized by a lower specific torque, a lower power density, and a lower power factor than the one of Permanent Magnet solutions. This thesis aims to maximize the performance of this type of machine by proposing an innovative design procedure that can be applied to High Speed Synchronous Reluctance Motors that have to be adopted in the e mobility in order sector. Different design procedures and technological solutions will be presented, analyzed, and discussed: in fact, robust designs, topology optimization, asymmetric rotors, and adhesive epoxy resin are the main topics that will be treated. The proposed procedures have been applied for the design of the Synchronous Reluctance motors of the H2020 European Project ReFreeDrive that aims to reduce the use of rare-earth materials in the next generation of electric drivetrains, facilitating the industrial feasibility for mass production at low manufacturing costs. Two motor sizes have been optimized and, particularly, they are of 200 kW and 75 kW: their designs have the same stator and rotor shapes for scalability reasons and, hence, to give some benefits to electric vehicle manufacturers. The prototypes have been realized and preliminarily tested for the verification of their mechanical integrity at high speeds, for the bearing running in, and for the tuning of the control parameters. After that, the motors have been fully tested over their torque-speed range to verify their performance and to compare the experimental results with the simulation ones.