Challenges in Manufacturing and Identification of Rare Earth Free Synchronous Machines

Inhalt:
This work compares a synchronous reluctance machine (SynRM) to a permanent magnet assisted SynRM (PMaSynRM) with identical rotor geometry and additional Al- NiCo magnets. Thus, no rare earth elements are required for both machines. Design validation requires the manufacturing of these machines and identification of their characteristics. However, commissioning and identification present additional challenges. The SynRM’s rotor position sensor cannot be aligned using the induced voltage method because there is no induced voltage when idling due to the lack of rotor excitation. Considering the PMaSynRM, the demagnetization issues of AlNiCo magnets during manufacturing of electric machines are discussed, and a magnetizing approach for a fully assembled electrical machine is presented. The proposed solutions are applied to machine prototypes to compare the characteristics with and without magnets considering flux linkages and torque.