Electromagnetic and Thermal Evaluation of Surface-Mounted PM Vernier Machines

This study investigates the electromagnetic and thermal performance of surface-mounted permanent magnet vernier machines. In particular, different losses and thermal behaviour of PM vernier machines are evaluated considering different gear ratios and the obtained results are compared with a baseline conventional PM machine. In order to have a fair evaluation of the studied machines, the stator and rotor dimensions, as well as current density in the slots, are kept constant, while the stator winding poles and the PM poles mounted on the rotor are varied. The performances of all the machines are evaluated using 2D finite element analyses. Back-EMF, output torque, torque ripple, losses and efficiency are evaluated for the studied machines together with their weight / volume comparison. Finally, thermal analyses are carried out and the impact of temperature on the machines is investigated.