Rotor Design With and Without Permanent Magnets and Performance Evaluation of Synchronous Reluctance Motors

Nowadays, low cost and high efficiency electrical motors are useful in order to reduce the growing energy consumption. Synchronous Reluctance Motors (SynRMs) with and without permanent magnets (PMs) have a somewhat higher efficiency and nevertheless acceptable cost compared to induction machines. This paper focuses on the rotor design without magnets and with PMs and its impact on the performance (torque, power factor and efficiency) of SynRMs. Moreover, the influence of different rotors on the magnetic saturation of the motor is studied. A low cost ferrite PM amount has been added into the optimized rotor of the SynRM to obtain a PM assisted SynRM. A comparison between the motor performance for both reference, optimal and PM rotors has been employed using FEM. It was found that the torque density and the efficiency of the machine increased by about 9.5% and 0.18% respectively when replacing the reference rotor by the optimal one, and by 15% and 0.55% respectively when inserting ferrite PMs in the center of the optimal rotor. In addition, the power factor of the optimal SynRM increased by 17.6% with inserted PMs. The SynRM efficiency and power factor can reach 95.63% and 0.93 respectively. For the reference motor, the simulation results have been validated by measured results