Efficiency Comparison of Synchronous Reluctance Machines with Different Rotor Designs

A synchronous reluctance machine (SynRM) contains no permanent magnets; hence, it has reduced cost and is easily assembled/disassembled. A SynRM requires a three-phase inverter, but a switched reluctance motor with no permanent magnets requires special power electronics. Compared with an induction motor, a SynRM has no secondary copper loss induced in the rotor conductors. Based on these advantages, a SynRM is a potential candidate for a generator that operates at a constant speed and rated power. This study compares the efficiency of SynRMs with different rotor designs and circular and quadratic-curve flux barriers. The torque of the model with quadratic-curve barriers calculated by the finite element method was 6% larger than that with circular barriers. The final model had 96.7% efficiency at 2400 rpm with an electrical output of 12 kW.