Field Path Design Assessments of a High-Performance Small-Power Synchronous-Reluctance Motor

With the ever rigorous operational efficiency requirements, effective copper loss reduction is one of the viable approaches for small-power alternative current motors. Among those cost-effective schemes, by eliminating the rotor windings while keeping the same stator structures, the synchronous-reluctance motor (SynRM) offers a potential substitute for those small-power applications that the induction motors are commonly adopted. Since the key factor that affects the SynRM-generated torque will be the difference between its direct-axis and quadrature-axis inductances, by arranging the rotor field paths aligned to the direct axis and by considering the possible cross-coupling magnetic saturations on the rotor ribs and segments, the performance impacts due to field path arrangements on the rotor will be thoroughly evaluated by 3-D finite-element analyses. From the experimental measurements, it is clear that the operational objectives can be achieved, and the adequacy of the proposed design guidance can then be confirmed.