Optimum Design of IE5 Energy-Efficiency Class Synchronous Reluctance Motor

The paper describes the design of the synchronous reluctance motor of the IE5 energy-efficiency class with fractional winding (2.5 slots per pole and phase) for fan applications. The optimization is done with the Nelder-Mead method. The objective function is constructed of the following parameters: the averaged efficiency over the motor modes of the fan profile (the torque is proportional to the speed squared), the converter power, the torque ripple and the voltage total harmonic distortion at sinusoidal current. The motor efficiency is much higher than the IE5 class requirement and remains high in the wide range of powers at the fan load profile. Also, the motor has low torque ripple despite that its rotor and stator have no skewing.