PM arrangement design of PM-assisted synchronous reluctance motors for maximize back-EMF and cogging torque reduction

Abstract

This paper proposes the optimization of an isotropic ferrite magnet magnetization direction and arrangements to enable reduces the cogging torque and maximize back-EMF of PMA-SynRM. Firstly, four different models of general magnet arrangement are selected, and then FEM analysis is carried out with four different magnetization directions for each of four models. Secondly, based on the initial model, optimization design for maximum back-EMF and minimum cogging torque and THD is performed. Thirdly, in order to ensure the safety of the design the PM characteristics such as demagnetizing force, PM energy product, air-gap flux density and stiffness analysis of rotor structure are analyzed by FEM. Finally, validity and superiority of the optimization design are confirmed by manufacturing the prototype motor and performing the experiment.