Improved rotor structures for increasing flux per pole of permanent magnet synchronous motor

• Published in: IET electric power applications Vol. 12; no. 3; pp. 415 - 422
• Main Authors: Kim, Hae-Joong, Moon, Jae-Won
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 01.03.2018
• Subjects: 2D‐FEA; EMC; equivalent magnetic circuit; finite element analysis; four‐pole six‐slot structure; fundamental air‐gap flux densities; grade fan motors; improved rotor structures; improved rotor‐type motor; interior PM motor; iron loss; no‐load fundamental air‐gap flux density; no‐load phase back EMF; permanent magnet motors; permanent magnet synchronous motor; PM synchronous motor; power 80 W; Research Article; rotor diameter; rotors; spoke‐type motor; surface‐mounted PM motor; synchronous motors; torque ripple; no-load fundamental air-gap flux density; PM synchronous motor; 2D-FEA; rotors; grade fan motors; finite-element analysis; rotor diameter; improved rotor-type motor; finite element analysis; synchronous motors; improved rotor structures; iron loss; fundamental air-gap flux densities; surface-mounted PM motor; no-load phase back EMF; spoke-type motor; four-pole six-slot structure; interior PM motor; torque ripple; permanent magnet synchronous motor; equivalent magnetic circuit; EMC; permanent magnet motors; power 80 W
• ISSN: 1751-8660; 1751-8679; 1751-8679
• DOI: 10.1049/iet-epa.2017.0432

This study proposes an improved rotor structure that can increase the flux per pole of a permanent magnet synchronous motor. The air-gap flux density of the improved rotor-type motor is calculated using an equivalent magnetic circuit and compared with the calculation result that is obtained using finite element analysis (FEA). In addition, the no-load fundamental air-gap flux density of the surface-mounted permanent magnet motor, interior permanent magnet motor, spoke-type motor, and improved rotor-type motor are compared using FEA. Changes in the no-load fundamental air-gap flux density according to changes in the rotor diameter and permanent magnet usage are examined for each rotor type. A comparison of the fundamental air-gap flux densities of the five rotor types, including the improved rotor-type conducted using FEA demonstrated that the air-gap flux density of the improved rotor-type was highest. A comparison of the no-load phase back EMF of the five types was conducted after designing them in the four-pole six-slot structure. Each rotor type is applied to 80 W-grade fan motors, and the torque ripple and iron loss are compared. A prototype of the improved rotor-type motor is developed, and the no-load phase back EMF and load test result are verified through experiments.