Design Method of Variable-Flux Machines for Improving Torque Density

• Published in: 2022 25th International Conference on Electrical Machines and Systems (ICEMS) pp. 1 - 5
• Main Authors: Liu, Faliang, Wang, Mingqiao, Liu, Yong, Zheng, Zaiping, Zheng, Ping, Fu, Jie
• Format: Conference Proceeding
• Language: English
• Published: IEEE 29.11.2022
• Subjects: Air gaps; Design methodology; magnetic circuit; Magnetic flux; Mathematical models; permanent-magnet (PM); Simulation; Synchronous machines; Torque; variable-flux machine
• ISSN: 2642-5513
• DOI: 10.1109/ICEMS56177.2022.9982829

In order to improving the torque density of the variable-flux machine, design methods for both series and parallel configurations are proposed based on the theoretical analysis. After the traditional rare-earth permanent-magnet (PM) synchronous machines (PMSM) is converted into the VFM, two typical configurations of the VFMs are given. To determine what kinds of low-coercive-force (LCF) magnets possessing torque improving capability, the simplified equivalent magnetic circuits for both configurations are established. The torque improving method for the series-configuration VFM is deduced based on the magnetic circuit. The output capability of series-configuration VFM with different LCF magnets are analyzed, which validate the accuracy of the deduced method. Then, by assuming the magnetic reluctance of the teeth and yoke is much smaller than other reluctances, the contour maps of air-gap flux density for the parallel-configuration VFMs are investigated. Based on the proposed methods, the torque density of the VFMs with series-, parallel- and hybrid-configuration can be improved.