Torque Improvement for High Power Density Machines with Shifted Surface-Inserted Permanent Magnets

doi:10.16183/j.cnki.jsjtu.2023.545

Abstract

Abstract:

High power density is critical to high-performance electrical machines in aviation, and the rotor structures of the machines play an essential role. This paper focuses on the permanent magnet (PM)-shifting rotor to enhance the power density and PM utilization ratio of PM synchronous machines. Aimed at the rated operation point with a power of 150 kW and a speed of 12 000 r/min, global optimizations using the non-dominated sorting genetic algorithm II (NSGA-II) are applied individually to the surface-mounted, surface-inserted, and surface-inserted-shifted PM machines. Then, the three optimal machines are comprehensively evaluated and compared. Additionly, a comparative investigation is conducted on the surface-inserted-shifted PM machines with different structures and different PM shifting angles. The results reveal that surface-inserted-shifted PM machines achieve a 2.1% increase in power density, a 17.6% reduction in PM usage, and an 11.6% decrease in torque ripple compared to conventional surface-mounted PM machines, indicating strong potential for aircraft applications.

Key words: high power density machine, permanent magnet (PM) synchronous machine, permanent magnet-shifting, NSGA-II optimization algorithm

CLC Number:

TM341

LI Dalin, HUA Hao, LI Ran, XU Shaolun, QI Wenjuan. Torque Improvement for High Power Density Machines with Shifted Surface-Inserted Permanent Magnets[J]. Journal of Shanghai Jiao Tong University, 2025, 59(9): 1237-1248.

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拓扑结构	优化目标	优化变量I	优化变量II	初始种群数	遗传代数	变量交叉概率/%	变量突变概率/%
SPM	最小有效材料质量、最高电磁效率	定子轭厚、定子齿宽、定子槽开口、定子裂比、磁钢极弧系数、转子轭厚		50^[24]	9	98	1
SIPM	最小有效材料质量、最高电磁效率	定子轭厚、定子齿宽、定子槽开口、定子裂比、磁钢极弧系数、转子轭厚	β	58	9	98	1
SIPM-shifting	最小有效材料质量、最高电磁效率	定子轭厚、定子齿宽、定子槽开口、定子裂比、磁钢极弧系数、转子轭厚	β,θ_s	66	9	98	1

拓扑结构	定子轭厚/mm	定子齿宽/mm	定子槽开口/mm	裂比	永磁体极弧系数	转子轭厚/mm	β/(°)	θ_s/(°)
SPM	7.3	5.6	2.6	0.743	0.89	4.6	0	0
SIPM	6.3	4.8	1.2	0.741	0.87	5.6	30.7	0
SIPM-shifting	6	5.4	2.5	0.732	0.89	4.4	21	3.16

拓扑结构	永磁体用量/kg	平均转矩/(N·m)	磁钢利用率/(N·m·kg^-1)	转矩脉动/%
原始结构	1.36	120	88.0	8.40
填充磁钢	1.54	124	80.3	3.94
填充硅钢	1.36	117	86.2	16.00

拓扑结构	定子叠长/ mm	半匝线圈长/ mm	铜耗/ W	铁耗/ W	转子涡流耗/W	反电势基波/V	反电势 THD/%	铜质量/ kg	铁质量/ kg	永磁体质量/kg	有效材料总质量/kg	功率密度/ (kW· kg^-1)	转矩密度/ (N·m· kg^-1)	额定转矩脉动/%	磁钢利用率/ (N·m· kg^-1)
SPM	58.6	111.4	1 801	1 496	238	505	23.30	2.76	4.47	1.65	8.93	16.8	13.37	11.20	72.3
SIPM	55.4	108.5	2 050	1 256	234	443	20.30	3.15	4.27	1.51	8.96	16.74	13.32	11.80	79.0
SIPM-shifting	55.6	108.4	2 032	1 268	242	438	14.70	3.12	4.23	1.36	8.75	17.14	13.64	9.90	87.8