|
|
|
| Unbalance Magnetic Force Suppression in Fractional Slot Concentrated Winding PMSM Based on Phase Regulation of Air-Gap Flux Density Harmonics |
| Yang Gongde1, Chen Zongxiao1, Lin Mingyao2 |
1. School of Electrical Engineering and Automation Fuzhou University Fuzhou 350108 China; 2. School of Electrical Engineering Southeast University Nanjing 210018 China |
|
|
|
Abstract The fractional slot concentrated winding (FSCW) permanent magnet synchronous motor (PMSM) with a slot pole combination satisfying Ns=2pr±1 has a high fundamental coefficient of winding and low end resistance, which has attracted attention in motor design. However, the FSCW PMSM has a significant unbalanced magnetic force (UMF) in its rotor, resulting in motor vibration and noise. Currently, most literature employs multi-objective optimization algorithms and modal analysis to optimize motor “modulators” for suppressing UMF. However, there is a lack of theoretical research on minimizing electromagnetic torque output reduction while achieving UMF suppression. Based on the theory of magnetic field modulation, this paper optimizes the slot pole combination. By adjusting the harmonic phase of the air gap magnetic density, the cancellation effect between the first-order radial electromagnetic force waves is enhanced, while suppressing the motor UMF and maintaining the motor electromagnetic torque output. Firstly, the influence of air gap magnetic permeability on the time coefficient and spatial coefficient of the first-order electromagnetic force wave in PMSM is analyzed, and the main harmonic orders of air gap magnetic density that generate UMF and electromagnetic torque are determined. Secondly, the UMF and electromagnetic torque of the motor are quantitatively decomposed, and the cancellation relationship between first-order electromagnetic waves is analyzed. Then, the structural parameters of the stator slot and auxiliary slot are optimized, the harmonic phase of the air gap magnetic density is adjusted, and the cancellation effect between the first-order electromagnetic waves is enhanced. Finally, simulation analysis and prototype experiments were conducted on an 8-pole 9-slot FSCW PMSM. The results show that the electromagnetic torque generated by the 4th air gap magnetic density harmonic is 2.48 N·m, accounting for 97.2% of the total electromagnetic torque (2.55 N·m). In comparison, other air gap magnetic density harmonics only contribute 2.8% of the electromagnetic torque. The phase cancellation relationship between the first-order radial electromagnetic force waves can be enhanced by adjusting the phase between the main air gap magnetic density harmonics. After optimization, the phase difference between the 8-pole 9-slot FSCW PMSM’s f4&5 and f12&13 is 178°, and the phase difference between f3&4 and f4&5 has significantly increased after optimization, resulting in an increased cancellation effect. At rated state, the electromagnetic torque decreases from 2.55 N·m to 2.5 N·m, representing a 1.9% decrease. The total UMF decreased from 134 N to 118 N, representing a 12% decrease. The error between the measurement and the simulation is small. The UMF change rate measured by the pressure sensor in the UMF measurement experiment is approximately equal to the UMF change rate in the finite element simulation. The following conclusions can be drawn. (1) The main air gap magnetic density harmonic order for generating electromagnetic torque in an 8-pole 9-slot FSCW PMSM is 4th, and the main air gap magnetic density harmonic orders for generating UMF are 3rd, 4th, 5th, 12th, and 13th. To maintain the electromagnetic torque output of the motor, the amplitude of the 4th air gap magnetic resonance wave cannot be weakened. However, to effectively suppress the UMF of the motor, the phase cancellation relationship between the first-order radial electromagnetic force waves can be enhanced by adjusting the main air gap magnetic density harmonic phase. (2) Auxiliary slots with smaller stator slot opening width, moderate area, and uniform distribution should be used in the motor manufacturing process to suppress the UMF of FSCW PMSM with a slot pole combination that satisfies Ns=2pr±1 and maintain electromagnetic torque output.
|
|
Received: 25 October 2024
|
|
|
|
|
|
[1] Zhu Z Q, Azar Z, Ombach G.Influence of additional air gaps between stator segments on cogging torque of permanent-magnet machines having modular stators[J]. IEEE Transactions on Magnetics, 2012, 48(6): 2049-2055. [2] 陈浈斐, 邢宁, 马宏忠, 等. 分数槽永磁电机永磁体谐波涡流损耗建模与分析[J]. 电工技术学报, 2022, 37(14): 3514-3527. Chen Zhenfei, Xing Ning, Ma Hongzhong, et al.Analytical modeling and analysis of magnet harmonic loss in fractional slot permanent-magnet machines[J]. Transactions of China Electrotechnical Society, 2022, 37(14): 3514-3527. [3] 边旭, 纪毅, 梁艳萍. 外转子永磁同步电机径向电磁力分析与抑制[J]. 电机与控制学报, 2022, 26(10): 74-80. Bian Xu, Ji Yi, Liang Yanping.Analysis and suppression of radial electromagnetic force of exter- nal rotor permanent magnet synchronous motor[J]. Electric Machines and Control, 2022, 26(10): 74-80. [4] 许孝卓, 刘俊哲, 肖磊, 等. 基于磁-固耦合振动的永磁同步电机多目标优化设计[J]. 电气工程学报, 2024, 19(4): 149-158. Xu Xiaozhuo, Liu Junzhe, Xiao Lei, et al.Multi- objective optimization design of permanent magnet synchronous motor based on magnetic-structural coupled vibration[J]. Journal of Electrical Engin- eering, 2024, 19(4): 149-158. [5] 莫会成. 分数槽绕组与永磁无刷电动机[J]. 微电机, 2007, 40(11): 39-42, 81. Mo Huicheng.Fractional-slot winding and PM brushless motor[J]. Micromotors Servo Technique, 2007, 40(11): 39-42, 81. [6] Dorrell D G, Popescu M, Ionel D M.Unbalanced magnetic pull due to asymmetry and low-level static rotor eccentricity in fractional-slot brushless permanent- magnet motors with surface-magnet and consequent- pole rotors[J]. IEEE Transactions on Magnetics, 2010, 46(7): 2675-2685. [7] 赵玫, 赵君, 左思承, 等. 横向磁通永磁直线电机电磁振动特性分析[J]. 电工技术学报, 2024, 39(1): 168-181. Zhao Mei, Zhao Jun, Zuo Sicheng, et al.Analysis of electromagnetic vibration characteristics of transverse flux permanent magnet linear motor[J]. Transactions of China Electrotechnical Society, 2024, 39(1): 168-181. [8] Ishak D, Zhu Z Q, Howe D.Permanent-magnet brushless machines with unequal tooth widths and similar slot and pole numbers[J]. IEEE Transactions on Industry Applications, 2005, 41(2): 584-590. [9] Dorrell D G, Popescu M, Cossar C, et al.Unbalanced magnetic pull in fractional-slot brushless PM motors[C]//2008 IEEE Industry Applications Society Annual Meeting, Edmonton, AB, Canada, 2008: 1-8. [10] Zhu Z Q, Ishak D, Howe D, et al.Unbalanced magnetic forces in permanent-magnet brushless machines with diametrically asymmetric phase windings[J]. IEEE Transactions on Industry Appli- cations, 2007, 43(6): 1544-1553. [11] Sun Kai, He Yuling, Qiu Minghao, et al.Rotor unbalanced magnetic pull characteristics properties in synchronous generators due to dynamic air-gap eccentricity faults[C]//2021 IEEE 4th Student Con- ference on Electric Machines and Systems (SCEMS), Huzhou, China, 2021: 1-6. [12] Kim D, Noh M D, Park Y W.Unbalanced magnetic forces due to rotor eccentricity in a toroidally wound BLDC motor[J]. IEEE Transactions on Magnetics, 2016, 52(7): 8203204. [13] Li Y X, Zhu Z Q.Cogging torque and unbalanced magnetic force prediction in PM machines with axial-varying eccentricity by superposition method[J]. IEEE Transactions on Magnetics, 2017, 53(11): 1400404. [14] Wu L J, Zhu Z Q, Chen J T, et al.An analytical model of unbalanced magnetic force in fractional-slot surface- mounted permanent magnet machines[J]. IEEE Transa- ctions on Magnetics, 2010, 46(7): 2686-2700. [15] Zhu Z Q, Mohd Jamil M L, Wu L J. Influence of slot and pole number combinations on unbalanced magnetic force in PM machines with diametrically asymmetric windings[J]. IEEE Transactions on Industry Applications, 2013, 49(1): 19-30. [16] Lan Hua, Zou Jibin, Xu Yongxiang, et al.Investi- gation of unbalanced magnetic force in permanent magnet synchronous machines with asymmetric design[J]. IEEE Transactions on Magnetics, 2018, 54(11): 8203305. [17] 薛东辉. 新能源汽车用不均匀齿(槽)距永磁同步电动机不平衡磁拉力、转矩脉动和电磁振动抑制研究[D]. 济南: 山东大学, 2020. Xue Donghui.Research on unbalanced magnetic pull, torque ripple and electromagnetic vibration suppression of permanent magnet synchronous motor with uneven tooth(slot) pitch for new energy vehicles[D]. Jinan: Shandong University, 2020. [18] 李泽星, 夏加宽, 刘铁法, 等. 基于分段交错不等磁极的表贴式永磁电机极频振动的削弱[J]. 电工技术学报, 2023, 38(4): 945-956. Li Zexing, Xia Jiakuan, Liu Tiefa, et al.Reduction of pole-frequency vibration of surface-mounted per- manent magnet synchronous machines with piecewise stagger unequal poles[J]. Transactions of China Electrotechnical Society, 2023, 38(4): 945-956. [19] 韩雪岩, 王勇, 高俊. 低速永磁同步电机转子偏心的抑制措施[J]. 电机与控制学报, 2023, 27(11): 58-65. Han Xueyan, Wang Yong, Gao Jun.Suppression of rotor eccentricity of low-speed permanent magnet synchronous motor[J]. Electric Machines and Control, 2023, 27(11): 58-65. [20] 潘振芳, 李林. 基于辅助槽的永磁电机不平衡磁拉力抑制[J]. 微电机, 2021, 54(5): 9-13. Pan Zhenfang, Li Lin.Unbalanced magnetic force reduction in PM machines by inserting auxiliary slots[J]. Micromotors, 2021, 54(5): 9-13. [21] 李泽星, 夏加宽, 刘铁法, 等. 基于极间虚齿的表贴式永磁电机六倍频振动噪声的削弱[J]. 电工技术学报, 2023, 38(5): 1287-1298. Li Zexing, Xia Jiakuan, Liu Tiefa, et al.Reduction of six times frequency vibration and noise of surface- mounted permanent magnet synchronous machines with interpolar virtual teeth[J]. Transactions of China Electrotechnical Society, 2023, 38(5): 1287-1298. [22] Cheng Ming, Han Peng, Hua Wei.General airgap field modulation theory for electrical machines[J]. IEEE Transactions on Industrial Electronics, 2017, 64(8): 6063-6074. [23] 程明, 文宏辉, 花为, 等. 电机气隙磁场调制统一理论及其典型应用[J]. 中国电机工程学报, 2021, 41(24): 8261-8283. Cheng Ming, Wen Honghui, Hua Wei, et al.General airgap field modulation theory for electrical machines and its typical applications[J]. Proceedings of the CSEE, 2021, 41(24): 8261-8283. [24] Li Ya, Yang Hui, Lin Heyun, et al.Torque generation mechanism and performance evaluation of a dual- sided PM machine with stator U-shaped magnets[J]. IEEE Transactions on Industry Applications, 2022, 58(1): 250-260. [25] Yang Hui, Zhu Z Q, Lin Heyun, et al.Analysis of consequent-pole flux reversal permanent magnet machine with biased flux modulation theory[J]. IEEE Transactions on Industrial Electronics, 2020, 67(3): 2107-2121. [26] Su Peng, Hua Wei, Wu Zhongze, et al.Analysis of the operation principle for rotor-permanent-magnet flux-switching machines[J]. IEEE Transactions on Industrial Electronics, 2018, 65(2): 1062-1073. [27] Wang Peixin, Hua Wei, Zhang Gan, et al.Principle of flux-switching PM machine by magnetic field modulation theory part II: electromagnetic torque generation[J]. IEEE Transactions on Industrial Electronics, 2022, 69(3): 2437-2446. [28] Zhu Z Q, Liu Yue.Analysis of air-gap field modu- lation and magnetic gearing effect in fractional-slot concentrated-winding permanent-magnet synchronous machines[J]. IEEE Transactions on Industrial Elec- tronics, 2018, 65(5): 3688-3698. [29] 刘栋良, 詹成根, 屈峰, 等. 无人机17 kW电机振动噪声分析与巡航转速下尖端噪声优化[J]. 电工技术学报, 2024, 39(6): 1749-1763. Liu Dongliang, Zhan Chenggen, Qu Feng, et al.Vibration noise analysis and tip noise optimization of unmanned aerial vehicle 17 kW motor at cruise speed[J]. Transactions of China Electrotechnical Society, 2024, 39(6): 1749-1763. [30] 张玉峰, 高文韬, 史乔宁, 等. 基于改进迭代田口法的双余度永磁同步电机优化设计[J]. 电工技术学报, 2023, 38(10): 2637-2647, 2685. Zhang Yufeng, Gao Wentao, Shi Qiaoning, et al.Optimization design of dual-redundancy permanent magnet synchronous motor based on improved iterations taguchi method[J]. Transactions of China Electrotechnical Society, 2023, 38(10): 2637-2647, 2685. [31] 陈少先, 丁树业, 申淑锋, 等. 船舶用表贴式永磁同步电机的电磁振动分析与抑制[J]. 电工技术学报, 2023, 38(5): 1275-1286, 1298. Chen Shaoxian, Ding Shuye, Shen Shufeng, et al.Analysis and suppression of electromagnetic vibration of surface mounted permanent magnet synchronous motor for ships[J]. Transactions of China Electro- technical Society, 2023, 38(5): 1275-1286, 1298. [32] 刘凯, 张炳义, 冯桂宏. 基于电枢齿偏移法双面转子永磁同步电机振动噪声特性的研究[J]. 电工技术学报, 2021, 36(增刊1): 95-106. Liu Kai, Zhang Bingyi, Feng Guihong.Research on electromagnetic vibration and noise characteristics of dual sided rotor permanent magnet synchronous motor based on armature offset approach[J]. Transa- ctions of China Electrotechnical Society, 2021, 36(S1): 95-106. |
|
|
|