Nonlinear Analytical Solution in Axial Flux Permanent Magnet Machines using Scalar Potential
Liu Ye1, Guo Baocheng1, Chen Yequn1, Xiao Sicong1, Zhao Zhen2
1. NARI School of Electrical and Automation Engineering Nanjing Normal University Nanjing 210023 China;
2. Jiangsu CRRC Electric Co. Ltd Dafeng 224100 China
Analytical model (AM) has significant value in the early design stage for electrical machines, in terms of both time and accuracy. AM can be developed based on vector or scalar potential. Until now, almost AMs for armature reaction are using the vector potential. However, scalar potential has advantages of simple description and fast calculation, but it is difficult to model armature reaction by scalar potential since the armature reaction magnetic field has a curl effect. To solve this problem, the axial flux permanent magnet motor is taken as the research object in this paper, and the armature reaction and the nonlinear characteristics of the core are focused on, hence, an accurate two-dimensional analytical calculation method based on scalar magnetic potential is proposed.
The fundamental harmonic analytical model with scalar magnetic potential is applied in the rectangular coordinate system. In order to consider the distribution characteristics of the armature conductor, the armature winding is equivalent to a thin current sheet stacked on the boundary, the stator is considered as a slot without a tooth tip to simplify the calculation. Consequently, there are three calculation regions in the analytical model, namely permanent magnet, air gap and stator slot. Then, the model can be developed and solved by using harmonic sub-domain technique. In order to consider saturation, an iterative process is developed in the proposed model. Moreover, quasi-3D methods, which are widely used to convert 3D models into 2D models to reduce the computational time, is used to model of 10-slot 4-pole 5-phase concentrated winding amorphous alloy axial flux permanent magnet motor by using finite element software. The cylindrical section at average radius is convert to two-dimensional computational planes. The calculation results, such as the flux densities in the airgap, the stator iron, are compared with the results obtained by proposed model.
The comparison between the results predicted by the AM and the results obtained by the finite element model shows that the proposed AM can effectively predict the air gap flux density distribution of the permanent magnet with different magnetization angles, the armature magnetic field and the load magnetic field. The magnetic density distribution in the stator core also has good calculation accuracy, and the nonlinear characteristics of the core are considered. And it can predict the back electromotive force with high precision. The related experiments are carried out. The results of cogging torque and back electromotive force are in good agreement. The relative error of static torque is 0.6 %, which in the acceptable range.
The AM model based on the scalar magnetic potential is developed and proposed, the effect of calculating the armature magnetic field is achieved. Furthermore, the nonlinear iterative derivation calculation is carried out to obtain the no-load and load characteristics of the motor. The results show that the calculation time is greatly reduced compared with the finite element calculation. Simulation and experimental results verify the accuracy and effectiveness of the analytical model. The calculation model proposed in this paper is not limited to axial flux permanent magnet motor, it also can be used for radial flux permanent magnet machines after modifications with same principle.
[1] 徐奇伟,孙静,杨云,陶特毅,崔淑梅. 用于混合动力车的复合结构永磁电机电磁优化设计[J]. 电工技术学报,2020,35(S1):126-135.
Xu Qiwei, Sun Jing, Yang Yun, Tao Teyi, et al.Electromagnetic Optimization Design of Compound-Structure Permanent-Magnet Motor for Hybrid Electric Vehicle[J]. Transactions of China Electrotechnical Society, 2020,35(S1):126-135 (in Chinese).
[2] 梁子漪,曲荣海,陈智,任翔,李大伟.双机电端口电机系统综述与发展展望[J], 电工技术学报, 2022, 37(19): 4923-4937.
Liang Ziyi, Qu Ronghai, Chen Zhi, Ren Xiang, Li Dawei.Overview of Dual-Electrical-Port Dual-Mechanical-Port Machine System and Their Development[J]. Transactions of China Electrotechnical Society, 2022, 37(19): 4923-4937 (in Chinese).
[3] 孙玉华,赵文祥,吉敬华等.高转矩性能多相组永磁电机及其关键技术综述[J].电工技术学报,2023,38(06):1403-1420.
Sun Yuhua, Zhao Wenxiang, Ji Jinghua, et al.Overview of Multi-Star Multi-Phase Permanent Magnet Machines with High Torque Performance and Its Key Technologies[J]. Transactions of China Electrotechnical Society, 2023, 38(06):1403-1420 (in Chinese).
[4] 李进,张钢,刘志刚,王勇. 城轨交通用飞轮储能阵列控制策略[J]. 电工技术学报,2021,36(23):4885-4895.
Li Jin, Zhang Gang, Liu Zhigang, Wang Yong.Control Strategy of Flywheel Energy Storage Array for Urban Rail Transit[J]. Transactions of China Electrotechnical Society, 2021,36(23):4885-4895(in Chinese).
[5] 戴睿,张岳,王惠军,张凤阁,张何. 基于多物理场近似模型的高速永磁电机多目标优化设计[J]. 电工技术学报,2022,37(21):5414-5423.
Dai Rui, Zhang Yue, Wang Huijun, Zhang Fengge, Zhang He.Multi-Objective Optimization Design of High-Speed Permanent Magnet Machine Based on Multi-Physics Approximate Model[J]. Transactions of China Electrotechnical Society, 2022,37(21):5414-5423 (in Chinese).
[6] 刘云飞, 张炳义, 宗鸣等. 基于非线性混合模型的模块组合式永磁电机磁场解析[J]. 电工技术学报, 2022, 37(18): 4593-4603.
Liu Yunfei, Zhang Bingyi, Zong Ming et al. Analytical Prediction of Magnetic Field in Modular Combined Permanent Magnet Motor by a Nonlinear Hybrid Model[J]. Transactions of China Electrotechnical Society, 2022, 37(18):4593-4603(in Chinese).
[7] LUBIN T, MEZANI S, REZZOUG A.Development of a 2-D Analytical Model for the Electromagnetic Computation of Axial-Field Magnetic Gears[J/OL]. IEEE Transactions on Magnetics, 2013, 49(11): 5507-5521
[8] SPRANGERS R L J, PAULIDES J J H, GYSEN B L J, . Magnetic Saturation in Semi-Analytical Harmonic Modeling for Electric Machine Analysis[J/OL]. IEEE Transactions on Magnetics, 2016, 52(2): 1-10.
[9] DJELLOUL-KHEDDA Z, BOUGHRARA K, DUBAS F.Semi-Analytical Magnetic Field Predicting in Many Structures of Permanent-Magnet Synchronous Machines Considering the Iron Permeability[J/OL]. IEEE Transactions on Magnetics, 2018, 54(7): 1-21.
[10] DJELLOUL-KHEDDA Z, BOUGHRARA K, DUBAS F.Nonlinear Analytical Prediction of Magnetic Field and Electromagnetic Performances in Switched Reluctance Machines[J/OL]. IEEE Transactions on Magnetics, 2017, 53(7): 1-11.
[11] DUBAS F, BOUGHRARA K.New Scientific Contribution on the 2-D Subdomain Technique in Polar Coordinates: Taking into Account of Iron Parts[J/OL]. Mathematical and Computational Applications, 2017, 22(4): 42.
[12] DUBAS F, BOUGHRARA K.New Scientific Contribution on the 2-D Subdomain Technique in Cartesian Coordinates: Taking into Account of Iron Parts[J/OL]. Mathematical and Computational Applications, 2017, 22(1): 17.
[13] WU L, YIN H, WANG D.On-Load Field Prediction in SPM Machines by a Subdomain and Magnetic Circuit Hybrid Model[J/OL]. IEEE Transactions on Industrial Electronics, 2020, 67(9): 7190-7201.
[14] DORGET R, LUBIN T, AYAT S.3-D Semi-Analytical Model of a Superconducting Axial Flux Modulation Machine[J/OL]. IEEE Transactions on Magnetics, 2021, 57(11): 1-15.
[15] DJELLOUL-KHEDDA Z, BOUGHRARA K, DUBAS F,. Analytical Prediction of Iron-Core Losses in Flux-Modulated Permanent-Magnet Synchronous Machines[J/OL]. IEEE Transactions on Magnetics, 2019, 55(1): 1-12.
[16] LUBIN T, MEZANI S, REZZOUG A.Development of a 2-D Analytical Model for the Electromagnetic Computation of Axial-Field Magnetic Gears[J/OL]. IEEE Transactions on Magnetics, 2013, 49(11): 5507-5521.
[17] SPRANGERS R L J, PAULIDES J J H, GYSEN B L J. Magnetic Saturation in Semi-Analytical Harmonic Modeling for Electric Machine Analysis[J/OL]. IEEE Transactions on Magnetics, 2016, 52(2): 1-10.
[18] ERTUGRUL N, HASEGAWA R, SOONG W L.A Novel Tapered Rotating Electrical Machine Topology Utilizing Cut Amorphous Magnetic Material[J/OL]. IEEE Transactions on Magnetics, 2015, 51(7): 1-6.
[19] HEMEIDA A, SERGEANT P.Analytical Modeling of Surface PMSM Using a Combined Solution of Maxwell-s Equations and Magnetic Equivalent Circuit[J/OL]. IEEE Transactions on Magnetics, 2014, 50(12): 1-13.