International Journal of Applied Electromagnetics and Mechanics - Volume 62, issue 4

Authors: Chang, Jiujian | Fan, Yanen | Zhu, Bo | Luo, Liang | Wu, Jinglai | Pan, Yishan | Kang, Peng

Article Type: Research Article

Abstract: This paper takes the demand of high power density motor for new energy vehicles as the application background. In order to solve the problem of low power density of radial flux motor, a novel direct cooling yokeless and segmented armature axial flux machine (YASA) is proposed. The thermal-fluid multi-physical coupling field of YASA motor has been studied by combining numerical analysis and computational fluid dynamics (CFD). On this basis, the internal relationship among the output power, flow resistance and structural parameters of the cooling system has been studied, and then the parameters of cooling system has been multi-objectives optimized. On …the premise of meeting the pressure loss of the cooling system, the heat transfer efficiency has been improved, and then the output power of the motor has been increased. Show more

Keywords: YASA, cooling system, power density, CFD, pressure loss

DOI: 10.3233/JAE-190085

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 62, no. 4, pp. 823-834, 2020

Authors: Li, Peng | Jiang, Jiafu | Liu, Sheng | Fu, Peng | Huang, Yiyun | Hui, Xie | Qiang, Liu | Hongyan, Zuo

Article Type: Research Article

Abstract: As an important electrical power distribution system of ITER (International Thermonuclear Experimental Reactor) device, PPEN (Pulsed Power Electrical Network) feeds the pulsed loads for the superconducting coils and the heating and current driving systems. The PPEN transforms 400 kV power grid to 66 kV and 22 kV distribution voltage levels by 3 main step-down transformers. In this paper, the power loss of PPEN transformer is analyzed and calculated. The 2D PPEN transformer model is built. The temperature rise of PPEN transformer is calculated by ANSYS software. To validate the feasibility and correctness of the proposed method, the temperature rise test of PPEN transformer …is carried out, then the related results are compared with the test data. Show more

Keywords: ITER, PPEN, temperature rise, ANSYS, short-circuit method

DOI: 10.3233/JAE-190105

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 62, no. 4, pp. 835-844, 2020

Authors: Zhang, Jin | Zhang, Qiuju

Article Type: Research Article

Abstract: The purpose of this paper is to optimize the PM arc ratio of consequent pole permanent magnet vernier machine (CP_PMVM). The operation principle of the CP_PMVM is discussed. An optimization parameter K 𝛼 related to the PM arc ratio is derived. For the CP_PMVM, the amplitudes of the 4th and 14th order harmonics of the air-gap flux density, the amplitude of the back electromotive force (back-EMF) and the average torque all have positive correlations with K 𝛼 . The optimal PM arc ratio is 0.64. The three phase inductances are approximately constants, and the d -axis inductance is equal …to the q -axis inductance. The PM flux linkages are sinusoidal. The no-load back-EMF waveform of the measured phase is nearly sinusoidal. The gear ratio of the CP_PMVM evaluated from the back-EMF is close to the design value. Furthermore, a controller according to the mathematical model is designed. The CP_PMVM vector control with a sliding-mode (SM) speed controller exhibits a smooth starting, and has an anti-jamming capability. Show more

Keywords: Consequent pole (CP) rotor, permanent magnet vernier machines (PMVM), sliding mode (SM), vector control

DOI: 10.3233/JAE-190061

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 62, no. 4, pp. 845-860, 2020

Authors: Zhang, Yunfeng | Gu, Jialiang | Zhang, Erchun

Article Type: Research Article

Abstract: Studying underground propagation effects of lightning electromagnetic fields in different geological environments will contribute to more reasonable designs for protecting underground cables and electronic equipment. In this paper, we have analyzed influences of different geological environments, depths and soil water content on underground propagation of lightning electromagnetic fields in detail by using the finite difference time domain (FDTD) method in the 2-D cylindrical coordinate system to calculate components of underground electromagnetic fields at a horizontal distance of 200 m, including vertical electric field E z , horizontal electric field E r and azimuthal magnetic field H 𝜑 …. The results show that the underground electric field is predominantly horizontal. Propagation of lightning electromagnetic fields in wet clay and wet limestone environment changes significantly compared to freshwater environment. Attenuation is larger with depth in wet clay and wet limestone, while propagation is unaffected in freshwater. When water content in soils ranges from 5% to 25%, the vertical electric field has the largest attenuation and the azimuthal magnetic field has the least attenuation. The electromagnetic fields in clay are most sensitive to changes in water content. Show more

Keywords: FDTD, lightning electromagnetic fields, different geological environments, water content, underground propagation

DOI: 10.3233/JAE-190112

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 62, no. 4, pp. 861-873, 2020