International Journal of Applied Electromagnetics and Mechanics - Volume 56, issue 4

Authors: Ohji, Takahisa | Suda, Kazuki | Kusano, Satoshi | Amei, Kenji | Kiyota, Kyohei

Article Type: Research Article

Abstract: In general, the magnetic levitation (maglev) force on a nonmagnetic metal generated by an alternating magnetic field becomes a repulsive force; therefore, the nonmagnetic metal can only be pushed up from below by the repulsive force. In contrast, our prototype device succeeded in continuously pulling up a thin aluminum ring with a diameter of 120 mm by using ac electromagnetic force based on the ac ampere type maglev method we have proposed. This system operates just as if a permanent magnet attracts a magnetic material. This paper describes the configuration of the prototype device, derivation of exciting current conditions for …generating the ac ampere force using finite element analysis and demonstration of steady levitation force and pull-up operation. Show more

Keywords: Magnetic levitation, ac ampere force, pull-up operation, aluminum ring, finite element analysis

DOI: 10.3233/JAE-170134

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 56, no. 4, pp. 637-644, 2018

Authors: Kong, Wangqi | Zhang, Yang | Huang, Mingming | Huang, Quanzhen

Article Type: Research Article

Abstract: Permanent magnet vernier machine (PMVM) based on flux modulation principle has attracted increasing attention in low-speed direct-drive applications due to its high torque capability. A novel flux concentrating multi-tooth splitting poles permanent magnet vernier machine (FCMSP-PMVM) was proposed and designed, which has higher flux density relative to the conventional surface ones. The analytical cogging torque expression of the machine is derived by Maxwell energy method and Fourier series expansion to comprehensively provide insight into the variation of the cogging torque with main parameters. The number of flux modulation pole (FMP) per stator tooth, the circumferential width and radial depth of …each FMP, pole arc coefficient, namely N 𝐹𝑀𝑃 , k d , k p and α p are defined to investigated the relationship between machine unique parameters and its cogging torque. Analysis and computation of the cogging torque characteristic of the proposed flux concentrating PMVM are studied by time-step finite element analysis (FEA). The FEA results demonstrate that N 𝐹𝑀𝑃 , k d and k p are the key parameters to the cogging torque optimization for the proposed machine. It is also confirmed that the pole arc coefficient has small influence to the cogging torque of the proposed machine compared with the traditional PM machines. Finally, a FCMSP-PMVM prototype is built to verify the above analysis and computation. The measured performance of the constructed prototype machine has confirmed the correctness of finite-element modeling results. Experience gained from this study has led to develop a set of design rules for the concentrated winding PMVM. Show more

Keywords: Direct-drive, flux modulation, permanent magnet machine, vernier machine, cogging torque

DOI: 10.3233/JAE-170138

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 56, no. 4, pp. 645-656, 2018