The vernier permanent magnet machines (VPMMs) have attracted extensive research interest due to inherent high torque density, which is brought by the “magnetic gearing effect” based on slot-toothed air gap. Regularly, the air-gap topology of VPMM is initially determined and produces the certain composition of magnetic field harmonics, which decides the torque capability. Output torque is improved in a limited way via repeatedly optimizing the air-gap structure parameters. Herein, a quantitative air-gap construction method is proposed to construct the air-gap topology that could produce the magnetic field harmonics of which the total torque generation is maximum. With air-gap permeance as the bridge between torque and magnetic field harmonics, the proposed method quantitatively designs the optimal amplitude of individual radial air-gap permeance unit. Then, the length of the corresponding air-gap unit is obtained, which are assembled to form the final air-gap topology. The proposed method is applied on a surface-mounted VPMM (SVPMM) to illustrate. In theory, the torque density of the proposed machine could achieve 32 Nm/L under natural cooling when electric loading is 250 A/cm. Compared to the open-slot counterpart under the same conditions, the rated torque of the proposed machine is theoretically 68% larger, and is still 32% larger despite the saturation in steel. Finally, a prototype is fabricated, and the test results verify the feasibility of the proposed method.
A Quantitative Air-Gap Construction Method to Maximize Torque of Vernier PM Machines
IEEE Transactions on Transportation Electrification ; 9 , 1 ; 463-473
2023-03-01
5525382 byte
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch