Author_Institution :
Dept. of Electr. Eng., Harbin Inst. of Technol., Harbin, China
Abstract :
In this paper, a new magnetic-field-modulated brushless double-rotor machine (MFM-BDRM) is proposed, solving the contradictory problem of the electromagnetic performance and the mechanical strength of an MFM rotor in the traditional MFM-BDRMs. The operating principle of the proposed MFM-BDRM, including the speed and torque relations of the stator, the MFM rotor, and the permanent magnet (PM) rotor, is investigated by an analytical method. The magnetic field distribution law in the air gap, the back electromotive force, and the torque performance of the proposed MFM-BDRM are investigated. To obtain the maximum torque density, the influence of some key parameters, such as PM pole-arc coefficient, span ratio, and thickness of magnetic units, on the maximum torque is investigated. Besides, due to the rich magnetic-field harmonics with high rotating speed in the air gap, the distribution law of iron loss in the proposed MFM-BDRM is investigated. The PM-split method along the circumferential direction is employed to reduce the PM loss. Finally, the overall performance of this new MFM-BDRM is evaluated, including loss, efficiency, power density, and so on.
Keywords :
brushless machines; harmonics; magnetic fields; permanent magnet machines; brushless double rotor machine; electromagnetic performance; magnetic field distribution; magnetic field harmonics; magnetic field modulated double rotor machine; permanent magnet rotor; rotating speed; Electromagnetics; Harmonic analysis; Magnetic fields; Rotors; Stator windings; Torque; Brushless double-rotor machine; Brushless double-rotor machine (DRM); PM loss; core loss; electromagnetic performance; hybrid electric vehicle; hybrid electric vehicle (HEV); magnetic-field modulated; magnetic-field modulated (MFM); permanent magnet (PM) loss;
