Design and Analysis of a Magnetic-Field Modulated Brushless Double-Rotor Machine-Part II: Winding Configuration

• Published in: IEEE transactions on industrial electronics (1982) 2019-04, Vol.66 (4), p.2550-2560
• Main Authors: Bai, Jingang, Liu, Jiaqi, Zheng, Ping, Tong, Chengde
• Format: Article
• Language: English
• Subjects: Back electromotive force; Brushless double-rotor machine; Coils (windings); Configurations; design; Electromotive forces; Finite element method; fractional-slot concentrated winding (FSCW); Harmonic analysis; harmonic back electromotive force (EMF); hybrid electric vehicles; integer-slot winding; Magnetic fields; magnetic-field modulated; Permanent magnets; Power capacitors; Power factor; Product design; Rotors; Stator windings; Stators; Torque; Winding; Windings
• ISSN: 0278-0046; 1557-9948
• DOI: 10.1109/TIE.2018.2842736

The analysis of Part I shows that the integer-slot winding of the magnetic-field modulated brushless double-rotor machine (MFM-BDRM) can obtain very sinusoidal no-load and load back electromotive force (EMF) and quite small torque ripple under an optimal pole-pair combination of stator, permanent magnet (PM) rotor, and magnetic blocks. In practical applications, however, the integer-slot winding is usually replaced by the fractional-slot concentrated winding (FSCW), which can reduce end windings and easily realize automatic winding. This paper focuses on the influence of the FSCW on the electromagnetic performance of the MFM-BDRM and the application feasibility of the FSCW in the MFM-BDRM. First, the formation mechanism of the harmonic back EMF of FSCW is investigated. Then the pole-pair combination law of stator, PM rotor, and magnetic block for the FSCW of the MFM-BDRM is further investigated. Second, the specific FSCW of the MFM-BDRM with Q = 2p s ± 1 and Q = 2p s ± 2 and the integer-slot MFM-BDRM are comparatively investigated. It shows that the integer-slot winding of the MFM-BDRM is superior to the FSCW of the MFM-BDRM in no-load and load back EMF, torque ripple, maximum torque outputting capability, and power factor. Finally, the optimal winding configuration of the MFM-BDRM is determined. A prototype of the MFMBDRM with the optimal winding configuration and pole-pair combination is designed and manufactured. The theoretical and finite-element analysis is verified by experiments.