Influence of static eccentricity on unbalanced magnetic force of external rotor permanent magnet brushless direct current motor used as In‐wheel motor. Issue 4 (12th March 2019)

• Record Type: Journal Article
• Authors: Ma, Conggan; Cui, Hongwei; Zheng, Ping; Zhang, Yuying; Gao, Haibo
• Is Part Of: IET electric power applications. Volume 13:Issue 4(2019)
• Page Start: 538
• Page End: 550
• Publication Date: 2019-03-12
• Subjects: permanent magnet motors -- rotors -- stators -- brushless DC motors -- magnetic forces -- finite element analysis -- machine theory; eccentric direction -- static eccentricity -- unbalanced magnetic force -- in‐wheel motor -- stator -- complex relative magnetic conductivity method -- Maxwell stress tensor method -- electric frequency -- power source frequency -- frequency components -- eccentricity ratio -- wheel rotation frequency -- external rotor permanent magnet brushless direct current motor -- UMF frequency characteristics -- PMBLDCM -- finite element analysis -- SE ratio; Electric power -- Periodicals; Electric power systems -- Periodicals; 621.305
• DOI: 10.1049/iet-epa.2018.5473
• Languages: English
• ISSNs: 1751-8660

Abstract

Abstract : Here, analytical expressions of the unbalanced magnetic force (UMF）of the stator and the rotor under static eccentricity (SE) are deduced by using complex relative magnetic conductivity method and Maxwell stress tensor method. The frequency characteristics of the UMF are obtained. Further the influence of different eccentricity ratio on the UMF is researched. Then, an external rotor permanent magnet brushless direct current motor (PMBLDCM) with 46 poles and 51 slots used as an in‐wheel motor is taken as an example to verify the frequency characteristics by finite element analysis (FEA). The research shows that the frequency characteristics of the UMF of the stator s related to electric frequency. The frequency characteristics of the UMF of the rotor are related to the power source frequency and the rotation frequency of the wheel. It does not introduce new frequency components when the motor SE occurs. As the SE ratio increases, the amplitude of the UMF increases. The UMF without eccentricity exists in all directions with the change of the time. However, as the eccentricity ratio increases, the direction of the UMF is closer to the eccentric direction.