Affiliations: [a] College of Electrical Engineering, Zhejiang University, Hangzhou, China
Correspondence:
[*]
Corresponding author: Qinfen Lu, College of Electrical Engineering, Zhejiang University, Hangzhou, China. E-mail: luqinfen@zju.edu.cn
Abstract: In order to fast calculate the thrust force and normal force of linear induction motor (LIM) for low-speed maglev train under overall conditions including traction and braking, this paper proposes an improved equivalent circuit (EC) method. Firstly, the improved equivalent circuit model is proposed based on the traditional one by adopting a precision correction factor, which can accurately consider the transverse edge effect of cap-shape secondary conducting sheet. Moreover, the permeability of back-iron and magnetic inductance are amended considering the saturation effect. The corresponding calculation procedure is given out. Then, the precise correction factor is investigated based on 2D finite element (FE) model. By comparison with the traditional Russell and Norsworthy correction factor (RNF), the precision correction factor is proved to be more suitable to LIM with wide-range slip frequency. Finally, the thrust force and normal force of LIM with different slip frequency are predicted under braking and traction conditions by improved EC method. The predicted results and the proposed method are validated by 3D FE method and experiment results.
Keywords: Braking condition, equivalent circuit (EC) method, linear induction motor (LIM), low-speed Maglev train, normal force, slip frequency, transverse edge effect
