An Improved Analytical Model for the Novel Counter-Rotating Axial-flux Hybrid-excitation Permanent Magnet Machine

In order to accurately predict the magnetic field distribution of the counter-rotating axial-flux hybrid-excitation permanent magnet (CR-AFHEPM) machine, an improved subdomain model is proposed in this paper, which combines the Ampere's circuital law with the KCL for equivalent magnetic circuit. Firstly, a simplified subdomain model is established in the Cartesian coordinate system, and the constraint equation considering the excitation circuit is derived by combining the excitation winding and the end of the armature winding. Then, considering the influence of soft magnetic composite (SMC) material saturation, the magnetic vector potential and magnetic density of each subdomain are iteratively calculated, effectively reducing the error of the magnetic field distribution. Finally, accurate prediction is made on the magnetic field distribution and magnetic regulation characteristics of the CR-AFHEPM, and eddy current losses of the permanent magnet are calculated. This model is proven to have significant accuracy in the CR-AFHEPM, providing a novel and convenient method for magnetic field analysis and permanent magnet loss calculation of such machines.