Modelling of hybrid homopolar radial magnetic bearing considering flux leakage

Hybrid homopolar radial magnetic bearings (HHRMBs) combine the benefits of permanent magnet biasing and homopolar magnetic structures, offering high efficiency and low power consumption for high-speed and precision applications. However, the integration of permanent magnets introduces significant modeling challenges, particularly regarding flux leakage effects. This paper proposes a comprehensive modeling and design framework for HHRMBs, incorporating a refined equivalent magnetic circuit model calibrated by two-dimensional finite element method (2D FEM) analysis. The model explicitly accounts for flux leakage paths in both bias and control flux circuits, significantly improving prediction accuracy. A parametric design methodology is developed based on geometric relationships, enabling preliminary structural determination. Furthermore, a multi-objective optimization using the NSGA-II algorithm is implemented to balance electromagnetic force output, copper loss, and stator volume. Key design variables are selected via Latin hypercube sampling, and a feasible Pareto front is generated under practical constraints. The optimized configuration is validated through FEM simulations, demonstrating enhanced performance and model fidelity. The proposed framework offers a practical and extensible toolset for the design and optimization of advanced magnetic bearing systems.