Magnetic Bearing Design and Operation to Minimize the Axial Length of High-speed Rotor

In this study, a fork-type heteropolar(FHP) magnetic bearing is proposed as an innovative advancement in magnetic bearing technology. The FHP magnetic bearing enhances winding density within the slot by positioning bobbins, and housing paired windings, side by side. In addition, a comparative analysis was conducted against the conventional heteropolar(CHP) magnetic bearing. The design of the FHP magnetic bearing optimizes the width of the magnetic pole surface by aligning it with the axis direction, enabling maximum force generation. Mathematical modeling and Campbell diagram analysis were employed to quantify the reduction in axial space achieved by the FHP magnetic bearing. Finite element analysis was performed to examine force characteristics and experimental verification confirmed the stability of the FHP magnetic bearing. Additionally, the FHP magnetic bearing was applied to an oil-free refrigerant compressor, validating its practical viability in industrial applications.