Electromagnetic Performance Analysis of an Axially Active-Radially Passive Magnetically Levitated Motor

Abstract

To address the issues of long axial length, low critical speed, and low power density in traditional magnetically levitated motors, an axially active-radially passive magnetically levitated motor is proposed. This motor integrates a consequent-pole motor, an axial magnetic bearing, and a radial passive magnetic bearing (RPMB). RPMBs do not occupy additional axial space and feature a compact structure with a short axial length. Meanwhile, the axial control flux generated by the excitation of axial coils does not pass through the motor stator, enabling natural decoupling between the axial suspension force and the torque. First, its structure and suspension principles are analyzed. Second, finite element analysis (FEA) is conducted to validate the magnetic field paths, flux distribution, axial suspension performance, and torque output capability. Finally, a coupling analysis is performed on the torque and the axial suspension force. Simulation results show that the proposed motor exhibits excellent regulation and decoupling performance between torque and axial suspension force.