A dual-axial flux PMSM with Halbach-array magnetic suspension for compact LVAD systems

Abstract This study investigates the magnetic restoring forces in axial flux permanent magnet synchronous machines (AFPMSMs) under rotor tilting and radial displacement conditions for three magnet configurations: single magnet, 4-segment Halbach array, and 8-segment Halbach array. Finite element analysis (FEA) was employed to characterize the restoring behaviour and assess system stability. The results reveal that while single magnet structures offer greater restoring force at high tilting angles, Halbach arrays provide stronger and more stable restoring forces within limited angles, especially as the number of segments increases. However, this improvement comes at the cost of higher complexity and fabrication effort. For radial displacements, the restoring force also increases significantly with the number of Halbach segments. In a dual-motor configuration, the use of direct current enables active control in the Z -axis, enhancing levitation stability and dynamic response. These findings provide valuable insights into optimal magnet topology and control strategies for AFPMSMs intended for use in magnetically levitated left ventricular assist devices (LVADs), where compactness, precision, and reliability are critical.