Tilting Torque Calculation of a Novel Tiered Type Permanent Magnet Spherical Motor

• Published in: IEEE transactions on industrial electronics (1982) Vol. 67; no. 1; pp. 421 - 431
• Main Authors: Gan, Lei, Pei, Yulong, Chai, Feng
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-01-2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Air gaps; Finite element method; Finite-element analysis (FEA); Force; Induction motors; Magnetic fields; Magnetism; magnetomotive force (MMF) distribution; Mathematical analysis; multi-degree-of-freedom (multi-DOF); permanent magnet (PM); Permanent magnet motors; Permanent magnets; pole–slot combination; Product design; Rotors; spherical motor; Stators; Three dimensional analysis; Torque
• ISSN: 0278-0046; 1557-9948
• DOI: 10.1109/TIE.2019.2896290

This paper proposes a novel tiered type permanent magnet spherical motor (T-PMSPM) of which the output torque is relatively higher than that of the most existing spherical motors. The proposed T-PMSPM has three stators along axial direction; each of the stator is consisted of an iron core and a three-phase winding. An analytical method is developed in order to calculate the tilting torque based on the air gap magnetic field distribution generated with the specific pole-slot combinations. For performance verification and accurate calculation, three-dimensional finite-element analysis (FEA) is adopted. Two typical rotor configurations are compared and analyzed, focusing on the ability of large torque production, especially for the tilting torque. Finally, a prototype motor as well as the auxiliary apparatus used for experimental measurements has been manufactured. Considering that the friction torque is nonnegligible, a test procedure of torque measurement and separation is designed and performed. The tilting torque obtained from the experiments is compared with the FEA results after friction compensation.