Study and development of a brushless motor with an eccentric permanent magnet rotor

• Main Authors: You-Han Ke, 柯佑翰
• Other Authors: Shang-Teh Wu
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/yk394h

碩士 === 國立雲林科技大學 === 機械工程系 === 102 === An axial-flux, brushless motor with an eccentric magnet is developed and studied in the thesis. The conventional axial-flux permanent magnet motor is made up with slices of magnet of alternate polarity; the magnetic flux distribution may not be smooth enough. The new motor is constructed with two concentric magnet rings. The eccentric rotation of the magnet rings causes periodic variation of magnetic flux passing through the stator winding. The magnet core is simple to manufactur and the generated back emf has a smooth spatial distribution. Since the magnetic field is symmetric about the axis the magnet rings, simulation can be conducted by a 2D finite-element software. The computed magnetic density is post-processed using Scilab, a freeware. Motor refinement is performed by adjustment of the diameters and thickness of the manet rings, the air gap, the winding dimension and the eccentricity. The final design with two balanced magnet cores and a magnetically conductive casing is examined by a 3D simulation tool. A couple of prototype motors are also manufactured. The measured back emf at constant rotation compares well with simulation results.