Low-cost miniature single-phase permanent magnet brushless direct current motor

Abstract

A low-cost miniature single-phase permanent magnet brushless direct current motor includes: a permanent magnet rotor which is a cylindrical shape for magnetizing two radial poles; a stator which includes a "U"-shaped stator iron core and a direct current stator winding penetrated by the stator iron core; and a position sensor which is used for detecting a magnetic pole position of the permanent magnet rotor so as to control a power supply of the stator winding. The stator iron core includes a pure "U"-shaped polar body, a magnetic yoke part, a left pole shoe, and a right pole shoe, wherein the left pole shoe and the right pole shoe are form at an upper part of two arms of the "U" shape; a pole face of the left pole shoe is close to a left side of a cylindrical surface of the permanent magnet rotor; a pole face of the right pole shoe is close to a right side of the cylindrical surface of the permanent magnet rotor; and the stator iron core is characterized in that a plane of two pole horns of at least one pole shoe intersects a symmetry axis of the "U" shape. The motor of the invention can start even if the non uniform air gap is not used, and the problems of the reluctance and the torque fluctuation caused by the non uniform air gap can be eliminated.

Description

technical field [0001] The invention relates to a low-cost miniature single-phase permanent-magnet brushless DC motor, in particular to the magnetic circuit structure of the motor. In the International Patent Classification Table, the classification can belong to H02K29 / 03. Background technique [0002] In order to reduce costs, the miniature permanent magnet brushless DC motor can use a "U"-shaped iron core, and the patent application with publication number CN101854105A discloses this design. The problem is that the motor with this structure can only be excited by single-phase windings, and the uniform air gap commonly used by motors cannot be used between the stator and rotor, so that once the magnetic pole axis of the permanent magnet rotor coincides with the axis of the stator excitation field, the stator will have no starting torque when it is energized. . There is a non-uniform air gap such as a stepped air gap between the stator and the rotor of the motor. When the ...

AI Technical Summary

Problems solved by technology

However, while the non-uniform air gap provides the starting torque, it also reduces the running effect, mainly because the reluctance increases in the increasing section of the air gap, and the non-uniform air gap is bound to be accompanied by the fluctuation of the running torque, thus increasing the vibration and noise

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