Self-starting permanent magnet motor with three-section-circular-arc magnetic pole structure

Abstract

The invention discloses a self-starting permanent magnet motor with a three-section-circular-arc magnetic pole structure, belonging to the technical field of motors. The permanent magnet motor consists of a stator and a rotor, wherein a permanent magnet in the rotor adopts an embedded structure in which magnetic poles N and magnetic poles S are arranged alternatively; the surface of each magnetic pole of the rotor consists of three sections of circular arcs; the radius of a middle section circular arc of each magnetic pole is the same as that of the outer circle of the rotor, so that a smallest air gap of the permanent magnet motor is ensured; the circle center of the middle section circular arc of each magnetic pole is the same as that of the inner circle of the stator; the radiuses of two lateral circular arcs of each magnetic pole are smaller than the radius of the outer circle of the rotor; and the circle centers of the two lateral circular arcs are closer to the surface of the rotor than the circle center of the middle section circular arc, so that the permanent magnet motor with a non-uniform air gap structure is formed. The angle of the middle circular arc of each magnetic pole and the eccentric distance between the circle centers of the two lateral circular arcs are adjusted, so that the harmonic content of a no-load air gap magnetic field is lower and a reasonable magnetic pole shape is obtained. The influences of the harmonic field and harmonic current of the permanent magnet motor on the motor efficiency and the torque fluctuation are improved remarkably; and the permanent magnet motor is suitable for long-time continuous running working occasions.

Description

Technical field [0001] The invention belongs to the technical field of motors, and particularly relates to a self-starting permanent magnet motor with a three-segment arc structure of the rotor pole. Background technique [0002] AC asynchronous motors are widely used in the industrial field because they have the advantages of easy manufacturing, sturdiness and durability, and low price. However, asynchronous motors need to provide excitation current from the stator windings, and their power factor is not very high, and the efficiency of the motor is not high due to the existence of rotor copper loss, which is especially serious for small and medium-sized asynchronous motors or when the motor is lightly loaded. Compared with asynchronous motors, permanent magnet synchronous motors are equipped with permanent magnets on the rotor, which does not require external excitation, which can significantly improve the power factor; when the permanent magnet motors are operating in a steady...

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Problems solved by technology

However, after the basic magnetic circuit structure and main dimensions of the permanent magnet motor are determined, the rotor magnetic pole shape can only be improved by adjusting the variable eccentricity to improve the air-gap flux density waveform. The magnetic motor is closer to the sinusoidal air-gap magnetic field waveform, but the harmonic content in the no-load air-gap magnetic field of the permanent magnet motor obtained by this design method is still relatively high, and the harmonic magnetic field has a relatively large impact on the performance of the permanent magnet motor

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