JP2012034473A - Rotor of permanent magnet synchronous motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that iron loss of a stator increases since spatial harmonic is included in magnetomotive force distribution of a permanent magnet embedded inside a rotor of an embedded magnet synchronous motor and high-order harmonic magnetic flux is interlinked with stator teeth in the case of motor of distributed winding.SOLUTION: An opening is formed on a gap-side of the magnet embedded in the rotor and magnetomotive force distribution of the rotor is brought close to a sine wave. The harmonic magnetic flux interlinked with the stator reduces and the iron loss of the stator can be reduced.

Description

  The present invention relates to a rotor of a permanent magnet synchronous motor.

A permanent magnet synchronous motor is an electric motor mainly used for industrial equipment. There are an embedded magnet synchronous motor in which a permanent magnet is embedded in the rotor and a surface magnet synchronous motor in which a permanent magnet exists on the rotor surface.
Permanent magnet synchronous motors have the advantage that they are more efficient than conventional induction motors.

  However, the magnetomotive force distribution of the permanent magnet inside the rotor contains spatial harmonics, and in the case of distributed winding motors, higher-order harmonic magnetic fluxes are linked to the stator teeth, so There was a problem of increasing iron loss.

  As an improvement measure, there is a method in which a gap is provided in the corner portion of the magnet inside the rotor, the magnetic flux at the corner of the magnetic pole is weakened, and the magnetomotive force distribution of the permanent magnet is made close to a sine wave.

JP 2002-209350 A

“Analysis of Iron Loss and Magnet Eddy Current Loss of Concentrated Winding IPM Motor”, Katsumi Yamazaki and Tsubasa Hamada, IEEJ Transactions D, Vol. 128, No. 5, p. 678

  The problem to be solved is that the magnetomotive force distribution of the rotor of the permanent magnet synchronous motor is not a sine wave.

  The present invention is characterized in that, in order to reduce the core loss of the distributed winding stator core, a gap is provided in the rotor, the magnetic flux is collected at the center of the magnetic pole, and the magnetomotive force is made close to a sine wave.

  According to the first aspect of the present invention, in the rotor of the permanent magnet synchronous motor, the rotor includes a permanent magnet embedded in the rotor core, and there is a gap between the magnet and the gap, The rotor of a permanent magnet motor is characterized in that the air gap is a space having a shape in which the magnetic flux of the magnet is collected at the center of the magnetic pole, and the magnetomotive force distribution generated by the rotor approaches a sine wave.

  According to a second aspect of the present invention, in the rotor of a permanent magnet synchronous motor according to the first aspect, two gaps are provided on the gap side of the magnet.

  According to a third aspect of the present invention, a plurality of the gaps are provided on the gap side of the magnet so that the magnet magnetomotive force distribution produced by the rotor is made closer to a sine wave. Magnet synchronous motor rotor.

  According to invention of Claim 4, the said space | gap penetrates to the rotor surface, The rotor of the permanent-magnet synchronous motor of Claim 1 characterized by the above-mentioned.

  According to the invention of claim 5, the rotor of the permanent magnet synchronous motor according to claim 1, wherein the gap penetrates to the hole in which the magnet is embedded.

  According to a sixth aspect of the present invention, the permanent magnet synchronous motor rotor according to the first aspect, wherein the magnet is divided into one or a plurality in the circumferential direction per pole.

  In the rotor of the permanent magnet synchronous motor of the present invention, a gap is provided on the gap side of the magnet so that the magnetomotive force distribution of the magnet approximates a sine wave, so that the harmonic magnetic flux linked to the stator is reduced. There is an advantage that iron loss of the stator can be reduced.

It is explanatory drawing when two space | gap is provided. Example 1 This is a magnetomotive force distribution of a rectangular wave having two stages. It is explanatory drawing when four space | gap is provided. (Example 2) This is a magnetomotive force distribution of a rectangular wave having three stages. It is explanatory drawing when a several space | gap is provided. (Example 3) It is explanatory drawing when two notches are provided from the rotor surface. Example 4 It is explanatory drawing when two notches are provided from the magnet hole. (Example 5) This is one pole of a permanent magnet synchronous motor. It is a magnetomotive force distribution of a square wave. It is a magnet magnetomotive force distribution of a sine wave.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 8 is a diagram showing one pole of the permanent magnet synchronous motor. In the rotor as shown in FIG. 8, the magnetomotive force distribution of the magnet looks like a rectangular wave as shown in FIG. In the rotor according to the present invention, by providing a gap on the gap side of the permanent magnet, the magnetic flux of the permanent magnet is concentrated at the center of the magnetic pole, and the magnetomotive force distribution of the magnet is made close to a sine wave as shown in FIG.

  FIG. 1 is a diagram showing an example in which two gaps are provided.

  An air gap is formed so as to collect the magnetic flux of the magnet from the magnet toward the rotor surface. The magnetomotive force waveform has two steps as shown in FIG. 2 and approaches a sine wave.

  The two air gaps provide symmetrical lines from the rotor center to the magnetic pole center.

  FIG. 3 is a diagram showing an embodiment in which four gaps are provided.

  An air gap is formed so as to collect the magnetic flux of the magnet from the magnet toward the rotor surface. The magnetomotive force waveform has three stages as shown in FIG. 4 and approaches a sine wave.

  The four air gaps are provided symmetrically on the inner two and the outer two, respectively, from the rotor center to the magnetic pole center.

  FIG. 5 is a diagram showing an embodiment in which a plurality of gaps are provided.

  A plurality of gaps are provided so as to collect the magnetic flux of the magnet from the magnet toward the rotor surface. The greater the number of voids, the closer the magnetomotive force of the magnet is to a sine wave.

  The plurality of gaps provide symmetrical lines from the rotor center to the magnetic pole center.

  FIG. 6 is a diagram showing an example in which the gap is extended to the stator surface to form a notch.

  A notch having a shape that collects the magnetic flux of the magnet from the magnet toward the rotor surface is provided.

  The two notches provide symmetrical lines from the rotor center to the magnetic pole center.

  FIG. 7 is a view showing an embodiment in which the gap is extended to the hole for embedding the magnet.

  A notch having a shape that collects the magnetic flux of the magnet from the magnet toward the rotor surface is provided.

  The two notches provide symmetrical lines from the rotor center to the magnetic pole center.

  According to the present invention, the magnetomotive force of the rotor of the permanent magnet synchronous motor can be made close to a sine wave. Since the loss of the stator can be reduced, it can be applied to permanent magnet synchronous motors in general.

DESCRIPTION OF SYMBOLS 1 Rotor 2 Stator 3 Coil 4 Permanent magnet 5 Air gap 6 Notch 7 Square wave magnet magnetomotive force distribution 8 Sinusoidal magnet magnetomotive force distribution 9 Rectangular wave magnet magnetomotive force distribution with 2 steps 10 Rectangular with 3 steps Magnetomotive force distribution of wave

Claims (6)

  In a rotor of a permanent magnet synchronous motor, the rotor includes a permanent magnet embedded in a rotor core, and there is a gap between the magnet and the gap, and the gap uses the magnetic flux of the magnet as the center of the magnetic pole. A rotor of a permanent magnet motor, wherein the magnet magnetomotive force distribution generated by the rotor approaches a sine wave.   The rotor of a permanent magnet synchronous motor according to claim 1, wherein two gaps are provided on the gap side of the magnet.   The rotor of a permanent magnet synchronous motor according to claim 1, wherein a plurality of the gaps are provided on the gap side of the magnet so that the magnetomotive force distribution generated by the rotor is made closer to a sine wave.   The rotor of a permanent magnet synchronous motor according to claim 1, wherein the gap penetrates to the rotor surface.   The rotor of a permanent magnet synchronous motor according to claim 1, wherein the gap penetrates to a hole in which a magnet is embedded.   The rotor of a permanent magnet synchronous motor according to claim 1, wherein the magnet is divided into one piece or a plurality of pieces in the circumferential direction per pole.

Images