Permanent magnet synchronous motor

Patent metadata

Field	Value
Publication number	US-10491065-B2
Application number	US-201415509219-A
Country	US
Kind code	B2
Filing date	Sep 11, 2014
Priority date	Sep 11, 2014
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

A permanent magnet synchronous motor includes a stator with a stator winding, a rotor with a rotor core rotatable relative to the stator, and a magnetic structure with at least one permanent magnet mounted to the rotor core. The magnetic structure produces a magnetic flux that flows between different magnetic poles of the magnetic structure through a main magnetic flux path that passes through the stator winding of the stator via an air gap and a leakage magnetic flux path that is located within the rotor core about an end portion of the permanent magnet near the air gap. The stator, the rotor and the magnetic structure being further configured to satisfy predetermined relationships in regards to the magnetic resistance of the main magnetic flux path and the leakage magnetic flux path, the magnetomotive force of the magnets and the stator.

First claim

What is claimed is:

1. A permanent magnet synchronous motor comprising:
a stator with a stator winding;
a rotor with a rotor core rotatable relative to the stator, the rotor being radially inwardly or outwardly disposed relative to the stator with an air gap therebetween; and
a magnetic structure with at least one permanent magnet mounted to the rotor core, the magnetic structure producing a magnetic flux that flows between different magnetic poles of the magnetic structure through a main magnetic flux path that passes through the stator winding of the stator via the air gap and a leakage magnetic flux path that is located within the rotor core about an end portion of the permanent magnet near the air gap,
the stator, the rotor and the magnetic structure being further configured to satisfy the following expressions while changing a magnetization state of the permanent magnet of the permanent magnet synchronous motor:

Vs
≥

Rg
+
Rs

Rr

⁢
Vm

η
=

Rg
+
Rs

Rb
+
Rg
+
Rs

≥
0.2

where Vs represents magnetomotive force of the stator winding, Vm represents magnetomotive force of the magnetic structure, Rg represents magnetic resistance of the air gap, Rs represents magnetic resistance of the stator along the main magnetic flux path, Rr represents magnetic resistance of the rotor core along the main magnetic flux path, Rb represents magnetic resistance of the rotor core along the leakage magnetic flux path, and η represents a ratio of a leakage magnetic flux of the magnetic flux that flows through the leakage magnetic flux path relative to a total magnetic flux of the magnetic flux that is produced by the magnetic structure.

2. The permanent magnet synchronous motor according to claim 1 , wherein
the leakage magnetic flux path extends between different magnetic poles of the permanent magnet.

3. The permanent magnet synchronous motor according to claim 2 , wherein
the rotor core has a magnetic barrier disposed between the permanent magnet and an adjacent permanent magnet that is adjacent to the permanent magnet, and a side opening circumferentially adjacent to the end portion of the permanent magnet, and
the leakage magnetic flux path extends on the rotor core between the magnetic barrier and the side opening.

4. A permanent magnet synchronous motor comprising:
a stator with a stator winding;
a rotor with a rotor core rotatable relative to the stator, the rotor being radially inwardly or outwardly disposed relative to the stator with an air gap therebetween; and
a magnetic structure with at least one permanent magnet mounted to the rotor core, the magnetic structure producing a magnetic flux that flows between different magnetic poles of the magnetic structure through a main magnetic flux path that passes through the stator winding of the stator via the air gap and a leakage magnetic flux path that is located within the rotor core about an end portion of the permanent magnet near the air gap,
the stator, the rotor and the magnetic structure being further configured to satisfy the following expressions:

Vs
≥

Rg
+
Rs

Rr

⁢
Vm

η
=

Rg
+
Rs

Rb
+
Rg
+
Rs

≥
0.2

where Vs represents magnetomotive force of the stator winding, Vm represents magnetomotive force of the magnetic structure, Rg represents magnetic resistance of the air gap, Rs represents magnetic resistance of the stator along the main magnetic flux path, Rr represents magnetic resistance of the rotor core along the main magnetic flux path, Rb represents magnetic resistance of the rotor core along the leakage magnetic flux path, and η represents a ratio of a leakage magnetic flux of the magnetic flux that flows through the leakage magnetic flux path relative to a total magnetic flux of the magnetic flux that is produced by the magnetic structure,
the leakage magnetic flux path extending between different magnetic poles of the permanent magnet,
the rotor core having a circumferential portion circumferentially extending and a radial portion radially extending from the circumferential portion,
the leakage magnetic flux path extending along the circumferential portion and the radial portion of the rotor core, and
the magnetic resistance of the circumferential portion calculated based on a magnetic path width and a magnetic path length of the leakage magnetic flux path along the circumferential portion being smaller than the magnetic resistance of the radial portion calculated based on a magnetic path width and a magnetic path length of the leakage magnetic flux path along the radial portion.

5. The permanent magnet synchronous motor according to claim 1 , wherein
the leakage magnetic flux path extends between different magnetic poles of the permanent magnet and an adjacent permanent magnet that is adjacent to the permanent magnet.

6. A permanent magnet synchronous motor comprising:
a stator with a stator winding;
a rotor with a rotor core rotatable relative to the stator, the rotor being radially inwardly or outwardly disposed relative to the stator with an air gap therebetween; and
a magnetic structure with at least one permanent magnet mounted to the rotor core, the magnetic structure producing a magnetic flux that flows between different magnetic poles of the magnetic structure through a main magnetic flux path that passes through the stator winding of the stator via the air gap and a leakage magnetic flux path that is located within the rotor core about an end portion of the permanent magnet near the air gap,
the stator, the rotor and the magnetic structure being further configured to satisfy the following expressions:

Vs
≥

Rg
+
Rs

Rr

⁢
Vm

η
=

Rg
+
Rs

Rb

Assignees

• Nissan Motor
• Wisconsin Alumni Res Found

Inventors

• Sasaki Kensuke
• Fukushige Takashi
• Kato Takashi
• Lorenz Robert D
• Athavale Apoorva

Classifications

• H02K1/276

  Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM] · CPC title

• H02K21/14

  with magnets rotating within the armatures · CPC title

• H02K1/2766 Primary

  having a flux concentration effect · CPC title

• H02K21/02

  Details · CPC title

• G01N27/82

  for investigating the presence of flaws · CPC title