Permanent magnet excited synchronous machine with embedded magnets

• US 9,083,218 B2
• Filed: 07/23/2010
• Issued: 07/14/2015
• Est. Priority Date: 09/18/2009
• Status: Active Grant

• Current Assignee: Brusa Technology AG
• Original Assignee: BRUSA Elektronik AG
• Inventors: Mathoy, Arno
• Primary Examiner(s): NGUYEN, HANH N
• Application Number:
  US13/390,632
• Publication Number:
  US 20120175989A1
• Time in Patent Office: 1,817 Days
• Field of Search: 310/156.53, 310/156.56, 310/156.57
• US Class Current: 1/1
• CPC Class Codes: H02K 1/2766 having a flux concentration effect

Abstract

A permanent magnet excited synchronous machine (1) with embedded magnets, which is particularly suitable for range extender generator. It includes stator (2) and rotor (3) being provided with exciter magnets (7). The rotor (3) has at least two rotor poles (4), each is provided with one exciter magnet (7). In order to increase the magnetic torque limit of the synchronous machine (1)—in each rotor pole (4) at least one, preferably several selective magnetic flux barriers, preferably as substantially radial slots (8) being parallel with the main pole flux is/are provided in the area of the pole shoe.

Claims

1. A permanent magnet excited synchronous machine comprising:

a stator, said stator having a plurality of circumferential stator teeth;

a rotor configured to rotate in said stator;

a rotary shaft supporting said rotor for rotation on its axis;

a salient pole on said rotor, said salient pole including a shank, said salient pole including a shoe on said shank;

a rectangular cross-section cavity in said salient pole, said rectangular cavity having a cross-section major axis coincident with a chord of a circle delimited by the rotor diameter, said rectangular cavity having a radially-outer top wall parallel to said chord and said major axis;

an exciter permanent magnet in said rectangular cavity;

a plurality of selective flux barrier slots in said salient pole, said plurality of slots disposed radially outwardly of said permanent magnet and between said radially-outer top wall of said rectangular cavity and an external surface of said shoe;

said plurality of slots disposed in a fan arrangement relative to said chord so that slots of said plurality that are located circumferentially nearer to a main axis of said pole are inclined at a lesser absolute value of inclination angle relative to the main pole axis than are others of said slots relatively located circumferentially farther from the main pole axis; and

,

said plurality of slots is a number selected to correspond to the number of said stator teeth radially opposite to said shoe.

2. A permanent magnet excited synchronous machine as claimed in claim 1, further comprising:

a flux barrier permanent magnet in one of said plurality of slots.

3. The permanent magnet excited synchronous machine as claimed in claim 2, wherein:

said flux barrier permanent magnet is wedge-shaped in longitudinal cross-section and tapered in a radial direction toward said rotary shaft.

4. The permanent magnet excited synchronous machine as claimed in claim 2, wherein:

said flux barrier permanent magnet fills no more than a radially-inner third of said one of said plurality of slots.

5. The permanent magnet excited synchronous machine as claimed in claim 2, wherein:

the north-south pole orientation of said flux barrier permanent magnet is disposed transversely to said slot.

6. A permanent magnet excited synchronous machine as claimed in claim 2, further comprising:

a plurality of flux barrier permanent magnets, each respective one of said plurality of flux barrier permanent magnets disposed in a respective one of said plurality of slots.

7. The permanent magnet excited synchronous machine as claimed in claim 1, wherein:

each of said slots has a constant width over its respective length.

8. The permanent magnet excited synchronous machine as claimed in claim 7, wherein:

a first ratio, of a minimum distance between adjacent ones of said plurality of slots to width of said slots, is at least identical or greater than a second ratio, of stator tooth width to width of stator gap between adjacent ones of said plurality of stator teeth.

9. A permanent magnet excited synchronous machine comprising:

a stator, said stator having a plurality of circumferential stator teeth;

a rotor configured to rotate in said stator;

a rotary shaft supporting said rotor for rotation on its axis;

a salient pole on said rotor, said salient pole including a shank, said salient pole including a shoe on said shank;

a rectangular cross-section cavity in said salient pole, said rectangular cavity having a cross-section major axis coincident with a chord of a circle delimited by the rotor diameter, said rectangular cavity having a radially-outer top wall parallel to said chord and said major axis;

an exciter permanent magnet in said rectangular cavity;

a plurality of selective flux barrier slots in said salient pole, said plurality of slots disposed radially outwardly of said permanent magnet and between said radially-outer top wall of said rectangular cavity and an external surface of said shoe;

a plurality of flux barrier permanent magnets, each respective one of said plurality of flux barrier permanent magnets disposed in a respective one of said plurality of slots;

said flux barrier permanent magnets being wedge-shaped in their respective longitudinal cross-sections and tapered in a radial direction toward said rotary shaft; and

,

said plurality of slots is a number selected to correspond to the number of said stator teeth radially opposite to said shoe.

10. The permanent magnet excited synchronous machine as claimed in claim 9, wherein:

said plurality of flux barrier permanent magnets each fills no more than a radially-inner third of the respective slot in which it is disposed.

11. The permanent magnet excited synchronous machine as claimed in claim 9, wherein:

the north-south pole orientation of each of said flux barrier permanent magnets is disposed transversely to the respective slot in which it is disposed.

12. The permanent magnet excited synchronous machine as claimed in claim 9, wherein:

each of said slots has a constant width over its respective length.

13. The permanent magnet excited synchronous machine as claimed in claim 9, wherein:

a first ratio, of a minimum distance between adjacent ones of said plurality of slots to width of said slots, is at least identical or greater than a second ratio, of stator tooth width to width of stator gap between adjacent ones of said plurality of stator teeth.

14. The permanent magnet excited synchronous machine as claimed in claim 9, wherein:

said plurality of slots are disposed in a fan arrangement relative to said chord so that slots of said plurality that are located circumferentially nearer to a main axis of said pole are inclined at a lesser absolute value of inclination angle relative to the main pole axis than are others of said slots relatively located circumferentially farther from the main pole axis.

15. A permanent magnet excited synchronous machine comprising:

a stator;

a rotor configured to rotate in said stator;

at least two rotor poles on said rotor;

a respective exciter magnet disposed in each respective one of said at least two rotor poles;

each of said at least two rotor poles respectively having a respective plurality of openings formed as selective flux barriers configured to increase magnetic torque limit and reduce rotor pole cross-flux, said selective flux barriers each being in the form of a respective radially extending slot having a constant width over substantially its entire length;

said stator having a plurality of circumferential stator teeth; and

,

said plurality of slots is a number selected to correspond to the number of said stator teeth radially opposite to said shoe.

16. A permanent magnet excited synchronous machine comprising:

a stator;

a rotor configured to rotate in said stator;

at least two rotor poles on said rotor;

a respective exciter magnet disposed in each respective one of said at least two rotor poles;

each of said at least two rotor poles respectively having a respective plurality of openings formed as selective flux barriers configured to increase magnetic torque limit and reduce rotor pole cross-flux, said selective flux barriers each being in the form of a respective radially extending slot having a constant width over substantially its entire length;

said stator having a plurality of circumferential stator teeth; and

,

a first ratio, of minimum distance between adjacent ones of said plurality of slots to width of said slots, is greater than or equal to a second ratio, of stator tooth width to width of a stator gap between adjacent ones of said plurality of stator teeth.

17. A permanent magnet excited synchronous machine comprising:

a stator;

a rotor configured to rotate in said stator;

at least two rotor poles on said rotor;

a respective exciter magnet disposed in each respective one of said at least two rotor poles;

each of said at least two rotor poles respectively having a respective plurality of openings formed as selective flux barriers configured to increase magnetic torque limit and reduce rotor pole cross-flux, said selective flux barriers each being in the form of a respective radially extending slot having a constant width over substantially its entire length; and

,

a flux barrier permanent magnet in at least one of said plurality of slots.

18. The permanent magnet excited synchronous machine as claimed in claim 17, wherein:

said flux barrier permanent magnet is wedge-shaped in longitudinal cross-section and tapered in a radial direction toward said rotary shaft.

19. The permanent magnet excited synchronous machine as claimed in claim 17, wherein:

said flux barrier permanent magnet fills no more than a radially-inner third of said at least one of said plurality of slots.

20. The permanent magnet excited synchronous machine as claimed in claim 17, wherein:

a north-south pole position of said flux barrier permanent magnet in said at least one of said plurality of slots is arranged transversely to a length of said at least one of said plurality of slots.

21. A permanent magnet excited synchronous machine as claimed in claim 17, further comprising:

each respective one of said slots being formed as a respective longitudinal opening having respective parallel side surfaces; and

,

said at least two rotor poles are salient poles.