Charging unit for a contactless transfer of electric power as well as a power absorbing device and a charging system

• US 6,781,346 B2
• Filed: 07/10/2002
• Issued: 08/24/2004
• Est. Priority Date: 07/10/2001
• Status: Active Grant

• Current Assignee: Friwo Gerätebau GmbH
• Original Assignee: Friwo Gerätebau GmbH
• Inventors: Reinhard, Arno, Schröeder, Ralf gen.Berghegger
• Primary Examiner(s): Tibbits, Pia
• Application Number:
  US10/192,824
• Publication Number:
  US 20030030530A1
• Time in Patent Office: 776 Days
• Field of Search: 320/108
• US Class Current: 320/108
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/10 using inductive coupling

Abstract

A charging system is used for contactless transfer of electric power from a charging unit to a mobile unit. The system includes a first substantially U-shaped ferrite core which is operable to be located within the charging unit. The first core includes a base area and two leg areas. Each leg area of the first core includes a pole face. A first winding is arranged on the base area of the first ferrite core. The system also includes a second substantially U-shaped ferrite core which is operable to be located within a mobile unit. The second core includes a base area and two leg areas. Each leg area of the second core includes a pole face. A second winding is arranged on the base area of the second ferrite core. The first ferrite core has larger cross-sectional dimensions than the second ferrite core.

Claims

1. A charging system used for a contactless transfer of electric power from a charging unit to a mobile unit, said the charging unit transferring by means of an alternating magnetic field electric power from at least one primary winding (120) arranged in said charging unit to at least one secondary winding (122) arranged in said mobile unit, the charging system comprising:

a first substantially U-shaped ferrite core arranged in said charging unit, the first ferrite core comprising

a first base having a first base length,

a first leg having a first leg length,

a second leg having a second leg length,

a first pole face positioned at an end of the first leg, and

a second pole face positioned at an end of the second leg,

a second substantially U-shaped ferrite core arranged in said mobile unit, the second ferrite core comprising

a second base having a second base length,

a third leg having a third leg length,

a fourth leg having a fourth leg length,

a third pole face positioned at an end of the third leg, and

a fourth pole face positioned at an end of the fourth leg, and

wherein the first base length is greater than the second base length, the first leg length and second leg length are greater than the third leg length and fourth leg length, and the first pole face and the second pole face are larger than the third pole face and the fourth pole face.

2. A system according to claim 1, wherein the ratio of the first and second pole faces to the third and fourth pole faces falls between 1.5:

1 and 2.5;

1.

3. A system according to one of the claim 1, wherein the secondary winding is arranged on the base of the second ferrite core and the primary winding is arranged on the base of the first ferrite core.

17. The system as set forth in claim 1, and wherein the first base length is greater than the first leg length and the second leg length, and the second base length is greater than the third leg length and the fourth leg length.

4. A charging system used for a contactless transfer of electric power from a charging unit to a mobile unit, the charging system comprising:

a first substantially U-shaped ferrite core operable to be located within the charging unit, the first ferrite core including a base, two legs, a pole face located on each leg, and a first winding;

a second substantially U-shaped ferrite core operable to be located within the mobile unit, the second ferrite core including a base, two legs, a pole face located on each leg, and a second winding; and

wherein the first ferrite core has larger cross-sectional dimensions than the second ferrite core.

5. A system according to claim 4, wherein the pole faces of the first ferrite core are larger than the pole faces of the second ferrite core.

6. A system according to claim 5, wherein a ratio of the pole faces of the first ferrite core to the pole faces of the second ferrite core is between about 1.5:

1 and about 2.5;

1.

7. A system according to claim 4, wherein the base of the first ferrite core and the base of the second ferrite core are both longer than the leg of the first ferrite core and the leg of the second ferrite core.

8. A system according to claim 4, wherein the first winding and the second winding are located on the base of the first ferrite core and the base of the second ferrite core, respectively.

9. A system according to claim 5, wherein the base of the first ferrite core and the base of the second ferrite core are longer than the legs of the first ferrite core and the legs of the second ferrite core, respectively.

10. A system according to claim 5, wherein the first winding and the second winding are located on the base of the first ferrite core and the base of the second ferrite core, respectively.

11. A system according to claim 6, wherein the base of the first ferrite core and the base of the second ferrite core are longer than the leg of the first ferrite core and the leg of the second ferrite core.

12. A system according to claim 6, wherein the first winding and the second winding are located on the base of the first ferrite core and the base of the second ferrite core, respectively.

13. A system according to claim 7, wherein the first winding and the second winding are located on the base of the first ferrite core and the base of the second ferrite core, respectively.

14. A method of transferring electric power from a primary winding to a secondary winding, the method comprising:

arranging the primary winding on a base of a first U-shaped ferrite core having a first leg and a second leg, wherein the base of the first ferrite core is longer than both the first leg and the second leg of the first ferrite core; and

arranging the second winding on a base of a second U-shaped ferrite core having a third leg and a fourth leg, wherein the base of the second ferrite core is longer than both the third leg and the fourth leg of the second ferrite core, and wherein the base of the first core is larger than the base of the second core.

15. The method as claimed in claim 14, further comprising configuring the first U-shaped ferrite core to have a larger dimensions than the second ferrite core.

16. The method as claimed in claim 14, further comprising configuring a first pole face located at an end of the first leg of the first ferrite core, a second pole face located at an end of the second leg of the first ferrite core, a third pole face located at an end of the third leg of the second ferrite core and a fourth pole face located at an end of the fourth leg of the second ferrite core, and wherein the first pole face and the second pole face are each larger than the third pole face and the fourth pole face.

18. A charging system used for a contactless transfer of electric power from a charging unit to a mobile unit, the charging system comprising:

a first substantially U-shaped ferrite core arranged in said charging unit, the first ferrite core comprising

a first base having a first base length,

a first winding arranged on the first base,

a first leg having a first leg length,

a second leg having a second leg length,

a first pole face positioned at an end of the first leg, and

a second pole face positioned at an end of the second leg,

a second substantially U-shaped ferrite core arranged in said mobile unit, the second ferrite core comprising

a second base having a second base length,

a second winding arranged on the second base,

a third leg having a third leg length,

a fourth leg having a fourth leg length,

a third pole face positioned at an end of the third leg, and

a fourth pole face positioned at an end of the fourth leg, and

wherein the first base length is greater than the second base length, the first leg length and second leg length are greater than the third leg length and fourth leg length, and the first pole face and the second pole face are larger than the third pole face and the fourth pole face; and

wherein the first base length is greater than the first leg length and the second leg length, and the second base length is greater than the third leg length and the fourth leg length.

19. A charging system used for a contactless transfer of electric power from a charging unit to a mobile unit, the charging system comprising:

a first substantially U-shaped ferrite core arranged in the charging unit, the first ferrite core comprising

a first base,

a first winding arranged on the first base,

a first leg, and

a first pole face positioned at an end of the first leg,

a second substantially U-shaped ferrite core arranged in the mobile unit, the second ferrite core comprising

a second base,

a second winding arranged on the second base,

a second leg, and

a second pole face positioned at an end of the second leg, and

wherein the second pole face does not completely overlap the first pole face when the charging system transfers electric power between the charging unit and the mobile unit.