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

• US 20030030530A1
• Filed: 07/10/2002
• Published: 02/13/2003
• Est. Priority Date: 07/10/2001
• Status: Active Grant

• Current Assignee: Friwo Gerätebau GmbH
• Original Assignee: Friwo Gerätebau GmbH
• Inventors: Schroeder, Ralf gen.Berghegger, Reinhard, Arno
• Granted Patent: US 6,781,346 B2
• Time in Patent Office: Days
• US Class Current: 336/182
• 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

The present invention relates to a charging unit used for a contactless transfer of electric power to a mobile unit, a complementary power absorbing device and a charging system. The charging unit transfers by means of an alternating magnetic field electric power from at least one primary winding to at least one secondary winding arranged in said mobile unit, and comprises a substantially U-shaped ferrite core which comprises a base area and two leg areas, each provided with a pole face, and which has the primary winding arranged thereon. In order to provide a charging unit for a contactless transfer of electric power to a mobile unit, an associated power absorbing device and a charging system, which permit an improved magnetic coupling between the primary side and the secondary side and consequently an improved power transfer, the primary winding is arranged on the base area of the U-shaped ferrite core. According to an advantageous further development, the base area of the U-shaped ferrite core can be longer than the leg areas so that the ferrite core has a substantially elongate structural design.

Claims

1. A charging unit used for a contactless transfer of electric power to a mobile unit, the charging unit transferring by means of an alternating magnetic field electric power from at least one primary winding (120) to at least one secondary winding (122) arranged in said mobile unit, and comprising a substantially U-shaped ferrite core (100) which comprises a base area (102) and two leg areas (104, 106), each provided with a pole face (108), and which has the primary winding (120) arranged thereon, characterized in that

the primary winding (120) is arranged on the base area (102) of the U-shaped ferrite core (100).

2. A charging unit according to claim 1, characterized in that the base area (102) of the U-shaped ferrite core (100) is longer than the leg areas (104, 106) so that the ferrite core (100) has a substantially elongate structural design.

3. A charging unit according to claim 2, characterized in that the length ratio of the base area (102) to the leg area (104, 106) assumes values between 2:

1 and 4;

1.

4. A power absorbing device in a mobile unit used for a contactless absorption of electric power, said device absorbing by means of an alternating magnetic field electric power from at least one primary winding (120) arranged in the charging unit through at least one secondary winding (122) arranged in said mobile unit, and comprising a substantially U-shaped ferrite core (101) which comprises a base area (102) and two leg areas (104, 106), each provided with a pole face (108), and which has the secondary winding (122) arranged thereon, characterized in that

the secondary winding (122) is arranged on the base area (102) of the U-shaped ferrite core (101).

5. A device according to claim 4, characterized in that the base area (102) of the U-shaped ferrite core (101) is longer than the leg areas (104, 106) so that the ferrite core (101) has a substantially elongate structural design.

6. A device according to claim 5, characterized in that the length ratio of the base area (102) to the leg area (104, 106) assumes values between 2:

1 and 4;

1.

7. 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, and said charging unit as well as said mobile unit comprising a substantially U-shaped ferrite core (100, 101) which comprises a base area (102) and two leg areas (104, 106), each provided with a pole face (108), characterized in that

the primary-side ferrite core (100) has larger cross-sectional dimensions than the secondary-side ferrite core (101).

8. A system according to claim 7, characterized in that the pole faces (108) of the primary-side ferrite core (100) have larger dimensions than the pole faces (108) of the secondary-side ferrite core (101).

9. A system according to claim 8, characterized in that the ratio of the areas of the primary-side pole faces to the areas of the secondary-side pole faces assumes values between 1.5:

1 and 2.5;

1.

10. A system according to one of the claims 7 to 9, characterized in that the base areas (102) of the U-shaped ferrite cores (100, 101) are longer than the leg areas (104, 106) thereof so that both ferrite cores (100, 101) have a substantially elongate and flat structural design.

11. A system according to one of the claims 7 to 10, characterized in that the secondary winding (122) and/or the primary winding (120) are provided on the base areas (102) of the U-shaped ferrite cores (100, 101).