Inductive coupling system with capacitive parallel compensation of the mutual self-inductance between the primary and the secondary windings

• US 20020130642A1
• Filed: 02/27/2002
• Published: 09/19/2002
• Est. Priority Date: 03/02/2001
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Van Der Veen, Johannes Lambertus Franciscus, Duarte, Jorge Luiz, Ettes, Wilhelmus Gerardus Maria
• Granted Patent: US 6,498,456 B2
• Time in Patent Office: Days
• US Class Current: 323/247
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10

Abstract

To improve the performance of an inductive coupling system, the magnetic coupling between the primary (4) and secondary (8) windings is increased by adding auxiliary windings (26,28) on the primary (2) and/or secondary (6) yokes of the assembly near the air gap (18) between the yokes. Capacitors (30,32) are connected to the auxiliary windings (26, 28) which, together with the inductance of the auxiliary windings, resonate at the operating frequency of the primary AC voltage (Vp). The effect is an improved magnetic coupling between the primary and secondary windings (4, 8) without increasing the size of the magnetic assembly.

Claims

1. An inductive coupling system comprising:

a magnetizable core with a primary yoke (2) which is provided with a primary winding (4) for connecting a primary AC voltage (Vp), and a secondary yoke (6) which is provided with a secondary winding (8), which primary yoke (2) and secondary yoke (6) have corresponding end surfaces (10, 14;

12, 16) for magnetic energy transfer between the primary yoke (2) and the secondary yoke (6), characterized in that said inductive coupling system comprises means (Cm) for capacitive parallel compensation of a mutual self-inductance (Lm) of the coupling system at the frequency of the primary AC voltage (Vp).

2. An inductive coupling system as claimed in claim 1, characterized in that the means for capacitive parallel compensation comprise an auxiliary winding (26) which is arranged near at least one (10) of said end surfaces, to which auxiliary winding a capacitor (30) is connected which resonates with the auxiliary winding at the frequency of the primary AC voltage (Vp).

3. An inductive coupling system as claimed in claim 2, characterized in that the primary yoke (2) and the secondary yoke (6) are 2-legged, the primary winding (4) being arranged in the central portion of the primary yoke (2) and the auxiliary winding (26, 28) and the capacitor (30, 32) being arranged near each (10, 12) of the two end surfaces of the primary yoke (2).

4. An inductive coupling system as claimed in claim 3, characterized in that the secondary winding (8) is arranged in the central portion of the secondary yoke (6), and the auxiliary winding (34, 36) and the capacitor (38, 40) are additionally arranged near each (14, 16) of the two end surfaces of the secondary yoke (6).

5. An inductive coupling system as claimed in claim 2, characterized in that the primary yoke (2) and the secondary yoke (6) are 2-legged, the primary winding (4) being arranged on one leg of the primary yoke (2) and the auxiliary winding (26) and the capacitor (30) being arranged near the end surface (10) of the other leg of the primary yoke (2).

6. An inductive coupling system as claimed in claim 5, characterized in that the secondary winding (8) is arranged on one leg of the secondary yoke (6), and the auxiliary winding (36) and the capacitor (40) are additionally arranged near the end surface (16) of the other leg of the secondary yoke (6).

7. An inductive coupling system as claimed in claim 2, characterized in that the primary yoke (54) and the secondary yoke (70) are E-shaped, having a central leg (50;

68) and two outer legs (56, 58;

80, 82), while the primary winding (50) is arranged on the central leg (52) of the primary yoke (54), and the auxiliary winding (60;

62) and the capacitor (64;

66) are arranged near each of the two end surfaces of the two outer legs (56;

58) of the primary yoke (54).

8. An inductive coupling system as claimed in claim 7, characterized in that the secondary winding is arranged in parts (76;

78) on the two outer legs (80;

82) of the secondary yoke (70), and the auxiliary winding (72) and the capacitor (74) are additionally arranged near the end surface of the central leg (68) of the secondary yoke (70).

9. A combination of a rechargeable appliance (90) and a stand (92) for placement of the rechargeable appliance (90) in the stand (92) for the purpose of recharging a rechargeable battery (100) in the rechargeable appliance (90), characterized in that the combination is provided with an inductive coupling system as claimed in any one of the preceding claims, wherein the primary yoke (2) and the primary winding (4) are accommodated in the stand (92) and the secondary yoke (6) and the secondary winding (8) are accommodated in the rechargeable appliance (90).