Current-controlled variable inductor

• US 8,120,457 B2
• Filed: 04/09/2010
• Issued: 02/21/2012
• Est. Priority Date: 04/09/2010
• Status: Active Grant

• Current Assignee: Delta Electronics Incorporated
• Original Assignee: Delta Electronics Incorporated
• Inventors: Hu, Yuequan, Huber, Laszlo, Jovanović, Milan
• Primary Examiner(s): Nguyen, Tuyen
• Application Number:
  US12/757,296
• Publication Number:
  US 20110248812A1
• Time in Patent Office: 683 Days
• Field of Search: 336/170, 336/173, 336/178, 336180-184, 336/212, 336220-223, 336214-215
• US Class Current: 336/178
• CPC Class Codes: H01F 2029/143 with control winding for generating magnetic bias
• CPC Class Codes: H01F 29/14 with variable magnetic bias amplitude modulation by means of variable impedance element H03C1/08 ; magnetic amplifiers H03F; circuits for automatic telephonic communication H04M3/00

Abstract

A variable inductor comprises one or more magnetic cores providing magnetic flux paths. An inductor coil is wound around one or more inductor sections of the one or more magnetic cores. An inductor magnetic flux flows through one or more closed flux paths along the inductor sections of the magnetic core. A control coil is wound around one or more control sections of the one or more magnetic cores. A control magnetic flux flows through one or more closed flux paths along the control sections of the magnetic core. Under this arrangement, the inductor magnetic flux substantially does not flow through the control sections of the magnetic core and the control magnetic flux substantially does not flow through the inductor sections of the magnetic core. The closed flux paths associated with the inductor magnetic flux and the closed flux paths associated with the control magnetic flux share one or more common sections of the magnetic core not including the control sections and inductor sections. The inductance of said variable inductor is varied by varying said control magnetic flux.

Claims

1. A variable inductor comprising:

one or more magnetic cores providing magnetic flux paths;

an inductor coil wound around one or more inductor sections of the one or more magnetic cores, wherein an inductor magnetic flux flows through one or more closed flux paths along the inductor sections of the magnetic core; and

a control coil wound around one or more control sections of the one or more magnetic cores, wherein a control magnetic flux flows through one or more closed flux paths along the control sections of the magnetic core, wherein the inductor magnetic flux substantially does not flow through the control sections of the magnetic core, wherein the control magnetic flux substantially does not flow through the inductor sections of the magnetic core, wherein the closed flux paths associated with the inductor magnetic flux and the closed flux paths associated with the control magnetic flux share one or more common sections of the magnetic core that do not include the control sections and inductor sections, and wherein the inductance of said variable inductor is varied by varying said control magnetic flux.

2. The variable inductor of claim 1, wherein variations in the control magnetic flux vary the effective permeability of the common sections of the magnetic core.

3. The variable inductor of claim 2, wherein variations in the effective permeability of the common sections of the magnetic core vary the inductance of said variable inductor.

4. The variable inductor of claim 1, wherein increasing the control magnetic flux decreases the inductance of said variable inductor.

5. The variable inductor of claim 1, wherein decreasing the control magnetic flux increases the inductance of said variable inductor.

6. The variable inductor of claim 1, further comprising one or more air gaps defined by the magnetic core along the closed flux paths associated with the inductor magnetic flux.

7. The variable inductor of claim 1, further comprising one or more air gaps defined by the magnetic core along the closed flux paths associated with the control magnetic flux.

8. The variable inductor of claim 1, further comprising a control circuit for varying the inductance of said variable inductor.

9. The variable inductor of claim 8, wherein said control circuit varies a control current associated with said control magnetic flux.

10. The variable inductor of claim 9, wherein said control circuit increases the control current to decrease the inductance of said variable inductor.

11. The variable inductor of claim 9, wherein said control circuit decreases the control current to increase the inductance of said variable inductor.

12. The variable inductor of claim 9, wherein said control circuit varies the control current based on the line voltage.

13. The variable inductor of claim 9, wherein said control circuit varies the control current based on the load current.

14. A power supply comprising:

a converter having a variable inductor, said inductor comprising;

one or more magnetic cores providing magnetic flux paths;

an inductor coil wound around one or more inductor sections of the one or more magnetic cores, wherein an inductor magnetic flux flows through one or more closed flux paths along the inductor sections of the magnetic core; and

a control coil wound around one or more control sections of the one or more magnetic cores, wherein a control magnetic flux flows through one or more closed flux paths along the control sections of the magnetic core,

wherein the inductor magnetic flux substantially does not flow through the control sections of the magnetic core,

wherein the control magnetic flux substantially does not flow through the inductor sections of the magnetic core,

wherein the closed flux paths associated with the inductor magnetic flux and the closed flux paths associated with the control magnetic flux share one or more common sections of the magnetic core that does not include the control sections and inductor sections,

wherein the inductance of said variable inductor is varied by varying said control magnetic flux.

15. The power supply of claim 14, wherein the inductance of said variable inductor is adjusted based on the line voltage of the power supply.

16. The power supply of claim 14, wherein the inductance of said variable inductor is adjusted based on the load current of the power supply.

17. The power supply of claim 14, wherein said converter is used for regulation of power.

18. The power supply of claim 14, wherein said converter is used for power factor correction.