Method and apparatus for coupling cancellation

Patent metadata

Field	Value
Publication number	US-9825522-B2
Application number	US-201514682448-A
Country	US
Kind code	B2
Filing date	Apr 9, 2015
Priority date	Apr 9, 2015
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

A DC to DC power converter includes a switching circuit and an LC filter configured to reduce parasitic inductance. The LC filter includes an inductor, capacitor, and a coil positioned and oriented relative to and electrically connected with the capacitor. The coil positioned with the capacitor provides the ripple current caused by operation of the switching circuitry to flow through the capacitor and coil with opposite direction. The ripple current flowing through the coil attenuates a magnetic field generated by the capacitor while reducing parasitic inductance of the capacitor.

First claim

What is claimed is:

1. A DC to DC power converter comprising:
an LC filter including an inductor, capacitor, and a coil positioned and oriented relative to and electrically connected with the capacitor such that ripple current caused by operation of switching circuitry flows through the capacitor and coil with opposite direction to attenuate a magnetic field generated by the capacitor to reduce parasitic inductance of the capacitor.

2. The converter of claim 1 , wherein the capacitor and coil are stacked on top of each other.

3. The converter of claim 1 , wherein the coil is electrically connected with the inductor.

4. The converter of claim 1 , wherein a number of turns of the coil is based on a size of the capacitor and a desired coupling between the parasitic inductance of the capacitor and an inductance of the coil.

5. The converter of claim 1 , wherein a diameter of the coil is based on a size of the capacitor and a desired coupling between the parasitic inductance of the capacitor and an inductance of the coil.

6. The converter of claim 1 , wherein the LC filter is connected to at least one of an input of the switching circuitry and an output of the switching circuitry.

7. The converter of claim 1 , wherein the coil is electrically connected before the inductor or after the inductor.

8. An LC filter comprising:
an inductor;
a capacitor electrically connected to the inductor; and
a coil electrically connected in series and stacked on the capacitor so that ripple current flow through the capacitor and coil are in opposite directions resulting in magnetic field offset between the capacitor and coil to reduce a parasitic inductance of the capacitor, the coil having a predefined number of turns and diameter based on a size of the capacitor.

9. The filter of claim 8 , wherein the capacitor and coil are stacked on top of each other.

10. The filter of claim 8 , wherein the coil is electrically connected with the inductor.

11. The filter of claim 8 , wherein the number of turns of the coil is based on the size of the capacitor and a desired coupling between the parasitic inductance of the capacitor and an inductance of the coil.

12. The filter of claim 8 , wherein the diameter of the coil is based on the size of the capacitor and a desired coupling between the parasitic inductance of the capacitor and an inductance of the coil.

13. The filter of claim 8 , wherein the coil is connected at an input of switching circuitry.

14. The filter of claim 8 , wherein the coil is connected at an output of switching circuitry.

15. A method for attenuating a magnetic field at a power convertor, the method comprising:
attenuating a magnetic field generated by a capacitor of an LC filter including an inductor and a coil by directing a ripple current from the capacitor to the coil such that the ripple current flows through the capacitor and coil in opposite directions to reduce parasitic inductance of the capacitor.

16. The method of claim 15 , wherein the capacitor and coil are stacked on top of each other.

17. The method of claim 15 , wherein a number of turns of the coil is based on a size of the capacitor and a desired coupling between the parasitic inductance of the capacitor and an inductance of the coil.

18. The method of claim 15 , wherein a diameter of the coil is based on a size of the capacitor and a desired coupling between the parasitic inductance of the capacitor and an inductance of the coil.

19. The method of claim 15 , further comprising connecting the coil at an input of switching circuitry.

20. The method of claim 15 , further comprising connecting the coil at an output of switching circuitry.

Assignees

• Ford Global Tech Llc

Inventors

• Elshaer Mohamed
• Chen Chingchi

Classifications

• H03H7/09

  Filters comprising mutual inductance · CPC title

• H02M1/16

  Means for providing current step on switching, e.g. with saturable reactor · CPC title

• H02H7/10

  for converters; for rectifiers {(forming part of the control circuit of the converter, see the relevant group in H02M)} · CPC title

• H02M3/156

  with automatic control of output voltage or current, e.g. switching regulators · CPC title

• H02M1/14 Primary

  Arrangements for reducing ripples from DC input or output · CPC title