Electrolytic capacitor reformation systems and methods

Patent metadata

Field	Value
Publication number	US-9156343-B2
Application number	US-201213418878-A
Country	US
Kind code	B2
Filing date	Mar 13, 2012
Priority date	Dec 27, 2011
Publication date	Oct 13, 2015
Grant date	Oct 13, 2015

Abstract

An electrolytic capacitor reformation system for a vehicle includes an electrolytic capacitor, a motor driver module, a switching device, a resistor, and a switching control module. The electrolytic capacitor receives power from a battery of the vehicle. The motor driver module receives power from the electrolytic capacitor and drives an electric motor of the vehicle. The switching device and the resistor are connected in series in a current path between the battery and the electrolytic capacitor. The resistor limits current flow through the current path. The switching control module selectively transitions the switching device to a closed state to reform the electrolytic capacitor.

First claim

What is claimed is:

1. An electrolytic capacitor reformation system for a vehicle, comprising:
an electrolytic capacitor that receives power from a battery of the vehicle, wherein defects form in an oxide of the electrolytic capacitor when the electrolytic capacitor has not received power for at least a predetermined period;
a motor driver module that receives power from the electrolytic capacitor and that drives an electric motor of the vehicle;
a switching device and a resistor that are connected in series in a current path between the battery and the electrolytic capacitor, wherein the resistor limits current flow through the current path; and
a switching control module that varies a duty cycle of the switching device as a function of a leakage current through the electrolytic capacitor to cure defects formed in the oxide of the electrolytic capacitor and,
wherein the switching control module determines an equivalent series resistance (ESR) of the electrolytic capacitor and initiates curing of the defects formed in the oxide of the electrolytic capacitor in response to a determination that the ESR of the electrolytic capacitor is less than a predetermined resistance.

2. The electrolytic capacitor reformation system of claim 1 wherein the switching control module controls the duty cycle of the switching device to cure defects formed in the oxide of the electrolytic capacitor in response to an indication that the electrolytic capacitor has not received power for a period greater than the predetermined period.

3. The electrolytic capacitor reformation system of claim 1 further comprising a pump that includes the electric motor and that pumps fluid when driven by the electric motor.

4. The electrolytic capacitor reformation system of claim 1 wherein the switching control module selectively transitions the switching device to an open state in response to a determination that the curing of defects formed in the oxide of the electrolytic capacitor is complete.

5. The electrolytic capacitor reformation system of claim 4 wherein the switching control module determines that the curing of defects formed in the oxide of the electrolytic capacitor is complete when a difference between a voltage of the battery and a voltage of the electrolytic capacitor is less than a predetermined voltage.

6. The electrolytic capacitor reformation system of claim 4 further comprising a second switching device that is connected in a second current path between the battery and the electrolytic capacitor.

7. The electrolytic capacitor reformation system of claim 6 wherein the switching control module selectively transitions the second switching device to a closed state after transitioning the switching device to the open state.

8. The electrolytic capacitor reformation system of claim 7 wherein the switching control module begins switching switches of the motor driver module after transitioning the second switching device to the closed state.

9. An electrolytic capacitor reformation method for a vehicle, comprising:
receiving power from a battery of the vehicle using an electrolytic capacitor, wherein defects form in an oxide of the electrolytic capacitor when the electrolytic capacitor has not received power for at least a predetermined period;
receiving power from the electrolytic capacitor using a motor driver module;
driving an electric motor of the vehicle using the motor driver module;
varying a duty cycle of a switching device that is connected in series with a resistor in a current path between the battery and the electrolytic capacitor as a function of a leakage current through the electrolytic capacitor to cure defects formed in the oxide of the electrolytic capacitor,
wherein the resistor limits current flow through the current path;
determining an equivalent series resistance (ESR) of the electrolytic capacitor; and
initiating the curing of the defects formed in the oxide of the electrolytic capacitor in response to a determination that the ESR of the electrolytic capacitor is less than a predetermined resistance.

10. The electrolytic capacitor reformation method of claim 9 further comprising controlling the duty cycle of the switching device to cure defects formed in the oxide of the electrolytic capacitor in response to an indication that the electrolytic capacitor has not received power for a period greater than the predetermined period.

11. The electrolytic capacitor reformation method of claim 9 further comprising driving a fluid pump using the electric motor.

12. The electrolytic capacitor reformation method of claim 9 further comprising selectively transitioning the switching device to an open state in response to a determination that the curing of the defects formed in the oxide of the electrolytic capacitor is complete.

13. The electrolytic capacitor reformation method of claim 12 further comprising determining that the curing of the defects formed in the oxide of the electrolytic capacitor is complete when a difference between a voltage of the battery and a voltage of the electrolytic capacitor is less than a predetermined voltage.

14. The electrolytic capacitor reformation method of claim 12 further comprising selectively transitioning a second switching device that is connected in a second current path between the battery and the electrolytic capacitor to a closed state.

15. The electrolytic capacitor reformation method of claim 14 further comprising selectively transitioning the second switching device to the closed state after transitioning the switching device to the open state.

16. The electrolytic capacitor reformation method of claim 15 further comprising beginning switching switches of the motor driver module after transitioning the second switching device to the closed state.

17. The electrolytic capacitor reformation method of claim 9 wherein the predetermined period is at least 6 months.

18. The electrolytic capacitor reformation system of claim 1 wherein the predetermined period is at least 6 months.

Assignees

• Philippart Timothy P
• Gm Global Tech Operations Inc

Inventors

• Philippart Timothy P

Classifications

• B60L58/30

  for monitoring or controlling fuel cells · CPC title

• B60L2240/529

  Current · CPC title

• B60L2240/547

  Voltage · CPC title

• H02J7/345

  using capacitors as storage or buffering devices · CPC title

• B60K6/28 Primary

  characterised by the electric energy storing means, e.g. batteries or capacitors · CPC title