FAST CHARGER FOR SUPER CAPACITOR

• US 20110121793A1
• Filed: 07/03/2009
• Published: 05/26/2011
• Est. Priority Date: 07/23/2008
• Status: Active Grant

• Current Assignee: Philips Lighting BV (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Liu, Chenyang
• Granted Patent: US 8,482,264 B2
• Time in Patent Office: Days
• US Class Current: 320/167
• CPC Class Codes: H01G 11/08 Structural combinations, e.g. assembly or connection, of hybrid or EDL capacitors with other electric components, at least one hybrid or EDL capacitor being the main component
• CPC Class Codes: H01G 9/28 Structural combinations of electrolytic capacitors, rectifiers, detectors, switching devices with other electric components not covered by this subclass
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: H02J 7/007184 in response to battery voltage gradient
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors

Abstract

This invention proposes a novel charging method for improving the efficiency of charging a super capacitor. The method comprises the steps of: charging the super capacitor with a first current; measuring a voltage of the super capacitor; stopping the supply of the first current when the measured voltage reaches a pre-defined voltage value; monitoring a voltage variation of the super capacitor; charging the super capacitor with a second current when the monitored voltage variation exceeds a pre-defined threshold within a pre-defined period. By using said two-phase charging, especially when using two different charging currents, it is easier to improve the charging efficiency without degrading the charging speed.

Claims

1. A method of charging a super capacitor, the method comprising the steps of:

a) charging the super capacitor with a first current;

b) measuring a voltage of the super capacitor;

c) stopping the supply of the first current when the measured voltage reaches a pre-defined voltage value;

d) monitoring a voltage variation of the super capacitor;

e) charging the super capacitor with a second current when the monitored voltage variation exceeds a pre-defined threshold within a pre-defined period.

2. A method as claimed in claim 1, further comprising the step of:

f) stopping the supply of the second current when the measured voltage reaches the pre-defined voltage value.

3. A method as claimed in claim 1, wherein the pre-defined period is in the range of 0.1 s˜

10 s.

4. A method as claimed in claim 3, wherein the pre-defined period is preferably 5 s.

5. A method as claimed in claim 1, wherein the ratio of the first current over the second current is in the range of 5 to 15.

6. A method as claimed in claim 5, wherein the ratio of the first current to the second current is preferably 10.

7. A method as claimed in claim 1, wherein the ratio of the pre-defined threshold to the pre-defined voltage value is in the range of 4%˜

20%, with a preferred value of 8%.

8. A method as claimed in claim 7, wherein the ratio of the pre-defined threshold to the pre-defined voltage value is preferably 8%.

9. A charger for charging a super capacitor, the charger comprising:

a first charging module (410), configured to charge the super capacitor (480) with a first current;

a second charging module (420), configured to charge the super capacitor with a second current;

a voltmeter (430), configured to measure a voltage of the super capacitor;

a processor (440), configured to compare a voltage variation of the super capacitor within a pre-defined period with a predefined voltage threshold, and to select one of the first charging module (410) and the second charging module (420) to charge the super capacitor.

10. A charger as claimed in claim 9, further comprising:

a multiplexer (450), configured to multiplex the interfaces of the first charging module and the second charging module, so as to provide a single interface to the super capacitor.

11. A charger for charging a super capacitor, the charger comprising:

a charging module (510), configured to adapt charging currents, depending on a received control signal, to charge the super capacitor (580);

a voltmeter (520), configured to measure a voltage of the super capacitor; and

a controller (530), configured to compare a voltage variation of the super capacitor within a pre-defined period with a pre-defined voltage threshold, and to output the control signal to control the charging module (510) selecting a corresponding charging current.