EFFICIENT SUPERCAPACITOR CHARGING TECHNIQUE BY A HYSTERETIC CHARGING SCHEME

• US 20170117730A1
• Filed: 06/24/2016
• Published: 04/27/2017
• Est. Priority Date: 06/26/2015
• Status: Abandoned Application

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: KIM, Sehwan, CHOU, Pai H.
• Application Number:
  US15/192,430
• Publication Number:
  US 20170117730A1
• Time in Patent Office: Days
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: H02M 1/0035 using burst mode control
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• 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: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

An efficient supercapacitor charging scheme with low ambient energy sources is provided. In one embodiment, a charging apparatus is disclosed. The apparatus includes a burst control module, and a boost converter configured to control a two-stage supercapacitor composition. The boost converter may be a pulse-frequency modulation (PFM) dc-dc boost converter and the apparatus may include a charge-strapping supercapacitor to control efficiency and the amount of burst charging time. Another embodiment is directed to a hysteretic charging scheme including controlling hysteresis, optimizing window size, and controlling a two-stage supercapacitor composition with a pulse-frequency modulation (PFM) dc-dc boost converter. The charging scheme is useful to extend the upper bound on the capacitance of supercapacitors.

Claims

1. A supercapacitor charger comprising:

a charge-strapping supercapacitor configured to accumulate energy from a low-power source;

a burst control module configured to release energy accumulated by the charge-strapping supercapacitor, wherein a burst transfer window for releasing energy by the burst control module is controlled by the charge-strapping capacitor; and

a boost converter configured to charge a reservoir supercapacitor, wherein the boost converter is enabled and disabled by the burst control module based on the burst transfer window.

2. The supercapacitor charger of claim 1, wherein the charge-strapping supercapacitor is between the range of 2 F to 5 F.

3. The supercapacitor charger of claim 1, wherein the charge-strapping supercapacitor includes a charge time based on a leakage current of the reservoir supercapacitor.

4. The supercapacitor charger of claim 1, wherein the burst control module includes a non-inverting comparator configured to provide burst-transfer window control.

5. The supercapacitor charger of claim 1, wherein the burst control module enables the boost converter based on the charge-strapping supercapacitor approaching an upper bound of the burst transfer window and wherein the burst control module disables the boost converter when the voltage of the charge-strapping supercapacitor drops to a lower bound of the burst transfer window.

6. The supercapacitor charger of claim 1, wherein the burst control module turns the boost control on to charge the reservoir supercapacitor at the maximum power point of the low power source.

7. The supercapacitor charger of claim 1, wherein the boost converter is a pulse-frequency modulation (PFM) dc-dc boost converter.

8. The supercapacitor charger of claim 1, wherein the boost converter transfers stored energy of the charge-strapping supercapacitor to the reservoir supercapacitor during the burst transfer window.

9. The supercapacitor charger of claim 1, wherein the burst transfer window is an adjustable burst window.

10. The supercapacitor charger of claim 1, wherein the charge-strapping supercapacitor is arranged in parallel with the boost converter and the reservoir supercapacitor, and wherein the burst controller controls connection of the charge-strapping supercapacitor to the boost converter.

11. The supercapacitor charger of claim 1, wherein the low power source is at least one of a thermoelectric generator, fuel cell, galvanic corrosion source, and photovoltaic cell.

12. A supercapacitor charger comprising:

a charge-strapping supercapacitor configured to accumulate energy from a low-power source, wherein the charge-strapping supercapacitor includes a charge time based on a leakage current of the reservoir supercapacitor;

a burst control module configured to release energy accumulated by the charge-strapping supercapacitor, wherein a burst transfer window for releasing energy by the burst control module is controlled by the charge-strapping capacitor burst control module enables the boost converter based on the charge-strapping supercapacitor approaching an upper bound of the burst transfer window and wherein the burst control module disables the boost converter when the voltage of the charge-strapping supercapacitor drops to a lower bound of the burst transfer window; and

a boost converter configured to charge a reservoir supercapacitor, wherein the boost converter is a pulse-frequency modulation (PFM) dc-dc boost converter, and wherein the boost converter is enabled and disabled by the burst control module based on the burst transfer window.

13. The supercapacitor charger of claim 12, wherein the charge-strapping supercapacitor is between the range of 2 F to 5 F.

14. The supercapacitor charger of claim 12, wherein the burst control module includes a non-inverting comparator configured to provide burst-transfer window control.

15. The supercapacitor charger of claim 12, wherein the burst control module turns the boost control on to charge the reservoir supercapacitor at the maximum power point of the low power source.

16. The supercapacitor charger of claim 12, wherein the boost converter transfers stored energy of the charge-strapping supercapacitor to the reservoir supercapacitor during the burst transfer window.

17. The supercapacitor charger of claim 12, wherein the burst transfer window is an adjustable burst window.

18. The supercapacitor charger of claim 12, wherein the charge-strapping supercapacitor is arranged in parallel with the boost converter and the reservoir supercapacitor, and wherein the burst controller controls connection of the charge-strapping supercapacitor to the boost converter.

19. The supercapacitor charger of claim 12, wherein the low power source is at least one of a thermoelectric generator, fuel cell, galvanic corrosion source, and photovoltaic cell.

20. A method of implementing a hysteretic charging scheme comprising:

controlling hysteresis;

optimizing a window size; and

controlling a two-stage supercapacitor composition with a pulse-frequency modulation dc-dc boost converter.