Zero power startup circuit for vibrational energy harvesting

• US 10,312,797 B1
• Filed: 08/29/2016
• Issued: 06/04/2019
• Est. Priority Date: 08/29/2016
• Status: Active Grant

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: The United States of America As Represented By The Secretary of Agriculture
• Inventors: Phipps, Alex G., Bozeman, Eric G.
• Primary Examiner(s): Barnie, Rexford N
• Assistant Examiner(s): Ortiz, Elim
• Application Number:
  US15/250,299
• Time in Patent Office: 1,009 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 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: H02M 1/0006 Arrangements for supplying an adequate voltage to the control circuit of converters
• CPC Class Codes: H02M 1/0032 Control circuits allowing low power mode operation, e.g. in standby mode
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 1/36 Means for starting or stopping converters
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• 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 energy harvesting system includes a transducer, a capacitor, a power converter, a power converter control line, a control switch and a control switch control line. The transducer harvests energy and outputs electrical current based on the harvested energy. The capacitor stores a rectified voltage based on the electrical current. The control switch can be open or closed. The control switch control line is arranged to provide a control voltage based on the rectified voltage to the control switch. When the control voltage is equal to or greater than a threshold voltage the control switch is closed such that the power converter control line electrically connects the power converter to a battery in order to provide harvested energy to the battery.

Claims

1. An energy harvesting system for preventing unwanted battery drain, said energy harvesting system comprising:

a transducer;

a capacitor;

a power converter;

a power converter control line;

a control switch, the control switch comprising one of;

a metal oxide semiconductor field effect transistor having a gate tied to rectified DC voltage from a rectifier and a source/drain, the source/drain configured to couple with a battery and the power converter; and

an electromechanical relay having a terminal tied to the rectified DC voltage from the rectifier and another terminal coupled with one of ground and a bipolar junction transistor; and

a control switch control line,

wherein said control switch control line is arranged to provide a control voltage, based on a rectified voltage, to said control switch,

wherein, when the control voltage is less than a predetermined threshold voltage, said control switch is operable in an open state,

wherein said power converter control line decouples from said power converter, and

wherein said power converter deactivates.

2. The system of claim 1, further comprising a rectifier disposed between said transducer and said capacitor.

3. The system of claim 2, wherein said transducer comprises at least one of a group consisting essentially of a piezoelectric transducer, an optoelectronic transducer, a magnetoelectric transducer, a bioelectric transducer, and a thermoelectric transducer.

4. The system of claim 3,

wherein said transducer comprises a piezoelectric transducer, and

wherein said rectifier comprises a full wave rectifier.

5. The system of claim 1, further comprising an impedance element disposed on said control switch control line.

6. The system of claim 5, further comprising an impedance control device coupled with at least one of a group consisting essentially of said capacitor and said impedance element.

7. The system of claim 6,

wherein said impedance element comprises an adjustable resistor, and

wherein said impedance control device is coupled with said adjustable resistor and is operable for adjusting resistance of said adjustable resistor to adjust the threshold voltage.

8. The system of claim 6,

wherein said capacitor comprises an adjustable capacitor, and

wherein said impedance control device is coupled with said adjustable capacitor and is operable for adjusting capacitance of said adjustable capacitor to adjust the threshold voltage.

9. The system of claim 6,

wherein said impedance element comprises an adjustable resistor,

wherein said capacitor comprises an adjustable capacitor, and

wherein said impedance control device is coupled with said adjustable resistor, is coupled with said adjustable capacitor, is operable for adjusting resistance of said adjustable resistor, and is operable for adjusting capacitance of said adjustable capacitor to adjust the threshold voltage.

10. An energy harvesting system for preventing unwanted battery drain, comprising:

a transducer operable to harvest energy and to output an electrical current based on the harvested energy;

a capacitor operable to store a rectified voltage based on the electrical current provided by the transducer;

a power converter;

a power converter control line;

a control switch operable to be in one of an open state and a closed state, the control switch comprising one of;

a metal oxide semiconductor field effect transistor having a gate tied to rectified DC voltage from a rectifier and a source/drain, the source/drain configured to couple with a battery and the power converter; and

an electromechanical relay having a terminal tied to the rectified DC voltage from the rectifier and another terminal coupled with one of ground and a bipolar junction transistor;

a battery; and

a control switch control line,

wherein said control switch control line is arranged to provide a control voltage, based on the rectified voltage, to said control switch,

wherein, when the control voltage is less than a threshold voltage, said control switch is in an open state, and

wherein said power converter control line decouples from said power converter.

11. The system of claim 10, further comprising a rectifier disposed between said transducer and said capacitor.

12. The system of claim 11, wherein said transducer comprises at least one of a group consisting essentially of a piezoelectric transducer, an optoelectronic transducer, a magnetoelectric transducer, a bioelectric transducer, and a thermoelectric transducer.

13. The system of claim 12,

wherein said transducer comprises a piezoelectric transducer, and

wherein said rectifier comprises a full wave rectifier.

14. The system of claim 10, further comprising an impedance element disposed on said control switch control line.

15. The system of claim 14, further comprising an impedance control device in connection with at least one of a group consisting essentially of said capacitor and said impedance element.

16. The system of claim 15,

wherein said impedance element comprises an adjustable resistor, and

wherein said impedance control device is coupled with said adjustable resistor and is operable for adjusting resistance of said adjustable resistor to adjust the threshold voltage.

17. The system of claim 15,

wherein said capacitor comprises an adjustable capacitor, and

wherein said impedance control device is coupled with said adjustable capacitor and is operable for adjusting capacitance of said adjustable capacitor to adjust the threshold voltage.

18. A method of using an energy harvesting system for preventing unwanted battery drain, the system comprising a transducer, a capacitor, a power converter, a power converter control line, a control switch operable in one of an open state and a closed state, a battery, and a control switch control line, said method comprising:

harvesting, via the transducer, energy, thereby providing harvested energy;

outputting, via the transducer, electrical current based on the harvested energy;

storing, via the capacitor, a rectified voltage based on the electrical current;

providing, via the control switch control line, a control voltage, based on the rectified voltage, to said control switch, providing the control switch comprising providing one of;

a metal oxide semiconductor field effect transistor having a gate tied to rectified DC voltage from a rectifier and a source/drain, the source/drain configured to couple with a battery and the power converter; and

an electromechanical relay having a terminal tied to the rectified DC voltage from the rectifier and another terminal coupled with one of ground and a bipolar junction transistor;

when the control voltage is less than a predetermined threshold voltage, placing the control switch in an open state, wherein the power converter control line decouples from the power converter, and wherein the power converter deactivates; and

when the control voltage is equal to or greater than then instantaneous threshold voltage, placing the control switch in a closed state, wherein the power converter control line couples with the power converter, wherein the power converter receives an operating signal from the battery, and wherein the power converter outputs converted energy, based on the control voltage, to the battery.