Vibrational energy harvester

• US 9,118,187 B1
• Filed: 03/14/2013
• Issued: 08/25/2015
• Est. Priority Date: 03/14/2013
• Status: Expired due to Fees

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Islam, Rashed Adnan
• Primary Examiner(s): Williams, Arun
• Application Number:
  US13/828,740
• Time in Patent Office: 894 Days
• Field of Search: 320/103
• US Class Current: 1/1
• CPC Class Codes: H02J 7/32 for charging batteries from a charging set comprising a non-electric prime mover rotating at constant speed
• CPC Class Codes: H02K 35/02 with moving magnets and stationary coil systems
• CPC Class Codes: H02N 2/186 Vibration harvesters
• CPC Class Codes: H10N 30/306 Cantilevers
• 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

Abstract

Some examples include an energy harvester for use in an electronic device to convert mechanical energy associated with vibrations of the electronic device into electrical energy. For instance, an energy harvester including rows of piezoelectric cantilevers may be arranged around a proof mass and may be utilized to convert the vibrations into electrical energy. In some examples, the energy harvester may include an electromagnetic energy harvester in addition to, or in place of the piezoelectric energy harvester.

Claims

1. A device comprising:

an energy harvester to convert vibrations of the device into electrical energy, the energy harvester including;

a proof mass having a compartment;

at least two piezoelectric cantilever transducers extending outward from the proof mass in opposite directions, the piezoelectric cantilever transducers supporting the proof mass to allow movement of the proof mass in response to the vibrations; and

a first magnet is partially contained within a first end of the compartment;

a second magnet is partially contained within a second end of the compartment, the second end opposite the first end;

a coil at least partially wound around at least a portion of the compartment; and

a third magnet suspended within the compartment between the first magnet and the second magnet by repulsive magnetic forces of the first magnet and the second magnet; and

a capacitor having a first end coupled to the coil and the piezoelectric cantilever transducers to collect the electrical energy generated by the energy harvester and store the electrical energy and a second end coupled to a battery.

2. The device as recited in claim 1, wherein:

the at least two piezoelectric cantilever transducers extending outward from the proof mass form a first symmetric pattern centered on the proof mass and are associated with a first row of piezoelectric cantilevers transducers; and

the energy harvester includes a second row of piezoelectric cantilevers transducers, the second row of piezoelectric cantilever transducers including at least two additional piezoelectric cantilever transducers extending outward from the proof mass to form a second symmetric pattern centered on the proof mass.

3. An energy harvester comprising:

a compartment within the energy harvester;

a first magnet is partially contained within a first end of the compartment;

a second magnet is partially contained within a second end of the compartment, the second end opposite the first end;

a coil at least partially wound around a portion of the compartment; and

a third magnet suspended within the compartment between the first magnet and the second magnet, the third magnet able to move within the coil to generate an electric current within the coil.

4. The energy harvester as recited in claim 3, wherein the compartment is disposed within a proof mass, further comprising a plurality of piezoelectric cantilever transducers grouped into symmetric pairs, each of the symmetric pairs having two piezoelectric cantilever transducers extending outward from the proof mass in opposite directions.

5. An energy harvester comprising:

a proof mass having a compartment and configured to move in response to vibrations of the energy harvester;

a magnet suspended within the compartment within a coil of wires and configured to oscillate within the coil to generate an electric current within the coil, in response to the vibrations of the energy harvester; and

a plurality of piezoelectric cantilever transducers to convert the movement of the proof mass into a charge, the plurality of piezoelectric cantilever transducers extending radially from the proof mass.

6. The energy harvester as recited in claim 5, wherein the plurality of piezoelectric cantilever transducers are grouped into pairs, each of the pairs having two piezoelectric cantilever transducers extending outward from the proof mass in opposite directions.

7. The energy harvester as recited in claim 5, wherein the plurality of piezoelectric cantilever transducers are included in a first row, further comprising a second row of piezoelectric cantilevers transducers, the second row of piezoelectric cantilever transducers extending radially from the proof mass.

8. The energy harvester as recited in claim 7, wherein:

first row of piezoelectric cantilever transducers is in a first symmetric pattern and the second row of piezoelectric cantilever transducers is in a second symmetric pattern; and

the first symmetric pattern is substantially the same as the second symmetric pattern.

9. The energy harvester as recited in claim 7, wherein:

first row of piezoelectric cantilever transducers is in a first symmetric pattern and the second row of piezoelectric cantilever transducers is in a second symmetric pattern; and

the first symmetric pattern varying from the second symmetric pattern.

10. The energy harvester as recited in claim 5, wherein the compartment further comprises:

a second magnet partially contained within a first end of the compartment; and

a third magnet partially contained within a second end of the compartment.

11. The energy harvester as recited in claim 5, wherein the first row of piezoelectric cantilever transducers are at least partially formed from lead zircontate titanate.

12. The energy harvester as recited in claim 5, wherein the first row of piezoelectric cantilever transducers are at least partially formed from a polycrystalline material.

13. The energy harvester as recited in claim 5, wherein the first row of piezoelectric cantilever transducers are at least partially formed from a single crystalline material.

14. The energy harvester as recited in claim 5, wherein the first row of piezoelectric cantilever transducers are tuned for a resonant frequency associated with the processor.

15. The energy harvester as recited in claim 5, wherein the first row of piezoelectric cantilever transducers are connected in parallel.

16. A device comprising:

a plurality of energy harvesters to convert vibrations into electrical energy, at least one the plurality of energy harvesters including;

a proof mass; and

at least a first row of piezoelectric cantilevers transducers, each row of piezoelectric cantilever transducers having symmetric pairs of piezoelectric cantilever transducers extending in opposite directions, the piezoelectric cantilever supporting the proof mass to allow movement of the proof mass in response to vibrations of the device.

17. The device as recited in claim 16, further comprising at least a second row of piezoelectric cantilever transducers arranged identically to the first row of piezoelectric cantilevers transducers.

18. The device as recited in claim 16, further comprising a capacitor having a cap coupled in series to the piezoelectric cantilever transducers to collect and store the electrical energy as a charge.

19. The device as recited in claim 18, wherein the capacitor has a second cap coupled to a battery and is configured to release the charge into the battery when a threshold is reached.

20. The device as recited in claim 16, further comprising a battery coupled to the plurality of energy harvesters, the battery to recharge based on the electrical energy generated by the plurality of energy harvesters.

21. The device as recited in claim 16, further comprising at least one component coupled to the plurality of energy harvesters, the at least one component to operate based on the electrical energy generated by the plurality of energy harvesters.

22. The device as recited in claim 16, wherein the proof mass has a compartment including:

a first magnet;

a second magnet;

a coil extending over at least a portion of the compartment; and

a third magnet suspended within the coil by magnetic forces of the first magnet and the second magnet, the third magnet to oscillate within the coil to generate an electric current within the coil in response to vibrations of the device.