Power extractor for impedance matching

• US 7,960,870 B2
• Filed: 07/07/2007
• Issued: 06/14/2011
• Est. Priority Date: 11/27/2006
• Status: Active Grant

• Current Assignee: Apparent Labs LLC
• Original Assignee: Xslent Energy Technologies, LLC
• Inventors: Besser, David A., Matan, Stefan
• Primary Examiner(s): Fureman; Jared J
• Assistant Examiner(s): Amrany; Adi
• Application Number:
  US11/774,565
• Publication Number:
  US 20080122449A1
• Time in Patent Office: 1,438 Days
• Field of Search: 307/151
• US Class Current: 307/151
• CPC Class Codes: G05F 1/67 to the maximum power available from a generator, e.g. from solar cell
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

In some embodiments, a power extractor may operate such that the source impedance and the load impedance may have various values. The power extractor dynamically matches the impedance of the source and the load for the maximum transfer of power. The power extractor includes detection circuitry to continuously detect power changes, and is operated such that impedances of the power extractor between the source and load are dynamically changed in response to the detected power changes. The power extractor may then match an impedance of a power source to the impedance of a load. Other embodiments are described and claimed.

Claims

1. An apparatus comprising:

a first node to connect to a power source;

a second node to connect to a variable load; and

a power extractor to transfer power from the first node to the second node, wherein the power extractor includes detection circuitry to detect power changes at the first node, and

wherein the power extractor is to be operated such that impedances of the power extractor are dynamically changed both in response to the detected power changes at the source and a capacity of the load to receive power generated by the power source,

an output impedance of the power extractor as seen from the second node to be dynamically changed when the load cannot receive all power generated by the power source, to approach matching a first impedance as seen looking into the power extractor from the second node, the first impedance including an impedance of the power extractor and the power source coupled to the first node;

an input impedance of the power extractor as seen from the first node to be dynamically changed when the load can receive more power than generated by the power source, to approach matching a second impedance as seen looking into the power extractor from the first node, the second impedance including an impedance of the power extractor and the load coupled to the second node; and

both output and input impedances to be dynamically changed when the load can receive all power generated by the power source.

2. The apparatus of claim 1, wherein the power extractor is to be operated such that an the output impedance of the power extractor is dynamically changed in response to the continuously detected power changes so that under some load conditions the output impedance of the power extractor as seen from the second node approaches matching an impedance of the load connected to the second node.

3. The apparatus of claim 1, wherein in practice the input impedance as seen from the first node typically does not precisely match with the impedance of the power source, and the output impedance as seen from the second node typically does not precisely match the impedance of the load, but the dynamic changes lead toward close matching of the impedances.

4. The apparatus of claim 1, wherein when the power changes are zero and the power is at a power maximum of a knee of a power curve of the power source, the input impedance as seen from the first node and the first impedances are essentially matched resulting in the power source providing a maximum power available from the power source, given environmental conditions in which the power source operates.

5. The apparatus of claim 1, wherein the power extractor includes circuitry to prevent the power from staying at a local power maximum caused by a noise peak in a power curve of the power source at which the power extractor detects a zero power change local to the noise peak, which is different from a power maximum of a knee of the power curve of the power source.

6. The apparatus of claim 1, wherein the power extractors at times operates in a protection mode in which an impedance of the power extractor is dynamically changed in response to detected power changes to not match an impedance as seen looking into the power extractor.

7. The apparatus of claim 1, wherein the detected power changes include a continuously detected instantaneous power slope.

8. The apparatus of claim 1, wherein the power extractor includes a first energy transfer circuit connected to the first node to continuously transfer energy, a second energy transfer circuit connected to the second node to continuously transfer energy, and an intermediate energy transfer circuit connected between the first and second energy transfer circuits to discontinuously transfer energy between the first and second energy transfer circuits.

9. The apparatus of claim 8, wherein the first energy transfer circuit matches the input impedance of the power extractor as seen from the first node with the second impedance.

10. The apparatus of claim 8, wherein the second energy transfer circuit matches an output impedance of the power extractor as seen from the second node with a first impedance including a the load connected to the second node.

11. The apparatus of claim 8, wherein the power extractor includes switching circuitry to modulate voltages at a third node between the first and intermediate energy transfer circuits, and at a fourth node between the intermediate and second energy transfer circuits.

12. The apparatus of claim 1, wherein the power extractor includes switching circuitry with a duty cycle that is at least partially dependent on the detected power changes, a voltage level of the second node, and an amount of current the second node is capable of drawing at the voltage level, and a magnitude of the transferred power is at least partially dependent on the duty cycle.

13. The apparatus of claim 12, wherein a frequency of the switching circuits controls efficiency of power transfer and an amount of power transferred, to the second node.

14. An apparatus comprising:

an input port to connect to a power source;

an output port to connect to a variable load; and

power transfer circuitry to transfer power from the input to the output port and detect power changes in the power source and the load, dynamically changing output and input impedances in response to detected power changes in both the power source and the load;

power change detection circuitry to continuously detect power changes at the input port, and wherein the apparatus is operated so as to seek having an output impedance of the power transfer circuitry as seen looking into the output port match a first impedance outside the power transfer circuitry, wherein the first impedance includes an impedance of the load, and

power change detection circuitry to continuously detect power changes at the output port, and wherein the apparatus is operated so as to seek haying an input impedance of the power transfer circuitry as seen looking into the input port match a second impedance outside the power transfer circuitry, wherein the second impedance includes an impedance of the power source.

15. The apparatus of claim 14, wherein the output impedance of the power transfer circuitry as seen looking into the output port equals the combined impedance of the power transfer circuitry and power source connected to the input port.

16. The apparatus of claim 15, wherein the power source and the power load are separate from the apparatus.

17. The apparatus of claim 15, wherein the power source and the power load are part of the apparatus.

18. The apparatus of claim 14, wherein the power source is part of the apparatus.

19. The apparatus of claim 14, wherein in practice the output impedance typically does not precisely match with the first impedance.

20. The apparatus of claim 14, wherein the power transfer circuitry is operated to transfer power at a magnitude to cause the power source to approach providing a maximum power available from the power source, given environmental conditions in which the power source operates.

21. The apparatus of claim 14, wherein the power transfer circuitry includes a first energy transfer circuit connected to the input port to continuously transfer energy, a second energy transfer circuit connected to the output port to continuously transfer energy, and an intermediate energy transfer circuit connected between the first and second energy transfer circuits to discontinuously transfer energy between the first and second energy transfer circuits.

22. A system comprising:

a power source coupled to a first node; and

a second node to couple to a variable load; and

a power extractor to transfer power from the first node to the second node, wherein the power extractor includes detection circuitry to detect power changes at the first node, and

wherein the power extractor is to be operated such that impedances of the power extractor are dynamically changed both in response to the detected power changes at the source and a capacity of the load to receive power generated by the power source,

an output impedance as seen from the second node to be dynamically changed when the load cannot receive all power generated by the power source, to approach matching a first impedance as seen from the second node, the first impedance including an impedance of the power source;

an output impedance of the power extractor as seen from the second node to be dynamically changed when the load cannot receive all power generated by the power source, to approach matching a first impedance as seen looking into the power extractor from the second node, the first impedance including an impedance of the power source;

an input impedance of the power extractor as seen from the first node to be dynamically changed when the load can receive more power than generated by the power source, to approach matching a second impedance as seen looking into the power extractor from the first node, the second impedance including an impedance of the power extractor and the load coupled to the second node; and

both output and input impedances to be dynamically changed when the load can receive all power generated by the power source.

23. The system of claim 22, wherein in practice the input impedance as seen from the first node typically does not precisely match with the impedance of the power source, and the output impedance as seen from the second node typically does not precisely match the impedance of the load, but the dynamic changes lead toward very close matching of the impedances.