METHOD AND APPARATUS FOR MULTI-PHASE POWER TRANSFER

• US 20130021006A1
• Filed: 07/18/2011
• Published: 01/24/2013
• Est. Priority Date: 07/18/2011
• Status: Active Grant

• Current Assignee: Enphase Energy Incorporated
• Original Assignee: Enphase Energy Incorporated
• Inventors: FORNAGE, MARTIN
• Granted Patent: US 9,774,189 B2
• Time in Patent Office: Days
• US Class Current: 323/234
• CPC Class Codes: H02J 2300/26 involving maximum power point tracking control for photovoltaic sources
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/48 Controlling the sharing of the in-phase component
• 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 7/48 using discharge tubes with control electrode or semiconductor devices with control electrode
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y02E 70/30 Systems combining energy storage with energy generation of non-fossil origin

Abstract

A method and apparatus for power conversion. In one embodiment, an apparatus comprises a power conversion module for converting a first current to a second current, wherein the first current or the second current is an AC current having at least two phases; and a waveform modification module, coupled to the power conversion module, for modifying the AC current to generate a modified AC current, wherein each phase of the modified AC current has a value of zero at the beginning of an AC line cycle.

Claims

1. An apparatus for power conversion, comprising:

a power conversion module for converting a first current to a second current, wherein the first current or the second current is an AC current having at least two phases; and

a waveform modification module, coupled to the power conversion module, for modifying the AC current to generate a modified AC current, wherein each phase of the modified AC current has a value of zero at the beginning of an AC line cycle.

2. The apparatus of claim 1, wherein the waveform modification module multiplies the AC current by a modification waveform to generate the modified AC current.

3. The apparatus of claim 2, wherein the modification waveform is symmetric across at least one AC line cycle.

4. The apparatus of claim 3, wherein the modification waveform increases from zero to a stable value during an attack period, remains at the stable value during a stable period, and decays from the stable value to zero during a decay period.

5. The apparatus of claim 4, wherein the attack period spans a first third of the at least one AC line cycle, the stable period spans a second third of the at least one AC line cycle, and the decay period spans a third third of the at least one AC line cycle.

6. The apparatus of claim 1, wherein the modified AC current is synchronized to a master phase and the master phase corresponds to the AC line cycle.

7. The apparatus of claim 6, wherein the master phase is determined based on a unique identification number of an inverter comprising the power conversion module.

8. The apparatus of claim 1, wherein each phase of the modified AC current has a slope of zero at the beginning of the AC line cycle.

9. A method for power conversion, comprising:

converting a first current to a second current, wherein the first current or the second current is an AC current having at least two phases; and

modifying the AC current to generate a modified AC current, wherein each phase of the modified AC current has a value of zero at the beginning of an AC line cycle.

10. The method of claim 9, wherein modifying the AC current comprises multiplying the AC current by a modification waveform.

11. The method of claim 10, wherein the modification waveform is symmetric across at least one AC line cycle.

12. The method of claim 11, wherein the modification waveform increases from zero to a stable value during an attack period, remains at the stable value during a stable period, and decays from the stable value to zero during a decay period.

13. The method of claim 12, wherein the attack period spans a first third of the at least one AC line cycle, the stable period spans a second third of the at least one AC line cycle, and the decay period spans a third third of the at least one AC line cycle.

14. The method of claim 9, wherein the AC line cycle corresponds to a master phase and the modified AC current is synchronized to the master phase.

15. The method of claim 14, further comprising determining the master phase based on a unique identification number of an inverter that converts the first current to the second current.

16. The method of claim 9, wherein each phase of the modified AC current has a slope of zero at the beginning of the AC line cycle.

17. A system for power conversion, comprising:

a plurality of power conversion modules, wherein each power conversion module of the plurality of power conversion modules converts a first current to a second current, wherein the first current or the second current is an AC current having at least two phases; and

a plurality of waveform modification modules coupled to the plurality of power conversion modules in a one-to-one correspondence, wherein each waveform modification module modifies the AC current to generate a modified AC current, wherein each phase of the modified AC current has a value of zero at the beginning of an AC line cycle.

18. The system of claim 17, wherein (i) each modified AC current corresponding to a first subset of the power conversion modules is synchronized to a first master phase, (ii) each modified AC current corresponding to a second subset of the plurality of power conversion modules is synchronized to a second master phase, and (iii) each modified AC current corresponding to a third subset of the plurality of power conversion modules is synchronized to a third master phase.

19. The system of claim 18, wherein assignment of the first, the second, and the third master phase among the plurality of power conversion modules is randomly distributed.

20. The system of claim 18, wherein each waveform modification module multiplies the AC current by a modification waveform to generate the modified AC current.