System For The Electronic Management Of Photovoltaic Cells With Adapted Thresholds

• US 20120256612A1
• Filed: 12/10/2010
• Published: 10/11/2012
• Est. Priority Date: 12/11/2009
• Status: Active Grant

• Current Assignee: Centre National De La Recherche Scientifique
• Original Assignee: Centre National De La Recherche Scientifique
• Inventors: Alonso, Corinne, Estibals, Bruno, Vermeersch, Marc, Berasategi, Alona, Cabal, Cédric, Petibon, Stéphane
• Granted Patent: US 9,515,517 B2
• Time in Patent Office: Days
• US Class Current: 323/311
• CPC Class Codes: H01L 31/02021 for solar cells electrical connection means, e.g. junction boxes, specially adapted for structural association with photovoltaic modules H02S40/34
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: H02M 1/0032 Control circuits allowing low power mode operation, e.g. in standby mode
• CPC Class Codes: H02M 1/0054 Transistor switching losses periodically suspending operation of switching converter in low power mode H02M1/0035
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel
• 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
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

The invention relates to a system for the electronic management of a photovoltaic generator, said system comprising a plurality of n static converters (11, 12, 13) connected in parallel, each converter (11, 12, 13) being electrically connected to at least one photovoltaic cell (10) of the generator. The number of converters connected is determined by comparing the generated power to thresholds P1, P2, . . . , Pn-1 which are defined as the power values substantially at the point of intersection of the performance curves for an increasing number of converters. The invention also relates to a generator comprising said system and to the associated control method.

Claims

1-22. -22. (canceled)

23. An electronic control system of a photovoltaic generator having a plurality of photovoltaic cells, the electronic control system comprising:

a plurality of converters coupled in parallel, each of said plurality of converters being electrically selectively coupled to at least one photovoltaic cell of the photovoltaic generator wherein the number of converters coupled to the photovoltaic generator cells is determined by comparing thresholds generated in power (PI, P2, . . . Pn-1) and wherein the thresholds are defined as power values substantially at a point of intersection of a yield curve for an increasing number of converters.

24. The system according to claim 23, wherein said plurality of converters is three converters.

25. The system according to claim 24, wherein a first threshold is less than ⅓

, preferably between 20 and 33%, advantageously between 23 and 32%.

26. The system according to claim 25, wherein a second threshold is less than 2/3, preferably between 35 and 55%, advantageously between 40 and 50%.

27. The system according to claim 23 wherein the threshold values depend upon an optimal voltage value V_opt of said at least one photovoltaic cell.

28. The system according to one of claim 23 wherein the threshold values are a function of an input voltage provided to said plurality of converters and wherein the input voltage is the optimal voltage value V_opt of said at least one photovoltaic cell.

29. The system according to claim 23 wherein the threshold values are selected based upon the period of the year and/or sunlight.

30. The system according to claim 23 wherein the threshold values are selected based upon a duty cycle of the converters.

31. The system according claim 23 wherein the threshold values are selected based upon a temperature of the converters.

32. The system according to claim 23 wherein the threshold values are selected based upon an age of the converters.

33. The system according to claim 23 further comprising a memory management system and wherein the threshold values are stored in said memory management system and wherein the threshold values are subject to change depending upon the measurement of a parameter the photovoltaic generator.

34. The system according claim 23 further comprising a device for determining the yield curve in function of the power.

35. The system according to claim 23 wherein said plurality of converters are connected in turn.

36. The system according to claim 35 wherein the rotation of said plurality of converters is the variation in the number of converters engaged.

37. The system according to claim 35 wherein the rotation of said plurality of converters depends upon the state of the components of said plurality of converters.

38. A photovoltaic generator comprising:

at least one photovoltaic cell; and

a management system having threshold values stored therein and wherein the threshold values are subject to change depending upon a measurement of a parameter the photovoltaic generator.

39. A method of controlling a photovoltaic generator having at least one photovoltaic cell and a plurality of n parallel coupled converters, each of the plurality of converters being electrically coupled to at least one of the at least one photovoltaic cells, the method comprising:

determining power generated by the at least one photovoltaic cell;

comparing power generated by the at least one photovoltaic cell with peak power;

comparing power generated by the at least one photovoltaic cell with one or more threshold values wherein the thresholds values are defined as power values substantially at a point of intersection of one or more yield curves for an increasing number of converters of at least one photovoltaic cell; and

coupling i converters when a measured power value is between Pi and Pi-1 or all the converters if the measured power value is greater than Pn-1.

40. The method of claim 39 further comprising, in response to a measured power value, connecting additional converters when all converters are not connected.

41. The method of claim 40, comprising:

connecting at least a first one of the plurality of n parallel coupled converters to at least one of the at least one photovoltaic cells; and

connecting a larger number of the plurality of n parallel coupled converters to at least one of the at least one photovoltaic cells; and

in response to a need to reduce the number of the plurality of n parallel coupled converters to at least one of the at least one photovoltaic cells, disconnecting the first one of the plurality of n parallel coupled converters.

42. The method of claim 41 further comprising rotating the plurality of n parallel coupled converters in response to a change in measured power value in thresholds between Pi and Pi-1

43. The method of claim 42 further comprising:

determining one or more of;

a duration of use and/or a number of use of each of the plurality of n parallel coupled converters;

connecting each of the plurality of n parallel coupled converters such that over time, one or more of duration of use and/or the number of use is substantially equal amongst the plurality of n parallel coupled converters.

44. The method of claim 43 for controlling a photovoltaic generator comprising at least one photovoltaic cell;

and a management system having threshold values stored therein and wherein the threshold values are subject to change depending upon a measurement of a parameter.