WO2012032274A1

WO2012032274A1 - Photovoltaic panel operation control

Info

Publication number: WO2012032274A1
Application number: PCT/FR2011/052064
Authority: WO
Inventors: Philippe Calzi; Bertrand Bertrand
Original assignee: Nexcis
Priority date: 2010-09-10
Filing date: 2011-09-08
Publication date: 2012-03-15
Also published as: FR2964759B1; FR2964759A1

Abstract

The invention relates to photovoltaic panel operation control for panels of the type designed to operate with at least one nominal operating point corresponding to a maximum power produced by the panel. The panel is connected, in particular, to a control module for controlling the operation of the panel using at least: a nominal operating mode at maximum power, or a panel degraded operating mode. According to the invention, degraded operation corresponds to the production by the panel of power at a non-zero value below the aforesaid maximum power. Consequently, during the maintenance of the panel, or in the event of the theft thereof, a minimum power can be discharged without creating a fire hazard.

Description

Control of the operation of a photovoltaic panel

The present invention relates to an operation control of at least one photovoltaic panel, in particular the electrical power produced by the panel.

With reference to FIG. 1 representing the power produced by the panel (dotted line curve), here as a function of the voltage V across the electrode terminals of the panel, a peak of maximum power PM corresponding to the normal operating regime generally appears. of the panel.

In some cases, it may be desired to lower this power, especially when a maintenance of a particular panel in a panel park must intervene, or in case of theft of the panel by a malicious third party. In such cases, a control of the operation of the photovoltaic panel usually switches the power produced by this panel from the maximum value PM to the value zero. It follows, in fact, that the panel is short-circuited (application of a zero voltage across the panel), while a strong current which, for example, originates from a feedback of currents from other panels mounted in parallel, can still circulate in the panel. This situation is likely to damage the panel, even to burn it, creating a fire.

The present invention then improves the situation. It proposes for this purpose a method of controlling the operation of at least one photovoltaic panel. As described above with reference to Figure 1, this panel is arranged to operate according to at least one nominal operating point corresponding to a maximum power produced by the panel. The panel is connected to a control module to control the operation of the panel. In particular, the control module is arranged to control the operation of the panel according to at least:

- the aforementioned nominal operation, at maximum power, or - according to a degraded operation of the panel (especially in case of theft or for maintenance situations.

For the purposes of the invention, the degraded operation corresponds to a power output lower than the aforementioned maximum power, but not zero. In particular, this power in the degraded operating mode is intermediate between the maximum power and the zero power.

In a particular embodiment, the control module controls the operation of the panel in voltage. Thus, in the degraded operating mode, the voltage applied to the panel is intermediate between a zero voltage and a voltage corresponding to the aforementioned maximum power.

Of course, other variants are allowed, including a current control.

In an advantageous embodiment, the control module is:

- integrated into the panel and

connected to an internal connection layer of the panel (such as, for example, an internal connection strip to the panel structure), on the one hand, and to one or more connection cables to a distribution network, on the other hand .

Thus, the control module can be arranged to detect (especially in case of theft of the panel) a connection cable cutoff distribution network. In particular, the control module preferably comprises means for detecting a connection cable cut-off to the distribution network, and, if necessary, the control module is arranged to control the degraded operation.

In one embodiment, the control module comprises a regulator (for example a voltage across the panel) and means for driving this regulator (for example a microcontroller or other). In addition or as a variant of an embodiment in which the module comprises means for detecting a cable break, the control module can also be arranged for:

detect a modification in a signal reception from a control center

- and, if necessary, trigger the degraded operation of the panel.

This signal may be, for example, a radio frequency signal which the panel or its control module receives repeatedly, and if this signal is no longer received or if it is received with a different intensity or if another signal is received, the control module triggers the degraded operating mode. In an exemplary embodiment, the signal may comprise an encrypted identifier of the photovoltaic panel and as long as the control module recognizes this identifier, the normal operation of the panel continues. The degraded mode is activated on the other hand in case of detection of non-recognition of this identifier.

It is also possible to use triangulation means on the intensity of the signals received from different control centers. For example, the control module may include radiofrequency means for detecting position changes (in particular following an unexpected movement of the panel, for example in case of theft by a malicious third party). Again, the control module is advantageously arranged to control the degraded operation in case of detection of such a change of position of the panel. Thus, a control command of a functioning of the panel in advantageously degraded mode is emitted, in any case of theft detection of the panel. However, the degraded mode corresponds for example to a non-zero voltage application (but insufficient to reach the maximum power), so that the stolen panel is not necessarily then short-circuited and does not risk to harm the security of the site.

Similarly, the invention makes possible selective intervention on a particular panel, especially for a maintenance reason for example, since the The voltage of this panel is not reduced to zero and this panel is not short-circuited (with the risks associated with such a situation).

Nevertheless, in the case of a theft of the panel and its consequent operation in degraded mode with a non-zero power, fraudulent use of a panel operating thus remains possible, even at reduced power.

It is then advantageously proposed an embodiment in which, in this degraded operating mode, the control module delivers a succession of operating instructions of the panel at different powers, but all intermediate between said maximum power and zero power.

In addition, this succession is preferentially random in time, and, in addition or alternatively, these intermediate operating powers are preferably chosen randomly.

Thus, under these conditions, the power behavior of the panel can not be anticipated by a malicious user. The panel can not be used properly, especially interconnected with other panels or a downstream transformer.

In such an embodiment, the control module may advantageously comprise a generator of pseudo-random sequences. In addition, access to this generator can be protected. The possible means for accessing and understanding such sequences are then so expensive and / or tedious that a malicious third party is finally dissuaded from using the panel.

Moreover, in an embodiment according to which the control module is implanted in the panel and its connections are welded to an internal sheet of the panel, tearing off the control module would damage the connection layer and, in fact, the panel itself, thus preventing fraudulent reuse. The present invention also aims at a module for controlling the operation of at least one photovoltaic panel, comprising:

means for controlling the panel to operate according to at least one nominal operating point corresponding to a maximum power produced by the panel, and

means for receiving an interruption setpoint of said nominal operation for controlling a degraded operation of the panel.

For the purposes of the invention, the degraded operation corresponds to an intermediate power output between the maximum power and zero power.

Of course, the control module may furthermore comprise means for implementing the above method, for example the above-mentioned regulator, the means for driving the regulator, the generator of pseudo-random sequences, interconnections with a layer of internal connection of the panel, on the one hand, and with other panels or the distribution network, on the other hand, or others.

The present invention also relates to a photovoltaic panel comprising such a control module. In addition, this module can advantageously be integrated into the panel.

The present invention also relates to a computer program comprising instructions for the implementation of the above method, when the program is executed by a processor, in particular a control module within the meaning of the invention.

Other characteristics and advantages of the invention will appear on examining the detailed description below and the attached drawings in which:

FIG. 1 represents the variation of the power produced by a photovoltaic panel as a function of the voltage V (dotted line curve), as well as the variation of the current I as a function of the voltage V (solid line curve),

FIG. 2 illustrates a photovoltaic panel within the meaning of the invention, FIG. 3 illustrates a control module in the sense of the invention, as a detail of FIG. 2, in an exemplary embodiment in which the control module is integrated in the panel,

FIG. 4 is a general flowchart illustrating an exemplary algorithm of a computer program within the meaning of the invention,

FIG. 5 illustrates the random variations of power produced by the panel in degraded operating mode.

With reference to FIG. 1, the current variation characteristic I produced by the panel as a function of the voltage V (constant up to a given voltage) implies a variation in power P produced as a function of the voltage V having a maximum of PM power at the aforementioned voltage. Usually, the voltage V is chosen so that the panel produces this maximum power PM (for example using a voltage regulator, as shown in Figure 3 described below with reference to an exemplary embodiment). Nevertheless, within the meaning of the invention, the regulator is controlled to produce a lower power, under the conditions described below, without this power P being zero.

Referring now to FIG. 2, a PV photovoltaic panel comprises NC connection layers (for example photovoltaic modules between them in a panel). In particular, a terminating terminal ply connects the outside panel EXT (eg to a distribution network or other photovoltaic panels) via connection cables C1, C2. The control module in the sense of the invention is connected, on the one hand, to the abovementioned NC terminal connection ply and, on the other hand, to the cables C1, C2. In particular, the COM module has terminals B1, B2 (Figure 3) welded to the NC connection sheet, so that its uprooting of the panel by a malicious person causes degradation of the sheet and, from there, that of the panel. Furthermore, the COM module is integrated in the panel and fixed in the thickness of the panel, for example by gluing, so that tearing the COM module to the panel causes a local break of the panel resulting in sealing defects which can drastically reduce the operating capabilities of the panel, or even completely interrupt its operation.

For example, the control module COM can take the form of an integrated circuit molded on the output of the photovoltaic panel.

In addition, the control module COM comprises means for detecting a cut of at least one of the cables 01, 02 (arrow F of FIG. 3), causing a degraded operation of the panel, as will be seen later. .

With reference to FIG. 3, the module COM comprises for this purpose PCM means (for example a microcontroller or the like) for controlling a regulator REG in voltage of the panel. More particularly, the control module COM comprises, in the example shown, a voltage regulator REG whose terminals B1, B2 are connected to the terminal connection layer NC, on the one hand, and to the connection cables C1, 02 to the EXT distribution network (possibly via other photovoltaic panels). The regulator REG is controlled, in an exemplary embodiment, by a microcontroller MIC, capable of delivering to the regulator a voltage setpoint V:

- corresponding to the maximum power PM (FIG. 1), in the event of normal operation of the panel, or

- at an intermediate power between the null power and the maximum power PM, in case of detection of an abnormal situation or maintenance. For example, in the case of maintenance, a manual intervention on the control module can trigger a degraded operating mode in which the panel delivers a non-zero intermediate power. Thus, the panel is not short-circuited, which makes it possible to have to apply the degraded operating mode only to the panel on which maintenance must take place. Such an embodiment is particularly advantageous when this panel is connected in series with other panels. The control module COM furthermore comprises, in the example shown, a location-based means LOC, for example by triangulation on radio-frequency signals exchanged with several control stations of the panels among one or more parks. Thus, abnormal situations that the control module can detect are for example:

a displacement of the panel (in which case the locating means LOC no longer receives a signal from a usual station, or no longer receives this signal with the same intensity, and communicates this data to the microcontroller MIC to control a regulation according to the degraded mode),

a break in one of the cables C1, C2 (in which case the microcontroller receives this information (arrow F) and triggers the degraded mode),

- or others.

Thus, while a known solution to photovoltaic panel theft problems is the use of specific "screws" to fix them on their chassis, or the establishment of conventional security services (security companies, CCTV or other), the present invention advantageously proposes an electronic solution embedded in a photovoltaic panel.

Indeed, in case of theft of photovoltaic panels, the time of intervention of the security companies can be quite long and the stolen panels can then be used in any other installation. The present invention advantageously makes it possible to modify the electrical parameters of a photovoltaic panel in order to degrade its performance. Preferably, this degradation is random, as described in detail hereinafter with reference to FIG. 5, in particular in case of non-recognition of the panel in an installation (for example in case of theft).

More particularly, the invention makes it possible to deter theft of a photovoltaic panel by blocking its use, without presenting a particular danger of starting fire, electric shock, or irreversible deactivation of the panel while this deactivation would have been applied by mistake. In addition, as also described hereinafter, the invention also makes it possible to reconfigure the photovoltaic module to return to optimal operation in the event of recovery of the panel. In one embodiment, the degraded operation of the panel is oscillatory and random. The microcontroller MIC can contain at least one register for randomly controlling (according to a computer routine programmed in this sense) the operation of the regulation circuit REG so as to modify the operating point (in voltage and possibly in current, therefore in power output ) of the photovoltaic panel to make it unusable in another installation. The control module also allows the identification of the photovoltaic panel (for example by communication with a control center) in an installation of origin, which thus guarantees its proper functioning. If the communication / connection is interrupted between the panel and the control center, as soon as the panel is reconnected to another installation, the control module, no longer receiving the signal from its usual control center, detects an abnormal situation and triggers a degraded random operation mode.

Advantageously, the identification of the panel near the control center can be protected. For example, a COM control module register may contain a unit code that allows identification of the panel in the installation by means of a public key encryption algorithm (128-bit AES algorithm for example). The protection mechanism (step 41 of FIG. 4 described below) can be performed:

- by the command module on order of the control center, using a unit code and specific to the panel to differentiate the activation information stored in the different panels: thus, the diversion of a given panel, alone, can to be specifically detected; the protection information is stored in a protected memory area of the control module so as not to make it easy to disable it, by verifying the validation of the protection information which may occur for example every morning and in particular at each start of the installation of the panels, on the basis of the preceding protection information stored in memory: such an embodiment makes intervening a reading of the protection information loaded in a preferably volatile memory zone in order to overcome any "offline" modifications (necessarily leading to a reset on the next connection).

Thus, with reference to FIG. 4, following an initialization step 40, an activation of the protection (according to a routine in non-volatile memory) is implemented in step 41. A panel identification procedure is then applied (test step 42). If this procedure is successful ("yes" arrow at the output of the test 42), the control module activates the operation in "normal" mode of the panel at the maximum power PM (step 45). In case of failure in verifying the identity of the panel ("no" arrow at the output of test 42), the control module activates the operation in "degraded" mode of the panel at a power that varies randomly in time and intermediate between 0 and the maximum power PM (step 43). In both cases, it is preferentially applied a delay (step 44) before a new interrogation (implementation of the test 42). In a given embodiment, the panel is taken offline by disconnection (for example at night), at the end step 46.

In degraded mode, the output power (controlled voltage and / or current) can be for example equal to 1% of the maximum value PM for a time t1, then go to 10% for a time t2, then 5% during a time t3, etc. It will be preferred for example that the operating time at high power (for example 10%) is lower than that of operation at low power (for example 1%). Thus, with reference to FIG. 5, the operation in "normal mode" is at the point of maximum power A. In the event of disconnection of the (vol) and reconnection panel on another installation, the control module defaults to normal operation at point A and then checks whether the panel is part of a original installation of network panels. If this is not the case, the control module initially drives a standard operation for a predefined time and then drives a degraded operation at point B (1% of the maximum power) then at point C, and so on (D, E, ...) during a day. This pseudo-random change constantly modifies the operation of the panel which becomes unstable and difficult (if not impossible) to manage.

In case of recovery of the photovoltaic panel, it is possible to reconfigure it to make it its original operation, stable at maximum power (point A of Figure 5). However, deactivation of the degraded mode is then possible only by application of a specific procedure (entry of a valid unit code by a maintenance personnel for example).

Of course, the present invention is not limited to the embodiment described above by way of example; it extends to other variants.

Thus, for example, it will be understood that the location means (radiofrequency in the example presented above) may be implanted in the photovoltaic panel while being independent of the control module, but connected thereto by a circuit or the like.

In addition, a control module connected to a single panel has been described above. Alternatively, there may be provided a single control module for controlling a plurality of respective panel regulators. In such an embodiment, the breaking of a connection of a regulator to the control module causes the degraded operating mode of the panel comprising this regulator.

Claims

1. A method of controlling the operation of at least one photovoltaic panel, said panel being arranged to operate according to at least one nominal operating point corresponding to a maximum power (PM) produced by the panel,

the panel being connected to a control module for controlling the operation of the panel,

the control module being arranged to control the operation of the panel according to at least:

said nominal operation at maximum power, or

- according to a degraded operation of the panel,

characterized in that said degraded operation corresponds to a power output lower than said maximum power (PM) and not zero.

2. Method according to claim 1, characterized in that the control module controls the operation of the panel, in voltage, and in that said degraded operation, the voltage applied to the panel is intermediate between a zero voltage and a corresponding voltage at said maximum power.

3. Method according to one of claims 1 and 2, characterized in that the control module is:

- integrated into the panel and

- Connected to an inner panel of the panel, on the one hand, and to one or more connection cables to a distribution network, on the other.

4. Method according to claim 3, characterized in that the control module comprises means for detecting a cable cutoff connection to the distribution network, and in that the control module is arranged to control the degraded operation in case of detection of a cut of one or more connection cables of the panel to the distribution network.

5. Method according to one of claims 3 and 4, characterized in that the control module comprises a controller and means for controlling the controller.

6. Method according to one of the preceding claims, characterized in that the control module is arranged for:

detect a modification in a signal reception from a control center

- and, if necessary, trigger the degraded operation of the panel.

7. Method according to one of the preceding claims, characterized in that the control module comprises radiofrequency means of position change detection, and in that the control module is arranged to control the degraded operation in case of detection of position change.

8. Method according to one of the preceding claims, characterized in that, in said degraded operation, said control module delivers a succession of operating instructions of the panel to powers all intermediate between said maximum power (PM) and the power zero .

9. The method of claim 8, characterized in that said succession is random in time.

10. Method according to one of claims 8 and 9, characterized in that said operating power intermediate between said maximum power (PM) and the power zero are randomly selected.

1 1. Method according to one of claims 9 and 10, characterized in that the control module comprises a generator of pseudo-random sequences.

12. Module for controlling the operation of at least one photovoltaic panel, comprising: means for controlling said panel to operate according to at least one nominal operating point corresponding to a maximum power (MW) that the panel produces, and

means for receiving an interruption instruction of said nominal operation for controlling a degraded operation of the panel,

characterized in that said degraded operation corresponds to an intermediate power output between said maximum power (PM) and zero power.

13. Module according to claim 12, characterized in that it further comprises means for implementing the method according to one of claims 2 to 1 1.

14. Photovoltaic panel, comprising a control module according to one of claims 12 and 13.

15. Computer program comprising instructions for implementing the method according to one of claims 1 to 1 1, when the program is executed by a processor.