Photovoltaic device

Abstract

Photovoltaic Device This description relates to a device (3) comprising: at least one photovoltaic energy sensor; an element (35) for storing the electrical energy recovered by the sensor; a circuit (37) for measuring the voltage across the sensor; and a switching element (39) between, on the one hand, the sensor and, on the other hand, the storage element and the measuring circuit. Figure for the abbreviation: Fig. 4

Description

Title of the invention: Photovoltaic device technical field

[0001] This description relates generally to photovoltaic sensors and, more particularly, to photovoltaic sensors intended for indoor spaces. This description applies more specifically to lighting management systems in indoor spaces or smart buildings. Previous technique

[0002] Photovoltaic sensors are widely used to power point elements in indoor spaces. These can include powering devices in an IoT (Internet of Things) application, presence detectors (e.g., infrared), cameras, lighting devices, control boxes, etc.

[0003] The photovoltaic panels used for such sensors are generally small in size compared to the photovoltaic panels installed on the roofs of buildings or in photovoltaic power plants and can take various forms.

[0004] When used with lighting devices, photovoltaic sensors are sometimes also combined with infrared detectors to control the lighting. These devices can also be combined with a light sensor to control the lighting activation based on a darkness threshold. Summary of the invention

[0005] There is a need to improve interior lighting installations according to the brightness.

[0006] One embodiment overcomes all or part of the disadvantages of known lighting installations.

[0007] One embodiment provides a device comprising: at least one photovoltaic energy sensor; an element for storing the electrical energy recovered by the sensor; a circuit for measuring the voltage across the sensor terminals; and a switching element between, on the one hand, the sensor and, on the other hand, the storage element and the measurement circuit.

[0008] According to one embodiment, the measurement of the voltage across the terminals of the photovoltaic sensor is carried out under no-load conditions.

[0009] According to one embodiment, the measurement is converted into brightness information received by the sensor.

[0010] According to one embodiment, the device further comprises a screen blocking the arrival of light on the sensor in one or more peripheral directions.

[0011] According to one embodiment, the sensor consists of at least one truncated cone-shaped photovoltaic panel carried by a device housing.

[0012] According to one embodiment, the device comprises several concentric panels.

[0013] According to one embodiment, the panel(s) are of the type in which the maximum electrical power supplied is fixed by the least illuminated cell or area of ​​the panel.

[0014] According to one embodiment, the sensor comprises one or more photovoltaic panels supported by a base of a device housing.

[0015] According to one embodiment, said screen constitutes a salient element of the housing.

[0016] One embodiment provides a method for controlling a device as described, comprising a step of switching said switching element so that it connects the sensor to the measuring circuit, a rest position of the switching element connecting the sensor to the energy storage element.

[0017] According to one embodiment, said step is periodic and of a duration at least 10 times less than the duration during which the switching element connects the sensor to the energy storage element between two switching operations.

[0018] One embodiment provides a lighting management system for an interior space comprising: one or more sources of artificial lighting; at least one device as described; and a microcontroller controlling the level of artificial lighting according to a brightness setpoint. Brief description of the drawings

[0019] These features and advantages, as well as others, will be described in detail in the following description of particular embodiments, given by way of non-limiting example, in relation to the accompanying figures, among which:

[0020] [Fig.1] represents, in a very schematic way, an embodiment of a lighting management system for an interior space;

[0021] [Fig.2] represents, in a very schematic way, an embodiment of a device of the system of [Fig.1];

[0022] [Fig. 3] represents, in a very schematic way, another embodiment of a device of the system of [Fig. 1]; and

[0023] [Fig.4] is a schematic and functional view of the device of [Fig.3]. Description of the implementation methods

[0024] The same elements have been designated by the same reference numerals in the different figures. In particular, structural and / or functional elements common to the different embodiments may have the same reference numerals and may have identical structural, dimensional and material properties.

[0025] For the sake of clarity, only the steps and elements necessary for understanding the described embodiments have been shown and detailed. In particular, the construction of a photovoltaic panel has not been detailed, as the described embodiments are compatible with conventional photovoltaic panels.

[0026] Unless otherwise specified, when referring to two elements connected together, this means directly connected without intermediate elements other than conductors, and when referring to two elements coupled together, this means that these two elements can be connected or linked through one or more other elements.

[0027] In the following description, when reference is made to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative position qualifiers, such as the terms "above", "below", "superior", "inferior", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., reference is made, unless otherwise specified, to the orientation of the figures or to a photovoltaic device in a normal operating position.

[0028] Unless otherwise specified, the expressions "approximately", "roughly", and "on the order of" mean within 10% or 10°, preferably within 5% or 5°.

[0029] The described embodiments take advantage of the presence of a photovoltaic panel in an electrical or electronic device located in an interior space to facilitate and optimize the control of the artificial lighting level in that interior space. More specifically, the described embodiments eliminate the need for a dedicated light sensor and utilize the photovoltaic sensor to estimate the brightness of the interior space.

[0030] To achieve this, the photovoltaic sensor, equipping an electrical or electronic device, is not connected directly and exclusively to an energy storage element (battery or capacitor) of the device, but can be connected either to this storage element or to a circuit for measuring the open-circuit voltage of the sensor panel(s). Thus, it becomes possible to use the open-circuit voltage to estimate the ambient light level in the vicinity of the device.

[0031] Fig. 1 represents, in a very schematic way, an embodiment of a lighting management system for an interior space.

[0032] In this example, an interior space 1 is lit both by natural light from a window or opening to the outside 12 and by artificial light from an electric lighting source 2.

[0033] A device 3 according to the described embodiments is placed (for example, fixed) to the ceiling, for example directly above a desk or work table. According to this example, one objective is to homogenize and optimize the lighting of the workstation. This is just one example, but the device 3 can also be placed above a workshop, a reading room, a kitchen area, a relaxation area, and, more generally, in any interior space, whether or not it benefits from natural light in addition to artificial light.

[0034] The artificial lighting management system further comprises a device or controller 5 (typically a microcontroller) comprising or associated with means of communication, preferably radio frequency, with the device 3 and the source 2. The microcontroller may be part of a separate control device 5 or be integrated into the device 3 or into the source 2.

[0035] Fig. 2 represents, in a very schematic way, an embodiment of a device 3 of the system of Fig. 1.

[0036] Device 3 has, in this example, a general cylindrical shape.

[0037] The device 3 includes, among other things, a photovoltaic energy sensor 31 in the form, here, of a circular photovoltaic panel (having the shape of a disc) and placed on the underside of a housing 33 of the device 3.

[0038] The housing 33 of the device defines a space for various elements, including: an element 35 for storing the electrical energy recovered by the sensor 31, this storage element being, depending on the application, one or more batteries and / or one or more capacitors; a circuit 37 for measuring the voltage across the terminals of the sensor 31, this circuit exploiting, for example, the measurement of the open-circuit voltage across the sensor terminals to provide information on the brightness captured by the sensor 31; and

[0039] a switching element or circuit 39 between, on the one hand, the sensor 31 and, on the other hand, the storage element 35 and the measuring circuit 37.

[0040] The switching circuit 39 has the role of connecting the terminals of the photovoltaic panel 31 either to the energy storage element 35 via an energy converter to adapt the voltage levels between the panel 31 and the storage element 35, or to the measurement circuit 37.

[0041] When connected to the measuring circuit 37, the panel 31 can be considered unloaded, i.e., it does not supply power. For example, the measuring circuit 37 has a sufficiently high input impedance so as not to interfere with the measurement result. Circuit 37 then measures the open-circuit voltage across panel 31. This open-circuit voltage is representative of the illumination received by panel 31, and therefore of the ambient brightness.

[0042] The brightness information is transmitted to the control device 5 and interpreted by the microcontroller it contains. The microcontroller then adjusts the intensity of the light source 2 in order to maintain the illumination of the workstation 4 at a setpoint value.

[0043] The measurement is preferably carried out periodically in order to adjust the lighting of the workstation 4. Therefore, the switching of the connection of the sensor 31 between the storage element 35 and the measuring circuit 37 is carried out periodically, for example, with a periodicity of between one minute and one hour, preferably less than 5 minutes. Furthermore, in order to preserve the energy supply from the sensor 31 to the device 3, the duration of the periods during which the sensor 31 is connected to the measuring circuit 37 is less, by a factor of at least 10, preferably on the order of 20, than the duration during which the sensor 31 is connected to the energy storage element 35.

[0044] In the described embodiments, the aim is to measure or estimate the brightness vertically (above) the device 3. In particular, the aim is to limit the influence of natural light coming through the window 12. However, the photovoltaic panel 31 is likely to capture light, including natural light, especially if it is not sufficiently far from a window or opening to the outside.

[0045] Thus, in the embodiment of [Fig.2], the device 3 is equipped with a screen 6 that blocks the light coming from the window 12. This blocking screen 6 is, for example, formed of a skirt, more precisely, of a section of skirt arranged to mask the panel 31 from the rays of natural light coming from the window 12. Thus, the panel 31 captures mainly the light coming from below, therefore from the workstation 4.

[0046] Depending on the environment of the device, it can be equipped with several skirt sections 6 in order to mask the rays coming from the source of natural light in several peripheral directions of the panel 31.

[0047] Alternatively, the skirt is complete, that is to say, it surrounds the entire sensor 31 so as to concentrate the brightness measurement directly above the area of ​​interest 4 (workstation or other).

[0048] Fig. 3 represents, in a very schematic way, another embodiment of a device of the system of Fig. 1.

[0049] According to this embodiment, the sensor 31 consists of one or more (several in the example shown) truncated cone-shaped photovoltaic panels 312 of circular revolution.

[0050] For example, several concentric conical panels 312 of different diameters are carried by a conical housing 33 of the device 3. The cone is oriented with its largest diameter (its base) towards the ceiling of the interior space 1. Thus, the photovoltaic panels 312 capture mostly light directly above the device 3.

[0051] The embodiment of [Fig. 3] avoids the need for one or more shading sections provided that continuous panels 312 are available, i.e., each panel 312 goes around the entire device. In this case, the illuminance captured during the measurement periods (i.e., the brightness measurement) is homogenized, whether this brightness is artificial 14 and comes from the interior space 1 or from natural light 16.

[0052] Preferably, flexible photovoltaic panels 312 are then used, attached (wrapped) onto the housing 33 and connected in parallel or in series according to the needs of the application.

[0053] Figure 4 is a schematic and functional view of the device of Figure 3.

[0054] In the example of Figure 4, the energy storage element 35, the measuring circuit 37, and the switching circuit 39 are shown outside of the device 3. It should be noted, however, that in practice, they are part of the device 3 and are inside the housing 33.

[0055] Figure 4 illustrates a functional example of a connection in which the positive (+) terminal of the sensor 31 (panels 312 connected in parallel or in series) is connected to a first terminal 392 of the switching circuit. A switch K connects this terminal 392 to either a second terminal 394 or a third terminal 396, and is controlled by a signal received from the controller 5 on a terminal 398. The terminal 394 is connected to a terminal of the energy storage element 35 (for example, a positive electrode of a capacitor or a voltage regulator connected to a battery). Terminal 396 is connected to a first (positive) terminal of the measuring circuit 37. The reference or negative potential terminals of element 35 and of circuit 37 are connected (where applicable by a switch controlled by circuit 5 such as switch K) to the negative (-) terminal of sensor 31. Circuit 37 is also connected to the controller 5 responsible for interpreting the measurements.

[0056] The representation in [Fig. 4] is only schematic and functional, and numerous practical implementations within the reach of a person skilled in the art can be envisaged depending on the application and, in particular, the nature of the device. 3. Each photovoltaic panel completely surrounds the device. Preferably, a panel technology is chosen in which the power produced by a panel is limited by the least illuminated cell of the panel, i.e., the least illuminated area of ​​the circumference. Thus, the voltage produced is limited by the least illuminated area. What might otherwise appear to be a drawback is used to measure and regulate the brightness around the area of ​​interest. This is particularly advantageous in the case of a workstation, as uneven lighting in the area causes eye strain and decreased cognitive efficiency. In particular, with conventional lighting such as an individual desk lamp, peripheral vision is plunged into darkness. Implementing the solution described with solar panels of the type described above allows the illumination to be adjusted according to the darkest peripheral area (for example, 500 lux is considered a suitable level for office work).

[0057] When installing a device 3 in an interior space 1, once the device 3 is in place, a calibration procedure is implemented for the system based on this interior space and its specific characteristics, particularly the positions of the natural light entry points and artificial light sources 2. For example, one or more measurements of the brightness are taken with a dedicated device, for example, a lux meter, and these measurements are recorded or transmitted to the controller 5. Simultaneously, the corresponding open-circuit voltage value(s) across the sensor 3, measured by the device 3, are transmitted. The microcontroller (appropriately programmed) can then calibrate the system. This calibration then allows the brightness to be reliably adjusted to a setpoint value stored in the controller 5.

[0058] A calibration phase is carried out, preferably, at each change in the environment of the device 3 in the interior space 1 (for example, moving light sources 2, installing or removing a light source 2, changing the position of objects such as furniture that may change (statically) the lighting environment of the device 3.

[0059] A device as described, in particular in its embodiment of [Fig.3], can be associated with an infrared detector of the type described in international application PCT / EP2023 / 065745.

[0060] Various embodiments and variations have been described. Those skilled in the art will understand that certain features of these various embodiments and variations could be combined, and other variations will be apparent to those skilled in the art. In particular, the choice between the embodiments shown in Figures 2 and 3 depends, among other things, on the function of device 3 and its location.

[0061] Finally, the practical implementation of the described embodiments and variants is within the reach of a person skilled in the art, based on the functional specifications given above. In particular, the practical implementation of the electronic controller for regulating lighting intensity according to a setpoint and The brightness information obtained from the described device is within the grasp of a person skilled in the art. The same applies to the integration of the elements of the described device into an electrical or electronic device, whether it be a lighting device or a device performing other functions (infrared detector, fan, etc.).

Claims

Claims

1. Device (3) comprising: at least one photovoltaic energy sensor (31); an element (35) for storing the electrical energy recovered by the sensor; a circuit (37) for measuring the voltage across the terminals of the sensor; and an element (39) for switching between the sensor on the one hand and the storage element and the measuring circuit on the other hand.

2. Device according to claim 1, in which the measurement of the voltage at the terminals of the photovoltaic sensor (31) is carried out in an off-load condition.

3. Device according to claim 1 or 2, in which the measurement is converted into brightness information received by the sensor (31).

4. Device according to any one of claims 1 to 3, further comprising a screen (6) blocking the arrival of light on the sensor (31) in one or more peripheral directions.

5. Device according to any one of claims 1 to 4 in which the sensor (31) consists of at least one photovoltaic panel (312) in the shape of a truncated cone carried by a housing (33) of the device (3).

6. Device according to claim 5 comprising several concentric panels (312).

7. Device according to claim 5 or 6, in which the panel(s) are of the type in which the maximum electrical power supplied is fixed by the least illuminated cell or area of the panel.

8. Device according to any one of claims 1 to 4, in which the sensor (31) comprises one or more photovoltaic panels carried by a base of a housing (33) of the device (3).

9. Device according to claims 4 and 8, wherein said screen (6) constitutes a projecting element of the housing (33).

10. Method for controlling a device (3) according to any one of claims 1 to 9, comprising a step of switching said switching element (39) so that it connects the sensor (31) to the measuring circuit (37), a rest position of the switching element connecting the sensor to the energy storage element (35).

11. Method according to claim 10, wherein said step is periodic and of a duration at least 10 times less than the duration during which the switching element (39) connects the sensor (31) to the energy storage element (35) between two switchings.

12. System for managing the lighting of an interior space (1) comprising: one or more sources (2) of artificial lighting; at least one device (3) according to any one of claims 1 to 9; and a microcontroller (5) controlling the level of artificial lighting according to a brightness setting.

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