Photovoltaic device

Abstract

The present description relates to a device (3) comprising: at least one photovoltaic energy collector; an element (35) for storing the electrical energy harvested by the collector; a circuit (37) for measuring the voltage across the terminals of the collector; and an element (39) for switching between the collector on one hand and the storage element and the measuring circuit on the other hand.

Description

DESCRIPTION TITLE: Photovoltaic device This application is based on, and claims priority from, French patent application number 2308159, filed on July 28, 2023 and entitled "Photovoltaic Device", the contents of which are incorporated by reference to the extent permitted by law. Technical field

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

[0002] Photovoltaic sensors are widely used to power point elements in indoor spaces. This can be to power 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 compared to the photovoltaic panels installed on the roofs of buildings or in photovoltaic power plants and can take various forms.

[0004] When combined with lighting devices, photovoltaic sensors are sometimes also combined with infrared detectors to control the switching on of the lighting. These devices can also be combined to a brightness sensor in order to control the triggering of the lighting in relation to a darkness threshold. Summary of the invention

[0005] There is a need for improvement of indoor lighting installations depending on the brightness.

[0006] One embodiment overcomes all or part of the drawbacks 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; and a switching element between the sensor on the one hand and the storage element and the measurement circuit on the other hand.

[0008] According to one embodiment, the measurement of the voltage at 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 photovoltaic panel in the shape of a truncated cone carried by a housing of the device.

[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 set by the least illuminated cell or area of ​​the panel.

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

[0015] According to one embodiment, said screen constitutes a projecting 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 system for managing the lighting of 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 setting. Brief description of the drawings

[0019] These and other features and advantages will be set forth in detail in the following description of particular embodiments given without limitation in relation to the attached figures, among which:

[0020] Figure 1 represents, very schematically, an embodiment of a system for managing the lighting of an interior space;

[0021] Figure 2 represents, very schematically, an embodiment of a device of the system of Figure 1;

[0022] Figure 3 represents, very schematically, another embodiment of a device of the system of Figure 1; and

[0023] Figure 4 is a schematic and functional view of the device of Figure 3. Description of the embodiments

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

[0025] For the sake of clarity, only the steps and elements useful for understanding the embodiments described have been shown and are detailed. In particular, the production of a photovoltaic panel has not been detailed, the embodiments described being compatible with standard 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 connected (in English "coupled") together, this means that these two elements can be connected or be connected by means of one or more other elements.

[0027] In the following description, when referring 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", "upper", "lower", etc., or orientation qualifiers, such as the terms "horizontal", "vertical", etc., are referred to, unless otherwise specified, the orientation of the figures or to a photovoltaic device in a normal position of use.

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

[0029] The embodiments described provide for taking advantage of the presence of a photovoltaic panel in an electrical or electronic device arranged in an interior space to facilitate and optimize the control of the level of artificial lighting in this interior space. More particularly, the embodiments described provide for saving on a dedicated brightness sensor and using the photovoltaic sensor to estimate the brightness of the interior space.

[0030] To do 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 brightness in the vicinity of the device.

[0031] Figure 1 represents, in a very schematic manner, an embodiment of a system for managing the lighting of an interior space.

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

[0033] A device 3 according to the embodiments described 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 an 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] Figure 2 represents, very schematically, an embodiment of a device 3 of the system of Figure 1.

[0036] The device 3 has, in this example, a generally cylindrical shape.

[0037] The device 3 comprises, 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 lower face of a housing 33 of the device 3.

[0038] The housing 33 of the device defines a housing for different elements including: an element 35 for storing the electrical energy recovered by the sensor 31, this storage element being able to be, depending on the applications, one or more batteries and / or one or more capacitors; a circuit 37 for measuring the voltage across the sensor 31, this circuit using, 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 measuring circuit 37.

[0041] When connected to the measuring circuit 37, the panel 31 can be considered to be off-load, that is to say that it does not supply any energy. For example, the measuring circuit 37 has an input impedance high enough not to disturb the measurement result. The circuit 37 then measures the no-load voltage across the terminals of the panel 31. This no-load voltage is representative of the illumination received by the panel 31, 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 adapts the intensity of the lighting source 2 in order to maintain the illumination of the workstation 4 at a set value.

[0043] The measurement is preferably carried out periodically, in order to adapt the lighting of the workstation 4. Consequently, 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 the minute and the hour, preferably less than 5 minutes. Furthermore, in order to preserve the supply of energy by the sensor 31 to the device 3, the duration of the periods in which the sensor 31 is connected to the measuring circuit 37 is less, by a ratio of at least 10, preferably of the order of 20, than the duration during which the sensor 31 is connected to the energy storage element 35.

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

[0045] Thus, in the embodiment of Figure 2, the device 3 is equipped with a screen 6 blocking out 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 mainly captures the light coming from below, therefore from the workstation 4.

[0046] Depending on the environment of the device, the latter can be equipped with several sections of skirt 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 completely surrounds the sensor 31 so as to concentrate the brightness measurement directly above the area of ​​interest 4 (workstation or other).

[0048] Figure 3 represents, very schematically, another embodiment of a device of the system of Figure 1.

[0049] According to this embodiment, the sensor 31 is made up of one or more (several in the example shown) photovoltaic panels 312 in the shape of truncated cones 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) on the ceiling side of the interior space 1. Thus, the photovoltaic panels 312 capture mainly light directly above the device 3.

[0051] The embodiment of Figure 3 makes it possible to avoid the use of one or more occulting sections provided with continuous panels 312, that is to say that each panel 312 goes around the device. In this case, the illumination captured during the measurement periods (therefore 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 (wound) to the housing 33 and connected in parallel or in series depending on the requirements 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 the device 3. It will 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 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 either to a second terminal 394 or to a third terminal 396, and is controlled by a signal received from the controller 5 on a terminal 398. 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 the element 35 and of the circuit 37 are connected (if necessary by a switch controlled by the circuit 5 such as the switch K) to the negative terminal (-) of the sensor 31. The circuit 37 is furthermore connected to the controller 5 responsible for interpreting the measurements.

[0056] The representation of Figure 4 is only schematic and functional and many practical embodiments within the reach of the person skilled in the art could 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, therefore the least illuminated area of ​​the circumference. Thus, the voltage produced is limited by the least illuminated area. Advantage is taken of what may otherwise appear to be a disadvantage to measure and regulate the brightness around the area of ​​interest 4. This is particularly advantageous in the case of a workstation because an inhomogeneity of the illumination in the area causes visual fatigue and a drop in cognitive efficiency.In particular, in the case of 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 makes it possible to adjust. illumination based on the darkest peripheral area (for example, 500 lux is considered a level suitable for office work).

[0057] When installing a device 3 in an interior space 1, once the device 3 is in place, a procedure is implemented for calibrating the system according to this interior space and its particularities and in particular the positions of the natural light entry points and the artificial light sources 2. For example, one or more brightness measurements are carried out with a dedicated device, for example, a luxmeter, which is recorded or transmitted to the controller 5, and the corresponding value or values ​​of the open-circuit voltage at the terminals of the sensor 3 measured by the device 3 are transmitted in parallel. The microcontroller (programmed appropriately) can then calibrate or calibrate the system. This calibration then makes it possible to adjust the brightness to a set value recorded in the controller 5 in a reliable manner.

[0058] A calibration phase is preferably carried out at each change in the environment of the device 3 in the interior space 1 (for example, movement of the light sources 2, installation or removal of a light source 2, modification of the position of objects such as furniture likely to modify (statically) the light environment of the device 3.

[0059] A device as described, in particular in its embodiment of figure 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 variants could be combined, and other variants will occur to those skilled in the art. In particular, the choice between the embodiments of Figures 2 and 3 depends, among other things, on the function of the device 3 and its location.

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

Claims

CLAIMS 1. Device (3) comprising: at least one photovoltaic energy sensor (31), consisting of at least one photovoltaic panel (312) in the shape of a truncated cone carried by a housing (33) of the device (3); an element (35) for storing the electrical energy recovered by the sensor; a circuit (37) for measuring the voltage at the terminals of the sensor; and a switching element (39) 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 with no load.

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 comprising several concentric panels (312).

6. Device according to any one of claims 1 to 5, 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.

7. Device according to any one of claims 1 to 6, in which the sensor (31) further comprises one or several photovoltaic panels carried by a base of the housing (33).

8. Device according to any one of claims 1 to 7, in which said screen (6) constitutes a projecting element of the housing (33).

9. Method for controlling a device (3) according to any one of claims 1 to 8, 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).

10. Method according to claim 9, 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.

11. 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 8; and a microcontroller (5) controlling the level of artificial lighting according to a brightness setting.

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