Off-Grid adapter for on-grid photovoltaic solar router

Abstract

The problem to be solved is, for a photovoltaic installation (1), to use a "solar router" (6) normally designed to operate with a connection to an electrical distribution network (on-grid), and to make it operate even without a connection (off-grid) to this electrical distribution network. The solution is to use an electronic processing unit (10) that measures in real time the surplus of unused photovoltaic energy thanks to, on the one hand, a light sensor (8), and on the other hand, an intensity sensor (15a or 15b) positioned on the power cable (input or output) of the inverter (3). The signal (12) generated by said processing unit / adapter (10) is then compatible with the operation of said "solar router" (6). Figure for the Summary: [Fig. 1]

Description

Title of the invention: Off-Grid adapter for On-Grid photovoltaic solar router Technical field of the invention

[0001] The present invention relates to the field of photovoltaic solar energy and more particularly to the field of "solar routers" which measure and manage the surplus of photovoltaic energy which becomes available when the photovoltaic generator, with regard to its sunshine, supplies electrical devices with a power which is less than its production potential at the moment. Technical background

[0002] A solar photovoltaic generator produces a direct current (DC) which is converted by an inverter into an alternating current (AC) that powers electrical devices when the generator's potential solar power output is greater than or equal to the power consumption demanded by said electrical devices, including electrical energy storage devices, which may be of the electrical, chemical, or thermal battery type. Generally, when the generator's potential power output exceeds the power consumption demanded by said electrical devices, there is a surplus of electrical energy that is neither consumed nor stored, and is therefore lost.This most often occurs during periods of strong sunlight, under clear skies, when the sun is high in the sky and few electrical appliances, or only low-power appliances, are in use. To best manage this potential energy surplus, some inverters measure this surplus in real time and feed it back into the public electricity grid, which is connected to the photovoltaic generator. However, when the photovoltaic generator is not connected to a public electricity grid, many inverters are unable to redirect all of this surplus photovoltaic power to electrical appliances, which could then consume all of it.There are devices that detect the presence of excess energy and momentarily activate electrical devices whose operating power is theoretically less than the available power, with the drawback of having to manage in a complex way several devices of different power and priorities with a very variable real-time sunlight.

[0003] Other “solar router” type devices exist which allow, in a relatively simple way, the consumption of all the surplus photo energy While photovoltaic, the real-time measurement of this surplus is achieved by installing an AC current sensor on the electrical cable used by the inverter to feed this surplus back into the public electricity grid. These devices therefore do not operate in isolated locations (off-grid) since there is no connection to a public electricity grid, as is very often the case in developing countries.

[0004] A patented device (No. FR2008557 of 19 / 08 / 2020) is known which allows the determination and management of the surplus of electrical energy potentially available at the terminals of a photovoltaic generator even when it is not connected to an electrical distribution network;The said patented device determines the surplus of electrical energy by means of a direct current sensor which is traversed both by the electrical cable coming out of the photovoltaic solar panels, the intensity of the electrical current flowing through which represents the electrical power consumed in real time by the devices, and by the electrical cable coming out of a control photovoltaic cell which is placed and oriented outside to receive the same sunlight as the solar panels of the said generator so that the electrical current flowing through the said cable represents in real time the maximum potential electrical power that the said generator could provide, depending on the theoretical power of the generator and the intensity of the sunlight at the moment; the said direct current sensor measures the difference between the two intensities of the two currents which flow in opposite directions in the two cables;This measurement then represents the surplus of available photovoltaic energy that can be consumed in full and in real time by auxiliary devices. However, this patented device can only replace the "solar routers" already on the market, which operate with a connection to a public electricity distribution network (On-Grid). It would be more economical to keep these "solar routers" on the market (often very sophisticated) and give them an inexpensive way to operate in offline mode, disconnected from a public electricity network (Off-Grid in English). Presentation of the invention

[0005] The object of the invention is therefore to describe a device which connects to a "solar router" of the (On-Grid) type which, in the basic sense, only works in the presence of a public electricity network, so as to make it functional even in the absence of a public electricity network (Off-Grid). Summary of the invention

[0006] A photovoltaic device comprises: - at least one photovoltaic solar panel (1) capable of producing a current continuous electrical current proportional to the intensity of the solar radiation (2) it receives, an inverter (3) capable of transforming said direct current into a sinusoidal current, a first set of at least one electrical device (5) powered by said sinusoidal electric current, a second set of at least one electrical device (7) powered by said sinusoidal electric current, a solar router (6) capable of directing the surplus photovoltaic energy not consumed by said first set of at least one electrical device (5) to said second set of at least one electrical device (7), said solar router (6) is capable of receiving a sinusoidal electrical signal (13) generated by an electrical intensity sensor (14) positioned around the power cable of the public electrical network (4) and which is representative of the intensity of the electrical current which is injected by said inverter (3) into a public electrical network (4), said solar router (6) includes at least one electrical connector (A) capable of receiving and processing said sinusoidal electrical signal (13), a device (B) for calculating the surplus of available and unconsumed photovoltaic energy, comprising (under references: 8, 9, 11a or 11b, 12, 15a or 15b): • a cable carrying an electrical signal (9) connected to a photoelectric sensor (8) which receives the same solar radiation (2) as that received by said photovoltaic panels (1), and which transmits at every instant an electrical signal (9) representative of the maximum electrical intensity that said solar panels (1) could produce; said photoelectric sensor (8) can be for example: a photoresistor, a phototransistor, a photodiode, a pyranometer, a photovoltaic surface. • a cable carrying an electrical signal (lia), connected by means of an electrical intensity sensor (15a), to the electrical circuit located at the output of the solar panels (1) or a cable carrying an electrical signal (11b) connected by means of an intensity sensor (15b) to the electrical circuit located at the output of the inverter (3), (or possibly connected to the inverter (3) itself) and which transmits at every instant said electrical signal (continuous lia or sinusoidal 11b) representative of the electrical intensity produced by said solar panels (1); • an electrical box (10) which receives the signals (9, 1 la or 11b) and which calculates the difference between the potential production power of the solar panels (1) and the power actually consumed by the electrical devices (5, 7);

[0007] said box (10) which calculates the surplus photovoltaic energy is characterized in that it generates a sinusoidal electrical signal (12) which is representative of said surplus photovoltaic energy and which is identical (or compatible and interchangeable) with said sinusoidal electrical signal (13) which is received and processed by said solar router (6); so that said electrical signal (12) can be received and managed by said solar router (6) by means of said connector (A) and in place of said signal (13); said box (10) for calculating the surplus photovoltaic energy thus allows the solar router (6) to operate even in the absence (Off-Grid in Anglo-Saxon terminology) of the public electrical network (4).

[0008] In an advantageous embodiment, said calculation unit (10) calculates the surplus photovoltaic energy by means of an electronic microcomputer or by means of an electronic circuit, known to those skilled in the art, so as to process the signals (9) and (11a or 11b) received by the connected cables and to generate an electrical signal (12) whose characteristics in intensity, in voltage and in frequency are identical or compatible with said signal (13) which is emitted by the electrical intensity sensor (14) positioned around the power cable of the public electrical network (4).

[0009] In another embodiment, said photovoltaic surplus energy calculation unit (10) generates a signal (12) which is transmitted to said solar router (6) by means of any type of digital or analog transmission, wired (electrical cable), wireless (electromagnetic waves) or optical (optical fiber or optoelectronic). Detailed description of the invention

[0010] The invention is now described in more detail with reference to the attached figure.

[0011] [Fig. 1] shows a schematic diagram of said invention. A photovoltaic device comprises a photovoltaic generator composed of photovoltaic solar panels (1) that receive solar radiation (2) and convert it into a direct current. An inverter (3) converts said direct current into a sinusoidal alternating current. Said inverter (3) also receives a power supply from a public electricity grid (4) when the power of the photovoltaic generator is insufficient. Said inverter (3) supplies, on the one hand, electrical devices (5) and, on the other hand, a management unit of the "solar router" type (6) whose function is to analyze the surplus electrical power not consumed by said electrical devices (5) and to supply other electrical devices (7) with this Surplus power. The solar router (6) receives a sinusoidal signal (13) from a current sensor (14) of the toroidal transformer type, which is placed around the cable from the public electricity grid (4) connected to the inverter (3). The inverter (3) can receive electrical current from the grid (4) or inject the surplus power from the photovoltaic generator (1) into the public electricity grid (4). When the inverter (3) injects the surplus photovoltaic power into the grid (4), the current sensor (4) sends a sinusoidal signal (13) to the solar router, which receives it via an electrical connection (A). This signal (13) represents the intensity of the injected current. The solar router then supplies the other devices (7) with the surplus power, so that the current injected into the public grid approaches zero.

[0012] When the photovoltaic device is not connected to a public electricity distribution network (4), the "solar router" (6) cannot function. In order to make maximum use of the potential surplus photovoltaic power that is not consumed, the device (B) according to the invention comprises, on the one hand: a current sensor (15a) placed on one of the electrical cables located between the solar panels (1) and the inverter (3), or a current sensor (15b) placed between the inverter (3) and the electrical appliances (5), so that the measured electrical current (in sinusoidal current (11b) or in direct current (1a)) is representative of the electrical power generated in real time by the photovoltaic generator (1), and on the other hand: a light sensor (8) which measures in real time the intensity of the solar radiation (2), for example, a photovoltaic cell,and which provides an electrical signal (9) representative of the current solar power and therefore of the maximum power that the photovoltaic generator (1) could produce; said electrical signals (11a or 11b) and (9) from the current sensors (15a or 15b and 9) are analyzed by an electronic unit (10) capable of calculating the difference S between the maximum potential power output of the generator (1) and the actual power consumption of all the devices (5 and 7). This difference S is then transformed into an electrical signal (12) representative of this difference S, and sent to the connector (A) of the "solar router" (6). Said electrical signal (12) is then identical, or compatible,to that (13) which the intensity sensor (14) would have generated if the photovoltaic device had been connected to a public electricity network (4). The "solar router" (6) can then operate by supplying the other electrical devices (7) with the surplus power thus measured by the calculation unit (10).

[0013] In the end, the box (10) for calculating the potential surplus of photovoltaic power made it possible to operate the said "solar router" (6) even when it was not connected (Off-Grid) to a public electricity distribution network (4). Examples

[0014] An example of an embodiment includes a 3 kWp (three kilowatts peak) photovoltaic system equipped with a hybrid inverter capable of operating either in "On-Grid" mode connected to a public grid such as EDF in France, or in "Off-Grid" mode, notably with a 2.4 kWh lithium backup battery. Under an EDF contract, the inverter is able to feed surplus solar power into the EDF grid and sell it for sale. However, the contract is for a limited time, and the selling price per kWh to EDF has become very low. The user has therefore terminated their contract with EDF to self-consume their photovoltaic production. To best manage their electricity production, however, the user needs a "solar router" which will supply power, among other things, to their domestic hot water tank when other household appliances are not in use.However, commercially available solar routers do not function when surplus solar energy is not fed into the grid. The user then uses an off-grid adapter according to the invention (10) and connects it near the inverter (3) so that the current sensor (transformer type) (15b) is positioned on the inverter's output cable (3). They also connect a photovoltaic cell (8) to the housing (10) so that the cell is oriented parallel to the photovoltaic panels (1) of their installation. Finally, they connect the signal cable (12) between the housing (10) and the signal socket (A) of the commercially available solar router (6). The solar router (6) is then connected and receives the 230V sinusoidal power supply from the inverter (3). The solar router (6) then supplies power to two 1.5 kW electric water heaters (7).The unit (10) measures in real time the brightness of the sky (2) and the house's electricity consumption via the sensor (15b). Using a microcomputer, it calculates the difference at each moment between the intensity of the reference cell (8) and the intensity output from the inverter (3), which represents the intensity of the photovoltaic production consumed by the household appliances (5 and 7). Calculating this difference in intensity requires adjustments to the voltage and shape, since, on the one hand, the capture areas of the cell (8) and the panels (1) are very different (by a factor of approximately 1:150), and on the other hand, the current transformers (generally 1:1000) are different because, in the case of the cell (8), a direct current is measured, while for the inverter output, an alternating current is measured.But the factory programming of the microcomputer enables it to perform the correct calculations in order to generate a sinusoidal signal (12) whose intensity and voltage are identical to those expected by said "solar router" by means of its electrical connection (A). Said "solar router" (6) then produces an electrical supply received by said water heater (7) whose power is variable and substantially. equivalent to the surplus solar energy not consumed by other devices (5). To allow for variable power supply, the "solar router" (6) uses a PWM (Power Wave Modulation) device known to those skilled in the art. Ultimately, the user achieved average annual savings of over 35% using a commercially available "On-Grid" type "solar router" supplemented by an "Off-Grid" adapter (10) according to the invention. ADVANTAGES OF THE INVENTION

[0015] In conclusion, this invention (10) makes it possible to equip oneself with a "solar router" designed for use with the grid (On-Grid) in an off-grid environment. This device is particularly interesting in developing countries where many villages are isolated without connection to an electricity distribution network.

Claims

1. Claims - Photovoltaic device comprising: - at least one photovoltaic solar panel (1) capable of producing a direct electric current proportional to the intensity of the solar radiation (2) that it receives, - an inverter (3) capable of transforming said direct electric current into a sinusoidal electric current, - a first set of at least one electrical device (5) powered by said sinusoidal electric current, - a second set of at least one electrical device (7) powered by said sinusoidal electric current, - a solar router (6) capable of directing the surplus photovoltaic energy not consumed by said first set of at least one electrical appliance (5) to said second set of at least one electrical appliance (7), said solar router (6) is capable of receiving a sinusoidal electrical signal (13) generated by an electrical intensity sensor (14) positioned around the power cable of the public electrical network (4) and which is representative of the intensity of the electrical current which is injected by said inverter (3) into a public electrical network (4), said solar router (6) comprises at least one electrical connector (A) capable of receiving and processing said sinusoidal electrical signal (13), - a device (B) for calculating the surplus photovoltaic energy available and not consumed, comprising: • a cable carrying an electrical signal (9) connected to a photoelectric sensor (8) which receives the same solar radiation (2) as that received by said photovoltaic panels (1), and which transmits at each instant an electrical signal (9) representative of the maximum electrical intensity that said solar panels (1) could produce; said photoelectric sensor (8) can be for example: a photoresistor, a phototransistor, a photodiode, a pyranometer, a photovoltaic surface. • a cable carrying an electrical signal (lia), connected by means of an electrical intensity sensor (15a), to the electrical circuit located at the output of the solar panels (1) or a cable traversed by an electrical signal (11b) connected by means of an intensity sensor (15b) to the electrical circuit located at the output of the inverter (3), (or possibly connected to the inverter (3) itself) and which transmits at each instant said electrical signal (1 IA continuous or 11b sinusoidal) representative of the electrical intensity produced by said solar panels (1); • an electrical box (10) which receives the signals (9, 11A or 11b) and which calculates the difference between the potential production power of the solar panels (1) and the power actually consumed by the electrical devices (5, 7); said box (10) which calculates the surplus photovoltaic energy is characterized in that it generates a sinusoidal electrical signal (12) which is representative of said surplus photovoltaic energy and which is identical (or at least compatible and interchangeable) with said sinusoidal electrical signal (13) which is received and processed by said solar router (6); so that said electrical signal (12) can be received and managed by said solar router (6) by means of said connector (A) in replacement of said signal (13); said box (10) for calculating the surplus photovoltaic energy thus makes it possible to operate the solar router (6) even in the absence (Off-Grid in English terminology) of the public electricity network (4).

2. - Box (10) for calculating the surplus photovoltaic energy according to the re preceding claim 1, characterized in that the calculation of said surplus is done by means of an electronic microcomputer or by means of an electronic circuit which processes the signals received by the connected cables (9) and (11a or 11b) so as to generate an electrical signal (12) whose characteristics in intensity, voltage and frequency are identical or compatible with said signal (13) which is emitted by the electrical intensity sensor (14) positioned around the power cable of the public electricity network (4).

3. - Box (10) for calculating the surplus photovoltaic energy according to one of of the preceding claims, characterized in that said signal (12), representative of the surplus photovoltaic energy available, is transmitted to said solar router (6) by means of any type of digital or analog transmission, wired (electric cable), wireless (electromagnetic waves) or optical (optical fiber or optoelectronic).

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