System for integrating storage and / or expanding photovoltaic generation in existing installations and associated method

Abstract

The invention relates to a system for integrating storage and / or expanding photovoltaic generation in existing installations, wherein the existing installations comprise at least existing photovoltaic generation means connected, via electrical connection means, to at least one load requiring electrical energy and also connected, via an energy meter, to the general electrical grid. The system is characterised in that it comprises connecting a device with at least an inverter, a second electrical energy meter and a control unit, wherein the device: connects the existing installation to energy storage means; is connected, via the second electrical energy meter, to the general electrical grid in parallel with the existing photovoltaic generation means; and is configured to maintain a minimum use that is always equal to or greater than a predetermined compensation value.

Description

[0001]

[0002] SYSTEM FOR THE INTEGRATION OF STORAGE AND / OR EXPANSION OF PHOTOVOLTAIC GENERATION IN PREVIOUS INSTALLATIONS AND ASSOCIATED PROCEDURE

[0003] TECHNICAL SECTOR

[0004] The present invention falls within the sector of photovoltaic generation for self-consumption and storage.

[0005] Specifically, the present invention relates to a system for expanding existing photovoltaic plants for self-consumption, including both the installation of storage media and the installation of new photovoltaic panels, to improve the energy savings of the system. The present invention describes the operating procedure associated with the above system.

[0006] BACKGROUND OF THE INVENTION

[0007] Currently, there is a high demand for integrating storage systems into existing photovoltaic plants to achieve better use of the energy generated and savings in energy-related costs.

[0008] These upstream installations, in most cases, have a zero-injection system to prevent energy from being diverted to the general electrical grid. The zero-injection system works by defining a minimum consumption power that guarantees that no energy is diverted to the general electrical grid. Thus, when the energy demanded from the general electrical grid is lower than the minimum consumption power, demand is maintained at the minimum consumption power and photovoltaic generation is regulated to avoid surpluses, preventing the circulation of reverse energy flow. When installing a storage system or expanding photovoltaic energy generation facilities, a system is required that identifies when these surpluses occur, based on communication between the storage system and the upstream photovoltaic plant.

[0009] This poses a complex issue for the subsequent installation of storage, as there are a wide variety of brands and pre-assembled elements, which require customized components to properly establish communication between storage and generation.

[0010] Likewise, we can find other systems that aim to prevent the dumping of electrical energy into the general electrical grid.

[0011] In this regard, we can find document CN 106683390, which describes a home photovoltaic energy storage inverter with an electric energy meter, a first energy communication module, and a second energy communication module. Energy communication modules are added between the home photovoltaic energy storage inverter and the electric energy meter, which transmits acquired signal quantities to the home photovoltaic energy storage inverter via the energy communication modules. These measurements or signal quantities are used to control the entire system to achieve certain functions, such as self-generation for personal use and zero grid feeding.

[0012] Document JP2021002932 describes a power generation system with a power source, a PCS conditioner, a conversion unit, and a switch that connects or blocks the connection between the power conversion unit and the power generation source. It also comprises a reverse power relay that disconnects the PCS when reverse load flow from the PCS to the power system is detected. That is, the power relay detects reverse power flow when the amount of power generation exceeds the load power consumption, stopping the power generation system. After this, every time a certain period of time elapses, the PCS is restarted. If reverse power is detected, the PCS output power remains in the stopped state and reverse power is generated. If it is not detected, the PCS output power is output.Document US2022060026 describes an energy management system with a control unit that controls a power generating facility from a first source, and a second power generating device from a second source, which generates power independently of the first power generating device. It also comprises a power adjustment unit, which adjusts an amount of power supply to a load device that consumes the power generated by the power generating facility.

[0013] Specifically, the control unit comprises a determination unit that determines whether or not to execute a process of reducing an amount of energy generated by the facility, so that reverse energy does not flow into the power generation system.

[0014] Document JP2017169292A describes a device that controls and regulates power fed into the general power grid to meet utility-imposed constraints. This includes controlling an energy storage device that is efficiently charged with power generated in excess of the utility's constraints. Therefore, a control device for an energy storage device that stores generated power from a power generating device interconnected with the general power grid is described, and that predicts the amount of excess power generated by suppressing reverse power flow from the power generating device to the power system by performing output control.

[0015] Document JP2012175858 describes a photovoltaic power generation system that prevents the occurrence of reverse power flow, such that it can be used effectively even when there is a restriction preventing reverse power flow. To achieve this, the generated power does not correspond to the maximum achievable value, but is controlled to be equal to or less than a limiting power. In this way, by setting the limiting power, it is possible to suppress the generated photovoltaic power, eliminating excess power generation. As a result, the occurrence of reverse power flow is prevented. Document US10931112 describes a control device intended to store energy in an energy storage medium during times when there is a restriction on the discharge of electrical energy into the general electrical grid, such as during holidays.To this end, a device for controlling the generation and storage of renewable energy for self-consumption is described, through reverse flow prevention, which allows the generated energy to be automatically controlled for consumption only at the facilities of an electrical energy consumer or stored in storage equipment so that the generated renewable energy does not affect the commercial energy system on site.

[0016] Document US10944268 describes an isolated solar power generation system that is connected to the grid, with a solar electric power regulator that includes a microprocessor or microcontroller, configured to limit the production of electric power.

[0017] Document US2016164299 describes an apparatus for the optimized conversion and management of energy produced from renewable sources, adapted to control energy use in order to maximize the profitability of the management, while ensuring the optimization of the energy capture by the photovoltaic generator. To achieve this, the apparatus comprises an inverter module, an energy storage module, power measurement means that measure the input and output power from the inverter module and the power absorbed or supplied to the grid, and a switching module adapted to adjust the operation of said inverter module and of said switching module so that the combination of the value of the input and output to / from said inverter module and the value of the power absorbed or supplied to the grid.

[0018] In this way, the aim is to optimize energy capture for each demand situation, avoiding the appearance of surpluses or keeping them below a previously determined value.

[0019] Previous systems seek to prevent energy from being dumped into the general electricity grid by limiting the energy generated, and are therefore not optimized. Therefore, a system is needed that simplifies the integration of new plants, allowing both storage to accumulate surplus energy generated from photovoltaic plants that can be used when there is a drop in energy production, and the expansion of photovoltaic generation to optimize operation in combination with storage.

[0020] EXPLANATION OF THE INVENTION

[0021] The system for integrating storage and / or expanding photovoltaic generation and the associated operating method proposed by the invention is therefore configured as a notable novelty within its field of application, since, in accordance with its implementation and in a taxative manner, the objectives indicated below are achieved, with the characterizing details that make it possible and that distinguish them being conveniently included in the final claims that accompany this description.

[0022] Specifically, the present invention proposes a system that can be added to any existing self-consumption photovoltaic installation by connecting it in parallel to the electrical connection means. Additionally, the present invention also proposes expanding the photovoltaic installation by connecting new generators.

[0023] To achieve this, as can be seen in Figure 1 , a previous installation is used, which comprises at least some photovoltaic generation means (1 ), connected to one or more loads (2) through electrical connection means (3), which is also connected to the connection to the general electrical network. It also comprises an electric energy meter (4) at the input of the connection to the general electrical network.

[0024] Specifically, and as explained in the background section, the above installations must limit or eliminate the discharge of electrical energy into the general electrical grid. Therefore, the system has a defined minimum power consumption that is demanded from the general electrical grid, even in cases where photovoltaic generation is sufficient to supply the load, resulting in wasted energy surpluses. Based on the above, we find two operating situations in the above installations:

[0025] On the one hand, when photovoltaic generation exceeds the load demanded, only the minimum consumption power from the grid is consumed, and photovoltaic generation is regulated to avoid surpluses. In this case, excess energy equal to the photovoltaic generation plus the minimum consumption power, minus the load, could be generated; this excess energy could be utilized.

[0026] On the other hand, if photovoltaic generation is lower than the load, there is not enough power to supply the load, so the difference between the energy generated and the energy demanded by the load will be supplied through the general electrical grid.

[0027] We can observe an example of how this type of system works through the diagram in Figure 2, which shows an intermediate zone of photovoltaic generation, which is used to supply the electrical load, always maintaining the remaining consumption of the electrical grid configured from the minimum consumption power.

[0028] The present invention, as can be seen in Figure 3, proposes the connection of an additional device (5) with a second electric energy meter (8). The device (5) is used as a connection bridge between the previous photovoltaic installation and the new installation that is intended to be carried out. Specifically, the connection of the device (5) is made by connecting it in parallel to the electrical connection means (3), in this way it is possible to make the operation of the previous photovoltaic installation independent of the new installation.

[0029] The new installation may comprise storage means (6) to accumulate the generated photovoltaic surpluses and use them when production decreases, such as during hours of no sun. The particular difference is that, in the case of the invention, the surplus photovoltaic energy generated during hours of sunshine is not lost, but is stored in the storage means (6), and can be used later during hours of no light, or at times when photovoltaic generation decreases.

[0030] In this case, to ensure the operation of the energy storage facility, it is necessary to define a compensation value (9), which must be greater than the minimum consumption power to allow the charging of the storage media (6) since the zero-discharge management must be prevented from coming into operation, which would regulate the photovoltaic energy generated to adapt it to consumption needs. This would prevent surpluses from being generated and, therefore, would prevent the batteries from charging.

[0031] Starting from the compensation value (9), the system would be responsible for ensuring that the energy consumption of the electrical grid was always above it, so that at no time would the zero discharge function of the previous installation be activated.

[0032] It should be noted that, preferably and to optimize the operation of the system, the compensation value (9) would only be applied: during the hours of sunlight in which there is photovoltaic generation;

[0033] Therefore, if we are outside the photovoltaic generation hours, the device (5) through its control unit, would deactivate the compensation value (9). In these cases, since there is no photovoltaic generation, no surplus is generated and, therefore, the surplus management system that prevents the discharge of electrical energy into the grid does not come into operation.

[0034] According to the invention, the new installation may also comprise an expansion of the photovoltaic generation, starting from a second photovoltaic generation means (7), which increases the amount of energy generated. For example, this may be done in response to the fact that, by integrating energy storage means, the optimal size of the photovoltaic generation means is always larger than the size of the previous photovoltaic installation.

[0035] Considering the above, we find the following operating modes: Operation when the sum of the photovoltaic generation and the compensation value is greater than consumption

[0036] In this case, we have that the sum of the photovoltaic generation and the compensation value is greater than the energy demanded by the load, therefore, there is a surplus that is used to charge the storage media (6), demanding only from the electrical network the value corresponding to the compensation value (9).

[0037] Operation when the sum of the photovoltaic generation and the compensation value is lower than the consumption

[0038] Firstly, the difference between the generated photovoltaic energy and the consumption would be compensated by using the storage media (6), up to the point where they are not able to supply the consumption demanded by the load, demanding from the electrical network the value corresponding to the compensation value (9).

[0039] At this point, when the storage media (6) together with the photovoltaic generation are not sufficient to supply the consumption demanded by the load, the difference must be completed through the general electrical network.

[0040] Thanks to the described system and the associated operating method, a completely independent installation is achieved, allowing both the inclusion of storage media and the expansion of the installed photovoltaic generation in previously installed photovoltaic installations, which already include a zero-emission operating method, without the need to make modifications to the previous installation, and ensuring, at the same time, optimal use of the generated energy, achieving savings in energy costs.

[0041] The system for integrating storage and / or expanding photovoltaic generation, the associated operating method, and the set of elements described represent an innovation with previously unknown structural and constitutive characteristics. These reasons, combined with its practical usefulness, provide sufficient grounds for obtaining the exclusive privilege requested. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] To complement the description being made and in order to help better understand the characteristics of the invention, a set of drawings is attached as an integral part of said description, in which the following has been represented for illustrative and non-limiting purposes:

[0043] Figure 1.- Shows a diagram of a previous photovoltaic installation with photovoltaic generation means, and an energy meter between the installation and the general electrical network.

[0044] Figure 2.- Operating diagram of a previous photovoltaic installation with photovoltaic generation means, and an energy meter between the installation and the general electrical network.

[0045] Figure 3.- Graph with a representation of photovoltaic generation versus the electrical consumption of the load and the energy demand from the general electrical grid.

[0046] Figure 4.- Shows a diagram of a previous photovoltaic installation expanded with the system object of the present invention, which includes energy storage means and an expansion of photovoltaic generation.

[0047] Figure 5.- Operating diagram of a previous photovoltaic installation expanded with the system object of the present invention, which includes energy storage means and an expansion of photovoltaic generation.

[0048] Figure 6.- Graph of the operation of the system object of the present invention, including new storage media, with a representation of the photovoltaic generation versus the electrical consumption of the load and the energy demand to the general electrical network, in which the compensation value can be seen (9).

[0049] Figure 7.- Graph of the operation of the system object of the present invention, including new storage media and an extension of the photovoltaic generation, with a representation of the photovoltaic generation versus the electrical consumption of the load and the energy demand to the general electrical grid, in which the compensation value (9) can be seen. PREFERRED EMBODIMENT OF THE INVENTION

[0050] In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part of this specification, and in which specific preferred embodiments in which the invention may be carried out are shown by way of illustration.

[0051] These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is understood that other embodiments may be utilized and that structural, mechanical, electrical, and / or chemical changes may be made without departing from the scope of the invention. The avoidance of details not necessary to enable those skilled in the art to practice the detailed description should not, therefore, be taken in a limiting sense.

[0052] In the following preferred embodiments, it should be noted that the operation of the system has been analyzed based on a prior analysis of the zero-discharge operating mode of the previous installation.

[0053] Likewise, it should be understood that the complexity of the system has been ignored by considering that it is phase-balanced, in the case of three-phase installations, since the zero-discharge generation limitations arise from the lower limit of the minimum current of the network phases to ensure zero discharge.

[0054] The system described in the following embodiments allows unbalanced generation to compensate for this effect, so it is understood that the limitation of the power concept becomes a limitation of minimum current per phase to ensure the operation of the system.

[0055] Specifically, the present invention describes a system for the integration of storage and / or expansion of photovoltaic generation in previously existing photovoltaic installations, which comprise at least one means of photovoltaic generation (1), connected to at least one load (2) that demands electrical energy through electrical connection means (3), which are also connected to the general electrical network through an energy meter (4).Characterized in that it comprises the connection of a device (5) with at least one control unit, an inverter and a second electric energy meter (8), associated with the system object of the present invention; where the device (5): connects the previous installation with energy storage means (6), is connected to the general electrical network in parallel to the previous means of photovoltaic generation (1) through the second electric energy meter (8), is configured to maintain a minimum consumption that is always equal to or greater than a previously determined compensation value (9).

[0056] In this way, the system comprises a device (5) that is used to connect energy storage means (6), such as batteries, in parallel to the previous installation. Where the device (5) guarantees a minimum consumption that is always equal to or greater than a previously determined compensation value (9).

[0057] This system allows the operation of the previous installation to be independent from the storage media (6) installed.

[0058] Likewise, this system allows the use of surplus photovoltaic generation to charge energy storage media (6).

[0059] Specifically, the compensation value (9) must be higher than the minimum consumption power value defined in the previous installation, configured based on the zero discharge policy, to avoid the discharge of generated electrical energy into the general electrical grid.

[0060] This embodiment responds to the need to avoid the regulation of photovoltaic generation that balances generation with consumption without generating surpluses, so that the surpluses could not be used to charge the energy storage media. For this purpose, the compensation value (9) is defined as greater than the minimum consumption power value, so that the regulation of the photovoltaic generation installed in the previous photovoltaic generation facilities does not come into operation to avoid discharge to the general electrical grid. In another preferred embodiment, the compensation value (9) is only applied during the hours in which there is photovoltaic generation, and which coincide with the hours of daylight in which there is an impact on the photovoltaic generation means (1).

[0061] This implementation responds to the need to avoid higher than necessary consumption in cases where there is no surplus photovoltaic generation available for use, due to the lack of generation.

[0062] These latest projects aim to maximize the use of generated energy, optimizing consumption from the general electricity grid to reduce associated costs.

[0063] In another preferred embodiment, the system additionally includes second photovoltaic generation means (7) connected to the device (5), which are added to the previous photovoltaic generation means (1), to increase the electrical generation capacity.

[0064] This embodiment is mainly used to optimize the charge of the energy storage means (6), since it allows obtaining better results by ensuring the charge of the energy storage means (6) at times when there is no photovoltaic generation or it is insufficient to feed the consumption of the load (2), avoiding having to obtain electrical energy from the general electrical network.

[0065] The present invention also describes the operating procedure associated with the system for the integration of storage and / or expansion of photovoltaic generation in previous installations, according to any of the preceding claims, where the previous installations comprise at least one means of photovoltaic generation (1), connected to a load (2) that demands electrical energy through electrical connection means (3), such as a busbar, which are also connected to the general electrical network through an energy meter (4). Specifically, and as indicated previously, the system comprises a device (5) with an inverter, an energy meter (8) and a control unit, where the procedure comprises the definition of a compensation value (9), and the following operating conditions.

[0066] In the case where the generation of electrical energy from the photovoltaic generation means (1,7) is equal to zero, the compensation value (9) is equal to zero, so that the operating mode of the previous installation is activated.

[0067] In the case where the generation of electrical energy from the photovoltaic generation means (1,7) is different from zero, the compensation value (9) is different from zero and greater than the minimum consumption power, and the energy taken from the network is equal to or greater than the compensation value (9), to prevent the zero discharge of the previous installation from coming into operation.

[0068] In the above case, if the sum of the electric power generation from the photovoltaic generation means (1,7) and the compensation value (9), is greater than the electric consumption of the load (2), then the energy taken from the grid is equal to the compensation value (9), and the electric power generation and the energy taken from the grid are used to feed the electric consumption of the load (2) and to charge the energy storage means (6).

[0069] That is, photovoltaic generation and energy taken from the grid are used to supply the load, taking advantage of the surplus to charge the energy storage media (6). To optimize cost and consumption, the energy demanded from the electrical grid is equal to the compensation value (9).

[0070] Alternatively, if the sum of the generation of electrical energy from the photovoltaic generation means (1,7) and the compensation value (9) is less than or equal to the electrical consumption of the load (2), we find ourselves with insufficient generation of electrical energy.

[0071] First, the system attempts to call on the energy storage means (6). In this case, if the sum of the discharge of the energy storage means (6), the generation of electric energy and the compensation value (9), is greater than the electrical consumption of the load (2), then: the electric energy taken from the grid is equal to the compensation value (9), and the sum of the discharge of the energy storage means (6), the generation of electric energy and the energy taken from the grid, is used to feed the electrical consumption of the load (2).

[0072] Otherwise, i.e. the system attempts to go to the energy storage means (6), but the sum of the discharge of the energy storage means (6), the generation of electric energy and the compensation value (9), is less than or equal to the electric consumption of the load, then: the sum of the discharge of the energy storage means (6), the generation of electric energy and the energy taken from the grid, are used to feed the electric consumption of the load (2); where the energy taken from the grid is equal to the difference between the electric consumption of the load (2) and the sum of the generation of electric energy and the discharge of the energy storage means.

[0073] In particular, the compensation value (9) is higher than a minimum power consumption value of the previous photovoltaic installation, defined to apply a zero-discharge policy of the generated electrical energy to the general electrical grid.

[0074] Based on previous implementations and the associated procedure, we have developed a system that guarantees the optimization of a previous photovoltaic generation installation, as it allows for the addition of energy storage media, such as batteries or similar, which can be charged by taking advantage of the surplus energy generated when the right conditions exist, reducing energy consumption from the general electrical grid.

[0075] Likewise, we also have a system that optimizes its operation by combining storage media with new photovoltaic generation facilities. This ensures the energy storage media maintains charge when there is no photovoltaic generation, ensuring minimal use of the general electrical grid.

[0076] Having sufficiently described the nature of the present invention, as well as the manner of putting it into practice, it is not considered necessary to explain it further so that any expert in the field may understand its scope and the advantages derived from it, stating that, within its essence, it may be put into practice in other embodiments that differ in detail from the one indicated as an example, and to which it will also achieve the protection sought provided that its fundamental principle is not altered, changed or modified.

Claims

CLAIMS 1. System for the integration of storage and / or expansion of photovoltaic generation in previous installations, where the previous installations comprise at least one previous means of photovoltaic generation (1) connected to at least one load (2) that demands electrical energy through electrical connection means (3), which are also connected to the general electrical network through an energy meter (4) characterized in that it comprises the connection of a device (5) with at least one inverter, a second electrical energy meter (8) and a control unit, where the device (5): connects the previous installation with energy storage means (6), is connected to the general electrical network in parallel to the previous means of photovoltaic generation (1) through the second electrical energy meter (8), is configured to maintain a minimum consumption that is always equal to or greater than a previously determined compensation value (9),where the compensation value (9) is greater than a minimum power consumption value defined in the previous installation., 2. System according to claims 1 or 2, characterized in that the compensation value (9) is applied during the hours in which there is photovoltaic generation.

3. System according to any of the preceding claims, characterized in that it comprises second photovoltaic generation means (7), connected to the device (5).

4. Procedure associated with a system for the integration of storage and / or expansion of photovoltaic generation in previous installations, according to the previous claims, where the previous installations comprise at least some photovoltaic generation means (1) connected to at least one load (2) that demands electrical energy through electrical connection means (3), which are also connected to the general electrical network through an energy meter (4) characterized in that the system comprises a device (5) with a inverter, an energy meter (8) and a control unit, where the device (5) are connected to energy storage means (6); where the method comprises defining a compensation value (9), greater than a minimum power consumption value of the previous photovoltaic installation, and the following operating conditions: if the generation of electrical energy from the photovoltaic generation means (1, 7) is equal to zero, then the compensation value (9) is equal to zero;if the generation of electrical energy from the photovoltaic generation means (1,7) is different from zero, the compensation value (9) is different from zero, and the energy taken from the grid is equal to or greater than the compensation value (9): or if the sum of the generation of electrical energy from the photovoltaic generation means (1,7) and the compensation value (9), is greater than the electrical consumption of the load (2), then, the energy taken from the grid is equal to the compensation value (9), and the generation of electrical energy and the energy taken from the grid are used to feed the electrical consumption of the load (2) and to charge the energy storage means (6); or if the sum of the generation of electrical energy from the photovoltaic generation means (1,7) and the compensation value (9), is less than or equal to the electrical consumption of the load (2), then: ; • if the sum of the discharge of the energy storage media (6), the generation of electrical energy and the compensation value (9), is greater than the electrical consumption of the load (2), then: ■ the electrical energy taken from the grid is equal to the compensation value (9), ■ and the sum of the discharge of the energy storage media (6), the generation of electrical energy and the energy taken from the grid, are used to feed the electrical consumption of the load (2); • if the sum of the discharge of the energy storage media (6), the generation of electrical energy and the compensation value (9), is less than or equal to the electrical consumption of the load, then: ■ the sum of the discharge of the energy storage media (6), the generation of electrical energy and the energy taken from the grid, are used to feed the electrical consumption of the load (2); ■ where the energy taken from the grid is equal to the difference between the electrical consumption of the load (2) and the sum of the generation of electrical energy and the discharge of the energy storage media.

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