A solar frequency division energy storage system and method based on potential energy prediction

Abstract

This invention discloses a solar frequency-division energy storage system and method based on potential energy prediction, belonging to the field of solar energy comprehensive utilization and intelligent energy storage control technology. The system includes a spectral frequency divider, photovoltaic units, a thermochemical energy storage reactor, a phase change buffer layer, and a thermo-electric co-predictive controller. The spectral frequency divider uses the first and second wavebands for photovoltaic power generation and driving a reversible thermochemical reaction, respectively. The phase change buffer layer covers the reactor to suppress temperature fluctuations. The controller incorporates a dynamic energy storage potential energy prediction model and a multi-objective rolling optimization algorithm, generating optimal instructions based on irradiance, photovoltaic power, reaction progress, and load prediction, dynamically allocating electrical energy and adjusting the reaction rate. The method includes model initialization, acquisition of prediction data, rolling optimization solution, execution of co-operational instructions, state update, and repeated looping. This invention realizes solar frequency-division utilization and photovoltaic-thermochemical co-operational energy storage, improving system energy efficiency and stability through active prediction and rolling optimization.

Description

Technical Field

[0001] This invention relates to the field of solar energy comprehensive utilization and intelligent energy storage control technology, and in particular to a solar frequency division energy storage system and method based on potential energy prediction. Background Technology

[0002] The core challenge in solar energy utilization lies in the mismatch between its volatility and user demand. While existing technologies combine spectral frequency division with thermochemical energy storage, they generally employ independent control and passive response: the maximum power point tracking (MPPT) of photovoltaic units and the charge / discharge decisions of thermochemical units are disconnected. This results in the system's inability to predict and proactively optimize energy flow and storage methods in the face of rapidly changing cloud cover, seasonal transitions, and load fluctuations, leading to low overall energy efficiency and response speed. Furthermore, traditional energy storage solutions such as batteries suffer from short lifespans, high costs, and significant environmental impacts, while single sensible heat or phase change thermal energy storage has low energy density, making it difficult to achieve stable energy supply over long periods. Therefore, there is an urgent need for a high-efficiency, high-density solar energy storage system capable of proactively predicting and collaboratively planning photovoltaic and thermochemical energy flow paths. Summary of the Invention

[0003] The purpose of this invention is to provide a solar frequency-division energy storage system and method based on potential energy prediction, which solves the problems of the separation between photoelectric conversion and thermochemical energy storage decision-making, the inability to actively predict energy fluctuations, and the low overall energy efficiency in existing solar energy utilization systems.

[0004] To achieve the above objectives, the present invention provides a solar frequency division energy storage system based on potential energy prediction, comprising: A solar frequency-division energy storage system based on potential energy prediction, characterized in that it comprises: A spectrum divider receives solar radiation at its input and splits the solar radiation into a first band of light and a second band of light for output. A photovoltaic unit, wherein the light incident surface of the photovoltaic unit is optically coupled to the first band light output end of the spectral frequency divider, for converting the first band light into electrical energy; A thermochemical energy storage reactor, wherein the heat-absorbing surface of the thermochemical energy storage reactor is optically coupled to the second-band light output end of the spectral frequency divider, and the interior of the thermochemical energy storage reactor is filled with an energy storage medium for carrying out reversible thermochemical reactions. A phase change buffer layer is tightly wrapped around the outer wall of the thermochemical energy storage reactor to suppress transient temperature fluctuations inside the reactor. A thermoelectric co-predictive controller is electrically connected to the output of the photovoltaic unit, the state monitoring terminal of the thermochemical energy storage reactor, and an external energy management bus. The thermo-electric co-predictive controller incorporates a dynamic energy storage potential prediction model. This model executes a multi-objective rolling optimization algorithm based on real-time collected irradiance sequences, real-time output power sequences of the photovoltaic unit, reaction progress sequences inside the thermochemical energy storage reactor, and user-side load prediction sequences to generate a set of optimal control commands. These optimal control commands are used to dynamically allocate, in the next control cycle, whether the electrical energy output by the photovoltaic unit is directly supplied to the load, stored in the electrical energy storage device, or converted into heat energy through an electrothermal element to supplement the thermochemical energy storage reactor, and to dynamically adjust the forward endothermic reaction rate or reverse exothermic reaction rate of the thermochemical energy storage reactor.

[0005] Preferably, the mathematical expression of the dynamic energy storage potential prediction model is: ; in, The total energy storage potential of the system in the next time period is predicted. To predict irradiance, This represents the actual output power of the photovoltaic unit. This represents the real-time reaction conversion rate of the thermochemical energy storage reactor. This is the real-time molar enthalpy of reaction for this reversible thermochemical reaction. These are the weighting coefficients.

[0006] ; in, To predict load, This represents the total power supply of the system. For the target energy storage state, This represents the actual energy storage state. For energy conversion loss, As a dynamic weighting factor, To predict the length of the time domain.

[0007] Preferably, the thermo-electric co-predictive controller includes: An environmental sensing module is used to collect meteorological data, including solar irradiance, ambient temperature, and wind speed. A state monitoring module is used to collect the output voltage / current of the photovoltaic unit, the temperature and pressure inside the thermochemical energy storage reactor, and the temperature of the phase change buffer layer; A communication interface module is used to acquire user-side load forecast data; An optimization computing engine is used to run the dynamic energy storage potential prediction model and the multi-objective rolling optimization algorithm, and output the optimal control command.

[0008] Preferably, the system further includes a power distribution unit connected to the thermo-electric co-predictive controller, the power distribution unit having multiple output ports connected to the user load, the battery pack and the electrothermal element embedded inside the thermochemical energy storage reactor, respectively.

[0009] The present invention also provides a method for solar energy storage using the above system, comprising the following steps: Step S1: The thermoelectric co-predictive controller initializes the dynamic energy storage potential prediction model and collects the current state parameters of the system; Step S2: The thermal-electric co-predictive controller obtains the predicted irradiance sequence and predicted load sequence for the next prediction time domain through the environmental sensing module and the communication interface module; Step S3: The optimization calculation engine of the thermo-electric co-predictive controller aims to minimize the objective function of the multi-objective rolling optimization algorithm, solves the problem within the constraints, and generates the coordinated action command for the photovoltaic unit and the thermochemical energy storage reactor in the next control cycle. Step S4: The photovoltaic unit determines its maximum power point tracking mode or power limiting mode according to the first type of instruction; Step S5: The thermochemical energy storage reactor controls its endothermic or exothermic reaction rate by adjusting the valve opening, the power of the electric heating element, or the flow rate of the circulating pump according to the second type of instruction. Step S6: At the end of each control cycle, the thermo-electric co-predictive controller updates the state observations and rolls the prediction time domain forward by one step, repeating steps S3 to S5.

[0010] Preferably, in step S3, the constraints include: the reaction temperature of the thermochemical energy storage reactor does not exceed its upper temperature limit, the reaction conversion rate of the energy storage medium does not exceed its limiting conversion rate, and the output power of the photovoltaic unit does not exceed its maximum usable power.

[0011] Preferably, the reversible thermochemical reaction is a hydrogenation / dehydrogenation reaction of a metal hydride, a decomposition / synthesis reaction of a metal carbonate, or a dehydration / hydration reaction of a metal hydroxide.

[0012] Therefore, the solar frequency-division energy storage system and method based on potential energy prediction using the above structure of the present invention has the following beneficial effects: (1) The present invention divides the solar spectrum into different bands by using a spectrum divider. Short waves are used for photovoltaic power generation and long waves are used for thermochemical energy storage, which avoids the efficiency reduction of traditional photovoltaic cells caused by long wave heat load, and realizes the cascade utilization of energy.

[0013] (2) This invention introduces a dynamic energy storage potential energy prediction model and a multi-objective rolling optimization algorithm, enabling the system to proactively predict future energy fluctuations based on irradiance prediction and load prediction, and adjust the energy storage path and rate in advance, thus achieving a leap from passive response to proactive pre-compensation.

[0014] (3) The present invention sets up a phase change buffer layer to cover the thermochemical energy storage reactor, which effectively suppresses the transient temperature fluctuations during the endothermic / exothermic reaction process, prolongs the cycle life of the energy storage medium, and improves the thermal stability of the system.

[0015] (4) The present invention coordinates the power distribution of the photovoltaic unit and the reaction rate of the thermochemical reactor through a thermo-electric synergistic predictive controller, and uses electrothermal elements to convert excess power into heat energy for supplementation, thereby avoiding energy waste and significantly improving the overall energy efficiency of the system.

[0016] (5) The method provided by the present invention is applicable to a variety of reversible thermochemical reaction systems (metal hydrides, metal carbonates, metal hydroxides), and has broad material adaptability and application prospects.

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] Figure 1 This is a diagram showing the overall architecture and connection relationship of the solar frequency-division energy storage system based on potential energy prediction provided in this embodiment of the invention. Figure 2 This is a diagram showing the internal module structure and data flow of the thermo-electric co-predictive controller in an embodiment of the present invention. Figure 3 This is a system overall module block diagram provided in the embodiments of the present invention; Figure 4 This is the main flowchart of the solar energy storage method provided in the embodiments of the present invention. Detailed Implementation

[0019] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0021] Example 1 This embodiment provides a solar frequency-division energy storage system based on potential energy prediction. For example... Figure 1 As shown, the system includes: a spectral frequency divider, a photovoltaic unit, a thermochemical energy storage reactor, a phase change buffer layer, and a thermo-electric co-predictive controller.

[0022] The spectral divider is a dichroic mirror that separates sunlight into short-wave (400-900nm) and long-wave (900-2500nm) wavelengths. The short-wave wavelengths are reflected to the photovoltaic cells (using perovskite / silicon tandem cells), while the long-wave wavelengths are transmitted to the thermochemical energy storage reactor. The thermochemical energy storage reactor is a cylindrical pressure vessel filled with a MgH2 / Mg energy storage medium, where a reversible reaction occurs: MgH2(s) + heat ⇌ Mg(s) + H2(g). The phase change buffer layer is an aluminum-silicon alloy phase change material coating the outer wall of the reactor, and its phase change temperature matches the reaction equilibrium temperature (approximately 350-400℃).

[0023] Figure 2 The internal structure of the thermoelectric co-predictive controller is demonstrated. It includes: an environmental sensing module (containing an irradiance meter and an anemometer), a state observation module (containing voltage / current sensors, thermocouples, and pressure sensors), a communication interface module (for receiving load forecasts from the cloud), and an optimization computing engine (based on an ARM Cortex-A series processor, running model predictive control algorithms). The controller is connected via signal lines to the maximum power point tracking controller of the photovoltaic unit, the exhaust valve and internal heating elements of the thermochemical energy storage reactor, and the power distribution unit. The input of the power distribution unit is connected to the photovoltaic unit, and the output is divided into three paths: one path connects to the user load via an inverter, one path connects to the battery pack, and one path connects to the heating wire embedded inside the thermochemical energy storage reactor.

[0024] Figure 3The system's overall module block diagram clearly illustrates the energy flow and control signal flow relationships between each module. Solar radiation is input to a spectrum divider. After frequency division, the first band of light enters the photovoltaic unit and is converted into electrical energy, while the second band of light enters the thermochemical energy storage reactor to drive an endothermic reaction. The thermo-electric co-predictive controller collects the output power of the photovoltaic unit, the temperature and pressure of the reactor, and the reaction progress. Combined with load forecasts and meteorological data obtained from the communication interface module, it runs a built-in dynamic energy storage potential prediction model and a multi-objective rolling optimization algorithm to generate optimal control commands. These commands adjust the maximum power point tracking mode of the photovoltaic unit on one hand, and control the opening of the reactor's exhaust valve and the heating power of the internal electric heating elements on the other. The power distribution unit distributes the electrical energy output from the photovoltaic unit to user loads, battery banks, or electric heating elements according to the commands. The electric heating elements can convert excess electrical energy into heat energy to supplement the reactor. When energy release is required, the reactor undergoes a reverse exothermic reaction, and the released heat is converted into electrical energy by the thermoelectric conversion module and fed into the power supply network.

[0025] The core invention of this embodiment lies in the dynamic energy storage potential prediction model and multi-objective rolling optimization algorithm built into the controller. The model expression is: ; In this embodiment, Take 0.85, Take 0.92, The timeframe is 15 minutes. The model calculates the stored energy potential for the next 15 minutes in real time, providing a basis for optimization.

[0026] The objective function of the algorithm executed by the optimization computing engine is: ; Among them, the prediction time domain (i.e., the next hour) Dynamically adjusted by fuzzy logic rules: Increased when load forecast fluctuates drastically. Increase when energy storage level is too low The solution employs a sequential quadratic programming algorithm, generating control commands including: whether the photovoltaic unit operates at reduced power, the heating power of the electric heating element, and the opening degree of the reactor exhaust valve (controlling the hydrogen release rate, thereby controlling the heat release rate).

[0027] Example 2 This embodiment describes a solar energy storage method, utilizing the system of Embodiment 1, such as... Figure 4 The flowchart is shown below: Step S1: Power on and initialize the thermo-electric co-predictive controller, and collect the current photovoltaic output power, reactor internal temperature (320℃), pressure (2MPa) and phase change buffer layer temperature (380℃).

[0028] Step S2: Obtain the irradiance forecast sequence for the next 4 hours from the meteorological bureau API via the communication interface module (one point every 15 minutes), and obtain the load forecast sequence from the user's smart meter.

[0029] Step S3: Optimize the computational engine's predictive control algorithm. Assume a forecast indicates cloud cover will appear in the next 30 minutes, reducing irradiance by 40%, while load is predicted to increase. The algorithm derives the optimal instruction: within the current cycle (0-15 minutes), instruct the photovoltaic unit to use maximum power tracking, but convert 30% of its electrical energy into heat energy through heating elements, prematurely driving the decomposition of MgH2 to store hydrogen heat, raising the reactor's internal temperature from 350℃ to 380℃ (utilizing the phase change buffer layer to absorb peak heat flux). The objective function J is minimized under this instruction.

[0030] Step S4: The photovoltaic unit executes the first type of instruction, outputting 100% of the maximum available power, but redistributes it through the power distribution unit.

[0031] Step S5: The thermochemical energy storage reactor executes the second type of instruction: the heating element is started at 500W power, the exhaust valve is closed, and the reaction proceeds in the endothermic direction.

[0032] Step S6: After 15 minutes, the controller updates the actual status: the irradiance has decreased, but the reactor temperature remains at 370°C, and the phase change buffer layer begins to release heat. The controller rolls the predicted time domain forward by one step and repeats the optimization. At this point, a new instruction requires the thermochemical energy storage reactor to begin a reverse exothermic reaction. The released hydrogen reacts with Mg to generate MgH2, and the released heat generates electricity through a heat exchanger to compensate for the power deficit of the photovoltaic unit.

[0033] Through the above cycle, the system achieves proactive pre-compensation for future energy fluctuations, rather than passive response.

[0034] Example 3 Based on Example 1, this embodiment further specifies that the reversible thermochemical reaction is calcium carbonate ( Decomposition / synthesis reactions of ) At this point, the system also includes a CO2 storage tank connected to the outlet of the thermochemical energy storage reactor. (Optimization algorithm) The molar reaction enthalpy of calcium carbonate decomposition was adjusted accordingly (approximately 178 kJ / mol). The phase change material of the phase change buffer layer was replaced with a sodium carbonate-potassium carbonate binary molten salt, whose phase change temperature matches the decomposition temperature of calcium carbonate (approximately 850-900℃). The remaining structure and connection relationships are the same as in Example 1, and will not be repeated here.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A solar frequency-division energy storage system based on potential energy prediction, characterized in that, include: A spectrum divider receives solar radiation at its input and splits the solar radiation into a first band of light and a second band of light for output. A photovoltaic unit, whose light incident surface is optically coupled to the first band light output end of the spectral frequency divider, is used to convert the first band light into electrical energy. A thermochemical energy storage reactor, the heat absorption surface of which is optically coupled to the second band light output end of the spectral frequency divider, the interior of which is filled with an energy storage medium for reversible thermochemical reactions; A phase change buffer layer is tightly wrapped around the outer wall of the thermochemical energy storage reactor to suppress transient temperature fluctuations inside the reactor. A smart thermo-electric co-regulator is electrically connected to the output terminal of the photovoltaic unit, the state monitoring terminal of the thermochemical energy storage reactor, and an external energy management bus, respectively. The intelligent thermoelectric co-regulator incorporates a dynamic energy storage potential prediction model. This model executes a multi-objective rolling optimization algorithm based on real-time collected irradiance sequences, real-time output power sequences of the photovoltaic unit, reaction progress sequences inside the thermochemical energy storage reactor, and user-side load prediction sequences to generate a set of optimal control commands. These optimal control commands are used to dynamically allocate, in the next control cycle, whether the electrical energy output by the photovoltaic unit is directly supplied to the load, stored in the electrical energy storage device, or converted into heat energy through an electrothermal element to supplement the thermochemical energy storage reactor, and to dynamically adjust the forward endothermic reaction rate or reverse exothermic reaction rate of the thermochemical energy storage reactor.

2. The system according to claim 1, characterized in that, The mathematical expression for the dynamic energy storage potential prediction model is as follows: ； in, The total energy storage potential of the system in the next time period is predicted. To predict irradiance, This represents the actual output power of the photovoltaic unit. This represents the real-time reaction conversion rate of the thermochemical energy storage reactor. This is the real-time molar enthalpy of reaction for this reversible thermochemical reaction. These are the weighting coefficients.

3. The system according to claim 1, characterized in that, The objective function of this multi-objective rolling optimization algorithm is: ； in, To predict load, This represents the total power supply of the system. For the target energy storage state, This represents the actual energy storage state. For energy conversion loss, As a dynamic weighting factor, To predict the length of the time domain.

4. The system according to claim 1, characterized in that, This intelligent thermo-electric synergistic regulator includes: An environmental sensing module is used to collect meteorological data, including solar irradiance, ambient temperature, and wind speed. A state monitoring module is used to collect the output voltage / current of the photovoltaic unit, the temperature and pressure inside the thermochemical energy storage reactor, and the temperature of the phase change buffer layer; A communication interface module is used to acquire user-side load forecast data; An optimization computing engine is used to run the dynamic energy storage potential prediction model and the multi-objective rolling optimization algorithm, and output the optimal control command.

5. The system according to claim 1, characterized in that, It also includes a power distribution unit connected to the intelligent thermo-electric co-regulator, which has multiple output ports connected to the user load, the battery pack and the electrothermal element embedded in the thermochemical energy storage reactor.

6. A method for solar energy storage using the system described in any one of claims 1 to 5, characterized in that, Includes the following steps: Step S1: The thermoelectric co-predictive controller initializes the dynamic energy storage potential prediction model and collects the current state parameters of the system; Step S2: The thermal-electric co-predictive controller obtains the predicted irradiance sequence and predicted load sequence for the next prediction time domain through the environmental sensing module and the communication interface module; Step S3: The optimization calculation engine of the thermo-electric co-predictive controller aims to minimize the objective function of the multi-objective rolling optimization algorithm, solves the problem within the constraints, and generates the coordinated action command for the photovoltaic unit and the thermochemical energy storage reactor in the next control cycle. Step S4: The photovoltaic unit determines its maximum power point tracking mode or power limiting mode according to the first type of instruction; Step S5: The thermochemical energy storage reactor controls its endothermic or exothermic reaction rate by adjusting the valve opening, the power of the electric heating element, or the flow rate of the circulating pump according to the second type of instruction. Step S6: At the end of each control cycle, the thermo-electric co-predictive controller updates the state observations and rolls the prediction time domain forward by one step, repeating steps S3 to S5.

7. The method according to claim 6, characterized in that, The constraints in step S3 include: the reaction temperature of the thermochemical energy storage reactor does not exceed the upper limit of the temperature resistance of the thermochemical energy storage reactor, the reaction conversion rate of the energy storage medium does not exceed the limiting conversion rate of the energy storage medium, and the output power of the photovoltaic unit does not exceed the maximum usable power of the photovoltaic unit.

8. The method according to claim 6, characterized in that, The reversible thermochemical reaction is a hydrogenation / dehydrogenation reaction of metal hydrides, a decomposition / synthesis reaction of metal carbonates, or a dehydration / hydration reaction of metal hydroxides.

9. The method according to claim 6, characterized in that, In step S2, the length of the prediction time domain is 4 to 12 control cycles, and the duration of each control cycle is 5 to 30 minutes.

10. The method according to claim 6, characterized in that, In step S5, when the optimal control command requires the thermochemical energy storage reactor to perform a reverse exothermic reaction, the released heat is converted into electrical energy through a thermoelectric conversion module thermally coupled to the thermochemical energy storage reactor, and then fed into the power supply network via the power distribution unit.

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