Photovoltaic hydrogen storage system and its power control method, device and readable storage medium

Abstract

This application relates to a photovoltaic hydrogen storage system and its power control method, apparatus, and readable storage medium. The method includes: predicting the future photovoltaic power generation of the photovoltaic module in a future time period, where the future time period is from the current daytime power generation cycle to the end of the daytime power generation cycle; determining the average battery power that the electrolyzer can obtain in the future time period based on the output battery capacity of the energy storage battery in the current daytime power generation cycle; determining the total average power that the electrolyzer can obtain in the future time period based on the future photovoltaic power generation and the output battery capacity; determining the operable power of the electrolyzer in the current daytime power generation cycle based on the average battery power, the total average power, and the actual photovoltaic power output to the DC converter by the photovoltaic module in the current daytime power generation cycle; and controlling the DC converter to output the operable power to the electrolyzer based on loop control principles. This method can reduce the risk of repeated start-ups and shutdowns of the electrolyzer.

Description

Technical Field

[0001] This application relates to the field of photohydrogen storage technology, and in particular to a photohydrogen storage system and its power control method, apparatus and readable storage medium. Background Technology

[0002] Hydrogen energy is a widely available, clean, low-carbon, flexible, efficient, and versatile secondary energy source. One technological route for photovoltaic hydrogen storage involves using the electricity generated by photovoltaics to electrolyze water and produce hydrogen, thereby achieving zero carbon emissions.

[0003] In photovoltaic hydrogen storage systems, in addition to photovoltaic power generation modules and water electrolysis hydrogen production terminals, energy storage batteries can also be installed as energy buffer components. However, when there are fluctuations in sunlight and the energy storage batteries have a low state of charge, the electrolyzer is at risk of repeated start-ups and shutdowns. Repeated start-ups and shutdowns of the electrolyzer will cause efficiency losses and equipment aging, accelerating its lifespan degradation rate. Summary of the Invention

[0004] Therefore, it is necessary to address the above-mentioned technical problems by providing a photohydrogen storage system and its power control method, device, and readable storage medium that can reduce the risk of repeated start-up and shutdown of the electrolyzer, and slow down the life decay rate of the electrolyzer in the photohydrogen storage system.

[0005] In a first aspect, this application provides a power control method for a photovoltaic hydrogen storage system. The photovoltaic hydrogen storage system includes a DC-DC converter, and a photovoltaic module, an electrolyzer, and a storage battery, all electrically connected to the DC-DC converter. The method includes:

[0006] Predict the future photovoltaic power generation of the photovoltaic module in a future time period, where the future time period is the period from the current daytime power generation cycle to the end of the daytime power generation cycle;

[0007] Based on the output battery capacity of the energy storage battery during the current daytime power generation cycle, determine the average battery power that the electrolyzer can obtain in the future time period.

[0008] Based on the future photovoltaic power generation and the output battery power, determine the total average power that the electrolyzer can obtain in the future time period;

[0009] Based on the available average battery power, the available total average power, and the actual photovoltaic power output by the photovoltaic module to the DC converter during the current daytime power generation cycle, the operable power of the electrolyzer during the current daytime power generation cycle is determined.

[0010] Based on the loop control principle, the DC converter is controlled to output the operable power to the electrolytic cell.

[0011] In one embodiment, predicting the future photovoltaic power generation of the photovoltaic module over a future time period includes:

[0012] The predicted photovoltaic power for the current daytime power generation cycle is determined based on the solar radiation intensity, ambient temperature, and wind speed of the current daytime power generation cycle.

[0013] The predicted photovoltaic power is calculated by multiplying the predicted photovoltaic power by the duration of the current daytime power generation cycle, and the predicted power generation of the current daytime power generation cycle is obtained.

[0014] The predicted power generation of each power generation cycle within the future time period is accumulated to obtain the future photovoltaic power generation.

[0015] In one embodiment, determining the average available battery power of the electrolyzer in the future time period based on the output battery capacity of the energy storage battery in the current daytime power generation cycle includes:

[0016] Based on the state of charge and health of the energy storage battery during the current daytime power generation cycle, the output capacity of the energy storage battery is estimated.

[0017] Based on the duration of the current daytime power generation cycle, the number of cycles between the current daytime power generation cycle and the daytime power generation termination cycle, and the output battery capacity, the average battery power available for the future time period is determined.

[0018] In one embodiment, determining the total average power available to the electrolyzer in the future time period based on the future photovoltaic power generation and the output battery capacity includes:

[0019] The total future available power is obtained by summing the future photovoltaic power generation and the output battery power.

[0020] Based on the duration of the current daytime power generation cycle, the number of cycles between the current daytime power generation cycle and the daytime power generation termination cycle, and the total future available power, the total average power available for the future time period is determined.

[0021] In one embodiment, determining the operable power of the electrolyzer during the current daytime power generation cycle based on the available average battery power, the available total average power, and the actual photovoltaic power output to the DC-DC converter by the photovoltaic module during the current daytime power generation cycle includes:

[0022] If the average power of the available battery is less than or equal to the total average power available, and the low power threshold of the electrolyzer is less than the rated power of the electrolyzer, then the operable power of the electrolyzer in the current daytime power generation cycle is determined to be 0.

[0023] If the average power of the available battery is less than the low power threshold of the electrolyzer and the total average power of the available battery is less than the rated power of the electrolyzer, the operable power of the electrolyzer in the current daytime power generation cycle is determined based on the actual photovoltaic power of the photovoltaic module in the current daytime power generation cycle and the low power threshold of the electrolyzer.

[0024] If the average power of the battery is less than the low power threshold of the electrolyzer, the rated power of the electrolyzer is less than or equal to the total average power, the operable power of the electrolyzer in the current daytime power generation cycle is determined based on the actual photovoltaic power of the photovoltaic module and the low power threshold of the electrolyzer in the current daytime power generation cycle.

[0025] If the low power threshold of the electrolyzer is less than or equal to the average power of the available cells, and less than the rated power of the electrolyzer, the operable power of the electrolyzer in the current daytime power generation cycle is determined based on the actual photovoltaic power of the photovoltaic modules in the current daytime power generation cycle and the low power threshold of the electrolyzer.

[0026] If the low threshold power of the electrolyzer is less than or equal to the average power of the available cells, and the rated power of the electrolyzer is less than or equal to the total average power of the available cells, the operable power of the electrolyzer in the current daytime power generation cycle is determined based on the actual photovoltaic power of the photovoltaic modules in the current daytime power generation cycle and the rated power of the electrolyzer.

[0027] If the electrolyzer power low threshold is less than the electrolyzer rated power, less than the average power of the available batteries, and less than the total average power of the available batteries, then the operable power of the electrolyzer in the current daytime power generation cycle is determined to be the electrolyzer rated power.

[0028] In one embodiment, determining the total average power available to the electrolyzer in the future time period based on the future photovoltaic power generation and the output battery capacity further includes:

[0029] Calculate the degree of deviation of the actual photovoltaic power from the power output during the current daytime power generation cycle;

[0030] Based on the power deviation degree of the current daytime power generation cycle and the preset deviation threshold, the power correction coefficient of the current daytime power generation cycle is determined;

[0031] The future photovoltaic power generation capacity of the current daytime power generation cycle is updated and corrected based on the power correction coefficient of the current daytime power generation cycle.

[0032] In one embodiment, calculating the degree of power deviation of the actual photovoltaic power in the current daytime power generation cycle includes:

[0033] The predicted photovoltaic power over the historical daytime power generation cycles is summed to obtain the first total photovoltaic power value;

[0034] The summation of the actual photovoltaic power within the historical daytime power generation cycle yields the second total photovoltaic power value.

[0035] The power difference is obtained based on the difference between the first total photovoltaic power and the second total photovoltaic power.

[0036] The degree of power deviation in the current daytime power generation cycle is obtained based on the ratio of the power difference to the total second photovoltaic power.

[0037] In one embodiment, the preset deviation threshold includes a preset negative deviation threshold and a preset positive deviation threshold. Determining the power correction coefficient for the current daytime power generation cycle based on the power deviation degree of the current daytime power generation cycle and the preset deviation threshold includes:

[0038] If the power deviation is less than the preset negative deviation threshold, the power correction factor for the current daytime power generation cycle is determined to be the sum of the power correction factor for the previous daytime power generation cycle and the power deviation.

[0039] If the power deviation is greater than or equal to the negative deviation threshold and less than or equal to the preset positive deviation threshold, the power correction factor of the current daytime power generation cycle is determined to be the power correction factor of the previous daytime power generation cycle.

[0040] If the power deviation is greater than the preset positive deviation threshold, the power correction factor for the current daytime power generation cycle is determined to be the difference between the power correction factor for the previous daytime power generation cycle and the power deviation.

[0041] In one embodiment, the output terminal of the DC-DC converter is the port where the DC-DC converter connects to the electrolytic cell. The step of controlling the DC-DC converter to output the operable power to the electrolytic cell based on the loop control principle includes:

[0042] Based on the PI loop control principle, the set reference voltage, and the output voltage of the DC converter sampled during the current daytime power generation cycle, the first reference current of the current daytime power generation cycle is determined.

[0043] Based on the operable power of the current daytime power generation cycle and the output voltage within the current daytime power generation cycle, a second reference current for the current daytime power generation cycle is determined;

[0044] The target current is determined based on the first reference current and the second reference current;

[0045] Based on the target current, the output current of the output terminal sampled during the current daytime power generation cycle, and the PI loop control principle, the duty cycle of the switching transistor of the DC-DC converter is determined.

[0046] In one embodiment, determining the duty cycle of the switching transistor of the DC-DC converter based on the target current, the output current sampled during the current daytime power generation cycle, and the PI loop control principle includes:

[0047] The target current is gradually varied based on a preset slope value to obtain a third reference current.

[0048] Based on the third reference current, the output current of the output terminal sampled during the current daytime power generation cycle, and the PI loop control principle, the duty cycle of the switching transistor of the DC-DC converter is determined.

[0049] Secondly, this application also provides a power control device for a photovoltaic hydrogen storage system. The photovoltaic hydrogen storage system includes a DC converter, and a photovoltaic module, an electrolyzer, and a storage battery, all electrically connected to the DC converter. The device includes:

[0050] A photovoltaic power generation prediction module is used to predict the future photovoltaic power generation of the photovoltaic module in a future time period, wherein the future time period is the period from the current daytime power generation cycle to the end of the daytime power generation cycle;

[0051] The battery average power determination module is used to determine the average battery power that the electrolyzer can obtain in the future time period based on the output battery power of the energy storage battery in the current daytime power generation cycle.

[0052] The total average power determination module is used to determine the total average power that the electrolyzer can obtain in the future time period based on the future photovoltaic power generation and the output battery power.

[0053] An operable power determination module is used to determine the operable power of the electrolyzer for the current daytime power generation cycle based on the available average battery power, the available total average power, and the actual photovoltaic power output by the photovoltaic module to the DC converter during the current daytime power generation cycle.

[0054] An electrolytic cell power control module is used to control the DC-DC converter to output the operable power to the electrolytic cell based on the loop control principle.

[0055] Thirdly, this application also provides a photovoltaic hydrogen storage system, including a DC converter, and a photovoltaic module, an electrolyzer, and a storage battery respectively electrically connected to the DC converter, wherein the photovoltaic hydrogen storage system performs power control using the steps described above.

[0056] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, performs the steps described above.

[0057] The aforementioned photovoltaic hydrogen storage system and its power control method, apparatus, and readable storage medium include a DC-DC converter, a photovoltaic module, an electrolyzer, and an energy storage battery electrically connected to the DC-DC converter. The obtainable average battery power represents the average power that the energy storage battery can supply to the electrolyzer in the future time period, and the obtainable total average power represents the average power that the photovoltaic module and the energy storage battery can jointly supply to the electrolyzer in the future time period. Using the obtainable average battery power, the obtainable total average power, and the actual photovoltaic power as the basis for determining the operable power of the current daytime power generation cycle can fully consider the power supply situation of the photovoltaic module and the energy storage battery in the future time period, dynamically adjust the operable power of the current daytime power generation cycle, achieve a smooth change in the daytime electrolyzer power, reduce the risk of frequent start-up and shutdown of the electrolyzer, and, since the actual photovoltaic power is taken into account, it can also accommodate the prediction error of future photovoltaic power generation to a certain extent. Attached Figure Description

[0058] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0059] Figure 1 This is a schematic diagram of the architecture of a photovoltaic hydrogen storage system in one embodiment;

[0060] Figure 2 This is a flowchart illustrating the power control method of a photovoltaic hydrogen storage system in one embodiment;

[0061] Figure 3 This is a flowchart illustrating steps 302 to 306 in one embodiment;

[0062] Figure 4 This is a flowchart illustrating steps 402 to 404 in one embodiment;

[0063] Figure 5 This is a flowchart illustrating steps 502 to 504 in one embodiment;

[0064] Figure 6 The graph shows the changes in electrolyzer power and SOC of the energy storage battery in the photovoltaic hydrogen storage system in related technologies.

[0065] Figure 7 This is a graph showing the changes in electrolyzer power and SOC of the energy storage battery in a photovoltaic hydrogen storage system in one embodiment.

[0066] Figure 8 This is a graph showing the changes in electrolyzer power and SOC of the energy storage battery in another embodiment of the photohydrogen storage system;

[0067] Figure 9 This is a graph showing the changes in electrolyzer power and SOC of the energy storage battery in another embodiment of the photohydrogen storage system;

[0068] Figure 10 This is a flowchart illustrating steps 1002 to 1006 in one embodiment;

[0069] Figure 11 This is a graph showing the changes in electrolyzer power and SOC of the energy storage battery in another embodiment of the photohydrogen storage system;

[0070] Figure 12 This is a flowchart illustrating the power control method for a photovoltaic hydrogen storage system in another embodiment;

[0071] Figure 13 This is a flowchart illustrating steps 1302 to 1308 in one embodiment;

[0072] Figure 14 This is a circuit diagram of a photoelectric hydrogen storage system in one embodiment;

[0073] Figure 15 Here is a control loop diagram of a photovoltaic hydrogen storage system in one embodiment;

[0074] Figure 16 This is a schematic diagram of current change during current gradual change processing in one embodiment;

[0075] Figure 17 This is a structural block diagram of the power control device for a photovoltaic hydrogen storage system in one embodiment.

[0076] The reference numerals are as follows: 110, DC-DC converter; 120, photovoltaic module; 130, electrolytic cell; 140, energy storage battery. Detailed Implementation

[0077] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0078] It should be noted that the terms "first," "second," etc., used in this application can be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from the second element. The terms "comprising" and "having," and any variations thereof, used in this application, are intended to cover non-exclusive inclusion. The term "multiple" used in this application refers to two or more. The term "and / or" used in this application refers to one of the embodiments, or any combination of multiple embodiments.

[0079] Typical operating scenarios for photovoltaic-hydrogen storage systems include abundant sunlight, fluctuating sunlight, and scarce sunlight. In scenarios with abundant sunlight, the photovoltaic modules can generate electricity at full capacity, simultaneously charging both the electrolyzer and the energy storage battery, enabling the electrolyzer to efficiently produce hydrogen. In scenarios with fluctuating sunlight, if the photovoltaic power suddenly drops, the energy storage battery can instantly discharge to make up the shortfall, maintaining stable electrolyzer power and ensuring uninterrupted hydrogen production. In scenarios with scarce sunlight (e.g., at night or during cloudy / rainy weather), the photovoltaic modules stop generating electricity, the energy storage battery discharges to its minimum threshold, the electrolyzer shuts down, and automatically restarts once sunlight returns.

[0080] In scenarios with fluctuating sunlight, if the state of charge (SOC) of the energy storage battery falls below the safety threshold, the electrolyzer faces the potential risk of repeated start-ups and shutdowns. This risk stems from the disruption of the power balance in the photovoltaic hydrogen storage system: a sudden drop in photovoltaic power combined with insufficient available battery energy causes the electrolyzer's input power to repeatedly fall below its minimum operating load (typically 20%-40% of rated power), triggering a protective shutdown. When sunlight recovers and the startup threshold is reached again, the system restarts, forming a start-stop cycle.

[0081] Repeated start-ups and shutdowns of electrolyzers cause efficiency losses and equipment aging. Each start-up and shutdown requires additional energy for preheating or pressurization (cold start efficiency loss reaches 15%-30%), and hydrogen production efficiency decreases during low-load operation. Repeated thermal cycles lead to mechanical stress fatigue of the electrolyzer membrane electrodes, catalyst layer peeling, and the life decay rate can be more than twice that of continuous operation.

[0082] The power control method for a photovoltaic hydrogen storage system provided in this application embodiment can be applied to, for example... Figure 1 The photovoltaic hydrogen storage system shown includes a DC-DC converter 110, a photovoltaic module 120, an electrolyzer 130, and a storage battery 140, all electrically connected to the DC-DC converter 110.

[0083] Figure 1The arrows in the diagram indicate the direction of energy flow. The photovoltaic module 120, as the system's energy source, converts solar energy into electrical energy, which is then output to the DC-DC converter 110. Its output power dynamically changes with the light intensity. The DC-DC converter 110, as an energy dispatching component, can dynamically adjust impedance matching through the MPPT (Maximum Power Point Tracking) algorithm to maximize photovoltaic power generation efficiency and convert the photovoltaic input into stable DC power required by the electrolyzer 130 and energy storage battery 140. The energy storage battery 140, as an energy buffer component, can instantaneously discharge to compensate for power gaps when photovoltaic power changes abruptly, maintaining the continuous operation of the electrolyzer 130; when there is excess sunlight, it can store surplus electrical energy to prevent wasted solar power. The electrolyzer 130, as a hydrogen production terminal, can receive stable electrical energy from the DC-DC converter 110 to drive the electrolysis of water to produce hydrogen, which can be supplied to other industries.

[0084] In one exemplary embodiment, such as Figure 2 As shown, a power control method for a photovoltaic hydrogen storage system is provided, which can be applied to... Figure 1 The following steps are used as an example of a photovoltaic hydrogen storage system, including steps 202 to 210.

[0085] Step 202: Predict the future photovoltaic power generation of the photovoltaic module in a future time period, which is the period from the current daytime power generation cycle to the end of the daytime power generation cycle.

[0086] Future photovoltaic (PV) power generation capacity refers to the predicted amount of electricity that PV modules can generate from the current daytime power generation cycle to the end of the daytime power generation cycle. Both the current daytime power generation cycle and the end of the daytime power generation cycle can be considered as time periods within the daytime PV power generation capacity. It is understood that PV modules generate electricity during the daytime when there is sunlight; therefore, the daytime PV power generation capacity period can be pre-set based on the geographical location of the PV modules and the date.

[0087] For example, the daytime photovoltaic power generation period is determined to be from Ts to Te (e.g., from 6:00 to 18:00). The daytime photovoltaic power generation period is divided into N time periods according to a fixed interval length Δt. Each time period is represented by a sequence number from 0 to N. Then, the sequence number 0 represents the start period of daytime power generation, the sequence number k represents the kth daytime power generation period, and the sequence number N represents the end period of daytime power generation.

[0088] For example, photovoltaic (PV) power generation parameters for a future time period are obtained and input into a PV power prediction model to obtain the future PV power generation. PV power generation parameters include various types of data that affect PV power generation, such as irradiance and the light-receiving area of ​​PV modules.

[0089] Step 204: Determine the average battery power that the electrolyzer can obtain in the future time period based on the output battery power of the energy storage battery in the current daytime power generation cycle.

[0090] Output battery capacity refers to the amount of electricity that the energy storage battery can supply to the electrolyzer during the current daytime power generation cycle. Available average battery power refers to the average power that the energy storage battery can supply to the electrolyzer over a future period.

[0091] For example, the output battery capacity is determined based on the battery state parameters of the energy storage battery BMS (Battery Management System), and the average power of the available battery is calculated based on the output battery capacity and the duration of the future time period.

[0092] Step 206: Determine the total average power that the electrolyzer can obtain in the future time period based on the future photovoltaic power generation and the output battery power.

[0093] The total available average power refers to the average total power that photovoltaic modules and energy storage batteries can supply to the electrolyzer over a future period.

[0094] For example, the total available power to be supplied to the electrolyzer is determined based on the future photovoltaic power generation and the output battery power, and the total average power that can be obtained is calculated based on the total available power.

[0095] Step 208: Based on the available average battery power, the available total average power, and the actual photovoltaic power output to the DC converter by the photovoltaic modules during the current daytime power generation cycle, determine the operable power of the electrolyzer during the current daytime power generation cycle.

[0096] Actual photovoltaic power refers to the actual power output of the photovoltaic modules to the DC-DC converter. Actual photovoltaic power reflects the true state of photovoltaic module power generation. When the average power of the available cells and the total average power available are used as the basis for determining the operable power of the electrolyzer, including actual photovoltaic power in the determination can increase the consideration of the true state and, to a certain extent, accommodate the prediction error in the total average power available.

[0097] For example, the future operating state of the electrolyzer is determined based on the available average battery power and the available total average power, and the operable power of the electrolyzer in the current daytime power generation cycle is determined based on the future operating state and the actual photovoltaic power output to the DC converter by the photovoltaic modules in the current daytime power generation cycle.

[0098] Step 210: Based on the loop control principle, control the DC converter to output operating power to the electrolytic cell.

[0099] The loop control principle refers to the control principle in which an error signal is generated by feedback of the output quantity in a closed loop, and the physical quantities in the circuit are adjusted according to the error signal.

[0100] For example, based on the loop control principle, the voltage and current output of the DC converter to the electrolytic cell are set according to the operable power, and the DC converter is controlled to output operable power to the electrolytic cell.

[0101] In the aforementioned power control method for a photovoltaic-hydrogen storage system, the average power of the available batteries can represent the average power that the energy storage batteries can supply to the electrolyzer in the future, and the total average power available can represent the average power that the photovoltaic modules and energy storage batteries can jointly supply to the electrolyzer in the future. By using the average power of the available batteries, the total average power available, and the actual photovoltaic power together as the basis for determining the operable power of the current daytime power generation cycle, the power supply situation of the photovoltaic modules and energy storage batteries in the future can be fully considered, and the operable power of the current daytime power generation cycle can be dynamically adjusted to achieve a smooth change in the power of the electrolyzer during the daytime, reduce the risk of frequent start-up and shutdown of the electrolyzer, and, since the actual photovoltaic power is taken into account, it can also accommodate the prediction error of the future photovoltaic power generation to a certain extent.

[0102] In one exemplary embodiment, such as Figure 3 As shown, step 202 includes steps 302 to 306.

[0103] Step 302: Determine the predicted photovoltaic power for the current daytime power generation cycle based on the solar radiation intensity, ambient temperature, and wind speed of the current daytime power generation cycle.

[0104] It is understandable that meteorological data such as solar radiation intensity, ambient temperature, and wind speed affect the power generation of photovoltaic modules, and these data change over time. During the current daytime power generation cycle, meteorological data can be obtained in real time to calculate and predict photovoltaic power.

[0105] For example, the predicted photovoltaic power for the current daytime power generation cycle is determined by referring to the following formula (1).

[0106]

[0107] Where k represents any diurnal power generation cycle, P pvpre To predict photovoltaic power, η r η represents the photoelectric conversion efficiency (ranging from 0.15 to 0.22). d For DC conversion efficiency, A m For the area of ​​photovoltaic modules, G s (k) represents the solar radiation intensity corresponding to the kth daytime power generation cycle, α is the temperature coefficient (ranging from 0.3% to 0.5% / ℃), and T a(k) represents the ambient temperature corresponding to the kth daytime power generation cycle, V w (k) represents the wind speed corresponding to the kth daytime power generation cycle. G s (k) T a (k) and V w (k) can all be obtained in real time through meteorological data; photoelectric conversion efficiency η r Photovoltaic module area A m The temperature coefficient α can be determined based on the characteristics of the photovoltaic module. DC conversion efficiency η d It can be determined based on the performance of the DC-DC converter.

[0108] in, This can be understood as the temperature of the photovoltaic module.

[0109] For example, by referring to the calculation method of the predicted photovoltaic power of the current daytime power generation cycle, the predicted photovoltaic power of each daytime power generation cycle within the daytime photovoltaic power generation period can be determined, and the actual photovoltaic power of the photovoltaic module can be recorded in each daytime power generation cycle, as shown in Table 1 below.

[0110] Table 1

[0111]

[0112] Step 304: Calculate the product of the predicted photovoltaic power and the duration of the current daytime power generation cycle to obtain the predicted power generation of the current daytime power generation cycle.

[0113] The predicted photovoltaic power can be used as the average power during the current daytime power generation cycle. Therefore, the predicted photovoltaic power is multiplied by the duration of the current daytime power generation cycle, and the product is the predicted power generation for the current daytime power generation cycle.

[0114] Step 306: Accumulate the predicted power generation of each power generation cycle within the future time period to obtain the future photovoltaic power generation.

[0115] By referring to the calculation method of the predicted power generation of the current daytime power generation cycle, the predicted power generation of each power generation cycle in the future time period can be calculated. By adding these predicted power generation values ​​together, the future photovoltaic power generation can be obtained.

[0116] For example, the future photovoltaic power generation can be calculated with reference to the following formula (2).

[0117]

[0118] Where i represents the current daytime power generation cycle, N represents the daytime power generation termination cycle, and Q pvpre [i,N] represents the future photovoltaic power generation capacity over the time period from the current daytime power generation cycle i to the end of the daytime power generation cycle N.s [i] represents the solar radiation intensity during the current daytime power generation cycle, T a [i] represents the ambient temperature during the current daytime power generation cycle, V w [i] represents the wind speed of the current daytime power generation cycle, and Δt represents the interval between two adjacent daytime power generation cycles.

[0119] As time goes on, the value of the current daytime power generation cycle i can vary from 0 to N, and is updated according to the actual daytime time. Solar radiation intensity, ambient temperature, and wind speed may also change.

[0120] In this embodiment, the predicted power generation of the current daytime power generation cycle is determined by meteorological data, and then the future photovoltaic power generation is obtained. The future photovoltaic power generation can be updated over time to improve the accuracy of the prediction of future photovoltaic power generation.

[0121] In one exemplary embodiment, such as Figure 4 As shown, step 204: Based on the output battery power of the energy storage battery in the current daytime power generation cycle, determine the average battery power that the electrolyzer can obtain in the future time period, which may include steps 402 to 404.

[0122] Step 402: Estimate the output capacity of the energy storage battery based on the battery charge state and battery health state of the energy storage battery during the current daytime power generation cycle.

[0123] Battery state of charge (SOH) represents the percentage of a battery's current remaining capacity relative to its total capacity when fully charged. Battery state of health (SOH) describes the degree of aging or degradation of a battery and can be calculated as the ratio of the battery's current usable capacity to its rated capacity.

[0124] For example, the output battery capacity of the energy storage battery is estimated using the following formula (3).

[0125]

[0126] Among them, Q bat [k] represents the output battery capacity in the kth daytime power generation cycle, SOC[k] represents the battery charge state in the kth daytime power generation cycle, SOH[k] represents the battery health state in the kth daytime power generation cycle, and the SOC low threshold is a preset safe value for the charge state of the energy storage battery. The value range of the SOC low threshold can be 10%-20%.

[0127] It is worth noting that SOC[k] represents the average battery charge capacity value during the k-th daytime power generation cycle, and SOH[k] is the average value of the battery health status value during the k-th daytime power generation cycle.

[0128] Step 404: Based on the duration of the current daytime power generation cycle, the number of cycles between the current daytime power generation cycle and the end of the daytime power generation cycle, and the output battery capacity, determine the average battery power available for future time periods.

[0129] Understandably, when the daytime power generation period is divided using a fixed interval Δt, the duration of future time periods can be calculated based on the length of the current daytime power generation cycle and the number of cycles between the current daytime power generation cycle and the end of the daytime power generation cycle. Based on the output battery capacity and the duration of future time periods, the average output power of the energy storage battery during those future time periods can then be calculated.

[0130] For example, the average power of the available battery can be calculated with reference to the following formula (4).

[0131]

[0132] Where i represents the current daytime power generation cycle, and N represents the daytime power generation termination cycle. P represents the number of cycles between the current daytime power generation cycle and the end of the daytime power generation cycle. ELB [i,N] represents the average available battery power over the future time period from the current daytime power generation cycle i to the daytime power generation termination cycle N.

[0133] In this embodiment, the average battery power available for future time periods can be updated over time, and the output battery power is estimated based on the battery charge state and battery health state, which are also updated in real time in different periods.

[0134] In one exemplary embodiment, such as Figure 5 As shown, step 206: Based on the future photovoltaic power generation and the output battery power, determine the total average power that the electrolyzer can obtain in the future time period, which may include steps 502 to 504.

[0135] Step 502: Sum the future photovoltaic power generation and the output battery power to obtain the total future available power.

[0136] Step 504: Based on the duration of the current daytime power generation cycle, the number of cycles between the current daytime power generation cycle and the end of the daytime power generation cycle, and the total available power in the future, determine the total average power available for the future time period.

[0137] The total available future electricity represents the total amount of electricity that can power the electrolyzers during the future period. The electricity sources for the electrolyzers include the electricity generated by the photovoltaic modules and the available electricity from the energy storage batteries; therefore, the total available future electricity can be obtained by summing these two sources.

[0138] For example, the total average power available for the electrolyzer in the future time period can be determined by referring to the following formula (5).

[0139]

[0140] Where i represents the current daytime power generation cycle, N represents the daytime power generation termination cycle, and P ELA [i,N] represents the total average power available for the future time period from the current daytime power generation cycle i to the daytime power generation termination cycle N.

[0141] In this embodiment, the calculated total average power available includes the predicted average photovoltaic power available. Both the total average power available and the average power available for cells are used as the basis for determining the operable power, which can be used to predict the future operating status of the electrolyzer and reasonably determine the operable power based on the predicted future operating status.

[0142] In one exemplary embodiment, the operable power P of the electrolyzer during the current daytime power generation cycle is determined based on the available average battery power, the available total average power, and the actual photovoltaic power output to the DC-DC converter by the photovoltaic modules during the current daytime power generation cycle. EL [i], which specifically includes the following 6 working conditions.

[0143] Operating Condition 1: Average battery power P can be obtained. ELB [i,N]≤The total average power P can be obtained ELA [i,N] < Electrolyzer power low threshold < Electrolyzer rated power.

[0144] The low power threshold of an electrolytic cell refers to the power threshold required to maintain its operating state. If the power input to the electrolytic cell falls below this threshold, a protective shutdown will be triggered. The rated power of the electrolytic cell refers to its designed operating power. Typically, an electrolytic cell operates best at its rated power. The low power threshold can range from 20% to 40% of the rated power; therefore, the statement "low power threshold < rated power" always holds true. Furthermore, based on the calculation method for the total average power, P... ELB [i,N]≤P ELA [i,N] also holds true, so the condition that the total average power can be obtained is less than the low power threshold of the electrolytic cell is satisfied, and the size relationship listed in the above working condition 1 exists.

[0145] Under operating condition 1, it can be predicted that both the future photovoltaic power generation and the output battery capacity of the energy storage battery will be low. The combined output of these two is insufficient to power the electrolyzer continuously at its low power threshold. The energy generated by the photovoltaic system should be used to charge the battery, and the electrolyzer should not be started temporarily. Determine the operable power P of the electrolyzer during the current daytime power generation cycle. EL[i] is 0, which can also be expressed as P. EL [i] = 0.

[0146] Operating Condition 2: Average battery power P can be obtained. ELB [i,N] < Low threshold of electrolytic cell power ≤ Obtainable total average power P ELA [i,N] < rated power of the electrolytic cell.

[0147] Under operating condition 2, it can be predicted that the output capacity of the energy storage battery is low, and the output capacity of the energy storage battery alone is insufficient to supply the electrolyzer to continue operating at the low power threshold of the electrolyzer. However, it is predicted that the future photovoltaic power generation and the output capacity of the energy storage battery can be added together to supply the electrolyzer to continue operating above the low power threshold of the electrolyzer. Therefore, the operating power can be determined based on the relationship between the actual photovoltaic power of the photovoltaic module and the low power threshold of the electrolyzer during the current daytime power generation cycle.

[0148] If the actual photovoltaic power P of the photovoltaic modules during the current daytime power generation cycle pvact [i] > Low power threshold, determine the operable power P of the electrolyzer in the current daytime power generation cycle. EL [i] represents the total available power, P EL [i] =P ELA [i,k]; If the actual photovoltaic power P of the photovoltaic module in the current daytime power generation cycle pvact [i]≤ power low threshold, determine the operable power P EL [i] is 0, P EL [i] = 0.

[0149] Operating Condition 3: Average battery power P can be obtained. ELB [i,N] < Electrolyte cell power low threshold < Electrolyte cell rated power ≤ Obtainable total average power P ELA [i,N].

[0150] Under operating condition 3, it can be predicted that the energy storage battery can output a low amount of battery power. The energy storage battery alone is insufficient to power the electrolyzer to continuously operate at the low power threshold. However, it is predicted that the future photovoltaic power generation and the energy storage battery can output battery power together can power the electrolyzer to continuously operate at the rated power. Therefore, the operating power can be determined based on the relationship between the actual photovoltaic power of the photovoltaic modules during the current daytime power generation cycle and the low power threshold of the electrolyzer.

[0151] If the actual photovoltaic power P pvact [i] > Low power threshold, determine the operable power P EL [i] represents the rated power of the electrolytic cell, P EL [i] = rated power of the electrolytic cell; if the actual photovoltaic power Ppvact [i]≤ power low threshold, determine the operable power P EL [i] is 0, P EL [i] = 0.

[0152] Operating Condition 4: Electrolyzer power low threshold ≤ average obtainable battery power P ELB [i,N]≤The total average power P can be obtained ELA [i,N] < rated power of the electrolytic cell.

[0153] Under operating condition 4, it can be predicted that the battery power output from the energy storage battery alone, or the sum of the future photovoltaic power generation and the battery power output from the energy storage battery, can supply the electrolyzer to continuously operate above the low power threshold of the electrolyzer. Therefore, the operable power can be determined based on the relationship between the actual photovoltaic power of the photovoltaic modules during the current daytime power generation cycle and the low power threshold of the electrolyzer.

[0154] If the actual photovoltaic power P pvact [k] > Low power threshold, determine the operable power P EL [i] represents the total available power, P EL [i] = P ELA [i,N]; if the actual photovoltaic power P pvact [k] ≤ power low threshold, determine the operable power P EL [i] represents the average power of the available battery, P EL [i] =P ELB [i,N].

[0155] Operating Condition 5: Electrolyzer power low threshold ≤ average obtainable battery power P ELB [i,N]< Electrolytic cell rated power≤ Obtainable total average power P ELA [i,N].

[0156] Under operating condition 5, it can be predicted that the energy storage battery alone can output enough battery power to supply the electrolyzer to operate continuously above the low threshold of the electrolyzer power. In the future, the photovoltaic power generation and the energy storage battery output can be added together to supply the electrolyzer to operate continuously at the electrolyzer's rated power. The excess energy generated by photovoltaic power generation charges the energy storage battery. Therefore, the operating power can be determined based on the relationship between the actual photovoltaic power of the photovoltaic modules and the rated power of the electrolyzer during the current daytime power generation cycle.

[0157] If the actual photovoltaic power P pvact [i] > Rated power, determine the operable power P EL [i] represents the rated power, P EL [i] = rated power of the electrolytic cell; if the actual photovoltaic power P pvact [i]≤ Rated power, determine the operable power PEL [i] represents the average power of the available battery, P EL [i] =P ELB [i,N].

[0158] Operating Condition 6: Electrolyzer power low threshold < Electrolyzer rated power ≤ Average power P of available battery ELB [i,N]≤The total average power P can be obtained ELA [i,N].

[0159] Under operating condition 6, it can be predicted that the energy storage battery alone can output battery power, or the future photovoltaic power generation can be predicted and the energy storage battery output can be added together. Both can supply the electrolyzer to continuously operate at the electrolyzer's rated power. The excess energy generated by photovoltaic power generation charges the energy storage battery, thus determining the operable power P. EL [i] represents the rated power of the electrolytic cell, P EL [i] = Rated power of the electrolytic cell.

[0160] In this embodiment, by judging the average power of the available battery, the total average power, the low threshold of the electrolyzer power, and the relationship between the rated power of the electrolyzer and the actual photovoltaic power, the operating condition of the electrolyzer in the future time period is predicted, so that the power of the electrolyzer can change smoothly during the daytime operation and can accommodate the error of photovoltaic prediction to a certain extent.

[0161] Figure 6 The graph shows the changes in electrolyzer power and SOC of the energy storage battery in the related photovoltaic hydrogen storage system, such as... Figure 6 As shown, after startup, the electrolyzer directly ramps up to its rated power. When the energy generated by photovoltaic power generation is insufficient, it relies on the energy storage battery to supply energy. When the SOC of the energy storage battery drops below the lower limit of the battery SOC, the electrolyzer shuts down, and the photovoltaic modules input energy to charge the energy storage battery. When the battery SOC is higher than the lower limit of the battery SOC, the energy storage battery outputs energy again, and the electrolyzer restarts. If the photovoltaic energy is still insufficient, the electrolyzer will shut down again after a period of time, resulting in repeated start-stop cycles of the electrolyzer.

[0162] Figure 7 and Figure 8 The graphs showing the changes in electrolyzer power and SOC of the energy storage battery in the two embodiments of this application are for comparison. Figure 6 , Figure 7 and Figure 8 It can be observed that when the initial SOC state of the energy storage battery, the actual photovoltaic power, and the predicted photovoltaic power are all similar, the power control method of the photovoltaic hydrogen storage system in this application will delay the start-up of the electrolyzer at the beginning of the daytime power generation period, resulting in a lower operating power than the previous method. Figure 6The power output is lower in the medium to low range, but the power variation is stable between 6:00 AM and 6:00 PM, without repeated start-ups and shutdowns. The power control method of this application embodiment has a certain tolerance for the prediction error of the photovoltaic module's predicted photovoltaic power. Even with a small prediction error, the electrolytic cell can still avoid repeated start-ups and shutdowns.

[0163] However, when the predicted photovoltaic power differs significantly from the actual photovoltaic power, it can still lead to frequent start-ups and shutdowns of the electrolyzer, such as... Figure 9 As shown.

[0164] Given the significant discrepancy between predicted and actual photovoltaic power, in one exemplary embodiment, such as... Figure 10 As shown, step 206 also includes steps 1002 to 1006.

[0165] Step 1002: Calculate the degree of power deviation of the actual photovoltaic power in the current daytime power generation cycle.

[0166] Power deviation refers to the degree of deviation between the actual photovoltaic power and the predicted photovoltaic power, and can characterize the prediction error between the predicted photovoltaic power and the actual value.

[0167] For example, the predicted photovoltaic power and actual photovoltaic power of the current daytime power generation cycle are obtained, the difference and sum between the predicted photovoltaic power and actual photovoltaic power of the current daytime power generation cycle are calculated, and the ratio of the difference and the sum is calculated to obtain the degree of power deviation of the current daytime power generation cycle.

[0168] For example, the predicted photovoltaic power within the historical daytime power generation cycle is summed to obtain the first total photovoltaic power value; the actual photovoltaic power within the historical daytime power generation cycle is summed to obtain the second total photovoltaic power value; the power difference is obtained based on the difference between the first total photovoltaic power value and the second total photovoltaic power value; and the power deviation in the current daytime power generation cycle is obtained based on the ratio of the power difference to the second total photovoltaic power value. The historical daytime power generation cycle refers to the power generation cycle preceding the current daytime power generation cycle, and the number of power generation cycles taken in the historical daytime power generation cycle can be arbitrarily selected. For example, the two adjacent power generation cycles of the current daytime power generation cycle can be taken as the historical daytime power generation cycle, and the power deviation can be calculated with reference to the following formula (6).

[0169]

[0170] Where D[i] represents the power deviation of the current daytime power generation cycle i, and P pvpre [i-1] represents the predicted photovoltaic power of the previous daytime power generation cycle i-1, where P is the current daytime power generation cycle i. pvpre [i-2] represents the predicted photovoltaic power of the two preceding daytime power generation cycles i-2 of the current daytime power generation cycle i, Ppvpre [i-1] and P pvpre [i-2] represents historical data for the current daytime power generation cycle i, i.e., predicted photovoltaic power data within the historical daytime power generation cycles of the current daytime power generation cycle i, P pvact [i-1] represents the actual photovoltaic power of the previous daytime power generation cycle i-1, where P is the current daytime power generation cycle i. pvact [i-2] represents the actual photovoltaic power of the two preceding daytime power generation cycles i-2 of the current daytime power generation cycle i.

[0171] Step 1004: Determine the power correction coefficient for the current daytime power generation cycle based on the power deviation degree of the current daytime power generation cycle and the preset deviation threshold.

[0172] The preset deviation threshold is a threshold used to determine the degree of power deviation. The power correction factor is a coefficient used to correct the available total average power. For example, the power correction factor for the current daytime power generation cycle is determined based on the relationship between the power deviation of the current daytime power generation cycle and the preset deviation threshold.

[0173] In an exemplary embodiment, the preset deviation threshold includes a preset negative deviation threshold and a preset positive deviation threshold. As can be seen from the above formula (6), the calculated value of the power deviation degree D[i] of the current daytime power generation cycle i may include positive, zero and negative values. The preset negative deviation threshold is a threshold with a negative value, and the preset positive deviation threshold is a threshold with a positive value.

[0174] If the power deviation is less than the preset negative deviation threshold, D[i] < the preset negative deviation threshold. The power correction coefficient of the current daytime power generation cycle can be determined by referring to the following formula (7), which is the sum of the power correction coefficient of the previous daytime power generation cycle and the power deviation.

[0175]

[0176] Where C[i] is the power correction coefficient for the current daytime power generation cycle, and C[i-1] is the power correction coefficient for the previous daytime power generation cycle.

[0177] When the power deviation is greater than or equal to the negative deviation threshold and less than or equal to the preset positive deviation threshold, the preset negative deviation threshold ≤ D[i] ≤ the preset positive deviation threshold. The power correction coefficient of the current daytime power generation cycle can be determined by referring to the following formula (8) as the power correction coefficient of the previous daytime power generation cycle.

[0178]

[0179] If the power deviation is greater than the preset positive deviation threshold, the preset positive deviation threshold < D[i]. The power correction coefficient of the current daytime power generation cycle can be determined by referring to the following formula (9), which is the difference between the power correction coefficient of the previous daytime power generation cycle and the power deviation.

[0180]

[0181] For example, the preset positive deviation threshold ranges from 2% to 5%, and the preset negative deviation threshold ranges from -5% to -2%.

[0182] In this embodiment, by setting an appropriate preset deviation threshold, the predicted photovoltaic power can be corrected in each power generation cycle, thereby reducing the impact of the error between the predicted photovoltaic power and the actual photovoltaic power on the total average power that can be obtained.

[0183] Step 1006: Update and correct the future photovoltaic power generation capacity of the current daytime power generation cycle based on the power correction coefficient of the current daytime power generation cycle.

[0184] For example, the future photovoltaic power generation Q during the current daytime power generation cycle pvpre [i,N] has been updated and corrected to: .

[0185] For example, regarding the photovoltaic power generation Q pvpre After correcting [i,N], the total average power P available to the electrolyzer in the future time period is... ELA [i,N] can be corrected, and the total average power P available to the electrolyzer in the future time period can be obtained by referring to the following formula (10). ELA [i,N].

[0186]

[0187] In this embodiment, by updating and correcting the future photovoltaic power generation, the electrolytic cell power can be kept stable when the predicted photovoltaic power deviates significantly from the actual photovoltaic power, thus avoiding frequent start-ups and shutdowns due to insufficient photovoltaic energy and improving the tolerance for prediction errors in the predicted photovoltaic power.

[0188] Figure 11 This is a graph showing the changes in electrolyzer power and SOC of the energy storage battery in another embodiment of the photovoltaic hydrogen storage system, for comparison. Figure 9 and Figure 11 It can be seen that by updating and correcting the future photovoltaic power generation capacity of the current daytime power generation cycle, the tolerance of the prediction error of photovoltaic power can be improved, the electrolyzer power can be made stable, and the frequent start-up and shutdown of photovoltaic power fluctuations can be avoided.

[0189] In one exemplary embodiment, such as Figure 12 As shown, in determining the operable power of the electrolyzer during the current daytime power generation cycle, the future photovoltaic power generation Q of the photovoltaic module is first predicted for future time periods. pvpre [i,N], calculate the output battery capacity Q of the energy storage battery during the current daytime power generation cycle. bat [i] can be determined based on the future photovoltaic power generation Q. pvpre [i,N] and the output battery capacity Q bat [i] can be directly calculated to determine the total average power available from the electrolyzer in the future time period. Alternatively, the power deviation D[i] and power correction coefficient C[i] of the actual photovoltaic power during the current daytime power generation cycle can be calculated. Based on the power correction coefficient C[i], the future photovoltaic power generation Q can be calculated. pvpre [i,N] is updated and corrected based on the updated and corrected future photovoltaic power generation Q. pvpre [i,N] Calculate the total average available power P of the electrolyzer in the future time period. ELA [i,N], calculate the average available battery power P of the electrolyzer in the future time period. ELB [i,N]. For the obtainable total average power P ELA [i,N] is compared with the low power threshold of the electrolyzer: if P ELA [i,N] < power low threshold, P EL [i]=0; otherwise, the average battery power P can be obtained. ELB [i,N] is compared with the low power threshold of the electrolyzer, if P ELB If [i,N] < power low threshold, then compare the actual photovoltaic power with the power low threshold. If P pvact If [i] ≥ power low threshold, then P EL [i]=P ELA [i,N], if P pvact [i] < power low threshold, then P EL [i]=0; if P ELB If [i,N] ≥ power low threshold, then compare the actual photovoltaic power with the power low threshold. If P pvact If [i] ≥ power low threshold, then P EL [i]=P ELA [i,N], if P pvact [i] < power low threshold, then P EL [i]=P ELB [i,N]. P EL [i]=P ELA [i,N] and P EL [i]=P ELB In the case of [i,N], P EL [i] are all within the range between the low power threshold and the rated power.

[0190] In one exemplary embodiment, the output terminal of the DC-DC converter is the port where the DC-DC converter connects to the electrolytic cell, such as... Figure 13 As shown, step 210 includes steps 1302 to 1308.

[0191] Step 1302: Based on the PI loop control principle, the set reference voltage, and the output voltage of the DC-DC converter sampled during the current daytime power generation cycle, determine the first reference current for the current daytime power generation cycle.

[0192] PI (Proportional Integral) loop control refers to a control method that adjusts parameters in the loop through proportional and integral control. The set reference voltage is the voltage set to control the input power of the electrolyzer; it can be set to the rated voltage of the electrolyzer. The first reference current is the current calculated based on the PI loop control principle.

[0193] For example, Figure 14 Here is a circuit diagram of a photohydrogen storage system in one embodiment, such as... Figure 14 As shown, the DC-DC converter includes a switching transistor S. By controlling the duty cycle of the switching transistor S, the output current I can be controlled. out The output of the DC-DC converter is connected to the electrolytic cell, and the input is connected to the photovoltaic module and the energy storage battery.

[0194] For example, Figure 15 Here is a control loop diagram of a photohydrogen storage system in one embodiment, such as... Figure 15 As shown, the outer voltage loop is set with a reference voltage V. ref It can be fixed at the rated voltage of the electrolytic cell, and the outer voltage loop outputs the first reference current I. ref1 [i], the output voltage V of the sampled DC-DC converter out [i] is used in conjunction with the reference voltage V ref Compare and perform PI control.

[0195] Step 1304: Determine the second reference current for the current daytime power generation cycle based on the operable power and output voltage of the current daytime power generation cycle.

[0196] The second reference current is a reference value used to compare with the first reference current to determine the target current. For example, the operating power P... EL [i] and the output voltage V during the current daytime power generation cycle out [i] can be divided to obtain the second reference current.

[0197] Step 1306: Determine the target current based on the first reference current and the second reference current.

[0198] The target current can be used as the current control target for PI control. For example, the target current is determined with reference to the following formula (11).

[0199]

[0200] Among them, I ref1 [i] represents the first reference current of the current daytime power generation cycle, I ref2 [i] represents the target current.

[0201] Step 1308: Based on the target current, the output current sampled at the output terminal during the current daytime power generation cycle, and the PI loop control principle, determine the duty cycle of the switching transistor of the DC-DC converter.

[0202] In current loop control, the target current is compared with the output current I of the current daytime power generation cycle. out [i] In comparison, by performing PI control, the duty cycle D of the switching transistor S in the DC-DC converter can be calculated.

[0203] In an exemplary embodiment, the target current is gradually varied based on a preset slope value to obtain a third reference current; based on the third reference current, the output current sampled at the output terminal during the current daytime power generation cycle, and the PI loop control principle, the duty cycle of the switching transistor of the DC-DC converter is determined.

[0204] The preset slope gradient value is a reference value used to gradually change the current, and can be set to 1-3% of the electrolyzer's rated current. The third reference current is the current value obtained by gradually changing the target current. Considering that the electrolyzer is extremely sensitive to sudden changes in input current, these changes can cause local temperature gradients in the membrane electrode assembly (MEA). Due to the difference in thermal expansion coefficients between the membrane material and the catalyst material, uneven material expansion can lead to stress fracture. The generation and detachment of bubbles on the electrode surface require time. If a sudden increase in current causes a sudden increase in the gas production rate, the bubbles can clog the electrode pores, forming local hot spots that can lead to membrane burn-through. Furthermore, sudden current changes can also cause degradation of potential-sensitive catalysts. Therefore, the rate of change of the electrolyzer's input current is controlled within a safe range, and the target current I... ref2 [i] The reference current I is obtained by applying a gradual change with a fixed slope. ref3 [i] The duty cycle D of the inner current loop output acts on the switching transistor S, thereby realizing the current and power control of the electrolytic cell.

[0205] Figure 16 This is a schematic diagram of the current change in a current-gradient processing embodiment, such as... Figure 16 As shown, a gradual current variation is used; if I out [i]<I ref2 [i],I ref3 [i] can slowly rise to the level of Iref2 [i] Equal current values, if I out [i]>I ref2 [i],I ref3 [i] can be slowly reduced to the level of I. ref2 [i] Equal current values. It should be noted that... Figure 16 This shows how different current values ​​change over time, where I... ref2 I ref3 and I out This is a simplified form that omits the time variable.

[0206] In this embodiment, the current is limited and gradually varied to avoid sudden changes in the input current of the electrolyzer, thereby reducing the risk of membrane material stress rupture, membrane burn-through, and catalyst degradation, and extending the service life of the electrolyzer.

[0207] It should be understood that although the steps in the flowcharts of the above embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages in other steps. It is understood that the steps in different embodiments can be freely combined as needed, and all non-contradictory solutions formed by such combinations are within the scope of protection of this application.

[0208] Based on the same inventive concept, this application also provides a power control device for a photohydrogen storage system to implement the aforementioned power control method. The solution provided by this device is similar to the solution described in the above method. Therefore, the specific limitations in one or more embodiments of the photohydrogen storage system power control device provided below can be found in the limitations of the photohydrogen storage system power control method described above, and will not be repeated here.

[0209] In one exemplary embodiment, such as Figure 17 As shown, a power control device 1700 for a photovoltaic hydrogen storage system is provided, including: a photovoltaic power prediction module 1701, a battery average power determination module 1702, a total average power determination module 1703, an operational power determination module 1704, and an electrolyzer power control module 1705. The photovoltaic hydrogen storage system includes a DC-DC converter, and photovoltaic modules, an electrolyzer, and a storage battery, which are electrically connected to the DC-DC converter respectively.

[0210] The photovoltaic power prediction module 1701 is used to predict the future photovoltaic power generation of photovoltaic modules in a future time period, which is the period from the current daytime power generation cycle to the end of the daytime power generation cycle.

[0211] The battery average power determination module 1702 is used to determine the average battery power that the electrolyzer can obtain in the future time period based on the output battery power of the energy storage battery in the current daytime power generation cycle.

[0212] The total average power determination module 1703 is used to determine the total average power that the electrolyzer can obtain in the future time period based on the future photovoltaic power generation and the output battery power.

[0213] The operable power determination module 1704 is used to determine the operable power of the electrolyzer for the current daytime power generation cycle based on the average power of the available battery, the average total power available, and the actual photovoltaic power output to the DC converter by the photovoltaic module during the current daytime power generation cycle.

[0214] The electrolytic cell power control module 1705 is used to control the DC-DC converter to output operating power to the electrolytic cell based on the loop control principle.

[0215] Each module in the power control device of the aforementioned photovoltaic hydrogen storage system can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0216] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps in the above method embodiments.

[0217] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above method embodiments.

[0218] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0219] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0220] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for power control of a light hydrogen storage system, characterized in that, The light hydrogen storage system comprises a direct current converter, and a photovoltaic assembly, an electrolytic tank and an energy storage battery electrically connected with the direct current converter respectively, and the method comprises: forecasting a future photovoltaic available power of the photovoltaic assembly in a future time period, the future time period being a time period from a current daytime power generation cycle to a daytime power generation termination cycle; determining an obtainable average battery power of the electrolytic tank in the future time period according to an outputtable battery power of the energy storage battery in the current daytime power generation cycle; determining an obtainable total average power of the electrolytic tank in the future time period according to the future photovoltaic available power and the outputtable battery power; determining a runable power of the electrolytic tank in the current daytime power generation cycle based on the obtainable average battery power, the obtainable total average power and an actual photovoltaic power outputted by the photovoltaic assembly to the direct current converter in the current daytime power generation cycle; controlling the direct current converter to output the runable power to the electrolytic tank based on a loop control principle; wherein, the determining of the obtainable total average power of the electrolytic tank in the future time period according to the future photovoltaic available power and the outputtable battery power further comprises: calculating a power deviation degree of the actual photovoltaic power in the current daytime power generation cycle; if the power deviation degree is less than a preset negative deviation threshold, determining a power correction coefficient of the current daytime power generation cycle as a sum of a power correction coefficient of a previous daytime power generation cycle and the power deviation degree; if the power deviation degree is greater than or equal to the negative deviation threshold and less than or equal to a preset positive deviation threshold, determining the power correction coefficient of the current daytime power generation cycle as the power correction coefficient of the previous daytime power generation cycle; if the power deviation degree is greater than the preset positive deviation threshold, determining the power correction coefficient of the current daytime power generation cycle as a difference between the power correction coefficient of the previous daytime power generation cycle and the power deviation degree; updating and correcting the future photovoltaic available power of the current daytime power generation cycle according to the power correction coefficient of the current daytime power generation cycle.

2. The method of claim 1, wherein, The forecasting of the future photovoltaic available power of the photovoltaic assembly in a future time period comprises: determining a predicted photovoltaic power of the current daytime power generation cycle based on a solar radiation intensity, an ambient temperature and a wind speed of the current daytime power generation cycle; calculating a product of the predicted photovoltaic power and a time length of the current daytime power generation cycle to obtain a predicted power generation amount of the current daytime power generation cycle; accumulating the predicted power generation amounts of each power generation cycle in the future time period to obtain the future photovoltaic available power.

3. The method of claim 1, wherein, The determining of the obtainable average battery power of the electrolytic tank in the future time period according to the outputtable battery power of the energy storage battery in the current daytime power generation cycle comprises: estimating the outputtable battery power of the energy storage battery based on a battery state of charge and a battery state of health of the energy storage battery in the current daytime power generation cycle; determining the obtainable average battery power of the future time period based on the length of the current daytime generation period, the number of periods between the current daytime generation period and the daytime generation termination period, and the outputtable battery power.

4. The method of claim 1, wherein, determining the obtainable total average power of the electrolyzer in the future time period based on the future photovoltaic available power and the outputtable battery power, including: summing the future photovoltaic available power and the outputtable battery power to obtain a future total available power; determining the obtainable total average power of the future time period based on the length of the current daytime generation period, the number of periods between the current daytime generation period and the daytime generation termination period, and the future total available power.

5. The method of claim 1, wherein, determining the operable power of the electrolyzer in the current daytime generation period based on the obtainable average battery power, the obtainable total average power, and the actual photovoltaic power outputted by the photovoltaic assembly to the DC converter in the current daytime generation period, including: if the obtainable average battery power≤the obtainable total average power<the electrolyzer power low threshold<the electrolyzer rated power, determining the operable power of the electrolyzer in the current daytime generation period as 0; if the obtainable average battery power<the electrolyzer power low threshold≤the obtainable total average power<the electrolyzer rated power, determining the operable power of the electrolyzer in the current daytime generation period according to the actual photovoltaic power of the photovoltaic assembly in the current daytime generation period and the electrolyzer power low threshold; if the obtainable average battery power<the electrolyzer power low threshold<the electrolyzer rated power≤the obtainable total average power, determining the operable power of the electrolyzer in the current daytime generation period according to the actual photovoltaic power of the photovoltaic assembly in the current daytime generation period and the electrolyzer power low threshold; if the electrolyzer power low threshold≤the obtainable average battery power≤the obtainable total average power<the electrolyzer rated power, determining the operable power of the electrolyzer in the current daytime generation period according to the actual photovoltaic power of the photovoltaic assembly in the current daytime generation period and the electrolyzer power low threshold; if the electrolyzer power low threshold≤the obtainable average battery power<the electrolyzer rated power≤the obtainable total average power, determining the operable power of the electrolyzer in the current daytime generation period according to the actual photovoltaic power of the photovoltaic assembly in the current daytime generation period and the electrolyzer rated power; if the electrolyzer power low threshold<the electrolyzer rated power≤the obtainable average battery power≤the obtainable total average power, determining the operable power of the electrolyzer in the current daytime generation period as the electrolyzer rated power.

6. The method of claim 1, wherein, the calculation of the power deviation degree of the actual photovoltaic power in the current daytime generation period, including: summing the predicted photovoltaic power in the historical daytime generation period to obtain a first photovoltaic power total value; summing the actual photovoltaic power in the historical daytime generation period to obtain a second photovoltaic power total value; obtaining a power difference value according to the difference between the first photovoltaic power total value and the second photovoltaic power total value; According to a ratio of the power difference and the second total photovoltaic power value, a power deviation degree in the current daytime power generation period is obtained.

7. The method of claim 1, wherein, The output end of the direct current converter is a port connecting the direct current converter and the electrolytic tank, and the direct current converter outputs the operable power to the electrolytic tank based on the loop control principle, which includes: Based on the PI loop control principle, the set reference voltage, and the output voltage of the output end of the direct current converter sampled in the current daytime power generation period, a first reference current of the current daytime power generation period is determined. Based on the operable power of the current daytime power generation period and the output voltage in the current daytime power generation period, a second reference current of the current daytime power generation period is determined. Based on the first reference current and the second reference current, a target current is determined. Based on the target current, the output current of the output end sampled in the current daytime power generation period, and the PI loop control principle, a duty cycle of a switch tube of the direct current converter is determined.

8. The method of claim 7, wherein, The determination of the duty cycle of the switch tube of the direct current converter based on the target current, the output current of the output end sampled in the current daytime power generation period, and the PI loop control principle includes: The target current is gradually changed based on a preset slope change value to obtain a third reference current. The duty cycle of the switch tube of the direct current converter is determined based on the third reference current, the output current of the output end sampled in the current daytime power generation period, and the PI loop control principle.

9. A power control device for a light hydrogen storage system, characterized by The optical hydrogen storage system includes a direct current converter, and a photovoltaic assembly, an electrolytic tank, and an energy storage battery electrically connected to the direct current converter, respectively, and the device includes: A photovoltaic power prediction module is configured to predict a future photovoltaic power generation capacity of the photovoltaic assembly in a future time period, which is a time period from a current daytime power generation period to a daytime power generation termination period. A battery average power determination module is configured to determine an obtainable battery average power of the electrolytic tank in the future time period according to an outputtable battery power of the energy storage battery in the current daytime power generation period. A total average power determination module is configured to determine an obtainable total average power of the electrolytic tank in the future time period according to the future photovoltaic power generation capacity and the outputtable battery power. An operable power determination module is configured to determine an operable power of the electrolytic tank in the current daytime power generation period based on the obtainable battery average power, the obtainable total average power, and an actual photovoltaic power output to the direct current converter by the photovoltaic assembly in the current daytime power generation period. An electrolytic tank power control module is configured to control the direct current converter to output the operable power to the electrolytic tank based on the loop control principle. The total average power determination module is further configured to calculate a power deviation degree of the actual photovoltaic power in the current daytime power generation period. If the power deviation degree is less than a preset negative deviation threshold, a power correction coefficient of the current daytime power generation period is determined as a sum of a power correction coefficient of a previous daytime power generation period and the power deviation degree. if the power deviation degree is greater than or equal to the negative deviation threshold and less than or equal to a preset positive deviation threshold, determining a power correction coefficient of the current daytime power generation period as a power correction coefficient of a previous daytime power generation period; if the power deviation degree is greater than the preset positive deviation threshold, determining the power correction coefficient of the current daytime power generation period as a difference between the power correction coefficient of the previous daytime power generation period and the power deviation degree; updating and correcting the future photovoltaic available power of the current daytime power generation period according to the power correction coefficient of the current daytime power generation period.

10. A light hydrogen storage system characterized by, The system comprises a direct current converter, and a photovoltaic module, an electrolytic cell and an energy storage battery electrically connected with the direct current converter respectively, and the power of the system is controlled by the method of any one of claims 1 to 8.

11. A computer readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by a processor to implement the steps of the method of any one of claims 1 to 8. The computer program is executed by a processor to implement the steps of the method of any one of claims 1 to 8.

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