Control system and method for photovoltaic off-grid hydrogen production
Through the direct current transmission system and ripple prediction model, the problem of unstable AC current when there are a large number of photovoltaic power stations is solved, and stable and low-cost photovoltaic hydrogen power supply is achieved, ensuring the power supply for hydrogen production by water electrolysis.
Patent Information
- Application Number
- CN202511025995.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-24
- Publication Date
- 2025-09-16
AI Technical Summary
When there are a large number of photovoltaic power stations, the AC current transmission process is complex and unstable, making it difficult to effectively supply power to the hydrogen production plant.
A DC power transmission system is adopted, including an inverter rectifier module, a bus control module, a transformer transmission module and an energy storage module. Through DC bus segmentation control and ripple prediction model, current stability and voltage consistency are ensured, and energy storage modules are used to balance power.
It has achieved more stable DC power transmission and lower equipment costs when the photovoltaic array is not far from the hydrogen production plant. It can balance the power when the power generation of the photovoltaic array changes, ensuring that the electrolytic cell receives stable DC power.
Smart Images
Figure CN120649048A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of photovoltaic power generation control, and in particular to a control system and method for photovoltaic off-grid hydrogen production. Background Art
[0002] Hydrogen production refers to the electrolysis of water to produce hydrogen. Off-grid photovoltaic hydrogen production uses photovoltaic power to power the electrolysis process. The hydrogen produced also serves as another form of energy storage, making off-grid photovoltaic hydrogen production a crucial prerequisite for hydrogen energy applications. Because hydrogen production requires a relatively high voltage, the electricity generated by photovoltaic power generation must pass through a booster before it can be used for electrolysis. If multiple photovoltaic power stations are supplying power to a hydrogen production plant, the combined current of each group must be the same.
[0003] The above-mentioned existing technical solutions have the following defects: photovoltaic power stations usually use traditional AC power supply to supply power to hydrogen production plants. However, if the number of photovoltaic power stations is large, the AC power needs to be calibrated in phase, so the current transmission process will be more complicated and unstable. Summary of the Invention
[0004] In order to make the current transmission process simple and stable, the present application provides a control system and method for photovoltaic off-grid hydrogen production.
[0005] On the one hand, the present application provides a control system for photovoltaic off-grid hydrogen production using the following technical solutions: A control system for off-grid photovoltaic hydrogen production includes multiple photovoltaic arrays and multiple electrolyzers. A photovoltaic power supply system is connected between the photovoltaic arrays and the electrolyzers. The photovoltaic power supply system includes multiple inverter rectifier modules, a busbar control module, multiple voltage conversion and transmission modules, and multiple energy storage modules. The inverter-rectifier module is connected to the photovoltaic array and receives the DC power output by the photovoltaic array. The inverter-rectifier module converts the DC power into AC power through the inverter, then transforms the voltage to the same value through the AC transformer, and then converts the DC power into DC power through the rectifier, and outputs the DC power. The bus control module includes a DC bus with a preset minimum voltage value. The DC bus connects all the inverter and rectifier modules and all the transformer and transmission modules through branches and receives the output DC power. The bus control module divides all the branches into multiple power supply groups, each of which includes a branch connected to the inverter and rectifier module, a branch connected to the transformer and transmission module, and a branch connected to the energy storage module. Under normal circumstances, the bus control module controls adjacent power supply groups to disconnect from each other. When the DC voltage output by the inverter and rectifier module of a power supply group is lower than the minimum voltage value, the adjacent power supply group is connected to the power supply group. The transformer and power transmission module receives the DC power output by the bus control module, boosts the received DC power, and transmits it to the electrolytic cell; The energy storage module receives the DC power output by the bus control module, stores the received DC power, and discharges the DC power to the DC bus when the voltage of the DC bus connected to the energy storage module in the bus control module decreases.
[0006] By adopting this solution, after the photovoltaic array generates electricity, the current passes through an inverter, AC transformer, and rectifier to obtain relatively stable DC power with a uniform voltage. This DC power is then transmitted directly to the electrolytic cell via a DC bus, where it is boosted and used to produce hydrogen through water electrolysis. Because DC power transmission requires lower transmission requirements but has higher losses, it can be more stable than AC power transmission when the photovoltaic array is close to the hydrogen production plant, resulting in lower equipment costs. The DC bus is divided into multiple sections, and this system can also balance power between different power supply groups by controlling the on / off of each DC bus section when the power generation of a certain part of the photovoltaic array decreases or stops, ensuring that the electrolytic cell receives DC power with a stable voltage.
[0007] Preferably, the energy storage module includes a DC transformer connected to the DC bus and an energy storage battery connected to the DC transformer; A circuit breaker is provided between two adjacent power supply groups of the busbar control module.
[0008] By adopting the above solution, the energy storage battery receives the boosted DC power for storage, reducing power loss during storage. The circuit breaker can simply and quickly control the circuit on and off.
[0009] Preferably, the photovoltaic power supply system also includes a power supply management module, which is preset with a standard voltage value. The power supply management module monitors the DC voltage value output by each inverter rectifier module, and calculates the DC voltage value that the DC bus is expected to transmit to each transformer transmission module based on the DC voltage value corresponding to each power supply group. When the DC voltage value that a certain transformer transmission module is expected to receive is lower than the standard voltage value, and the energy storage capacity of the energy storage module of the adjacent power supply group is higher than the energy storage capacity of the energy storage module of the power supply group, the adjacent power supply groups are controlled to be connected.
[0010] By adopting this solution, when the voltage of a certain DC bus segment decreases, the system will attempt to determine whether there is excess power in the energy storage batteries connected to the adjacent DC bus segment. If a battery with higher power is found, the system will synchronize the voltages of the two DC bus segments by connecting the two DC bus segments, allowing the energy storage battery with higher power to also participate in the discharge, thereby balancing the power of all energy storage batteries in the entire system.
[0011] Preferably, the photovoltaic power supply system further includes a current monitoring module, a model training module and an intelligent control module; The current monitoring module monitors the ripple coefficient of the direct current output by each photovoltaic array and the inverter rectifier module, monitors the ripple coefficient of the direct current received by the transformer transmission module, and transmits the monitored data to the model training module and the intelligent control module; The model training module is preset with a convolutional neural model, sets experimental parameters and adjusts the photovoltaic array and the inverter rectifier module according to the experimental parameters, trains the convolutional neural model according to the acquired DC ripple coefficient, and obtains a ripple prediction model. The ripple prediction model receives the ripple coefficient of the DC power output by the photovoltaic array and the inverter rectifier module, and then predicts the ripple coefficient of the DC power received by the transformer transmission module within a set time, and transmits the ripple prediction model to the intelligent control module; The intelligent control module is preset with a standard value for the ripple coefficient. After receiving new data, the intelligent control module uses a ripple prediction model to calculate the ripple coefficient of the DC power output by each photovoltaic array and the inverter rectifier module to predict the ripple coefficient of the DC power received by the transformer and transmission module within a set time. If it is predicted that the ripple coefficient of the DC power received by the transformer and transmission module within the set time exceeds the standard value for the ripple coefficient, an early warning message is issued and the parameters of the inverter and rectifier module are adjusted.
[0012] The above solution, which employs water electrolysis to produce hydrogen, imposes stringent requirements on the power supply's ripple coefficient. The output ripple system typically cannot be less than 1%, otherwise it will interfere with the electrochemical reaction. The system uses a ripple prediction model to predict the ripple coefficient for a certain period of time in the future. If the ripple system is likely to exceed the standard value, the system will alert the user and attempt to adjust the inverter and rectifier to ensure that the ripple coefficient of the electrolytic cell remains below a safe value. The ripple prediction model can also be used to simulate the power supply system and quickly adjust it to a photovoltaic off-grid hydrogen production system suitable for the region.
[0013] Preferably, the intelligent control module compares the predicted ripple coefficient of the direct current power received by the current transformer and transmission module with the ripple coefficient of the direct current power actually received by the transformer and transmission module. If they are different, the ripple coefficient of the direct current power output by the current photovoltaic array and inverter rectifier module and the ripple coefficient of the direct current power actually received by the transformer and transmission module are transmitted to the model training module, and the model training module corrects the ripple prediction model according to the received values.
[0014] By adopting the above solution, the system can continuously revise the ripple prediction model according to actual monitoring results during use, so as to ensure that the prediction results of the ripple prediction model can become more and more accurate.
[0015] On the other hand, the present application provides a control method for photovoltaic off-grid hydrogen production using the following technical solutions: A control method for off-grid photovoltaic hydrogen production, comprising a plurality of photovoltaic arrays and a plurality of electrolyzers, further comprising the following steps: The DC power output by the photovoltaic array is converted into AC power through an inverter, then transformed to the same voltage value through an AC transformer, and then converted into DC power output through a rectifier; Set the DC bus connected to all rectifiers and preset the minimum voltage value; The DC bus is divided into multiple sections, and all branches of each section of the DC bus together form a power supply group; Each power supply group is also connected to multiple DC transformers, which are connected to the electrolyzer and energy storage battery; Under normal conditions, adjacent power supply groups are controlled to disconnect from each other; When the DC voltage output by the rectifier of a certain power supply group is lower than the minimum voltage value, the adjacent power supply group is connected to the power supply group; When the voltage in the DC bus connected to the energy storage battery drops, discharge is performed to the DC bus.
[0016] By adopting this solution, after the photovoltaic array generates electricity, the current passes through an inverter, AC transformer, and rectifier to obtain relatively stable DC power with a uniform voltage. This DC power is then transmitted directly to the electrolytic cell via a DC bus, where it is boosted and used to produce hydrogen through water electrolysis. Because DC power transmission requires lower transmission requirements but has higher losses, it can be more stable than AC power transmission when the photovoltaic array is close to the hydrogen production plant, resulting in lower equipment costs. The DC bus is divided into multiple sections, and this system can also balance power between different power supply groups by controlling the on / off of each DC bus section when the power generation of a certain part of the photovoltaic array decreases or stops, ensuring that the electrolytic cell receives DC power with a stable voltage.
[0017] Preferably, the method further comprises the following steps: Preset standard voltage value; Monitor the DC voltage value output by each rectifier, and calculate the DC voltage value that the DC bus is expected to transmit to each DC transformer based on the DC voltage value corresponding to each power supply group; When the DC voltage value expected to be received by a DC transformer is lower than the standard voltage value, and the energy storage capacity of the energy storage battery of the adjacent power supply group is higher than the energy storage capacity of the energy storage battery of the power supply group, the adjacent power supply group is controlled to be connected.
[0018] By adopting this solution, when the voltage of a certain DC bus segment decreases, the system will attempt to determine whether there is excess power in the energy storage batteries connected to the adjacent DC bus segment. If a battery with higher power is found, the system will synchronize the voltages of the two DC bus segments by connecting the two DC bus segments, allowing the energy storage battery with higher power to also participate in the discharge, thereby balancing the power of all energy storage batteries in the entire system.
[0019] Preferably, the method further comprises the following steps: Preset convolutional neural model and ripple coefficient standard value Monitor the ripple factor of the DC power output by each photovoltaic array and rectifier; monitoring a ripple factor of the DC power received by each DC transformer connected to the electrolytic cell; Set experimental parameters and adjust the photovoltaic array, inverter, and rectifier according to the experimental parameters to obtain the ripple coefficient of the DC power used in the experiment; The convolutional neural network model is trained based on the ripple coefficient of the DC power used in the experiment to obtain a ripple prediction model. The ripple prediction model receives the ripple coefficient of the DC power output by the photovoltaic array and the rectifier and then predicts the ripple coefficient of the DC power received by the DC transformer within a set time. When a new DC power ripple coefficient is received, the ripple coefficient of the DC power output by each photovoltaic array and rectifier is used to predict the ripple coefficient of the DC power received by the DC transformer within a set time through a ripple prediction model; If it is predicted that the ripple factor of the DC power received by the DC transformer within the set time exceeds the ripple factor standard value, an early warning message will be issued and the parameters of the inverter and rectifier will be adjusted.
[0020] The above solution, which employs water electrolysis to produce hydrogen, imposes stringent requirements on the power supply's ripple coefficient. The output ripple system typically cannot be less than 1%, otherwise it will interfere with the electrochemical reaction. The system uses a ripple prediction model to predict the ripple coefficient for a certain period of time in the future. If the ripple system is likely to exceed the standard value, the system will alert the user and attempt to adjust the inverter and rectifier to ensure that the ripple coefficient of the electrolytic cell remains below a safe value. The ripple prediction model can also be used to simulate the power supply system and quickly adjust it to a photovoltaic off-grid hydrogen production system suitable for the region.
[0021] Preferably, the method further comprises the following steps: comparing the predicted ripple coefficient of the direct current power currently received by the direct current transformer with the ripple coefficient of the direct current power actually received by the direct current transformer; If they are not the same, the ripple prediction model is corrected using the ripple coefficient of the DC power output by the current photovoltaic array and rectifier and the ripple coefficient of the DC power actually received by the DC transformer.
[0022] By adopting the above solution, the system can continuously revise the ripple prediction model according to actual monitoring results during use, so as to ensure that the prediction results of the ripple prediction model can become more and more accurate.
[0023] In summary, the present invention has the following beneficial effects: 1. After generating electricity, the photovoltaic array passes the current through an inverter, transformer, and rectifier to generate relatively stable DC power with a consistent voltage. This DC power is then transmitted directly to the electrolytic cell via a DC bus, where it is boosted and used to produce hydrogen through water electrolysis. Because DC power transmission requires less power but has higher losses, it can be more stable than AC power transmission when the photovoltaic array is close to the hydrogen production plant, resulting in lower equipment costs. The DC bus is divided into multiple sections. This system can also control the on / off state of each DC bus section to balance power between different power supply groups when the power generation of a certain section of the photovoltaic array decreases or stops, ensuring that the electrolytic cell receives DC power with a stable voltage. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 This is the overall system block diagram of Example 1 of the present application.
[0025] Figure 2 This is a circuit diagram of Example 1 of the present application.
[0026] Figure 3 This is a system block diagram of the second embodiment of the present application.
[0027] Description of reference numerals: 1. Photovoltaic array; 2. Electrolyzer; 3. Photovoltaic power supply system; 31. Inverter-rectifier module; 311. Inverter; 312. AC transformer; 313. Rectifier; 32. Bus control module; 321. DC bus; 322. Circuit breaker; 33. Transformer transmission module; 331. DC transformer; 34. Energy storage module; 341. Energy storage battery; 35. Power supply management module; 36. Current monitoring module; 37. Model training module; 38. Intelligent control module. DETAILED DESCRIPTION
[0028] Example 1: This application discloses a control system for photovoltaic off-grid hydrogen production, such as Figure 1 As shown, the system includes multiple photovoltaic arrays 1 and multiple electrolyzers 2. A photovoltaic power supply system 3 is connected between the photovoltaic arrays 1 and the electrolyzers 2. The photovoltaic power supply system 3 includes multiple inverter rectifier modules 31, a busbar control module 32, multiple voltage conversion and transmission modules 33, and multiple energy storage modules 34. The photovoltaic arrays 1 generate direct current (DC), which is received by the electrolyzers 2 to electrolyze water to produce hydrogen.
[0029] like Figure 1 and Figure 2 As shown, the inverter rectifier module 31 is connected to the photovoltaic array 1 and receives the DC power output by the photovoltaic array 1. The inverter rectifier module 31 converts the DC power into AC power through the inverter 311, and then transforms it to the same voltage value through the AC transformer 312, and then converts it into DC power through the rectifier 313, and outputs the DC power.
[0030] like Figure 1and Figure 2 As shown, the bus control module 32 includes a DC bus 321 with a preset minimum voltage value. The DC bus 321 connects all the inverter and rectifier modules 31 and all the transformer and transmission modules 33 through branches and receives the output DC power. The bus control module 32 divides all the branches into multiple power supply groups. Each power supply group includes a branch connected to the inverter and rectifier module 31, a branch connected to the transformer and transmission module 33, and a branch connected to the energy storage module 34. A circuit breaker 322 is provided between two adjacent power supply groups of the bus control module 32. The bus control module 32 controls the adjacent power supply groups to disconnect from each other under normal conditions through the circuit breaker 322. When the DC voltage output by the inverter and rectifier module 31 of a power supply group is lower than the minimum voltage value, the adjacent power supply group is connected to the power supply group.
[0031] like Figure 1 and Figure 2 As shown, the transformer and transmission module 33 receives the DC power output by the bus control module 32, boosts the received DC power, and transmits it to the electrolyzer 2. The energy storage module 34 includes a DC transformer 331 connected to the DC bus 321 and an energy storage battery connected to the DC transformer 331. The energy storage module 34 receives the DC power output by the bus control module 32, and the energy storage battery stores the received DC power. When the voltage of the DC bus 321 connected to the energy storage module 34 in the bus control module 32 decreases, the energy storage battery discharges the power to the DC bus 321 through the DC transformer 331.
[0032] The implementation principle of a control system and method for photovoltaic off-grid hydrogen production in the embodiment of the present application is as follows: after the photovoltaic array 1 generates electricity, the current passes through the inverter 311, the AC transformer 312, and the rectifier 313 to obtain relatively stable direct current with the same voltage. The direct current is directly transmitted to the electrolytic cell through the DC bus 321, and after being boosted, it participates in the electrolysis of water to produce hydrogen. Because the combined transmission requirements of direct current are low but the loss is large, it can be more stable than AC transmission when the photovoltaic array 1 is not far from the hydrogen production plant, and the equipment cost is lower. The DC bus 321 is divided into multiple sections. The system can also balance the power of different power supply groups when the power generation of a certain part of the photovoltaic array 1 is reduced or stopped by controlling the on and off of each section of the DC bus 321, so as to ensure that the electrolytic cell can receive DC power with stable voltage as much as possible.
[0033] Example 2: This embodiment of the present application discloses a control system for photovoltaic off-grid hydrogen production, which is different from Example 1 in that: Figure 3 As shown, the photovoltaic power supply system 3 also includes a power supply management module 35 , a current monitoring module 36 , a model training module 37 and an intelligent control module 38 .
[0034] like Figure 3As shown, the power supply management module 35 is preset with a standard voltage value. The power supply management module 35 monitors the DC voltage output by each inverter-rectifier module 31 and calculates the DC voltage value that the DC bus 321 is expected to transmit to each transformer and transmission module 33 based on the DC voltage value corresponding to each power supply group. When the DC voltage value expected to be received by a transformer and transmission module 33 is lower than the standard voltage value, and the energy storage module 34 of the adjacent power supply group has a higher energy storage module 34 capacity than that of the power supply group, the adjacent power supply group is controlled to connect. When the voltage of a certain DC bus 321 section decreases, the system attempts to determine whether there is excess power in the energy storage battery 341 connected to the adjacent DC bus 321. If an energy storage battery 341 with higher power is found, the system connects the two DC bus sections 321 to synchronize the voltages of the two DC bus sections 321, allowing the energy storage battery 341 with higher power to also participate in the discharge, thereby balancing the power of all energy storage batteries 341 in the entire system.
[0035] like Figure 3 As shown, the current monitoring module 36 monitors the ripple coefficient of the DC power output by each photovoltaic array 1 and the inverter rectifier module 31, monitors the ripple coefficient of the DC power received by the transformer transmission module 33, and transmits the monitored data to the model training module 37 and the intelligent control module 38.
[0036] like Figure 3 As shown, the model training module 37 is preset with a convolutional neural model, experimental parameters are set and the photovoltaic array 1 and the inverter rectifier module 31 are adjusted according to the experimental parameters, and the convolutional neural model is trained according to the obtained ripple coefficient of the DC power to obtain a ripple prediction model. The ripple prediction model receives the ripple coefficient of the DC power output by the photovoltaic array 1 and the inverter rectifier module 31, and then predicts the ripple coefficient of the DC power received by the transformer transmission module 33 within the set time, and transmits the ripple prediction model to the intelligent control module 38.
[0037] like Figure 3As shown, the intelligent control module 38 is preset with a standard ripple coefficient value. After receiving new data, the intelligent control module 38 uses the ripple coefficient of the DC power output by each photovoltaic array 1 and the inverter and rectifier module 31 to predict the ripple coefficient of the DC power received by the transformer and transmission module 33 within a set time period using a ripple prediction model. If the ripple coefficient of the DC power received by the transformer and transmission module 33 within the set time period is predicted to exceed the standard ripple coefficient value, an early warning message is issued and the parameters of the inverter and rectifier module 31 are adjusted. The intelligent control module 38 compares the predicted ripple coefficient of the DC power currently received by the transformer and transmission module 33 with the ripple coefficient of the DC power actually received by the transformer and transmission module 33. If they are different, the intelligent control module 38 transmits the current ripple coefficient of the DC power output by the photovoltaic array 1 and the inverter and rectifier module 31 and the ripple coefficient of the DC power actually received by the transformer and transmission module 33 to the model training module 37. The model training module 37 then modifies the ripple prediction model based on the received values. During use, the system can continuously revise the ripple prediction model according to actual monitoring results to ensure that the prediction results of the ripple prediction model can become more and more accurate.
[0038] Hydrogen production from water electrolysis has strict requirements for the power supply's ripple coefficient. The output ripple system typically cannot be less than 1%, otherwise it will interfere with the electrochemical reaction. The system uses a ripple prediction model to predict the ripple coefficient for a certain period of time in the future. If the ripple system is likely to exceed the standard value, the system will alert the user and attempt to adjust the inverter 311 and rectifier 313 to ensure that the ripple coefficient of the electrolytic cell remains below a safe value. The ripple prediction model can also be used to simulate the power supply system and quickly adjust it to suit the region's off-grid photovoltaic hydrogen production system.
[0039] Example 3: This embodiment of the present application discloses a control method for off-grid photovoltaic hydrogen production, including multiple photovoltaic arrays 1 and multiple electrolyzers 2. The specific steps are as follows: The DC power output from PV array 1 is converted to AC power via inverter 311, then transformed to a uniform voltage via AC transformer 312, and finally converted to DC power via rectifier 313. Inverter 311, AC transformer 312, and rectifier 313 are all located near PV array 1 to stabilize the power as soon as PV array 1 generates power.
[0040] A DC bus 321 connected to all rectifiers 313 is provided, and a minimum voltage value is preset.
[0041] The DC bus 321 is divided into multiple sections, and all branches of each section of the DC bus 321 together form a power supply group.
[0042] Each power supply group is further connected to a plurality of DC transformers 331 , and the DC transformers 331 are connected to the electrolytic cell 2 and the energy storage battery 341 .
[0043] Under normal circumstances, adjacent power supply groups are controlled to disconnect from each other.
[0044] When the DC voltage output by the rectifier 313 of a certain power supply group is lower than the minimum voltage value, the adjacent power supply group is connected to the power supply group.
[0045] When the voltage of the DC bus 321 connected to the energy storage battery 341 decreases, the DC bus 321 is discharged.
[0046] Example 4: This embodiment of the present application discloses a control method for photovoltaic off-grid hydrogen production, which differs from Example 3 in that it further includes the following steps: Preset standard voltage values, convolutional neural model and ripple coefficient standard values.
[0047] The DC voltage value output by each rectifier 313 is monitored, and the DC voltage value that the DC bus 321 is expected to transmit to each DC transformer 331 is calculated based on the DC voltage value corresponding to each power supply group.
[0048] The ripple factor of the direct current output by each photovoltaic array 1 and the rectifier 313 is monitored.
[0049] The ripple factor of the DC power received by each DC transformer 331 connected to the electrolytic cell is monitored.
[0050] Experimental parameters are set and the photovoltaic array 1, the inverter 311 and the rectifier 313 are adjusted according to the experimental parameters to obtain the ripple coefficient of the direct current used in the experiment.
[0051] The convolutional neural model is trained based on the ripple coefficient of the DC power used in the experiment to obtain a ripple prediction model. The ripple prediction model receives the ripple coefficient of the DC power output by the photovoltaic array 1 and the rectifier 313 and then predicts the ripple coefficient of the DC power received by the DC transformer 331 within a set time.
[0052] When the DC voltage value expected to be received by a certain DC transformer 331 is lower than the standard voltage value, and the storage capacity of the energy storage battery 341 of the adjacent power supply group is higher than the storage capacity of the energy storage battery 341 of the power supply group, the adjacent power supply groups are controlled to be connected.
[0053] When a new ripple coefficient of DC power is received, the ripple coefficient of the DC power output by each photovoltaic array 1 and the rectifier 313 is used by the ripple prediction model to predict the ripple coefficient of the DC power received by the DC transformer 331 within a set time.
[0054] If it is predicted that the ripple coefficient of the DC power received by the DC transformer 331 exceeds the ripple coefficient standard value within the set time, a warning message is issued and the parameters of the inverter 311 and the rectifier 313 are adjusted.
[0055] The predicted ripple coefficient of the DC power currently received by the DC transformer 331 is compared with the ripple coefficient of the DC power actually received by the DC transformer 331 .
[0056] If they are not the same, the ripple prediction model is corrected using the ripple coefficient of the DC power currently output by the photovoltaic array 1 and the rectifier 313 and the ripple coefficient of the DC power actually received by the DC transformer 331 .
[0057] The embodiments of this specific implementation method are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the scope of protection of the present invention.
Claims
1. A control system for off-grid photovoltaic hydrogen production, characterized in that: The invention comprises a plurality of photovoltaic arrays (1) and a plurality of electrolytic cells (2), wherein a photovoltaic power supply system (3) is connected between the photovoltaic arrays (1) and the electrolytic cells (2), and the photovoltaic power supply system (3) comprises a plurality of inverter rectifier modules (31), a busbar control module (32), a plurality of voltage conversion transmission modules (33), and a plurality of energy storage modules (34): The inverter rectifier module (31) is connected to the photovoltaic array (1) and receives direct current output by the photovoltaic array (1). The inverter rectifier module (31) converts the direct current into alternating current through an inverter (311), then converts the voltage to the same value through an alternating current transformer (312), and then converts the voltage into direct current through a rectifier (313), and outputs the direct current. The bus control module (32) includes a DC bus (321) with a preset minimum voltage value. The DC bus (321) is connected to all the inverter rectifier modules (31) and all the transformer transmission modules (33) through branches and receives the output DC power. The bus control module (32) divides all the branches into multiple power supply groups, each power supply group includes a branch connected to the inverter rectifier module (31), a branch connected to the transformer transmission module (33), and a branch connected to the energy storage module (34). The bus control module (32) controls adjacent power supply groups to disconnect from each other under normal conditions. When the DC voltage output by the inverter rectifier module (31) of a certain power supply group is lower than the minimum voltage value, the adjacent power supply group is connected to the power supply group. The voltage conversion and transmission module (33) receives the direct current output by the bus control module (32), boosts the received direct current, and transmits it to the electrolytic cell (2); The energy storage module (34) receives direct current output by the bus control module (32), stores the received direct current, and discharges the direct current to the direct current bus (321) when the voltage in the direct current bus (321) connected to the energy storage module (34) in the bus control module (32) decreases.
2. A control system for off-grid photovoltaic hydrogen production according to claim 1, characterized in that: The energy storage module (34) includes a DC transformer (331) connected to the DC bus (321) and an energy storage battery connected to the DC transformer (331); A circuit breaker (322) is provided between two adjacent power supply groups of the busbar control module (32).
3. A control system for off-grid photovoltaic hydrogen production according to claim 1, characterized in that: The photovoltaic power supply system (3) further comprises a power supply management module (35), wherein the power supply management module (35) is preset with a standard voltage value. The power supply management module (35) monitors the DC voltage value output by each inverter rectifier module (31), and calculates the DC voltage value that the DC bus (321) is expected to transmit to each transformer transmission module (33) based on the DC voltage value corresponding to each power supply group. When the DC voltage value that a transformer transmission module (33) is expected to receive is lower than the standard voltage value, and the energy storage module (34) of an adjacent power supply group has a higher energy storage capacity than the energy storage module (34) of the power supply group, the adjacent power supply groups are controlled to be connected.
4. A control system for off-grid photovoltaic hydrogen production according to claim 1, characterized in that: The photovoltaic power supply system (3) further includes a current monitoring module (36), a model training module (37) and an intelligent control module (38); The current monitoring module (36) monitors the ripple coefficient of the direct current output by each photovoltaic array (1) and the inverter rectifier module (31), monitors the ripple coefficient of the direct current received by the transformer transmission module (33), and transmits the monitored data to the model training module (37) and the intelligent control module (38); The model training module (37) is preset with a convolutional neural model, sets experimental parameters and adjusts the photovoltaic array (1) and the inverter rectifier module (31) according to the experimental parameters, trains the convolutional neural model according to the acquired ripple coefficient of the direct current, and obtains a ripple prediction model. The ripple prediction model receives the ripple coefficient of the direct current output by the photovoltaic array (1) and the inverter rectifier module (31), and then predicts the ripple coefficient of the direct current received by the transformer transmission module (33) within a set time, and transmits the ripple prediction model to the intelligent control module (38); The intelligent control module (38) is preset with a ripple coefficient standard value. After receiving new data, the intelligent control module (38) uses a ripple prediction model to predict the ripple coefficient of the direct current output by each photovoltaic array (1) and the inverter rectifier module (31) to predict the ripple coefficient of the direct current received by the transformer transmission module (33) within a set time. If it is predicted that the ripple coefficient of the direct current received by the transformer transmission module (33) within the set time exceeds the ripple coefficient standard value, a warning message is issued and the parameters of the inverter rectifier module (31) are adjusted.
5. A control system for off-grid photovoltaic hydrogen production according to claim 4, characterized in that: The intelligent control module (38) compares the predicted ripple coefficient of the direct current power received by the current transformer and transmission module (33) with the ripple coefficient of the direct current power actually received by the transformer and transmission module (33). If they are different, the intelligent control module (38) transmits the ripple coefficient of the direct current power output by the current photovoltaic array (1) and the inverter and rectifier module (31) and the ripple coefficient of the direct current power actually received by the transformer and transmission module (33) to the model training module (37). The model training module (37) corrects the ripple prediction model according to the received values.
6. A control method for off-grid photovoltaic hydrogen production, characterized in that: The method comprises a plurality of photovoltaic arrays (1) and a plurality of electrolytic cells (2), and further comprises the following steps: The DC power outputted by the photovoltaic array (1) is converted into AC power through an inverter (311), then the voltage is transformed to a uniform voltage value through an AC transformer (312), and then the voltage is converted into DC power output through a rectifier (313); A DC bus (321) connected to all rectifiers (313) is provided, and a minimum voltage value is preset; The DC bus (321) is divided into multiple sections, and all branches of each section of the DC bus (321) together form a power supply group; Each power supply group is also connected to a plurality of DC transformers (331), and the DC transformers (331) are connected to the electrolytic cell (2) and the energy storage battery (341); Under normal conditions, adjacent power supply groups are controlled to disconnect from each other; When the DC voltage output by the rectifier (313) of a certain power supply group is lower than the minimum voltage value, connecting the adjacent power supply group to the power supply group; When the voltage in the DC bus (321) connected to the energy storage battery (341) decreases, discharge is performed to the DC bus (321).
7. A control method for photovoltaic off-grid hydrogen production according to claim 6, characterized in that: The following steps are also included: Preset standard voltage value; monitoring the DC voltage value output by each rectifier (313), and calculating the DC voltage value that the DC bus (321) is expected to transmit to each DC transformer (331) based on the DC voltage value corresponding to each power supply group; When the DC voltage value expected to be received by a certain DC transformer (331) is lower than the standard voltage value, and the storage capacity of the energy storage battery (341) of the adjacent power supply group is higher than the storage capacity of the energy storage battery (341) of the power supply group, the adjacent power supply groups are controlled to be connected.
8. The control method for photovoltaic off-grid hydrogen production according to claim 6, characterized in that: The following steps are also included: Preset convolutional neural model and ripple coefficient standard value monitoring the ripple factor of the direct current output by each photovoltaic array (1) and rectifier (313); monitoring the ripple factor of the direct current received by each direct current transformer (331) connected to the electrolytic cell; Setting experimental parameters and adjusting the photovoltaic array (1), the inverter (311) and the rectifier (313) according to the experimental parameters to obtain a ripple coefficient of the direct current used in the experiment; The convolutional neural model is trained based on the ripple coefficient of the direct current used in the experiment to obtain a ripple prediction model. The ripple prediction model receives the ripple coefficient of the direct current output by the photovoltaic array (1) and the rectifier (313) and predicts the ripple coefficient of the direct current received by the direct current transformer (331) within a set time. When a new ripple coefficient of direct current is received, the ripple coefficient of the direct current output by each photovoltaic array (1) and the rectifier (313) is used to predict the ripple coefficient of the direct current received by the direct current transformer (331) within a set time using a ripple prediction model; If it is predicted that the ripple coefficient of the direct current received by the direct current transformer (331) exceeds the ripple coefficient standard value within the set time, a warning message is issued and the parameters of the inverter (311) and the rectifier (313) are adjusted.
9. A control method for photovoltaic off-grid hydrogen production according to claim 8, characterized in that: The following steps are also included: Comparing the predicted ripple coefficient of the direct current power currently received by the direct current transformer (331) with the ripple coefficient of the direct current power actually received by the direct current transformer (331); If they are not the same, the ripple prediction model is corrected using the ripple coefficient of the direct current output by the current photovoltaic array (1) and the rectifier (313) and the ripple coefficient of the direct current actually received by the direct current transformer (331).