Electrolytic cell power supply control method, computer device and storage medium

Abstract

The application relates to an electrolytic tank power supply control method, computer equipment and a storage medium. A hydrogen production system to which the method is applied comprises a three-phase cascaded H-bridge connected in a delta connection method, each bridge arm of the three-phase cascaded H-bridge being connected in series by a plurality of sub-modules; a first sub-module is connected to an electrolytic tank unit through a DC-DC converter, and a second sub-module is connected to a functional unit through a DC-DC converter. The method comprises the following steps: determining power reference values of the electrolytic tank units and the functional units according to constant power consumption of each electrolytic tank unit and state information of the functional units in the second sub-module; determining a minimum reference bridge arm current based on the power reference values of the electrolytic tank units and the functional units; determining a reference value of a third harmonic circulating current actively injected based on the minimum reference bridge arm current, grid power and a peak value of a grid voltage, and further determining a bridge arm current of the three-phase cascaded H-bridge. The method can stably supply power to the electrolytic tank.

Description

Technical Field

[0001] This application relates to the field of new energy technology, and in particular to a power supply control method for an electrolytic cell, a computer device, and a storage medium. Background Technology

[0002] With the expansion of hydrogen energy applications in the clean energy sector, the demand for power supply stability in water electrolysis hydrogen production technology is becoming increasingly urgent.

[0003] As the core equipment of a hydrogen production system, the stable power supply to the electrolyzer directly determines the hydrogen production efficiency and equipment lifespan. Current power supply control methods for electrolyzers rely solely on simple direct photovoltaic power allocation and energy storage for supplementary power, failing to consider the electrolyzer's constant power consumption, resulting in insufficient power supply stability. Summary of the Invention

[0004] Therefore, it is necessary to provide an electrolytic cell power supply control method, computer equipment, and storage medium that can improve the power supply stability of electrolytic cells in response to the above-mentioned technical problems.

[0005] In a first aspect, this application provides a method for controlling the power supply of an electrolytic cell, including:

[0006] This system is applied to hydrogen production systems, which include a three-phase cascaded H-bridge connected in a delta configuration. Each arm of the cascaded H-bridge consists of multiple sub-modules connected in series. Among these sub-modules, the first sub-module is connected to an electrolyzer unit via a DC-DC converter, and the second sub-module is connected to a functional unit via a DC-DC converter. The functional unit includes a photovoltaic unit or an energy storage unit. The first and second sub-modules are different sub-modules among the multiple sub-modules, including:

[0007] Based on the constant power consumption of each electrolytic cell unit and the status information of the functional units in the second submodule, determine the power reference value of the electrolytic cell unit and the power reference value of the functional unit.

[0008] Based on the power reference values ​​of the electrolytic cell unit and the functional unit, the minimum reference bridge arm current for maintaining power balance is determined.

[0009] Based on the minimum reference arm current, grid power, and grid voltage peak value, the reference value for the actively injected third harmonic circulating current is determined; based on the reference value for the third harmonic circulating current, the arm current of the three-phase cascaded H-bridge is determined.

[0010] In a second aspect, this application also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method as described in the first aspect or any embodiment thereof.

[0011] Thirdly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method as described in the first aspect or any embodiment thereof.

[0012] Fourthly, this application also provides a computer program product, including a computer program that, when executed by a processor, implements the method as described in the first aspect or any embodiment thereof.

[0013] In the aforementioned electrolyzer power supply control method, within the hydrogen production system, the first submodule connects to the electrolyzer unit, and the second submodule connects to the photovoltaic unit or energy storage unit. This enables independent access and control of the electrolyzer's hydrogen production load and functional units, establishing a structural foundation for their coordinated operation. The electrolyzer power supply control method combines minimum reference arm current to reduce losses and third harmonic circulating current compensation to optimize power quality, determining the arm current of the three-phase cascaded H-bridge. This constructs a closed-loop regulation mechanism, ensuring power supply continuity and stability, and solving the problem of insufficient power supply stability in the electrolyzer. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of a hydrogen production system in one embodiment;

[0016] Figure 2 This is a schematic diagram of the first submodule being connected to the electrolytic cell unit via a DC-DC converter in one embodiment;

[0017] Figure 3 This is a schematic diagram of the second submodule being connected to the photovoltaic unit via a DC-DC converter in one embodiment;

[0018] Figure 4 This is a schematic diagram of the second submodule being connected to the energy storage unit via a DC-DC converter in one embodiment;

[0019] Figure 5 This is a flowchart illustrating the power supply control method for an electrolytic cell in one embodiment;

[0020] Figure 6 This is a block diagram of hierarchical collaborative control used in a modular photovoltaic energy storage hydrogen production system in one embodiment;

[0021] Figure 7 This is a block diagram of a stable power supply control system for an electrolytic cell in one embodiment;

[0022] Figure 8 This is a schematic diagram of power distribution, zero-sequence circulating current and third harmonic circulating current under four different operating conditions in one embodiment;

[0023] Figure 9 This is a schematic diagram of the bridge arm voltage, capacitor voltage, bridge arm current, and output current in operating condition 1 of one embodiment;

[0024] Figure 10 In one embodiment, the bridge arm voltage, capacitor voltage, bridge arm current, and output current are defined in operating condition 2.

[0025] Figure 11 In one embodiment, the bridge arm voltage, capacitor voltage, bridge arm current, and output current are defined in operating condition 3.

[0026] Figure 12 In one embodiment, the bridge arm voltage, capacitor voltage, bridge arm current, and output current are defined in operating condition 4.

[0027] Figure 13 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0028] 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.

[0029] To improve the stability of the power supply to the electrolyzer and the flexibility of the system, this application provides a hydrogen production system and a power supply control method for the electrolyzer applied to the hydrogen production system.

[0030] For example, such as Figure 1 The image shows a hydrogen production system provided in an embodiment of this application. The hydrogen production system includes:

[0031] The three-phase cascaded H-bridge 11 is connected by a delta connection. Each arm of the three-phase cascaded H-bridge 11 is composed of multiple sub-modules connected in series. Among the multiple sub-modules, the first sub-module is connected to the electrolytic cell unit through a DC-DC converter, and the second sub-module is connected to the photovoltaic unit or energy storage unit through a DC-DC converter. The first sub-module and the second sub-module are different sub-modules among the multiple sub-modules.

[0032] In some embodiments, such as Figure 1 As shown, the three-phase cascaded H-bridge 11 in the hydrogen production system is connected to the power grid 12. The power grid 12 is a three-phase power grid.

[0033] It should be noted that, in Figure 1 In this diagram, each submodule is represented by an SM. Within each SM, an electrolyzer (EL) unit, a photovoltaic (PV) unit, and / or an energy storage (ES) unit are connected to the capacitor of the SM via a dedicated DC-DC converter. The electrolyzer unit, PV unit, and energy storage unit are not connected in series. Figure 1 As shown in the image; , , , , as well as Indicates inductance. Figure 1 middle , , The meter indicates the three-phase voltage of the power grid; , and The table indicates the three-phase current flowing into or out of the three-phase cascaded H-bridge 11 from the power grid; , , These represent the output voltages of the three-phase bridge arms of the three-phase cascaded H-bridge 11; , and This indicates the current in the three-phase arms of the three-phase cascaded H-bridge 11. This refers to circulating current. In a delta-connected cascaded H-bridge, circulating current exists due to factors such as the voltage and current of each phase arm. The presence of circulating current affects the power transmission, loss, and other characteristics of the system.

[0034] In other words, in the hydrogen production system described above, each arm of the three-phase cascaded H-bridge includes two types of sub-modules: a first sub-module and a second sub-module.

[0035] For example, suppose there are 8 sub-modules in each bridge arm, which may include 4 first sub-modules, each of which is connected to the electrolytic cell unit via a DC-DC converter, and 4 second sub-modules, each of which is connected to the photovoltaic unit via a DC-DC converter.

[0036] For example, suppose there are 8 sub-modules in each bridge arm, which may include 4 first sub-modules, each of which is connected to the electrolytic cell unit via a DC-DC converter, and 4 second sub-modules, each of which is connected to the energy storage unit via a DC-DC converter.

[0037] For example, suppose there are 9 sub-modules in each bridge arm, which may include 3 first sub-modules, each of which is connected to the electrolyzer unit via a DC-DC converter; and 6 second sub-modules, of which 3 second sub-modules are connected to the photovoltaic unit via a DC-DC converter, and the other 3 second sub-modules are connected to the energy storage unit via a DC-DC converter.

[0038] The system adopts a three-phase cascaded H-bridge structure, with each bridge arm consisting of multiple sub-modules connected in series. Each sub-module is connected to the electrolyzer unit, photovoltaic unit, and / or energy storage unit via a dedicated DC-DC converter. The hydrogen production system described above is highly modular, which can overcome the shortcomings of centralized or multi-port topologies with low modularity in related technologies. It allows the system to flexibly increase or decrease the number of sub-modules to expand the system capacity according to actual needs, and can significantly improve fault tolerance. For example, when a sub-module fails, only the failed sub-module needs to be dealt with, and it is not easy to affect the normal operation of the entire system.

[0039] In addition, by connecting the photovoltaic unit and / or energy storage unit to different sub-modules and then connecting the three-phase cascaded H-bridge to the power grid, the power fluctuations of the photovoltaic unit caused by sunlight and weather factors can be effectively mitigated with the help of the energy storage unit and / or the power grid. This avoids the problem of unstable input current when the traditional photovoltaic directly drives the electrolyzer system, ensuring that the electrolyzer unit receives a stable power supply, thereby improving hydrogen production efficiency and slowing down the aging of the equipment.

[0040] In some embodiments, in the hydrogen production system described above, each submodule supports three voltage output levels: positive capacitor reference voltage, negative capacitor reference voltage, and zero.

[0041] In the above embodiments, each submodule supports three levels of output: positive and negative capacitor reference voltage and zero. This enables precise adjustment of the output voltage and power of the three-phase cascaded H-bridge, improving the stability and accuracy of the electrolyzer power supply. It also enhances the system's adaptability and buffering capability to power fluctuations in the power grid, photovoltaic, and energy storage units, thereby optimizing the overall operating efficiency of the hydrogen production system.

[0042] In some embodiments, in the hydrogen production system described above, multiple submodules are full-bridge submodules, each including four power switches and one capacitor.

[0043] In the above embodiments, the use of full-bridge submodules can flexibly realize the polarity reversal and amplitude adjustment of the submodule output voltage, providing a flexible level combination capability for three-phase cascaded H-bridges, which can improve the system power regulation accuracy and fault tolerance redundancy, and ensure the stability and reliability of the power supply to the electrolytic cell.

[0044] In some embodiments, the first submodule includes a capacitor, and the electrolytic cell unit is connected to both ends of the capacitor in the first submodule via a DC-DC converter. The electrolytic cell unit is used to discharge the capacitor in the first submodule during operation.

[0045] For example, such as Figure 2 The diagram shown is a schematic of a first submodule connected to an electrolytic cell unit via a DC-DC converter. Figure 2 The first submodule includes one capacitor and four switches. Figure 2 The components are represented as S1, S2, S3, and S4, the first DC-DC converter 22, and the electrolytic cell unit 21, respectively. The electrolytic cell unit 21 is connected to both ends of a capacitor via the first DC-DC converter 22. Figure 2 During operation, the electrolytic cell unit 21 continuously discharges the capacitor of the first submodule. The first DC-DC converter 22 is a unidirectional DC-DC converter. When the capacitor voltage of the first submodule is stable, the output current ripple can be precisely controlled to supply power to the electrolytic cell unit 21, enabling the electrolytic cell unit 21 to use electrical energy to produce hydrogen, converting electrical energy into hydrogen energy. The above is as follows... Figure 2 The submodule shown here with the electrolytic cell unit can be referred to as EL-SM in the following text.

[0046] exist Figure 2 middle, The bridge arm current is the current flowing through the bridge arm of the circuit, which plays a crucial role in powering the loads such as the electrolytic cell unit. This indicates the submodule voltage, representing the output or the voltage across the terminals of that submodule. This indicates the current in the electrolyzer, through which the electrolyzer unit performs electrolytic reactions such as hydrogen production; This represents the voltage across the capacitor, which is the voltage across the capacitor. Capacitors can function as energy storage devices and voltage regulators.

[0047] In some embodiments, the second submodule includes a capacitor, and the photovoltaic unit is connected to both ends of the capacitor in the second submodule via a DC-DC converter. The photovoltaic unit is used to charge the capacitor in the second submodule during operation and to perform maximum power point tracking.

[0048] For example, such as Figure 3 The diagram shown is a schematic of a second submodule connected to a photovoltaic unit via a DC-DC converter. Figure 3 The second submodule includes one capacitor and four switches. Figure 3 The components are represented as S1, S2, S3, and S4, the second DC-DC converter 32, and the photovoltaic (PV) unit 31, respectively. The photovoltaic unit 31 is connected to both ends of the capacitor through the second DC-DC converter 32. Figure 3The photovoltaic unit 31 continuously charges the capacitor of the second submodule during operation. The second DC-DC converter 32 is a unidirectional DC-DC converter, which can achieve maximum power point tracking. (The above is as follows...) Figure 3 The submodule shown is equipped with photovoltaic units and will be referred to as PV-SM in the following text.

[0049] exist Figure 3 middle, The bridge arm current is the current flowing through the bridge arm of the circuit. This indicates the submodule voltage, representing the output voltage or the voltage across the terminals of that submodule. This represents the current in the photovoltaic unit, which is the current generated by the photovoltaic unit and flows into the subsequent circuit, reflecting the power generation capacity of the photovoltaic unit. This represents the voltage across the capacitor, which is the voltage across the capacitor. Capacitors can function as energy storage devices and voltage regulators.

[0050] In some embodiments, the second submodule includes a capacitor, and an energy storage unit is connected to both ends of the capacitor in the second submodule via a DC-DC converter. The energy storage unit is used to charge or discharge the capacitor in the second submodule.

[0051] For example, such as Figure 4 The diagram shown is a schematic of a second submodule connected to an energy storage unit via a DC-DC converter. Figure 4 The second submodule includes one capacitor and four switches. Figure 4 The components are represented as S1, S2, S3, and S4, the third DC-DC converter 42, and the energy storage (ES) unit 41, respectively. The energy storage unit 41 is connected to both ends of the capacitor through the third DC-DC converter 42. Figure 4 The third DC-DC converter 42 is a bidirectional DC-DC converter, and the energy storage unit 41 charges or discharges the capacitor in the second submodule through the bidirectional DC-DC converter. (The above is as follows...) Figure 4 The submodule shown is equipped with an energy storage unit and will be referred to as ES-SM in the following text.

[0052] exist Figure 4 middle, The bridge arm current is the current flowing through the bridge arm of the circuit. This indicates the submodule voltage, representing the output or the voltage across the terminals of that submodule. This indicates the current of the energy storage (ES) unit, reflecting the charging and discharging current of the energy storage (ES) unit; This represents the voltage across the capacitor, which is the voltage across the capacitor. Capacitors can function as energy storage devices and voltage regulators.

[0053] In some embodiments, in the hydrogen production system described above, the second submodule includes: a first target submodule and a second target submodule; the first target submodule is connected to a photovoltaic unit via a DC-DC converter; the second target submodule is connected to an energy storage unit via a DC-DC converter; the first submodule, the first target submodule, and the second target submodule are different submodules among a plurality of submodules.

[0054] In other words, in the hydrogen production system described above, each arm of the three-phase cascaded H-bridge includes three types of submodules: a first submodule, a first target submodule, and a second target submodule. For example, assume each arm has nine submodules. These may include three first submodules, each connected to an electrolyzer unit via a DC-DC converter; three first target submodules, each connected to a photovoltaic unit via a DC-DC converter; and three second target submodules, each connected to an energy storage unit via a DC-DC converter.

[0055] In the above embodiments, by subdividing the submodules into a first submodule connecting the electrolyzer unit, a first target submodule connecting the photovoltaic unit, and a second target submodule connecting the energy storage unit, and configuring suitable DC-DC converters for different submodules (unidirectional converters adapt to the unidirectional energy flow requirements of the electrolyzer unit and the photovoltaic unit, and bidirectional converters meet the bidirectional charging and discharging regulation requirements of the energy storage unit), the division of labor and coordinated operation of each unit's functions are realized. Specifically, the electrolyzer unit obtains stable electrical energy for hydrogen production through unidirectional discharge, the photovoltaic unit achieves maximum power output and supplies energy to the system through unidirectional charging, and the energy storage unit uses bidirectional conversion for flexible charging and discharging to smooth power fluctuations. These three components complement each other in a three-phase cascaded H-bridge architecture. This ensures the efficient operation of the core functions of each unit (such as maximum power point tracking of the photovoltaic system and stable current supply to the electrolyzer), improves the accuracy of system energy management through a clear energy flow path, and enhances the system's scalability and fault tolerance through a modular structure. Ultimately, in a multi-source collaborative scenario, continuous and stable power supply to the electrolyzer is achieved, improving hydrogen production efficiency and equipment lifespan.

[0056] It should be noted that the above-mentioned hydrogen production system can be flexibly expanded, supporting the configuration of the number of PV-SM, ES-SM and EL-SM as needed to improve the system's fault tolerance and scalability.

[0057] In some embodiments, the first submodule and the second submodule have the same proportion in each arm of the three-phase cascaded H-bridge.

[0058] For example, suppose a single arm of a three-phase cascaded H-bridge has 6 sub-modules, and the first sub-module is allocated to the second sub-module in a 1:1 ratio. This arm contains 3 first sub-modules and 3 second sub-modules.

[0059] For example, suppose a single arm of a three-phase cascaded H-bridge has 7 sub-modules, and the first sub-module is allocated to the second sub-module in a ratio of 4:3. This arm contains 4 first sub-modules and 3 second sub-modules.

[0060] In some embodiments, in each arm of a three-phase cascaded H-bridge, the first submodule, the first target submodule, and the second target submodule have the same proportion.

[0061] For example, suppose a single arm of a three-phase cascaded H-bridge has 9 sub-modules, and the first sub-module, the first target sub-module, and the second target sub-module are allocated in a ratio of 1:1:1. This arm contains 3 first sub-modules, 3 first target sub-modules, and 3 second target sub-modules.

[0062] For example, suppose a single arm of a three-phase cascaded H-bridge has 10 sub-modules, allocated in a ratio of 4:3:3 between the first and second sub-modules. This arm contains 4 first sub-modules, 3 first target sub-modules, and 3 second target sub-modules.

[0063] It should be noted that the number of different types of sub-modules in each arm of the three-phase cascaded H-bridge is not limited in the embodiments of this application.

[0064] In the above embodiments, by flexibly configuring the number and proportion of different types of sub-modules in each arm of the three-phase cascaded H-bridge, it supports both equal proportions to achieve functional balance and synergy, and allows asymmetrical proportions to adapt to the differences in energy supply and hydrogen production demand in actual scenarios, without limiting the upper limit of the number of sub-modules. This flexibility not only allows the system to dynamically adjust according to the actual ratio of photovoltaic installed capacity, energy storage scale, and electrolyzer hydrogen production power to adapt to diverse application scenarios, but also ensures the efficient implementation of core functions (photovoltaic energy supply, energy storage peak shaving, and stable hydrogen production) while avoiding resource waste or functional deficiencies caused by fixed configurations. This further enhances the system's practicality, scalability, and scenario adaptability, providing support for the large-scale deployment and personalized application of hydrogen production systems.

[0065] The aforementioned hydrogen production system includes a three-phase cascaded H-bridge connected in a delta configuration. Each arm of the cascaded H-bridge consists of multiple sub-modules connected in series. Among these sub-modules, the first sub-module is connected to the electrolyzer unit via a DC-DC converter, and the second sub-module is connected to a functional unit via a DC-DC converter. The functional unit includes a photovoltaic unit and / or an energy storage unit. The first and second sub-modules are different sub-modules within the larger set of sub-modules. This design allows the first sub-module to connect to the electrolyzer unit and the second sub-module to connect to the photovoltaic unit or energy storage unit, enabling independent access and control of the electrolyzer's hydrogen production load and the functional unit. This provides a structural foundation for their coordinated operation, and the modular approach facilitates future expansion and adapts to varying power demands in different scenarios.

[0066] In some embodiments, the hydrogen production system described above further includes a sampling module, which is connected to the capacitors of each submodule, the arms of the three-phase cascaded H-bridge, the electrolyzer unit, the photovoltaic unit, and the energy storage unit, respectively, for collecting the capacitor voltage, arm current, and operating parameters of each functional unit of each submodule. Each functional unit includes a photovoltaic unit or an energy storage unit.

[0067] In this hydrogen production system, the sampling module constructs a comprehensive operational parameter acquisition network through a multi-channel connection architecture. Specifically, the sampling module's acquisition end establishes physical connections with the capacitors of all sub-modules, the main body of each bridge arm, the electrolyzer unit, the photovoltaic unit, and the energy storage unit in the three-phase cascaded H-bridge: for each sub-module, it acquires the voltage signal across the capacitor in real time to monitor the energy storage status; for each bridge arm, it accurately acquires the current signal to obtain power transmission dynamics; for each electrolyzer unit and functional unit, it acquires operational parameters such as the input current and hydrogen production efficiency of the electrolyzer unit, the output voltage, current, and power parameters of the photovoltaic unit, and the charging and discharging current and state of charge (SOC) parameters of the energy storage unit. Finally, all the acquired electrical parameters and operational status data are integrated and transmitted to provide comprehensive and real-time data input for subsequent system control decisions.

[0068] The aforementioned sampling module is configured to establish a comprehensive parameter acquisition capability for the hydrogen production system. On one hand, by acquiring core electrical parameters such as submodule capacitor voltage and bridge arm current in real time, potential fault risks such as capacitor overvoltage or undervoltage and abnormal bridge arm current can be detected in a timely manner, providing data support for system fault early warning and protection, and improving operational safety. On the other hand, by accurately acquiring the operating parameters of each unit, including the electrolyzer, photovoltaic, and energy storage, the system can grasp the photovoltaic power fluctuation, energy storage charging and discharging status, and electrolyzer power supply requirements, avoiding control lag or misjudgment due to missing parameters. This lays a data foundation for subsequent control modules to achieve refined adjustment, ensuring the coordinated and efficient operation of all parts of the system.

[0069] In some embodiments, the hydrogen production system described above further includes: a control module, which is connected to the sampling module, the power switches of each submodule, and the DC-DC converter, for parsing the parameters collected by the sampling module, outputting on / off commands for the power switches in each submodule, and outputting adjustment commands for the DC-DC converters in each submodule.

[0070] In the aforementioned hydrogen production system, the control module serves as the core of decision-making and control, regulating the entire system through a bidirectional signal interaction link. At the data input end, the control module establishes a communication connection with the sampling module, receiving all parameters transmitted by the sampling module (including submodule capacitor voltage, bridge arm current, and operating parameters of each functional unit). It then analyzes these parameters using a built-in algorithm to determine the current system operating status (e.g., whether photovoltaic power is excessive, whether energy storage needs charging and discharging, and whether the electrolyzer power supply is stable). At the control output end, the control module connects to the power switches and DC-DC converters of each submodule. Based on the parameter analysis results, it outputs on / off commands to the power switches, adjusting the submodule's output level to match the bridge arm power demand. Simultaneously, it outputs adjustment commands to the DC-DC converters (e.g., adjusting the output current of the unidirectional converter and the charging / discharging mode of the bidirectional converter), achieving precise control of the energy flow of each functional unit.

[0071] The introduction of the aforementioned control modules enables the hydrogen production system to actively regulate itself, improving system stability and energy efficiency. Firstly, by analyzing sampled data and dynamically adjusting the power switch on / off state, the output characteristics of the three-phase cascaded H-bridge can be optimized in real time, offsetting the impact of photovoltaic power fluctuations on the bridge arms. This ensures a continuous and stable power supply to the electrolyzer, preventing a decrease in hydrogen production efficiency or accelerated equipment aging due to unstable power supply. Secondly, by precisely adjusting the DC-DC converter, the functions of each unit can be maximized: for example, controlling the DC-DC converter of the photovoltaic unit to achieve maximum power point tracking, improving solar energy utilization; controlling the bidirectional DC-DC converter of the energy storage unit to flexibly charge and discharge, mitigating power shortages, and preventing damage to the electrolyzer unit due to current fluctuations. Ultimately, this achieves optimal energy allocation and coordinated operation of the entire system, contributing to the efficient and reliable operation of the hydrogen production process.

[0072] In this embodiment of the application, based on the above-mentioned hydrogen production system, a power supply control method for an electrolyzer is also provided, which can improve the power supply stability of the electrolyzer.

[0073] In this embodiment, the main control objective of the electrolytic cell power supply control method is to achieve stable power supply to the EL unit, thus requiring the maintenance of stable EL-SM capacitor voltage. Simultaneously, to ensure the stability of the entire system, the capacitor voltage in all sub-modules (SMs) needs to be maintained near its rated value. Under different operating conditions, the charging and discharging states or intensities of capacitors in different SMs by the EL unit, PV unit, or ES unit vary.

[0074] For example, in operating condition (1), when the light intensity is strong and the output power of the PV unit is relatively high, , Indicates the output power of the PV unit. This indicates the output power of the electrolytic cell unit; at this time, the charging current from the PV unit to the capacitor of the PV-SM is relatively large, requiring control of the bridge arm current. He Ru Figure 3 The states of the four power switches (S1 / S2 / S3 / S4) in the PV-SM shown cause the arm current to change within one grid cycle. The energy discharged to the capacitor cancels out the energy charged by the PV unit to the capacitor. Assume the states of the power switches (S1 / S2 / S3 / S4) can... The capacitor of the PV-SM is constantly discharged and its voltage remains stable at the rated value. Then, the following formula (1) is shown:

[0075] (1)

[0076] in, Indicates the power grid cycle.

[0077] If the EL unit is to discharge the capacitor of the EL-SM with a stable discharge current (or power), then control is required. The states of the four power switches (S1 / S2 / S3 / S4) in the EL-SM ensure that within one grid cycle... The energy used to charge the capacitor offsets the energy used to discharge the capacitor from the EL unit. Assuming the states of the four power switches (S1 / S2 / S3 / S4) can... The capacitors in the EL-SM are always charged and their voltage remains stable at the rated value. Then, the following formula (2) is shown:

[0078] (2)

[0079] in, This indicates the discharge power of the EL unit.

[0080] When the output power of the PV unit is relatively high At this time, in order to maintain system power balance, the ES unit must... Charging at that power, that is... The power is used to discharge the capacitor of the ES-SM. At this time, control is required. The states of the four power switches (S1 / S2 / S3 / S4) in the ES-SM ensure that within one grid cycle... The energy used to charge the capacitor can offset the energy used to discharge the capacitor by the ES unit. Assuming the states of the power switches (S1 / S2 / S3 / S4) can... The capacitor of the ES-SM is always charged and its voltage remains stable at the rated value. Then, as shown in the following formula (3):

[0081] (3)

[0082] In addition to the above-mentioned operating conditions, the ES-SM may also have the following operating conditions:

[0083] Operating condition (2), under insufficient lighting ( ), and when the ES cell has a sufficient state of charge, the ES cell should use The power is used to charge the capacitor of the ES-SM. At this time, control is required. The states of the four power switches (S1 / S2 / S3 / S4) in the ES-SM ensure that within one grid cycle... The energy discharged to the capacitor cancels out the energy charged by the ES unit to the capacitor. Assuming the states of the power switches (S1 / S2 / S3 / S4) can... The capacitor of the ES-SM is always discharged and its voltage remains stable at the rated value. Then, the following formula (4) is shown:

[0084] (4)

[0085] Operating condition (3), under insufficient lighting ( When the ES unit's state of charge is insufficient, the grid provides energy to maintain the EL unit's power supply, while simultaneously charging the ES unit at a preset power (the ES unit discharges the capacitor of the ES-SM). Assume the preset charging power of the ES unit is... At this point, control is required. The states of the four power switches (S1 / S2 / S3 / S4) in the ES-SM ensure that within one grid cycle... The energy charged to the capacitor offsets the energy discharged by the ES unit to the capacitor. Assuming the states of the power switches (S1 / S2 / S3 / S4) can... The capacitor of the ES-SM is always discharged and its voltage remains stable at the rated value. Then, the following formula (5) is shown:

[0086] (5)

[0087] In summary, besides controlling the switching states of (S1 / S2 / S3 / S4), if it is necessary to stabilize the power supply voltage of the electrolytic cell, the bridge arm current... It needs to be large enough. In the embodiments of this application, It can be divided into three parts: the first part is the differential-mode component of the synthesized grid current, using... The second part represents the zero-sequence circulation caused by the imbalance of total energy stored in different bridge arms, expressed as... The third part represents the actively injected third harmonic circulating current, represented by... This indicates that when the grid current is low (e.g., when the power exchange between the photovoltaic-energy storage-hydrogen production system and the grid is small), the situation is different. It is also relatively small; when the three-phase energy is in steady state of equilibrium, The value is 0; therefore, if it is necessary to maintain a stable power supply to the electrolytic cell, the power supply should be adjusted according to the operating conditions. The size of the electrolytic cell power supply control method in this application embodiment is crucial.

[0088] For example, such as Figure 5 As shown, an electrolyzer power supply control method is provided. This method can be applied to the hydrogen production system shown in any of the above embodiments, and the method may include the following steps:

[0089] 501. Based on the constant power consumption of each electrolytic cell unit and the status information of the functional units in the second submodule, determine the power reference value of the electrolytic cell unit and the power reference value of the functional units.

[0090] The status information of the functional units in the second submodule may include, but is not limited to: the maximum power tracking value of the photovoltaic unit and / or the state of charge of the energy storage unit.

[0091] The constant power consumption of the aforementioned electrolyzer unit can refer to the total constant power consumption of all electrolyzer units in the hydrogen production system (hereinafter referred to as...). The maximum power point tracking (MPPT) value of the aforementioned photovoltaic (PV) units can refer to the total MPPT value of all PV units in the hydrogen production system (hereinafter referred to as ). The state of charge of the aforementioned energy storage unit refers to the total state of charge of all energy storage units in the hydrogen production system.

[0092] In some embodiments, the total constant power consumption of the electrolyzer units in the hydrogen production system can be calculated based on the number of electrolyzer units in the system and the constant power consumption of a single electrolyzer unit, and the total maximum power tracking value can be calculated based on the number of photovoltaic units in the hydrogen production system and the maximum power tracking value of each photovoltaic unit. Then, based on the total constant power consumption and the total maximum power tracking value, the power reference value of each electrolyzer unit and the power reference value of each photovoltaic unit can be determined.

[0093] In some embodiments, the total constant power consumption of the electrolyzer units in the hydrogen production system can be calculated based on the number of electrolyzer units in the hydrogen production system and the constant power consumption of a single electrolyzer unit. The total state of charge of the energy storage units in the hydrogen production system can be calculated based on the number of energy storage units in the hydrogen production system and the state of charge of each energy storage unit. Then, based on the total constant power consumption and the total state of charge, the power reference value of each electrolyzer unit and the power reference value of each energy storage unit can be determined.

[0094] In some embodiments, the second submodule of the hydrogen production system described above includes a first target submodule and a second target submodule. The first target submodule is connected to a photovoltaic unit via a DC-DC converter, and the second target submodule is connected to an energy storage unit via a DC-DC converter. The first submodule, the first target submodule, and the second target submodule are different submodules among multiple submodules.

[0095] For the second submodule of the aforementioned hydrogen production system, which includes a first target submodule and a second target submodule, the power reference values ​​of the electrolyzer unit and the functional units are determined based on the constant power consumption of the electrolyzer unit and the status information of the functional units in the second submodule. This includes determining the power reference values ​​of the electrolyzer unit, the functional units, and the power reference values ​​of the power grid based on the constant power consumption of the electrolyzer unit, the maximum power tracking value of the photovoltaic unit, and the state of charge of the energy storage unit.

[0096] In some embodiments, the power reference value of the electrolytic cell unit, the power reference value of the functional unit, and the power reference value of the power grid are determined based on the constant power consumption of the electrolytic cell unit, the maximum power point tracking value of the photovoltaic unit, and the state of charge of the energy storage unit, including but not limited to the following situations:

[0097] Case (1): If the maximum power tracking value of the photovoltaic unit is greater than the constant power consumption of the electrolytic cell unit, and the state of charge of the energy storage unit has not reached the upper limit, then the maximum power tracking value of the photovoltaic unit is used as the power reference value of the photovoltaic unit, the constant power consumption of the electrolytic cell unit is used as the power reference value of the electrolytic cell unit, the power reference value of the energy storage unit is determined based on the power reference value of the photovoltaic unit and the power reference value of the electrolytic cell unit, and the power reference value of the power grid is set to 0.

[0098] Case (2): If the maximum power tracking value of the photovoltaic unit is greater than the constant power consumption of the electrolytic cell unit, and the state of charge of the energy storage unit has reached the upper limit, then the constant power consumption of the electrolytic cell unit will be used as the power reference value of the electrolytic cell unit and the power reference value of the photovoltaic unit, the power reference value of the energy storage unit will be set to 0, and the power reference value of the power grid will be set to 0.

[0099] In response to the above situation (2), it can also be replaced by situation (2.1): If the maximum power tracking value of the photovoltaic unit is greater than the constant power consumption of the electrolyzer unit, and the state of charge of the energy storage unit has reached the upper limit, then the constant power consumption of the electrolyzer unit is used as the power reference value of the electrolyzer unit, the maximum power tracking value of the photovoltaic unit is used as the power reference value of the photovoltaic unit, and the power reference value of the energy storage unit is set to 0. Based on the power reference value of the photovoltaic unit and the power reference value of the electrolyzer unit, the power reference value of the hydrogen production system feeding power to the grid is determined.

[0100] Case (3): If the maximum power tracking value of the photovoltaic unit is less than the constant power consumption of the electrolytic cell unit and the state of charge of the energy storage unit has not reached the lower limit, then the constant power consumption of the electrolytic cell unit is used as the power reference value of the electrolytic cell unit, the maximum power tracking value of the photovoltaic unit is used as the power reference value of the photovoltaic unit, and the power reference value of the energy storage unit is determined based on the power reference value of the photovoltaic unit and the power reference value of the electrolytic cell unit. The power reference value of the power grid is set to 0.

[0101] Case (4): If the maximum power tracking value of the photovoltaic unit is less than the constant power consumption of the electrolytic cell unit, and the state of charge of the energy storage unit has reached the lower limit, then the constant power consumption of the electrolytic cell unit is used as the power reference value of the electrolytic cell unit, the maximum power tracking value of the photovoltaic unit is used as the power reference value of the photovoltaic unit, and the power reference value of the energy storage unit is set as the preset charging power. Based on the power reference values ​​of the electrolytic cell unit, the photovoltaic unit, and the energy storage unit, the power reference value of the power grid is determined.

[0102] In response to the above situation (4), it can also be replaced by situation (4.1): if the maximum power tracking value of the photovoltaic unit is less than the constant power consumption of the electrolytic cell unit, and the state of charge of the energy storage unit has reached the lower limit, then the power reference value of the energy storage unit is set to 0, and the power reference value of the power grid is determined based on the power reference value of the electrolytic cell unit and the power reference value of the photovoltaic unit.

[0103] For example, Figure 6 This is a hierarchical collaborative control framework used in a modular photovoltaic energy storage hydrogen production system. For example... Figure 6As shown, the first layer is system energy management 61, which is responsible for dynamically allocating power from the EL, PV, ES, and grid to obtain power reference values ​​for each part (as shown in Table 1 below). The second layer is DC-DC power control 62, in which the DC-DC converters connected through the EL unit, PV unit, and ES unit can accurately track power commands. The third layer is electrolytic cell stable power supply control 63, which is responsible for maintaining energy balance between bridge arms while generating circulating current references (i.e., the reference value of the total circulating current). The fourth layer is the current control 64 of the cascaded H-bridge, which includes calculating the bridge arm voltage reference value for each bridge arm based on the grid current and circulating current reference (the control method for the fourth layer can refer to the existing technology "State Space Modelling and Control Framework of the Distributed Energy Storage System based on Cascaded H-Bridge STATCOM"); the fifth layer is the bottom layer control 65, which includes controlling the state of the power switches in each SM to achieve bridge arm voltage tracking and submodule capacitor voltage balancing (the control method for the fifth layer can refer to the existing technology CN118763885A). STATCOM stands for Static Synchronous Compensator.

[0104] in, Figure 6 middle Indicates grid power. This indicates the power reference value for the electrolytic cell unit. This represents the power reference value of the photovoltaic unit. This represents the power reference value of the energy storage unit. The three-phase current of the power grid is the actual current that interacts with the power grid. This represents a reference value for the total circulating current. , , This represents the bridge arm voltage reference value, which is the target voltage command generated by the current control module. , and This represents the actual current in the bridge arm, reflecting the real-time status of the bridge arm current. This indicates the capacitor voltage of the submodule.

[0105] For example, Table 1 shows a typical energy management method for the first-level system, based on the maximum power generation of the current PV unit's maximum power tracking (MPT). ) and the constant power consumption of the EL unit ( The power allocation of different cells is determined by the relationship between the ES cells and other factors such as their state of charge. The power reference value for the ES cells is also considered. A positive signal indicates that the ES unit is being charged. A negative value indicates that the ES unit is discharging, where the power reference value of the grid is... A positive value indicates that the system is feeding power to the grid. A negative value indicates that the power grid is charging the system.

[0106] Table 1

[0107]

[0108] 502. Based on the power reference values ​​of the electrolytic cell unit and the functional unit, determine the minimum reference bridge arm current used to maintain power balance.

[0109] In some embodiments, the method of determining the minimum reference bridge arm current for maintaining power balance based on the power reference value of the electrolytic cell unit and the power reference value of the functional unit may include, but is not limited to: determining a first power reference value based on the power reference value of the electrolytic cell unit and the number of first sub-modules; determining a second power reference value based on the power reference value of the functional unit and the number of second sub-modules; and determining the minimum reference bridge arm current for maintaining power balance based on the maximum value of the first power reference value and the second power reference value, and the rated voltage of the capacitor of the sub-module.

[0110] In the above embodiments, firstly, the power reference value of the electrolytic cell unit can be matched and calculated with the number of first sub-modules connected to obtain the first power reference value that each first sub-module should bear, ensuring that the constant power consumption demand of the electrolytic cell is reasonably distributed among the dedicated sub-modules; secondly, based on the power reference value of the functional unit (photovoltaic or energy storage unit) and the corresponding number of second sub-modules, the second power reference value that each second sub-module should bear is calculated, ensuring stable and compatible output of the functional unit; finally, by comparing the first power reference value and the second power reference value, the maximum value of the two is selected, and then combined with the key parameter of the rated voltage of the capacitor of the sub-module, the minimum reference bridge arm current that can maintain the power balance of the entire system is finally determined through the correlation calculation of power and voltage, so that the minimum reference bridge arm current can meet the power demand of each unit and avoid losses and fluctuations caused by current redundancy.

[0111] In some embodiments, the second submodule in the hydrogen production system described above includes a first target submodule and a second target submodule. The first target submodule is connected to a photovoltaic unit via a DC-DC converter, and the second target submodule is connected to an energy storage unit via a DC-DC converter. The first submodule is connected to an electrolyzer unit via a DC-DC converter. The first submodule, the first target submodule, and the second target submodule are different submodules among multiple submodules. The method for determining the minimum reference bridge arm current for maintaining power balance based on the power reference value of the electrolyzer unit and the power reference value of the functional unit may include, but is not limited to:

[0112] A first power reference value is determined based on the power reference value of the electrolytic cell unit and the number of the first sub-modules; a first target power reference value is determined based on the power reference value of the photovoltaic unit and the number of the first target sub-modules; a second target power reference value is determined based on the power reference value of the energy storage unit and the number of the second target sub-modules; and a minimum reference bridge arm current for maintaining power balance is determined based on the maximum value among the first power reference value, the first target power reference value, and the second target power reference value, as well as the rated voltage of the sub-module's capacitor.

[0113] For example, the minimum effective value (RMS) of the arm current required to maintain power balance is calculated as shown in the following formula (6):

[0114] (6)

[0115] in, This represents the minimum arm current RMS value. This represents a reference value for the total power of the electrolyzer unit in a hydrogen production system. This represents a reference value for the total power of the photovoltaic units in the hydrogen production system; This represents a reference value for the total power of the energy storage unit in a hydrogen production system; This indicates the number of electrolyzer units in the hydrogen production system, i.e., the number of the first sub-modules; This indicates the number of photovoltaic units in the hydrogen production system, i.e., the number of the first target sub-modules; This indicates the number of energy storage units in the hydrogen production system, i.e., the number of the second target sub-modules. This indicates the rated voltage of the capacitor in the submodule. , , It will also be referred to as in the following text. , and .

[0116] It should be noted that when the number of the first sub-module, the first target sub-module, and the second target sub-module in each bridge arm is equal, the calculation method shown in formula (6) can be simplified to the calculation method shown in formula (7):

[0117] (7)

[0118] in, for , and The maximum value in.

[0119] 503. Based on the minimum reference bridge arm current, grid power and grid voltage peak value, determine the reference value of the actively injected third harmonic circulating current.

[0120] In some embodiments, the method for determining the reference value of the actively injected third harmonic circulating current based on the minimum reference arm current, grid power, and grid voltage peak value may include, but is not limited to: determining the grid current contribution component based on the grid power and grid voltage peak value; and determining the reference value of the actively injected third harmonic circulating current based on the minimum reference arm current and grid current contribution component value.

[0121] In the above embodiment, the first step uses grid power (reflecting the actual energy transmission demand of the grid) and peak grid voltage (reflecting the maximum fluctuation boundary of grid voltage) as inputs. Through the correlation calculation between power and voltage, the grid current contribution component is obtained. This component represents the basic current value required to meet power transmission during normal grid operation and serves as the benchmark for subsequent calculations. The second step, combined with the system's internal current demand, compares and analyzes the determined minimum reference bridge arm current with the grid current contribution component. Through difference calculation or matching verification, the reference value for actively injected third harmonic circulating current is finally determined. This method considers both the actual operating state of the grid and the power balance requirements within the system, ensuring that the injection of the third harmonic circulating current accurately adapts to the dual requirements of the grid and the system.

[0122] In some embodiments, determining the reference value of the actively injected third harmonic circulating current based on the minimum reference arm current and the grid current contribution component value may include, but is not limited to: determining the effective value of the minimum third harmonic circulating current based on the minimum reference arm current and the grid current contribution component value; determining the amplitude of the minimum third harmonic circulating current based on the effective value of the minimum third harmonic circulating current; and determining the reference value of the actively injected third harmonic circulating current based on the amplitude of the minimum third harmonic circulating current.

[0123] In the above embodiments, firstly, using the minimum reference bridge arm current and the grid current contribution component as inputs, the effective value of the minimum third harmonic circulating current is calculated through the current superposition principle or difference analysis. This effective value reflects the average intensity of the third harmonic circulating current within one cycle and is a key indicator for measuring the magnitude of the circulating current. Next, based on the conversion relationship between the effective value and amplitude of AC current, the effective value of the minimum third harmonic circulating current is converted into an amplitude, clarifying the maximum intensity of the third harmonic circulating current during fluctuations and providing a precise peak reference for subsequent circuit control. Finally, based on the amplitude of the minimum third harmonic circulating current, the reference value of the final actively injected third harmonic circulating current is determined. This ensures that the injection of the third harmonic circulating current not only meets the system power balance requirements but also effectively compensates for grid harmonics, improving power supply stability.

[0124] In some embodiments, when determining the final actively injected third harmonic circulating current reference value based on the amplitude of the minimum third harmonic circulating current, the actual operating conditions such as the system's harmonic compensation requirements and the grid voltage stability requirements can also be considered to determine the final actively injected third harmonic circulating current reference value.

[0125] For example, the RMS of the grid current contribution component can be determined based on the grid power and grid voltage peak values ​​as shown in the following formula (8):

[0126] (8)

[0127] in, This represents the peak voltage of the power grid. Indicates grid power. This represents the RMS value of the grid current contribution component.

[0128] For example, the effective value of the minimum third harmonic circulating current can be determined based on the minimum reference arm current and the contribution component of the grid current, as shown in the following formula (9):

[0129] (9)

[0130] in, This represents the effective value of the minimum third harmonic circulating current.

[0131] For example, the amplitude of the minimum third harmonic circulating current can be determined based on the effective value of the minimum third harmonic circulating current as shown in the following formula (10):

[0132] (10)

[0133] in, This represents the amplitude of the minimum third harmonic circulation current. For example, the reference value for the actively injected third harmonic circulation current can be determined based on the amplitude of the minimum third harmonic circulation current, as shown in formulas (11) and (12) below:

[0134] (11)

[0135] in, This means rounding up the amplitude of the least third harmonic circulating current; adding an extra 1A margin after rounding up gives the result. The margin can also be other values, which are not limited in the embodiments of this application.

[0136] (12)

[0137] The result calculated based on the above formula (11) This allows us to obtain a reference value for the final actively injected third harmonic circulation. .

[0138] 504. Based on the reference value of the third harmonic circulating current, determine the arm current of the three-phase cascaded H-bridge.

[0139] In some embodiments, the reference value of the third harmonic circulating current, the reference value of the zero-sequence circulating current (i.e., the reference value of the zero-sequence circulating current), and the power reference value of the power grid (which can also be converted into the three-phase current of the power grid) can be used as the basis. , and ), determine the arm currents of the three-phase cascaded H-bridge.

[0140] The zero-sequence circulation reference value is determined based on the difference in total energy between different bridge arms.

[0141] In the above embodiments, in the hydrogen production system, the first submodule connects to the electrolyzer unit, and the second submodule connects to the photovoltaic unit and / or energy storage unit. This enables independent access and control of the electrolyzer's hydrogen production load and functional units, laying the structural foundation for their coordinated operation. Then, based on the constant power consumption of the electrolyzer and the state of the functional units, the power reference values ​​for the electrolyzer unit and the functional units are determined. This ensures stable operation of the electrolyzer at a constant power, meeting the power supply stability requirements of the hydrogen production process. Simultaneously, it flexibly adapts to power fluctuations in the photovoltaic unit or the charging / discharging state of the energy storage unit, avoiding interference from these fluctuations. Furthermore, by determining the reference value for the actively injected third harmonic circulating current based on the power reference values ​​of the electrolyzer unit and the functional units, the current distribution of the three-phase cascaded H-bridge can be optimized, reducing bridge arm current fluctuations and losses, improving converter operational stability and power transmission efficiency, and ultimately enhancing the power supply stability of the electrolyzer.

[0142] In some embodiments, the method for determining the zero-sequence circulating current reference value may include, but is not limited to: determining the total energy of each bridge arm based on the sampled capacitor voltage values ​​of each submodule in each bridge arm and the capacitance values ​​of each submodule; determining the energy deviation between different bridge arms based on the difference between the total energy of any two bridge arms; inputting the energy deviation into a PI controller to convert the energy deviation into a corresponding power deviation; and obtaining the zero-sequence circulating current reference value based on the power deviation, the frequency of the power grid, and the rated line voltage of the three-phase cascaded H-bridge.

[0143] In some embodiments, determining the arm current of a three-phase cascaded H-bridge based on a reference value for the third harmonic circulating current, a reference value for the zero-sequence circulating current, and a power reference value of the power grid includes: determining a reference value for the total circulating current of the three-phase cascaded H-bridge (i.e., a reference value for the total circulating current) based on the reference values ​​for the third harmonic circulating current and the zero-sequence circulating current. Current control can be performed based on this reference value for the total circulating current and the power grid current reference value.

[0144] For example, Figure 7 This is a block diagram of a stable power supply control system for an electrolytic cell in one embodiment. For example... Figure 7 As shown in the diagram, the total energy of each bridge arm is first calculated based on the sampled voltage values ​​of all SM capacitors, and the energy deviation of the three bridge arms is then considered. The power deviation is fed into the PI controller. Then according to and The product of the two is then divided by the line voltage rating. This allows us to obtain the reference value for the zero-sequence circulation. Based on the power reference values ​​of the EL unit, PV unit, and ES unit (in Figure 7 The terms are respectively represented as , and Based on the reference values ​​for determining the actively injected third harmonic circulating current shown in the above embodiments. obtain in this way Then... and The total circulating current is obtained by adding them together. It can be used as an input for current control.

[0145] Among them, the above This represents the product of the grid's angular frequency and time, where ω is the grid's angular frequency. It is the phase signal of the zero-sequence circulating current.

[0146] in, Figure 7 As shown , and This represents the reference value of the three-phase current in the power grid. , and and the reference value of total circulating current. As an input for current control.

[0147] In some embodiments, a constant current control strategy is adopted for the DC-DC converter connected to the first submodule to adjust the output current ripple according to the power reference value of the electrolytic cell unit so that the actual power consumption of the electrolytic cell unit stably matches its power reference value.

[0148] In the above embodiments, for the first sub-module DC-DC converter connected to the electrolytic cell unit, a constant current control strategy is adopted. By monitoring the actual power consumption of the electrolytic cell in real time, the output current ripple of the converter is dynamically adjusted so that the actual power always stably matches the preset power reference value.

[0149] The aforementioned constant current control can precisely suppress the interference of current fluctuations on the electrolysis process, ensuring the stable progress of the electrolysis reaction. This not only improves electrolysis efficiency but also avoids equipment damage or product quality fluctuations caused by power deviations.

[0150] In some embodiments, for the DC-DC converter of the first target submodule, a maximum power point tracking algorithm is used to adjust the operating parameters in real time according to the power reference value of the photovoltaic unit, so as to ensure that the actual output power of the photovoltaic unit stably matches its power reference value.

[0151] In the above embodiments, for the first target submodule DC-DC converter connected to the photovoltaic unit, a maximum power point tracking algorithm is introduced. Based on the power reference value of the photovoltaic unit, the operating parameters of the converter (such as output voltage and current) are adjusted in real time so that the actual output power of the photovoltaic unit continuously matches the reference value.

[0152] The aforementioned maximum power point tracking algorithm can dynamically adapt to changes in the environment such as light and temperature, maximize the power generation potential of photovoltaic units, ensure efficient utilization of photovoltaic power, and improve the clean energy consumption rate.

[0153] In some embodiments, for the DC-DC converter of the second target submodule, the operating mode is adjusted according to the power reference value of the energy storage unit: when the power reference value of the energy storage unit corresponds to the charging demand, it switches to the charging mode; when the power reference value of the energy storage unit corresponds to the discharging demand, it switches to the discharging mode, so that the actual charging and discharging power of the energy storage unit stably matches its power reference value.

[0154] For the DC-DC converter of the second target sub-module connected to the energy storage unit, the charging and discharging demand is determined according to the power reference value of the energy storage unit: when the reference value is positive, it switches to charging mode, and when it is negative, it switches to discharging mode, so that the actual charging and discharging power stably matches the reference value.

[0155] The aforementioned flexible mode switching enables dynamic balance between energy storage units and system power, ensuring the safe operation of energy storage devices (avoiding overcharging and over-discharging) while enhancing the system's buffering capacity against power fluctuations and improving the flexibility of energy dispatch.

[0156] In some embodiments, the changes in the status information of the functional units and the changes in the actual power consumption of the electrolytic cell unit are monitored in real time; when a target condition is detected, the power reference value of the electrolytic cell unit and the power reference value of the functional unit are redefined.

[0157] In some embodiments, the target condition includes: the rate of change of the state information of the functional unit exceeds a preset range.

[0158] Among them, when the rate of change of state parameters (such as light intensity and SOC) of photovoltaic, energy storage and other units exceeds the preset range, the power reference value is triggered to readjust, which can cope with the power impact caused by drastic changes in equipment state in advance and avoid system instability.

[0159] In some embodiments, the target condition includes: the deviation between the actual power consumption of the electrolytic cell unit and the power reference value exceeds a preset range.

[0160] When the actual power consumption of the electrolytic cell deviates from the reference value beyond the allowable range, the power reference value is re-determined to correct the power deviation in a timely manner, ensuring the stability of the electrolysis process and the efficiency of energy utilization.

[0161] In some embodiments, the target conditions include: the rate of change of the status information of the functional unit exceeds a preset range, and the deviation between the actual power consumption of the electrolytic cell unit and the power reference value exceeds a preset range.

[0162] When a sudden change in the state of a functional unit occurs simultaneously with a deviation in the power of the electrolytic cell, a readjustment is triggered to prioritize the stability of the core functions of the system under complex operating conditions and reduce the risk of multiple disturbances superimposed.

[0163] In the above embodiments, the status information changes of functional units (such as photovoltaic and energy storage) and the actual power consumption fluctuations of the electrolyzer are monitored in real time. When a preset target situation is detected, the power reference values ​​of the electrolyzer and functional units are recalculated and allocated.

[0164] By dynamically adjusting the reference value, the system can quickly respond to internal and external changes (such as sudden changes in equipment status and load fluctuations), maintain overall power balance, and improve the system's robustness and adaptability.

[0165] For example, Figure 8 This is a schematic diagram of the power distribution, zero-sequence circulating current, and third harmonic circulating current under four different operating conditions in one embodiment. Figure 8 The simulation results shown verify the effectiveness of the electrolytic cell power supply control method in the embodiments of this application under four different operating conditions. These four conditions exhibit different power distributions, zero-sequence circulating currents, and third harmonic circulating currents.

[0166] Specifically, the power of the electrolytic cell unit remained stable at 1kW throughout the four operating conditions. In Condition 1 (0-0.2s), the photovoltaic unit output power was 1.5kW, the energy storage unit charged at 0.5kW, there was no grid power interaction, and the third harmonic circulating current amplitude was 9A. In Condition 2 (0.2s-0.4s), the photovoltaic unit power decreased to 0.3kW, the energy storage unit discharged at 0.7kW, the grid power was also zero, and the third harmonic circulating current amplitude decreased to 6A. In Condition 3 (0.4s-0.6s), the photovoltaic unit output power was zero, the energy storage unit charged rapidly at 2kW, the grid provided 3kW of power, and the third harmonic circulating current amplitude increased to 10A. In Condition 4 (0.6s-0.8s), the photovoltaic unit output power was zero, the energy storage unit charged at 1kW, the grid power decreased to 2kW, and the third harmonic circulating current amplitude decreased to 5A. The zero-sequence circulating current exhibits damped oscillations during sudden changes in operating conditions, while its amplitude remains at 0 in steady state, reflecting the balance of energy storage in the three-phase bridge arm.

[0167] Figure 9 , Figure 10 , Figure 11 and Figure 12 The diagram shows the bridge arm voltage, capacitor voltage, bridge arm current, and output current for operating conditions 1, 2, 3, and 4, respectively. Figure 9 , Figure 10 , Figure 11 and Figure 12The waveforms show that under different operating conditions, including energy storage charging and discharging and large power fluctuations in the grid, the bridge arm voltage and the submodule capacitor voltage can be effectively balanced, and the system operates stably.

[0168] In summary, simulations have verified that the proposed strategy can effectively stabilize power distribution under various operating conditions, ensuring the efficient and reliable operation of the modular photovoltaic energy storage hydrogen production system, demonstrating good adaptability and practical value.

[0169] 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.

[0170] In one exemplary embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 13 As shown, this computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The database stores data. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communicating with external terminals via a network. When executed by the processor, the computer program implements a power supply control method for an electrolytic cell.

[0171] Those skilled in the art will understand that Figure 13 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0172] In one exemplary embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the various processes involved in the above method embodiments.

[0173] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the various processes involved in the above method embodiments.

[0174] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the various processes involved in the method embodiments described above.

[0175] 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. When executed, the computer program 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 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, etc., and are not limited to these.

[0176] 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 specification.

[0177] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of this 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 controlling the power supply of an electrolytic cell, characterized in that, An application is made in a hydrogen production system, the system comprising a three-phase cascaded H-bridge connected in a delta configuration, each arm of which consists of multiple sub-modules connected in series. Among these sub-modules, a first sub-module connects an electrolyzer unit to its capacitor via a DC-DC converter, and a second sub-module connects a functional unit to its capacitor via a DC-DC converter. The functional unit includes a photovoltaic unit or an energy storage unit. The first and second sub-modules are different sub-modules within the plurality of sub-modules. The second sub-module includes a first target sub-module and a second target sub-module. The first target sub-module is connected to the photovoltaic unit via a DC-DC converter, and the second target sub-module is connected to the energy storage unit via a DC-DC converter. The first sub-module, the first target sub-module, and the second target sub-module are different sub-modules within the plurality of sub-modules. The three-phase cascaded H-bridge is connected to the power grid. The method includes: Based on the constant power consumption of each electrolytic cell unit and the status information of the functional units in the second submodule, the power reference value of the electrolytic cell unit and the power reference value of the functional unit are determined. Based on the power reference value of the electrolytic cell unit and the power reference value of the functional unit, the minimum reference bridge arm current for maintaining power balance is determined. Based on the minimum reference bridge arm current, grid power, and grid voltage peak value, the reference value for the actively injected third harmonic circulating current is determined. Based on the reference value of the third harmonic circulating current, the arm current of the three-phase cascaded H-bridge is determined. The step of determining the reference value of the actively injected third harmonic circulating current based on the minimum reference arm current, grid power, and grid voltage peak value includes: determining the grid current contribution component based on the grid power and grid voltage peak value; and determining the reference value of the actively injected third harmonic circulating current based on the minimum reference arm current and the grid current contribution component value. The step of determining the reference value of the actively injected third harmonic circulating current based on the minimum reference bridge arm current and the grid current contribution component value includes: determining the effective value of the minimum third harmonic circulating current based on the minimum reference bridge arm current and the grid current contribution component value; determining the amplitude of the minimum third harmonic circulating current based on the effective value of the minimum third harmonic circulating current; and determining the reference value of the actively injected third harmonic circulating current based on the amplitude of the minimum third harmonic circulating current.

2. The method according to claim 1, characterized in that, The determination of the minimum reference bridge arm current for maintaining power balance based on the power reference value of the electrolytic cell unit and the power reference value of the functional unit includes: A first power reference value is determined based on the power reference value of the electrolytic cell unit and the number of the first sub-modules; The second power reference value is determined based on the power reference value of the functional unit and the number of the second sub-modules; Based on the maximum value of the first power reference value and the second power reference value, and the rated voltage of the capacitor of the submodule, a minimum reference bridge arm current for maintaining power balance is determined.

3. The method according to claim 1 or 2, characterized in that, The determination of the arm current of the three-phase cascaded H-bridge based on the reference value of the third harmonic circulating current includes: Based on the reference values ​​of the third harmonic circulating current, the zero-sequence circulating current, and the power reference value of the power grid, the arm current of the three-phase cascaded H-bridge is determined. The zero-sequence circulating reference value is determined based on the difference in total energy between different bridge arms.

4. The method according to claim 3, characterized in that, The method for determining the zero-sequence circulating current reference value includes: The total energy of each bridge arm is determined based on the sampled capacitor voltage values ​​of each submodule in each bridge arm and the capacitance values ​​of each submodule. The energy deviation between different bridge arms is determined based on the difference between the total energy of any two bridge arms; The energy deviation is input into the PI controller and converted into a corresponding power deviation. The zero-sequence circulating current reference value is obtained based on the power deviation, the frequency of the power grid, and the line voltage rating of the three-phase cascaded H-bridge.

5. The method according to claim 1 or 2, characterized in that, The step of determining the power reference value of the electrolytic cell unit and the power reference value of the functional unit based on the constant power consumption of each electrolytic cell unit and the status information of the functional units in the second submodule includes: Based on the constant power consumption of each electrolytic cell unit, the maximum power tracking value of each photovoltaic unit, and the state of charge of each energy storage unit, the power reference value of the electrolytic cell unit, the power reference value of the functional unit, and the power reference value of the power grid are determined.

6. The method according to claim 5, characterized in that, Also includes: For the DC-DC converter connected to the first submodule, a constant current control strategy is adopted to adjust the output current ripple according to the power reference value of the electrolytic cell unit so that the actual power consumption of the electrolytic cell unit stably matches its power reference value. For the DC-DC converter of the first target submodule, the maximum power point tracking algorithm is adopted to adjust the operating parameters in real time according to the power reference value of the photovoltaic unit, so as to ensure that the actual output power of the photovoltaic unit stably matches its power reference value; For the DC-DC converter of the second target submodule, the operating mode is adjusted according to the power reference value of the energy storage unit: when the power reference value of the energy storage unit corresponds to the charging demand, it switches to the charging mode; when the power reference value of the energy storage unit corresponds to the discharging demand, it switches to the discharging mode, so that the actual charging and discharging power of the energy storage unit stably matches its power reference value.

7. A computer device, characterized in that, include: A memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the method as described in any one of claims 1 to 6.

8. A computer-readable storage medium, characterized in that, It stores a computer program thereon, which, when executed by a processor, implements the method as described in any one of claims 1 to 6.

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