Method for controlling a hydrogen production plant

Abstract

The invention relates to a method for controlling a hydrogen production plant (320), the hydrogen production plant (320) comprising at least one electrolyzer (322), which is connected to an AC voltage supply network (326) by means of a rectifier (328) of the hydrogen production plant (320), said method comprising providing at least one network requirement parameter of the AC voltage supply network (326), providing at least one plant requirement parameter of the hydrogen production plant (320), determining at least one target reactive power value and a target active power value in such a way that at least the at least one network requirement parameter and the at least one plant requirement parameter are adhered to by the hydrogen production plant (320), determining at least one rectifier actuation parameter on the basis of at least the determined target reactive power value and the determined target active power value, and actuating the rectifier (328) of the hydrogen production plant (320) using the at least one determined rectifier actuation parameter.

Description

[0001]

[0002] October 7, 2025

[0003] Method for controlling a hydrogen production plant

[0004] The invention relates to a method for controlling a hydrogen production plant. Furthermore, the invention relates to a control device and a hydrogen production plant.

[0005] Hydrogen production is becoming increasingly important today. In particular, it is assumed that hydrogen will play a key role in the transition from fossil fuels to a sustainable energy supply. Hydrogen is versatile and can be used in many ways, especially as a basis for alternative fuels and / or as a process gas.

[0006] To produce hydrogen, hydrogen production plants and systems are increasingly being built, both at onshore and offshore locations. A hydrogen production plant includes at least one electrolyzer. An electrolyzer is designed to generate hydrogen. In particular, an electrolyzer is designed to carry out (water) electrolysis. During electrolysis, a redox reaction is forced using electrical energy or power, thereby generating hydrogen (and oxygen).

[0007] In addition to at least one electrolyzer, a hydrogen production plant can include at least one auxiliary production device. This auxiliary production device (in particular, all auxiliary production devices, such as all other electrical consumers like pumps, heaters, and electric motors) of the hydrogen production plant can also be referred to as the Balance of Plant (BoP). A hydrogen production plant is typically electrically connected to an AC power supply network. This AC power supply network is designed to provide the hydrogen production plant with electrical energy or power. Since an electrolyzer is generally operated with direct current (DC), a hydrogen production plant includes a rectifier. The rectifier is connected, in particular, between the AC power supply network and the electrolyzer and converts the AC voltage into DC voltage.

[0008] In a hydrogen production plant, reactive power from the AC power grid is used due to the non-linear behavior of the connected loads. Therefore, electrolyzer systems require extensive filters and / or capacitors to compensate for this reactive power. The reactive power originates from various electrical devices, which are supplied by different vendors. In current technology, this necessitates multiple compensator devices within the hydrogen production plant and its electrical system. This, in turn, increases the complexity of the hydrogen production plant and its associated costs. Furthermore, grid operators and suppliers are demanding, among other things, support for the grid in compensating for reactive power and overcoming short-term grid faults (e.g., power surges).Fluctuations in the frequency and voltage of the power grid).

[0009] Furthermore, stability is a critical factor in the electrolyzer of a hydrogen production plant due to its considerable power and energy demands. These instabilities can lead to instability in the power grid. However, the control methods for electrolyzers known from the prior art are insufficient to guarantee stability, for example, when the rectifier operating mode changes.

[0010] HB / re 240896WO

[0011] October 7, 2025. It is known from the prior art to use a rectifier in a hydrogen production plant to convert the alternating current (AC) from the AC power supply network into the direct current (DC) required by the at least one electrolyzer, as previously described. For example, three-phase rectifiers with 1GBT (Insulated-Gate Bipolar Transistor) switches can be used to generate the DC voltage. Despite the advanced switching techniques employed by such rectifiers to maintain a favorable power factor, the (significant) electrical loads connected to the electrolyzer regularly exhibit a low power factor. A low power factor leads to undesirable harmonic distortion in the AC power supply network.

[0012] In order to reduce the problems of low or suboptimal power factor and / or harmonic distortion, hydrogen production plants are known from the prior art which include filters, dynamic reactive power compensators (also known as DRPCs) and / or static reactive power compensators (also known as SRPCs).

[0013] While these components improve the electrolyzer's power factor and, in particular, reduce unwanted harmonics, they also present significant challenges for hydrogen production plants. The plant's complexity increases considerably, leading to correspondingly higher costs. Another disadvantage is the increased space requirement due to these additional components, which is a significant drawback, especially for offshore hydrogen production sites.

[0014] Therefore, the invention aims to create a way to at least reduce the aforementioned disadvantages of the prior art and, in particular, to reduce the complexity of the hydrogen production plant and the space requirement.

[0015] HB / re 240896WO

[0016] October 7, 2025, the hydrogen production plant will be reduced, while at the same time the power factor will be improved and the unwanted harmonics reduced.

[0017] According to a first aspect of the invention, this problem is solved by a method according to claim 1 for controlling a hydrogen production plant, in particular a hydrogen production plant according to claim 14. The hydrogen production plant comprises at least one electrolyzer. The at least one electrolyzer is connected to an AC power supply network of the hydrogen production plant by means of a rectifier. The method comprises:

[0018] Providing at least one network requirement parameter of the AC power supply network,

[0019] Providing at least one plant requirement parameter for the hydrogen production plant,

[0020] Determine at least one target reactive power value and one target active power value, such that at least one grid requirement parameter and one plant requirement parameter are met by the hydrogen production plant.

[0021] Determine at least one rectifier control parameter, based at least on the determined target reactive power value and the determined target active power value, and

[0022] Controlling the rectifier of the hydrogen production plant using at least one determined rectifier control parameter.

[0023] In contrast to the prior art, the claimed method according to the invention provides a possibility by which the aforementioned disadvantages of the prior art are at least reduced and, in particular, the complexity of the hydrogen production plant and the space requirement are reduced, as well as

[0024] HB / re 240896WO

[0025] October 7, 2025, at the same time the power factor of the electrolyzer will be improved and the unwanted harmonics reduced.

[0026] In other words, the invention provides a more efficient and cost-effective compensation method. In particular, the invention provides a rectifier that supplies the at least one electrolyzer with direct current in such a way that the reactive power is simultaneously balanced, in order to maintain a nearly uniform, constant power factor for the entire hydrogen production plant. Furthermore, this improves the stability of the electrical connection between the at least one electrolyzer and the AC power supply network.

[0027] Furthermore, the proposed method allows the rectifier's remaining capacity to be adjusted, particularly during periods when (for various reasons) its full capacity is not required for hydrogen production (e.g., when wind turbine output is reduced). This capacity can then be used to compensate for reactive power in the grid. In other words, it provides support for the power grid. One of the current challenges facing the power grid is isolating the electrolyzer from the grid following potential fluctuations in frequency and / or voltage levels, which can lead to grid instability. The proposed method specifically addresses this issue.

[0028] The method according to the invention serves to control a hydrogen production plant, in particular to control at least one rectifier of the hydrogen production plant. The method is, in particular, a (at least partially) computer-implemented (control) method.

[0029] The hydrogen production plant is equipped to produce hydrogen. The hydrogen production plant can be located at an offshore site and / or

[0030] HB / re 240896WO

[0031] The onshore site will be ordered by October 7, 2025. In other words, the

[0032] A hydrogen production plant can be an onshore hydrogen production plant and / or an offshore hydrogen production plant.

[0033] According to the invention, the hydrogen production plant comprises at least one electrolyzer. The electrolyzer is specifically designed to perform (water) electrolysis. The electrolyzer is configured to generate or produce hydrogen.

[0034] Preferably, the electrolyzer can be a proton exchange membrane (PEM) electrolyzer. In particular, the electrolyzer can comprise a plurality of electrolyzer stacks. It is understood that in further embodiments of the invention, the at least one electrolyzer can alternatively or additionally be an electrolyzer of a different type, such as an alkaline water electrolyzer (AWE), a high-temperature electrolyzer, an anion exchange membrane (AEM) electrolyzer, and / or the like.

[0035] For the electrical power supply of the hydrogen production plant, the hydrogen production plant is electrically connected to an AC power supply network. According to the invention, the at least one electrolyzer is connected to the AC power supply network via a rectifier or a rectifier device. The hydrogen production plant includes the at least one rectifier.

[0036] The at least one rectifier is a controllable rectifier. Preferably, the rectifier is a three-phase rectifier (TPR). Particularly preferably, the rectifier can comprise controllable IGBTs (Insulated-Gate Bipolar Transistors). In variants of the invention, the rectifier can be a SiC (silicon carbide) rectifier.

[0037] HB / re 240896WO

[0038] October 7, 2025. According to the invention, at least one (electrical) grid requirement parameter of the AC power supply network and at least one plant requirement parameter of the hydrogen production plant are provided. The grid requirement parameter specifies, in particular, a parameter that is required by the AC power supply network for the connected hydrogen production plant. The at least one provided grid requirement parameter can be permanent and constant and / or depend on the current state of the AC power supply network.

[0039] For example, the operator of the AC power supply network can specify an (electrical) network requirement parameter that must be met by the hydrogen production plant (especially at the connection point of the hydrogen production plant with the AC power supply network).

[0040] A plant requirement parameter is, in particular, a parameter that the hydrogen production plant must fulfill during operation. Preferably, two or more different grid requirement parameters and / or two or more different plant requirement parameters can be provided. The at least one provided plant requirement parameter can be permanent and constant and / or depend on the current state of the hydrogen production plant, such as a defined quantity of hydrogen to be produced.

[0041] Based on these at least two provided parameters (values), at least one target reactive power value and one target active power value are determined according to the invention, in particular of the rectifier, preferably at the connection point of the hydrogen production plant. The target reactive power value and the target active power value (of the rectifier) ​​are thus determined in such a way that at least one grid requirement parameter and at least one plant requirement parameter are met by the hydrogen production plant or the

[0042] HB / re 240896WO

[0043] October 7, 2025. The rectifier specifications must be adhered to. In particular, the specified target reactive power and target active power values ​​will be determined in such a way that all provided parameters are met, especially by the rectifier of the hydrogen production plant.

[0044] According to the invention, at least one rectifier control parameter (value) is determined to control the rectifier, based at least on the determined target reactive power value and the determined target active power value. The at least one rectifier (in particular the IGBTs) is then controlled using the at least one determined rectifier control parameter. Controlling with the at least one determined rectifier control parameter ensures that the provided and, in particular, the specified at least two parameters are adhered to.

[0045] In particular, the method according to the invention achieves the ability of the rectifier to function as a dynamic reactive power compensator.

[0046] According to a preferred embodiment of the method according to the invention, the determination of at least the target reactive power value and the target active power value can be carried out in such a way that an active power criterion of the electrolyzer is met. This power factor can preferably be a leading power factor, in particular to improve reactive power in the power grid. The active power criterion can in particular be a defined (optimal or desired) power factor of the hydrogen production plant, especially of the electrolyzer. Preferably, the desired power factor can be selected from a defined or desired power factor range. In other words, the rectifier is controlled in such a way that the specified at least two parameters and the active power criterion are met. In particular, the active power criterion specifies a uniform, constant power factor.The electrolyzer is operated particularly with the optimized power factor.

[0047] HB / re 240896WO

[0048] October 7, 2025, while simultaneously meeting at least one network requirement parameter and at least one plant requirement parameter.

[0049] As already described, according to a further embodiment of the method according to the invention, the rectifier can comprise controllable IGBTs. Determining the at least one rectifier control parameter can include: determining as at least one rectifier control parameter at least one switching time of an IGBT (in particular, all switching times of all IGBTs), such that the angle between current and voltage of the at least one IGBT is such that the specified target reactive power value and the specified target active power value are maintained.

[0050] In particular, it has been found that the switching points of the IGBTs can be set such that the specified target reactive power value and the specified target active power value (and thus the provided parameters, and especially the active power criterion) are maintained by or at the rectifier. In variants of the invention, the rectifier can be a SiC (silicon carbide) rectifier. The preceding statements can be applied to SiC rectifiers.

[0051] According to a preferred embodiment of the method according to the invention, determining at least the target reactive power value and the target active power value can be based on a (mathematical) model of the hydrogen production plant, at least of the rectifier and the electrolyzer. Based on this model, the (optimal) target active power value and the (optimal) target reactive power value can be determined. In particular, at least the function of the electrolyzer can be represented by mathematical formulas.

[0052] HB / re 240896WO

[0053] October 7, 2025 According to a preferred embodiment of the method according to the invention, the minimum target reactive power value can be determined by measuring the power factor at a connection point of the hydrogen production plant (comprising in particular the electrolyzer and balance of power) to the power grid, in order to ensure the desired compensation. If, for example, the power grid requires reactive power, this value can be added to the target reactive power value or the latter can be modified accordingly. The required active power value, for example, can be determined based on the quantity of hydrogen intended for production.

[0054] It has been recognized that changes in voltage and / or current affect hydrogen production by the electrolyzer, particularly its efficiency. Preferably, the system boundaries of the hydrogen production plant (at least of the rectifier and the electrolyzer) can be modeled using a plurality of mathematical equations. Preferably, the model equations can additionally include at least one target equation of an optimization algorithm. In particular, this allows (in a simple manner) the at least one active power criterion to be represented in the model.

[0055] According to a further embodiment of the method according to the invention, the determination of at least the target reactive power value and the target active power value can be carried out by means of at least one method selected from the group comprising:

[0056] Linear optimization method,

[0057] Evolutionary algorithm method, and particle swarm optimization method.

[0058] In particular, at least one of the aforementioned methods can be implemented in the (mathematical) model (or its equations) in order to use the model to determine, depending on at least one plant requirement parameter and

[0059] HB / re 240896WO

[0060] By October 7, 2025, at least one grid requirement parameter must be used to determine the (optimal) target active power value and the (optimal) target reactive power value. In this context, "optimal" means, in particular, that an optimized power factor (depending on the active power criterion) is set. "Optimal" specifically means that, taking into account all conditions of the electrolyzer (e.g., hydrogen price), the available electrical power (e.g., limitations of wind energy), and the required support from the electricity grid (e.g., price and demand for reactive power), the target values ​​for the active and reactive power of the rectifier are determined.

[0061] According to a further preferred embodiment of the method according to the invention, the at least one network requirement parameter can include a (current or future) reactive power demand of the AC power supply network. The target active power value and the target reactive power value can then be determined such that the reactive power demand of the AC power supply network is met, particularly by the rectifier controlled in this way. The stability of the AC power supply network can be improved.

[0062] Alternatively or additionally, at least one network requirement parameter can include a (current or future) voltage level of the AC power supply network. The target active power and reactive power values ​​can then be determined in such a way that the voltage level of the AC power supply network is maintained. This can improve the stability of the AC power supply network.

[0063] According to a further embodiment of the method according to the invention, the at least one system requirement parameter can comprise a desired or defined operating parameter of the electrolyzer. In particular, the desired or defined operating parameter can be a quantity of hydrogen to be produced by the electrolyzer (within a defined (future) period) or a result thereof.

[0064] HB / re 240896WO

[0065] The parameter value derivable by October 7, 2025, can then be determined. This allows the target active power and reactive power values ​​to be set so that the desired operating parameters of the electrolyzer are maintained. The operation of the hydrogen production plant can then be further improved.

[0066] Furthermore, according to another preferred embodiment of the method according to the invention, the at least one plant requirement parameter can include at least one permissible operating limit parameter of the hydrogen production plant. As already described, at least one permissible operating limit parameter can be provided. This permissible operating limit parameter can preferably be represented by at least one equation in the (mathematical) model. Preferably, a plurality of permissible operating limit parameters of the hydrogen production plant can be provided. In particular, all (to be observed) permissible operating limit parameters of the hydrogen production plant can be provided. Operational reliability can be further improved.

[0067] According to a further embodiment of the method according to the invention, the at least one permissible operating limit parameter can be a minimum reactive power limit value of the rectifier and / or a maximum reactive power limit value of the rectifier. This ensures, in particular, that the rectifier is operated (only) within permissible and safe operating ranges. Alternatively or additionally, the at least one permissible operating limit parameter can be a minimum hydrogen quantity that can be generated by the electrolyzer and / or a maximum hydrogen quantity that can be generated by the electrolyzer. This ensures, in particular, that the electrolyzer is operated (only) within permissible and safe operating ranges.

[0068] As already described, according to a further embodiment of the method according to the invention, the hydrogen production plant can comprise at least one auxiliary production device. The auxiliary production device can be a

[0069] HB / re 240896WO

[0070] October 7, 2025, will be an electrical consumer, especially one needed by the electrolyzer to produce hydrogen, such as a motor, a compressor, a pump, etc.

[0071] Furthermore, the auxiliary production device can be an electrical consumer, which is required in particular by the hydrogen production plant for producing the hydrogen. For example, the at least one auxiliary production device can be a hydrogen processing device. For example, a hydrogen drying device (e.g., TSA) can be provided, configured to dry the obtained (pre-dried, but in particular still wet) hydrogen, especially to -40°C. In addition, the at least one auxiliary production device can include a hydrogen compression device, configured to compress the processed hydrogen, in particular the hydrogen dried by the hydrogen drying plant.Alternatively or additionally, at least one auxiliary production device may be an inert gas generation device, configured to generate an inert gas (preferably nitrogen), for example, to carry out a cleaning process. A cleaning device (e.g., DeOXO as a cleaning device that removes O2 by reacting with H2 to form H2O) may also be provided as an auxiliary production device.

[0072] Furthermore, the at least one auxiliary production device may include, for example, a water treatment device configured to treat the water for the at least one electrolyzer. A water treatment device may be configured to treat the water in such a way that the treated water can be used in the electrolyzer for hydrogen production. For example, the water treatment device may treat seawater for electrolysis. The water treatment device and the electrolyzer may be fluidically connected in such a way that the treated water is supplied to the electrolyzer.

[0073] HB / re 240896WO

[0074] October 7, 2025. Alternatively or additionally, an auxiliary production device may, for example, include a cooling device designed to dissipate the waste heat from the hydrogen production process. This cooling can be achieved with water or air, with water cooling being preferred. Various types of water cooling exist (e.g., hybrid cooling towers, adiabatic cooling towers, etc.). If water is required for cooling, a water treatment system may also be provided. Preferably, a water treatment system may be a seawater desalination plant with membrane-based pressure filtration. Such a seawater desalination plant may, in particular, perform reverse osmosis and electrodialysis (also known as electrodeionization (EDI)) to treat the water.This type of treatment allows seawater to be purified, particularly in an energy-efficient manner, for use in water electrolysis devices. The purified water can also be referred to as ultrapure water or "demineralized water".

[0075] It is understood that in other variants of the invention, other water treatment plants can be used alternatively or additionally, such as a seawater desalination device with thermal (vacuum) distillation.

[0076] It is further understood that, according to other variants of the invention, more or fewer (and different) auxiliary production devices may be provided. The at least one auxiliary production device (in particular all auxiliary production devices of the hydrogen production plant) can also be referred to as the Balance of Plant (BoP).

[0077] Preferably, the at least one plant requirement parameter can include a reactive power parameter value of the at least one auxiliary production device (in particular the balance of power). This ensures that the entire hydrogen production plant is taken into account when determining the target active power value and the target reactive power value.

[0078] HB / re 240896WO

[0079] October 7, 2025 According to a further embodiment of the method according to the invention, the method may comprise:

[0080] Recording the mains current and voltage, and determining the (instantaneous) active power and reactive power (at the connection point of the rectifier to the mains).

[0081] Based on the determined (instantaneous) active power and reactive power of the grid, at least one grid requirement parameter (which can also be a setpoint for the grid operator) can be determined or derived. The stability of the AC power supply network can be further improved. In particular, the (instantaneous) active power and reactive power of the grid can be determined at the rectifier's connection point to the power grid. In other words, the actual rectifier active power (value) and reactive power (value) of the hydrogen production plant can be determined. Using the determined setpoint reactive power and active power values, the actual rectifier active power and reactive power values, respectively, can be controlled.

[0082] According to a further preferred embodiment of the method according to the invention, the method may comprise:

[0083] Providing at least one protection mechanism to protect at least the rectifier from disturbances occurring in the AC power supply network.

[0084] This can prevent an unintentional shutdown of the hydrogen production plant.

[0085] HB / re 240896WO

[0086] October 7, 2025. In particular, a control device of the hydrogen production plant may include at least one protection mechanism. The protection mechanism may be designed to protect at least the rectifier from disturbances occurring in the AC power supply network. For example, in the event of a rectifier failure, at least one protection mechanism, such as a rate limiter, may be provided to protect the rectifier from disturbances (e.g., frequency deviations and / or overcurrent conditions) in the AC power supply network, and in particular to avoid unnecessary disconnections of the rectifier from the AC power supply network. This protection mechanism may be applied to a frequency setpoint to control the rate of change of frequency (RoCoF).Preferably, a qd saturation block can also be provided as a protective mechanism, which can be applied to a current setpoint. The qd saturation block can, in particular, be configured as a protective shield against possible overcurrent scenarios, for example, to ensure that the rectifier remains protected from overcurrents. Operational reliability can be further improved.

[0087] A further aspect of the invention is a control device according to claim 13 for a hydrogen production plant (particularly one described above), and in particular a hydrogen production plant according to claim 14. The hydrogen production plant comprises at least one electrolyzer. The at least one electrolyzer is connected to an AC power supply network by means of a rectifier of the hydrogen production plant. The control device comprises at least one determination module. The at least one determination module is configured to obtain at least one grid requirement parameter of the AC power supply network and at least one plant requirement parameter of the hydrogen production plant. The at least one determination module is configured to determine at least one target reactive power value and one target active power value, such that

[0088] HB / re 240896WO

[0089] By October 7, 2025, at least one grid requirement parameter and at least one plant requirement parameter must be met by the hydrogen production plant. The control device comprises at least one control arrangement. The at least one control arrangement is configured to determine at least one rectifier control parameter, based at least on the determined target reactive power value and the determined target active power value. The at least one control arrangement is configured to control the rectifier of the hydrogen production plant with the at least one determined rectifier control parameter.

[0090] The at least one control device can be at least partially formed by a data processing device. The data processing device (e.g., at least one computer) can comprise at least one processor and at least one storage medium, wherein the processor and storage medium are particularly configured for executing and / or controlling the method according to claim 1. In particular, at least the determination module can be a software module executable by the processor. Preferably, the determination module can comprise the described (mathematical) model.

[0091] A further aspect of the invention is a hydrogen production plant according to claim 14 (as described above). The hydrogen production plant comprises at least one electrolyzer. The at least one electrolyzer is connected to an AC power supply network by means of a rectifier of the hydrogen production plant. The hydrogen production plant comprises at least one control device according to claim 13 (as described above).

[0092] As described, the hydrogen production plant may preferably include at least one auxiliary production device.

[0093] Furthermore, a computer program may be provided comprising instructions which, when the computer program is executed by at least one processor of a (previously

[0094] HB / re 240896WO

[0095] The control device described on October 7, 2025, causes it to execute and / or control the procedure described above.

[0096] The computer program, in particular the instructions or program statements, can be stored in a computer program product, especially a storage medium in the form of program memory. For example, program memory is non-volatile memory such as flash memory, magnetic memory, EEPROM (electrically erasable programmable read-only memory), and / or optical memory.

[0097] Additionally, a control device (or a data processing device of the background system) can have main memory, for example, volatile or non-volatile memory, in particular random access memory (RAM), such as static RAM (SRAM), dynamic RAM (DRAM), ferroelectric RAM (FeRAM), and / or magnetic RAM (MRAM). The at least one processor of the control device (in particular, the data processing device) can, for example, store intermediate results or similar data in the main memory.

[0098] The modules described above are preferably at least partially software elements (e.g., executable code) and can be executed and / or controlled by a processor of the data processing device. It should also be noted that terms such as "first," "second," etc., do not indicate a sequence but serve primarily to distinguish between two elements, unless such a chronological order is explicitly stated.

[0099] The features of the processes, control devices, and hydrogen production plants are freely combinable. In particular, features of the description and / or the dependent claims can be combined, even by completely or partially circumventing features of the independent claims.

[0100] HB / re 240896WO

[0101] October 7, 2025 Claims, whether used alone or freely combined, must be independently inventive.

[0102] There are now numerous possibilities for designing and further developing the inventive method, the inventive control device, and the inventive hydrogen production plant. Reference is made, on the one hand, to the claims subordinate to the independent claims, and on the other hand, to the description of exemplary embodiments in conjunction with the drawing. The drawing shows:

[0103] Fig. 1 shows a schematic view of an embodiment of a control device according to the invention.

[0104] Fig. 2 shows a diagram of an embodiment of a method according to the present invention,

[0105] Fig. 3 shows a schematic view of an embodiment of a hydrogen production plant according to the invention with an embodiment of a control device according to the invention, and

[0106] Fig. 4 shows a diagram of an exemplary voltage-current curve of an electrolysis cell.

[0107] In the following, similar reference symbols are used for similar elements.

[0108] Figure 1 shows a schematic view of an embodiment of a control device 100 according to the invention for a (not shown) hydrogen production plant. The control device 100 can be at least partially formed by a data processing device. The control device 100 can comprise at least one processor 106 and at least one storage medium 108. The processor 106 and storage medium 108 are configured, in particular, for

[0109] HB / re 240896WO

[0110] October 7, 2025 Controlling and / or executing the modules / arrangements 102, 104 of the control device 100 and in particular for controlling and / or executing the method according to the invention.

[0111] The control device 100 comprises at least one determination module 102. The determination module 102 is configured to receive (e.g., via an interface not shown) at least one grid requirement parameter of the AC power supply network and at least one plant requirement parameter of the hydrogen production plant. Providing a plant requirement parameter can also include a one-time specification of a permanently valid plant requirement parameter of the hydrogen production plant and / or a permanently valid grid requirement parameter of the AC power supply network.

[0112] The determination module 102 is configured to determine at least one target reactive power value and one target active power value of the rectifier, such that at least one grid requirement parameter and at least one plant requirement parameter are met by the hydrogen production plant. For example, a mathematical model of at least the rectifier and the electrolyzer of the hydrogen production plant can be implemented in the determination module 102. At least the grid requirement parameter and the plant requirement parameter can form the input parameters (values) of the model. After execution of the model (in particular by the processor 106), the target reactive power value and the target active power value (at the connection point of the hydrogen production plant) can be determined as output parameters (values) of the model.Preferably, the model can include an executable optimization method, such as the linear optimization method, the evolutionary algorithm method, the particle swarm optimization method, and / or the like. In particular, an active power criterion in the form of a (desired) power factor with which the electrolyzer is to be operated can be provided. In particular,

[0113] HB / re 240896WO

[0114] By October 7, 2025, the determination module 102 shall be set up to determine at least one target reactive power value and one target active power value of the rectifier, such that at least one grid requirement parameter and one plant requirement parameter and the desired power factor are met by the hydrogen production plant.

[0115] Preferably, the desired power factor can be selected from a defined or desired power factor range.

[0116] The control device 100 can comprise at least one control arrangement 104. The specified target reactive power value and the specified target active power value can be provided by the determination module 102 of the control arrangement 104.

[0117] The control arrangement 104 is specifically designed to control the rectifier (not shown) based on the specified target reactive power value and the specified target active power value. The control arrangement 104 is also designed to determine at least one rectifier control parameter, based on at least the specified target reactive power value and the specified target active power value. For example, the actual reactive power value of the rectifier can be controlled by the rectifier's target reactive power value, and the actual active power value of the rectifier can be controlled by the rectifier's target active power value. Furthermore, the control arrangement 104 is designed to control the rectifier of the hydrogen production plant using the at least one determined rectifier control parameter.

[0118] Figure 2 shows a diagram of an embodiment of a method according to the present invention. The method, in particular a method that is at least partially computer-implemented, can be carried out and / or controlled, in particular, by the control device according to Figure 1. The method is, in particular, a control method for controlling a rectifier of a

[0119] HB / re 240896WO

[0120] 7 October 2025 Hydrogen production plant, wherein the hydrogen production plant comprises at least one electrolyzer which is connected to an AC power supply network by means of a rectifier of the hydrogen production plant.

[0121] In step 201, at least one grid requirement parameter of the AC power supply network is provided, as already described in detail. For example, the at least one grid requirement parameter can include a reactive power demand of the AC power supply network and / or a voltage level of the AC power supply network.

[0122] In particular, at least partially parallel to step 201, step 203 involves providing at least one plant requirement parameter for the hydrogen production plant, as already described. For example, the at least one plant requirement parameter can include a desired operating parameter of the electrolyzer, in particular a quantity of hydrogen to be produced. Alternatively or additionally, the at least one plant requirement parameter can include at least one permissible operating limit parameter of the hydrogen production plant. In particular, the at least one permissible operating limit parameter can be a minimum reactive power limit of the rectifier and / or a maximum reactive power limit of the rectifier and / or a minimum quantity of hydrogen that can be generated by the electrolyzer and / or a maximum quantity of hydrogen that can be generated by the electrolyzer.

[0123] In step 205, at least one target reactive power value and one target active power value of the rectifier are determined, in particular by a determination module, such that at least one grid requirement parameter and at least one plant requirement parameter are determined.

[0124] HB / re 240896WO

[0125] The hydrogen production plant will comply with the deadline of October 7, 2025. As described, the aforementioned model can be implemented in particular.

[0126] In step 207, at least one rectifier control parameter is determined, based at least on the determined target reactive power value and the determined target active power value, as already described in particular.

[0127] In step 209, the rectifier of the hydrogen production plant is controlled using at least one determined rectifier control parameter, as has already been described in particular.

[0128] The process can be carried out continuously.

[0129] Figure 3 shows a schematic view of an embodiment of a hydrogen production plant 320 according to the invention with a preferred embodiment of a control device 300 according to the invention. To avoid repetition, only the differences from the previous embodiments are described below, and reference is made to the previous explanations.

[0130] The hydrogen production plant 320 can be an offshore hydrogen production plant and / or an onshore hydrogen production plant. The hydrogen production plant 320 comprises at least one electrolyzer 322. The electrolyzer 322 is configured to generate hydrogen. The electrolyzer 322 can be a PEM electrolyzer, in particular with multiple stacks. Specifically, the electrolyzer 322 is configured to carry out water-based electrolysis to produce hydrogen and, as a byproduct, oxygen.

[0131] HB / re 240896WO

[0132] October 7, 2025. Furthermore, the hydrogen production plant 320 includes at least one rectifier 328. The rectifier 328 is, in particular, a three-phase rectifier and may preferably include controllable IGBTs. As already described, a SiC rectifier may alternatively be provided.

[0133] The rectifier 328 is electrically connected to an AC power supply network 326 and to at least one electrolyzer 322. The rectifier 328 is configured to supply the electrolyzer 322 with a DC voltage VEiy or a DC current kiy. The rectifier 328 can convert the AC mains voltage Vc. abc and the mains alternating current ic abc or the alternating current abc convert into the direct voltage VEiy or the direct current kiy.

[0134] Furthermore, the hydrogen production plant 320 can include at least one auxiliary production device 324, for example, at least one pump, heater, electric motor, etc. For example, a water treatment device and / or at least one hydrogen treatment device, such as a drying device and / or a compressor, can also be provided. The auxiliary production devices include, in particular, electrical consumers that may be required for the operation of the electrolyzer 322. The at least one auxiliary production device 324 (also referred to as the BoP) can be supplied with alternating voltage or alternating current, as shown in Figure 3.

[0135] The control device 300 comprises in particular the determination module 302 and the control arrangement 304. For the sake of clarity, the illustration of a processor and / or storage medium and / or the like has been omitted.

[0136] The operation of the control device 300 and in particular the hydrogen production plant 320 is explained in more detail below, in particular

[0137] HB / re 240896WO

[0138] October 7, 2025, using Figures 3 and 4. In particular, Figure 3 shows a simplified process flow diagram of the hydrogen production plant 320.

[0139] Figure 4 shows, in particular, an exemplary voltage-current characteristic of an electrolysis cell, specifically a PEM cell. As can be seen from Figure 4, an increase in current leads to a (slight) increase in the cell's voltage. Furthermore, a higher current density results in higher internal losses, which reduces efficiency. Operating the cell at a higher temperature can improve efficiency at the same current density, but it also accelerates aging and shortens the cell's lifespan. Therefore, the ideal operating temperature can be chosen to achieve a defined balance between efficiency and durability. For example, a stack temperature in the range of 60 °C can be assumed. This is particularly relevant for low-temperature electrolyzers (PEM, alkaline, or AEM). For high-temperature electrolyzers, such as SOECs, the temperature is in the range of approximately 800 °C.

[0140] The equation for the operating voltage of a PEM cell is shown in (1).

[0141] V E iy = Voc

[0142] This includes:

[0143] V Eiy the operating voltage of the PEM cell;

[0144] V oc the open-circuit voltage in the unloaded state (= 0); b the Tafel slope in relation to activation losses, which represents the voltage drop due to overcoming the activation energy in the electrochemical reactions;

[0145] R is the internal resistance, which is associated with ohmic losses caused by resistance in the electrolyte and / or other cell components;

[0146] HB / re 240896WO

[0147] October 7, 2025 m. I Eiy n the mass transport or concentration losses, where m and n are parameters associated with these losses.

[0148] The efficiency of electrolyzer 322 can be expressed using the equation in (2):

[0149] This includes: r| M ax the maximum efficiency at zero current I Eiy = 0); a and b are adjustment parameters that depend on the specific cell and operating conditions.

[0150] The equation for the hydrogen production rate of electrolyzer 322 is shown in (3). This equation shows how the rate of hydrogen consumption or hydrogen production (h) H2 ) of the direct current and depends on the number of cells (Ns) of the electrolyzer 322:

[0151] Here, h H2 the amount of hydrogen produced (in moles) per second;

[0152] F is the Faraday constant, approximately 96485 coulombs per mole of electrons.

[0153] Furthermore, the following applies in particular to the (inventive) reactive power compensation:

[0154] HB / re 240896WO

[0155] October 7, 2025

[0156] Here are S c and Spiant the apparent power of the rectifier 328 and the hydrogen production plant 320 and S BoP the apparent power of the at least one auxiliary production device 324. Therefore, the reactive power requirement of the at least one auxiliary production device 324 is in particular:

[0157] QßoP — SßoP - P PßoP [5]

[0158] Qc — C- P Pc [6]

[0159] Here, PF BoP and PF C the power factor of the at least one auxiliary production device 324 or of the rectifier 328.

[0160] Furthermore, the following network requirement parameters (of the AC power supply network 326) and / or system requirement parameters (of the electrolyzer 322 and / or the rectifier 328) can be provided or apply, for example:

[0161] The limitations or permissible operating parameters of the electrolyzer or of hydrogen production by the electrolyzer are shown in particular in equation (7):

[0162] ÜH2 -min < h H2 < h H2 (7)

[0163] The reactive power generation and active power demand of rectifier 328 are shown in particular as in equation (8). However, it has been established that there are permissible operating limit parameters for the reactive power generation of rectifier 328. In most practical scenarios, the possible reactive power generation of rectifier 328 lies between 10% and 50% of the apparent power, depending on the load characteristics. In particular, it can be assumed that the

[0164] HB / re 240896WO

[0165] October 7, 2025 Qc maximum reactive power generation ratio ( — ) of rectifier 328 equal

[0166] Sc

[0167] “RPF_max” (maximum reactive power factor) is, as shown in equation (9):

[0168] S C 2 = Qc + Pc [8]

[0169] The at least one network requirement parameter can include a reactive power requirement of the AC power supply network 326 or a permissible minimum and a maximum network reactive power limit, as shown in equation (10).

[0170] 8 — Qgrid — Qgridmax (18)

[0171] To control the electrolyzer 322 in particular, a model can preferably be implemented in the control module 302, as already described. The arrows indicate that the control module provides network requirement parameters (or network parameters) and plant requirement parameters (in particular electrolyzer parameters and rectifier parameters). Furthermore, a rectifier mode (mode 1, 2) can be provided by a local controller 354.

[0172] In particular, the proposed control system proposes two operating modes: a DC mode, which can be activated if the hydrogen production plant is shut down due to an internal fault in the electrolyzer or if hydrogen production is to be stopped; and an optimization mode, which, in addition to hydrogen production, also compensates for the reactive power of the hydrogen plant and supports the electricity grid.

[0173] Changes in voltage and current affect efficiency and also hydrogen production, as described above.

[0174] HB / re 240896WO

[0175] October 7, 2025. Equations, in particular, form the model and can be the limits and the target equation of the optimization algorithm.

[0176] As previously mentioned, the active power or power factor can preferably be optimized using an active power criterion. The equations mentioned provide a (detailed) model for predicting the voltage, efficiency, and hydrogen production in the electrolyzer 322 under various operating conditions that can be provided. The efficiency, voltage, and current of the electrolyzer 322 can represent the target equation of the optimization algorithm. Similarly, hydrogen production can be a constraint of the optimization algorithm, as shown in Equation 7.

[0177] In particular, the method according to the invention achieves that the reactive power of the hydrogen production plant 320 and also the grid reactive power (Qgrid) are balanced by the reactive power generation of the electrolyzer rectifier 328 (Qc). Equations 4 to 6 serve this purpose in particular. Since the apparent power (Sc) of the rectifier 328 is limited, equation 9 can be used as a constraint in the model.

[0178] As previously described, Figure 3 shows a preferred control structure. Specifically, it illustrates a cascaded control of rectifier 328 with the proposed two operating modes (mode 1, 2) and the control of the intermediate circuit voltage of a DC-DC converter. It should be noted that parameters marked with * represent setpoint values, and those without * represent actual parameter values. The main control blocks are, in particular, the following:

[0179] Power control:

[0180] HB / re 240896WO

[0181] October 7, 2025 The current controller 344 regulates the output current i d of the rectifier 328 based on the setpoints determined by the external AC voltage control. The output of the current control loops v^° is converted into the abc coordinate system using the angle 0* to generate the modulation signal (PWM signal (see reference 352)). 0* is the electrical setpoint angle and is used in particular for the conversion into the abc frame. co*c is the angle setpoint frequency. 0*c = Jco*c dt. 0* c is the angular displacement.

[0182] As can be seen, this depends on the specified target active power value P*c of the rectifier 328 and, in particular, on a specific target voltage V*Eiy of the rectifier 328. The actual active power Pc of the rectifier 328 (as well as the actual voltage Vmy of the rectifier 328 and the actual reactive power Qc of the rectifier 328) can be calculated, in particular, using the calculation module 346 (see especially reference numeral 356).

[0183] In particular, the actual active power Pc of rectifier 328 is regulated to the specified target active power value P*c. Likewise, the actual reactive power Qc of rectifier 328 is regulated to the specified target active power value Q*c, and the actual voltage Vmy of rectifier 328 is regulated to the specified target voltage value V*Eiy.

[0184] It should be noted that dqO is the rotating setpoint and abc is the transformation to the stationary three-phase system. k P , k q and Pl vThese are the gains for the voltage-reactive power characteristic, the reactive power characteristic, and the P-voltage-frequency characteristic. As already described, P c and Q c The active power demand and reactive power generation of the rectifier 328. The typical response time of the current control is a few milliseconds.

[0185] AC voltage regulation:

[0186] HB / re 240896WO

[0187] October 7, 2025 The external AC voltage regulator 342 adjusts the output voltage v^ d The rectifier 328 responds according to the setpoints determined by the reactive power. The time response of the voltage control is typically at least ten times slower than that of the current control.

[0188] Performance management:

[0189] The power management block or determination module 302 receives critical network parameters and limits, including in particular the reactive power requirement of the AC power supply network 326 and / or the voltage level, as well as the operating parameters and limitations of the electrolyzer 322 and the rectifier 328, as has already been described in particular.

[0190] By employing at least one optimization method, such as a genetic algorithm, the determination module 302 is specifically tasked with determining the optimal setpoints for active power (P*c) and reactive power (Q*c), as previously described. Additionally, the operating mode for the rectifier 328 can be determined. The primary objective of the optimization process can be to maximize financial gains by optimizing hydrogen production and selling reactive power to the grid, while taking into account the limitations.

[0191] Load management:

[0192] This is the optimization algorithm that lies between the local control 354 of the electrolyzer 322 and the control of the rectifier 328. At this control level, the setpoint of the active power and the reactive power of the rectifier 328 is adjusted with respect to the parameters and limit values ​​of the rectifier 328, the AC power supply network 326 and the electrolyzer 322.

[0193] HB / re 240896WO

[0194] October 7, 2025 Error operation:

[0195] To protect the rectifier 328 from disturbances in the AC power supply network 326 and also to prevent unnecessary disconnections from the

[0196] To avoid problems with the AC power supply network 326 – where frequency deviations and overcurrent conditions could occur – at least two protective mechanisms are provided. A rate limiter 350 is applied to the frequency reference to control the rate of change of frequency (RoCoF). Additionally, a qd saturation block 348 is applied to the current reference, which acts as a protective shield against potential overcurrent scenarios and ensures that the rectifier 328 remains protected.

[0197] HB / re 240896WO

[0198] October 7, 2025 Reference list:

[0199] 100 Control device

[0200] 102 Determination module

[0201] 104 Control order

[0202] 106 processor

[0203] 108 storage devices

[0204] Step 201

[0205] Step 203

[0206] Step 205

[0207] Step 207

[0208] Step 209

[0209] 300 control device

[0210] 302 Determination module

[0211] 304 Control order

[0212] 320 hydrogen production plant

[0213] 322 Electrolyzer

[0214] 324 Auxiliary production device

[0215] 326 AC power supply network

[0216] 328 rectifiers

[0217] 342 AC voltage regulation

[0218] 344 Current control

[0219] 346 Calculation module

[0220] 348 Saturation block

[0221] 350 installment limiter

[0222] 352 PWM block

[0223] 354 Control

[0224] 356 Data entry and calculation block

[0225] HB / re 240896WO

[0226] October 7, 2025

Claims

October 7, 2025 Patent claims 1. Method for controlling a hydrogen production plant (320), wherein the hydrogen production plant (320) comprises at least one electrolyzer (322) which is connected to an AC power supply network (326) by means of a rectifier (328) of the hydrogen production plant (320), comprising: providing at least one network requirement parameter of the AC power supply network (326), Providing at least one plant requirement parameter of the hydrogen production plant (320), determining at least one target reactive power value and one target active power value such that at least one grid requirement parameter and one plant requirement parameter are met by the hydrogen production plant (320), determining at least one rectifier control parameter based at least on the determined target reactive power value and the determined target active power value, and controlling the rectifier (328) of the hydrogen production plant (320) with the at least one determined rectifier control parameter.

2. Method according to claim 1, wherein the determination of at least the target reactive power value and the target active power value is carried out in such a way that at least one defined active power criterion of the electrolyzer (322) is met.

3. A method according to claim 1 or 2, wherein the rectifier (328) comprises controllable IGBTs, and the determination of the at least one rectifier control parameter comprises: Determine, as at least one rectifier control parameter, at least one switching point of an IGBT, such that the angle between current and voltage of the at least one IGBT is such that the specified target reactive power value and the specified target active power value are maintained.

4. Method according to one of the preceding claims, wherein the determination of at least the target reactive power value and the target active power value is based on a model of at least the rectifier (328) and the electrolyzer (322), in particular the hydrogen production plant (320).

5. A method according to any of the preceding claims, wherein the determination of at least the target reactive power value and the target active power value is carried out by means of at least one method selected from the group comprising: Linear optimization method, evolutionary algorithm method, and particle swarm optimization method.

6. Method according to one of the preceding claims, wherein the at least one grid requirement parameter comprises a reactive power requirement of the AC power supply network, and / or the at least one grid requirement parameter comprises a voltage level of the AC power supply network.

7. Method according to one of the preceding claims, wherein the at least one plant requirement parameter comprises a desired operating parameter of the electrolyzer (322), in particular a quantity of hydrogen to be produced. HB / re 240896WO October 7, 2025 8. Method according to one of the preceding claims, wherein the at least one plant requirement parameter comprises at least one permissible operating limit parameter of the hydrogen production plant (320).

9. Method according to claim 8, wherein the at least one permissible operating limit parameter is a minimum generable reactive power limit of the rectifier (328) and / or a maximum generable reactive power limit of the rectifier (328), and / or the at least one permissible operating limit parameter is a minimum generable amount of hydrogen of the electrolyzer (322) and / or a maximum generable amount of hydrogen of the electrolyzer (322).

10. Method according to one of the preceding claims, wherein the hydrogen production plant (320) comprises at least one auxiliary production device (324) comprising at least one plant requirement parameter and a reactive power parameter value of the at least one auxiliary production device (324).

11. Method according to any of the preceding claims, further comprising: detecting the mains current and the mains voltage, and Determining the active power and reactive power of the network.

12. Method according to any of the preceding claims, further comprising: providing at least one protection mechanism for protecting at least the rectifier (328) from disturbances occurring in the AC power supply network (326). HB / re 240896WO October 7, 2025 13. Control device (100, 300) for a hydrogen production plant (320), wherein the hydrogen production plant (320) comprises at least one electrolyzer (322) which is connected to an AC power supply network (326) by means of a rectifier (328) of the hydrogen production plant (320), comprising: at least one determination module (102, 302), configured to obtain at least one grid requirement parameter of the AC power supply network (326) and at least one plant requirement parameter of the hydrogen production plant (320), wherein the determination module (102, 302) is configured to determine at least one target reactive power value and one target active power value, such that at least the at least one grid requirement parameter and the at least one plant requirement parameter are complied with by the hydrogen production plant (320), and at least one control arrangement (104, 304).set up to determine the rectifier control parameters, based at least on the specified target reactive power value and the specified, Target active power value, wherein the control arrangement (104, 304) is set up to control the rectifier (328) of the hydrogen production plant (320) with the at least one determined rectifier control parameter.

14. Hydrogen production plant (320), comprising: at least one electrolyzer (322) which is connected to an AC power supply network (326) of the hydrogen production plant (320) by means of a rectifier (328), and at least one control device (100, 300) according to claim 13. HB / re 240896WO October 7, 2025

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