A power distribution method and system for an ALK-PEM electrolyzer hydrogen production system

Abstract

The present invention belongs to the technical field of hydrogen production from renewable energy, and specifically relates to a power distribution method and system for an ALK-PEM electrolyzer hydrogen production system, comprising: obtaining the operating characteristics of an ALK electrolyzer and a PEM electrolyzer, and constructing an ALK-PEM electrolyzer combined hydrogen production system; based on the start-stop characteristics of the electrolyzers of the constructed ALK-PEM electrolyzer combined hydrogen production system, considering the second-level start-stop characteristics of the PEM electrolyzer, adopting a double-layer rotation operation mode of an electrolyzer array to determine the operating mode of the electrolyzers of the hydrogen production system; according to the determined electrolyzer operating mode, with the goal of maximizing the net benefit of the hybrid electrolyzer hydrogen production system, constructing an optimal power distribution model that takes into account the start-stop of the electrolyzers; and solving the constructed optimal power distribution model to complete the power distribution of the ALK-PEM electrolyzer hydrogen production system.

Description

Technical Field

[0001] The present invention belongs to the technical field of renewable energy hydrogen production, and in particular relates to a power distribution method and system for an ALK-PEM electrolyzer hydrogen production system. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] With the increasing depletion of fossil energy and the intensifying problem of global warming, hydrogen production through water electrolysis using renewable energy sources such as wind and photovoltaic power has become a key means of achieving a low-carbon transition in the energy sector. Currently, the more mature water electrolysis hydrogen production technologies mainly include alkaline (ALK) electrolysis and proton exchange membrane (PEM) electrolysis. ALK electrolyzers offer large capacity and low cost, but they suffer from slow dynamic response and poor adaptability to renewable energy fluctuations, presenting certain drawbacks. PEM electrolyzers offer high hydrogen production efficiency and can respond to fluctuating power sources in seconds, effectively addressing the fluctuating and intermittent nature of renewable energy generation. However, their cost is relatively high. ALK-PEM combined hydrogen production can leverage these strengths and overcome their weaknesses, significantly improving the hydrogen production system's ability to absorb renewable energy. Therefore, how to fully exploit the potential of combined hydrogen production based on the ALK-PEM's second-level operational characteristics and develop an optimal power allocation strategy for the system is a key approach to improving renewable energy absorption.

[0004] At present, ALK electrolyzers occupy a mainstream position in off-grid hydrogen production systems due to their mature technology, low cost, and relatively simple operation and maintenance. Relevant literature proposes an operation strategy for a new energy hydrogen production system based on the start-stop characteristics of alkaline electrolyzers, which realizes the coordinated operation of multiple electrolyzers and reduces the number of start-stop times of electrolyzers; relevant studies consider the efficiency characteristics and start-stop characteristics of alkaline electrolyzers, and propose a multi-ALK electrolyzer switching scheduling strategy for off-grid wind power hydrogen production based on the Pelican optimization algorithm; relevant scholars consider the frequent operation of electrolyzer switches caused by the volatility of wind power, and propose a multi-objective rolling optimization control strategy based on wind power output prediction; to balance the operating status of each electrolyzer, relevant studies propose an ALK electrolyzer array optimization control strategy based on the rotation idea; the combined operation characteristics of multiple electrolyzers can be analyzed, and a double-layer rotation coordinated operation strategy for multiple ALK electrolyzers is proposed, but the existing technology does not provide the corresponding precise mathematical expression; in summary, the existing relevant technologies have verified that the new energy absorption capacity can be effectively improved by considering the start-stop characteristics and efficiency characteristics of ALK electrolyzers, but the response speed is slow and the operating efficiency needs to be improved.

[0005] PEM electrolyzers have shown strong competitiveness with their advantages such as high efficiency, fast response, high current density, low operating temperature and high-purity hydrogen, and have become a research focus in the field of electrolytic hydrogen production. The efficient consumption of new energy can be promoted by optimizing the operation of electric-hydrogen hybrid energy storage considering the dynamic efficiency characteristics of PEM electrolyzers. Considering the operational safety characteristics and the pressure characteristics of the electrolyzer, related studies have proposed a method for optimizing the operation of PEM electrolysis hydrogen production systems based on pressure control. The relationship between the key factors affecting the electrolyzer was analyzed, and the power-temperature adaptive control optimization strategy was used to improve the hydrogen production efficiency of the system. Taking into account the power-efficiency characteristics of PEM, low-carbon optimization of the coordination of green hydrogen and blue hydrogen in the integrated energy system was carried out. However, related studies have verified that PEM electrolyzers have better absorption capacity for intermittent new energy and higher hydrogen production efficiency, but have not comprehensively considered the characteristics of PEM electrolyzers to formulate reasonable and effective power allocation strategies.

[0006] In summary, the performance of ALK and PEM electrolyzers in green electricity hydrogen production has been explored, but neither of them considers the use of the different characteristics of ALK and PEM electrolyzers for synergistic hydrogen production. At the same time, the start-stop strategy is relatively rough, which may lead to energy waste and fail to fully utilize the advantages of the electrolyzer, limiting the flexibility and economy of hydrogen production. Considering the different operating characteristics of the two types of electrolyzers and fully utilizing their respective advantages provides a new approach for electrolysis hydrogen production technology in dealing with the volatility of renewable energy. Existing technologies can verify that ALK-PEM combined hydrogen production can significantly improve the system's hydrogen production efficiency and the utilization rate of wind and solar resources, but the scheduling time scale is roughly hourly or 5 minutes. This coarse-grained expression is easy to build and solve the model, but in fact, the PEM electrolyzer has a second-level response characteristic and can be started and stopped in seconds. If it is not finely characterized, some scheduling space is easily lost, resulting in insufficient exploration of its hydrogen production flexibility. Summary of the Invention

[0007] To solve the above problems, the present invention proposes a power allocation method and system for an ALK-PEM electrolyzer hydrogen production system, taking into account the second-level start-stop characteristics of the PEM electrolyzer, and comprehensively considering the power-efficiency characteristics, start-stop characteristics of ALK and PEM electrolyzers and the second-level response speed characteristics of the PEM electrolyzer, so as to fully tap the hydrogen production potential of its fast-response flexibility resources, thereby expanding the dispatchable space and improving the hydrogen production efficiency.

[0008] According to some embodiments, a first solution of the present invention provides a power distribution method for an ALK-PEM electrolyzer hydrogen production system, which adopts the following technical solution:

[0009] A power distribution method for an ALK-PEM electrolyzer hydrogen production system, comprising:

[0010] Obtain the operating characteristics of ALK electrolyzers and PEM electrolyzers and build an ALK-PEM electrolyzer combined hydrogen production system;

[0011] Based on the start-stop characteristics of the electrolyzers in the constructed ALK-PEM electrolyzer combined hydrogen production system, and considering the second-level start-stop characteristics of the PEM electrolyzer, the operation mode of the electrolyzers in the hydrogen production system is determined by adopting a double-layer rotation operation mode of the electrolyzer array.

[0012] Based on the determined electrolyzer operation mode, with the goal of maximizing the net profit of the hybrid electrolyzer hydrogen production system, an optimal power allocation model taking into account the start and stop of the electrolyzer is constructed;

[0013] Solve the constructed optimal power allocation model and complete the power allocation of the ALK-PEM electrolyzer hydrogen production system.

[0014] As a further technical limitation, the adopted double-layer rotation operation mode of the electrolytic cell array is that the upper layer adopts the principle of first start and first shutdown, last start and last shutdown to balance the working hours of different electrolytic cells, and the lower layer performs array rotation operation according to the operating conditions of the electrolytic cell single hydrogen production.

[0015] Furthermore, the operating conditions of the electrolyzer unit for hydrogen production include at least a shutdown operating state, a high-efficiency operating state, a rated operating state, an overload operating state, and a fluctuating operating state.

[0016] As a further technical limitation, the objective function of the constructed optimal power allocation model taking into account the start and stop of the electrolyzer is Wherein, F is the net income of the hybrid electrolyzer hydrogen production system; The income from selling hydrogen for the hybrid electrolyzer hydrogen production system; C op is the operating cost of ALK electrolyzer and PEM electrolyzer; C on is the operating cost of the hybrid electrolyzer hydrogen production system; C off is the shutdown cost of the hybrid electrolyzer hydrogen production system; C curt Penalty costs for wind and solar curtailment in hybrid electrolyzer hydrogen production systems.

[0017] As a further technical limitation, the constraints of the constructed optimal power allocation model taking into account the start and stop of the electrolyzer include at least power balance constraints, ALK-PEM electrolyzer output constraints, ALK electrolyzer fluctuating power constraints, PEM electrolyzer fluctuating power constraints, ALK-PEM electrolyzer minimum start and stop time constraints, ALK-PEM electrolyzer array operation constraints and ALK-PEM electrolyzer upper array rotation start and stop constraints.

[0018] As a further technical limitation, the operating characteristics of the ALK electrolyzer and PEM electrolyzer obtained include at least the power-efficiency curve, electrolyzer single cell capacity, electrolyzer regulation performance, operating cost, start-stop characteristics and second-level response characteristics.

[0019] According to some embodiments, a second solution of the present invention provides a power distribution system for an ALK-PEM electrolyzer hydrogen production system, which adopts the following technical solutions:

[0020] A power distribution system for an ALK-PEM electrolyzer hydrogen production system, comprising:

[0021] an acquisition module configured to acquire operating characteristics of the ALK electrolyzer and the PEM electrolyzer and construct an ALK-PEM electrolyzer combined hydrogen production system;

[0022] A determination module configured to determine the operation mode of the electrolyzers of the hydrogen production system based on the start-stop characteristics of the electrolyzers of the constructed ALK-PEM electrolyzer combined hydrogen production system, taking into account the second-level start-stop characteristics of the PEM electrolyzers, and adopting a double-layer rotation operation mode of the electrolyzer array;

[0023] A construction module is configured to construct an optimal power allocation model taking into account the start and stop of the electrolyzer according to the determined electrolyzer operation mode and with the goal of maximizing the net profit of the hybrid electrolyzer hydrogen production system;

[0024] The solution module is configured to solve the constructed optimal power allocation model to complete the power allocation of the ALK-PEM electrolyzer hydrogen production system.

[0025] According to some embodiments, a third solution of the present invention provides a computer-readable storage medium, which adopts the following technical solution:

[0026] A computer-readable storage medium stores a program thereon, which, when executed by a processor, implements the steps of a power distribution method for an ALK-PEM electrolyzer hydrogen production system as described in the first embodiment of the present invention.

[0027] According to some embodiments, a fourth solution of the present invention provides an electronic device, which adopts the following technical solution:

[0028] An electronic device includes a memory, a processor, and a program stored in the memory and running on the processor. When the processor executes the program, it implements the steps of the power distribution method of an ALK-PEM electrolyzer hydrogen production system as described in the first embodiment of the present invention.

[0029] According to some embodiments, a fifth solution of the present invention provides a computer program product, which adopts the following technical solution:

[0030] A computer program product includes software code, wherein the program in the software code executes the steps in the power distribution method of an ALK-PEM electrolyzer hydrogen production system as described in the first embodiment of the present invention.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The present invention takes into account the second-level start-stop characteristics of the PEM electrolyzer, and comprehensively considers the power-efficiency characteristics, start-stop characteristics and second-level response speed characteristics of the ALK and PEM electrolyzers, so as to fully tap the hydrogen production potential of its fast-response flexibility resources, thereby expanding the dispatchable space and improving the hydrogen production efficiency.

[0033] The present invention proposes an electrolyzer mathematical model that takes into account the second-level start-stop characteristics of PEM. Drawing on the start-stop expression ideas of traditional thermal power units, and combining the double-layer array rotation operation mode of hybrid electrolyzers, the start-stop constraints of ALK-PEM electrolyzers and the rotation constraints of hybrid electrolyzer arrays are refined to fully tap the flexibility of the combined hydrogen production system and improve the overall service life of the system.

[0034] The present invention proposes the optimal power distribution of the ALK-PEM electrolyzer, comprehensively considering key factors such as the power-efficiency curves, regulation performance, and capacity of the two electrolyzers. At the same time, based on the segmented intervals of hydrogen production power, a power distribution strategy for the highest efficiency operation mode of the ALK-PEM electrolyzer and a refined power dynamic adjustment mechanism taking into account the characteristics of the electrolyzer are formulated, so as to further improve the overall efficiency of the electrolyzer system while ensuring the maximum absorption of new energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The drawings constituting a part of the specification of this embodiment are used to provide a further understanding of this embodiment. The schematic embodiments and descriptions of this embodiment are used to explain this embodiment and do not constitute an improper limitation on this embodiment.

[0036] Figure 1 This is a flow chart of a power allocation method for an ALK-PEM electrolyzer hydrogen production system according to an embodiment of the present invention;

[0037] Figure 2 This is an architecture diagram of an ALK-PEM electrolysis hydrogen production system according to an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of the structure of the ALK electrolytic cell in Example 1 of the present invention;

[0039] Figure 4 This is a power-efficiency curve of the ALK electrolyzer in Example 1 of the present invention;

[0040] Figure 5This is a schematic diagram of the structure of a PEM electrolyzer in Example 1 of the present invention;

[0041] Figure 6 This is a power-efficiency curve of the PEM electrolyzer in Example 1 of the present invention;

[0042] Figure 7 A flow chart of a power allocation strategy for a maximum efficiency operation mode according to an embodiment of the present invention;

[0043] Figure 8 Schematic diagram of the rotational startup operation mode of the upper array of the electrolytic cell in the first embodiment of the present invention;

[0044] Figure 9 Schematic diagram of the rotational shutdown operation mode of the upper array of the electrolytic cell in Example 1 of the present invention;

[0045] Figure 10 Schematic diagram of the rotation operation mode of the lower array of electrolytic cells in Example 1 of the present invention;

[0046] Figure 11 This is a graph showing wind and solar power prediction curves for each typical day in the first embodiment of the present invention;

[0047] Figure 12 Schematic diagram of wind and solar power output and electrolysis hydrogen production power under different power allocation schemes according to an embodiment of the present invention;

[0048] Figure 13 This is a comparison chart of hydrogen production power at the second level and the 5-minute level in Example 1 of the present invention;

[0049] Figure 14 This is a diagram showing the wind and solar power output and the operating status of the electrolyzer array in the first embodiment of the present invention;

[0050] Figure 15 This is a diagram showing the rotation operation status of the upper array of the ALK electrolytic cell in the first embodiment of the present invention;

[0051] Figure 16 This is a diagram showing the rotation operation status of the lower array of the PEM electrolyzer in Example 1 of the present invention;

[0052] Figure 17 This is a structural block diagram of a power distribution system of an ALK-PEM electrolyzer hydrogen production system in Example 2 of the present invention. DETAILED DESCRIPTION

[0053] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0054] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0055] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0056] In the present invention, terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", "bottom", etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present invention, and do not specifically refer to any part or element in the present invention, and should not be understood as limiting the present invention.

[0057] In the present invention, terms such as "fixed connection," "connected," and "connection" should be interpreted broadly to mean a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediary. Relevant researchers or technicians in this field may determine the specific meanings of these terms in the present invention based on specific circumstances, and they should not be construed as limitations of the present invention.

[0058] In the absence of conflict, the embodiments of the present invention and the features thereof may be combined with each other.

[0059] Example 1

[0060] The first embodiment of the present invention introduces a power distribution method for an ALK-PEM electrolyzer hydrogen production system.

[0061] like Figure 1 A power distribution method for an ALK-PEM electrolyzer hydrogen production system is shown, comprising:

[0062] Obtain the operating characteristics of ALK electrolyzers and PEM electrolyzers and build an ALK-PEM electrolyzer combined hydrogen production system;

[0063] Based on the start-stop characteristics of the electrolyzers in the constructed ALK-PEM electrolyzer combined hydrogen production system, and considering the second-level start-stop characteristics of the PEM electrolyzer, the operation mode of the electrolyzers in the hydrogen production system is determined by adopting a double-layer rotation operation mode of the electrolyzer array.

[0064] Based on the determined electrolyzer operation mode, with the goal of maximizing the net profit of the hybrid electrolyzer hydrogen production system, an optimal power allocation model taking into account the start and stop of the electrolyzer is constructed;

[0065] Solve the constructed optimal power allocation model and complete the power allocation of the ALK-PEM electrolyzer hydrogen production system.

[0066] This embodiment aims to improve the utilization rate of renewable energy power generation and the efficiency of hydrogen production by hybrid electrolyzers in the process of green electricity hydrogen production. Figure 2 The ALK-PEM electrolyzer combined hydrogen production system architecture is shown. Specifically, wind and photovoltaic power are used as power sources for water electrolysis to provide energy support for the hydrogen production system. Secondly, in the first stage, a power allocation strategy is developed based on the optimal power-efficiency operation of the ALK-PEM hybrid electrolyzer, taking into account the power-efficiency curves, regulation performance, operating costs, unit capacity, and the second-level startup and shutdown and response characteristics of the PEM electrolyzer. Next, in the second stage, a mathematical model of the ALK-PEM electrolyzer's operating characteristics is derived for five operating states: shutdown, maximum efficiency, rated operation, overload operation, and fluctuating power. Based on this model, the operating state of each electrolyzer is determined. This two-stage allocation strategy fully considers the economic efficiency and dynamic operating characteristics of each device, leveraging the complementary advantages of ALK and PEM electrolyzers. Finally, a two-tiered hybrid electrolyzer array rotation operation is adopted, with the upper tier determining the electrolyzer startup and shutdown sequence and the lower tier performing the electrolyzer rotation sequence, thereby extending the overall service life of the ALK-PEM electrolyzer system. The developed optimal power allocation strategy for ALK-PEM electrolyzer combined hydrogen production significantly improves the absorption level of wind and solar energy and hydrogen production efficiency by efficiently converting renewable energy into clean hydrogen energy.

[0067] In this embodiment, the structure of the ALK electrolytic cell is as follows: Figure 3 As shown, it consists of electrodes, electrolyte and diaphragm. The reaction expression of the electrolysis process is Combined with the electrochemical model parameters of the alkaline electrolytic cell shown in Table 1, the empirical equation can be obtained:

[0068]

[0069] η ALK =η ALK,U η ALK,F (3)

[0070]

[0071] Among them, η ALK,U is the voltage efficiency of ALK electrolyzer; U ALK,th and U ALK,revare the thermoneutral voltage and reversible voltage of the ALK electrolyzer, respectively; r1, r2, d1 and d2 are constants related to the ohmic resistance of the electrolyzer, respectively; s, t1, t2 and t3 are constants related to the reaction overpotential, respectively; T ALK is the rated operating temperature of the ALK electrolyzer; P and I are the pressure and current of the electrolyzer, respectively; A is the electrode surface area of the electrolyzer; η ALK,F is the Faradaic efficiency of the ALK electrolyzer; f 11 、f 12 、f 21 and f 21 is a constant related to Faraday efficiency; η ALK is the operating efficiency of the ALK electrolyzer; is the per-unit value of the operating power of the ALK electrolyzer; M is the number of electrolyzer chambers; P ALK,e It is the rated power of a single ALK electrolyzer.

[0072] Table 1 Electrochemical model parameters of alkaline electrolyzer

[0073]

[0074]

[0075] This embodiment takes a 5MW ALK electrolyzer as an example. According to formula (1), formula (2), formula (3) and formula (4), we can get the following: Figure 4 The power-efficiency curve of the ALK electrolyzer is shown in Figure 2. When the power input to the ALK electrolyzer is low, the operating efficiency of the electrolyzer increases significantly with the increase of the input power. When the hydrogen production efficiency reaches the highest, the hydrogen production efficiency increases with This is because as the input power increases, the current density increases, resulting in an increase in overpotential, and more electrical energy is converted into thermal energy, resulting in a decrease in hydrogen production efficiency.

[0076] The hydrogen production power of the ALK electrolyzer increases first and then decreases with the increase of input power. The hydrogen production efficiency reaches its maximum at 25% of the rated power. Therefore, in this embodiment, the highest efficiency point power of the ALK electrolyzer is set to 25% of the rated power.

[0077] In this embodiment, the structure of the PEM electrolyzer is as follows Figure 5 As shown, the chemical reaction of the electrolysis process is Combined with the electrochemical model of the PEM electrolyzer shown in Table 2, the operating efficiency η of the PEM electrolyzer can be obtained PEM and input power per unit value The relationship equation is

[0078]

[0079] η PEM =η PEM,U η PEM,I (7)

[0080]

[0081] Among them, η PEM,U is the voltage efficiency of the PEM electrolyzer; U PEM,th is the thermal neutral voltage of the PEM electrolyzer; R is the gas constant; T PEM is the rated operating temperature of the PEM electrolyzer; α A is the anode charge transfer coefficient; z is the stoichiometric coefficient; F is the Faraday constant; i and i A are the electrolytic cell current density and the anode conversion current density, respectively; γ A is the anode activation area ratio; e A and e C are the thickness of the anode plate and cathode plate respectively; σ A and σ C are the electrical conductivity of the anode plate and cathode plate respectively; e M is the thickness of the proton exchange membrane; κ is the conductivity of the electrolyte; η PEM,I is the dynamic current efficiency of the PEM electrolyzer; D H is the diffusion coefficient of hydrogen; S H is the solubility coefficient of hydrogen; ΔP is the hydrogen partial pressure difference on both sides of the proton exchange membrane; η PEM is the operating efficiency of the PEM electrolyzer; U is the per-unit value of the operating power of the PEM electrolyzer; PEM,e and i e are the rated voltage and rated current density of the PEM electrolyzer respectively.

[0082] Table 2 PEM electrolyzer electrochemical model parameters

[0083]

[0084] Taking a 1MW PEM electrolyzer as an example, according to formula (5), formula (6), formula (7) and formula (8), we can get the following: Figure 6 The power-efficiency curve of the PEM electrolyzer is shown in When the hydrogen production efficiency is the highest, the hydrogen production efficiency is the highest. The overall trend and reasons for the power-efficiency curve for PEM electrolyzers are similar to those for alkaline electrolyzers. However, due to the higher current density and wider load range of PEM electrolyzers, their initial rise rate is faster and their operating range is wider.

[0085] Similarly, the hydrogen production efficiency of the PEM electrolyzer reaches its maximum at 10% of the rated power. Therefore, in this embodiment, the maximum efficiency point power of the PEM electrolyzer is set to 10% of the rated power.

[0086] Frequent start-stop operations of the electrolyzer will cause a certain degree of impact and wear on the electrolysis equipment, affecting the performance and reliability of the equipment. This will not only reduce the efficiency and quality of hydrogen production, but may also increase the maintenance cost and downtime of the equipment.

[0087] The electrolyzer needs to go through the steps of heating and pressurizing from the shutdown state to the normal working state. During the startup process, the electrolyzer does not work and does not produce hydrogen. The startup of the electrolyzer is divided into cold start and hot start. The temperature change of frequent cold start will reduce the life of the electrolyzer sealing material. Therefore, in reality, most electrolyzers are avoided from frequent cold starts. In addition, the time required for the actual electrolyzer to drop from the working state temperature to room temperature is too long, about ten hours, so this embodiment only considers the hot start state. Different types of electrolyzers require different times for hot start. ALK electrolyzers require several minutes, while PEM electrolyzers only require a few seconds. The time required for the shutdown process of the two electrolyzers is different from that of the startup. It only takes a few milliseconds to reduce the power to zero. Therefore, this embodiment ignores the shutdown process time of the two electrolyzers. This embodiment draws on the expression ideas of the start and stop of traditional thermal power units to derive the day-ahead scheduling start and stop constraints of the two electrolyzers as follows:

[0088] Assume T ALK,on is the minimum startup time of the ALK electrolyzer, the corresponding minimum startup time constraint can be expressed as:

[0089] 1) t>T ALK,on When , the conditions that ALK electrolyzer m must meet to start running at time t are: the continuous shutdown time before time t is greater than or equal to the minimum startup time, that is:

[0090]

[0091] in, It is a 0-1 variable indicating the start and stop status of ALK electrolyzer m at time t.

[0092] 2)1<t≤T ALK,on When ALK electrolyzer m is in shutdown state at the initial moment, the conditions that must be met for it to start running at time t are: the sum of the continuous shutdown time before time t and the initial shutdown time is greater than or equal to the minimum startup time, that is:

[0093]

[0094] in, The downtime of ALK electrolyzer m at the initial moment.

[0095] 3)1≤t≤T ALK,onWhen , if ALK electrolyzer m is in the power-on state at the initial moment, it is stipulated that ALK electrolyzer m cannot be powered on at time t, that is:

[0096]

[0097] 4) When t=1, if the ALK electrolyzer m is in the shutdown state at the initial moment, the conditions that must be met for it to start running at time t are: the continuous shutdown time before time t is greater than or equal to the minimum startup time, that is:

[0098]

[0099] Similarly, the minimum startup time constraint for PEM electrolyzer is:

[0100] 1) t>T PEM,on When the PEM electrolyzer n stops running at time t, the conditions that must be met are: the continuous shutdown time before time t is greater than or equal to the minimum startup time, that is:

[0101]

[0102] in, is a 0-1 variable indicating the start and stop status of the PEM electrolyzer n at time t; T PEM,on is the minimum startup time of the PEM electrolyzer.

[0103] 2)1<t≤T PEM,on When the PEM electrolyzer n is in shutdown state at the initial moment, the conditions that must be met for it to start running at time t are: the sum of the continuous shutdown time before time t and the initial shutdown time is greater than or equal to the minimum startup time, that is:

[0104]

[0105] in, The downtime of the PEM electrolyzer n at the initial moment.

[0106] 3)1≤t≤T PEM,on If PEM electrolyzer n is in the on state at the initial moment, it is stipulated that PEM electrolyzer n cannot be turned on at time t, that is:

[0107]

[0108] 4) When t=1, if the PEM electrolyzer n is in the shutdown state at the initial moment, the conditions that must be met for it to start running at time t are: the continuous shutdown time before time t is greater than or equal to the minimum startup time, that is:

[0109]

[0110] The startup costs of the two electrolyzers can be expressed as:

[0111]

[0112] Among them, C on is the startup cost of the two electrolyzers; c ALK,on and c PEM,on are the startup cost coefficients for ALK and PEM electrolyzers, respectively.

[0113] The downtime costs of the two electrolyzers are shown in formula (18):

[0114]

[0115] Among them, C off is the downtime cost of the two electrolyzers; c ALK,off and c PEM,off are the shutdown cost coefficients for ALK and PEM electrolyzers, respectively.

[0116] Taking into account the power-efficiency curves of the ALK electrolyzer and the PEM electrolyzer, the adjustment performance limitations and the second-level start-stop characteristics of the PEM electrolyzer, and in order to obtain the optimal hydrogen production effect, this embodiment is set to prioritize the power allocation of the ALK electrolyzer with lower operating costs, slower response speed, larger capacity configuration and poor adjustment performance, and utilize the rapid response characteristics of the PEM electrolyzer to absorb the remaining wind and solar power fluctuations, so as to reduce the frequent start-up and shutdown of the ALK and PEM electrolyzers and reduce the amount of wind and solar power curtailment, thereby increasing the flexibility of the hydrogen production system.

[0117] In order to ensure the safety of the electrolytic hydrogen production system and the high efficiency of hydrogen production, this embodiment proposes a refined interval power dynamic adjustment mechanism, which operates the ALK electrolyzer at the minimum starting power point P ALK,min , Maximum efficiency power point P ALK,h and rated power point P ALK,e As the segmentation point, the hydrogen production power is divided into 4 intervals; similarly, the PEM electrolyzer is started at the minimum power point P PEM,min , Maximum efficiency power point P PEM,h , rated power point P PEM,e and overload power point 1.2P PEM,e The hydrogen production power is divided into five intervals, with the power consumption of the ALK and PEM electrolyzers as the segmentation points. Based on the characteristics of each interval, a targeted hydrogen production power allocation strategy is developed to improve efficiency and drive the system toward optimal operation. To expand scheduling capacity, further enhance the absorption capacity of new energy, and reduce wind and solar power curtailment, this embodiment reserves one ALK electrolyzer and one PEM electrolyzer as slack capacity to cope with fluctuations in wind and solar power.

[0118] To extend the life of the electrolyzers while ensuring their safe and stable operation, this embodiment employs a two-tiered rotational operation of the electrolyzer array to ensure consistency between cells in each group. Taking into account the start-stop characteristics of the proposed ALK-PEM electrolyzers, the upper layer adopts the principle of first start, first shutdown, and last start, last shutdown, to ensure that the operating hours of each electrolyzer are as balanced as possible. The lower layer, based on the proposed refined dynamic power adjustment mechanism, divides the hydrogen production operating conditions of the electrolyzer cells into five categories: shutdown, high-efficiency, rated, overload, and fluctuating. Electrolyzers in operating conditions are rotated in the array to extend the service life of the entire system.

[0119] This embodiment proposes Figure 7 The power allocation strategy for the most efficient operation mode of the ALK-PEM electrolyzer combined hydrogen production system is shown in the figure, where P Wind,PV Contribute to the wind and light, P emax is the overload capacity of the electrolytic cell system, P ALK and P PEM are the capacities of ALK and PEM electrolyzers, respectively, and P ALK,h P is the power of a single ALK electrolyzer operating at the highest efficiency point. PEM,h is the power of a single PEM electrolyzer operating at the highest efficiency point, N ALK and N PEM are the number of ALK and PEM electrolyzer arrays respectively.

[0120] Taking into account the power-efficiency characteristics of the ALK electrolyzer and the PEM electrolyzer and the wide load characteristics of the PEM electrolyzer, this embodiment sets the overload capacity of the ALK-PEM electrolyzer system to P emax =P ALK +1.2P PEM , the system rated capacity is P e =P ALK +P PEM , the system's highest efficiency point capacity is P h =P ALK,h N ALK +P PEM,h N PEM The specific allocation strategy is as follows:

[0121] 1) When the wind and solar power output is greater than or equal to the electrolyzer system overload capacity (P Wind,PV ≥P emax ), set the ALK electrolyzer to rated power P ALK Operation, PEM electrolyzer with overload power 1.2P PEM run;

[0122] 2) When the wind and solar output is between the rated capacity and overload capacity of the electrolyzer system (P e ≤P Wind,PV <Pemax ), the power distribution to ALK electrolyzer is prioritized, with rated power P ALK Running, residual power P Wind,PV -P ALK The PEM electrolyzer is used for consumption;

[0123] 3) When the wind and solar power output is between the maximum efficiency point capacity and the rated capacity of the electrolyzer system (P h ≤P Wind,PV <P e ), the ALK electrolyzer and the PEM electrolyzer distribute input power according to the capacity ratio, that is, the ALK electrolyzer distributes power PEM electrolyzer power distribution

[0124]

[0125] 4) When the wind and solar power output is less than the maximum efficiency point capacity of the electrolyzer system When the ALK electrolyzer and the PEM electrolyzer distribute input power according to the capacity ratio of the highest efficiency point, that is, the ALK electrolyzer distributes power PEM electrolyzer power distribution

[0126]

[0127] N ALK The total power allocated to the ALK electrolyzer array in period t is The average power distribution of the electrolytic cell is The minimum starting power of a single ALK electrolyzer is P ALK,min , then the operation optimization strategy is formulated according to different operation intervals as follows:

[0128] 1) When , all ALK electrolyzers stop running, which is expressed as:

[0129]

[0130] in, and are the number of ALK electrolyzers operating at the highest efficiency point power and rated power in period t, respectively; is a 0-1 variable indicating the operating status of the ALK electrolyzer that bears the fluctuating power during period t; is the actual total hydrogen production power of the ALK electrolyzer during period t; is the fluctuating power borne by a single ALK electrolyzer during period t.

[0131] 2) and hour, Each ALK electrolyzer operates at the highest efficiency point power. The fluctuating power borne by each ALK electrolyzer is expressed as:

[0132]

[0133] 3) hour, Each ALK electrolyzer operates at the highest efficiency point power. The unit is running at rated power. The fluctuating power borne by the station is expressed as:

[0134]

[0135] 4) When , all ALK electrolyzers are operated at rated power, expressed as:

[0136]

[0137] The ALK electrolyzer array must also meet the following operational constraints:

[0138]

[0139] in, is the number of ALK electrolyzers that are out of service during period t.

[0140] Similarly, for PEM electrolyzer, let the number of electrolyzer arrays be N. PEM , where there is one electrolyzer that bears the fluctuating power, and the total power allocated to the PEM electrolyzer at time t is The average power distribution of the electrolytic cell is The minimum starting power of a single PEM electrolyzer is P PEM,min , then the operation optimization strategy of PEM electrolyzer can be expressed as:

[0141] 1) When , all PEM electrolyzers stop running, which is expressed as:

[0142]

[0143] in, and are the number of PEM electrolyzers operating at the highest efficiency point power, rated power, and overload power during period t, respectively; is a 0-1 variable indicating the operating status of the PEM electrolyzer that bears fluctuating power during period t; It refers to the actual total hydrogen production power of the PEM electrolyzer during period t; is the fluctuating power borne by a single PEM electrolyzer during period t.

[0144] 2) and hour, The PEM electrolyzer is operated at the highest efficiency point power. The fluctuating power borne by each PEM electrolyzer is expressed as:

[0145]

[0146] 3) hour, The PEM electrolyzer is operated at the highest efficiency point power. The unit is running at rated power. The fluctuating power borne by each PEM electrolyzer is expressed as:

[0147]

[0148] Among them, P PEM,e It is the rated power of a single PEM electrolyzer.

[0149] 4) hour, The PEM electrolyzer is operated at rated power. The station is running at overload power. The fluctuating power borne by the station is expressed as:

[0150]

[0151] 5) When , all PEM electrolyzers are operated at overload power, which is expressed as:

[0152]

[0153] The PEM electrolyzer array must also meet the following operational constraints:

[0154]

[0155] in, is the number of PEM electrolyzers that are out of service during period t.

[0156] Taking into account the refined interval power regulation mechanism that accounts for electrolyzer characteristics and the proposed ALK-PEM electrolyzer start-stop characteristics, each of the two electrolyzer units includes one electrolyzer in each interval to absorb fluctuating wind and solar power. To balance the operating time of each electrolyzer during the total operating cycle, including shutdown, peak efficiency point operation, rated power operation, overload power operation, and fluctuating power operation, this embodiment adopts a hybrid electrolyzer array with a two-tier rotation operation mode. This extends the overall service life of the electrolyzer system without increasing start-up and shutdown costs.

[0157] The upper array of hybrid electrolyzers adopts the principle of first start first shut down and last start last shut down to keep the working time of each electrolyzer as balanced as possible. Taking the ALK electrolyzer as an example, at t=0, the N ALK The electrolytic cells are sorted and the corresponding numbers are defined as queue Ω ALK ={1,2,3,···,N ALK -1,N ALK Without loss of generality, assume that the hydrogen production system determines that k ALK electrolyzers should be in a non-shutdown state (k<N ALK ), whose numbers form a first-in-first-out queue Right now The rest N ALK -k ALK electrolyzers are in shutdown state, and their numbers form another first-in-first-out queue Right now Assuming Δt is the electrolytic cell adjustment time step, the electrolytic cell array rotation process under different conditions is expressed as follows:

[0158] 1) If the wind and solar power output increases during the period t+Δt, the hydrogen production system decides that k+r ALK electrolyzers should be started during the period t+Δt, then Dequeue the first r elements and add them to the queue Tail, which means starting the queue first The first r electrolytic cells in . It is expressed as:

[0159]

[0160] in, for A queue consisting of the first r elements of .

[0161] 2) If the wind and solar power output decreases during the period t+Δt, the hydrogen production system decides that kr ALK electrolyzers should be started during the period t+Δt, then Dequeue the first r elements and add them to the queue Tail, that is, closing the queue first The first r electrolytic cells in . It is expressed as:

[0162]

[0163] in, for A queue consisting of the first r elements of .

[0164] The upper array of ALK electrolyzer rotates on and off in operation mode as follows Figure 8 and Figure 9 As shown (assuming that there are 10 ALK electrolyzers and 3 newly started and shut down units).

[0165] The rotation operation mode of the electrolyzer array under different conditions of the PEM electrolyzer is similar to that of the ALK electrolyzer and will not be described in detail.

[0166] On this basis, considering that a single electrolytic cell cannot be overloaded or bear fluctuating power for too long, the lower layer adopts a conventional electrolytic cell array rotation operation mode, and the electrolytic cells in operation are rotated in order of number. The ALK electrolytic cell rotation period is set to τ ALK , the PEM electrolyzer rotation period is τ PEM Taking the PEM electrolyzer as an example, the specific lower array rotation operation mode is as follows: Figure 10 As shown; each stage has three operating conditions, each operating condition is τ PEM The rotation operation is performed for the rotation period. Every time τ PEM , the PEM electrolyzers will assume the operating power of the previous PEM electrolyzer in order of numbering, and the fluctuating power will also be transferred from the current PEM electrolyzer to the next numbered PEM electrolyzer. When the wind and solar power output fluctuates significantly, the three operating conditions will change. The PEM electrolyzer that bears the fluctuating power will be transferred from the current PEM electrolyzer to the next numbered PEM electrolyzer without renumbering. This array rotation strategy ensures that each electrolyzer is evenly distributed in the time it withstands fluctuating conditions, ensuring that the operating time of each electrolyzer unit under different operating conditions is roughly the same, avoiding overuse of some electrolyzers and helping to improve the service life of the entire system.

[0167] This embodiment takes maximizing the net profit of hydrogen production by the hybrid electrolyzer hydrogen production system as the evaluation objective, and the decision variables are the number of ALK-PEM electrolyzers operating at each power point.

[0168] The objective function is:

[0169]

[0170] in, The income from selling hydrogen for the hybrid electrolyzer hydrogen production system; C op is the operating cost of the two electrolytic cells; C curt Penalty costs for curtailing wind and solar power.

[0171]

[0172] in, The unit price of hydrogen is 35 yuan / kg in this embodiment; is the hydrogen production of the ALK electrolyzer during period t; is the hydrogen production of the PEM electrolyzer during period t.

[0173]

[0174] in, The energy consumed per unit of hydrogen production is 50kW·h·kg in this embodiment. -1 ;η ALK,h and η ALK,e are the hydrogen production efficiency of the ALK electrolyzer when operating at the highest efficiency point power and rated power, η ALK,f The hydrogen production efficiency corresponding to the fluctuating power borne by the ALK electrolyzer.

[0175]

[0176] Among them, η PEM,h ,η PEM,e and η PEM,emax are the hydrogen production efficiencies of the PEM electrolyzer when operating at the highest efficiency point power, rated power, and overload power, respectively; PEM,f The hydrogen production efficiency corresponding to the fluctuating power borne by the PEM electrolyzer.

[0177] C op =C ALK,op +C PEM,op (42)

[0178]

[0179] Among them, C ALK,op and C PEM,op are the operating costs of ALK and PEM electrolyzers respectively; c ALK,op and c PEM,op are the operating cost coefficients of ALK and PEM electrolyzers, respectively.

[0180]

[0181] Among them, c curt is the unit penalty cost for curtailing wind and solar power, which is 0.6 yuan / (kW·h) in this embodiment; is the abandoned wind and solar power of the hydrogen production system during period t.

[0182] Constraints

[0183] 1) Power balance constraints

[0184]

[0185] 2) ALK-PEM electrolyzer output constraints

[0186]

[0187] 3) ALK electrolyzer power fluctuation constraints

[0188]

[0189] 4) PEM electrolyzer power fluctuation constraints

[0190]

[0191] 5) Minimum start-stop time constraints for ALK-PEM electrolyzers

[0192] See formula (9) to formula (16) for details.

[0193] 6) ALK-PEM electrolyzer array operation constraints

[0194] See formula (23) and formula (29) for details.

[0195] 7) ALK-PEM electrolyzer upper array rotation start and stop constraints

[0196] See formula (30)-formula (37) for details.

[0197] The mathematical model proposed in this embodiment is a mixed-integer linear program (MILP) problem, which can be directly solved using the commercial solver Gurobi.

[0198] Case Analysis

[0199] In order to verify the effectiveness of the optimal power allocation strategy for ALK-PEM combined hydrogen production proposed in this embodiment, this embodiment takes the demonstration project data of a certain region as an example, and configures a wind turbine capacity of 120MW and a photovoltaic unit capacity of 60MW. The relevant parameters of equipment such as ALK electrolyzers and PEM electrolyzers are specifically shown in Table 3. Considering the optimal configuration of the ALK-PEM hybrid electrolyzer and the startup and regulation characteristics of the ALK and PEM electrolyzers, the capacity ratio of ALK to PEM is selected as 2.5:1, that is, the number of ALK electrolyzer arrays is configured as N ALK (N ALK =10) units, the number of PEM electrolyzer arrays is N PEM (N PEM =20). Considering the varying timescales of the ALK-PEM electrolyzer power response, this embodiment uses a 2-hour scheduling cycle and a sampling timescale of seconds. The model was solved using MATLAB 2023b software using the Gurobi solver. The computer was running Windows 11, with an Intel Core i7-14650H CPU running at 2.2 GHz and 16 GB of memory.

[0200] Table 3 Comparison of different electrolytic cell parameters

[0201]

[0202]

[0203] This embodiment performs a second-level prediction of wind and solar power generation output on six typical days randomly selected from the 8:00-10:00 period throughout the year. The wind and solar power generation output prediction results are as follows: Figure 11 shown.

[0204] To verify the effectiveness of the optimal power allocation strategy for the ALK-PEM combined hydrogen production system proposed in this example, it was compared and analyzed with the traditional power allocation strategy. The comparison results of hydrogen production on six typical days are shown in Table 4.

[0205] Table 4 Operation status under different power allocation schemes on typical days

[0206]

[0207] As shown in Table 4, over a typical six-day scheduling cycle, the total hydrogen production under the traditional power allocation strategy is 8336.02 kg. The optimal power allocation strategy for the ALK-PEM hydrogen production system, which takes into account electrolyzer start-up and shutdown, proposed in this embodiment, can produce 8820.01 kg, increasing total hydrogen production by 5.806%. Regarding wind and solar curtailment, the average curtailment rate is 7.08% under the traditional scheme, while the average curtailment rate under the power allocation strategy proposed in this embodiment is 0.785%, a reduction of 88.91%, significantly improving the system's ability to absorb wind and solar power. In terms of hydrogen production revenue, the traditional scheme produces 1.4965826 million yuan, while the scheme proposed in this embodiment achieves a total hydrogen production revenue of 2.0070732 million yuan, an increase of 34.110%. In summary, compared with the equal power distribution strategy in the traditional scheme, the optimal power allocation strategy of the ALK-PEM combined hydrogen production system in this embodiment can reasonably distribute the fluctuating power of wind and solar power according to the working conditions of each electrolyzer array, maximize the hydrogen production efficiency of the electrolyzer array, and effectively improve the wind and solar power absorption capacity while increasing the hydrogen production income.

[0208] To further verify the economic advantages of the optimal power allocation strategy for the ALK-PEM combined hydrogen production system proposed in this embodiment, which takes into account the second-level start-stop characteristics of the electrolyzer, a comparative analysis is conducted with the power allocation strategy in the traditional scheme. Various hydrogen production costs on typical day 2 and typical day 4 are selected for comparison. The results are shown in Table 5.

[0209] Table 5 Hydrogen production costs under different power allocation schemes

[0210]

[0211] As can be seen from Table 5, compared with the traditional solution, the penalty costs for wind and solar power curtailment in the solution proposed in this embodiment are reduced by 89.57% and 94.63%, respectively, the total operating costs of the electrolyzer are reduced by 5.46% and 17.94%, respectively, and the start-up and shutdown costs in four typical days are reduced by 21.21%. This is because the proposed power allocation strategy comprehensively considers the operating characteristics of ALK and PEM electrolyzers, allocates power according to the optimal efficiency operation mode of ALK and PEM electrolyzers, and can give full play to the complementary advantages of ALK-PEM electrolyzers, reduce the start-up and shutdown operations of the electrolyzers, and help to improve the service life of the electrolyzers. Compared with the traditional solution, although the operating cost of the ALK electrolyzer of the proposed solution is higher than that of the traditional solution, the corresponding operating cost of the PEM electrolyzer is greatly reduced. This is because the unit operating cost of the PEM electrolyzer is high. The solution proposed in this embodiment reasonably allocates the wind and solar power output to avoid the excessive use of one electrolyzer. It not only effectively reduces the operating cost of the electrolyzer, but also increases the dispatchable space of the electrolyzer, verifying the effectiveness of the proposed solution in terms of flexibility and economy.

[0212] In order to further verify the advantages of the power allocation strategy proposed in this embodiment in accommodating the fluctuating power of wind and solar power by considering the second-level start-stop characteristics of the electrolyzer, it is compared and analyzed with the power allocation strategy in the traditional scheme. The wind and solar power output and the electrolysis hydrogen production power on typical days 2 and 4 are compared as shown in the following results. Figure 12 shown.

[0213] Depend on Figure 12 (a) and Figure 12 (b) By comparison, it can be seen that in the sampling time period 1 to 200 in typical day 2, the hydrogen production power of both schemes cannot effectively follow the fluctuation of wind and solar power, resulting in the abandonment of wind and solar power. This is because the wind and solar input power in this time period exceeds the maximum output power of ALK and PEM electrolyzers, and at this time, ALK and PEM electrolyzers are operating at maximum power; in the sampling time period 241 to 1440, compared with the traditional scheme, the hydrogen production power of ALK and PEM electrolyzers under the power allocation strategy proposed in this embodiment can effectively follow the fluctuation of wind and solar power, and there is no abandonment of wind and solar power. This is because compared with the capacity-sharing power allocation strategy proposed in the traditional scheme, the scheme proposed in this embodiment allocates input power according to the optimal efficiency operation mode of ALK and PEM electrolyzers, so that the PEM electrolyzer retains a part of the hydrogen production capacity and has greater flexibility, thereby greatly improving the hydrogen production system's ability to absorb new energy. Figure 12 (c) and Figure 12(d) By comparison, it can be seen that between the sampling time periods 181 and 420 on typical day 4, compared with the scheme proposed in the traditional scheme, the hydrogen production power of the ALK and PEM electrolyzers under the power allocation strategy proposed in this embodiment can effectively follow the low-power wind and solar power fluctuations, and there is no wind and solar power abandonment. This is because the proposed scheme takes into account the situation where the average power in the lower-level power allocation strategy is less than the minimum value of the electrolyzer hydrogen production power, and formulates a targeted power allocation strategy according to the different situations of the hydrogen production power partitioning, so that the hydrogen production system can better adapt to the different output levels of new energy.

[0214] In order to verify the hydrogen production power fast tracking capability of the proposed method and the second-level response characteristics of the PEM electrolyzer, the sampling time periods 481-800 on typical day 1 and typical day 6 were selected to compare the hydrogen production power on the second-level time scale with the conventional 5-minute time scale. The results are as follows: Figure 13 shown.

[0215] Depend on Figure 13 (a) It can be seen that in the sampling period 481-780 on a typical day 1, when the wind and solar power output shows a weakening trend over time, compared with the conventional 5-minute time scale, the electrolyzer second-level time scale scheme proposed in this embodiment can configure the power required by each electrolyzer according to the wind and solar power in real time, and can quickly respond to wind and solar power fluctuations, avoiding the unrealistic phenomenon that the hydrogen production power is higher than the wind and solar power output under the conventional 5-minute time scale; Figure 13 (b) It can be seen that during the sampling period 541-780 on a typical day 1, when the wind and solar output showed an increasing trend over time, the electrolyzer's second-level time scale scheme proposed in this embodiment can quickly adjust the electrolyzer's hydrogen production power to follow the wind and solar output, compared to the conventional 5-minute time scale, avoiding the phenomenon that the hydrogen production power cannot quickly follow the wind and solar output under the conventional 5-minute time scale, resulting in power abandonment. The proposed second-level time scale scheme can fully utilize the wind and solar output and improve the level of new energy consumption. In summary, the power optimal allocation strategy for the ALK-PEM electrolyzer hydrogen production system proposed in this embodiment, which takes into account the second-level start-stop characteristics, can more fully utilize the second-level response characteristics of the PEM electrolyzer, achieve rapid tracking of wind and solar output fluctuations, reduce the occurrence of wind and solar abandonment, and significantly improve the ability to absorb new energy.

[0216] In order to verify the effectiveness of the ALK-PEM electrolyzer array in cooperating with each other to produce hydrogen under the power allocation strategy proposed in this embodiment, the wind and solar power output curves and the hydrogen production states of the ALK and PEM electrolyzers are shown in the following figure: Figure 14 shown.

[0217] Depend on Figure 14(a) It can be seen that under the second-level power allocation strategy proposed in this embodiment, the power of hydrogen production by electrolysis can quickly follow the output of wind and solar power, reducing energy waste; Figure 14 (b)~ Figure 14 (e) It can be seen that in a single time period, there are multiple electrolyzers operating under different hydrogen production conditions, including operation at the highest efficiency point, rated operation, overload operation, and operation with fluctuating power. The second-level optimal power allocation strategy proposed in this embodiment is used to comprehensively consider key factors such as the power-efficiency curve, regulation performance, and capacity size of the ALK electrolyzer and the PEM electrolyzer, and formulate a corresponding power allocation plan to give priority to the power allocation of ALK electrolyzers with lower operating costs, slower response speeds, larger capacity configurations, and poorer regulation performance. At the same time, it is ensured that as many electrolyzers as possible are operated simultaneously to give full play to their efficiency characteristics and reduce start-stop operations. Because of its second-level response characteristics, the PEM electrolyzer can cooperate with the ALK electrolyzer to absorb the remaining fluctuating wind and solar power output. By rationally allocating wind and solar power input power, the occurrence of wind and solar power curtailment can be reduced, achieving rational power utilization. In addition, under the optimal power allocation strategy of the ALK-PEM combined hydrogen production system proposed in this embodiment, which takes into account the second-level start and stop characteristics of the electrolyzer, the system does not experience frequent start and stop operations. It mainly responds to rapidly changing renewable energy output by adjusting the power of the operating electrolyzer. The proposed power allocation strategy not only maximizes the absorption of renewable energy power, but also avoids frequent start and stop of hydrogen production equipment, verifying the effectiveness of the proposed optimal power allocation strategy.

[0218] In order to verify the effectiveness of the ALK-PEM electrolyzer double-layer array rotation operation mode under the power allocation strategy proposed in this embodiment, the first six ALK electrolyzers in the 1st to 10th sampling period of a typical day are taken as an example (the remaining four electrolyzers have been in the hydrogen production operation state in the 1st to 10th sampling period, which is similar to the operation state of ALK electrolyzer 6 and will not be repeated here). The upper array rotation operation state diagram is as follows: Figure 15 shown.

[0219] Depend on Figure 15It can be seen that at the initial moment of sampling, ALK electrolyzer 1 is in a shutdown state, and the other five electrolyzers are in a hydrogen production operation state; when the hydrogen production system decides that a total of two ALK electrolyzers need to be shut down in sampling period 2, ALK electrolyzer 2 is shut down on the basis that ALK electrolyzer 1 has been shut down, that is, ALK electrolyzer 2, which is running first, is shut down first, and the remaining electrolyzers remain in operation; similarly, electrolyzers 3 and 4 are shut down in sampling period 4, and electrolyzer 5 is shut down in sampling period 5. When the hydrogen production system decides that a total of 9 ALK electrolyzers need to be started during sampling period 7, then based on the fact that ALK electrolyzers 6 to 10 have been started during sampling period 7, a start-up signal needs to be applied to the ALK electrolyzers 1 to 4 that were shut down first during sampling period 6 to put them into a hot start state, and after the minimum start-up time of the ALK electrolyzer is 5 minutes (sampling period 7), they enter the hydrogen production operation stage; similarly, a start-up signal is applied to electrolyzer 5 during sampling period 7 to put it into the hydrogen production operation stage during sampling period 8, satisfying the start-stop strategy of shutting down first and starting up later, and shutting down later and starting up later. In summary, the upper array rotation operation mode adopted in this embodiment can balance the working time of each electrolyzer as much as possible, extend the service life of the electrolyzer array without increasing the start-up and shutdown costs, and verify the feasibility of the electrolyzer upper array rotation operation mode under the proposed power allocation strategy.

[0220] In order to further verify the effectiveness of the rotation operation mode of the lower array of hybrid electrolyzers, the first six PEM electrolyzers in the 306-385 sampling period of a typical day were selected, and the rotation operation status of the lower array is shown in the figure below. Figure 16 shown.

[0221] Depend on Figure 16 It can be seen that during the sampling period, 14 PEM electrolyzers are in rated power operation, 5 PEM electrolyzers are in the highest efficiency point operation, and the remaining 1 PEM electrolyzer is in a fluctuating operation state. At the same time, the rotation period τ of the PEM electrolyzer is set PEM =10s, that is, every 10s, the operating status of the PEM electrolyzer will rotate once in a sequential array form. For example, at sampling time 306, PEM electrolyzer 1 bears the fluctuating power, while at sampling time 307, the fluctuating power is borne by PEM electrolyzer 2, and so on. In summary, the lower-layer array rotation operation mode adopted in this embodiment can achieve the most balanced time share of each electrolyzer unit under different operating conditions, avoid excessive use of some electrolyzers, ensure the safe and stable operation of each electrolyzer, reduce the safety risks during the operation of the electrolyzer, improve the safety and reliability of hydrogen production, and help to improve the overall service life of the ALK-PEM electrolyzer combined hydrogen production system.

[0222] Using green electricity for electrolysis to produce hydrogen is one of the primary methods for absorbing new energy and promoting clean energy. To enhance the compatibility of hydrogen production systems with fluctuating electrolysis power sources and increase hydrogen production revenue, this example proposes a combined ALK-PEM electrolyzer electrolysis method for hydrogen production. Taking into account the second-level response characteristics of the PEM electrolyzer and the large single-cell capacity and economical efficiency of the ALK electrolyzer, this study investigates the optimal power allocation for hydrogen production systems in typical scenarios. Through case analysis, the following conclusions are drawn:

[0223] 1) The proposed second-level start-stop method, by further shortening the time scale, fully utilizes the second-level response characteristics of the PEM electrolyzer, fully utilizes the output of wind and solar power, reduces the occurrence of wind and solar power curtailment, and effectively improves the level of new energy consumption;

[0224] 2) The proposed optimal power allocation strategy for the ALK-PEM electrolyzer combined hydrogen production system can improve the adaptability of the hydrogen production system to the fluctuating power of wind and solar power input. Compared with the equal-sharing strategy, the proposed highest-efficiency operation mode allocation strategy increased the total hydrogen production by 5.806%, reduced the system's wind and solar power curtailment rate by 88.91%, and increased the system's hydrogen production revenue by 34.110%. This significantly improved the economy and flexibility of the ALK-PEM electrolyzer combined hydrogen production system and achieved the rational utilization of the hybrid electrolyzer capacity.

[0225] 3) The proposed optimal power allocation strategy allocates power according to the highest efficiency operation mode of the ALK-PEM electrolyzer, fully tapping the hydrogen production potential of the two electrolyzers and achieving complementary advantages. While maximizing hydrogen production benefits, it avoids frequent starts and stops and improves the level of new energy consumption.

[0226] 4) To balance the operating time of each electrolyzer under different operating conditions, this embodiment constructs a hybrid electrolyzer double-layer array rotation operation model. The results show that the use of a double-layer array rotation operation strategy can effectively avoid excessive use of some electrolyzers. Without increasing the start-up and shutdown costs of the electrolyzers, it ensures the state consistency of each electrolyzer and the operational safety of the hydrogen production system, which is conducive to improving the overall service life of the hydrogen production system.

[0227] This example addresses the problems of existing electrolyzer models, which mostly characterize their operating characteristics on a time scale of hours or minutes, failing to fully exploit their second-level start-stop characteristics, resulting in low operating efficiency and insufficient new energy absorption capacity. This example proposes an optimal power allocation strategy for a combined hydrogen production system using ALK electrolyte and PEM electrolyzers, taking into account the second-level start-stop characteristics of the electrolyzers. The example analyzes the operating mechanisms of ALK and PEM electrolyzers and deduces their power-efficiency curves. An optimal power allocation strategy for the ALK-PEM combined electrolysis hydrogen production system is developed based on the peak efficiency, rated power, and overload power points on the curves, taking into account the operating costs, cell capacities, and regulation performance of the two electrolyzers, as well as the second-level start-stop and response characteristics of the PEM electrolyzer. Furthermore, the optimal power allocation strategy for the ALK-PEM combined electrolysis hydrogen production system is implemented by combining the rotation operation rules of a multi-electrolyzer double-layer array to achieve reasonable array power allocation between groups in the hybrid electrolyzer hydrogen production system. Finally, using actual data from a demonstration project in a certain region, the proposed optimal power allocation strategy for ALK-PEM electrolyzers is demonstrated to promote new energy absorption while increasing hydrogen production revenue.

[0228] Example 2

[0229] The second embodiment of the present invention introduces a power distribution system for an ALK-PEM electrolyzer hydrogen production system.

[0230] like Figure 17 The power distribution system of an ALK-PEM electrolyzer hydrogen production system shown includes:

[0231] an acquisition module configured to acquire operating characteristics of the ALK electrolyzer and the PEM electrolyzer and construct an ALK-PEM electrolyzer combined hydrogen production system;

[0232] A determination module configured to determine the operation mode of the electrolyzers of the hydrogen production system based on the start-stop characteristics of the electrolyzers of the constructed ALK-PEM electrolyzer combined hydrogen production system, taking into account the second-level start-stop characteristics of the PEM electrolyzers, and adopting a double-layer rotation operation mode of the electrolyzer array;

[0233] A construction module is configured to construct an optimal power allocation model taking into account the start and stop of the electrolyzer according to the determined electrolyzer operation mode and with the goal of maximizing the net profit of the hybrid electrolyzer hydrogen production system;

[0234] The solution module is configured to solve the constructed optimal power allocation model to complete the power allocation of the ALK-PEM electrolyzer hydrogen production system.

[0235] The detailed steps are the same as those of the power distribution method for an ALK-PEM electrolyzer hydrogen production system provided in Example 1, and will not be repeated here.

[0236] Example 3

[0237] A third embodiment of the present invention provides a computer-readable storage medium.

[0238] A computer-readable storage medium stores a program thereon, which, when executed by a processor, implements the steps of a power distribution method for an ALK-PEM electrolyzer hydrogen production system as described in the first embodiment of the present invention.

[0239] The detailed steps are the same as those of the power distribution method for an ALK-PEM electrolyzer hydrogen production system provided in Example 1, and will not be repeated here.

[0240] Example 4

[0241] A fourth embodiment of the present invention provides an electronic device.

[0242] An electronic device includes a memory, a processor, and a program stored in the memory and running on the processor. When the processor executes the program, it implements the steps of the power distribution method of an ALK-PEM electrolyzer hydrogen production system as described in Example 1 of the present invention.

[0243] The detailed steps are the same as those of the power distribution method for an ALK-PEM electrolyzer hydrogen production system provided in Example 1, and will not be repeated here.

[0244] Example 5

[0245] A fifth embodiment of the present invention provides a computer program product.

[0246] A computer program product includes software code, wherein the program in the software code executes the steps in the power distribution method of an ALK-PEM electrolyzer hydrogen production system as described in the first embodiment of the present invention.

[0247] The detailed steps are the same as those of the power distribution method for an ALK-PEM electrolyzer hydrogen production system provided in Example 1, and will not be repeated here.

[0248] It will be understood by those skilled in the art that the embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of the present invention may be implemented in various computer languages, for example, the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0249] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0250] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0251] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0252] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0253] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

[0254] The above description is merely a preferred embodiment of this embodiment and is not intended to limit this embodiment. Those skilled in the art will readily appreciate that this embodiment may be modified and varied in various ways. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this embodiment shall be within the scope of protection of this embodiment.

Claims

1. A power distribution method for an ALK-PEM electrolyzer hydrogen production system, characterized in that: include: Obtain the operating characteristics of ALK electrolyzers and PEM electrolyzers and build an ALK-PEM electrolyzer combined hydrogen production system; The acquired operating characteristics of the ALK electrolyzer and PEM electrolyzer include at least the power-efficiency curve, electrolyzer cell capacity, electrolyzer regulation performance, operating cost, start-stop characteristics, and second-level response characteristics; Based on the start-stop characteristics of the electrolyzers in the constructed ALK-PEM electrolyzer combined hydrogen production system, and considering the second-level start-stop characteristics of the PEM electrolyzer, the operation mode of the electrolyzers in the hydrogen production system is determined by adopting a double-layer rotation operation mode of the electrolyzer array. The electrolyzer array adopts a double-layer rotation operation mode. The upper layer adopts the principle of first start-up first shutdown and last start-up last shutdown to balance the working hours of different electrolyzers. The lower layer rotates the array according to the operating conditions of the electrolyzer single hydrogen production. The operating conditions of the electrolyzer unit producing hydrogen include at least a shutdown operating state, a high-efficiency operating state, a rated operating state, an overload operating state, and a fluctuating operating state; Based on the determined electrolyzer operation mode, with the goal of maximizing the net profit of the hybrid electrolyzer hydrogen production system, an optimal power allocation model taking into account the start and stop of the electrolyzer is constructed; The objective function of the constructed optimal power allocation model taking into account the start and stop of the electrolyzer is ;in, The net income of the hybrid electrolyzer hydrogen production system; Revenue from hydrogen sales for the hybrid electrolyzer hydrogen production system; The operating costs of ALK electrolyzers and PEM electrolyzers; The operating cost of the hybrid electrolyzer hydrogen production system; Downtime costs for hybrid electrolyzer hydrogen production systems; Penalty costs for wind and solar curtailment in hybrid electrolyzer hydrogen production systems; The constraints of the constructed optimal power allocation model taking into account the start and stop of the electrolyzer include at least power balance constraints, ALK-PEM electrolyzer output constraints, ALK electrolyzer fluctuating power constraints, PEM electrolyzer fluctuating power constraints, ALK-PEM electrolyzer minimum start and stop time constraints, ALK-PEM electrolyzer array operation constraints, and ALK-PEM electrolyzer upper array rotation start and stop constraints; Solve the constructed optimal power allocation model and complete the power allocation of the ALK-PEM electrolyzer hydrogen production system.

2. A power distribution system for an ALK-PEM electrolyzer hydrogen production system, characterized in that: include: an acquisition module configured to acquire operating characteristics of the ALK electrolyzer and the PEM electrolyzer and construct an ALK-PEM electrolyzer combined hydrogen production system; The acquired operating characteristics of the ALK electrolyzer and PEM electrolyzer include at least the power-efficiency curve, electrolyzer cell capacity, electrolyzer regulation performance, operating cost, start-stop characteristics, and second-level response characteristics; A determination module configured to determine the operation mode of the electrolyzers of the hydrogen production system based on the start-stop characteristics of the electrolyzers of the constructed ALK-PEM electrolyzer combined hydrogen production system, taking into account the second-level start-stop characteristics of the PEM electrolyzers, and adopting a double-layer rotation operation mode of the electrolyzer array; The electrolyzer array adopts a double-layer rotation operation mode. The upper layer adopts the principle of first start-up first shutdown and last start-up last shutdown to balance the working hours of different electrolyzers. The lower layer rotates the array according to the operating conditions of the electrolyzer single hydrogen production. The operating conditions of the electrolyzer unit producing hydrogen include at least a shutdown operating state, a high-efficiency operating state, a rated operating state, an overload operating state, and a fluctuating operating state; A construction module is configured to construct an optimal power allocation model taking into account the start and stop of the electrolyzer according to the determined electrolyzer operation mode and with the goal of maximizing the net profit of the hybrid electrolyzer hydrogen production system; The objective function of the constructed optimal power allocation model taking into account the start and stop of the electrolyzer is ;in, The net income of the hybrid electrolyzer hydrogen production system; Revenue from hydrogen sales for the hybrid electrolyzer hydrogen production system; The operating costs of ALK electrolyzers and PEM electrolyzers; The operating cost of the hybrid electrolyzer hydrogen production system; Downtime costs for hybrid electrolyzer hydrogen production systems; Penalty costs for wind and solar curtailment in hybrid electrolyzer hydrogen production systems; The constraints of the constructed optimal power allocation model taking into account the start and stop of the electrolyzer include at least power balance constraints, ALK-PEM electrolyzer output constraints, ALK electrolyzer fluctuating power constraints, PEM electrolyzer fluctuating power constraints, ALK-PEM electrolyzer minimum start and stop time constraints, ALK-PEM electrolyzer array operation constraints, and ALK-PEM electrolyzer upper array rotation start and stop constraints; The solution module is configured to solve the constructed optimal power allocation model to complete the power allocation of the ALK-PEM electrolyzer hydrogen production system.

3. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the power distribution method of an ALK-PEM electrolyzer hydrogen production system as described in claim 1 are implemented.

4. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the program, the steps of the power distribution method of the ALK-PEM electrolyzer hydrogen production system as described in claim 1 are implemented.

5. A computer program product comprising software code, characterized in that The program in the software code executes the steps of the power distribution method for an ALK-PEM electrolyzer hydrogen production system as described in claim 1.

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