A dual-period green electricity hydrogen production system electrolytic cell cluster control method

Abstract

This invention discloses a dual-cycle control method for an electrolyzer cluster in a green electricity-to-hydrogen system. The green electricity-to-hydrogen system includes a power generation unit, a public power grid, auxiliary systems for the hydrogen production station, an electrolyzer cluster, a control unit, a hydrogen storage and utilization unit, a power generation prediction unit, a first power measurement unit, a second power measurement unit, and a third power measurement unit. The method includes load adjustment at intervals of electrolyzer cluster load regulation. The control system determines the load level of the electrolyzer cluster and sends the control to the rectifiers at the front end of the electrolyzers in the cluster for adjustment. It also includes updating the start-stop strategy of the electrolyzer cluster at intervals of update, prior to load regulation. This solution fully leverages the advantage of the hydrogen production system's ability to mitigate power fluctuations, enabling real-time tracking of hydrogen production load across a wide range of wind and solar power outputs, ensuring the stable operation of the entire hydrogen production process system, and avoiding frequent start-stop cycles of the electrolyzers.

Description

Technical Field

[0001] This invention belongs to the field of renewable energy hydrogen production technology, specifically relating to a dual-cycle green electricity hydrogen production system electrolyzer cluster control method. Background Technology

[0002] By generating electricity from renewable energy sources such as wind and solar power, and producing hydrogen through water electrolysis, energy can be stored, transported, and utilized in the form of hydrogen. Further utilizing hydrogen to replace traditional fuels based on fossil fuels such as coal and oil can achieve decarbonization in transportation, metallurgy, and chemical industries.

[0003] The key to coupling hydrogen production with renewable energy lies in utilizing the load regulation capabilities of the hydrogen production unit to address the volatility issues of wind and solar power generation. Specifically, this requires the load of the hydrogen production stage to follow the output changes of the power generation stage in real time, minimizing dependence on the main power grid. The ultimate goal is to achieve off-grid operation of the wind-solar-hydrogen system. Currently, there are several large-scale integrated wind power, solar power, and hydrogen production projects both domestically and internationally. However, to avoid the intermittent and volatile nature of renewable energy output, most still heavily rely on the regulation functions of the main power grid. Grid support allows hydrogen production equipment to operate at a constant load, reducing the difficulty of system control and achieving higher utilization rates, which helps reduce hydrogen product costs. However, this operating mode does not leverage the advantages of the hydrogen production unit as a variable load in mitigating power fluctuations. It fails to assist in the large-scale integration of wind and solar power into the energy system and instead puts new pressure on the grid's peak-shaving capacity, requiring more thermal power units to achieve balance. Simultaneously, the need to obtain large amounts of electricity from the grid results in high electricity costs.

[0004] The further development of large-scale renewable energy hydrogen production projects necessitates more proactive control strategies for hydrogen production systems, enabling real-time adjustment of hydrogen production load in tandem with power generation. Wind and solar power output varies widely, fluctuating between 0% and 100% of rated power depending on wind speed or solar irradiance, and these fluctuations are rapid, potentially increasing or decreasing significantly within minutes or even shorter periods. This presents challenges to the regulation of hydrogen production systems. While electrolyzers offer some regulation capabilities, they are also subject to limitations, especially considering that large-scale hydrogen production projects typically employ alkaline electrolyzers. Firstly, to ensure the stable operation of the entire hydrogen production process, the regulation speed of the electrolyzers needs to be limited. Secondly, for safety reasons, the operating load range of electrolyzers is generally maintained between 50% and 100%. To match the 0-100% fluctuations of wind and solar power, the method of shutting down some electrolyzers is generally used to expand the load fluctuation range; however, frequent start-ups and shutdowns reduce the electrolyzer lifespan. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a dual-cycle green electricity hydrogen production system electrolyzer cluster control method, which solves the problems of poor control strategies in existing technical solutions and the additional cost caused by relying on the power grid or the start-up and shutdown of the electrolyzer. This method enables the hydrogen production load to follow the wide load range of wind and solar power output in real time, while taking into account the lifespan of the electrolyzer and avoiding frequent start-up and shutdown.

[0006] According to the technical solution of the present invention, the present invention provides a dual-cycle green electricity hydrogen production system electrolyzer cluster control method, wherein the green electricity hydrogen production system adopted includes a power generation unit, a public power grid, a hydrogen production station auxiliary system, an electrolyzer cluster, a control unit, a hydrogen storage and use unit, and a power generation prediction unit.

[0007] The power generation unit is connected to the public power grid, the hydrogen production station auxiliary system, and the electrolyzer cluster; the hydrogen outlet of the electrolyzer cluster is connected to the hydrogen storage and usage unit; the power generation unit is connected to the first power measurement unit, the hydrogen production station auxiliary system is connected to the second power measurement unit, and the electrolyzer cluster is connected to the third power measurement unit; the control unit is connected to the first power measurement unit, the second power measurement unit, the third power measurement unit, the power generation prediction unit, and the electrolyzer cluster.

[0008] The power generation unit generates electricity to supply the auxiliary system of the hydrogen production station and the electrolyzer cluster. When the power generation of the power generation unit is not equal to the power consumption of the auxiliary system of the hydrogen production station and the electrolyzer cluster, the excess power is supplied to the public power grid, or the shortfall is made up by the public power grid. The first power measurement unit is used to measure the power generation of the power generation unit. The second power measurement unit is used to measure the power consumption of the auxiliary system of the hydrogen production station. The third power measurement unit is used to measure the power consumption of the electrolyzer cluster. The control unit is used to receive the power data measured by the first power measurement unit, the second power measurement unit, and the third power measurement unit, as well as the power generation prediction data from the power generation prediction unit, and formulate control strategies based on the data, and send control commands to the electrolyzer cluster.

[0009] The dual-cycle green electricity hydrogen production system electrolyzer cluster control method includes performing load adjustment every cycle T1 of the electrolyzer cluster load adjustment; when performing load adjustment, the control system determines the load level of the electrolyzer cluster and sends it to the rectifier at the front end of the electrolyzer in the electrolyzer cluster to perform the adjustment. The specific steps of load adjustment include the following:

[0010] Step S11: Subtract the average power generation measured by the first power measurement unit from the average power consumption of the hydrogen production station auxiliary system measured by the second power measurement unit to obtain the total available power P_src of the electrolyzer.

[0011] Step S12: Combine P_src and the hydrogen supply limit imposed by the hydrogen storage and usage unit to obtain the target power P_tot_aim of the electrolyzer cluster;

[0012] Step S13: Allocate the target power P_tot_aim of the electrolytic cell cluster to a single electrolytic cell. During allocation, first deduct the power required by the electrolytic cell in startup, and then allocate the remaining power to the electrolytic cell that is already in operation to obtain the adjustment target power P_indiv of each electrolytic cell, thus forming an electrolytic cell power adjustment strategy.

[0013] Step S14: The electrolytic cell power adjustment strategy is sent to the electrolytic cell cluster for execution: the prescribed startup process is executed for the electrolytic cells during startup, and the power of the electrolytic cells that are already in operation is adjusted to the corresponding P_indiv.

[0014] The dual-cycle green electricity hydrogen production system electrolyzer cluster control method further includes updating the electrolyzer cluster start-up and shutdown strategy every cycle T2. If the time for updating the electrolyzer cluster start-up and shutdown strategy overlaps with the time for load adjustment, the electrolyzer cluster start-up and shutdown strategy is updated first, and then the load adjustment is performed. The specific steps for updating the electrolyzer cluster start-up and shutdown strategy are as follows:

[0015] Step S21: Subtract the average power generation measured by the first power measurement unit from the average power consumption of the hydrogen production station auxiliary system measured by the second power measurement unit to obtain the first average available green power P_avg1.

[0016] Step S22: Read and calculate the average available green power from the past 2*T2 to the past T2 time period to obtain the zeroth average available green power P_avg0, and then obtain the second average available green power P_avg2=2*P_avg1-P_avg0;

[0017] Step S23: Read the predicted power generation data P_avg3 for the next time period T2;

[0018] Step S24, calculate the weighted average power P_avg=a*P_avg1+b*P_avg2+(1-ab)*P_avg3, where a is the first weighting coefficient and b is the second weighting coefficient;

[0019] Step S25: Calculate the optimal number of electrolytic cells to operate, n_on, and formulate an electrolytic cell start-up and shutdown strategy;

[0020] Step S26: Send the electrolytic cell start-up and shutdown strategy to the electrolytic cell cluster for execution.

[0021] Furthermore, in step S12, the specific method for calculating the target power P_tot_aim of the electrolytic cell cluster is as follows:

[0022] If there is no limit to the hydrogen supply, then P_tot_aim = P_src;

[0023] If there are limitations on the hydrogen supply, the acceptable hydrogen flow rate limits for the hydrogen storage and usage unit are converted into the upper and lower power limits of the electrolyzer cluster. The conversion factor is the electrical energy required to produce a unit of hydrogen output. If P_src is within the upper and lower power limits of the electrolyzer cluster, then P_tot_aim = P_src. If P_src is lower than the lower limit, then P_tot_aim is the lower power limit. If P_src is greater than the upper limit, then P_tot_aim is the upper power limit.

[0024] Furthermore, step S13 further includes the following steps:

[0025] Step S131: Suppose that there are N_starting electrolytic cells in the startup process and N_on electrolytic cells already in the running state. The N_starting electrolytic cells in the startup process execute the predetermined startup process first and are allocated the corresponding power. The allocated power is deducted from P_tot_aim, and the remaining power to be allocated is P_tot_aim2. P_tot_aim2 is allocated to the N_on electrolytic cells that are already in the running state to obtain the calculated target power P_indiv_aim for each electrolytic cell.

[0026] Step S132: Determine the maximum load P_indiv_max and minimum load P_indiv_min that a single electrolytic cell can achieve within the future time T1.

[0027] Step S133: Based on P_indiv_max and P_indiv_min, limit P_indiv_aim to obtain the target power P_indiv for each electrolytic cell, specifically:

[0028] If P_indiv_aim > P_indiv_max, then P_indiv = P_indiv_max;

[0029] If P_indiv_min≤P_indiv_aim≤P_indiv_max, then P_indiv=P_indiv_aim;

[0030] If P_indiv_aim < P_indiv_min, then P_indiv = P_indiv_min.

[0031] Further, in step S13, P_tot_aim2 is allocated to N_on electrolytic cells that are already in operation in an average distribution manner, and the calculated target power P_indiv_aim for each electrolytic cell is P_tot_aim2 / N_on.

[0032] Furthermore, step S25 further includes the following steps:

[0033] Step S251: Based on the safe operating range of a single electrolytic cell, the power operating range for n electrolytic cells is pre-selected as the interval PL(n) to PH(n), where n is the number of electrolytic cells in operation, n = 1, 2, 3...N, and N is the total number of electrolytic cells in the electrolytic cell cluster; assuming the operating load range of a single electrolytic cell is the interval PL_indiv to PH_indiv, then PL(n) = n*PL_indiv + ε, PH(n) = n*PH_indiv - ε, where ε is the margin taken based on the upper and lower limits of the operating load, ε ≥ 0;

[0034] Step S252: Select the optimal load rate r_opt based on the performance characteristics of a single electrolytic cell;

[0035] Step S253: If the weighted average power P_avg is within the range of PL(n) to PH(n) corresponding to the current number of electrolytic cells n, then the optimal number of electrolytic cells in operation n_on is the current number of electrolytic cells in operation n, and the electrolytic cell start-up and shutdown strategy is to not change the start-up and shutdown status of the electrolytic cell cluster; otherwise, the value of the optimal number of electrolytic cells in operation n_on is P_avg / (r_opt*P_nom) rounded down, where P_nom is the rated full-load power of a single electrolytic cell, and the difference between n_on and n is the number of cells that need to be started or shut down in the electrolytic cell start-up and shutdown strategy.

[0036] Furthermore, in step S251, calculations are performed in advance for all cases where the number of electrolytic cells n is 1 to N, forming a table showing the correspondence between PL(n) and PH(n) and n, which is stored in the control unit for querying.

[0037] Furthermore, in step S252, the optimal load rate r_opt is close to the optimal energy efficiency point of the electrolyzer, while maintaining adjustment space between the upper and lower limits of the safe operating range of a single electrolyzer.

[0038] Furthermore, the cycle T1 for load regulation of the electrolytic cell cluster is between 1 second and 1 minute, and the cycle T2 for updating the start-up and shutdown strategy of the electrolytic cell cluster is between 5 minutes and 1 hour; and / or, the cycle T2 for updating the start-up and shutdown strategy of the electrolytic cell cluster is more than 10 times the cycle T1 for load regulation of the electrolytic cell cluster.

[0039] Preferably, the cycle T2 for updating the start-up and shutdown strategy of the electrolytic cell cluster is an integer multiple of the cycle T1 for load regulation of the electrolytic cell cluster, and / or, the cycle T2 for updating the start-up and shutdown strategy of the electrolytic cell cluster is an integer multiple of the update cycle of the power generation prediction data of the power generation prediction unit.

[0040] According to some embodiments, the power generation unit is a wind power generation system, a photovoltaic power generation system, and / or a power generation system combining wind power generation and photovoltaic power generation.

[0041] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0042] The dual-cycle green electricity hydrogen production system electrolyzer cluster control method of this invention realizes the operation control mode in which the hydrogen production unit adjusts its workload in real time according to the renewable energy power generation unit. It solves the problem of large range and rapid change in wind and solar power output, gives full play to the advantage of the hydrogen production system in participating in the smoothing of power fluctuations, and plays a role in assisting the large-scale integration of renewable energy power generation units into the energy system. It significantly reduces the amount of electricity that needs to be obtained from the grid, effectively reduces electricity costs, realizes the real-time tracking of hydrogen production load with wind and solar power output, ensures the stable operation of the entire hydrogen production process system, and avoids frequent start-up and shutdown of electrolyzers, which helps to improve the life of electrolyzers. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of a green electricity hydrogen production system according to an embodiment of the present invention.

[0044] Figure 2 This is a flowchart of a control method according to an embodiment of the present invention. Detailed Implementation

[0045] This invention provides a real-time control technology for hydrogen production from renewable energy sources, specifically a dual-cycle green electricity hydrogen production system electrolyzer cluster control method. This method addresses the problems of poor control strategies in existing technologies and the additional costs caused by relying on the power grid or the start-up and shutdown of electrolyzers. It enables real-time tracking of hydrogen production load across a wide range of wind and solar power outputs, while also considering the lifespan of the electrolyzers and avoiding frequent start-ups and shutdowns.

[0046] Please see Figure 1 An embodiment of the present invention discloses a dual-cycle green electricity hydrogen production system electrolyzer cluster control method. The green electricity hydrogen production system mainly includes a power generation unit 1, a public power grid 2, a hydrogen production station auxiliary system 3 (electrical equipment other than the electrolyzer cluster), an electrolyzer cluster 4, a control unit 5, a hydrogen storage and usage unit 6, a first power measurement unit 7, a second power measurement unit 8, a third power measurement unit 9, and a power generation prediction unit 10. The power generation unit 1 is a renewable energy power generation system, such as a wind power generation system, a photovoltaic power generation system, and / or a power generation system combining wind and photovoltaic power generation.

[0047] The power generation unit 1 is connected to the public power grid 2, the hydrogen production station auxiliary system 3, and the electrolyzer cluster 4. The hydrogen outlet of the electrolyzer cluster 4 is connected to the hydrogen storage and usage unit 6. The power generation unit 1 is connected to the first power measurement unit 7, the hydrogen production station auxiliary system 3 is connected to the second power measurement unit 8, and the electrolyzer cluster 4 is connected to the third power measurement unit 9. The control unit 5 is connected to the first power measurement unit 7, the second power measurement unit 8, the third power measurement unit 9, the power generation prediction unit 10, and the electrolyzer cluster 4.

[0048] The above connections include electrical connections and wired / wireless communication connections, enabling the following functions to be achieved between the various parts: the power generation unit 1 generates electricity to supply the hydrogen production station auxiliary system 3 and the electrolyzer cluster 4; when the power generation of the power generation unit 1 is not equal to the power consumption of the hydrogen production station auxiliary system 3 and the electrolyzer cluster 4, the excess power is supplied to the public power grid 2, or conversely, the shortfall is made up by the public power grid 2; the first power measurement unit 7 measures the power generation of the power generation unit 1; the second power measurement unit 8 measures the power consumption of the hydrogen production station auxiliary system 3; the third power measurement unit 9 measures the power consumption of the electrolyzer cluster 4; the control unit 5 receives the power data measured by the first power measurement unit 7, the second power measurement unit 8, and the third power measurement unit 9, as well as the power generation prediction data from the power generation prediction unit 10, and formulates control strategies based on the data, and sends control commands to the electrolyzer cluster 4.

[0049] In the control method of this invention, two control cycles, T1 and T2, are selected. T1 is the cycle for load adjustment of the electrolytic cell cluster, and T2 is the cycle for updating the start-up and shutdown strategy of the electrolytic cell cluster. The electrolytic cell cluster updates its operating load every T1 time interval without changing the start-up and shutdown status of the electrolytic cells. Every T2, the start-up and shutdown strategy is updated, causing some electrolytic cells to start or shut down. The load level and start-up / shutdown decision of the electrolytic cells are determined by the control unit 5 after integrating the power data measured by the first power measurement unit 7, the second power measurement unit 8, and the third power measurement unit 9 (such as an instrument) and the power generation prediction data (externally provided) from the power generation prediction unit 10. The control cycles T1 and T2 are implemented, for example, by a timer in the control unit 5.

[0050] Please see Figure 2 An embodiment of the present invention provides a dual-cycle green electricity hydrogen production system electrolyzer cluster control method, which includes performing load adjustment every cycle T1 of the electrolyzer cluster load adjustment; when performing load adjustment, the control unit 5 determines the load level of the electrolyzer cluster 4 and issues control strategy instructions to the rectifier at the front end of the electrolyzer in the electrolyzer cluster 4 to perform adjustment.

[0051] The specific steps for load regulation are as follows: S11 to S14.

[0052] Step S11: Read and calculate the average available green electricity power over the past T1 time period; specifically, subtract the average power consumption of the hydrogen production station auxiliary system measured by the second power measurement unit 8 from the average power generation power measured by the first power measurement unit 7 over the past T1 time period to obtain the total available power P_src of the electrolyzer.

[0053] Step S12: Combine P_src and the hydrogen supply limit imposed by the hydrogen storage and utilization unit 6 (in other words, the hydrogen supply limit imposed by the downstream hydrogen storage or utilization stage) to obtain the target power P_tot_aim of the electrolyzer cluster (in other words, the total power to be consumed by the electrolyzer cluster).

[0054] More specifically, for example, in step S12, the calculation method for the target power P_tot_aim of the electrolytic cell cluster is as follows:

[0055] If there is no limit to the hydrogen supply, then P_tot_aim = P_src;

[0056] If there are limitations on the hydrogen supply, the acceptable upper and lower limits of hydrogen flow rate for the hydrogen storage and use unit are converted into the upper and lower limits of the electrolyzer cluster power. The conversion factor is the electrical energy required to produce a unit of hydrogen (the upper / lower limit of hydrogen flow rate multiplied by the conversion factor equals the upper / lower limit of the electrolyzer cluster power). If P_src is within the range of the upper and lower limits of the electrolyzer cluster power, then P_tot_aim = P_src. If P_src is lower than the lower limit, then P_tot_aim is the lower limit of power. If P_src is greater than the upper limit, then P_tot_aim is the upper limit of power.

[0057] Step S13: Allocate the target power P_tot_aim (in other words, the total power to be allocated) of the electrolytic cell cluster to each individual electrolytic cell. During allocation, first deduct the power required by the electrolytic cells that are starting up, and then allocate the remaining power to the electrolytic cells that are already in operation to obtain the adjustment target power P_indiv of each electrolytic cell, thus forming the electrolytic cell power adjustment strategy.

[0058] More specifically, for example, step S13 further includes the following steps:

[0059] Step S131: Suppose that there are N_starting electrolytic cells in the startup process and N_on electrolytic cells already in operation. The N_starting electrolytic cells in the startup process execute the predetermined startup process first and are allocated corresponding power (or power). The power value can be calculated or obtained by looking up a table according to the startup process. The allocated power is deducted from P_tot_aim, and the remaining power to be allocated is P_tot_aim2. P_tot_aim2 is allocated to the N_on electrolytic cells that are already in operation according to certain rules to obtain the calculated target power P_indiv_aim for each electrolytic cell.

[0060] One possible allocation rule is to allocate P_tot_aim2 to N_on electrolytic cells that are already in operation in an average manner, with the calculated target power P_indiv_aim for each electrolytic cell being P_tot_aim2 / N_on; other allocation rules may also be used.

[0061] Step S132: Determine the maximum load P_indiv_max and minimum load P_indiv_min that a single electrolytic cell can achieve within the future time T1. This requires considering the upper and lower limits of the operating load range of a single electrolytic cell, which can be obtained directly from the electrolytic cell performance parameter table. On the other hand, it requires considering the load adjustment speed of the electrolytic cell. The current power load of each electrolytic cell needs to be measured, and the maximum and minimum loads that can be achieved within the future time T1 are calculated in combination with the allowable load adjustment speed.

[0062] Step S133: Based on P_indiv_max and P_indiv_min, limit P_indiv_aim to obtain the target power P_indiv for each electrolytic cell, specifically:

[0063] If P_indiv_aim > P_indiv_max, then P_indiv = P_indiv_max;

[0064] If P_indiv_min≤P_indiv_aim≤P_indiv_max, then P_indiv=P_indiv_aim;

[0065] If P_indiv_aim < P_indiv_min, then P_indiv = P_indiv_min.

[0066] Step S14: The electrolytic cell power adjustment strategy is sent to the rectifiers at the front end of the electrolytic cells in the electrolytic cell cluster 4 for execution: the prescribed startup process is executed for the N_starting electrolytic cells in the startup process, and the power of the N_on electrolytic cells that are already in the running state is adjusted to the corresponding P_indiv.

[0067] The dual-cycle green electricity hydrogen production system electrolyzer cluster control method of the present invention further includes updating the electrolyzer cluster start-up and shutdown strategy every cycle T2 of the cycle. The update of the electrolyzer cluster start-up and shutdown strategy is prioritized before load regulation; that is, if the time for updating the electrolyzer cluster start-up and shutdown strategy overlaps with the time for load regulation, the electrolyzer cluster start-up and shutdown strategy is updated first, and then load regulation is performed.

[0068] Updating the start-up and shutdown strategy for the electrolytic cell cluster includes the following steps S21 to S26.

[0069] Step S21: Read and calculate the average available green electricity power over the past T2 time period; specifically, subtract the average power generation power measured by the first power measurement unit 7 from the average power consumption of the hydrogen production station auxiliary system measured by the second power measurement unit 8 over the past T2 time period to obtain the first average available green electricity power P_avg1.

[0070] Step S22: Read and calculate the average available green power from the past 2*T2 to the past T2 time period (i.e., the previous T2 period) to obtain the zeroth average available green power P_avg0, and then obtain the second average available green power P_avg2 = 2*P_avg1 - P_avg0.

[0071] Step S23: Read the predicted power generation data P_avg3 for the next time period T2.

[0072] Step S24: Calculate the weighted average power P_avg = a*P_avg1 + b*P_avg2 + (1-ab)*P_avg3 by combining P_avg1, P_avg2, and P_avg3, where a is the first weighting coefficient and b is the second weighting coefficient. The values ​​of a and b can be adjusted according to the actual situation.

[0073] Step S25: Calculate the optimal number of electrolytic cells to operate, n_on, and formulate an electrolytic cell start-up and shutdown strategy.

[0074] More specifically, step S25 further includes the following steps:

[0075] Step S251: Based on the safe operating range of a single electrolytic cell, the power operating range for n electrolytic cells is pre-selected as the interval PL(n) to PH(n), where n is the number of electrolytic cells in operation, n = 1, 2, 3...N, and N is the total number of electrolytic cells in the electrolytic cell cluster; assuming the operating load range of a single electrolytic cell is the interval PL_indiv to PH_indiv, then PL(n) = n*PL_indiv + ε, PH(n) = n*PH_indiv - ε, where ε is the margin taken based on the upper and lower limits of the operating load, ε ≥ 0, and ε is not necessarily a constant, and appropriate values ​​can be selected for different numbers of cells n;

[0076] More preferably, in step S251, all cases where the number of electrolytic cells n to be turned on are calculated in advance, and a table of the correspondence between PL(n) and PH(n) and n is finally formed and stored in the control unit for subsequent querying, such as in step S253.

[0077] Step S252: Select the optimal load rate r_opt based on the performance characteristics of a single electrolytic cell;

[0078] More preferably, in step S252, the optimal load rate r_opt should be close to the optimal energy efficiency point of the electrolyzer, while maintaining a certain adjustment range from the upper and lower limits of the safe operating range of a single electrolyzer.

[0079] Step S253: If the weighted average power P_avg is within the range of PL(n) to PH(n) corresponding to the current number of electrolytic cells n (this range can be selected to include the two endpoint values), then the optimal number of electrolytic cells in operation n_on is the current number of electrolytic cells in operation n, and the electrolytic cell start-up and shutdown strategy is to not change the start-up and shutdown status of the electrolytic cell cluster; otherwise, the value of the optimal number of electrolytic cells in operation n_on is P_avg / (r_opt*P_nom) rounded down (e.g., rounded to the nearest integer), where P_nom is the rated full-load power of a single electrolytic cell, and the difference between n_on and n is the number of cells that need to be started or shut down in the electrolytic cell start-up and shutdown strategy.

[0080] Step S26: Send the electrolytic cell start-up and shutdown strategy to the electrolytic cell cluster for execution.

[0081] Furthermore, the cycle T2 for updating the start-up and shutdown strategy of the electrolyzer cluster is more than 10 times the cycle T1 for load regulation of the electrolyzer cluster, and the specific selection is determined according to the actual fluctuation characteristics of wind and solar power generation. According to some embodiments, the cycle T1 for load regulation of the electrolyzer cluster can be selected between 1 second and 1 minute, and the cycle T2 for updating the start-up and shutdown strategy of the electrolyzer cluster can be selected between 5 minutes and 1 hour. Preferably, for the convenience of program development, the cycle T2 for updating the start-up and shutdown strategy of the electrolyzer cluster is an integer multiple of the cycle T1 for load regulation of the electrolyzer cluster, and the cycle T2 for updating the start-up and shutdown strategy of the electrolyzer cluster is an integer multiple of the update cycle of the power generation prediction data of the power generation prediction unit.

[0082] In summary, the dual-cycle green electricity hydrogen production system electrolyzer cluster control method of this invention realizes the operation control mode in which the hydrogen production unit adjusts its workload in real time according to the renewable energy power generation unit. It solves the problem of large range and rapid change in wind and solar power output, fully leverages the advantage of the hydrogen production system in participating in the smoothing of power fluctuations, and plays a role in assisting the large-scale integration of renewable energy power generation units into the energy system. It significantly reduces the amount of electricity that needs to be obtained from the grid, effectively reduces electricity costs, and realizes real-time tracking of hydrogen production load with wide load range of wind and solar power output. This ensures the stable operation of the entire hydrogen production process system, while avoiding frequent start-ups and shutdowns of the electrolyzers, which helps to improve the lifespan of the electrolyzers.

Claims

1. A method for cluster control of electrolyzers in a dual-cycle green electricity hydrogen production system, characterized in that, The green electricity hydrogen production system it adopts includes a power generation unit, a public power grid, a hydrogen production station auxiliary system, an electrolyzer cluster, a control unit, a hydrogen storage and usage unit, and a power generation prediction unit. The power generation unit is connected to the public power grid, the hydrogen production station auxiliary system, and the electrolyzer cluster; the hydrogen outlet of the electrolyzer cluster is connected to the hydrogen storage and usage unit; the power generation unit is connected to the first power measurement unit, the hydrogen production station auxiliary system is connected to the second power measurement unit, and the electrolyzer cluster is connected to the third power measurement unit; the control unit is connected to the first power measurement unit, the second power measurement unit, the third power measurement unit, the power generation prediction unit, and the electrolyzer cluster. The power generation unit generates electricity to supply the auxiliary system of the hydrogen production station and the electrolyzer cluster. When the power generation of the power generation unit is not equal to the power consumption of the auxiliary system of the hydrogen production station and the electrolyzer cluster, the excess power is supplied to the public power grid, or the shortfall is made up by the public power grid. The first power measurement unit is used to measure the power generation of the power generation unit. The second power measurement unit is used to measure the power consumption of the auxiliary system of the hydrogen production station. The third power measurement unit is used to measure the power consumption of the electrolyzer cluster. The control unit is used to receive the power data measured by the first power measurement unit, the second power measurement unit, and the third power measurement unit, as well as the power generation prediction data from the power generation prediction unit, and formulate control strategies based on the data, and send control commands to the electrolyzer cluster. The dual-cycle green electricity hydrogen production system electrolyzer cluster control method includes: performing load adjustment every cycle T1 of the electrolyzer cluster load adjustment; during load adjustment, the control system determines the load level of the electrolyzer cluster and sends the result to the rectifier at the front end of the electrolyzers in the electrolyzer cluster for adjustment; the specific steps of load adjustment include the following: Step S11: Subtract the average power generation measured by the first power measurement unit from the average power consumption of the hydrogen production station auxiliary system measured by the second power measurement unit to obtain the total available power P_src of the electrolyzer. Step S12: Combine P_src and the hydrogen supply limit imposed by the hydrogen storage and usage unit to obtain the target power P_tot_aim of the electrolyzer cluster; Step S13: Allocate the target power P_tot_aim of the electrolytic cell cluster to a single electrolytic cell. During allocation, first deduct the power required by the electrolytic cell in startup, and then allocate the remaining power to the electrolytic cells that are already in operation to obtain the adjustment target power P_indiv of each electrolytic cell, thus forming an electrolytic cell power adjustment strategy. Step S14: The electrolytic cell power adjustment strategy is sent to the electrolytic cell cluster for execution: the prescribed startup process is executed for the electrolytic cells during startup, and the power of the electrolytic cells that are already in operation is adjusted to the corresponding P_indiv. The dual-cycle green electricity hydrogen production system electrolyzer cluster control method further includes updating the electrolyzer cluster start-stop strategy every T2 of the electrolyzer cluster start-stop strategy update cycle. If the time for updating the electrolytic cell cluster start-up and shutdown strategy overlaps with the time for load adjustment, the electrolytic cell cluster start-up and shutdown strategy should be updated first, followed by load adjustment. The specific steps for updating the electrolytic cell cluster start-up and shutdown strategy are as follows: Step S21: Subtract the average power generation measured by the first power measurement unit from the average power consumption of the hydrogen production station auxiliary system measured by the second power measurement unit to obtain the first average available green power P_avg1. Step S22: Read and calculate the average available green power from the past 2*T2 to the past T2 time period to obtain the zeroth average available green power P_avg0, and then obtain the second average available green power P_avg2=2*P_avg1-P_avg0; Step S23: Read the predicted power generation data P_avg3 for the next time period T2; Step S24, calculate the weighted average power P_avg=a*P_avg1+b*P_avg2+(1-ab)*P_avg3, where a is the first weighting coefficient and b is the second weighting coefficient; Step S25: Calculate the optimal number of electrolytic cells to operate, n_on, and formulate an electrolytic cell start-up and shutdown strategy; Step S26: Send the electrolytic cell start-up and shutdown strategy to the electrolytic cell cluster for execution.

2. The method for cluster control of electrolyzers in a dual-cycle green electricity hydrogen production system according to claim 1, characterized in that, In step S12, the specific method for calculating the target power P_tot_aim of the electrolytic cell cluster is as follows: If there is no limit to the hydrogen supply, then P_tot_aim = P_src; If there are limitations on the hydrogen supply, the acceptable hydrogen flow rate limits for the hydrogen storage and usage unit are converted into the upper and lower power limits of the electrolyzer cluster. The conversion factor is the electrical energy required to produce a unit of hydrogen output. If P_src is within the upper and lower power limits of the electrolyzer cluster, then P_tot_aim = P_src. If P_src is lower than the lower limit, then P_tot_aim is the lower power limit. If P_src is greater than the upper limit, then P_tot_aim is the upper power limit.

3. The method for cluster control of electrolyzers in a dual-cycle green electricity hydrogen production system according to claim 1, characterized in that, Step S13 further includes the following steps: Step S131: Suppose that there are N_starting electrolytic cells in the startup process and N_on electrolytic cells already in the running state. The N_starting electrolytic cells in the startup process execute the predetermined startup process first and are allocated corresponding power. The allocated power is deducted from P_tot_aim, and the remaining power to be allocated is P_tot_aim2. P_tot_aim2 is allocated to the N_on electrolytic cells that are already in the running state to obtain the calculated target power P_indiv_aim for each electrolytic cell. Step S132: Determine the maximum load P_indiv_max and minimum load P_indiv_min that a single electrolytic cell can achieve within the future time T1. Step S133: Based on P_indiv_max and P_indiv_min, limit P_indiv_aim to obtain the target power P_indiv for each electrolytic cell, specifically: If P_indiv_aim > P_indiv_max, then P_indiv = P_indiv_max; If P_indiv_min≤P_indiv_aim≤P_indiv_max, then P_indiv=P_indiv_aim; If P_indiv_aim < P_indiv_min, then P_indiv = P_indiv_min.

4. The method for cluster control of electrolyzers in a dual-cycle green electricity hydrogen production system according to claim 3, characterized in that, In step S13, P_tot_aim2 is allocated to N_on electrolytic cells that are already in operation in an average distribution manner. The calculated target power of each electrolytic cell is P_indiv_aim = P_tot_aim2 / N_on.

5. The method for cluster control of electrolyzers in a dual-cycle green electricity hydrogen production system according to claim 1, characterized in that, Step S25 further includes the following steps: Step S251: Based on the safe operating range of a single electrolytic cell, the power operating range for n electrolytic cells is pre-selected as the interval PL(n) to PH(n), where n is the number of electrolytic cells in operation, n = 1, 2, 3...N, and N is the total number of electrolytic cells in the electrolytic cell cluster; assuming the operating load range of a single electrolytic cell is the interval PL_indiv to PH_indiv, then PL(n) = n*PL_indiv + ε, PH(n) = n*PH_indiv - ε, where ε is the margin taken based on the upper and lower limits of the operating load, ε ≥ 0; Step S252: Select the optimal load rate r_opt based on the performance characteristics of a single electrolytic cell; Step S253: If the weighted average power P_avg is within the range of PL(n) to PH(n) corresponding to the current number of electrolytic cells n, then the optimal number of electrolytic cells in operation n_on is the current number of electrolytic cells in operation n, and the electrolytic cell start-up and shutdown strategy is to not change the start-up and shutdown status of the electrolytic cell cluster; otherwise, the value of the optimal number of electrolytic cells in operation n_on is P_avg / (r_opt*P_nom) rounded down, where P_nom is the rated full-load power of a single electrolytic cell, and the difference between n_on and n is the number of cells that need to be started or shut down in the electrolytic cell start-up and shutdown strategy.

6. The method for cluster control of electrolyzers in a dual-cycle green electricity hydrogen production system according to claim 5, characterized in that, In step S251, calculations are performed in advance for all cases where the number of electrolytic cells n is 1 to N, forming a table showing the correspondence between PL(n) and PH(n) and n, which is stored in the control unit for querying.

7. The method for cluster control of electrolyzers in a dual-cycle green electricity hydrogen production system according to claim 5, characterized in that, In step S252, the optimal load rate r_opt is close to the optimal energy efficiency point of the electrolyzer, while maintaining adjustment space between the upper and lower limits of the safe operating range of a single electrolyzer.

8. The method for controlling the cluster of electrolyzers in a dual-cycle green electricity hydrogen production system according to any one of claims 1-7, characterized in that, The cycle T1 for load regulation of the electrolytic cell cluster is between 1 second and 1 minute, and the cycle T2 for updating the start-up and shutdown strategy of the electrolytic cell cluster is between 5 minutes and 1 hour; and / or, the cycle T2 for updating the start-up and shutdown strategy of the electrolytic cell cluster is more than 10 times the cycle T1 for load regulation of the electrolytic cell cluster.

9. The method for controlling the cluster of electrolyzers in a dual-cycle green electricity-to-hydrogen system according to any one of claims 1-7, characterized in that, The cycle T2 for updating the start-up and shutdown strategy of the electrolytic cell cluster is an integer multiple of the cycle T1 for load regulation of the electrolytic cell cluster, and / or the cycle T2 for updating the start-up and shutdown strategy of the electrolytic cell cluster is an integer multiple of the update cycle of the power generation prediction data of the power generation prediction unit.

10. The method for cluster control of electrolyzers in a dual-cycle green electricity hydrogen production system according to any one of claims 1-7, characterized in that, The power generation unit is a wind power generation system, a photovoltaic power generation system, and / or a power generation system that combines wind power generation and photovoltaic power generation.

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