Wind-solar-electricity-energy storage-water electrolysis mixed hydrogen production integrated system

Abstract

The invention provides a wind-light-electricity-energy storage-water electrolysis mixed hydrogen production integrated system. The system comprises a wind power station, a photovoltaic power station, an electricity storage device, a control center, a rectifier, an ALK electrolytic bath, a PEM electrolytic bath and a hydrogen storage tank. The photovoltaic power station and the wind power station are both connected to a rectifier and are both connected to an electricity storage device; the electricity storage device is connected to the rectifier; the rectifier is respectively connected to the ALK electrolytic bath and the PEM electrolytic bath, and the ALK electrolytic bath and the PEM electrolytic bath are both connected to the hydrogen storage tank. The integrated system has high weather compatibility and flexibility and stability of system operation, the hydrogen production cost is effectively reduced, and the integrated system has wide market application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of water electrolysis hydrogen production, and specifically to an integrated system for wind photovoltaic power-energy storage-water electrolysis hybrid hydrogen production. Background Art

[0002] At present, among renewable energy sources, solar energy, wind energy and hydropower are the most widely used. However, due to the volatility and intermittency of solar energy and wind energy, the accessibility of power products in the power grid is poor, and there is a large amount of wind and solar power abandonment. In order to make more effective use of these green electric energies, water electrolysis hydrogen production technology is used to convert excess renewable electric energy into chemical energy that is easy to store and transport. When there is a power generation gap in renewable energy, chemical products can be used to generate electricity to achieve the effect of peak shaving and valley filling.

[0003] At present, the mature technologies for hydrogen production by water electrolysis include alkaline (ALK) water electrolysis and proton exchange membrane (PEM) water electrolysis. Among them, the single-tank hydrogen production capacity of alkaline electrolysis cells is high and the unit production capacity investment is low; the hydrogen production by water electrolysis by proton exchange membrane has the characteristics of fast load response speed, wide adjustment range, and strong anti-fluctuation ability, but the unit production capacity investment is high and the single-tank hydrogen production capacity is small. Summary of the invention

[0004] In order to solve the technical problems existing in the above-mentioned prior art, the present invention provides an integrated system for wind photovoltaic power-energy storage-water electrolysis hybrid hydrogen production that utilizes alkaline water electrolysis and proton exchange membrane water electrolysis to hybrid hydrogen production.

[0005] According to one aspect of the present invention, an integrated system for wind photovoltaic-energy storage-water electrolysis hybrid hydrogen production includes: a wind power station, a photovoltaic power station, a power storage device, a control center, a rectifier, an ALK electrolyzer, a PEM electrolyzer and a hydrogen storage tank; the photovoltaic power station and the wind power station are both connected to the rectifier and to the power storage device; the power storage device is connected to the rectifier; the rectifier is respectively connected to the ALK electrolyzer and the PEM electrolyzer, and the ALK electrolyzer and the PEM electrolyzer are both connected to the hydrogen storage tank.

[0006] In an example of the integrated system provided in the above aspect, the control center is used to compare the power generation of the wind power station and the photovoltaic power station with the power required for hydrogen production; wherein, when the power generation of the wind power station and the photovoltaic power station is greater than the power required for hydrogen production, the control center is also used to control the transmission of excess electricity of the wind power station and / or the photovoltaic power station to the power storage device.

[0007] In an example of the integrated system provided in the above aspect, when the power generation of the wind power station and the photovoltaic power station is less than the power required for hydrogen production, the control center is also used to compare the power generation of the wind power station and the photovoltaic power station with the minimum power required for hydrogen production; wherein, when the power generation of the wind power station and the photovoltaic power station is greater than the minimum power required for hydrogen production, the control center is also used to control the transmission of electricity from the wind power station and the photovoltaic power station to the ALK electrolyzer and / or the PEM electrolyzer through the rectifier.

[0008] In an example of the integrated system provided in the above aspect, when the power generation of the wind power station and the photovoltaic power station is less than the minimum power required for hydrogen production, the control center is also used to control the power storage device to transmit electricity to the ALK electrolyzer and / or the PEM electrolyzer through the rectifier.

[0009] In an example of the integrated system provided in the above aspect, the control center is also used to determine the input power required for each of the ALK electrolyzer and the PEM electrolyzer based on the unit cost of hydrogen production, the hydrogen production rate, and constraint variables, so as to maximize the operating profit of the integrated system; wherein the constraint variables include: wind turbine predicted power generation constraint, photovoltaic predicted power generation constraint, power storage device power constraint, ALK electrolyzer operating power constraint, and PEM electrolyzer operating power constraint.

[0010] In an example of the integrated system provided in the above aspect, the control center is also used to control the rectifier to adjust the amount of electricity delivered to the ALK electrolyzer and the PEM electrolyzer according to the determined input power required by each of the ALK electrolyzer and the PEM electrolyzer.

[0011] In an example of the integrated system provided in the above aspect, the ALK electrolyzer includes multiple ALK sub-electrolyzers, and the PEM electrolyzer includes multiple PEM sub-electrolyzers; the control center is also used to control the amount of electricity delivered by the rectifier to each ALK sub-electrolyzer and each PEM sub-electrolyzer.

[0012] In an example of the integrated system provided in the above aspect, when the temperature of the ALK sub-electrolyzer or the PEM sub-electrolyzer is greater than the thermal neutral temperature corresponding to the neutral voltage of the electrolyzer, the control center controls the voltage delivered by the rectifier to the corresponding ALK sub-electrolyzer or PEM sub-electrolyzer to decrease; when the temperature of the ALK sub-electrolyzer or the PEM sub-electrolyzer is less than the thermal neutral temperature corresponding to the neutral voltage of the electrolyzer, the control center controls the voltage delivered by the rectifier to the corresponding ALK sub-electrolyzer or PEM sub-electrolyzer to increase.

[0013] In an example of the integrated system provided in the above aspect, the control center is also used to obtain the number of open ALK sub-electrolyzers based on the allocated power of the ALK electrolyzer and the efficiency excellence range of the ALK electrolyzer, and is also used to calculate the hydrogen production amount, hydrogen production efficiency and hydrogen production cost of each opened ALK sub-electrolyzer, and is also used to allocate the allocated power of the ALK electrolyzer to each opened ALK sub-electrolyzer based on the calculated hydrogen production amount, hydrogen production efficiency and hydrogen production cost.

[0014] In an example of the integrated system provided in the above aspect, the control center is also used to obtain the number of PEM sub-electrolyzers to be opened based on the allocated power of the PEM electrolyzer and the efficiency excellence interval of the PEM electrolyzer, and is also used to calculate the hydrogen production amount, hydrogen production efficiency and hydrogen production cost of each opened PEM sub-electrolyzer, and is also used to allocate the allocated power of the PEM electrolyzer to each opened PEM sub-electrolyzer based on the calculated hydrogen production amount, hydrogen production efficiency and hydrogen production cost.

[0015] Beneficial effects: The integrated system of the present invention will have high weather compatibility, flexibility and stability in system operation, effectively reduce the cost of hydrogen production, and has broad market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other aspects, features and advantages of the embodiments of the present invention will become more apparent through the following description in conjunction with the accompanying drawings, in which:

[0017] Figure 1 is a schematic diagram of an integrated system for wind photovoltaic power generation-energy storage-water electrolysis hybrid hydrogen production according to an embodiment of the present invention;

[0018] Figure 2 is a control flow chart of an integrated system for wind photovoltaic power generation-energy storage-water electrolysis hybrid hydrogen production according to an embodiment of the present invention;

[0019] Figure 3 is a schematic diagram of the composition of an ALK electrolyzer and a PEM electrolyzer according to an embodiment of the present invention;

[0020] Figure 4 is a control flow chart of an ALK electrolyzer and a PEM electrolyzer according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention may be implemented in many different forms, and the present invention should not be construed as being limited to the specific embodiments set forth herein. On the contrary, these embodiments are provided to explain the principles of the present invention and their practical applications, so that other persons skilled in the art can understand the various embodiments of the present invention and various modifications suitable for specific intended applications.

[0022] As used herein, the term "including" and its variations represent open terms, meaning "including but not limited to". The terms "based on", "according to", etc. mean "based at least in part on", "based at least in part on". The terms "one embodiment" and "an embodiment" mean "at least one embodiment". The term "another embodiment" means "at least one other embodiment". The terms "first", "second", etc. may refer to different or the same objects. Other definitions may be included below, whether explicit or implicit. Unless the context clearly indicates otherwise, the definition of a term is consistent throughout the specification.

[0023] The terms "exemplary," "example," and the like used throughout this specification mean "used as an example, instance, or illustration" and do not mean "preferred" or "advantageous" over other embodiments. The detailed description includes specific details for the purpose of providing an understanding of the described techniques. However, these techniques can be implemented without these specific details. In some instances, in order to avoid obscuring the concepts of the described embodiments, well-known structures and devices are shown in block diagram form.

[0024] Figure 1 It is a schematic diagram of an integrated system for wind photovoltaic power-energy storage-water electrolysis hybrid hydrogen production according to an embodiment of the present invention.

[0025] Reference Figure 1 According to an embodiment of the present invention, the integrated system of wind-photovoltaic-energy storage-water electrolysis hybrid hydrogen production includes wind power (i.e. wind power station), photovoltaic (i.e. photovoltaic power station), power storage device (or power storage device), control cabinet (i.e. control center), rectifier, ALK (i.e. ALK electrolyzer), PEM (i.e. PEM electrolyzer) and hydrogen storage tank.

[0026] Specifically, the photovoltaic power station and the wind power station are connected to the rectifier and the power storage device; the power storage device is connected to the rectifier and outputs to the rectifier; the rectifier is connected to the ALK electrolyzer and the PEM electrolyzer, and the ALK electrolyzer and the PEM electrolyzer are respectively connected to the hydrogen storage tanks; the control center controls the electric energy from the photovoltaic power station and the wind power station to the power storage device and the rectifier, as well as the power characteristics of the rectifier output to the ALK electrolyzer and the PEM electrolyzer, and receives feedback signals from the photovoltaic power station, the wind power station, the ALK electrolyzer and the PEM electrolyzer.

[0027] Furthermore, the control center includes charging and discharging strategies of photovoltaic power stations, wind power stations and power storage devices, voltage-current regulation strategies of rectifiers and ALK electrolyzers, and PEM electrolyzers, and multi-objective optimization and control strategies of integrated systems.

[0028] In addition, the four subsystem components of the integrated system, namely wind power, photovoltaic power, energy storage and hydrogen production, can be configured with capacity after target optimization based on the implementation site's annual weather changes, hydrogen production demand, investment and operating costs, and environmental benefits.

[0029] The charging and discharging strategies of the wind power, photovoltaic and energy storage devices of this integrated system mainly include two points: one is to ensure that the temperature of the electrolyzer (i.e. ALK electrolyzer and PEM electrolyzer) operates in the excellent efficiency range; the other is to ensure that the electrolyzer can operate continuously for a long time, that is, it can operate stably in cloudy, rainy, night and other weather conditions.

[0030] The voltage-current regulation strategy of the rectifier and electrolyzer of the integrated system is to make real-time fine adjustments based on the deviation between the actual voltage and current of the electrolyzer and the ideal voltage and current, so as to reduce polarization losses and battery temperature rise caused by excessive voltage, and avoid the decline in hydrogen production performance of the integrated system and parameter oscillation of the integrated system caused by excessively low voltage.

[0031] The control center of the integrated system needs to monitor the operating parameters of each subsystem in real time throughout the entire process. After multi-objective optimization using a neural network algorithm, it will adjust the power supply ratios of wind power, photovoltaic power and energy storage devices, electrolyzers, energy storage devices and electrolyzers, and the voltage-current power supply of rectifiers and electrolyzers in real time.

[0032] Figure 2 This is a control flow chart of an integrated system for wind photovoltaic power generation, energy storage and water electrolysis for hydrogen production according to an embodiment of the present invention. It should be noted that the control strategy is executed by the control center.

[0033] Reference Figure 2 First, the power generated by the wind power station and photovoltaic power station is compared with the power required for hydrogen production. When the wind and photovoltaic power generation is greater than the power required for hydrogen production, the excess power is transmitted to the power storage device. When the wind and photovoltaic power generation is less than the power required for hydrogen production, it is necessary to compare it with the minimum power used by the electrolyzer. At this time, if the wind and photovoltaic power generation is greater than the minimum power used by the electrolyzer, the power generated by the wind power station and photovoltaic power station is supplied to the electrolyzer through the rectifier; if the wind and photovoltaic power generation is less than the minimum power used by the electrolyzer, it is also necessary to output electric energy to the rectifier through the power storage device to compensate for the wind and photovoltaic power generation, so as to be used for water electrolysis to produce hydrogen.

[0034] In addition, the required electric energy supplied by the rectifier of the integrated system to the electrolyzer was predicted through multi-objective optimization, mainly including the unit cost of hydrogen production and the hydrogen production rate; and the constraint variables involved included the predicted value of wind and solar power generation, the storage capacity of the power storage device, the excellent range of hydrogen production efficiency of the electrolyzer, and the global power balance constraint of the system.

[0035] Among them, the integrated system operation benefits are maximized:

[0036] Among them, I (t) is the unit cost of hydrogen production, m (t) is the hydrogen production rate, C1 and C2 are evaluation coefficients. The above formula represents the maximized comprehensive benefit of the integrated system in hydrogen production when the electrolyzer operates continuously for a period of time.

[0037] Wind turbine forecast power generation constraints: in, They are the upper and lower limits of the fan output power in a certain period of time.

[0038] Photovoltaic forecast power generation constraints: In the formula, They are the upper and lower limits of photovoltaic output power in a certain period of time.

[0039] Power storage device capacity limit: in, They are respectively the upper and lower limits of the power of the power storage device in a certain period of time.

[0040] ALK electrolyzer operating power constraints: in, They are the upper and lower limits of the normal operation of the ALK electrolyzer.

[0041] PEM electrolyzer operating power constraints: in, They are the upper and lower limits of normal operation of the PEM electrolyzer.

[0042] The multi-objective algorithm used by the control center of the integrated system in the multi-objective optimization scheduling of this process is the multi-objective golden eagle optimizer (MOGEO), which has the characteristics of fast convergence speed and strong optimization ability.

[0043] The integrated system determines the water electrolysis input power at a certain moment (i.e., the total power required for hydrogen production by water electrolysis) through a multi-objective optimization method, including the power allocation ratio of the ALK electrolyzer and the PEM electrolyzer.

[0044] Afterwards, the control center of the integrated system will adjust the voltage-current delivered to different electrolyzers through rectifiers. Among them, the ALK electrolyzer and PEM electrolyzer are both combinations formed by multiple sub-electrolyzers. For details, please refer to Figure 3 .

[0045] Specifically, in response to the input voltage-current, the ALK electrolyzer and the PEM electrolyzer will undergo electrochemical reactions and heat and mass transfer, which is a multi-time scale process with slow changes in heat and mass.

[0046] The temperature change of the electrolytic cell is measured by the thermocouple, and the temperature measurement value is fed back to the control center, and the control center readjusts the voltage and current values ​​input to each electrolytic cell by the rectifier according to the temperature and temperature change rate of the electrolytic cell.

[0047] The voltage and current regulation strategy of the rectifier is: when the cell temperature exceeds the thermal neutral temperature corresponding to the neutral voltage of the cell, the rectifier regulation will reduce the voltage; when the cell temperature is lower than the thermal neutral temperature corresponding to the neutral voltage of the cell, the rectifier regulation will increase the voltage. In addition, the speed of the temperature change rate can be adjusted by changing the function curve of the rectifier output voltage, such as a sine function, a step function, etc.

[0048] Reference Figure 3 , both the ALK electrolyzer and the PEM electrolyzer are composed of multiple sub-electrolyzers. Therefore, the power distribution of the sub-electrolyzers can be evenly distributed or unevenly distributed, that is, the power sizes of the sub-electrolyzers are inconsistent.

[0049] When the input power of water electrolysis is sufficient, evenly distributing the power of the sub-electrolyzers can make each sub-electrolyzer operate in an excellent efficiency range; when the input power of water electrolysis is insufficient, in order to ensure that the sub-electrolyzers operate in an excellent efficiency range, only some of the sub-electrolyzers can be turned on.

[0050] Therefore, in the sub-electrolyzer non-uniform power allocation model, the power allocation of the sub-electrolyzers is based on the hydrogen production efficiency and cost optimization of the ALK electrolyzer and the PEM electrolyzer. Some sub-electrolyzers can be selectively shut down, and the remaining sub-electrolyzers can be kept operating in a high operating efficiency range. The performance of the sub-electrolyzers can be monitored and evaluated in real time, and the operating efficiency range of the sub-electrolyzers can be modified, and then fed back to the control center for strategic decision-making.

[0051] Maximizing profitability of ALK and PEM electrolyzer operations: Where, m and n are the number of opened sub-electrolyzers in the ALK electrolyzer and the PEM electrolyzer, respectively. Figure 4 is a control flow chart of an ALK electrolyzer and a PEM electrolyzer according to an embodiment of the present invention.

[0052] Reference Figure 4 When performing optimization calculations, the allocated power of the ALK electrolyzer is divided by the excellent efficiency range of its sub-electrolyzers to obtain the excellent number of sub-electrolyzers that are opened. The hydrogen production, efficiency and cost of different numbers of sub-electrolyzers that are opened are calculated under the allocated power, and the optimal number of sub-electrolyzers opened and the voltage-current are fed back to the control center.

[0053] Similarly, the allocated power of the PEM electrolyzer is divided by the excellent efficiency range of its sub-electrolyzers to obtain the excellent number of sub-electrolyzers to be opened. The hydrogen production, efficiency and cost of different numbers of sub-electrolyzers opened under the allocated power are calculated, and the optimal number of sub-electrolyzers opened and the voltage-current are fed back to the control center.

[0054] Continue to refer to Figure 1 The hydrogen production of ALK and PEM electrolyzers is used to calculate the deviation between the hydrogen production cost of the integrated system and the hydrogen production demand of the integrated system, and the feedback is sent to the control center. The control center verifies whether the error range is met; if not, the control center optimizes and regulates the operation of the integrated system again through multi-objective optimization.

[0055] The following is a specific application example of an integrated system for wind photovoltaic power generation-energy storage-water electrolysis hybrid hydrogen production according to an embodiment of the present invention.

[0056] Application Example 1

[0057] The integrated system was put into operation in the morning when the weather was clear and the wind speed was level 3. At this time, the control center compared the wind and solar power generation with the normal working power of the electrolyzer hydrogen production system. The power generation was within the normal working range of the electrolyzer; therefore, all the wind and solar power generation was transmitted to the water electrolysis system, and the rectifier provided the electrolyzer with voltage and current that met the temperature conditions. At this time, the electrolyzer started slowly and gradually reached a stable state. Among them, when the average power distribution is not enough to allow the sub-electrolyzer to work in the high efficiency range, only some of the sub-electrolyzers can be turned on.

[0058] As the amount of wind and solar power generation continues to increase, the rectifier also continuously adjusts the voltage and current values ​​transmitted to the electrolyzer, and can increase the sub-electrolyzers that are not turned on to share the excess power and ensure that it is in the best working range. At a certain point, the wind and solar power generation exceeds the power required for the normal operation of the electrolyzer. At this time, the control center adjusts the excess power of wind and solar power generation to be transmitted to the power storage device and stored.

[0059] As the sun sets, the photovoltaic power generation decreases to zero, and at this time, wind power is responsible for the electricity required for the electrolyzer to work. When wind power is not enough to maintain the normal operation of the electrolyzer, the control center will control the output power of the power storage device to the electrolyzer based on the power generation of the wind power station at night, the power of the power storage device, and the demand for hydrogen. The output power of the power storage device is determined by optimizing the two goals of the excellent range of normal operation efficiency of the electrolyzer and the cost of hydrogen production.

[0060] Application Example 2

[0061] After the integrated system has been operating normally for a period of time, the control center predicts that rainy weather will occur in the next few days. At this time, in order to ensure the normal operation of the water electrolysis system (i.e., the system composed of ALK and PEM electrolyzers) and the necessary hydrogen production, the control center will calculate the adjustment strategy of the power storage device in the next few days through multi-objective optimization. The time of rainy weather, the predicted value of wind power station power generation during rainy weather, and the storage capacity of the power storage device before the rainy weather are used as constraints, and the cost and amount of hydrogen production before the rainy weather, and the maximum benefit of the cost and amount of hydrogen production during the rainy weather are used as objective functions to control the electrolyzer operation scheduling strategy before the rainy weather and the operation scheduling strategy during the rainy weather. In the subsequent operation of the system, the predicted value of wind and solar power generation will be corrected in real time, the system scheduling strategy will be verified, and the operation strategy of the water electrolysis hydrogen production process will be corrected in real time.

[0062] In summary, the integrated system according to the embodiment of the present invention realizes the continuous hydrogen production of the water electrolysis system under different weather conditions through the coupling of wind and solar power generation and power storage devices; through the coupling regulation of wind and solar power generation, power storage capacity of power storage devices and electrolysis characteristics of alkaline electrolyzers and proton exchange membrane electrolyzers, the defects of wind and solar renewable energy in terms of intermittency and volatility are suppressed or eliminated; the control center regulates and optimizes the operation strategy of the system to ensure the comprehensive optimal performance of the electrolysis hydrogen production process in terms of operating cost, hydrogen production efficiency and equipment attenuation. Furthermore, the integrated system according to the embodiment of the present invention will have high weather compatibility, flexibility and stability of system operation, effectively reduce the cost of hydrogen production, and have broad market application prospects.

[0063] The optional implementation modes of the embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above implementation modes. Within the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all belong to the protection scope of the embodiments of the present invention.

Claims

1. An integrated system of wind power generation, photovoltaic power generation, energy storage and water electrolysis for hydrogen production, characterized in that: The integrated system includes: a wind power station, a photovoltaic power station, a power storage device, a control center, a rectifier, an ALK electrolyzer, a PEM electrolyzer and a hydrogen storage tank; The photovoltaic power station and the wind power station are both connected to a rectifier and to a power storage device; the power storage device is connected to a rectifier; the rectifier is respectively connected to the ALK electrolyzer and the PEM electrolyzer, and the ALK electrolyzer and the PEM electrolyzer are both connected to the hydrogen storage tank.

2. The integrated system according to claim 1, characterized in that: The control center is used to compare the power generation of the wind power station and the photovoltaic power station with the power required for hydrogen production; When the power generation of the wind power station and the photovoltaic power station is greater than the power required for hydrogen production, the control center is also used to control the transmission of excess power of the wind power station and / or the photovoltaic power station to the power storage device.

3. The integrated system according to claim 2, characterized in that: When the power generation of the wind power station and the photovoltaic power station is less than the power required for hydrogen production, the control center is further used to compare the power generation of the wind power station and the photovoltaic power station with the minimum power required for hydrogen production; When the power generation of the wind power station and the photovoltaic power station is greater than the minimum power required for hydrogen production, the control center is also used to control the transmission of the power of the wind power station and the photovoltaic power station to the ALK electrolyzer and / or the PEM electrolyzer through the rectifier.

4. The integrated system according to claim 3, characterized in that: When the power generation of the wind power station and the photovoltaic power station is less than the minimum power required for hydrogen production, the control center is also used to control the power storage device to transmit electricity to the ALK electrolyzer and / or the PEM electrolyzer through the rectifier.

5. The integrated system according to claim 4, characterized in that: The control center is also used to determine the input power required for each of the ALK electrolyzer and the PEM electrolyzer based on the unit cost of hydrogen production, the hydrogen production rate, and constraint variables to maximize the operating profit of the integrated system; wherein the constraint variables include: wind turbine predicted power generation constraint, photovoltaic predicted power generation constraint, power storage device power constraint, ALK electrolyzer operating power constraint, and PEM electrolyzer operating power constraint.

6. The integrated system according to claim 5, characterized in that: The control center is further used to control the rectifier to adjust the amount of electricity delivered to the ALK electrolyzer and the PEM electrolyzer according to the determined input power required by the ALK electrolyzer and the PEM electrolyzer respectively.

7. The integrated system according to claim 6, characterized in that: The ALK electrolyzer includes a plurality of ALK sub-electrolyzers, and the PEM electrolyzer includes a plurality of PEM sub-electrolyzers; the control center is also used to control the amount of electricity delivered by the rectifier to each ALK sub-electrolyzer and each PEM sub-electrolyzer.

8. The integrated system according to claim 7, characterized in that: When the temperature of the ALK sub-electrolyzer or the PEM sub-electrolyzer is greater than the thermal neutral temperature corresponding to the neutral voltage of the electrolyzer, the control center controls the voltage delivered by the rectifier to the corresponding ALK sub-electrolyzer or PEM sub-electrolyzer to decrease; when the temperature of the ALK sub-electrolyzer or the PEM sub-electrolyzer is less than the thermal neutral temperature corresponding to the neutral voltage of the electrolyzer, the control center controls the voltage delivered by the rectifier to the corresponding ALK sub-electrolyzer or PEM sub-electrolyzer to increase.

9. The integrated system according to claim 7, characterized in that: The control center is also used to obtain the number of ALK sub-electrolyzers to be opened based on the allocated power of the ALK electrolyzer and the efficiency excellence range of the ALK electrolyzer, and is also used to calculate the hydrogen production amount, hydrogen production efficiency and hydrogen production cost of each opened ALK sub-electrolyzer, and is also used to allocate the allocated power of the ALK electrolyzer to each opened ALK sub-electrolyzer based on the calculated hydrogen production amount, hydrogen production efficiency and hydrogen production cost.

10. The integrated system according to claim 7, characterized in that: The control center is also used to obtain the number of PEM sub-electrolyzers to be opened according to the power allocated to the PEM electrolyzer and the efficiency excellence interval of the PEM electrolyzer, and is also used to calculate the hydrogen production amount, hydrogen production efficiency and hydrogen production cost of each opened PEM sub-electrolyzer, and is also used to distribute the allocated power of the PEM electrolyzer to each opened PEM sub-electrolyzer according to the calculated hydrogen production amount, hydrogen production efficiency and hydrogen production cost.

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