New energy electrolytic hydrogen production alternating current island system and frequency control method thereof

Abstract

The invention discloses a new energy electrolytic hydrogen production alternating current island system and a frequency control method thereof. The alternating current island system comprises a new energy power supply, an alternating current power grid, a power electronic rectifier, an electrolytic cell group, an energy storage device, a frequency monitoring unit and a control unit, the control unit generates a corresponding control signal according to a preset rule by taking the system frequency data acquired by the frequency monitoring unit as a parameter; the preset rule comprises the steps of generating a control signal of the power electronic rectifier according to a preset analog control strategy; the simulation control strategy is generated according to power and frequency response characteristics corresponding to the electrolytic cell group; when the fluctuation amplitude of the system frequency is larger than a preset threshold value, the fluctuation amplitude of the system frequency is reduced by executing charging and discharging actions of an electrolytic bath in the energy storage device; the self-adaptive frequency control is carried out through the power of the electrolytic cell by using the power electronic rectifier, so that a better frequency control effect and lower energy storage cost can be obtained.

Description

Technical Field

[0001] The present invention relates to the field of power systems, and in particular to an AC island system for hydrogen production using electrolysis from a new energy source and a frequency control method thereof. Background Art

[0002] Green hydrogen production from renewable energy sources has received significant attention as a future direction for clean energy development. Generally, to ensure the safety of green hydrogen projects, ensure electrolyzer shutdowns and power balance, and maintain grid-connected operation, large-scale energy storage and energy management platforms are required for isolated operation.

[0003] In traditional power systems, synchronous generators generally have automatic droop characteristics, and the load power of motor-driven machinery such as compressors, fans, and pumps is positively correlated with the speed / frequency. Therefore, system frequency regulation for short-term or small disturbances can be achieved through automatic feedback, while longer-term power differences are achieved through AGC secondary frequency regulation or scheduling.

[0004] In AC power systems dominated by new energy, with the massive access of new energy and the construction of high-voltage direct current interconnected systems, the constant power control mode of power electronic converters has led to a serious reduction in the correlation between the power of power supplies, loads and other equipment and the system frequency, manifesting as increasingly weak frequency regulation capabilities. Therefore, the frequency stability problem of AC island systems for hydrogen production using electrolysis of new energy has become increasingly serious. In existing technologies, when a new power system is disturbed, the frequency stability of the new power system is generally controlled by switching on and off the energy storage units in the new power system.

[0005] After research, the inventors found that the existing AC island system for new energy electrolysis hydrogen production still has at least the following defects:

[0006] The new energy electrolysis hydrogen production AC island system uses energy storage unit charging and discharging and electrolyzer switching to cope with system frequency disturbances, which has poor timeliness and effectiveness.

[0007] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0008] The purpose of the present invention is to be able to timely and effectively control the frequency of the new energy electrolysis hydrogen production AC island system and improve the control effect.

[0009] The present invention provides a new energy electrolysis hydrogen production AC island system, comprising a new energy power supply, an AC power grid, a power electronic rectifier, an electrolyzer group, an energy storage device, a frequency monitoring unit and a control unit;

[0010] The control unit uses the system frequency data collected by the frequency monitoring unit as a parameter and generates a corresponding control signal according to a preset rule; the preset rule includes:

[0011] generating a control signal for the power electronic rectifier according to a preset analog control strategy; wherein the analog control strategy is generated according to power and frequency response characteristics corresponding to the electrolytic cell group;

[0012] When the fluctuation amplitude of the system frequency is greater than a preset threshold, the fluctuation amplitude of the system frequency is reduced by executing the charging and discharging actions of the energy storage device.

[0013] In an embodiment of the present invention, a frequency control method for an AC island system for hydrogen production by electrolysis of a new energy source is also provided. The AC island system for hydrogen production by electrolysis of a new energy source includes a new energy power supply, an AC power grid, a power electronic rectifier, an electrolyzer group, an energy storage device, a frequency monitoring unit, and a control instruction unit. The method is characterized in that it includes the following steps:

[0014] S11. Acquire the system frequency of the new energy electrolysis hydrogen production AC island system in real time;

[0015] S12. Using the current system frequency as a parameter, generating a control signal for the power electronic rectifier according to a preset analog control strategy; the analog control strategy is generated according to power and frequency response characteristics corresponding to the electrolytic cell group;

[0016] S13. When the fluctuation amplitude of the system frequency is greater than a preset threshold, reducing the fluctuation amplitude of the system frequency by executing charging and discharging actions of the energy storage device.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The new energy electrolysis hydrogen production AC island system in the present invention utilizes the characteristic that its electrolyzer group can accept a wider range of power fluctuations. When a small system frequency disturbance occurs, the power of the electrolyzer group is adjusted by the power electronic rectifier to achieve a rapid response to the system frequency disturbance; specifically, in the present invention, when the fluctuation amplitude of the system frequency is a small disturbance (that is, the fluctuation amplitude is less than a preset threshold), the power of the electrolyzer group is adjusted by the power electronic rectifier to achieve a small adjustment of the system frequency; then, when the fluctuation amplitude of the system frequency is large (that is, the fluctuation amplitude is greater than the preset threshold), the system frequency is stabilized by the charge and discharge control method of the energy storage device.

[0019] As can be seen from the above, the present invention classifies the disturbances. In this way, when subjected to a small disturbance, the power adjustment unit is used to adjust the power of the electrolytic cell group according to the analog control strategy, thereby indirectly adjusting the system frequency. Since the adjustment amplitude of the power of the electrolytic cell group is controllable, the present invention can achieve flexible adjustment of the system frequency through moderate adjustment of the power. Compared with the charging and discharging control method of the energy storage device, the power adjustment method of the electrolytic cell group in the present invention can avoid the secondary disturbance of the system frequency caused by the charging and discharging action of the energy storage device, thereby achieving better adjustment effect in the case of small system disturbances.

[0020] On the other hand, the traditional method of regulating system frequency through charging and discharging control of energy storage devices still has the defect of too long response time; the present invention can achieve millisecond-level response to system disturbances through power electronic rectifiers, and thus can also effectively reduce the negative impact of disturbances on the new energy electrolysis hydrogen production AC island system.

[0021] On the other hand, in the present invention, when there is a small system disturbance, the system frequency is no longer adjusted by the charge and discharge control of the energy storage device, which can greatly reduce the charge and discharge frequency of the energy storage device, thereby effectively increasing the service life of the energy storage device.

[0022] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other purposes, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 This is a structural diagram of the AC island system for producing hydrogen through electrolysis using new energy in the present invention;

[0025] Figure 2 It is a schematic diagram of the steps of the frequency control method of the AC island system for hydrogen production by electrolysis of new energy in the present invention. DETAILED DESCRIPTION

[0026] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0027] Unless expressly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising” will be understood to include the stated elements or components but not to exclude other elements or components.

[0028] In this document, the terms "first", "second", etc. are used to distinguish two different elements or parts, and are not used to limit specific positions or relative relationships. In other words, in some embodiments, the terms "first", "second", etc. can also be interchangeable with each other.

[0029] Example 1

[0030] In order to be able to control the system frequency in a timely and effective manner and improve the control effect, refer to Figure 1 , an embodiment of the present invention provides a new energy electrolysis hydrogen production AC island system, including a new energy power supply 01, an AC power grid 02, a power electronic rectifier 03, an electrolyzer group 04, an energy storage device 05, a frequency monitoring unit 06 and a control unit 07;

[0031] The control unit 07 uses the system frequency data collected by the frequency monitoring unit 06 as a parameter and generates a corresponding control signal according to preset rules; the preset rules include:

[0032] Generate a control signal for the power electronic rectifier 03 according to a preset analog control strategy; the analog control strategy is generated according to the power and frequency response characteristics corresponding to the electrolytic cell group 04;

[0033] When the fluctuation amplitude of the system frequency is greater than a preset threshold, the fluctuation amplitude of the system frequency is reduced by executing the charging and discharging actions of the energy storage device 05 .

[0034] In practical applications, the new energy power source 01 in the embodiment of the present invention may specifically include a wind power device and / or a photovoltaic power generation device, whose power frequency characteristics have the characteristics of a synchronous generator; the load mainly includes an electrolytic cell group, and in addition, it may also include supporting equipment such as motors and control systems.

[0035] In the embodiment of the present invention, the power electronic rectifier 03 can be a semi-controlled type or a fully controlled type, and can provide a DC power supply for the electrolytic cell; the power electronic rectifier 03 implements an analog control strategy according to the power and frequency response characteristics; generally, its power and frequency response characteristics are set to P∞f i ; Among them, i>3, that is, the value of i must be greater than 3.

[0036] Preferably, in the embodiment of the present invention, a more suitable value of i can be obtained according to the following formula, specifically:

[0037]

[0038] Among them, P max is the maximum acceptable power of the electrolytic cell; P min is the acceptable minimum power of the electrolyzer; f max is the maximum value of the system frequency in the preset threshold; f min is the minimum value of the system frequency in the preset threshold.

[0039] In practical applications, the rated frequency of the new energy electrolysis hydrogen production AC island system can be set to 50Hz; the acceptable minimum power of the electrolyzer is set to 40% of the rated power, and the corresponding system frequency is 48Hz; the acceptable maximum power of the electrolyzer is set to 105% of the rated power, and the corresponding system frequency is 51Hz.

[0040] In an embodiment of the present invention, after setting the acceptable minimum power, acceptable maximum power and their corresponding system frequencies of the electrolytic cell, an output power control curve can be further constructed, and then the correspondence between the system frequency fluctuation value and the power floating value of the electrolytic cell group can be determined; in this way, according to the fluctuation amplitude of the system frequency and the output power control curve, the power adjustment amount and adjustment time of the electrolytic cell group can be determined.

[0041] In practical applications, in order to obtain an accurate output power control curve, experiments can be conducted to obtain the corresponding relationships between multiple powers and system frequencies within the range of the minimum acceptable power and the maximum acceptable power.

[0042] In the embodiment of the present invention, the frequency monitoring unit 06 can be used to monitor the system frequency in real time. Then, the control unit 07, as a device with data processing capabilities, can use the system frequency data as a parameter and control the corresponding device according to preset rules to implement different frequency control methods to stabilize the system frequency. Specifically:

[0043] The preset rules in the embodiment of the present invention may specifically include: generating a control signal for the power electronic rectifier 03 according to a preset analog control strategy; the analog control strategy is generated according to the power and frequency response characteristics corresponding to the electrolytic cell group; when the fluctuation amplitude of the system frequency is greater than a preset threshold, reducing the fluctuation amplitude of the system frequency by executing the charging and discharging actions of the electrolytic cell in the energy storage device.

[0044] In the embodiment of the present invention, a simulation control strategy is generated based on the power and frequency response characteristics of the electrolytic cell group 04. In this way, the self-balancing characteristics of the non-electronic power load during short-term frequency fluctuations are simulated through the power control of the power electronic rectifier 03, thereby enabling adaptive regulation based on the fluctuation amplitude in a short period of time. Specifically:

[0045] When the fluctuation amplitude of the system frequency is less than the preset threshold, the power adjustment unit can quickly adjust the power within a reasonable power range acceptable to the electrolytic cell group through the power electronic rectifier 03; in this way, the power adjustment unit can quickly and slightly adjust the system frequency according to the analog control strategy.

[0046] When the fluctuation amplitude of the system frequency is greater than a preset threshold, the controller of the energy storage device 05 performs a corresponding charging and discharging action of the energy storage device 05; the charging and discharging action of the energy storage device 05 is used to reduce the fluctuation amplitude of the system frequency;

[0047] When regulating the system frequency through the charge and discharge control of the energy storage device, the frequency amplitude of the single-step adjustment is large. Therefore, when it is applied to a small-amplitude system disturbance, it is very likely to cause a secondary disturbance to the system frequency, and a good regulation effect cannot be achieved. Therefore, in an embodiment of the present invention, a corresponding limit regulation is set for the regulation method using the charge and discharge of the energy storage device. Only when the fluctuation amplitude of the system frequency is greater than a preset threshold, the charging and discharging action of the energy storage device is used to reduce the fluctuation amplitude of the system frequency.

[0048] In an embodiment of the present invention, when setting the preset threshold, it can be determined based on the capacity of the new energy electrolysis hydrogen production AC island system, the type of generator set, and the power fluctuation tolerance of the electrolyzer group; generally, the preset threshold ±Δf1 can be set according to the ±2.0Hz system frequency.

[0049] To sum up, the new energy electrolysis hydrogen production AC island system in the embodiment of the present invention utilizes the characteristic that its electrolyzer group can accept a wider range of power fluctuations. When a small system frequency disturbance occurs, the power of the electrolyzer group is adjusted by the power electronic rectifier to achieve a rapid response to the system frequency disturbance; specifically, in the embodiment of the present invention, when the fluctuation amplitude of the system frequency is a small disturbance (that is, the fluctuation amplitude is less than the preset threshold), the power of the electrolyzer group is adjusted by the power electronic rectifier to achieve a small adjustment of the system frequency; then, when the fluctuation amplitude of the system frequency is large (that is, the fluctuation amplitude is greater than the preset threshold), the system frequency is stabilized by the charge and discharge control method of the energy storage device.

[0050] As can be seen from the above, the embodiment of the present invention classifies the disturbances. In this way, when subjected to a small disturbance, the power adjustment unit is used to adjust the power of the electrolytic cell group according to the analog control strategy, thereby indirectly adjusting the system frequency. Since the adjustment amplitude of the power of the electrolytic cell group is controllable, the present invention can achieve flexible adjustment of the system frequency through moderate power adjustment. Compared with the charging and discharging control method of the energy storage device, the power adjustment method of the electrolytic cell group in the embodiment of the present invention can avoid the secondary disturbance of the system frequency caused by the charging and discharging action of the energy storage device, thereby achieving a better adjustment effect in the case of a small system disturbance.

[0051] On the other hand, the traditional method of regulating system frequency through charging and discharging control of energy storage devices still has the defect of too long response time; the embodiment of the present invention can achieve millisecond-level response to system disturbances through power electronic rectifiers, and thus can also effectively reduce the negative impact of disturbances on the new energy electrolysis hydrogen production AC island system.

[0052] On the other hand, in the embodiment of the present invention, the system frequency is no longer adjusted by the charge and discharge control of the energy storage device when a small system disturbance occurs. This can significantly reduce the charge and discharge frequency of the energy storage device, thereby effectively increasing the service life of the energy storage device.

[0053] Example 2

[0054] Based on the new energy electrolysis hydrogen production AC island system of embodiment 1, Figure 2 As shown, in an embodiment of the present invention, a frequency control method for a corresponding new energy electrolysis hydrogen production AC island system is also provided, including the steps of:

[0055] S11. Acquire the system frequency of the new energy electrolysis hydrogen production AC island system in real time;

[0056] The frequency stabilization method in the embodiment of the present invention is applicable to a new energy electrolysis hydrogen production AC island system comprising a new energy power supply, an AC power grid, a power electronic rectifier, an electrolyzer group, an energy storage device, a frequency monitoring unit, and a control instruction unit;

[0057] The new energy electrolysis hydrogen production AC island system in the embodiment of the present invention includes an active grid-connected converter type new energy power source, which may specifically include a wind power device and / or a photovoltaic power generation device.

[0058] S12. Using the current system frequency as a parameter, generating a control signal for the power electronic rectifier according to a preset analog control strategy; the analog control strategy is generated according to power and frequency response characteristics corresponding to the electrolytic cell group;

[0059] In practical applications, the frequency monitoring unit can be used to monitor the system frequency of the new energy electrolysis hydrogen production AC island system in real time.

[0060] In the embodiment of the present invention, the power electronic rectifier can be a semi-controlled type or a fully controlled type, and can provide a DC power supply for the electrolytic cell; the power electronic rectifier implements an analog control strategy according to the power and frequency response characteristics; generally, its power and frequency response characteristics are set to P∞f i ; Among them, i>3, that is, the value of i must be greater than 3.

[0061] Preferably, in the embodiment of the present invention, a more suitable value of i can be obtained according to the following formula, specifically:

[0062]

[0063] Among them, P max is the maximum acceptable power of the electrolytic cell; P min is the acceptable minimum power of the electrolyzer; f max is the maximum value of the system frequency in the preset threshold; f min is the minimum value of the system frequency in the preset threshold.

[0064] In practical applications, the rated frequency of the new energy electrolysis hydrogen production AC island system can be set to 50Hz; the acceptable minimum power of the electrolyzer is set to 40% of the rated power, and the corresponding system frequency is 48Hz; the acceptable maximum power of the electrolyzer is set to 105% of the rated power, and the corresponding system frequency is 51Hz.

[0065] In an embodiment of the present invention, after setting the acceptable minimum power and the acceptable maximum power of the electrolytic cell and their corresponding system frequencies, an output power control curve can be further constructed, and then the corresponding relationship between the system frequency fluctuation value and the power floating value of the electrolytic cell group can be determined; in this way, according to the fluctuation amplitude of the system frequency and the output power control curve, the power adjustment amount and adjustment time of the electrolytic cell group can be determined. The specific steps include:

[0066] S21. Pre-generating an output power control curve for the power electronic rectifier, including: assuming that the rated frequency of the new energy electrolysis hydrogen production AC island system is 50 Hz; assuming that the minimum acceptable power of the electrolyzer is 40% of the rated power, and the corresponding minimum system frequency value in the preset threshold is 48 Hz; assuming that the maximum acceptable power of the electrolyzer is 105% of the rated power, and the corresponding maximum system frequency value in the preset threshold is 51 Hz; the output power control curve is used to determine the corresponding relationship between the system frequency fluctuation value and the power floating value of the electrolyzer group;

[0067] S22. Determine the power adjustment amount and adjustment time of the electrolytic cell group according to the fluctuation amplitude of the system frequency and the output power control curve.

[0068] In practical applications, in order to obtain an accurate output power control curve, experiments can be conducted to obtain the corresponding relationships between multiple powers and system frequencies within the range of the minimum acceptable power and the maximum acceptable power.

[0069] In an embodiment of the present invention, when setting the preset threshold, it can be determined based on the capacity of the new energy electrolysis hydrogen production AC island system, the type of generator set, and the power fluctuation tolerance of the electrolyzer group; generally, the preset threshold ±Δf1 can be set according to the ±2.0Hz system frequency.

[0070] In the embodiment of the present invention, the frequency monitoring unit can be used to monitor the system frequency in real time. Then, the control unit, as a device with data processing capabilities, can use the system frequency data as a parameter and control the corresponding device according to preset rules to implement different frequency control methods to stabilize the system frequency. Specifically:

[0071] The preset rules in the embodiment of the present invention may specifically include: generating a control signal for the power electronic rectifier according to a preset analog control strategy; the analog control strategy is generated according to the power and frequency response characteristics corresponding to the electrolytic cell group; when the fluctuation amplitude of the system frequency is greater than a preset threshold, reducing the fluctuation amplitude of the system frequency by executing the charging and discharging actions of the electrolytic cell in the energy storage device.

[0072] In an embodiment of the present invention, a simulation control strategy is generated based on the power and frequency response characteristics of the electrolytic cell group. In this way, the self-balancing characteristics of the non-electronic power load during short-term frequency fluctuations are simulated through the power control of the power electronic rectifier, thereby enabling adaptive regulation based on the fluctuation amplitude in a short period of time. Specifically:

[0073] When the fluctuation amplitude of the system frequency is less than the preset threshold, the power adjustment unit can quickly adjust the power within a reasonable power range acceptable to the electrolytic cell group through the power electronic rectifier; in this way, the power adjustment unit can quickly and slightly adjust the system frequency according to the analog control strategy.

[0074] S13. When the fluctuation amplitude of the system frequency is greater than a preset threshold, the fluctuation amplitude of the system frequency is reduced by executing charging and discharging actions of the electrolytic cell in the energy storage device.

[0075] When the fluctuation amplitude of the system frequency is greater than a preset threshold, the controller of the energy storage device performs a corresponding charging and discharging action of the energy storage device; the charging and discharging action of the energy storage device is used to reduce the fluctuation amplitude of the system frequency;

[0076] When regulating the system frequency through the charge and discharge control of the energy storage device, the frequency amplitude of the single-step adjustment is large. Therefore, when it is applied to a small-amplitude system disturbance, it is very likely to cause a secondary disturbance to the system frequency, and a good regulation effect cannot be achieved. Therefore, in an embodiment of the present invention, a corresponding limit regulation is set for the regulation method using the charge and discharge of the energy storage device. Only when the fluctuation amplitude of the system frequency is greater than a preset threshold, the charging and discharging action of the energy storage device is used to reduce the fluctuation amplitude of the system frequency.

[0077] To sum up, the new energy electrolysis hydrogen production AC island system in the embodiment of the present invention utilizes the characteristic that its electrolyzer group can accept a wider range of power fluctuations. When a small system frequency disturbance occurs, the power of the electrolyzer group is adjusted by the power electronic rectifier to achieve a rapid response to the system frequency disturbance; specifically, in the embodiment of the present invention, when the fluctuation amplitude of the system frequency is a small disturbance (that is, the fluctuation amplitude is less than the preset threshold), the power of the electrolyzer group is adjusted by the power electronic rectifier to achieve a small adjustment of the system frequency; then, when the fluctuation amplitude of the system frequency is large (that is, the fluctuation amplitude is greater than the preset threshold), the system frequency is stabilized by the charge and discharge control method of the energy storage device.

[0078] As can be seen from the above, the embodiment of the present invention classifies the disturbances. In this way, when subjected to a small disturbance, the power adjustment unit is used to adjust the power of the electrolytic cell group according to the analog control strategy, thereby indirectly adjusting the system frequency. Since the adjustment amplitude of the power of the electrolytic cell group is controllable, the present invention can achieve flexible adjustment of the system frequency through moderate power adjustment. Compared with the charging and discharging control method of the energy storage device, the power adjustment method of the electrolytic cell group in the embodiment of the present invention can avoid the secondary disturbance of the system frequency caused by the charging and discharging action of the energy storage device, thereby achieving a better adjustment effect in the case of a small system disturbance.

[0079] On the other hand, the traditional method of regulating system frequency through charging and discharging control of energy storage devices still has the defect of too long response time; the embodiment of the present invention can achieve millisecond-level response to system disturbances through power electronic rectifiers, and thus can also effectively reduce the negative impact of disturbances on the new energy electrolysis hydrogen production AC island system.

[0080] On the other hand, in the embodiment of the present invention, the system frequency is no longer adjusted by the charge and discharge control of the energy storage device when a small system disturbance occurs. This can significantly reduce the charge and discharge frequency of the energy storage device, thereby effectively increasing the service life of the energy storage device.

[0081] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A new energy electrolysis hydrogen production AC island system, characterized by: It includes a new energy power source, an AC power grid, a power electronic rectifier, an electrolyzer group, an energy storage device, a frequency monitoring unit and a control unit; The control unit uses the system frequency data collected by the frequency monitoring unit as a parameter and generates a corresponding control signal according to a preset rule; The preset rules include: generating a control signal for the power electronic rectifier according to a preset analog control strategy; wherein the analog control strategy is generated according to power and frequency response characteristics corresponding to the electrolytic cell group; When the fluctuation amplitude of the system frequency is greater than a preset threshold, the fluctuation amplitude of the system frequency is reduced by executing the charging and discharging actions of the energy storage device.

2. The new energy electrolysis hydrogen production AC island system according to claim 1 is characterized in that: The new energy power source includes a wind power device and / or a photovoltaic power generation device.

3. The new energy electrolysis hydrogen production AC island system according to claim 2 is characterized in that: The electrolytic cell group includes a plurality of electrolytic cells.

4. The new energy electrolysis hydrogen production AC island system according to claim 3 is characterized in that: The preset threshold ±Δf1 includes ±2.0 Hz.

5. The new energy electrolysis hydrogen production AC island system according to claim 5 is characterized in that: The analog control strategy of the power electronic rectifier includes: The power and frequency response characteristics are set as P∞f i ; where i>3.

6. The new energy electrolysis hydrogen production AC island system according to claim 5 is characterized in that: The simulation control strategy includes: The output power control curve of the power electronic rectifier includes: assuming that the rated frequency of the new energy electrolysis hydrogen production AC island system is 50Hz; assuming that the acceptable minimum power of the electrolyzer is 40% of the rated power, and the corresponding system frequency is 48Hz; the acceptable maximum power of the electrolyzer is 105% of the rated power, and the corresponding system frequency is 51Hz; the output power control curve is used to determine the correspondence between the system frequency fluctuation value and the power floating value of the electrolyzer group; according to the fluctuation amplitude of the system frequency and the output power control curve, the power adjustment amount and adjustment time of the electrolyzer group can be determined.

7. The new energy electrolysis hydrogen production AC island system according to claim 5 is characterized in that: The P∞f i ,include: Among them, P max is the maximum acceptable power of the electrolytic cell; P min is the acceptable minimum power of the electrolyzer; f max is the maximum value of the system frequency in the preset threshold; f min is the minimum value of the system frequency in the preset threshold.

8. A frequency control method for an AC island system for hydrogen production by electrolysis from a new energy source, the AC island system comprising a new energy power source, an AC power grid, a power electronic rectifier, an electrolytic cell group, an energy storage device, a frequency monitoring unit, and a control instruction unit, characterized in that: Including steps: S11. Acquire the system frequency of the new energy electrolysis hydrogen production AC island system in real time; S12. Using the current system frequency as a parameter, generating a control signal for the power electronic rectifier according to a preset analog control strategy; the analog control strategy is generated according to power and frequency response characteristics corresponding to the electrolytic cell group; S13. When the fluctuation amplitude of the system frequency is greater than a preset threshold, reducing the fluctuation amplitude of the system frequency by executing charging and discharging actions of the energy storage device.

9. The frequency control method of the AC island system for hydrogen production by electrolysis of new energy according to claim 8 is characterized in that: The new energy power source includes a wind power device and / or a photovoltaic power generation device, and its power frequency characteristics have synchronous generator characteristics.

10. The frequency control method of the AC island system for hydrogen production by electrolysis of new energy according to claim 9 is characterized in that: The preset threshold ±Δf1 includes ±2.0 Hz.

11. The frequency control method of the AC island system for hydrogen production by electrolysis of new energy according to claim 10, characterized in that: The simulation control strategy includes: The power and frequency response characteristics are set as P∞f i ; The value range of i includes: i>3.

12. The frequency control method of the AC island system for hydrogen production by electrolysis of new energy according to claim 11, characterized in that: The simulation control strategy includes: S21. Pre-generating an output power control curve for the power electronic rectifier, including: assuming that the rated frequency of the new energy electrolysis hydrogen production AC island system is 50 Hz; assuming that the minimum acceptable power of the electrolyzer is 40% of the rated power, and the corresponding minimum system frequency value in the preset threshold is 48 Hz; assuming that the maximum acceptable power of the electrolyzer is 105% of the rated power, and the corresponding maximum system frequency value in the preset threshold is 51 Hz; the output power control curve is used to determine the corresponding relationship between the system frequency fluctuation value and the power floating value of the electrolyzer group; S22. Determine the power adjustment amount and adjustment time of the electrolytic cell group according to the fluctuation amplitude of the system frequency and the output power control curve.

13. The frequency control method of the AC island system for hydrogen production by electrolysis of new energy according to claim 12, characterized in that: P∞f i ,include: Among them, P max is the maximum acceptable power of the electrolytic cell; P min is the acceptable minimum power of the electrolyzer; f max is the maximum value of the system frequency in the preset threshold; f min is the minimum value of the system frequency in the preset threshold.

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