A fluctuating power water electrolysis hydrogen production system and a control method thereof

Abstract

The application discloses a fluctuating power water electrolysis hydrogen production system and a control method thereof, and the fluctuating power water electrolysis hydrogen production system comprises an electrolytic cell, a hydrogen gas-liquid separator, a controller, a first temperature measuring point T1, a second temperature measuring point T2, a first pressure measuring point P1 and a second pressure measuring point P2; wherein the first temperature measuring point T1 is located upstream of the electrolytic cell, and the second temperature measuring point T2 is located downstream of the electrolytic cell; the first pressure measuring point P1 is located between the electrolytic cell and the hydrogen gas-liquid separator, and the second pressure measuring point P2 is located between the hydrogen gas-liquid separator and an outlet valve. The application sets two temperature feedback control points upstream and downstream of the electrolytic cell and sets two pressure control points upstream and downstream of the gas-liquid separator, so as to solve the problem that the controller is not timely and accurate in control due to pressure hysteresis and temperature hysteresis, and thus the influence of fluctuating working conditions is offset.

Description

Technical Field

[0001] This invention relates to the fields of hydrogen energy, water electrolysis systems, and electrochemical testing, specifically to a fluctuating power water electrolysis hydrogen production control system and its control method. Background Technology

[0002] In the field of hydrogen energy, there are several methods for producing hydrogen, including water electrolysis, methanol reforming, and natural gas reforming. Each of these methods has its own advantages and disadvantages. Methanol-based hydrogen production requires post-processing purification and produces carbon-containing gases as byproducts. Natural gas-based hydrogen production is similar to methanol-based hydrogen production. Among these methods, water electrolysis is a green energy method with greater advantages.

[0003] Currently, water electrolysis hydrogen production systems are developing towards large-scale plants, with most engineering projects having a single unit capacity of MW or more. Water electrolysis methods are mainly divided into alkaline and proton exchange membrane (PEM) electrolysis. The difference between these two methods lies in the different membrane materials used in PEM and alkaline systems, resulting in different performance characteristics. Alkaline systems have lower costs but lower efficiency, while PEM systems have higher costs, higher efficiency, and better resistance to fluctuations.

[0004] The existing water electrolysis hydrogen production systems have the following problems: They are unsuitable for power plant peak shaving and valley filling conditions. Under variable load conditions, power fluctuates, and the system's response is slow, resulting in temperature hysteresis before and after the electrolyzer. Furthermore, the internal liquid level of the gas-liquid separator experiences delays and imbalances, leading to pressure hysteresis before and after the separator. If only a single temperature and pressure point is used for control, the controller struggles to provide timely and accurate control. Improving the control method to offset these temperature and pressure hysteresis becomes complex. These issues result in a relatively narrow power adjustment range for existing water electrolysis hydrogen production systems. PEM equipment has a wider power adjustment range than alkaline systems, typically adjustable from 5-115% of the existing full load, while domestically produced alkaline electrolyzer hydrogen production equipment typically has a power fluctuation range adjustable from 20-110% of the existing full load.

[0005] Therefore, how to further broaden the power adjustment range of the water electrolysis hydrogen production system to make it suitable for fluctuating operating conditions is a concern.

[0006] To address the above problems, this invention is proposed. Summary of the Invention

[0007] This invention aims to overcome the shortcomings of existing technologies. Addressing the issues of limited power adjustment range and unsuitability for drastically fluctuating operating conditions in water electrolysis hydrogen production systems, this invention establishes two pressure feedback control points (a first pressure measurement point P1 and a second pressure measurement point P2) and two temperature feedback control points (a first temperature measurement point T1 and a second temperature measurement point T2). By calculating the magnitude and difference between the first pressure measurement point P1 and the second pressure measurement point P2, the pressure of the system is controlled. Then, the temperature feedback control point is selected based on the power used by the water electrolysis hydrogen production equipment and the amplitude of power fluctuations, thereby offsetting the effects of untimely and inaccurate controller control caused by pressure and temperature hysteresis.

[0008] The technical solution adopted in this invention is as follows:

[0009] The first aspect of the present invention provides a fluctuating power water electrolysis hydrogen production system, which includes an electrolyzer, a hydrogen gas-liquid separator, a controller, a first temperature measuring point T1, a second temperature measuring point T2, a first pressure measuring point P1, and a second pressure measuring point P2.

[0010] The hydrogen components produced by water electrolysis in the electrolytic cell enter the hydrogen gas-liquid separator for gas-liquid separation. The separated hydrogen is discharged and collected through the hydrogen outlet pipeline, which is equipped with an outlet valve.

[0011] Wherein, the first temperature measuring point T1 is located upstream of the electrolytic cell, and the second temperature measuring point T2 is located downstream of the electrolytic cell;

[0012] The first pressure measuring point P1 is located between the electrolytic cell and the hydrogen gas-liquid separator, and the second pressure measuring point P2 is located between the hydrogen gas-liquid separator and the outlet valve;

[0013] The temperature feedback control point of the controller switches between the first temperature measurement point T1 and the second temperature measurement point T2.

[0014] The pressure feedback control points of the controller include the first pressure measurement point P1 and the second pressure measurement point P2.

[0015] Preferably, the controller controls the pressure of the water electrolysis hydrogen production system by controlling the opening and closing degree of the outlet valve.

[0016] Preferably, the water obtained after separation by the hydrogen gas-liquid separator is returned to the electrolyzer for further electrolysis.

[0017] Preferably, the fluctuating power water electrolysis hydrogen production system also includes an oxygen gas-liquid separator;

[0018] The oxygen component produced after water electrolysis in the electrolytic cell enters the oxygen gas-liquid separator for gas-liquid separation. The oxygen obtained after separation is collected, and the water obtained after separation is returned to the electrolytic cell for further electrolysis.

[0019] Preferably, the fluctuating power water electrolysis hydrogen production system also includes a chiller unit;

[0020] The cooling water of the chiller unit is used to cool the hydrogen gas-liquid separator and the oxygen gas-liquid separator.

[0021] Preferably, the fluctuating power water electrolysis hydrogen production system further includes a pump, through which the water to be electrolyzed is transported to the electrolyzer.

[0022] Preferably, the power adjustment range of the fluctuating power water electrolysis hydrogen production system is 0-150% of full load.

[0023] The second aspect of the present invention provides a control method for the fluctuating power water electrolysis hydrogen production system described in the first aspect of the present invention. When encountering power fluctuations, pressure control is performed first, and temperature control is performed after the pressure stabilizes.

[0024] The pressure control is as follows: the controller uses the first pressure measurement point P1 and the second pressure measurement point P2 as pressure feedback control points, and determines the degree of opening and closing of the outlet valve to control the pressure of the water electrolysis hydrogen production system by calculating the magnitude and difference between the first pressure measurement point P1 and the second pressure measurement point P2.

[0025] The temperature control is as follows: the controller switches the temperature feedback control point between the first temperature measurement point T1 and the second temperature measurement point T2 based on the power used by the water electrolysis hydrogen production equipment and the power fluctuation range.

[0026] Preferably, the pressure control is as follows: when the second pressure measuring point P2 is greater than the first pressure measuring point P1, and the difference between the first pressure measuring point P1 and the second pressure measuring point P2 is greater than 0.1 MPa, the controller controls the opening of the outlet valve to increase;

[0027] When the second pressure measurement point P2 is less than the first pressure measurement point P1, and the difference between the first pressure measurement point P1 and the second pressure measurement point P2 is greater than 0.1 MPa, the controller controls the opening of the outlet valve to decrease.

[0028] When the difference between the first pressure measuring point P1 and the second pressure measuring point P2 is less than or equal to 0.1 MPa, the opening of the outlet valve is not adjusted and remains stable for 1-3 minutes, which is considered as pressure stability.

[0029] The temperature control is as follows: when the water electrolysis hydrogen production equipment is used in the power range of 0-1MW, the controller uses the first temperature measurement point T1 as the temperature feedback control point.

[0030] When the water electrolysis hydrogen production equipment is used in the power range of 1-5MW and the power fluctuation is less than 50KW / S, the controller uses the second temperature measurement point T2 as the temperature feedback control point.

[0031] When the water electrolysis hydrogen production equipment is used in the power range of 1-5MW and the power fluctuation range is greater than or equal to 50KW / S, the controller uses the first temperature measurement point T1 as the temperature feedback control point.

[0032] Preferably, when the water electrolysis hydrogen production equipment is used in the 0-1MW power range, the temperature feedback control point is selected by calculating the cumulative time within this power range. When the calculated cumulative time at this low power is within the normal range (3-5 hours, depending on the design time), the controller uses the first temperature measurement point T1 as the temperature feedback control point. However, when the calculated cumulative time at this low power exceeds the normal range, the controller uses the second temperature measurement point T2 as the temperature feedback control point. This is a further preferred embodiment of the invention, that is, when the water electrolysis hydrogen production equipment is used in the 0-1MW power range, the controller can use the first temperature measurement point T1 as the temperature feedback control point; or more preferably, the temperature feedback control point is selected by calculating the cumulative time within this power range.

[0033] This invention comprises two parts: pressure control and temperature control. When the fluctuating power water electrolysis hydrogen production system operates at atmospheric pressure, pressure control is not required. However, when the pressure reaches high pressure (1-5 MPa), pressure hysteresis occurs. In other words, under fluctuating operating conditions, both temperature and pressure hysteresis exist, necessitating the consideration of both pressure and temperature control. For PEM-type water electrolysis hydrogen production systems, since the hydrogen side may experience high pressure while the oxygen side is typically at atmospheric pressure, this invention sets pressure measurement points upstream and downstream of the hydrogen-side gas-liquid separator. For alkaline-type water electrolysis hydrogen production systems, since high pressure may also exist on the oxygen side, for safety reasons, a pressure measurement point and outlet valve can be installed downstream of the oxygen gas-liquid separator. However, pressure control can still be achieved using the method described in this invention.

[0034] In this invention, the temperature point before the stack is the first temperature measurement point T1 located upstream of the electrolytic cell, and the temperature point after the stack is the second temperature measurement point T2 located downstream of the electrolytic cell.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. Existing technologies typically use a fixed post-stacking temperature as the temperature feedback point. The problem is that when faced with instantaneous power changes, such as a sudden increase in power, the temperature hysteresis at the post-stacking temperature is too large. If this temperature point is used as the temperature feedback point, the response speed is too slow. By the time the temperature is transmitted to the controller, that portion of power has already been wasted, and the controller has not provided timely control. Correspondingly, currently, there is usually only one pressure measurement point, located between the hydrogen gas-liquid separator and the outlet valve. When the power changes, the hydrogen production of the electrolyzer also changes, so there is also pressure hysteresis upstream and downstream of the gas-liquid separator. If the system pressure is controlled solely by the pressure measurement point downstream of the hydrogen gas-liquid separator, there are problems with untimely and inaccurate control. To address the problem of fluctuating operating conditions, some researchers are currently adjusting the fluctuating operating conditions by increasing the flow rate (to accommodate power increases) or predicting power in advance. This invention overcomes the previous technical biases of using a fixed post-stacking temperature as the temperature feedback point and the downstream pressure of the gas-liquid separator as the pressure feedback point. Instead, it sets two temperature feedback control points, a first temperature measurement point T1 and a second temperature measurement point T2, and two pressure control points, a first pressure measurement point P1 and a second pressure measurement point P2. By setting two temperature feedback control points upstream and downstream of the electrolyzer and two pressure control points upstream and downstream of the hydrogen gas-liquid separator, the problem of untimely and inaccurate controller control caused by pressure hysteresis and temperature hysteresis is solved, thereby offsetting the impact of fluctuating operating conditions.

[0037] 2. This invention sets two temperature feedback control points: a first temperature measurement point T1 and a second temperature measurement point T2. The temperature feedback control point is selected based on the power used by the water electrolysis hydrogen production equipment and the power fluctuation range. Furthermore, this invention sets two pressure feedback control points: a first pressure measurement point P1 and a second pressure measurement point P2. By calculating the magnitude and difference between the first pressure measurement point P1 and the second pressure measurement point P2, the opening and closing degree of the outlet valve is determined to control the pressure of the water electrolysis hydrogen production system, thereby offsetting the effects of pressure hysteresis and temperature hysteresis. The water electrolysis hydrogen production system of this invention is suitable for fluctuating power conditions, and its power adjustment range is 0-150% of full load.

[0038] 3. This invention employs multiple temperature and pressure control points for feedback control, utilizing a controller for simple, convenient, and low-cost operation. Using this method to control a water electrolysis hydrogen production system can reduce the impact of power fluctuations, improving overall system efficiency. Furthermore, this method only requires setting multiple temperature and pressure control feedback points on the water electrolysis hydrogen production system, minimizing system modifications and demonstrating strong practical value.

[0039] 4. The temperature feedback control point is selected based on the power output and fluctuation range of the water electrolysis hydrogen production equipment. The in-pile temperature has virtually no temperature hysteresis and its temperature response speed is faster than that of the post-pile temperature. Therefore, it is selected for low load or fluctuating conditions. Using the in-pile temperature as the control point allows for a faster controller response. Once the unit is running stably under high load, the post-pile temperature is used as the control point. By switching the control point, the controller can be used for simple, convenient, and low-cost control, thereby improving the overall efficiency of the unit.

[0040] 5. The present invention also selects the temperature feedback control point by calculating the cumulative time in the low power range. When the calculated cumulative time in the low power range is within the normal range (3-5 hours, depending on the design time), the controller uses the first temperature measurement point T1 as the temperature feedback control point. However, when the calculated cumulative time in the low power range exceeds the normal range, the controller uses the second temperature measurement point T2 as the temperature feedback control point.

[0041] 6. The control device and control method of the present invention are not affected by the membrane material, so the test method is not limited by the type of electrolysis and is applicable to alkaline, PEM, AEM and other electrolysis fields, with a wide range of applications. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the fluctuating power water electrolysis hydrogen production system of the present invention.

[0043] Figure 2 This is a flowchart of the temperature control method for the fluctuating power water electrolysis hydrogen production system of the present invention. Detailed Implementation

[0044] The present invention will be further described below through embodiments, but is not limited to these embodiments. Experimental methods not specifically described in the embodiments generally use conventional conditions and conditions described in manuals, or conditions recommended by the manufacturer. The general equipment, materials, reagents, etc., used are all commercially available unless otherwise specified.

[0045] Example 1

[0046] This embodiment provides a more detailed description of the fluctuating power water electrolysis hydrogen production system and the fluctuating power water electrolysis hydrogen production temperature control method.

[0047] See Figure 1 The fluctuating power water electrolysis hydrogen production system includes an electrolyzer, a hydrogen gas-liquid separator, a controller, a first temperature measurement point T1, a second temperature measurement point T2, a first pressure measurement point P1, and a second pressure measurement point P2.

[0048] The hydrogen components produced by water electrolysis in the electrolytic cell enter the hydrogen gas-liquid separator for gas-liquid separation. The separated hydrogen is discharged and collected through the hydrogen outlet pipeline, which is equipped with an outlet valve.

[0049] Wherein, the first temperature measuring point T1 is located upstream of the electrolytic cell, and the second temperature measuring point T2 is located downstream of the electrolytic cell;

[0050] The first pressure measuring point P1 is located between the electrolytic cell and the hydrogen gas-liquid separator, and the second pressure measuring point P2 is located between the hydrogen gas-liquid separator and the outlet valve;

[0051] The temperature feedback control point of the controller switches between the first temperature measurement point T1 and the second temperature measurement point T2.

[0052] The pressure feedback control points of the controller include the first pressure measurement point P1 and the second pressure measurement point P2.

[0053] The controller controls the pressure of the water electrolysis hydrogen production system by controlling the opening and closing degree of the outlet valve.

[0054] The water obtained after separation by the hydrogen gas-liquid separator is returned to the electrolytic cell for further electrolysis.

[0055] The power adjustment range of the fluctuating power water electrolysis hydrogen production system is 0-150% of full load.

[0056] The fluctuating power water electrolysis hydrogen production system also includes an oxygen gas-liquid separator; the oxygen components produced after water electrolysis in the electrolyzer enter the oxygen gas-liquid separator for gas-liquid separation, the oxygen obtained after separation is collected, and the water obtained after separation is returned to the electrolyzer for further electrolysis.

[0057] The fluctuating power water electrolysis hydrogen production system also includes a chiller unit; the cooling water of the chiller unit is used to cool the hydrogen gas-liquid separator and the oxygen gas-liquid separator.

[0058] The fluctuating power water electrolysis hydrogen production system also includes a pump, through which the water to be electrolyzed is transported to the electrolyzer.

[0059] In actual use, the overall control strategy of the above-mentioned fluctuating power water electrolysis hydrogen production system is to first control the pressure when encountering power fluctuations, and then control the temperature after the pressure stabilizes.

[0060] Pressure control section:

[0061] When the pressure of the fluctuating power water electrolysis hydrogen production system is at atmospheric pressure, no consideration is needed. When the pressure of the fluctuating power water electrolysis hydrogen production system is at high pressure (1-5 MPa), pressure control is considered. During initial operation, pressure is generally first held up by closing the outlet valve. Once the second pressure measurement point P2 reaches the target value, the outlet valve is opened. At this time, the pressure at the first pressure measurement point P1 is higher than that at the second pressure measurement point P2. At this time, the hydrogen gas-liquid separator functions as a buffer tank.

[0062] After the above process is completed, during the operation of the fluctuating power water electrolysis hydrogen production system, the pressure control is as follows: The controller uses the first pressure measurement point P1 and the second pressure measurement point P2 as pressure feedback control points. By calculating the magnitude and difference between the first pressure measurement point P1 and the second pressure measurement point P2, the controller determines the opening degree of the outlet valve to control the pressure of the water electrolysis hydrogen production system. Specifically, when the second pressure measurement point P2 is greater than the first pressure measurement point P1, and the difference between the first pressure measurement point P1 and the second pressure measurement point P2 is greater than 0.1 MPa, the controller controls the opening degree of the outlet valve to increase; when the second pressure measurement point P2 is less than the first pressure measurement point P1, and the difference between the first pressure measurement point P1 and the second pressure measurement point P2 is greater than 0.1 MPa, the controller controls the opening degree of the outlet valve to decrease; when the difference between the first pressure measurement point P1 and the second pressure measurement point P2 is less than or equal to 0.1 MPa, the opening degree of the outlet valve is not adjusted and remains stable for 1-3 minutes. After the pressure stabilizes, temperature control is then implemented.

[0063] Temperature control section:

[0064] The controller switches the temperature feedback control point between the first temperature measurement point T1 and the second temperature measurement point T2 based on the power used by the water electrolysis hydrogen production equipment and the power fluctuation range. Specifically, when the water electrolysis hydrogen production equipment is used in the power range of 0-1MW, the controller uses the first temperature measurement point T1 as the temperature feedback control point; when the water electrolysis hydrogen production equipment is used in the power range of 1-5MW and the power fluctuation range is less than 50kW / s, the controller uses the second temperature measurement point T2 as the temperature feedback control point; when the water electrolysis hydrogen production equipment is used in the power range of 1-5MW and the power fluctuation range is greater than or equal to 50kW / s, the controller uses the first temperature measurement point T1 as the temperature feedback control point.

[0065] Furthermore, when the water electrolysis hydrogen production equipment is used in the 0-1MW power range, the temperature feedback control point is selected by calculating the cumulative time in this power range; when the calculated cumulative time in this low power range is within the normal range, the controller uses the first temperature measurement point T1 as the temperature feedback control point, but when the calculated cumulative time in this low power range exceeds the normal range, the controller uses the second temperature measurement point T2 as the temperature feedback control point.

[0066] During stable operation of the water electrolysis hydrogen production equipment, the temperature feedback control point can be selected according to the above method. However, the water electrolysis hydrogen production system also has several special situations: during the process from start-up to normal operation, during shutdown, and during temporary start-up after shutdown. In these cases, the control method for the fluctuating power water electrolysis hydrogen production system is as follows (see below). Figure 2 :

[0067] During the process from startup to normal operation, the electrolyte temperature rises in about 0.5-1.5 hours. The temperature fluctuates greatly during the heating process. When the temperature after the reactor is ≤75℃, the temperature before the reactor is used as the control point to delay the temperature hysteresis. When the temperature after the reactor is >75℃, the temperature after the reactor is used as the control point until the temperature after the reactor stabilizes at about 90-95℃.

[0068] During the operation of the whole machine, after inputting the operating power according to the above figure, calculate whether this power is within the low load range of the device. If not, directly select the second temperature measurement point T2 as the temperature feedback control point. If so, calculate the time at this power. If the time exceeds the normal range, select the second temperature measurement point T2 as the temperature feedback control point. If the time is within the normal range, select the first temperature measurement point T1 as the temperature feedback control point.

[0069] When selecting the second temperature measurement point T2 as the temperature feedback control point, if the power fluctuation reaches 50kw / s over a certain period of time, the first temperature measurement point T1 will be switched to the temperature feedback control point. If the power fluctuation does not reach 50kw / s over a certain period of time, the second temperature measurement point T2 will still be selected as the temperature feedback control point.

[0070] During the shutdown process, the time required is longer, generally 3-6 hours or even longer, and the temperature delay is relatively large. During this process, the in-core temperature is used as the control point throughout.

[0071] If the unit is temporarily started during shutdown, the back-end temperature must be determined. If the back-end temperature is below 65°C, the unit should be controlled by the front-end temperature. When the back-end temperature rises to 75°C, the unit should be controlled by the back-end temperature. If the back-end temperature is above 65°C, the unit should be controlled directly by the back-end temperature.

[0072] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. A control method for a fluctuating power water electrolysis hydrogen production system, characterized in that, The fluctuating power water electrolysis hydrogen production system includes an electrolyzer, a hydrogen gas-liquid separator, a controller, a first temperature measurement point T1, a second temperature measurement point T2, a first pressure measurement point P1, and a second pressure measurement point P2. The hydrogen components produced by water electrolysis in the electrolytic cell enter the hydrogen gas-liquid separator for gas-liquid separation. The separated hydrogen is discharged and collected through the hydrogen outlet pipeline, which is equipped with an outlet valve. Wherein, the first temperature measuring point T1 is located upstream of the electrolytic cell, and the second temperature measuring point T2 is located downstream of the electrolytic cell; The first pressure measuring point P1 is located between the electrolytic cell and the hydrogen gas-liquid separator, and the second pressure measuring point P2 is located between the hydrogen gas-liquid separator and the outlet valve; The temperature feedback control point of the controller switches between the first temperature measurement point T1 and the second temperature measurement point T2. The pressure feedback control points of the controller include the first pressure measurement point P1 and the second pressure measurement point P2; The control method for the fluctuating power water electrolysis hydrogen production system involves first controlling the pressure when encountering power fluctuations, and then controlling the temperature after the pressure stabilizes. The pressure control is as follows: the controller uses the first pressure measurement point P1 and the second pressure measurement point P2 as pressure feedback control points, and determines the degree of opening and closing of the outlet valve to control the pressure of the water electrolysis hydrogen production system by calculating the magnitude and difference between the first pressure measurement point P1 and the second pressure measurement point P2. When the second pressure measurement point P2 is greater than the first pressure measurement point P1, and the difference between the first pressure measurement point P1 and the second pressure measurement point P2 is greater than 0.1 MPa, the controller controls the outlet valve to increase its opening. When the second pressure measurement point P2 is less than the first pressure measurement point P1, and the difference between the first pressure measurement point P1 and the second pressure measurement point P2 is greater than 0.1 MPa, the controller controls the opening of the outlet valve to decrease. When the difference between the first pressure measuring point P1 and the second pressure measuring point P2 is less than or equal to 0.1 MPa, the opening of the outlet valve is not adjusted and remains stable for 1-3 minutes. The temperature control is as follows: the controller switches the temperature feedback control point between the first temperature measurement point T1 and the second temperature measurement point T2 based on the power used by the water electrolysis hydrogen production equipment and the power fluctuation range. When the water electrolysis hydrogen production equipment is used in the power range of 0-1MW, the controller uses the first temperature measurement point T1 as the temperature feedback control point. When the water electrolysis hydrogen production equipment is used in the power range of 1-5MW and the power fluctuation is less than 50kW / s, the controller uses the second temperature measurement point T2 as the temperature feedback control point. When the water electrolysis hydrogen production equipment is used in the power range of 1-5MW and the power fluctuation range is greater than or equal to 50kW / s, the controller uses the first temperature measurement point T1 as the temperature feedback control point.

2. The control method according to claim 1, characterized in that, The controller controls the pressure of the water electrolysis hydrogen production system by controlling the opening and closing degree of the outlet valve.

3. The control method according to claim 1, characterized in that, The water obtained after separation by the hydrogen gas-liquid separator is returned to the electrolytic cell for further electrolysis.

4. The control method according to claim 1, characterized in that, It also includes an oxygen gas-liquid separator; The oxygen component produced after water electrolysis in the electrolytic cell enters the oxygen gas-liquid separator for gas-liquid separation. The oxygen obtained after separation is collected, and the water obtained after separation is returned to the electrolytic cell for further electrolysis.

5. The control method according to claim 4, characterized in that, It also includes chiller units; The cooling water of the chiller unit is used to cool the hydrogen gas-liquid separator and the oxygen gas-liquid separator.

6. The control method according to claim 1, characterized in that, It also includes a pump through which the water to be electrolyzed is transported to the electrolytic cell.

7. The control method according to claim 1, characterized in that, The power adjustment range of the fluctuating power water electrolysis hydrogen production system is 0-150% of full load.

8. The control method according to claim 1, characterized in that, When the water electrolysis hydrogen production equipment is used in the power range of 0-1MW, the temperature feedback control point is selected by calculating the cumulative time in this power range; When the cumulative time of the calculated low power is within the normal range, the controller uses the first temperature measurement point T1 as the temperature feedback control point; however, when the cumulative time of the calculated low power exceeds the normal range, the controller uses the second temperature measurement point T2 as the temperature feedback control point.

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