Electrolytic cell impedance detection method, device and water electrolysis hydrogen production device

Abstract

The present disclosure relates to an electrolytic tank impedance detection method and device and a water electrolysis hydrogen production device. The electrolytic tank is applied to a water electrolysis hydrogen production device, and the water electrolysis hydrogen production device comprises the electrolytic tank and a hydrogen production power supply, and the hydrogen production power supply comprises a reactor. The method comprises: detecting a first voltage across the electrolytic tank and a first current output by the hydrogen production power supply when controlling the water electrolysis hydrogen production device to operate; injecting an alternating current signal of a predetermined frequency into the current of the reactor, and detecting a second voltage across the electrolytic tank and a second current output by the hydrogen production power supply; and determining the impedance of the electrolytic tank according to the first voltage, the first current, the second voltage and the second current. In this way, the influence of the inductive impedance of the reactor on the detection result of the impedance of the electrolytic tank can be reduced, the calculated impedance of the electrolytic tank is more accurate, and a reliable basis for the maintenance of the electrolytic tank is provided.

Description

Technical Field

[0001] This disclosure relates to the field of electrolysis technology, specifically to an electrolyzer impedance detection method, apparatus, and water electrolysis hydrogen production apparatus. Background Technology

[0002] Electrolyzers are the core equipment for converting electrical energy into hydrogen energy. The impedance of an electrolyzer can, to some extent, reflect its internal state and lifespan. Typically, as phenomena such as gas blockage, decreased catalyst activity, or coating peeling occur inside the electrolyzer, its corresponding impedance value increases. Therefore, monitoring the impedance of the electrolyzer is of great significance for its maintenance. However, current methods for detecting electrolyzer impedance are relatively crude and the results are not accurate. Summary of the Invention

[0003] The purpose of this disclosure is to provide a method, apparatus, and water electrolysis hydrogen production apparatus that provide relatively accurate and reliable electrolyzer impedance detection results.

[0004] To achieve the above objectives, this disclosure provides a method for detecting the impedance of an electrolyzer, wherein the electrolyzer is used in a water electrolysis hydrogen production device, the water electrolysis hydrogen production device includes the electrolyzer and a hydrogen production power supply, the hydrogen production power supply includes a reactor, and the method includes:

[0005] When controlling the operation of the water electrolysis hydrogen production device, the first voltage across the electrolyzer and the first current output by the hydrogen production power supply are detected.

[0006] An AC signal of a predetermined frequency is injected into the current of the reactor, and the second voltage across the electrolyzer and the second current output by the hydrogen production power supply are detected.

[0007] The impedance of the electrolytic cell is determined based on the first voltage, the first current, the second voltage, and the second current.

[0008] Optionally, determining the impedance of the electrolytic cell based on the first voltage, the first current, the second voltage, and the second current includes:

[0009] A third voltage, which increases across the electrolytic cell due to the injection of the AC signal, is determined based on the first voltage and the second voltage.

[0010] The third current that causes the electrolytic cell to output more current due to the injection of the AC signal is determined based on the first current and the second current.

[0011] The third voltage and the third current are converted from time-domain signals to frequency-domain signals;

[0012] Based on the frequency domain signal of the third voltage and the frequency domain signal of the third current, the frequency domain impedance of the electrolytic cell is determined.

[0013] The frequency domain impedance of the electrolytic cell is converted into the time domain impedance of the electrolytic cell.

[0014] Optionally, converting the third voltage and the third current from time-domain signals to frequency-domain signals includes:

[0015] By using Fourier transform, the third voltage and the third current are converted from time-domain signals to frequency-domain signals. The signal values ​​of the frequency-domain signals of the third voltage and the third current are as follows:

[0016]

[0017] in, The signal value of the frequency domain signal of the third voltage. The signal value of the frequency domain signal of the third current. This represents the amplitude spectrum of the frequency domain signal of the third voltage. The frequency domain signal of the third current represents the amplitude spectrum, where ω is the angular frequency of the alternating current signal. The phase spectrum of the frequency domain signal representing the third voltage. The phase spectrum of the frequency domain signal representing the third current.

[0018] Optionally, determining the frequency domain impedance of the electrolytic cell based on the frequency domain signal of the third voltage and the frequency domain signal of the third current includes:

[0019] The frequency domain impedance of the electrolytic cell is determined according to the following formula:

[0020]

[0021] Where, r hyd (ω) is the frequency domain impedance of the electrolytic cell.

[0022] Optionally, controlling the operation of the water electrolysis hydrogen production device includes:

[0023] The reference current is output after the difference between the predetermined reference voltage and the current voltage across the electrolytic cell is input into the first PI controller.

[0024] The difference between the reference current and the current currently output by the hydrogen production power supply is input into the second PI controller, which then outputs the switching control signal of the hydrogen production power supply.

[0025] The switching of the hydrogen production power source is controlled according to the switch control signal.

[0026] Optionally, injecting an AC signal of a predetermined frequency into the current of the reactor includes:

[0027] The difference between the reference current and the current currently output by the hydrogen production power supply, and the sum of the difference with an AC signal of a predetermined frequency, are input into the second PI controller, which then outputs the switching control signal of the hydrogen production power supply.

[0028] Optionally, the method further includes:

[0029] If the impedance of the electrolytic cell is outside the allowable impedance range, a prompt message will be output.

[0030] Optionally, the method further includes:

[0031] The allowable impedance range is determined based on the first current and a predetermined correspondence, wherein the correspondence is the relationship between the current output by the hydrogen production power source and the allowable impedance range of the electrolyzer.

[0032] This disclosure also provides an electrolyzer impedance detection device, wherein the electrolyzer is used in a water electrolysis hydrogen production device, the water electrolysis hydrogen production device includes the electrolyzer and a hydrogen production power source, the hydrogen production power source includes a reactor, and the electrolyzer impedance detection device includes:

[0033] The first detection module is used to detect the first voltage across the electrolyzer and the first current output by the hydrogen production power supply when the water electrolysis hydrogen production device is running under control.

[0034] The second detection module is used to inject an AC signal of a predetermined frequency into the current of the reactor, and to detect the second voltage across the electrolyzer and the second current output by the hydrogen production power supply.

[0035] The first determining module is used to determine the impedance of the electrolytic cell based on the first voltage, the first current, the second voltage, and the second current.

[0036] This disclosure also provides a water electrolysis hydrogen production apparatus, including an electrolyzer, a hydrogen production power source, and a controller, wherein the controller is used to perform the steps of the method provided in this disclosure.

[0037] The above technical solution involves injecting a predetermined frequency AC signal into the current of the reactor in the hydrogen production power supply. Based on the measured values ​​of the voltage across the electrolyzer and the current output from the hydrogen production power supply before and after injection, the impedance of the electrolyzer is determined. This reduces the influence of the reactor's inductive impedance on the electrolyzer impedance measurement results, making the calculated electrolyzer impedance more accurate and providing a reliable basis for electrolyzer maintenance.

[0038] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0039] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0040] Figure 1 This is a schematic diagram of the structure of an electrolytic water hydrogen production device provided in an exemplary embodiment;

[0041] Figure 2 This is a flowchart of an exemplary embodiment of an electrolytic cell impedance detection method;

[0042] Figure 3 This is a schematic diagram of controlling the operation of a hydrogen production device by water electrolysis, provided in an exemplary embodiment.

[0043] Figure 4 This is a schematic diagram of an exemplary embodiment of injecting an alternating current signal of a predetermined frequency;

[0044] Figure 5 This is a schematic diagram of determining the frequency domain impedance of an electrolytic cell provided in an exemplary embodiment;

[0045] Figure 6 This is a structural block diagram of an electrolytic cell impedance detection device provided in an exemplary embodiment. Detailed Implementation

[0046] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0047] It should be noted that all actions involving the acquisition of signals, information, or data in this disclosure are carried out in compliance with the relevant data protection laws and policies of the country where the location is situated, and with authorization from the owner of the relevant device.

[0048] In this disclosure, the electrolyzer can be applied to a water electrolysis hydrogen production device. Figure 1 This is a schematic diagram of a water electrolysis hydrogen production apparatus provided in an exemplary embodiment. Figure 1 As shown, the water electrolysis hydrogen production device may include an electrolyzer 10 and a hydrogen production power supply 20. The hydrogen production power supply 20 includes a switching circuit 21, a reactor 22, and a capacitor 23. The switching circuit 21 includes two switching transistors connected in series. The two ends of the two series-connected switching transistors can be connected to an external power source (U). inThe center point of the two switching tubes is connected to the positive terminal of the electrolytic cell 10 through the reactor 22, the negative terminal of the external power supply is connected to the negative terminal of the electrolytic cell 10, and the capacitor 23 is connected in parallel with the electrolytic cell 10. Figure 1 The middle arrow indicates the direction of current. The hydrogen generator power supply 20 outputs current I. out The terminal voltage U generated at both ends of the electrolytic cell 10 hyd .

[0049] Figure 2 This is a flowchart of an exemplary embodiment of an electrolytic cell impedance detection method. For example... Figure 2 As shown, the method includes steps S201 to S203.

[0050] In step S201, while controlling the operation of the water electrolysis hydrogen production device, the first voltage across the electrolyzer and the first current output by the hydrogen production power supply are detected.

[0051] The control strategy for controlling the operation of the water electrolysis hydrogen production unit can utilize control strategies from related technologies. During operation, the hydrogen production power supply outputs current, generating a terminal voltage across the electrolyzer. The detected voltage across the electrolyzer is referred to hereinafter as the first voltage, and the detected current output by the hydrogen production power supply is referred to hereinafter as the first current.

[0052] In step S202, an AC signal of a predetermined frequency is injected into the current of the reactor, and the second voltage across the electrolyzer and the second current output by the hydrogen production power supply are detected.

[0053] In the control strategy for controlling the operation of the water electrolysis hydrogen production unit, an AC signal of a predetermined frequency is injected into the current of the reactor. That is, an AC signal of a predetermined frequency is added to the actual detected current of the reactor as the current of the reactor, and the water electrolysis hydrogen production unit is continued to be controlled.

[0054] When an alternating current signal of a predetermined frequency is injected, the voltage across the electrolyzer is referred to as the second voltage, and the current output by the hydrogen production power source is referred to as the second current. The first voltage and the first current refer to the values ​​detected before the injection of the alternating current signal of the predetermined frequency.

[0055] To ensure that the ripple of the voltage and current required by the electrolytic cell is within the allowable range, the value of the injected AC signal should be as small as possible, and the frequency should be relatively low, provided that it can be extracted.

[0056] In step S203, the impedance of the electrolytic cell is determined based on the first voltage, the first current, the second voltage, and the second current.

[0057] Since the first voltage, first current, second voltage, and second current include parameters before and after the injection of the AC signal, the electrolytic cell impedance, which ignores the influence of inductive impedance, can be calculated based on these parameters.

[0058] The above technical solution involves injecting a predetermined frequency AC signal into the current of the reactor in the hydrogen production power supply. Based on the measured values ​​of the voltage across the electrolyzer and the current output from the hydrogen production power supply before and after injection, the impedance of the electrolyzer is determined. This reduces the influence of the reactor's inductive impedance on the electrolyzer impedance measurement results, making the calculated electrolyzer impedance more accurate and providing a reliable basis for electrolyzer maintenance.

[0059] Figure 3 This is a schematic diagram illustrating the operation of a hydrogen production device via water electrolysis, provided in an exemplary embodiment. Figure 3 As shown, controlling the operation of a water electrolysis hydrogen production unit may include:

[0060] The predetermined reference voltage U ref The current voltage U across the electrolytic cell hyd The difference is input to the first PI controller 30, which outputs a reference current I. ref ; the reference current I ref The current I currently output by the hydrogen production power supply L The difference is input to the second PI controller 40, which outputs a switching control signal for the hydrogen production power supply. The switching control signal controls the switching of the hydrogen production power supply 20 (the switching circuit 21 in the middle). Specifically, the switching control signal is generated into a PWM pulse signal by the PWM pulse generator 50 and then input into the switching circuit 21 to control the switching of two transistors in the switching circuit 21.

[0061] In other words, before injecting an AC signal of a predetermined frequency, it is possible to utilize Figure 3 The control method shown controls the operation of the water electrolysis hydrogen production unit. Voltage control is an inner loop control, and current control is an outer loop control.

[0062] Figure 4 This is a schematic diagram illustrating the injection of an alternating current signal of a predetermined frequency, provided in an exemplary embodiment. For example... Figure 4 As shown, injecting an AC signal of a predetermined frequency into the current of a reactor can include: using a reference current I... ref The current I currently output by the hydrogen production power supply L The result of the difference operation and the summation with the AC signal f (at a predetermined frequency) is input to the second PI controller 40 and then output as a switching control signal for the hydrogen production power supply (after being generated as a PWM pulse signal by the pulse generator 50).

[0063] In yet another embodiment, Figure 2Based on the first voltage, first current, second voltage, and second current, step S203, which determines the impedance of the electrolytic cell, may include the following steps:

[0064] The third voltage, which increases across the electrolytic cell due to the injection of an AC signal, is determined based on the first and second voltages. The third current, which increases the output of the electrolytic cell due to the injection of an AC signal, is determined based on the first and second currents. The third voltage and third current are converted from time-domain signals to frequency-domain signals. The frequency-domain impedance of the electrolytic cell is determined based on the frequency-domain signals of the third voltage and the third current. The frequency-domain impedance of the electrolytic cell is converted to the time-domain impedance of the electrolytic cell.

[0065] Specifically, at time t before the injection of the low-frequency AC signal, the output current I of the hydrogen production power supply 20 is detected by the self-control and sampling system of the water electrolysis hydrogen production device. out (First current) and electrolytic cell terminal voltage U hyd (First voltage). Among them, the hydrogen production power supply 20 outputs current I. out With the terminal voltage U of the electrolytic cell hyd The relationship between them is as follows:

[0066] U hyd =I out r hyd (1)

[0067] Where, r hyd The impedance of the electrolytic cell.

[0068] Subsequently, by superimposing the electrolyzer current command on the controller, a low-frequency current with frequency f is injected into the hydrogen production power supply reactor. The output current (second current) of the hydrogen production power supply 20 and the terminal voltage (second voltage) of the electrolyzer are then re-detected and obtained as follows: and The relationship between the second current and the second voltage is as follows:

[0069]

[0070] The third current and the third voltage are respectively and

[0071] Solving by combining equations (1) and (2) yields the real-time impedance of the electrolytic cell, as shown in the following equation:

[0072]

[0073] In yet another embodiment, the above-described conversion of the third voltage and third current from time-domain signals to frequency-domain signals includes:

[0074] By using Fourier transform, the third voltage and third current are converted from time-domain signals to frequency-domain signals. The signal values ​​of the frequency-domain signals of the third voltage and the third current are as follows:

[0075]

[0076] in, The signal value of the frequency domain signal of the third voltage. The signal value of the frequency domain signal of the third current. The frequency spectrum of the signal representing the third voltage. The frequency spectrum represents the amplitude of the signal of the third current, where ω is the angular frequency of the alternating current signal. The phase spectrum of the frequency domain signal representing the third voltage. The phase spectrum of the frequency domain signal representing the third current.

[0077] Substituting the result of formula (4) into formula (3), we can obtain the frequency domain impedance of the electrolytic cell as shown in formula (5). The final result calculated by this formula ignores the influence of inductive impedance and has high accuracy.

[0078]

[0079] That is, determining the frequency domain impedance of the electrolytic cell based on the frequency domain signals of the third voltage and the third current can include: determining the frequency domain impedance of the electrolytic cell according to formula (5), where r hyd (ω) is the frequency domain impedance of the electrolytic cell.

[0080] Figure 5 This is a schematic diagram illustrating the determination of the frequency domain impedance of an electrolyzer, provided in an exemplary embodiment. For example... Figure 5 As shown, the third voltage The signal is converted from the time domain to the frequency domain after Fourier transform (FT). Third current The signal is converted from the time domain to the frequency domain after Fourier transform. The frequency domain impedance r of the electrolytic cell is determined according to formula (5). hyd (ω).

[0081] In another embodiment, the method further includes: outputting a prompt message if the impedance of the electrolytic cell is outside the allowable impedance range.

[0082] The allowable impedance range can be a predetermined range, determined through testing based on the characteristics of the electrolytic cell. If the impedance of the electrolytic cell is within the allowable impedance range, it can be considered that the impedance of the electrolytic cell is normal and its internal condition is good. If the impedance of the electrolytic cell is outside the allowable impedance range, it can be considered that the internal condition of the electrolytic cell is poor and maintenance is required. In this case, prompt messages such as flashing lights, beeping, voice prompts, and pop-up windows will be displayed to remind staff to perform timely maintenance and avoid major accidents.

[0083] In another embodiment, the method further includes: determining an allowable impedance range based on a first current and a predetermined correspondence, wherein the correspondence is the relationship between the current output by the hydrogen production power source and the allowable impedance range of the electrolyzer.

[0084] In other words, since the impedance value of the electrolyzer varies slightly under different electrolysis currents, the correspondence between the output current of the hydrogen production power supply and the allowable impedance range of the electrolyzer can be determined in advance through experiments. The allowable impedance range of the electrolyzer corresponding to the first current is then found within this correspondence and used as the allowable impedance range of the current electrolyzer to determine whether to output a prompt message.

[0085] For example, based on historical data and experience, a set of impedances H for the electrolytic cell is compiled in advance, and specific empirical values ​​H{a} are obtained by scanning according to different current levels. i Establish an impedance criterion, where a i This represents the impedance at temperature i. The determination of whether to output a prompt message is based on the following formula:

[0086] |r hyd -a i |<γ (6)

[0087] When the electrolytic cell impedance r hyd With a i When the absolute value of the difference is greater than γ, an alarm is triggered, and the operator conducts a preliminary verification; when the electrolytic cell impedance r hyd With a i When the absolute value of the difference is less than γ, the electrolyzer's impedance is normal, and its internal state is normal. The threshold γ is defined based on the characteristics of electrolyzers with different hydrogen production rates. At temperature i, the allowable impedance range is [a...]. i -γ,a i +γ].

[0088] Figure 6 This is a structural block diagram of an electrolytic cell impedance detection device provided in an exemplary embodiment. (See diagram below.) Figure 6As shown, the electrolytic cell impedance detection device 600 may include a first detection module 601, a second detection module 602, and a first determination module 603.

[0089] The first detection module 601 is used to detect the first voltage across the electrolyzer and the first current output by the hydrogen production power supply when the electrolyzing water hydrogen production device is running.

[0090] The second detection module 602 is used to inject an AC signal of a predetermined frequency into the current of the reactor and to detect the second voltage across the electrolyzer and the second current output by the hydrogen production power supply.

[0091] The first determining module 603 is used to determine the impedance of the electrolytic cell based on the first voltage, the first current, the second voltage, and the second current.

[0092] Optionally, the first determining module 603 includes a first determining submodule, a second determining submodule, a first conversion submodule, a third determining submodule, and a second conversion submodule.

[0093] The first determining submodule is used to determine the third voltage that is increased across the electrolytic cell due to the injection of an AC signal, based on the first voltage and the second voltage.

[0094] The second determining submodule is used to determine the third current that the electrolytic cell will output more due to the injection of an AC signal, based on the first current and the second current.

[0095] The first conversion submodule is used to convert the third voltage and third current from time-domain signals to frequency-domain signals.

[0096] The third determining submodule is used to determine the frequency domain impedance of the electrolytic cell based on the frequency domain signals of the third voltage and the third current.

[0097] The second conversion submodule is used to convert the frequency domain impedance of the electrolytic cell into the time domain impedance of the electrolytic cell.

[0098] Optionally, the first conversion submodule is used to convert the third voltage and third current from time-domain signals to frequency-domain signals using Fourier transform. The signal values ​​of the frequency-domain signals of the third voltage and the third current are as follows:

[0099]

[0100] in, The signal value of the frequency domain signal of the third voltage. The signal value of the frequency domain signal of the third current. The frequency spectrum of the signal representing the third voltage. The frequency spectrum represents the amplitude of the signal of the third current, where ω is the angular frequency of the alternating current signal. The phase spectrum of the frequency domain signal representing the third voltage. The phase spectrum of the frequency domain signal representing the third current.

[0101] Optionally, the third determining submodule is used to determine the frequency domain impedance of the electrolyzer according to the following formula:

[0102]

[0103] Where, r hyd This is the frequency domain impedance of the electrolytic cell.

[0104] Optionally, the electrolyzer impedance detection device 600 may include a control module, which is used to: input the difference between a predetermined reference voltage and the current voltage across the electrolyzer into a first PI controller and output a reference current; input the difference between the reference current and the current currently output by the hydrogen production power supply into a second PI controller and output a switching control signal for the hydrogen production power supply; and control the switching of the hydrogen production power supply according to the switching control signal.

[0105] Optionally, the control module is also used to: take the difference between the reference current and the current currently output by the hydrogen production power supply, and then sum the result with an AC signal of a predetermined frequency, input the result into the second PI controller, and then output the switching control signal of the hydrogen production power supply.

[0106] Optionally, the electrolytic cell impedance detection device 600 includes an output module.

[0107] The output module is used to output a warning message if the impedance of the electrolytic cell is outside the allowable impedance range.

[0108] Optionally, the electrolytic cell impedance detection device 600 includes a second determining module.

[0109] The second determining module is used to determine the allowable impedance range based on the first current and a predetermined correspondence. This correspondence is the relationship between the current output by the hydrogen production power source and the allowable impedance range of the electrolyzer.

[0110] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0111] The above technical solution involves injecting a predetermined frequency AC signal into the current of the reactor in the hydrogen production power supply. Based on the measured values ​​of the voltage across the electrolyzer and the current output from the hydrogen production power supply before and after injection, the impedance of the electrolyzer is determined. This reduces the influence of the reactor's inductive impedance on the electrolyzer impedance measurement results, making the calculated electrolyzer impedance more accurate and providing a reliable basis for electrolyzer maintenance.

[0112] This disclosure also provides an electrolytic water hydrogen production apparatus, including an electrolyzer, a hydrogen production power source, and a controller, the controller being used to perform the steps of the method described above provided in this disclosure.

[0113] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0114] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0115] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A method for detecting the impedance of an electrolytic cell, characterized in that, The electrolyzer is used in a water electrolysis hydrogen production device, which includes the electrolyzer and a hydrogen production power source, the power source including a reactor. The method includes: When controlling the operation of the water electrolysis hydrogen production device, a first voltage across the electrolyzer and a first current output by the hydrogen production power supply are detected; wherein, controlling the operation of the water electrolysis hydrogen production device includes: inputting the difference between a predetermined reference voltage and the current voltage across the electrolyzer into a first PI controller, and then outputting a reference current; inputting the difference between the reference current and the current currently output by the hydrogen production power supply into a second PI controller, and then outputting a switch control signal for the hydrogen production power supply; and controlling the switch of the hydrogen production power supply according to the switch control signal; An AC signal of a predetermined frequency is injected into the current of the reactor, and a second voltage across the electrolyzer and a second current output by the hydrogen production power supply are detected; wherein, injecting an AC signal of a predetermined frequency into the current of the reactor includes: taking the difference between the reference current and the current currently output by the hydrogen production power supply, and then summing the result with the AC signal of the predetermined frequency, inputting the result into the second PI controller, and then outputting a switching control signal for the hydrogen production power supply; The impedance of the electrolytic cell is determined based on the first voltage, the first current, the second voltage, and the second current.

2. The method according to claim 1, characterized in that, Determining the impedance of the electrolytic cell based on the first voltage, the first current, the second voltage, and the second current includes: A third voltage, which increases across the electrolytic cell due to the injection of the AC signal, is determined based on the first voltage and the second voltage. The third current that causes the electrolytic cell to output more current due to the injection of the AC signal is determined based on the first current and the second current. The third voltage and the third current are converted from time-domain signals to frequency-domain signals; The frequency domain impedance of the electrolytic cell is determined based on the frequency domain signal of the third voltage and the frequency domain signal of the third current. The frequency domain impedance of the electrolytic cell is converted into the time domain impedance of the electrolytic cell.

3. The method according to claim 2, characterized in that, The step of converting the third voltage and the third current from time-domain signals to frequency-domain signals includes: By using Fourier transform, the third voltage and the third current are converted from time-domain signals to frequency-domain signals. The signal values ​​of the frequency-domain signals of the third voltage and the third current are as follows: in, The signal value of the frequency domain signal of the third voltage. The signal value of the frequency domain signal of the third current. This represents the amplitude spectrum of the frequency domain signal of the third voltage. This represents the amplitude spectrum of the frequency domain signal of the third current. The angular frequency of the alternating current signal. The phase spectrum of the frequency domain signal representing the third voltage. The phase spectrum of the frequency domain signal representing the third current.

4. The method according to claim 3, characterized in that, Determining the frequency domain impedance of the electrolytic cell based on the frequency domain signal of the third voltage and the frequency domain signal of the third current includes: The frequency domain impedance of the electrolytic cell is determined according to the following formula: in, The frequency domain impedance of the electrolytic cell is given.

5. The method according to claim 1, characterized in that, The method further includes: If the impedance of the electrolytic cell is outside the allowable impedance range, a prompt message will be output.

6. The method according to claim 5, characterized in that, The method further includes: The allowable impedance range is determined based on the first current and a predetermined correspondence, wherein the correspondence is the relationship between the current output by the hydrogen production power source and the allowable impedance range of the electrolyzer.

7. An electrolytic cell impedance detection device, characterized in that, The electrolyzer is used in a water electrolysis hydrogen production device, which includes the electrolyzer and a hydrogen production power source. The hydrogen production power source includes a reactor. The electrolyzer impedance detection device includes: The first detection module is used to detect the first voltage across the electrolyzer and the first current output by the hydrogen production power supply when the water electrolysis hydrogen production device is running under control. The second detection module is used to inject an AC signal of a predetermined frequency into the current of the reactor, and to detect the second voltage across the electrolyzer and the second current output by the hydrogen production power supply. The first determining module is used to determine the impedance of the electrolytic cell based on the first voltage, the first current, the second voltage, and the second current. The control module is used to input the difference between a predetermined reference voltage and the current voltage across the electrolyzer into a first PI controller and output a reference current; input the difference between the reference current and the current currently output by the hydrogen production power supply into a second PI controller and output a switching control signal for the hydrogen production power supply; control the switching of the hydrogen production power supply according to the switching control signal; and input the difference between the reference current and the current currently output by the hydrogen production power supply, and then sum the result with an AC signal of a predetermined frequency, into the second PI controller and output a switching control signal for the hydrogen production power supply.

8. A water electrolysis hydrogen production device, characterized in that, It includes an electrolyzer, a hydrogen production power source, and a controller, the controller being used to perform the steps of the method according to any one of claims 1-6.

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