Method and system for measuring alternating current impedance of high-power electrolytic cell

Abstract

The invention provides a method and a system for measuring alternating current impedance of a high-power electrolytic cell. The method comprises the following steps: connecting positive and negative electrodes of an electrolytic power supply with positive and negative electrodes of an electrolytic cell of water electrolysis hydrogen production equipment; connecting a voltage signal connection interface on each daughter board of the electrolytic cell with a data acquisition device; a current transformer is installed on a connecting cable between the negative electrode of the electrolysis power source and the negative electrode of the electrolysis bath, and the current transformer is connected with a data acquisition device; when the water electrolysis hydrogen production equipment runs to a preset temperature, an electrolysis power supply is controlled to output sine disturbance current in a preset frequency band; the data acquisition device acquires time domain data of the electrolytic cell; analyzing the time domain data of the electrolytic cell through a preset alternating current impedance analysis algorithm to obtain impedance information of each small chamber under different frequencies; according to the method, alternating-current impedance measurement can be carried out on each small electrolysis chamber of the water electrolysis hydrogen production electrolytic cell, fault early warning and fault analysis of the electrolytic cell are carried out through alternating-current impedance data, and stable operation of hydrogen production equipment is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of electrolytic cell alternating current impedance measurement, and in particular relates to a method and system for measuring the alternating current impedance of a high-power electrolytic cell. Background Art

[0002] The AC impedance of an electrolytic cell is a technique that treats the working electrochemical device as an electrochemical black box system with unknown internal structure or state, applies a fixed frequency or a group of different frequencies of small amplitude sinusoidal perturbation current (or voltage), measures the output response signal voltage (or current), and studies the internal state and kinetic process of the electrochemical device by analyzing the transfer function of the relationship between the response and the perturbation. The measurement of the AC impedance of an electrolytic cell mainly includes three parts: first, it can output sinusoidal excitation power supplies of different frequencies with DC bias, and load the excitation power supplies to the electrolytic cell under test; second, it performs high-frequency data acquisition of the voltage and total current of each cell of the electrolytic cell, and it is necessary to ensure high precision and high clock synchronization of all data; third, based on the broadband calculation method, the voltage and current signals collected in the time domain are converted to the frequency domain for calculation, and the AC impedance parameters of the electrolytic cell under different frequency excitation power supplies are obtained.

[0003] At present, the AC impedance of the electrolyzer of water electrolysis hydrogen production equipment is mainly measured by electrochemical workstations, but the output power of electrochemical workstations is low, and they can only drive single-cell low-power electrolyzers and measure AC impedance. However, electrolyzers for current industrial applications generally have many chambers and large operating currents, and electrochemical workstations cannot meet the requirements for AC impedance measurement of electrolyzers for industrial applications; and the current high-frequency, high-precision, clock-synchronized data acquisition devices have a small number of channels, generally eight channels, and can only collect data for 7 chambers and 1 current of the electrolyzer. It is impossible to perform voltage and current data measurement on all chambers of the electrolyzer in the same time and space and then analyze the AC impedance.

[0004] Therefore, how to provide a method and system for measuring the AC impedance of a high-power electrolytic cell has become a technical problem that urgently needs to be solved in this field. Summary of the invention

[0005] The object of the present invention is to provide a method and system for measuring the AC impedance of a high-power electrolytic cell.

[0006] According to a first aspect of the present invention, a method for measuring the AC impedance of a high-power electrolyzer is provided, the method comprising:

[0007] Step S1: connecting the positive and negative electrodes of an electrolytic power source to the positive and negative electrodes of an electrolytic cell of a water electrolysis hydrogen production device, wherein the electrolytic power source outputs a sinusoidal disturbance current;

[0008] Step S2: connecting the voltage signal connection interface on each sub-board of the electrolytic cell to a data acquisition device;

[0009] Step S3: installing a current transformer on a connecting cable between the negative electrode of the electrolysis power source and the negative electrode of the electrolytic cell, and connecting the current transformer to the data acquisition device to collect a transformer signal through the data acquisition device;

[0010] Step S4: starting the water electrolysis hydrogen production equipment;

[0011] Step S5: When the water electrolysis hydrogen production equipment runs to a preset temperature, controlling the electrolysis power supply to output a sinusoidal disturbance current of a preset frequency band;

[0012] Step S6: the data acquisition device acquires the time domain data of the electrolytic cell;

[0013] Step S7: After all the time domain data under the preset frequency bands are collected, the time domain data of the electrolytic cell is analyzed by a preset AC impedance analysis algorithm to obtain the impedance information of each chamber under different frequencies.

[0014] Optionally, in step S5, the preset frequency band has a value range of 0.1 Hz to 10 KHz.

[0015] Optionally, in step S6, the electrolytic cell time domain data includes: voltage signals of each chamber and a total current signal of the electrolytic cell.

[0016] Optionally, the step S7 specifically includes:

[0017] Step S71: Perform Fourier transform on the time domain data of the electrolytic cell to obtain a frequency domain complex array of the voltage of each cell and the total current of the electrolytic cell;

[0018] Step S72: Calculate the amplitude of the frequency domain complex array of each cell voltage and the total current of the electrolytic cell to obtain the voltage amplitude and current amplitude of each cell;

[0019] Step S73: Calculate the phase of the frequency domain complex array of each cell voltage and the total current of the electrolytic cell to obtain the voltage phase and current phase of each cell;

[0020] Step S74: Divide the voltage amplitude of each chamber by the current amplitude to obtain the AC impedance modulus data of each chamber in the corresponding frequency band, and subtract the voltage phase of each chamber from the current phase to obtain the phase angle of each chamber in the corresponding frequency band.

[0021] According to a second aspect of the present invention, there is provided a high-power electrolyzer AC impedance measurement system, the system comprising: a water electrolysis hydrogen production device, an electrolysis power supply, a data acquisition device and a current transformer;

[0022] The positive and negative electrodes of the electrolysis power supply are connected to the positive and negative electrodes of the electrolyzer of the water electrolysis hydrogen production equipment, and the electrolysis power supply is used to output a sinusoidal disturbance current; the voltage signal connection interface on each sub-board of the electrolyzer is connected to the data acquisition device; the current transformer is installed on the connecting cable between the negative electrode of the electrolysis power supply and the negative electrode of the electrolyzer, and the current transformer is connected to the data acquisition device to collect transformer signal data through the data acquisition device; the data acquisition device is used to collect electrolyzer time domain data and transformer signal data and collect data for analysis and processing;

[0023] When starting the test, the water electrolysis hydrogen production equipment is started first. When the water electrolysis hydrogen production equipment runs to a preset temperature, the electrolysis power supply is controlled to output a sinusoidal perturbation current of a preset frequency band; the data acquisition device obtains the time domain data of the electrolytic cell; after the time domain data in all preset frequency bands are acquired, the time domain data of the electrolytic cell is analyzed by a preset AC impedance analysis algorithm to obtain the impedance information of each chamber at different frequencies.

[0024] Optionally, the electrolysis power supply is an integrated power supply, an electronic load power supply or an excitation injection power supply.

[0025] Optionally, the current transformer is a Hall transformer.

[0026] Optionally, the data acquisition device includes a voltage signal connection interface, a differential voltage conversion module and an analog-to-digital conversion module arranged on each daughter board, and a core processor arranged on the mother board;

[0027] The voltage signal connection interface is used to receive the voltage signals of each chamber, the differential voltage conversion module is used to convert the chamber voltage signal into a single-ended voltage signal with a common ground, the analog-to-digital conversion module is used to convert the single-ended voltage signal with a common ground into a voltage digital signal and then send it to the core processor, and the core processor is used to process the voltage digital signal.

[0028] Optionally, the differential voltage conversion module uses a high common-mode differential voltage operational amplifier.

[0029] Optionally, the data acquisition device includes 6 daughter board slots, supporting data acquisition of a maximum of 144 channels.

[0030] The beneficial effects brought by the present invention are as follows:

[0031] It can be seen from the above scheme that the embodiment of the present invention provides a method and system for measuring the AC impedance of a high-power electrolytic cell, which has the following beneficial effects:

[0032] The high-power electrolyzer AC impedance measurement method and system of the present invention can perform AC impedance measurement on each electrolysis chamber of a water electrolysis hydrogen production electrolyzer, perform fault warning and fault analysis of the electrolyzer through AC impedance data, and ensure stable operation of the hydrogen production equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic flow chart of a method for measuring AC impedance of a high-power electrolytic cell provided according to an embodiment;

[0034] Figure 2 A schematic diagram of the structure of a high-power electrolytic cell AC impedance measurement system provided according to an embodiment Figure 1 ;

[0035] Figure 3 A schematic diagram of the structure of a high-power electrolytic cell AC impedance measurement system provided according to an embodiment Figure 2 ;

[0036] Figure 4 A schematic diagram of the structure of a high-power electrolytic cell AC impedance measurement system provided according to an embodiment Figure 3 ;

[0037] Figure 5 A time domain diagram of a voltage and current signal provided according to an embodiment;

[0038] Figure 6 It is a schematic diagram of the structure of a data acquisition device provided according to an embodiment. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] According to a first aspect of the present invention, a method for measuring the AC impedance of a high-power electrolyzer is provided. Figure 1 As shown, the method includes:

[0041] Step S1: connecting the positive and negative electrodes of an electrolytic power source to the positive and negative electrodes of an electrolytic cell of a water electrolysis hydrogen production device, wherein the electrolytic power source outputs a sinusoidal disturbance current;

[0042] Step S2: connecting the voltage signal connection interface on each sub-board of the electrolytic cell to a data acquisition device;

[0043] Step S3: installing a current transformer on a connecting cable between the negative electrode of the electrolysis power source and the negative electrode of the electrolytic cell, and connecting the current transformer to the data acquisition device to collect a transformer signal through the data acquisition device;

[0044] Step S4: starting the water electrolysis hydrogen production equipment;

[0045] Step S5: When the water electrolysis hydrogen production equipment runs to a preset temperature, controlling the electrolysis power supply to output a sinusoidal disturbance current of a preset frequency band;

[0046] Step S6: the data acquisition device acquires the time domain data of the electrolytic cell;

[0047] Step S7: After all the time domain data under the preset frequency bands are collected, the time domain data of the electrolytic cell is analyzed by a preset AC impedance analysis algorithm to obtain the impedance information of each chamber under different frequencies.

[0048] Optionally, in the high-power electrolyzer AC impedance measurement method of the embodiment of the present invention, in step S5, the value range of the preset frequency band is 0.1 Hz to 10 KHz.

[0049] It should be noted that since the electrolytic cell distinguishes between positive and negative poles, it is necessary to ensure that the electrolytic power supply has a DC bias (with a disturbance current). If a pure AC excitation signal is used, the positive and negative poles of the electrolytic cell are constantly switched, which will damage the electrodes.

[0050] In this embodiment, the electrolytic power supply (ie, the excitation power supply) continuously outputs sinusoidal excitation signals of different frequencies according to a preset sweep frequency program. The sweep frequency is 10 KHz-0.1 Hz, and there is a slight pause between different frequencies.

[0051] Optionally, in the high-power electrolytic cell AC impedance measurement method of the embodiment of the present invention, in step S6, the electrolytic cell time domain data includes: each chamber voltage signal and the electrolytic cell total current signal.

[0052] Optionally, step S7 in the method for measuring the AC impedance of a high-power electrolyzer according to an embodiment of the present invention specifically includes:

[0053] Step S71: Perform Fourier transform on the time domain data of the electrolytic cell to obtain a frequency domain complex array of the voltage of each cell and the total current of the electrolytic cell;

[0054] Step S72: Calculate the amplitude of the frequency domain complex array of each cell voltage and the total current of the electrolytic cell to obtain the voltage amplitude and current amplitude of each cell;

[0055] Step S73: Calculate the phase of the frequency domain complex array of each cell voltage and the total current of the electrolytic cell to obtain the voltage phase and current phase of each cell;

[0056] Step S74: Divide the voltage amplitude of each chamber by the current amplitude to obtain the AC impedance modulus data of each chamber in the corresponding frequency band, and subtract the voltage phase of each chamber from the current phase to obtain the phase angle of each chamber in the corresponding frequency band.

[0057] Specifically, the processing process of the preset AC impedance analysis algorithm in the AC impedance measurement method of a high-power electrolytic cell in an embodiment of the present invention is as follows: the time domain data of the voltage signals of all the chambers of the electrolytic cell and the total current signal of the electrolytic cell can be collected through the electrolytic power supply and the clock-synchronized data acquisition device. The above time domain data is Fourier transformed and converted to the frequency domain to obtain the complex arrays of the voltage of each chamber and the total current in the frequency domain. The amplitude of the frequency domain complex array of the voltage and current of each chamber is calculated. The amplitude of the chamber voltage is divided by the current amplitude, which is the AC impedance modulus data of this chamber at this frequency, denoted as R; the phase of the frequency domain complex array of the voltage and current of each chamber is calculated. The current phase minus the chamber voltage phase is the phase angle of this chamber at this frequency, denoted as θ; another way to express the AC impedance result is the real part R real , imaginary part R img , the conversion formula is as follows:

[0058] R real =R*cosθ (1)

[0059] R img =R*sinθ (2)

[0060] The specific implementation steps of the high-power electrolyzer AC impedance measurement method of the embodiment of the present invention are as follows:

[0061] 1) Prepare a set of water electrolysis hydrogen production equipment that can operate normally;

[0062] 2) Connect the positive and negative electrodes of the electrolytic power supply that can output sinusoidal disturbance current to the positive and negative electrodes of the electrolytic cell;

[0063] 3) Leading out voltage signals on each sub-board of the electrolytic cell to a data acquisition device;

[0064] 4) Install the Hall transformer on the cable or copper busbar to be tested, and introduce the transformer signal into the acquisition card of the data acquisition device;

[0065] 5) The water electrolysis hydrogen production equipment is started normally and runs to the preset temperature;

[0066] 6) The data acquisition device starts running;

[0067] 7) The electrolysis power supply starts to output a sinusoidal disturbance current of 0.1Hz to 10KHz;

[0068] 8) After the entire frequency band is tested, the data acquisition device stops working and all collected data are exported;

[0069] 9) The impedance information of each chamber at different frequencies is analyzed through the AC impedance analysis algorithm.

[0070] According to a second aspect of the present invention, a high-power electrolytic cell AC impedance measurement system is provided. Figure 2-4 As shown, the system includes: water electrolysis hydrogen production equipment, electrolysis power supply 1, data acquisition device 2 and current transformer 3;

[0071] The positive and negative electrodes of the electrolysis power supply 1 are connected to the positive and negative electrodes of the electrolyzer 4 of the water electrolysis hydrogen production equipment, and the electrolysis power supply 1 is used to output a sinusoidal disturbance current; the voltage signal connection interface on each sub-board of the electrolyzer 4 is connected to the data acquisition device 2; the current transformer 3 is installed on the connecting cable between the negative electrode of the electrolysis power supply 1 and the negative electrode of the electrolyzer 4, and the current transformer 3 is connected to the data acquisition device 2 to collect transformer signal data through the data acquisition device 2; the data acquisition device 2 is used to collect electrolyzer time domain data and transformer signal data and collect data for analysis and processing;

[0072] When starting the test, the water electrolysis hydrogen production equipment is started first. When the water electrolysis hydrogen production equipment runs to a preset temperature, the electrolysis power supply 1 is controlled to output a sinusoidal disturbance current of a preset frequency band; the data acquisition device 2 obtains the time domain data of the electrolytic cell; after the time domain data under all preset frequency bands are acquired, the time domain data of the electrolytic cell is analyzed by a preset AC impedance analysis algorithm to obtain the impedance information of each chamber at different frequencies.

[0073] Optionally, the electrolytic power supply 1 in the high-power electrolytic cell AC impedance measurement system of the embodiment of the present invention is an integrated power supply, an electronic load power supply or an excitation injection power supply.

[0074] Specifically, in this embodiment, the electrolysis power supply can output currents with sinusoidal excitations of different frequencies with DC bias. The DC bias means that a sinusoidal disturbance is superimposed on the normal electrolysis current. For example, a power supply device outputs a voltage and current signal with DC bias, as shown in the time domain diagram Figure 5 As shown (the horizontal axis in the figure is time and the vertical axis is voltage).

[0075] Since the electrolytic cell distinguishes between positive and negative electrodes, it is necessary to ensure that the power supply has a DC bias. If a pure AC excitation signal is used, the positive and negative electrodes of the electrolytic cell will be constantly switched, which will damage the electrodes. There are three types of electrolytic power supplies with DC bias: one is an integrated power supply (such as Figure 2As shown), it is mostly used in electrochemical workstations. This power supply can directly output an excitation signal containing a DC bias. This power supply has a high degree of integration and the output excitation signal has good quality. However, this type of power supply is relatively expensive and the output power is generally small. Even when an amplifier is used, the maximum DC bias is generally only 20-30A, superimposed with an AC disturbance signal of 2-3A.

[0076] The second is to use the form of electronic load shunt (such as Figure 3 As shown in the figure, an ordinary DC power supply is used to supply power to the electrolytic cell and the electronic load at the same time. The electrolytic cell and the electronic load are in parallel structure. The ordinary DC power supply outputs a constant current to the electrolytic cell and the electronic load. The electronic load continuously adjusts the amount of current divided to achieve the purpose of presenting a sinusoidal current in the electrolytic cell loop.

[0077] The third is to use a DC constant current power supply (such as Figure 4 As shown in the figure, an excitation injection power supply is superimposed. The DC constant current power supply only outputs DC, and the excitation injection power supply outputs an additional sinusoidal perturbation excitation signal. The voltage and current after the superposition of the two are loaded onto the electrolytic cell together.

[0078] Optionally, the current transformer in the high-power electrolyzer AC impedance measurement system of the embodiment of the present invention is a Hall transformer.

[0079] Optionally, the data acquisition device in the high-power electrolyzer AC impedance measurement system of the embodiment of the present invention includes a voltage signal connection interface, a differential voltage conversion module and an analog-to-digital conversion module arranged on each daughter board, and a core processor arranged on the mother board;

[0080] The voltage signal connection interface is used to receive the voltage signals of each chamber, the differential voltage conversion module is used to convert the chamber voltage signal into a single-ended voltage signal with a common ground, the analog-to-digital conversion module is used to convert the single-ended voltage signal with a common ground into a voltage digital signal and then send it to the core processor, and the core processor is used to process the voltage digital signal.

[0081] Optionally, the differential voltage conversion module in the high-power electrolyzer AC impedance measurement system of the embodiment of the present invention adopts a high common-mode differential voltage operational amplifier.

[0082] Optionally, the data acquisition device in the high-power electrolyzer AC impedance measurement system of the embodiment of the present invention includes 6 daughter board slots, supporting data acquisition of a maximum of 144 channels.

[0083] In this embodiment, the cell voltage needs to be converted into a single-ended voltage using a differential operational amplifier before it can be directly collected using a data collection device.

[0084] In this embodiment, the current transformer adopts a Hall transformer. The Hall transformer outputs a current signal, which is converted into a voltage signal through a high-precision power resistor and then input into a data acquisition device for collection.

[0085] The sinusoidal disturbance frequency output by the AC impedance test power supply is generally 0.1Hz-10KHz, or even higher. Based on Shannon's sampling theorem, the sampling frequency should be greater than or equal to twice the highest frequency in the analog signal spectrum, so the data sampling device needs to have a high-frequency acquisition function. The data acquisition device of this embodiment supports a maximum acquisition frequency of 200KHz, and the acquisition frequency is adjustable from 0.1Hz to 200KHz.

[0086] The AC impedance of the electrolytic cell needs to be analyzed in the frequency domain, so it is necessary to ensure the clock synchronization of the voltage and total current sampling of all chambers, otherwise it will cause a large error in the phase angle analysis. The number of chambers in the electrolytic cell ranges from a few to hundreds, and the online AC impedance measurement is performed on each electrolytic cell chamber. A powerful data acquisition device is required to achieve clock synchronization of all voltage and current acquisition channels. For example, when the excitation model is 10KHz, the period of the sine curve is 100us, and the phase deviation of the voltage and current is only about 1% of the period, so the clock synchronization error must be at the ns level.

[0087] The measurement of the electrolytic cell AC impedance in this embodiment requires a very high accuracy of the data acquisition device, requiring the voltage and current acquisition accuracy to meet the accuracy better than 0.2% in the entire test range. Due to the requirements of impedance measurement, the acquisition device needs to be able to achieve high acquisition frequency, high sampling accuracy, high clock synchronization, large-scale multi-channel real-time acquisition, high-speed data storage and transmission and other functions.

[0088] Specifically, the data acquisition device of this embodiment mainly includes: voltage signal connection interface, differential voltage conversion, analog-to-digital conversion, FPGA+ARM core processor, Gigabit network port, high-speed Flash memory, expandable SD card, USB interface, power supply, etc. Figure 6 shown.

[0089] (1) The voltage signal connection interface adopts DB25 pin connector design, which is convenient for plugging and unplugging.

[0090] (2) The voltage of a single electrolytic cell is about 2V, but the voltage generated by multiple cells in cascade is very large, so the impact of high-voltage common mode and high-voltage protection need to be considered. Therefore, a high common-mode differential voltage operational amplifier is used to convert the differential voltage signal of each cell into a single-ended voltage signal with a common ground, which is then collected by the analog-to-digital conversion chip.

[0091] (3) The circuit board structure is designed as a structure with 1 main board and multiple sub-boards.

[0092] (4) The daughter board includes: 1 DB25 signal connection interface, 24 differential voltage chips, and 3 8-channel analog-to-digital conversion chips designed on a PCB board to realize the analog-to-digital conversion of 24 differential voltages.

[0093] (4) Since the electrolytic cell has a large number of chambers and requires a large number of channels for data acquisition, up to 6 daughter board slots are designed on the mainboard, and a PCIE interface is used, which is easy and reliable to install and supports up to 144 channels of data acquisition.

[0094] (5) AC impedance measurement requires that all channels are collected synchronously, with a synchronization error of ≤0.1us. The 8 acquisition channels of a single AD7606 chip are collected synchronously, but the synchronization between multiple AD7606 chips requires the driver chip to be synchronized in the drive control. In addition, the total bandwidth of 144 channels is above 20M Byte. There is no mature SOC to solve this problem, so the mainboard uses FPGA interface design plus ARM structure to collect and control all data acquisition chips, and write a large amount of data to the SD card.

[0095] (6) The mainboard is equipped with a Gigabit Ethernet port and a built-in Linux embedded operating system. After the operating software is installed on the host computer, operations such as starting and stopping the acquisition and setting the acquisition time can be performed through the Ethernet port. After the acquisition command is initiated, a large amount of data will be saved in real time in the mainboard's memory. The mainboard is equipped with an onboard Flash memory chip, which can store the collected data at high speed, but the memory is small. At the same time, the mainboard is equipped with an SD card expansion interface, which can be expanded with a large memory SD card. The mainboard is equipped with a USB interface. After the data acquisition is completed, the data stored in the mainboard can be copied through the USB interface. The mainboard is equipped with a Gigabit Ethernet port. After the data acquisition is completed, the data can be downloaded through the Ethernet port.

[0096] (7) During the PCB design process, the trace lengths of the main board and sub-board should be kept consistent to ensure the clock synchronization performance of the signal.

[0097] (8) Data acquisition of voltage and current must ensure data synchronization, in addition to clock synchronization for all AD data acquisition channels. The response speed and sampling accuracy of the current transformer are two key points that need to be paid attention to. If the response speed of the current transformer is slow, it will cause phase lag, and low transformer accuracy will affect the calculation results. Considering comprehensive technology and cost, a current transformer based on the Hall principle is used. The following matters need to be noted when installing the Hall transformer:

[0098] 1) For the tested cable or copper busbar, try to place it in the center of the transformer perforation to reduce the position error;

[0099] 2) In addition to the transformer perforation, try to reduce strong current around it to reduce external magnetic field interference;

[0100] 3) The transformer is powered by a bipolar DC linear power supply to reduce ripple output;

[0101] 4) Hall transformers generally output current signals. For example, a certain type of Hall transformer has a current range of 3000A and an output signal of 600ma. The data acquisition card cannot directly collect current signals, so a sampling resistor is required to convert the current signal into a voltage signal and then connect it to the data acquisition device. The sampling resistor needs to meet the high-frequency non-inductive characteristics, high precision, appropriate power selection and heat dissipation to ensure that the sampling resistor does not introduce additional phase error and accuracy error.

[0102] It should be noted that the system of this embodiment can measure the AC impedance of the electrolyzer of water electrolysis hydrogen production equipment, including but not limited to alkaline, PEM, AEM and other electrolyzers.

[0103] The AC impedance measurement data of the actual electrolytic cell can be used to quantitatively analyze the health of the electrolytic cell. According to the changing trend of the impedance data, fault warning and fault analysis of the electrolytic cell can be performed.

[0104] The electrolyzer is the core component of the hydrogen production device, and it accounts for a relatively high cost of the entire hydrogen production equipment. When the electrolyzer cannot work properly, the entire equipment cannot operate. In the future, when water electrolysis hydrogen production devices are used on a large scale as a new energy storage device, higher demands will be placed on the reliability and stability of the electrolyzer. However, there is currently no means for quantitative analysis of the operating status of the electrolyzer. The high-power electrolyzer AC impedance measurement method and system of the embodiment of the present invention can perform AC impedance measurement on each electrolytic chamber of a water electrolysis hydrogen production electrolyzer, and perform fault warning and fault analysis of the electrolyzer through AC impedance data to ensure the stable operation of the hydrogen production equipment.

[0105] The above are preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for measuring AC impedance of a high-power electrolytic cell, characterized in that: The method comprises: Step S1: connecting the positive and negative electrodes of an electrolytic power source to the positive and negative electrodes of an electrolytic cell of a water electrolysis hydrogen production device, wherein the electrolytic power source outputs a sinusoidal disturbance current; Step S2: connecting the voltage signal connection interface on each sub-board of the electrolytic cell to a data acquisition device; Step S3: installing a current transformer on a connecting cable between the negative electrode of the electrolysis power source and the negative electrode of the electrolytic cell, and connecting the current transformer to the data acquisition device to collect a transformer signal through the data acquisition device; Step S4: starting the water electrolysis hydrogen production equipment; Step S5: when the water electrolysis hydrogen production equipment runs to a preset temperature, controlling the electrolysis power supply to output a sinusoidal disturbance current of a preset frequency band; Step S6: the data acquisition device acquires the time domain data of the electrolytic cell; Step S7: After all the time domain data under the preset frequency bands are collected, the time domain data of the electrolytic cell is analyzed by a preset AC impedance analysis algorithm to obtain the impedance information of each chamber under different frequencies.

2. The method for measuring AC impedance of a high-power electrolyzer according to claim 1, characterized in that: In the step S5, the preset frequency band has a value range of 0.1 Hz to 10 KHz.

3. The method for measuring AC impedance of a high-power electrolyzer according to claim 1, characterized in that: In step S6, the electrolytic cell time domain data includes: each chamber voltage signal and the electrolytic cell total current signal.

4. The method for measuring AC impedance of a high-power electrolyzer according to claim 3, characterized in that: The step S7 specifically includes: Step S71: Perform Fourier transform on the time domain data of the electrolytic cell to obtain a frequency domain complex array of the voltage of each cell and the total current of the electrolytic cell; Step S72: Calculate the amplitude of the frequency domain complex array of each cell voltage and the total current of the electrolytic cell to obtain the voltage amplitude and current amplitude of each cell; Step S73: Calculate the phase of the frequency domain complex array of each cell voltage and the total current of the electrolytic cell to obtain the voltage phase and current phase of each cell; Step S74: Divide the voltage amplitude of each chamber by the current amplitude to obtain the AC impedance modulus data of each chamber in the corresponding frequency band, and subtract the voltage phase of each chamber from the current phase to obtain the phase angle of each chamber in the corresponding frequency band.

5. A high-power electrolytic cell AC impedance measurement system, characterized in that: The system comprises: water electrolysis hydrogen production equipment, electrolysis power supply, data acquisition device and current transformer; The positive and negative electrodes of the electrolysis power supply are connected to the positive and negative electrodes of the electrolyzer of the water electrolysis hydrogen production equipment, and the electrolysis power supply is used to output a sinusoidal disturbance current; the voltage signal connection interface on each sub-board of the electrolyzer is connected to the data acquisition device; the current transformer is installed on the connecting cable between the negative electrode of the electrolysis power supply and the negative electrode of the electrolyzer, and the current transformer is connected to the data acquisition device to collect transformer signal data through the data acquisition device; the data acquisition device is used to collect electrolyzer time domain data and transformer signal data and collect data for analysis and processing; When starting the test, the water electrolysis hydrogen production equipment is started first. When the water electrolysis hydrogen production equipment runs to a preset temperature, the electrolysis power supply is controlled to output a sinusoidal perturbation current of a preset frequency band; the data acquisition device obtains the time domain data of the electrolytic cell; after the time domain data in all preset frequency bands are acquired, the time domain data of the electrolytic cell is analyzed by a preset AC impedance analysis algorithm to obtain the impedance information of each chamber at different frequencies.

6. The high-power electrolytic cell AC impedance measurement system according to claim 5, characterized in that: The electrolysis power supply is an integrated power supply, an electronic load power supply or an excitation injection power supply.

7. The high-power electrolytic cell AC impedance measurement system according to claim 5, characterized in that: The current transformer is a Hall transformer.

8. The high-power electrolytic cell AC impedance measurement system according to claim 5, characterized in that: The data acquisition device includes a voltage signal connection interface, a differential voltage conversion module and an analog-to-digital conversion module arranged on each daughter board, and a core processor arranged on the mother board; The voltage signal connection interface is used to receive the voltage signals of each chamber, the differential voltage conversion module is used to convert the chamber voltage signal into a single-ended voltage signal with a common ground, the analog-to-digital conversion module is used to convert the single-ended voltage signal with a common ground into a voltage digital signal and then send it to the core processor, and the core processor is used to process the voltage digital signal.

9. The high-power electrolytic cell AC impedance measurement system according to claim 8, characterized in that: The differential voltage conversion module adopts a high common-mode differential voltage operational amplifier.

10. The high-power electrolytic cell AC impedance measurement system according to claim 8, characterized in that: The data acquisition device includes 6 daughter board slots and supports data acquisition of 144 channels at most.

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