Two-stage hydrogen production power supply device with self-adaptive virtual impedance adjusting function and implementation method

Abstract

The invention provides a two-stage hydrogen production power supply device with a self-adaptive virtual impedance adjusting function, which comprises a two-stage converter scheme which is composed of a three-phase voltage source type PWM (Pulse Width Modulation) rectifier and an interleaved Buck circuit and is used for providing direct-current electric energy for an electrolytic bath; the running state detection unit is used for collecting voltage, current and other parameters of the electrolytic cell and judging the running condition; corresponding virtual impedance compensation control is carried out according to the operation condition of the electrolytic cell, and the steady-state characteristic and the dynamic characteristic are improved; and the virtual impedance compensation amount of the power grid voltage is introduced for secondary adjustment so as to reduce the current and voltage fluctuation of the electrolytic cell end and improve the anti-harmonic and anti-voltage fluctuation capability of the system.

Description

Technical Field

[0001] This invention relates to the field of power conversion and power control technology, specifically to a two-stage hydrogen production power supply device and its implementation method with adaptive virtual impedance regulation function. Background Technology

[0002] With the widespread application of renewable energy in hydrogen production, water electrolysis hydrogen production systems are gradually developing towards higher power density, faster response speed, and multi-source parallel structures. Electrolyzers have high requirements for the stability of the power supply system, with particular attention to DC voltage and current ripple, disturbance response time, and constant current control accuracy. Existing projects often use a two-stage topology of "PWM rectifier + Buck" to power the electrolyzer. However, during grid fluctuations, sudden changes in electrolyzer load, or system start-up and shutdown switching, the output voltage or current is prone to large transient deviations. Simultaneously, traditional PI control does not fully consider the nonlinearity and parameter changes of the electrolyzer, increasing steady-state error and the risk of overvoltage / undercurrent. Faced with grid harmonics, voltage dips, and internal disturbances, traditional control strategies lack robustness and struggle to simultaneously meet the needs of multi-module parallel collaboration and modular expansion.

[0003] To improve system impedance characteristics, existing techniques have proposed introducing series / parallel virtual impedances on the source or load side. Series virtual impedance on the source side can improve stability but may lead to a decrease in output amplitude; parallel virtual impedance on the source side helps suppress high-frequency disturbances but complicates gain design; virtual impedance on the load side can enhance adaptability to nonlinear loads but may introduce additional voltage drops or the risk of energy backflow. Summary of the Invention

[0004] The purpose of this invention is to address the limitations of existing technologies by proposing a two-stage hydrogen production power supply device with adaptive virtual impedance regulation function.

[0005] The present invention adopts the following technical solution: A two-stage hydrogen production power supply device with adaptive virtual impedance regulation function is characterized by comprising: a two-stage converter, an electrolyzer operation status detection unit, and a control unit; the two-stage converter includes a three-phase voltage source PWM rectifier and an interleaved parallel Buck circuit, wherein the AC side of the three-phase voltage source PWM rectifier is connected to a three-phase AC power grid, and its DC side is electrically connected to the input terminal of the interleaved parallel Buck circuit, and the output terminal of the interleaved parallel Buck circuit is connected to the electrolyzer to provide DC power to the electrolyzer; wherein the interleaved parallel Buck circuit includes at least two parallel Buck power branches, and the drive signals of each parallel Buck power branch have a preset phase difference to achieve interleaved operation; The electrolytic cell operation status detection unit is used to collect the electrolytic cell terminal voltage, electrolytic cell current, and AC power grid voltage and current, and output detection signals; The control unit is used to determine the operating condition of the electrolytic cell based on the detection signal, and generate a virtual impedance compensation amount based on the operating condition. The virtual impedance compensation amount is then superimposed and injected into the current loop setpoint of the interleaved parallel Buck circuit to adjust the equivalent output impedance of the electrolytic cell and suppress voltage and current fluctuations at the electrolytic cell.

[0006] Preferably, the control unit is further configured to perform secondary adjustment on the virtual impedance compensation amount based on grid voltage and current information, and to superimpose the compensation amount obtained from the secondary adjustment into the current loop of the three-phase voltage source PWM rectifier to improve grid-connected operation stability.

[0007] Preferably, the electrolytic cell operation status detection unit analyzes and calculates the collected electrolytic cell terminal voltage and electrolytic cell current to obtain the electrolytic cell equivalent impedance information in real time. The equivalent impedance information includes at least the impedance amplitude and impedance phase at different frequencies. The control unit receives the electrolytic cell equivalent impedance information to determine the operating condition and adjust the parameters.

[0008] Preferably, the control unit determines whether the electrolytic cell is in the start-up stage or the electrolysis stage based on the equivalent impedance information of the electrolytic cell. When the electrolytic cell is in the start-up stage, the virtual impedance compensation amount is set to an inductive virtual impedance to compensate for the capacitive equivalent load and improve the equivalent damping. When the electrolytic cell is in the electrolysis stage, the virtual impedance compensation amount is set to an inductive virtual impedance, and the inductive virtual impedance parameter is adaptively tuned according to the amplitude of the equivalent impedance of the electrolytic cell to suppress load disturbances caused by changes in electrolyte concentration, pressure fluctuations in the cell, and electrode aging, and to reduce output voltage and current fluctuations.

[0009] Preferably, the control unit performs Fourier transform on the grid voltage sampling signal and performs positive-sequence, negative-sequence, and zero-sequence component analysis to obtain characteristic quantities of grid voltage harmonics, fluctuations, and imbalances; the control unit determines the secondary regulation quantity in combination with the grid-side current and superimposes the secondary regulation quantity into the current loop of the three-phase voltage source PWM rectifier to suppress grid-side current distortion caused by grid voltage fluctuations and harmonics.

[0010] Preferably, a method for implementing a two-stage hydrogen production power supply with adaptive virtual impedance regulation based on the aforementioned device is characterized by comprising the following steps: Step 110: Sampling and Preprocessing During each control cycle, the operation status detection unit synchronously samples the electrolytic cell terminal voltage, electrolytic cell current, and grid voltage and current; Step 120: Electrolytic cell impedance characteristic analysis: The expression for the electrolytic cell impedance is obtained from the k frequency phasors obtained by the operation status detection unit, and then the amplitude and phase of the electrolytic cell impedance are obtained. When the phase of the electrolytic cell impedance is less than a preset threshold, the electrolytic cell is determined to be capacitive and the electrolytic cell is in the start-up stage; otherwise, the electrolytic cell enters the electrolytic cell stage. The operation status detection unit transmits the obtained data information to the control unit. Step 130 Generation and injection of virtual impedance compensation for interleaved parallel Buck circuits: Startup phase: Set the virtual impedance to the inductive virtual impedance Z. ved (s)=sL vqd Where s is the Laplace operator, L vqd This is a virtual inductance value for the startup phase;

[0011] Where k Lqd It is the startup stage coefficient, which is related to the AC component of the output current. The larger the AC component, the higher the coefficient. lqd The larger Z is edq The impedance of the electrolytic cell during the startup phase is ω, and the frequency of the detection signal is ω. Electrolysis stage: Set the virtual impedance to the inductive-resistive virtual impedance Z. vel (s)=R vel +sL vel , where R ved This represents the real part of the virtual impedance during the startup phase. ; ; Where k Rel k Lel This is the electrolysis stage coefficient, determined based on the impedance phase of the electrolytic cell. ω represents the impedance of the electrolytic cell during the electrolysis stage, and ω is the frequency of the detection signal. Startup phase i comp =U o / Z ved Electrolysis stage i comp =U o / Z vel , Convert the virtual impedance into the compensation amount i of the current loop. comp The final current reference for the interleaved parallel Buck circuit is: ;where i base Provide a current for the current loop of the interleaved parallel Buck circuit without virtual impedance control; Step 140: Power Grid Voltage Acquisition and Analysis The control unit performs a Fourier transform on the grid voltage to obtain the harmonic spectrum and form harmonic characterization quantities; at the same time, it decomposes the grid voltage into positive sequence, negative sequence and zero sequence components to obtain the unbalance degree. Step 150: Secondary compensation injection on the PWM rectifier side: A grid disturbance index function is constructed based on harmonic characterization and unbalance. The secondary compensation amount of the current of the three-phase voltage source PWM rectifier is obtained based on the grid disturbance index function. The given value of the inner loop current of the three-phase voltage source PWM rectifier is obtained based on the secondary compensation amount.

[0012] The beneficial effects achieved by this invention are: This invention addresses the problem of output fluctuation caused by significant changes in impedance characteristics during different stages of electrolyzer startup / electrolysis, as well as the problem of grid current distortion caused by AC grid voltage harmonics, fluctuations, and imbalances, thereby improving the steady-state output accuracy, dynamic response speed, and power quality of hydrogen production power sources.

[0013] To further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are for reference and illustration only and are not intended to limit the present invention. Attached Figure Description

[0014] Figure 1 Implementation steps for a hydrogen production power source with adaptive virtual impedance Figure 2 A two-stage hydrogen production power supply topology consisting of a three-phase voltage source PWM rectifier and an interleaved parallel Buck circuit; Figure 3 The control block diagram for adaptive virtual impedance compensation; Figure 4 The waveforms of the electrolytic cell terminal voltage and current without the addition of virtual impedance compensation. Figure 5 The voltage and current waveforms of the electrolytic cell with added virtual impedance compensation; Figure 6 The waveform of phase A current under a harmonic-rich grid voltage, without the addition of virtual impedance compensation for secondary regulation; Figure 7 The waveform of phase A current under fluctuating grid voltage without the addition of virtual impedance compensation for secondary regulation; Figure 8 The waveform of phase A current under unbalanced voltage is the virtual impedance compensation without secondary adjustment. Figure 9 The waveform of phase A current under fluctuating grid voltage, with virtual impedance compensation for secondary regulation added. Detailed Implementation

[0015] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the spirit of the present invention. Furthermore, the accompanying drawings of the present invention are for simple illustrative purposes only and are not depictions of actual dimensions; this is stated in advance. The following embodiments will further describe the relevant technical content of the present invention in detail, but the disclosed content is not intended to limit the scope of protection of the present invention.

[0016] Example 1: As Figure 2 As shown, this application proposes a two-stage hydrogen production power supply device with adaptive virtual impedance regulation function, characterized in that it includes: a two-stage converter, an electrolyzer operating status detection unit, and a control unit; as shown... Figure 2 As shown, the two-stage converter includes a three-phase voltage source PWM rectifier (…). Figure 2 The dashed box on the left) and the interleaved parallel Buck circuit ( Figure 2 (The area within the dashed box on the right) The AC side of the three-phase voltage source PWM rectifier is used to connect to the three-phase AC power grid, and its DC side is electrically connected to the input terminal of the interleaved parallel Buck circuit. The output terminal of the interleaved parallel Buck circuit is used to connect to the electrolytic cell to provide DC power to the electrolytic cell. The interleaved parallel Buck circuit includes at least two parallel Buck power branches, and the drive signals of each parallel power branch have a preset phase difference to achieve interleaved operation. S1-S8 are switching transistors. dc The voltage across the capacitor on the DC side of the PWM rectifier is represented by D1 and D2, both of which are diodes. o1 L o2 Both are inductors, C i、 C o All are capacitors, i o u o These represent the current and voltage at the electrolytic cell terminals, respectively.

[0017] The electrolytic cell operation status detection unit is used to collect the electrolytic cell terminal voltage and electrolytic cell current, as well as the grid voltage and grid-side current, and output detection signals; The control unit is used to determine the operating condition of the electrolytic cell based on the detection signal, generate a virtual impedance compensation amount, and superimpose the virtual impedance compensation amount into the current loop setpoint of the interleaved parallel Buck circuit to adjust the equivalent output impedance of the electrolytic cell and suppress voltage and current fluctuations at the electrolytic cell. Furthermore, the control unit is also used to perform a secondary adjustment on the virtual impedance compensation amount based on grid voltage and grid-side current information, and superimpose the compensation amount obtained from the secondary adjustment into the current loop of the three-phase voltage source PWM rectifier to improve grid-connected operation stability. The primary adjustment by the control unit is on the load side, as shown in the attached diagram. Figure 2 i of the electrolytic cell o and u o Secondary regulation regulates the grid side, i.e., the grid voltage and current (before the inductor).

[0018] Preferably, the electrolytic cell operation status detection unit analyzes and calculates the collected electrolytic cell terminal voltage and electrolytic cell current to obtain the electrolytic cell equivalent impedance information in real time. The equivalent impedance information includes at least the impedance amplitude and impedance characteristics at different frequencies. The control unit receives the electrolytic cell equivalent impedance information to determine the operating condition and adjust the parameters.

[0019] Preferably, the control unit determines whether the electrolytic cell is in the start-up stage or the electrolysis stage based on the equivalent impedance information of the electrolytic cell. When the electrolytic cell is in the start-up stage, the virtual impedance compensation amount is set to an inductive virtual impedance to compensate for the capacitive equivalent load and improve the equivalent damping. When the electrolytic cell is in the electrolysis stage, the virtual impedance compensation amount is set to an inductive virtual impedance, and the inductive virtual impedance parameter is adaptively tuned according to the amplitude of the equivalent impedance of the electrolytic cell to suppress load disturbances caused by changes in electrolyte concentration, pressure fluctuations in the cell, and electrode aging, and to reduce output voltage and current fluctuations.

[0020] Preferably, the control unit performs Fourier transform on the grid voltage sampling signal and performs positive-sequence, negative-sequence, and zero-sequence component analysis to obtain characteristic quantities of grid voltage harmonics, fluctuations, and imbalances; the control unit determines the secondary regulation quantity in combination with the grid-side current and superimposes the secondary regulation quantity into the current loop of the three-phase voltage source PWM rectifier to suppress grid-side current distortion caused by grid voltage fluctuations and harmonics.

[0021] (1) Two-stage converter topology and interleaved parallel output structure: The device adopts a two-stage converter power supply scheme. The front stage is a three-phase voltage source type PWM rectifier, which is used to realize AC side energy conversion and DC bus voltage regulation; the rear stage is an interleaved parallel Buck circuit, which is used to convert DC bus power into adjustable DC output that meets the requirements of the electrolytic cell. The interleaved parallel Buck circuit includes at least two parallel Buck power branches. Each parallel branch works interleaved according to a preset phase difference under the drive of the control unit, so as to reduce output current ripple, reduce filter volume and increase power density, and adapt to the power supply requirements of high current and low ripple of the electrolytic cell.

[0022] (2) Electrolytic Cell Operating Status Detection and Online Impedance Identification: An electrolytic cell operating status detection unit is set up to collect the electrolytic cell terminal voltage and electrolytic cell current, and analyze and calculate the sampled signals to obtain the electrolytic cell equivalent impedance information in real time. The equivalent impedance information includes at least the impedance amplitude and impedance characteristics at different frequencies, which are used to characterize the capacitive characteristics of the electrolytic cell during the start-up stage and the capacitive-resistive characteristics during the electrolysis stage. The detection unit transmits the impedance information to the control unit to provide a basis for operating condition judgment, virtual impedance parameter setting and adaptive tuning, thereby realizing real-time tracking of changes in the load characteristics of the electrolytic cell.

[0023] (3) Virtual impedance compensation control and output impedance shaping based on operating condition determination: The control unit determines the operating condition of the electrolytic cell based on the detection signal and equivalent impedance information output by the operating status detection unit, generates a virtual impedance compensation amount corresponding to the operating condition, and injects the virtual impedance compensation amount into the current loop setpoint of the interleaved parallel Buck circuit to realize online shaping and damping injection of the equivalent output impedance at the electrolytic cell end, thereby suppressing voltage and current fluctuations at the electrolytic cell end and reducing the impact of load disturbances on the output. Further, when the electrolytic cell is in the start-up stage and the equivalent load is capacitive, an inductive virtual impedance is set to improve the equivalent damping of the system and accelerate the establishment of the voltage at the electrolytic cell end; when the electrolytic cell is in the electrolysis stage and the equivalent load is capacitive, an inductive virtual impedance is set, and the parameters of the inductive virtual impedance are adaptively tuned according to the amplitude of the equivalent impedance of the electrolytic cell to resist load disturbances caused by changes in electrolyte concentration, pressure fluctuations in the cell, and electrode aging, thereby reducing the output voltage, current ripple, and offset caused by these disturbances.

[0024] (4) Virtual Impedance Secondary Adjustment and Grid-Connected Current Shaping Based on AC-Side Grid Quality Assessment: To enhance the system's adaptability to grid disturbances, the control unit performs Fourier transform on the AC-side grid voltage sampling signal and executes positive-sequence, negative-sequence, and zero-sequence component analysis to obtain characterization quantities of grid voltage harmonics, fluctuations, and imbalances, thereby achieving assessment of grid voltage quality and disturbance determination. Based on this, the control unit determines the secondary adjustment quantity of the virtual impedance compensation quantity in conjunction with the grid-side current detection results, and superimposes the secondary adjustment quantity into the current loop of the three-phase voltage source PWM rectifier, so that the rectifier can still maintain the controllability and low distortion characteristics of the grid-side current under grid voltage fluctuations, harmonics, or imbalances, thereby suppressing grid-side current distortion caused by grid voltage disturbances and improving grid-connected operation stability and anti-disturbance performance.

[0025] Example 2: This example should be understood as including all the features of any of the foregoing examples, and further improving upon them.

[0026] The two-stage hydrogen production power supply device in this embodiment includes a three-phase voltage source PWM rectifier, an interleaved parallel Buck circuit, an electrolyzer operating status detection unit, and an MCU control unit. The MCU synchronously samples the electrolyzer terminal voltage u via an ADC. o Electrolytic cell current i o AC side power grid three-phase voltage V abc and grid-side three-phase current i abc And within a fixed control cycle, it completes impedance identification, operating condition determination, virtual impedance compensation, and secondary adjustment control. For example... Figure 1 , Figure 3 As shown, this embodiment includes steps 110 to 150, wherein steps 120-130 are primary adjustments and steps 140-150 are secondary adjustments.

[0027] Step 110: Sampling and Preprocessing Within each control cycle, the operation status detection unit detects (u) o i o u a u b u c i a i b i c Synchronous sampling is performed for electrolytic cell impedance characteristic analysis. The control period is Ts, the sliding window length is N points, and the sampling frequency is fs = 1 / Ts. The operating status detection unit synchronously samples the initial voltage value u at point n. o [n], initial current value i o [n], Phase a voltage u a [n], phase b voltage u b [n], c-phase voltage u c[n], a-phase current i a [n], phase b current i b [n], c-phase current i c [n], for further analysis, the preferred values ​​are Fs=10000Hz and N=3333. Step 120: Electrolyzer Impedance Characteristic Analysis The data information obtained by the detection unit consists of k frequency point phasors. (1) Where k = 0, 1, ..., N-1; U o is u o The constant after Fourier transform, I o is i o The constant after Fourier transform, U x is u x The constant after Fourier transform, I x is i x The constant after Fourier transform;

[0028] The expression for the impedance of the electrolytic cell is as follows: (2) Z e (ω k The impedance Z of the electrolytic cell at the detection signal frequency ω is... e The kth frequency point of (ω).

[0029] Its amplitude and phase can be obtained: (3) (4) Working condition judgment, when ∠Z e (ω k If θo < -θo, the electrolytic cell is considered capacitive, indicating it is in the startup phase; otherwise, it enters the electrolytic cell phase. Here, θo is the actual impedance angle of the electrolytic cell, determined by its impedance. ωk is the frequency of the positive and negative sequence disturbances emitted by the control unit acting on the electrolytic cell; the impedance at different frequencies is calculated using the cell's current response.

[0030] The detection unit then transmits the aforementioned data information to the control unit.

[0031] Step 130: Generation and Injection of Virtual Impedance Compensation for Interleaved Parallel Buck Circuits The control unit generates a virtual impedance compensation amount based on the electrolytic cell operating condition information from the detection unit. Startup phase: Set the virtual impedance to an inductive virtual impedance Zved(s) = sL vqd Where s is the Laplace operator, Lvqd This is a virtual inductance value for the startup phase; (10)

[0032] Where k Lqd It is the startup stage coefficient, which is related to the AC component of the output current. The larger the AC component, the higher the coefficient. lqd The larger Z is edq The impedance of the electrolytic cell during the startup phase is ω, and the frequency of the detection signal is ω. Electrolysis stage: Set the virtual impedance to the inductive-resistive virtual impedance Z. vel (s)=R vel +sL vel , where R ved This represents the real part of the virtual impedance during the startup phase. (5); (6); Where k Rel k Lel k is the coefficient for the electrolysis stage. rel =cos ∠Z e (ω k ), k Lel =sin∠Z e (ω k Z eel ω represents the impedance of the electrolytic cell during the electrolysis stage, and ω is the frequency of the detection signal. Startup phase i comp =U o / Z ved Electrolysis stage i comp =U o / Z vel , Convert the virtual impedance into the compensation amount i of the current loop. comp The final current reference for the interleaved parallel Buck side is... (7); where i base Provide a current for the current loop of the interleaved parallel Buck circuit without virtual impedance control; Step 140: Power Grid Voltage Acquisition and Analysis Control unit for u a , u b , u c Perform a Fourier transform to obtain the harmonic spectrum and form the harmonic characterization quantity (harmonic amplitude U). h Harmonic content THDu); and at the same time, for u a , u b , u cThe positive-sequence, negative-sequence, and zero-sequence components are decomposed to obtain the unbalance characterization quantity, and the fluctuation characterization quantity is obtained by combining the voltage amplitude change rate.

[0033] For u a , u b , u c By performing an FFT, the harmonic amplitude U can be obtained. h Harmonic content THDu 。

[0034] (8) Where THDu is the input voltage harmonic THD, and U1 is the fundamental voltage amplitude; Voltage fluctuations can be expressed as (9) U 1, ref For the rated input voltage amplitude (e.g., 380V), U 1,flo For the fluctuating voltage value (380 + 1% fluctuation), u a、 u b、 u c The positive, negative, and zero order components are: U a、 u b、 u c The positive, negative, and zero order components are: (11) U + For positive order components, U - U0 is the negative sequence component, and U0 is the zero sequence component. Imbalance degree is (12) Step 150: PWM rectifier side secondary compensation injection Constructing the power grid disturbance index function (13) Where φ1, φ2, and φ3 are weighting coefficients. When only one type of disturbance occurs, such as a harmonic disturbance, φ1=1, and φ2 and φ3 are all equal to 0. When two types of disturbances occur, such as harmonic and unbalanced disturbances, φ1=φ2=0.5 and φ3=0 are first set, and the corresponding virtual impedance compensation is calculated. Then, the gap is calculated in conjunction with the given compensation amount. Finally, the values ​​of φ1 and φ2 are adjusted. The given compensation amount is obtained by phasor calculation of the current after disturbance and the standard sinusoidal current. The adjustment coefficient can be expressed as: (14) k go For k g The initial value can be set according to actual needs; 1 is an option. Obtain secondary compensation amount (15) The setpoint for the inner current loop on the PWM side is... (16) Where i d0 i q0 These are the given values ​​for the d current loop (current amplitude) and q current loop (current phase) without virtual compensation control.

[0035] In this embodiment, the PWM rectifier side is a three-phase voltage source type PWM rectifier.

[0036] in, Figure 4 The electrolytic cell terminal voltage u without adding virtual impedance compensation. o and current i o Waveform, with the horizontal axis representing time t; Figure 5 For the electrolytic cell voltage u with added virtual impedance compensation o and current i o The waveforms show the electrolytic cell voltage u after adding virtual impedance compensation. o and current i o The waveform is smoother; Figure 6 The virtual impedance compensation without secondary regulation is the phase A current i under a harmonic-rich grid voltage. a Waveform, with the horizontal axis representing time t; Figure 7 The virtual impedance compensation without secondary regulation is the phase A current i under fluctuating grid voltage. a Waveform; Figure 8 The virtual impedance compensation amount without secondary regulation is the phase A current i under unbalanced voltage. a Waveform; Figure 9 The A-phase current i under grid voltage fluctuations is used to add virtual impedance compensation for secondary regulation. a The waveforms, when compared, show that the A-phase current waveform with the virtual impedance compensation added for secondary adjustment is more stable under fluctuating grid voltage.

[0037] The content disclosed above is only a preferred and feasible embodiment of the present invention, and is not intended to limit the scope of protection of the present invention. Therefore, all equivalent technical changes made based on the content of the present invention specification and drawings are included within the scope of protection of the present invention. Furthermore, the elements therein can be updated as technology develops.

Claims

1. A two-stage hydrogen production power supply device with adaptive virtual impedance regulation function, characterized in that, include: The system comprises a two-stage converter, an electrolytic cell operation status detection unit, and a control unit. The two-stage converter includes a three-phase voltage source PWM rectifier and an interleaved parallel Buck circuit. The AC side of the three-phase voltage source PWM rectifier is connected to a three-phase AC power grid, and its DC side is electrically connected to the input terminal of the interleaved parallel Buck circuit. The output terminal of the interleaved parallel Buck circuit is connected to the electrolytic cell to provide DC power to the electrolytic cell. The interleaved parallel Buck circuit includes at least two parallel Buck power branches, and the drive signals of each parallel Buck power branch have a preset phase difference to achieve interleaved operation. The electrolytic cell operation status detection unit is used to collect the electrolytic cell terminal voltage, electrolytic cell current, and grid voltage and current, and output detection signals; The control unit is used to determine the operating condition of the electrolytic cell based on the detection signal, and generate a virtual impedance compensation amount based on the operating condition. The virtual impedance compensation amount is then superimposed and injected into the current loop setpoint of the interleaved parallel Buck circuit to adjust the equivalent output impedance of the electrolytic cell and suppress voltage and current fluctuations at the electrolytic cell.

2. The two-stage hydrogen production power supply device with adaptive virtual impedance regulation function as described in claim 1, characterized in that, The control unit is also used to perform secondary adjustment of the virtual impedance compensation amount based on grid voltage and current information, and to superimpose the compensation amount obtained from the secondary adjustment into the current loop of the three-phase voltage source PWM rectifier to improve grid-connected operation stability.

3. The two-stage hydrogen production power supply device with adaptive virtual impedance regulation function as described in claim 2, characterized in that, The electrolytic cell operation status detection unit analyzes and calculates the collected electrolytic cell terminal voltage and electrolytic cell current to obtain the electrolytic cell equivalent impedance information in real time. The equivalent impedance information includes at least the impedance amplitude and impedance phase at different frequencies. The control unit receives the electrolytic cell equivalent impedance information to determine the operating condition and adjust the parameters.

4. The two-stage hydrogen production power supply device with adaptive virtual impedance regulation function as described in claim 3, characterized in that, The control unit determines whether the electrolytic cell is in the start-up stage or the electrolysis stage based on the equivalent impedance information of the electrolytic cell. When the electrolytic cell is in the start-up stage, the virtual impedance compensation amount is set to inductive virtual impedance to compensate for the capacitive equivalent load and improve the equivalent damping. When the electrolytic cell is in the electrolysis stage, the virtual impedance compensation amount is set to resistive virtual impedance, and the resistive virtual impedance parameter is adaptively tuned according to the amplitude of the equivalent impedance of the electrolytic cell to suppress load disturbances caused by changes in electrolyte concentration, pressure fluctuations in the cell, and electrode aging, and to reduce output voltage and current fluctuations.

5. The two-stage hydrogen production power supply device with adaptive virtual impedance regulation function as described in claim 4, characterized in that, The control unit performs Fourier transform on the grid voltage sampling signal and performs positive-sequence, negative-sequence, and zero-sequence component analysis to obtain characteristic quantities of grid voltage harmonics, fluctuations, and imbalances. The control unit determines the secondary regulation quantity in combination with the grid-side current and superimposes the secondary regulation quantity into the current loop of the three-phase voltage source PWM rectifier to suppress grid-side current distortion caused by grid voltage fluctuations and harmonics.

6. A method for implementing a two-stage hydrogen production power supply with adaptive virtual impedance regulation based on the aforementioned device, characterized in that, Based on the two-stage hydrogen production power supply device with adaptive virtual impedance regulation function as described in claim 5, the method includes the following steps: Step 110: Sampling and Preprocessing: During each control cycle, the operation status detection unit synchronously samples the electrolytic cell terminal voltage, electrolytic cell current, and grid voltage and current; Step 120: Electrolytic cell impedance characteristic analysis: The expression for the electrolytic cell impedance is obtained from the k frequency phasors obtained by the operation status detection unit, and then the amplitude and phase of the electrolytic cell impedance are obtained. When the phase of the electrolytic cell impedance is less than a preset threshold, the electrolytic cell is determined to be capacitive and the electrolytic cell is in the start-up stage; otherwise, the electrolytic cell enters the electrolytic cell stage. The operation status detection unit transmits the obtained data information to the control unit. Step 130 Generation and injection of virtual impedance compensation for interleaved parallel Buck circuits: Startup phase: Set the virtual impedance to the inductive virtual impedance Z. ved (s)=sL vqd Where s is the Laplace operator, L vqd This is a virtual inductance value for the startup phase; Where k Lqd It is the startup stage coefficient, which is related to the AC component of the output current. The larger the AC component, the higher the coefficient. lqd The larger Z is edq The impedance of the electrolytic cell during the startup phase is ω, and the frequency of the detection signal is ω. Electrolysis stage: Set the virtual impedance to the inductive-resistive virtual impedance Z. vel (s)=R vel +sL vel , where R ved This represents the real part of the virtual impedance during the startup phase. ； ； Where k Rel k Lel This is the electrolysis stage coefficient, determined based on the impedance phase of the electrolytic cell. ω represents the impedance of the electrolytic cell during the electrolysis stage, and ω is the frequency of the detection signal. Startup phase i comp =U o / Z ved Electrolysis stage i comp =U o / Z vel , Convert the virtual impedance into the compensation amount i of the current loop. comp The final current reference for the interleaved parallel Buck circuit is... ;where i base Provide a current for the current loop of the interleaved parallel Buck circuit without virtual impedance control; Step 140: Power Grid Voltage Acquisition and Analysis The control unit performs a Fourier transform on the grid voltage to obtain the harmonic spectrum and form harmonic characterization quantities; at the same time, it decomposes the grid voltage into positive sequence, negative sequence and zero sequence components to obtain the unbalance degree. Step 150: Secondary compensation injection on the PWM rectifier side: A grid disturbance index function is constructed based on harmonic characterization and unbalance. The secondary compensation amount of the current of the three-phase voltage source PWM rectifier is obtained based on the grid disturbance index function. The given value of the inner loop current of the three-phase voltage source PWM rectifier is obtained based on the secondary compensation amount.

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