Hybrid electrolytic cell networking control method based on adaptive parameter adjustment

Abstract

The invention discloses a hybrid electrolytic cell networking control method based on adaptive parameter adjustment, and the method comprises the steps: enabling a distributed photovoltaic system to operate in a maximum power point tracking mode, and constructing a collaborative networking topological structure in which an alkali liquor electrolytic hydrogen production load and a proton exchange membrane electrolytic hydrogen production load interact with a source side through a converter; whether the absolute value of the frequency fluctuation deviation is smaller than a preset frequency adjustment dead zone or not is judged, if yes, frequency supporting is conducted on the mixed electrolytic cell through a synchronous control method based on the direct-current voltage dynamic state, and the voltage amplitude is controlled through Q-U droop; on the contrary, active-frequency control is added to the hydrogen production load side converter, and control parameters are adaptively adjusted according to frequency dynamic characteristics, so that the power of the proton exchange membrane hydrogen production load and the power of the alkali liquor hydrogen production load are reasonably distributed when the system frequency fluctuates. The photovoltaic utilization rate can be improved to the maximum extent, and different types of electrolytic cells on the hydrogen production load side are used for network construction control so as to guarantee system stability.

Description

Technical Field

[0001] This invention relates to the field of novel power system converter control technology, and in particular to a hybrid electrolytic cell grid control method based on adaptive parameter adjustment. Background Technology

[0002] With the increasing global demand for clean energy, combining distributed photovoltaic power generation with water electrolysis to produce "green hydrogen" has become an important direction for achieving energy transition.

[0003] However, with the increasing penetration of new energy sources, the inertia and frequency regulation capabilities of power systems are declining. Electrolysis-based hydrogen production loads, as controllable flexible loads, can participate in frequency support through rapid power response. However, single-type electrolyzers have limitations: proton exchange membrane (PEM) electrolyzers have fast response speeds and wide adjustment ranges, but are more expensive; alkaline liquid (ALK) electrolyzers are cheaper but have slower response times. Existing technologies have not fully explored the synergistic potential of hybrid electrolyzers, and fixed control parameters are difficult to adapt to the nonlinear characteristics of deviations and rates of change during dynamic frequency variations in the system, resulting in low utilization of regulation capabilities and poor economic efficiency.

[0004] Therefore, designing a grid control method that can adaptively adjust control parameters based on frequency dynamic characteristics and synergistically leverage the advantages of different types of electrolytic cells has become a key issue in improving the frequency stability of new power systems. Summary of the Invention

[0005] The purpose of this invention is to address the problems of inflexible frequency support and poor control performance caused by fixed control parameter adjustment in existing technologies using a single electrolyzer, and to provide a hybrid electrolyzer network control method based on adaptive parameter adjustment. This invention enables coordinated frequency regulation of different types of electrolyzers, improves system frequency stability and dynamic response capabilities, and is suitable for the stable operation of high-proportion renewable energy power systems.

[0006] The objective of this invention is achieved through the following technical solution: a hybrid electrolyzer network control method based on adaptive parameter adjustment, wherein the hybrid electrolyzer includes an alkaline electrolyzer and a proton exchange membrane electrolyzer; the method specifically includes: Distributed photovoltaic power generation operates in maximum power point tracking mode, constructing a collaborative grid topology where alkaline electrolysis hydrogen production load and proton exchange membrane electrolysis hydrogen production load interact with the source side through converters; The system determines whether the absolute value of the frequency fluctuation deviation is less than the preset frequency adjustment dead zone. If the absolute value of the frequency fluctuation deviation is less than the preset frequency adjustment dead zone, the hybrid electrolyzer adopts a synchronous control method based on DC voltage dynamics for frequency support and uses QU droop control voltage amplitude. Otherwise, active power-frequency control is added to the converter on the hydrogen production load side, and the control parameters are adaptively adjusted according to the frequency dynamic characteristics to reasonably allocate the power of the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load when the system frequency fluctuates.

[0007] Furthermore, the distributed photovoltaic system has a two-stage structure. The front-stage DC-DC converter ensures a constant output voltage for the DC-side photovoltaic array, while the rear-stage DC-AC converter enables maximum power point tracking of the photovoltaic system. A phase-locked loop (PLL) synchronizes the DC-AC converter with the power grid.

[0008] Furthermore, all the hybrid electrolytic cells are controlled by active power and frequency through a DC-DC converter, and then connected to the AC system by a DC-AC converter based on dynamic DC voltage synchronization control.

[0009] Furthermore, the frequency fluctuation deviation is obtained by the following method: Measure the actual value of the system frequency and calculate the difference between it and the system frequency rating as the frequency fluctuation deviation.

[0010] Furthermore, the hybrid electrolytic cell employs a frequency-supported synchronous control method based on dynamic DC voltage, and uses QU droop control to adjust the voltage amplitude, specifically including: The hydrogen production load control equations for proton exchange membrane electrolyzers and alkaline electrolyzers have the same form. The hydrogen production load control equation for a proton exchange membrane electrolyzer is:

[0011]

[0012] In the formula, This is the actual value of the angular frequency. This is the rated value of the angular frequency; and These are the actual and rated values ​​of the DC bus voltage on the electrolytic cell side, respectively. This is the AC voltage reference value. This is the rated AC voltage. and These are the reference and actual values ​​of reactive power absorbed by the grid-side converter of the electrolytic cell, respectively. For the Laplace operator, , , , These are the differential coefficient, integral coefficient, damping coefficient, and gain coefficient in synchronous control based on DC voltage dynamics. This is the QU droop coefficient.

[0013] Furthermore, the addition of active-frequency control to the converter on the hydrogen production load side, adaptively adjusting control parameters based on frequency dynamic characteristics to rationally allocate power between the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load when system frequency fluctuates, specifically includes: Active-frequency control is added to the converters on the proton exchange membrane hydrogen production load side and the alkaline solution hydrogen production load side. When system frequency fluctuations occur, the control reference values ​​for the proton exchange membrane hydrogen production load power and the alkaline solution hydrogen production load power are determined based on the frequency fluctuation deviation through active-frequency control. The control equation is as follows:

[0014]

[0015] In the formula, This serves as a reference value for controlling the load power of proton exchange membrane hydrogen production. The power setpoint for hydrogen production loading via proton exchange membranes; This is a reference value for controlling the load power of alkaline solution hydrogen production. The power setpoint for the alkaline solution hydrogen production load; This is due to frequency fluctuation deviation; For the Laplace operator; and These are the active-frequency droop coefficients corresponding to the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load, respectively. and These are the virtual inertia coefficients corresponding to the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load, respectively. The active-frequency droop coefficient and the virtual inertia coefficient are adaptively adjusted according to the frequency dynamic characteristics. The error between the control reference value of the proton exchange membrane or alkaline hydrogen production load power and the active power output of the corresponding transformer is input into the PI controller to obtain the corresponding current reference value. The difference between this value and the current flowing to the positive terminal of the proton exchange membrane or alkaline hydrogen production load is then sent to the PI controller to generate a modulation wave reference signal. This signal is then sent to the corresponding pulse width modulation to generate a pulse width modulation wave input to the corresponding DC-DC converter, thereby controlling the power of the proton exchange membrane or alkaline hydrogen production load.

[0016] Furthermore, the adaptive adjustment of control parameters based on frequency dynamic characteristics includes the active-frequency droop coefficients corresponding to the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load, as well as the virtual inertia coefficients corresponding to the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load. This is specifically achieved through the following method: First, the corresponding power regulation margin is calculated based on the operating power and regulation range of the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load. Then analyze the frequency dynamic characteristics, that is, the rate of frequency change. and frequency fluctuation deviation Comparison and analysis with 0 respectively: When At that time, the pseudo-inertia coefficients of the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load in the control parameters are adjusted according to the following formula:

[0017]

[0018] In the formula, and Let represent the virtual inertia coefficients of the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load at time t, respectively. This represents the scaling factor for deviation control. This represents the asymptotic value of the virtual inertia coefficient. and These represent the power regulation margins at time t for the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load, respectively. and These represent the minimum power adjustment margins for proton exchange membrane hydrogen production load and alkaline solution hydrogen production load, respectively. when At that time, the pseudo-inertia coefficients of the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load in the control parameters are adjusted according to the following formula:

[0019]

[0020] In the formula, and These represent the maximum power adjustment margins for proton exchange membrane hydrogen production load and alkaline solution hydrogen production load, respectively. when At that time, the active-frequency droop coefficients of the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load in the control parameters are adjusted according to the following formula:

[0021]

[0022] when At that time, the active-frequency droop coefficients of the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load in the control parameters are adjusted according to the following formula:

[0023]

[0024] In the formula, and Let represent the active-frequency droop coefficients of the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load at time t, respectively. This indicates the scaling factor controlling the rate of change. This represents the asymptotic value of the active-frequency droop coefficient.

[0025] The beneficial effects of this invention are as follows: It employs a hybrid electrolytic cell for network control, fully leveraging the synergistic advantages of the hybrid electrolytic cells to improve the system's dynamic response capability; through an adaptive parameter adjustment strategy, it dynamically adjusts the control parameters of the PEM and ALK electrolytic cells based on frequency deviation and rate of change, achieving coordinated frequency modulation of different types of electrolytic cells and improving system frequency stability; it designs control parameters based on a variant of the tanh function, ensuring a smooth and continuous parameter adjustment process, avoiding system oscillation problems caused by traditional fixed parameter control, and improving the robustness of the control strategy; considering the power adjustment margin of the electrolytic cells and setting the adjustment range in conjunction with safety and economic operation requirements, it ensures the feasibility and economy of the control strategy in practical applications. Attached Figure Description

[0026] Figure 1 This is a topology diagram of the hybrid electrolytic cell network control system based on adaptive parameter adjustment of the present invention; Figure 2 This is a flowchart of the hybrid electrolytic cell network control method based on adaptive parameter adjustment of the present invention; Figure 3 This is a graph of the tanh function (y=tanh(x)) of this invention. Detailed Implementation

[0027] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the invention as detailed in the appended claims.

[0028] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms “a,” “the,” and “the” used in this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0029] It should be understood that although the terms first, second, third, etc., may be used in this invention to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first information may also be referred to as second information without departing from the scope of this invention, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to a determination."

[0030] The present invention will now be described in detail with reference to the accompanying drawings. Unless otherwise specified, the features of the following embodiments and implementations can be combined with each other. See Figure 1 In the hybrid electrolyzer network control system based on adaptive parameter adjustment of the present invention, the hybrid electrolyzer participates in the system control as a flexible load. The hydrogen production system is equipped with both alkaline solution (ALK) electrolyzer and proton exchange membrane (PEM) electrolyzer, that is, the hybrid electrolyzer includes ALK electrolyzer and PEM electrolyzer.

[0031] See Figure 2 The hybrid electrolyzer grid control method based on adaptive parameter adjustment of the present invention specifically includes: First, the distributed photovoltaic system operates in maximum power point tracking (MPPT) mode, constructing a collaborative grid topology where the ALK electrolysis hydrogen production load and the PEM electrolysis hydrogen production load interact with the source side through a converter. Then, it is determined whether the absolute value of the frequency fluctuation deviation is less than a preset frequency regulation dead zone. If the absolute value of the frequency fluctuation deviation is less than the preset frequency regulation dead zone, the hybrid electrolyzer adopts a synchronous control method based on DC voltage dynamics for frequency support, using QU droop control of the voltage amplitude; otherwise, active power-frequency control is added to the converter on the hydrogen production load side, and the control parameters are adaptively adjusted according to the frequency dynamic characteristics to reasonably allocate the power of the PEM hydrogen production load and the ALK hydrogen production load when the system frequency fluctuates.

[0032] It should be noted that, to prevent frequent adjustments due to small fluctuations in system frequency, a frequency adjustment dead zone is preset. When frequency fluctuation deviation The absolute value is greater than or equal to the frequency adjustment dead zone. At that time, the hydrogen production load of the hybrid electrolyzer (i.e., PEM electrolyzer and ALK electrolyzer) begins to participate in the regulation in a coordinated manner.

[0033] In this embodiment, the distributed photovoltaic system on the source side has a two-stage structure. The front-stage DC-DC converter ensures a constant output voltage for the DC-side photovoltaic array, and the rear-stage DC-AC converter implements the MPPT (Multi-Level Photovoltaic Test) of the photovoltaic system. A phase-locked loop (PLL) synchronizes the DC-AC converter with the grid. Figure 1As shown, the distributed photovoltaic (PV) system on the source side operates in MPPT mode, reserving no power for system frequency regulation. The load side generates the corresponding response to stabilize the system frequency. In a two-stage distributed PV structure operating in MPPT mode, the source-side PV only outputs maximum power, with system stability maintained solely by the hydrogen production load. The ALK electrolysis hydrogen production load and the PEM electrolysis hydrogen production load interact with the source side through converters, collaboratively constructing the grid topology. Distributed PV connected to the grid constitutes the source side. Part of the source-side AC system power is used to meet the power demands of conventional loads, while the other part is transmitted to the electrolysis hydrogen production load through a transformer. The electrolysis hydrogen production load is directly connected to the DC-DC converter, which is connected to the DC-AC converter via a DC capacitor, and then connected to the source side via a filter unit and transformer.

[0034] like Figure 1 As shown, taking the PEM electrolysis hydrogen production load as an example, the AC voltage on the transformer output side is collected in real time. and alternating current The output active power and reactive power are respectively and The voltage across the DC capacitor between the DC-AC converter and the DC-DC converter is... The current flowing from the DC-DC converter to the positive electrode of the PEM electrolysis hydrogen production load is .

[0035] Furthermore, all hybrid electrolyzers are controlled by active power and frequency via DC-DC converters, and then connected to the AC system via DC-AC converters for synchronous control based on DC voltage dynamics.

[0036] In this embodiment, the frequency fluctuation deviation is obtained by the following method: measuring the actual value of the system frequency. Calculate the actual value of the system frequency. With system frequency rating The difference between them is taken as the frequency fluctuation deviation and expressed as:

[0037] In the formula, For frequency fluctuation deviation, This is the actual value of the system frequency. This is the system frequency rating.

[0038] In this embodiment, the hybrid electrolyzer uses a synchronous control method based on DC voltage dynamics for frequency support and employs QU droop control for voltage amplitude. Specifically, the hydrogen production load control equations for the PEM electrolyzer and the ALK electrolyzer have the same form. Here, only the hydrogen production load control equation for the PEM electrolyzer is shown, and its expression is:

[0039]

[0040] In the formula, This is the actual value of the angular frequency. This is the rated value of the angular frequency; and These are the actual and rated values ​​of the DC bus voltage on the electrolytic cell side, respectively. This is the AC voltage reference value. This is the rated AC voltage. and These are the reference and actual values ​​of reactive power absorbed by the grid-side converter of the electrolytic cell, respectively. For the Laplace operator, , , , These are the differential coefficient, integral coefficient, damping coefficient, and gain coefficient in synchronous control based on DC voltage dynamics. This is the QU droop coefficient.

[0041] Specifically, such as Figure 1 As shown, the actual value of angular frequency The actual phase angle can be obtained through integration. AC voltage reference value Combining phase angle The d-axis variable of the AC voltage reference value is obtained by performing a Park transformation. With q-axis variable The voltage and current on the output side of the transformer are and Combining phase angle Performing the Park transformation yields the d-axis and q-axis variables of the AC voltage and AC current, i.e. , and , Park transformation refers to the process of mapping three-phase time-varying AC phasors to a two-axis rotating coordinate system, transforming them into variables with d-axis, q-axis, and 0-axis coordinates. The d- and q-axis components of the AC voltage reference value and the actual d- and q-axis components are input into the AC voltage controller to obtain the d- and q-axis components of the AC current reference value. and Subsequently, the reference values ​​of the AC current along the d and q axes are compared with the actual values ​​of the AC current along the d and q axes. , The modulation reference voltage in the two-axis rotating coordinate system is obtained by AC current control. and Modulation reference voltage combined The pulse width modulation (PWM) reference signal is obtained by performing an inverse Parker transformation (reducing the variables in the two-axis rotating coordinate system to three-phase time-varying AC phasors). A 10kHz sawtooth wave is used as the carrier signal and compared with the modulation reference signal to generate the PWM wave input to the DC-AC converter. The resulting PWM wave controls the switching of the DC-AC converter's switching devices, driving the DC-AC converter to obtain the target output.

[0042] In this embodiment, active-frequency control is added to the converter on the hydrogen production load side. Control parameters are adaptively adjusted based on frequency dynamic characteristics to rationally allocate the power of the proton exchange membrane (PEM) hydrogen production load and the alkaline solution hydrogen production load when the system frequency fluctuates. Specifically, this includes: firstly, adding active-frequency control to the converters on both the PEM and ALK hydrogen production load sides so that the PEM and ALK hydrogen production loads take corresponding actions to stabilize the system frequency when it fluctuates. A control reference value for the PEM hydrogen production load power is then determined. and the control reference value of ALK hydrogen production load power Frequency fluctuations are taken into account; that is, based on the frequency fluctuation deviation, the control reference value of the PEM hydrogen production load power is determined through active power-frequency control. and the control reference value of ALK hydrogen production load power Its governing equations are as follows:

[0043]

[0044] In the formula, This is a control reference value for the hydrogen production load power of PEM. The power setpoint for the PEM hydrogen production load; This is the control reference value for the hydrogen production load power of ALK. The power setpoint for the ALK hydrogen production load; This is due to frequency fluctuation deviation; and These are the active-frequency droop coefficients corresponding to the PEM hydrogen production load and the ALK hydrogen production load, respectively. and The virtual inertia coefficients for the PEM hydrogen production load and ALK hydrogen production load are respectively, and s is the Laplace operator. The active-frequency droop coefficient and the virtual inertia coefficient are adaptively adjusted according to the frequency dynamic characteristics. Subsequently, the active-frequency control on the PEM hydrogen production load side is used as an example for explanation, and the control reference value of the PEM hydrogen production load power is... and the active power output of the corresponding transformer The error between the inputs is fed into the PI controller to obtain the current reference value for the PEM hydrogen production load. Reference value of current for PEM hydrogen production load. The current flowing from the DC-DC converter to the positive electrode of the PEM electrolysis hydrogen production load The difference is input to the PI controller to generate a modulation wave reference signal, which is then sent to the corresponding pulse width modulator to generate a PWM wave input to the corresponding DC-DC converter to control the power of the PEM hydrogen production load. The control reference value for the ALK hydrogen production load power is then used. and the active power output of the corresponding transformer The error between the inputs is fed into the PI controller to obtain the current reference value for the ALK hydrogen production load. Reference value for the current load of alkaline solution for hydrogen production. and the current flowing from the DC-DC converter to the positive terminal of the ALK hydrogen production load. The error between the inputs is fed into the PI controller to obtain a modulation reference signal, which is then sent to the corresponding pulse width modulation (PWM) circuit to generate a PWM wave for the corresponding DC-DC converter, thereby controlling the power of the ALK hydrogen production load. The output of the PI controller is:

[0045] In the formula, This represents the output of the PI controller, i.e., the current reference value of the PEM hydrogen production load. Or modulated wave reference signal; This represents the input of the PI controller, i.e. and The error between or and The difference between them; For the Laplace operator, This represents the proportional gain of the PI controller. This represents the integral coefficient of the PI controller.

[0046] Furthermore, the control parameters are adaptively adjusted based on the frequency dynamic characteristics. These control parameters include the active-frequency droop coefficients corresponding to the PEM hydrogen production load and the ALK hydrogen production load, as well as the virtual inertia coefficients corresponding to the PEM hydrogen production load and the ALK hydrogen production load. This is achieved through the following method: First, the corresponding power regulation margin is calculated based on the operating power and regulation range of the PEM hydrogen production load and the ALK hydrogen production load. The calculation formula is as follows:

[0047]

[0048] In the formula, This represents the power regulation margin of the PEM hydrogen production load at time t. This represents the operating power of the PEM hydrogen production load at time t, and the adjustment range of the PEM hydrogen production load is... , and These represent the maximum and minimum power regulation values ​​for the PEM hydrogen production load, respectively. , , Rated power for PEM hydrogen production load; This represents the power regulation margin of the ALK hydrogen production load at time t. This represents the operating power of the ALK hydrogen production load at time t, and the adjustment range of the ALK hydrogen production load is... , and These represent the maximum and minimum power regulation values ​​for the ALK hydrogen production load. , , This represents the rated power of the ALK hydrogen production load. From the above formula for calculating the power regulation margin, it can be seen that the range of the power regulation margin is [0,1]. To ensure both safety and economy in control, the maximum power regulation margin of the PEM hydrogen production load is taken. Minimum power regulation margin of PEM hydrogen production load Maximum power regulation margin of ALK hydrogen production load Minimum power regulation margin of ALK hydrogen production load .

[0049] It should be noted that the initial deviation of the system frequency change is relatively small, but the rate of change is large; in the middle and later stages, the deviation is large while the rate of change is small. Because the PEM hydrogen production load has a fast response speed, it is preferentially utilized to participate in system frequency regulation, thus minimizing the frequency change rate. Reduce, when its regulatory capacity reaches its limit. When the load exceeds its set adjustment range, reduce the virtual inertia coefficient of the PEM hydrogen production load. Increase the virtual inertia coefficient of ALK hydrogen production load This allows for prioritizing the reduction of frequency variation rate through the PEM hydrogen production load when the PEM hydrogen production load has sufficient adjustment capability; and prioritizing the reduction of frequency fluctuation deviation through the ALK hydrogen production load. (i.e., frequency variation deviation), when its adjustment capability reaches its limit, that is... When the load exceeds its set adjustment range, reduce the active-frequency droop coefficient of the ALK hydrogen production load. Increase the active-frequency droop coefficient of PEM hydrogen production load. In this way, when the ALK hydrogen production load has sufficient adjustment capability, the frequency variation deviation can be reduced preferentially through the ALK hydrogen production load.

[0050] Subsequently, based on the above frequency dynamic characteristic analysis process, control parameters were designed based on a variant of the tanh function, and the graph of the function y=tanh(x) was obtained from... Figure 3 As shown. Figure 2 As shown, when When needed, adjust the control parameters according to the following formula:

[0051]

[0052] In the formula, and Let represent the virtual inertia coefficients of the PEM hydrogen production load and the ALK hydrogen production load at time t, respectively. This represents the scaling factor for deviation control. This represents the asymptotic value of the virtual inertia coefficient. When... When needed, adjust the control parameters according to the following formula:

[0053]

[0054] when When needed, adjust the control parameters according to the following formula:

[0055]

[0056] In the formula, and Let represent the active-frequency droop coefficients of the PEM hydrogen production load and the ALK hydrogen production load at time t, respectively. This indicates the scaling factor controlling the rate of change. This represents the asymptotic value of the active-frequency droop factor. When When needed, adjust the control parameters according to the following formula:

[0057]

[0058] Therefore, after obtaining the power regulation margins corresponding to the PEM hydrogen production load and the ALK hydrogen production load, as well as the maximum and minimum values ​​of each power regulation margin, the frequency dynamic characteristics, i.e., the frequency change rate, are analyzed. and frequency fluctuation deviation Comparison and analysis with 0 respectively: When When needed, the control parameters are adjusted using the corresponding formula. and ;when When needed, the control parameters are adjusted using the corresponding formula. and This allows for prioritizing the reduction of the frequency variation rate through the PEM hydrogen production load when the power regulation capability of the PEM hydrogen production load is sufficient (i.e., the power regulation margin of the PEM hydrogen production load does not exceed its corresponding maximum and minimum power regulation margins). When needed, the control parameters are adjusted using the corresponding formula. and ;when When needed, the control parameters are adjusted using the corresponding formula. and In this way, when the power regulation capability of the ALK hydrogen production load is sufficient (i.e., the power regulation margin of the ALK hydrogen production load does not exceed its corresponding maximum and minimum power regulation margin), the frequency variation deviation can be reduced preferentially through the ALK hydrogen production load.

[0059] In summary, this invention maximizes photovoltaic utilization, utilizes different types of electrolyzers on the load side for grid control to ensure system stability, adaptively adjusts control parameters based on frequency dynamic characteristics, and rationally allocates the power regulation responsibilities of PEM hydrogen production load and ALK hydrogen production load during system frequency fluctuations. This invention has scientific significance and practical application value for the safe and economical production of large-scale green hydrogen production industries.

[0060] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling the network structure of a hybrid electrolytic cell based on adaptive parameter adjustment, characterized in that, The hybrid electrolyzer includes an alkaline electrolyzer and a proton exchange membrane electrolyzer; the method specifically includes: Distributed photovoltaic power generation operates in maximum power point tracking mode, constructing a collaborative grid topology where alkaline electrolysis hydrogen production load and proton exchange membrane electrolysis hydrogen production load interact with the source side through converters; The system determines whether the absolute value of the frequency fluctuation deviation is less than the preset frequency adjustment dead zone. If the absolute value of the frequency fluctuation deviation is less than the preset frequency adjustment dead zone, the hybrid electrolyzer adopts a synchronous control method based on DC voltage dynamics for frequency support and uses QU droop control voltage amplitude. Otherwise, active power-frequency control is added to the converter on the hydrogen production load side, and the control parameters are adaptively adjusted according to the frequency dynamic characteristics to reasonably allocate the power of the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load when the system frequency fluctuates.

2. The hybrid electrolytic cell network control method based on adaptive parameter adjustment according to claim 1, characterized in that, The distributed photovoltaic system has a two-stage structure. The front-stage DC-DC converter keeps the output voltage of the DC-side photovoltaic array constant, while the rear-stage DC-AC converter enables the photovoltaic system to achieve maximum power point tracking. The DC-AC converter is synchronized with the power grid through a phase-locked loop.

3. The hybrid electrolytic cell network control method based on adaptive parameter adjustment according to claim 1, characterized in that, The hybrid electrolyzers are all controlled by active power and frequency through a DC-DC converter, and then connected to the AC system by a DC-AC converter based on dynamic DC voltage synchronization control.

4. The hybrid electrolytic cell network control method based on adaptive parameter adjustment according to claim 1, characterized in that, The frequency fluctuation deviation is obtained through the following method: Measure the actual value of the system frequency and calculate the difference between it and the system frequency rating as the frequency fluctuation deviation.

5. The hybrid electrolytic cell network control method based on adaptive parameter adjustment according to claim 1, characterized in that, The hybrid electrolyzer employs a synchronous control method based on dynamic DC voltage for frequency support, and uses QU droop control to adjust the voltage amplitude, specifically including: The hydrogen production load control equations for proton exchange membrane electrolyzers and alkaline electrolyzers have the same form. The hydrogen production load control equation for a proton exchange membrane electrolyzer is: ； ； In the formula, This is the actual value of the angular frequency. This is the rated value of the angular frequency; and These are the actual and rated values ​​of the DC bus voltage on the electrolytic cell side, respectively. This is the AC voltage reference value. This is the rated AC voltage. and These are the reference and actual values ​​of reactive power absorbed by the grid-side converter of the electrolytic cell, respectively. For the Laplace operator, , , , These are the differential coefficient, integral coefficient, damping coefficient, and gain coefficient in synchronous control based on DC voltage dynamics. This is the QU droop coefficient.

6. The hybrid electrolytic cell network control method based on adaptive parameter adjustment according to claim 1, characterized in that, The addition of active-frequency control to the converter on the hydrogen production load side, adaptively adjusting control parameters based on frequency dynamic characteristics to rationally allocate power between the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load when the system frequency fluctuates, specifically includes: Active-frequency control is added to the converters on the proton exchange membrane hydrogen production load side and the alkaline solution hydrogen production load side. When system frequency fluctuations occur, the control reference values ​​for the proton exchange membrane hydrogen production load power and the alkaline solution hydrogen production load power are determined based on the frequency fluctuation deviation through active-frequency control. The control equation is as follows: ； ； In the formula, This serves as a reference value for controlling the load power of proton exchange membrane hydrogen production. The power setpoint for hydrogen production loading via proton exchange membranes; This is a reference value for controlling the load power of alkaline solution hydrogen production. The power setpoint for the alkaline solution hydrogen production load; This is due to frequency fluctuation deviation; For the Laplace operator; and These are the active-frequency droop coefficients corresponding to the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load, respectively. and These are the virtual inertia coefficients corresponding to the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load, respectively. The active-frequency droop coefficient and the virtual inertia coefficient are adaptively adjusted according to the frequency dynamic characteristics. The error between the control reference value of the proton exchange membrane or alkaline hydrogen production load power and the active power output of the corresponding transformer is input into the PI controller to obtain the corresponding current reference value. The difference between this value and the current flowing to the positive terminal of the proton exchange membrane or alkaline hydrogen production load is then sent to the PI controller to generate a modulation wave reference signal. This signal is then sent to the corresponding pulse width modulation to generate a pulse width modulation wave input to the corresponding DC-DC converter, thereby controlling the power of the proton exchange membrane or alkaline hydrogen production load.

7. The hybrid electrolytic cell network control method based on adaptive parameter adjustment according to claim 6, characterized in that, The adaptive adjustment of control parameters based on frequency dynamic characteristics includes the active-frequency droop coefficients corresponding to the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load, as well as the virtual inertia coefficients corresponding to the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load. This is specifically achieved through the following method: First, the corresponding power regulation margin is calculated based on the operating power and regulation range of the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load. Then analyze the frequency dynamic characteristics, that is, the rate of frequency change. and frequency fluctuation deviation Comparison and analysis with 0 respectively: When At that time, the pseudo-inertia coefficients of the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load in the control parameters are adjusted according to the following formula: ； ； In the formula, and Let represent the virtual inertia coefficients of the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load at time t, respectively. This represents the scaling factor for deviation control. This represents the asymptotic value of the virtual inertia coefficient. and These represent the power regulation margins at time t for the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load, respectively. and These represent the minimum power adjustment margins for proton exchange membrane hydrogen production load and alkaline solution hydrogen production load, respectively. when At that time, the pseudo-inertia coefficients of the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load in the control parameters are adjusted according to the following formula: ； ； In the formula, and These represent the maximum power adjustment margins for proton exchange membrane hydrogen production load and alkaline solution hydrogen production load, respectively. when At that time, the active-frequency droop coefficients of the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load in the control parameters are adjusted according to the following formula: ； ； when At that time, the active-frequency droop coefficients of the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load in the control parameters are adjusted according to the following formula: ； ； In the formula, and Let represent the active-frequency droop coefficients of the proton exchange membrane hydrogen production load and the alkaline solution hydrogen production load at time t, respectively. This indicates the scaling factor controlling the rate of change. This represents the asymptotic value of the active-frequency droop coefficient.

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