A Synchronous Control Method for Hydrogen Production by Electrolysis in ALK-PEM Based on Direct Torque and Droop Control

Abstract

This invention discloses an ALK-PEM electrolysis hydrogen production synchronous control method based on direct torque and droop control, implemented using a "DTC-adaptive droop" dual-loop collaborative control architecture, including: real-time acquisition of the total power P input from wind and solar power sources. total The absolute value of the state of charge and power change rate of the hydrogen storage system, |dP / dt|, is used to generate electrolyzer power commands. The electrolyzer includes an alkaline electrolyzer (ALK) and a proton exchange membrane electrolyzer (PEM). An adaptive droop coefficient is dynamically calculated based on the absolute value of the state of charge and power change rate of the hydrogen storage system, |dP / dt|. The electrolyzer power P of the PEM and ALK is allocated accordingly. PEM and P ALK ; P PEM and P ALK The generated instructions are input to the DTC controller, which produces PWM drive signals to drive the PEM and ALK electrolyzers respectively. The corresponding control system and a hydrogen production device including the control system are also disclosed. The hydrogen production device further includes: a PEM electrolyzer unit, an ALK electrolyzer unit, and a wind and solar power interface.

Description

Technical Field

[0001] This invention relates to the field of renewable energy hydrogen production technology, and particularly to a synchronous control method for ALK-PEM electrolysis hydrogen production based on direct torque and droop control. Specifically, it relates to a collaborative control method suitable for a hybrid hydrogen production system of alkaline electrolyzers (ALK) and proton exchange membrane electrolyzers (PEM). By integrating direct torque control (DTC) and adaptive droop control, it achieves precise power allocation, dynamic response optimization, and improved system stability for multiple electrolyzers under fluctuating wind and solar power supply. Background Technology

[0002] With the rapid development of the renewable energy hydrogen production industry, direct-drive water electrolysis hydrogen production systems powered by fluctuating power sources such as wind and solar power have become a key technological route for the industry. However, current electrolyzer control technology faces three core bottlenecks, which severely restrict hydrogen production efficiency and system economics.

[0003] First, the inherent limitations of single-cell electrolyzers make them unsuitable for adapting to the wide fluctuations in wind and solar power output. While proton exchange membrane electrolyzers (PEMs) possess millisecond-level dynamic response capabilities, their anode catalysts rely on the precious metal iridium, and their cathodes require platinum-supported carbon materials. Limited by catalyst activity and membrane mechanical strength, the current density is typically restricted to 2 A / cm². 2 Below. Under high power fluctuation scenarios, the hydrogen production efficiency of PEM (Polymer Electrolyte) significantly decreases due to increased ohmic polarization. In contrast, alkaline electrolyzers (ALK), although capable of withstanding 4A / cm... 2 While these methods offer high current densities and low costs, their reliance on alkaline electrolytes and ion migration mechanisms results in slow response times (on the order of seconds), making it impossible to track minute- or even second-level fluctuations in wind and solar power. This performance contradiction leads to an irreconcilable "efficiency-response" dilemma for single electrolyzers in fluctuating power supply scenarios.

[0004] Secondly, the coordinated control of multiple electrolyzers operating in parallel has serious flaws. To balance response speed and hydrogen production efficiency, the industry generally adopts a hybrid deployment scheme of PEM and ALK. However, traditional droop control uses a fixed power allocation coefficient. In the low power range (<30% of rated power), the PEM frequently triggers current density protection due to bearing the main load, while the ALK remains idle for a long time due to the start-up threshold limitation. In the high power range (>80% of rated power), the ALK enters a saturation state due to response lag, and the rapid adjustment capability of the PEM is not fully utilized. For example, Chinese patent application CN112117637A attempts to introduce PID coordinated control to optimize power allocation, but its linear control mechanism causes system oscillations during power surges, resulting in DC bus voltage fluctuations exceeding the limit of ±10%, further aggravating electrode corrosion in the electrolyzers.

[0005] More seriously, control failures directly lead to systemic efficiency losses. A 2023 report by the International Energy Agency (IEA) pointed out that in hydrogen production systems driven by fluctuating wind and solar power, frequent start-ups and shutdowns of electrolyzers due to power mismatch failures result in annual hydrogen production losses of up to 15% to 20%. The underlying mechanism is as follows (i.e., power fluctuations → control failures → electrolyzer start-ups and shutdowns → abrupt changes in concentration gradients → electrode passivation + increased energy consumption → 15-20% hydrogen production loss): when the input power is lower than the minimum operating point of the electrolyzer, the system is forced to shut down. The restart process not only consumes additional energy but also causes electrode passivation due to abrupt changes in the electrolyte concentration gradient. During the power recovery phase, control delays prevent the electrolyzer from matching available power in a timely manner, resulting in the curtailment of renewable energy. This series of chain reactions increases the LCOH (levelized cost of hydrogen) of current hydrogen production systems by more than 25% compared to the theoretical value, becoming a core obstacle to the large-scale development of the industry.

[0006] Therefore, developing a novel control method that can synergistically optimize the dynamic response characteristics of PEM and ALK, achieve adaptive power allocation, and suppress system oscillations has become a key path to overcome the bottleneck of renewable energy hydrogen production technology. Summary of the Invention

[0007] The purpose of this invention is to design an ALK-PEM electrolysis hydrogen production synchronous control method based on direct torque and droop control, which addresses the shortcomings of existing technologies.

[0008] The first aspect of this invention is to provide a synchronous control method for hydrogen production by electrolysis in ALK-PEM based on direct torque and droop control, which is implemented based on a "DTC-adaptive droop" dual-loop collaborative control architecture. The "DTC-adaptive droop" dual-loop collaborative control architecture includes an inner loop and an outer loop. The inner loop is used for real-time power tracking of the electrolyzer based on improved DTC control, and the outer loop is used for adjusting the control coefficient for adaptive droop based on a state observer, thereby realizing dynamic power distribution between the alkaline electrolyzer (ALK) and the proton exchange membrane electrolyzer (PEM).

[0009] The synchronization control method includes:

[0010] S1, Real-time acquisition of the total power input P from the wind and solar power sources. total State of charge of hydrogen storage system And the absolute value of the rate of change of power |dP / dt|;

[0011] S2, the direct torque control algorithm is used to generate the electrolyzer power command, wherein the electrolyzer includes an alkaline electrolyzer ALK and a proton exchange membrane electrolyzer PEM;

[0012] S3, based on the state of charge of the hydrogen storage system And the absolute value of the power change rate |dP / dt| is dynamically calculated as the adaptive droop coefficient, as shown in equation (2);

[0013]

[0014] Where: R base R represents the basic sag coefficient, which is the coefficient of performance for a proton exchange membrane electrolyzer (PEM). base We take 0.05 to obtain R. droop,PEM For alkaline electrolyzers ALK, R base We take 0.02 to obtain R. droop,ALK ; The state of charge of the hydrogen storage system is represented by |dP / dt|, which represents the absolute value of the rate of change of power, in units of kW / s or %P_rated / s; α, β, and γ are multiple weighting factors.

[0015] S4, the electrolyzer power P of the proton exchange membrane electrolyzer (PEM) and the alkaline electrolyzer (ALK) is allocated. PEM and P ALK ;

[0016] S5, P PEM and P ALK The generated instructions are input to the DTC controller, which generates PWM drive signals to drive the PEM and ALK electrolytic cells respectively.

[0017] Preferably, S2 includes:

[0018] S21, the input power P of the electrolytic cell ele Mapped to equivalent electromagnetic torque T e As shown in equation (1):

[0019] T e =K p ·(P ref -P actual )+K i ∫(P ref -P actual )dt (1);

[0020] Among them, P ref P represents the reference power of the electrolytic cell. actual P represents the actual power of the electrolytic cell. ref -P actual The input power P of the electrolytic cell ele K p K represents the absolute power conversion factor. i Represents the cumulative power conversion factor;

[0021] S22, the electrolyte ion concentrations of ALK electrolyte and PEM electrolyte are mapped to equivalent magnetic flux ψ using a preset concentration-magnetic flux mapping table; the electrolyte ions include OH-. - and H + ;

[0022] S23, based on equivalent electromagnetic torque T e The equivalent magnetic flux ψ generates the electrolytic cell power command.

[0023] Preferably, S22 includes:

[0024] (1) Establish a table of correspondence between electrolyte ion concentration difference ΔC and equivalent magnetic flux ψ, as shown in Table 1 below, wherein the electrolyte ion concentration difference ΔC is the difference in ion concentration gradient when the two electrolyzers are working.

[0025] Table 1

[0026] Ion concentration difference ΔC (mol / L) Equivalent magnetic flux linkage ψ(V·s) ΔC<0.1 0.05–0.08 0.1≤ΔC<0.30 0.08–0.12 ΔC≥0.3 0.12–0.15

[0027] (2) Real-time monitoring of H in the proton exchange membrane electrolyzer (PEM) + The concentration of OH- in the alkaline electrolyzer ALK is compared with the concentration of OH- in the alkaline electrolyzer. The difference in electrolyte ion concentration ΔC is calculated according to equation (3):

[0028]

[0029] (3) Determine the equivalent flux linkage ψ by looking up ΔC in the table.

[0030] Preferably, S23 includes:

[0031] Based on equivalent electromagnetic torque T e Generate torque command Te;

[0032] Generate flux linkage instruction ψe based on equivalent flux linkage ψ;

[0033] A voltage vector switching table is generated based on the torque command Te and the flux linkage command ψe as the power command for the electrolytic cell.

[0034] Preferably, in S3, the following is set:

[0035] Weighting constraints, absolute value constraints on power change rate, and constraints on electrolytic cell lifespan optimization;

[0036] The weighting constraints include:

[0037] α takes values ​​ranging from 0.2 to 0.5 and is used for adjustment. Sensitivity;

[0038] β takes values ​​ranging from 1.5 to 3.0 and is used to adjust the decay rate of |dP / dt|.

[0039] γ takes values ​​ranging from 0.4 to 0.8 and is used for balancing. The weights of |dP / dt|;

[0040] The absolute value constraint on the power change rate includes:

[0041] When |dP / dt| > 10%P_rated / s, R is forcibly set. droop，PEM =0.01 to ensure PEM prioritizes response to power surges; P_rated represents the system's rated power; >10%P_rated / s indicates that the power change per second exceeds 10% of the system's rated power;

[0042] The limitations for optimizing the lifespan of the electrolyzer include:

[0043] (1) When the PEM current density J PEM >1.8A / cm 2 At that time, forcibly reducing Te makes J PEM ≤1.8A / cm 2 ;

[0044] (2) When the temperature of ALK is T ALK At temperatures above 80°C, increase the magnetic flux command ψ to improve electrolyte flow rate for cooling.

[0045] (3) For every 1000 hours of cumulative operating time, R will be... base，PEM Increase by 0.005 to compensate for catalyst degradation.

[0046] Preferably, S4 includes:

[0047] S41, according to formula (4), the initial allocation of electrolytic cell power for proton exchange membrane electrolyzer PEM and alkaline electrolyzer ALK is carried out;

[0048]

[0049] S42, determine the current control mode, and determine whether to switch the control mode and the power allocation between the proton exchange membrane electrolyzer (PEM) and the alkaline electrolyzer (ALK) after the control mode switch, including:

[0050] Based on the condition that |dP / dt| > 5%P_rated / s, the current control mode is determined to be fluctuation mode, and therefore, according to P... PEM =min(P total ·80%, P PEM,max ) to allocate;

[0051] Based on the condition that |dP / dt|≤5%P_rated / s, the current control mode is determined to be a steady-state mode, and thus, according to P...PEM =min Distribute;

[0052] The remaining power is dynamically supplemented by another electrolytic cell.

[0053] Preferably, the The calculation process includes:

[0054] Step A: Measure the pressure P (unit: MPa) and temperature T (unit: K) of the hydrogen storage tank;

[0055] Step B: Calculate the mass of hydrogen gas using the real gas law.

[0056]

[0057] Where Z is the compressibility factor and R is the gas constant. V represents the tank volume;

[0058] Step C, press Output, m max To design the maximum hydrogen storage capacity.

[0059] A second aspect of the present invention is to provide a control system for implementing the control method of the first aspect, comprising:

[0060] The data acquisition module, including LEM CDT series current sensors and voltage divider circuits, is used to acquire DC bus power P in real time. total ;

[0061] The DTC execution module includes a TI chip and driver circuit, a torque hysteresis comparator, a flux linkage hysteresis comparator, and a switching meter selector. The TI chip is used to run torque-flux linkage dual closed-loop control, generating six PWM signals. The driver circuit includes an IGBT half-bridge module. The torque hysteresis comparator limits the deviation of Te from the measured torque to within ±3 N·m. The flux linkage hysteresis comparator limits the deviation of ψ from the measured flux linkage to within ±0.02 V·s. The switching meter selector selects the voltage vector based on the hysteresis output.

[0062] The adaptive droop calculation module includes a function for implementing exponential operations. FPGA, state observer, and parameters R base The memory; wherein the inputs of the state observer include: electrolyzer voltage U, current I, temperature T, and ion concentration C; the output of the state observer includes parameters that cannot be directly measured, including: catalyst activity coefficient and membrane water content;

[0063] The electrolyzer interface module includes a PEM cell-side interface submodule and an ALK cell-side interface submodule. The PEM cell-side interface submodule is equipped with a gas-liquid separator and a temperature sensor. The ALK cell-side interface submodule is equipped with an alkali circulation pump and a concentration detection electrode.

[0064] Preferably, the catalyst activity coefficient η cat The calculation formula is shown in equation (6):

[0065]

[0066] Where k1 is the activity reference constant, i.e., the theoretical maximum activity of the novel catalyst at infinite temperature; T is the absolute temperature of the catalyst, in K; R is the gas constant; E a This represents the energy barrier for electrochemical reactions occurring on the catalyst surface in the electrolyzer;

[0067] The formula for calculating the membrane water content λ is shown in equation (7):

[0068] λ=k2·∫(II threshold )dt (7);

[0069] Where k2 is the water migration coefficient, i.e., the net migration of water molecules caused by unit charge migration; I is the real-time operating current; I threshold The critical sustaining current is the minimum current required to maintain the membrane at its minimum water content; below this value, the membrane dehydrates. ∫(II) threshold dt represents the cumulative amount of purified water migration;

[0070] η cat Substituting λ into formula (2) for the adaptive droop coefficient, we obtain the dynamic adaptive droop coefficient R'. droop ;

[0071]

[0072] Where δ is the membrane state weighting factor, typically ranging from 0.05 to 0.1, and its control logic is as follows:

[0073] When λ < 16, the control action is to increase the PEM power allocation and force humidification;

[0074] When λ>22, the control action is to reduce the PEM power and start the anode drain valve.

[0075] A third aspect of the present invention is to provide a hydrogen production apparatus including the control system of the second aspect, further comprising:

[0076] PEM electrolytic cell unit, ALK electrolytic cell unit and wind and solar power interface;

[0077] The hydrogen production equipment has a safety protection mechanism, which includes when The pressure relief valve is triggered when |dP / dt| > 20% P_rated / s; the supercapacitor buffer is activated when |dP / dt| > 20% P_rated / s.

[0078] A fourth aspect of the present invention provides an electronic device including a processor and a memory, the memory storing a plurality of instructions, the processor being configured to read the instructions and execute the method as described in the first aspect.

[0079] A fifth aspect of the present invention provides a computer-readable storage medium storing a plurality of instructions which can be read by a processor and executed as described in the first aspect.

[0080] The beneficial effects of the method and system of the present invention are as follows:

[0081] (1) Improved dynamic response: The response speed of the ALK electrolyzer is increased by 10 times, and the risk of PEM overload is reduced by 90%;

[0082] (2) Efficiency optimization: The average hydrogen production efficiency is improved by 5% to 8% under wind and solar fluctuations;

[0083] (3) Extended lifespan: The number of start-ups and shutdowns of the electrolytic cell is reduced by 70%, extending the lifespan of the equipment;

[0084] (4) Compatibility: Applicable to ALK / PEM mixed stacks and pure PEM and pure ALK systems. Attached Figure Description

[0085] To more clearly illustrate the technical solutions in the specific embodiments or related technologies of the present invention, the drawings used in the description of the specific embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0086] Figure 1 A flowchart of the ALK-PEM electrolysis hydrogen production synchronous control method based on direct torque and droop control according to an embodiment of the present invention;

[0087] Figure 2 This is a flowchart of step S2 of the ALK-PEM electrolysis hydrogen production synchronous control method based on direct torque and droop control provided in an embodiment of the present invention.

[0088] Figure 3 This is a structural diagram of an electronic device provided according to an embodiment of the present invention. Detailed Implementation

[0089] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0090] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0091] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0092] Example 1

[0093] like Figure 1 As shown, this embodiment provides a synchronous control method for ALK-PEM electrolysis hydrogen production based on direct torque and droop control. It is implemented based on a "DTC-adaptive droop" dual-loop collaborative control architecture, which includes an inner loop and an outer loop. The inner loop is used for real-time power tracking of the electrolyzer based on improved DTC control, and the outer loop is used for adjusting the control coefficient for adaptive droop based on a state observer, thereby realizing dynamic power distribution between the alkaline electrolyzer ALK and the proton exchange membrane electrolyzer PEM.

[0094] The synchronization control method includes:

[0095] S1, Real-time acquisition of the total power input P from the wind and solar power sources. total State of charge of hydrogen storage system And the absolute value of the rate of change of power |dP / dt|;

[0096] S2, The direct torque control (DTC) algorithm is used to generate the electrolyzer power command, wherein the electrolyzer includes an alkaline electrolyzer ALK and a proton exchange membrane electrolyzer PEM;

[0097] like Figure 2 As shown, in a preferred embodiment, S2 includes:

[0098] S21, the input power P of the electrolytic cell ele Mapped to equivalent electromagnetic torque T e As shown in equation (1):

[0099] T e =K p ·(P ref -P actual )+K i ∫(P ref -P actual )dt (1);

[0100] Among them, P ref P represents the reference power of the electrolytic cell. actual P represents the actual power of the electrolytic cell. ref -P actual The input power P of the electrolytic cell ele K p K represents the absolute power conversion factor. i Represents the cumulative power conversion factor;

[0101] S22, the electrolyte ion concentrations of ALK electrolyte and PEM electrolyte are mapped to equivalent magnetic flux ψ using a preset concentration-magnetic flux mapping table; the electrolyte ions include OH-. - and H + ;

[0102] The ALK electrolyte is a 30% KOH aqueous solution, which mainly relies on OH-. - Ion conduction, but K actually exists. + H + H3O + Multiple ions participate in charge balance. However, ion conduction in a PEM electrolyzer depends entirely on H+. + (Protons), which is the fundamental reason for its fast response speed. However, there is also O2-derived oxygen ion adsorption on the surface of the PEM anode catalyst.

[0103] For alkaline electrolytic cells, ALK should be OH. - Concentration is the dominant factor, while in a proton exchange membrane electrolyzer (PEM), the H+ content within the membrane is the primary factor. + Concentration (determined by water content).

[0104] S23, based on equivalent electromagnetic torque T e The equivalent magnetic flux ψ generates the electrolytic cell power command.

[0105] The technical advantages of implementing S2 are: reducing the response time to 50ms (for proton exchange membrane electrolyzers, PEM) and 200ms (for alkaline electrolyzers, ALK), respectively.

[0106] S3, based on the state of charge of the hydrogen storage system And the absolute value of the power change rate |dP / dt| is dynamically calculated as the adaptive droop coefficient, as shown in equation (2);

[0107]

[0108] Where: R base R represents the basic sag coefficient, which is the coefficient of performance for a proton exchange membrane electrolyzer (PEM). base We take 0.05 to obtain R. droop,PEM For alkaline electrolyzers ALK, R base We take 0.02 to obtain R. droop,ALK ; The state of charge of the hydrogen storage system is represented by |dP / dt|, which represents the absolute value of the rate of change of power, in units of kW / s or %P_rated / s; α, β, and γ are multiple weighting factors.

[0109] S4, the electrolyzer power P of the proton exchange membrane electrolyzer (PEM) and the alkaline electrolyzer (ALK) is allocated. PEM and P ALK ;

[0110] S5, P PEM and P ALK The generated instructions are input to the DTC controller, which generates PWM drive signals to drive the PEM and ALK electrolytic cells respectively.

[0111] In a preferred embodiment, S22 includes:

[0112] (1) Establish a table of correspondence between electrolyte ion concentration difference ΔC and equivalent magnetic flux ψ, as shown in Table 1 below, wherein the electrolyte ion concentration difference ΔC is the difference in ion concentration gradient when the two electrolyzers are working.

[0113] Table 1

[0114]

[0115]

[0116] (2) Real-time monitoring of H in the proton exchange membrane electrolyzer (PEM) + The concentration of OH- in the alkaline electrolyzer ALK is compared with the concentration of OH- in the alkaline electrolyzer. The difference in electrolyte ion concentration ΔC is calculated according to equation (3):

[0117]

[0118] (3) Determine the equivalent flux linkage ψ by looking up ΔC in the table.

[0119] In a preferred embodiment, S23 includes:

[0120] Based on equivalent electromagnetic torque T e Generate torque command Te;

[0121] Generate flux linkage instruction ψe based on equivalent flux linkage ψ;

[0122] A voltage vector switching table is generated based on the torque command Te and the flux linkage command ψe as the power command for the electrolytic cell.

[0123] In a preferred embodiment, S3 is configured as follows:

[0124] Weighting constraints, absolute value constraints on power change rate, and constraints on electrolytic cell lifespan optimization;

[0125] The weighting constraints include:

[0126] α takes values ​​ranging from 0.2 to 0.5 and is used for adjustment. Sensitivity;

[0127] β takes values ​​ranging from 1.5 to 3.0 and is used to adjust the decay rate of |dP / dt|.

[0128] γ takes values ​​ranging from 0.4 to 0.8 and is used for balancing. The weights of |dP / dt|;

[0129] The absolute value constraint on the power change rate includes:

[0130] When |dP / dt| > 10%P_rated / s, R is forcibly set. droop，PEM =0.01 to ensure PEM prioritizes response to power surges; P_rated represents the system's rated power; >10%P_rated / s indicates that the power change per second exceeds 10% of the system's rated power;

[0131] For example, if the system rated power P_rated = 100kW, then the threshold is 100 × 10% = 10kW / s;

[0132] The trigger condition is: power in the first second = 50kW → power in the second second ≥ 60kW or ≤ 40kW.

[0133] (a) When |dP / dt| > 10%P_rated / s, R is forcibly set. droop，PEM =0.01 This corresponds to the actual operating scenario where the PEM prioritizes response to power changes.

[0134] 1. Typical sudden events in wind and solar power generation are shown in Table 2 below.

[0135] Table 2

[0136]

[0137]

[0138] 2. Impact on the electrolytic cell

[0139] (1) PEM electrolytic cell: Current density abrupt change > 0.2 A / (cm) 2 •s)→ Membrane dehydration risk increases by 300%;

[0140] (2) ALK electrolytic cell: Temperature change rate > 2℃ / s → Probability of thermal stress cracking increases by 50%.

[0141] (II) The Core Role in Control Logic

[0142] This threshold directly determines the switching of control modes and the forced adjustment of the droop coefficient:

[0143] Control response strategy:

[0144] 1. Preferred response of PEM electrolyzer:

[0145] (1) Force the PEM droop coefficient to the minimum value (0.01) so that it can bear >90% of the mutation power;

[0146] (2) Basis: PEM response time (50ms) is much faster than ALK (200ms);

[0147] 2. ALK electrolytic cell power freeze:

[0148] Keep the ALK power constant to avoid oscillations caused by response lag.

[0149] (III) Engineering Implementation Testing Methods

[0150] 1. Calculation of power change rate

[0151] Using a moving-time window difference algorithm:

[0152] / / Code (real-time calculation within the controller)

[0153] float dp_dt = 0;

[0154] float power_window

[10] ; / / Stores the power values ​​of the last 10 sampling points (sampling period 10ms).

[0155] for(int i = 1; i < 10; i++){

[0156] dp_dt+=(power_window[i]-power_window[i-1]) / 0.01; / / Unit: kW / s

[0157] }

[0158] dp_dt = fabs(dp_dt / 9); / / Get the absolute value of the average rate of change within a 10ms window

[0159] 2. Hardware protection logic

[0160] When |dP / dt| > 10% P_rated / s is detected: the supercapacitor buffer circuit is activated (response time < 5ms) and a fault code is sent to the SCADA system (alarm level: III).

[0161] (iv) Scientific basis for threshold setting

[0162] The experimental data (tested using a 200kW hybrid electrolysis system) is shown in Table 3:

[0163] Table 3

[0164]

[0165] Conclusion: 10% is the optimal solution for balancing efficiency and safety.

[0166] (v) Systemic risks exceeding the threshold

[0167] 1. Electrical risk: DC bus voltage overshoot (>±15%) → IGBT overvoltage breakdown;

[0168] 2. Electrochemical risks:

[0169] (1) PEM: Local hot spots >100℃ → perfluorosulfonic acid membrane degradation;

[0170] (2) ALK: Concentration polarization → oxygen evolution side reaction (2OH- → 1 / 2O2 + H2O + 2e-) - );

[0171] 3. Mechanical risks:

[0172] Cavitation in alkaline solution circulating pump → Flow rate fluctuation ±30%

[0173] Set "When |dP / dt|>10%P_rated / s, force R to be set" droop，PEM =0.01 to ensure PEM preferential response to mutation power" is not only a quantitative indicator of the power mutation intensity, but also:

[0174] (1) Trigger signal for control mode switching - start PEM priority response mechanism;

[0175] (2) The critical point of system safety protection - activation of buffer circuit and power freeze;

[0176] (3) The balance threshold between lifetime and efficiency - the optimal solution based on experimental data.

[0177] The design of this parameter directly determines the robustness of the hybrid hydrogen production system under fluctuating conditions, and is one of the core technical features of the present invention.

[0178] The limitations for optimizing the lifespan of the electrolyzer include:

[0179] (1) When the PEM current density J PEM >1.8A / cm 2 At that time, forcibly reducing Te makes J PEM ≤1.8A / cm 2 ;

[0180] (2) When the temperature of ALK is T ALK At temperatures above 80°C, increase the magnetic flux command ψ to improve electrolyte flow rate for cooling.

[0181] (3) For every 1000 hours of cumulative operating time, R will be... base，PEM Increase by 0.005 to compensate for catalyst degradation.

[0182] In a preferred embodiment, S4 includes:

[0183] S41, according to formula (4), the initial allocation of electrolytic cell power for proton exchange membrane electrolyzer PEM and alkaline electrolyzer ALK is carried out;

[0184]

[0185] S42, determine the current control mode, and determine whether to switch the control mode and the power allocation between the proton exchange membrane electrolyzer (PEM) and the alkaline electrolyzer (ALK) after the control mode switch, including:

[0186] Based on the condition that |dP / dt| > 5%P_rated / s, the current control mode is determined to be fluctuation mode, and therefore, according to P... PEM =min(P total ·80%, P PEM,max ) to allocate;

[0187] Based on the condition that |dP / dt|≤5%P_rated / s, the current control mode is determined to be a steady-state mode, and thus, according to P... PEM =min Distribute;

[0188] The remaining power is dynamically supplemented by another electrolytic cell.

[0189] As a preferred embodiment, the The calculation process includes:

[0190] Step A: Measure the pressure P (unit: MPa) and temperature T (unit: K) of the hydrogen storage tank;

[0191] Step B: Calculate the mass of hydrogen gas using the real gas law.

[0192]

[0193] Where Z is the compressibility factor and R is the gas constant. V represents the tank volume;

[0194] Step C, press Output, m max To design the maximum hydrogen storage capacity.

[0195] Example 2

[0196] This embodiment provides a control system for implementing the control method of the first aspect, including:

[0197] The data acquisition module, including LEM CDT series current sensors and voltage divider circuits, is used to acquire DC bus power P in real time. total ;

[0198] The DTC execution module includes a TI TMS320F28379D chip and driver circuit, a torque hysteresis comparator, a flux linkage hysteresis comparator, and a switch meter selector. The TI TMS320F28379D chip is used to run torque-flux linkage dual closed-loop control, generating 6 PWM signals. The driver circuit includes an IGBT half-bridge module (model: Infineon FF450R12KE4). The torque hysteresis comparator limits the deviation of Te from the measured torque to within ±3 N·m. The flux linkage hysteresis comparator limits the deviation of ψ from the measured flux linkage to within ±0.02 V·s. The switch meter selector selects the voltage vector based on the hysteresis output. The correspondence between the torque deviation, flux linkage deviation, and voltage vector is shown in Table 4 below.

[0199] Table 4

[0200]

[0201] The adaptive droop calculation module includes a function for implementing exponential operations. The FPGA (Xilinx XC7Z020), state observer, and parameters R are used to store the parameters. base The EEPROM (AT24C256) is used; the inputs of the state observer include: electrolyzer voltage U, current I, temperature T, and ion concentration C; the outputs of the state observer include parameters that cannot be directly measured, including: catalyst activity coefficient and membrane water content; wherein the catalyst activity coefficient η cat The calculation formula is shown in equation (6):

[0202]

[0203] Where k1 is the activity reference constant, i.e., the theoretical maximum activity of the novel catalyst at infinite temperature; T is the absolute temperature of the catalyst, in K; R is the gas constant; E a This represents the energy barrier for electrochemical reactions occurring on the catalyst surface in the electrolyzer;

[0204] The formula for calculating the membrane water content λ is shown in equation (7):

[0205] λ=k2·∫(II threshold )dt (7);

[0206] Where k2 is the water migration coefficient, i.e., the net migration of water molecules caused by unit charge migration; I is the real-time operating current; I threshold The critical sustaining current is the minimum current required to maintain the membrane at its minimum water content; below this value, the membrane dehydrates. ∫(II) threshold dt represents the cumulative amount of purified water migration;

[0207] η cat Substituting λ into formula (2) for the adaptive droop coefficient, we obtain the dynamic adaptive droop coefficient R'. droop ;

[0208]

[0209] Where δ is the membrane state weighting factor, typically ranging from 0.05 to 0.1, and its control logic is as follows:

[0210] When λ < 16, the control action is to increase the PEM power allocation and force humidification;

[0211] When λ>22, the control action is to reduce the PEM power and start the anode drain valve;

[0212] The electrolyzer interface module includes a PEM cell-side interface submodule and an ALK cell-side interface submodule. The PEM cell-side interface submodule is equipped with a gas-liquid separator and a temperature sensor (PT100). The ALK cell-side interface submodule is equipped with an alkali circulation pump and a concentration detection electrode.

[0213] Example 3

[0214] This embodiment provides a hydrogen production device including a control system of the second aspect, and further includes:

[0215] The PEM electrolysis cell unit has a rated power of 50kW and a membrane electrode area of ​​250cm². 2 Iridium loading 2 mg / cm³ 2 Operating pressure: 30 bar; Temperature: 60–80℃;

[0216] The ALK electrolytic cell unit has a rated power of 150kW and an electrode area of ​​0.5m². 2 The nickel mesh substrate is plated with cobalt-manganese catalyst; the electrolyte is a 30% KOH solution with a flow rate of 50 L / min.

[0217] The wind and solar power interface supports DC 800V±20% input and MPPT tracking efficiency ≥99%.

[0218] The hydrogen production equipment has a safety protection mechanism, which includes when The pressure relief valve is triggered when |dP / dt| > 20% P_rated / s; the supercapacitor buffer is activated when |dP / dt| > 20% P_rated / s.

[0219] The present invention also provides a memory that stores multiple instructions for implementing the method as described in Embodiment 1.

[0220] like Figure 2 As shown, the present invention also provides an electronic device, including a processor 301 and a memory 302 connected to the processor 301. The memory 302 stores a plurality of instructions, which can be loaded and executed by the processor to enable the processor to perform the method as described in Embodiment 1.

[0221] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; 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 or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A synchronous control method for ALK-PEM electrolytic hydrogen generation based on direct torque and droop control, characterized by, The dynamic power distribution of the alkaline electrolytic cell ALK and the proton exchange membrane electrolytic cell PEM is realized based on a "DTC-adaptive droop" double-loop cooperative control architecture, wherein the "DTC-adaptive droop" double-loop cooperative control architecture comprises an inner loop and an outer loop, the inner loop is used for real-time power tracking of the electrolytic cell based on improved DTC control, and the outer loop is used for adaptive droop control coefficient adjustment based on a state observer. The synchronous control method comprises: S1, real-time collection of total power input by wind and solar power , state of charge of hydrogen storage system , and absolute value of power change rate ; S2, generating an electrolytic cell power instruction by using a direct torque control algorithm, wherein the electrolytic cell comprises an alkaline electrolytic cell ALK and a proton exchange membrane electrolytic cell PEM; S3, based on the state of charge of the hydrogen storage system and the absolute value of the power change rate | | dynamically calculating the adaptive droop coefficient, as shown in equation (2); （2）; wherein: represents the base sag coefficient, for a proton exchange membrane electrolyzer PEM, is taken as 0.05, so that , for an alkaline electrolyzer ALK, is taken as 0.02, so that ; represents the state of charge of the hydrogen storage system; represents the absolute value of the power change rate, in %P_rated / s; , and are a plurality of weight factors; S4, allocating cell power of a proton exchange membrane cell, PEM, and an alkaline cell, ALK and ; S5, the and formed instruction input DTC controller, respectively driving PEM and ALK electrolytic tank PWM drive signal; The S2 comprises: S21, mapping the input power of the electrolytic cell to an equivalent electromagnetic torque as shown in equation (1): （1）； wherein, represents the reference power of the electrolytic cell, represents the actual power of the electrolytic cell, represents the input power of the electrolytic cell , represents the absolute power conversion factor, represents the cumulative power conversion factor; S22, mapping electrolyte ion concentrations of the ALK electrolyte and the PEM electrolyte into equivalent flux ψ through a preset concentration-flux mapping table; the electrolyte ions include OH⁻ and H⁺; S23, generating the cell power instruction based on the equivalent electromagnetic torque and the equivalent flux linkage ψ The S4 comprises: S41, performing preliminary distribution of electrolytic cell power of the proton exchange membrane electrolytic cell PEM and the alkaline electrolytic cell ALK according to formula (4); ; ； (4)； S42, judging the current control mode, and judging whether to switch the control mode and the distribution of the electrolytic cell power of the proton exchange membrane electrolytic cell PEM and the alkaline electrolytic cell ALK after the control mode is switched, comprising: Based on | P_rated / s When | P_rated / s is greater than 5%, it is determined that the current control mode is a fluctuation mode, and thus the power is allocated according to the fluctuation mode. When | P_rated / s is greater than 5%, it is determined that the current control mode is a fluctuation mode, and thus the Based on | When |≤5% P_rated / s, the current control mode is determined to be steady-state mode, and thus follows the... Distribute; The remaining power is dynamically supplemented by the other electrolytic cell.

2. A synchronous control method of ALK-PEM electrolysis for hydrogen production based on direct torque and droop control according to claim 1, characterized in that, The S22 comprises: (1) establishing a corresponding relationship table of electrolyte ion concentration difference ΔC and equivalent flux ψ, as shown in Table 1 below, wherein the electrolyte ion concentration difference ΔC is the ion concentration gradient difference when the two electrolytic cells are working; Table 1 (2) real-time monitoring of H⁺ concentration of the proton exchange membrane electrolytic cell PEM and OH⁻ concentration of the alkaline electrolytic cell ALK, and calculating the electrolyte ion concentration difference ΔC according to formula (3): (3) (3) determining the equivalent flux ψ according to the table of ΔC.

3. A synchronous control method of ALK-PEM electrolytic hydrogen generation based on direct torque and droop control according to claim 2, characterized by, The S23 comprises: Equivalent electromagnetic torque Generate torque command Te; generating a flux instruction ψe based on the equivalent flux ψ; generating a voltage vector switch table as the electrolytic cell power instruction based on the torque instruction Te and the flux instruction ψe.

4. The method of claim 3, wherein the method is characterized by: In the S3, the following conditions are set: weight limit condition, absolute value limit condition of power change rate, and electrolytic cell life optimization limit condition; The weight limit condition comprises: The value range is 0.2 - 0.5, used to adjust the sensitivity of ; The value range is 1.5-3.0, used to adjust the decay rate of ∣ ∣ The value range is 0.4 - 0.8, used to balance The weight of | and The weight of | The absolute value limit condition of the power change rate comprises: When ∣ ∣>10% P_rated / s, set to 1 to ensure that the PEM responds to sudden power changes first; P_rated represents the system rated power; >10% P_rated / s represents that the power change per second exceeds 10% of the system rated power; The electrolytic cell life optimization limit condition comprises: (1) When the PEM current density is forced to decrease Te ; (2) When the ALK temperature is increased, the flux command ψ is increased to increase the electrolyte flow rate cooling; (3) The cumulative operating time is increased by 1000 hours each time Up 0.005 to compensate for catalyst attenuation.

5. The method of claim 4, wherein the method is based on direct torque and droop control of the ALK-PEM electrolysis for hydrogen generation. The The computing process includes: Step A, Measure hydrogen storage tank pressure P in MPa and temperature T in K; Step B, hydrogen mass calculated from real gas equation of state ; (5); wherein, is a compression factor, is a gas constant, , is the tank volume; Step C, according to output, to design the maximum hydrogen storage mass.

6. A control system implementing the control method according to any one of claims 1 to 5, characterized in that, comprises: The data acquisition module comprises a LEM CDT series current sensor and a voltage dividing circuit, and is used for collecting the DC bus power in real time ; a DTC execution module comprising a TI chip and a driving circuit, a torque hysteresis comparator, a flux hysteresis comparator, and a switch table selector; wherein the TI chip is used to run torque-flux double-loop control to generate 6-way PWM signals; the driving circuit comprises an IGBT half-bridge module; the torque hysteresis comparator is used to limit the deviation of Te and the measured torque within ±3 N·m; the flux hysteresis comparator is used to limit the deviation of ψ and the measured flux within ±0.02 V·s; and the switch table selector is used to select a voltage vector according to the hysteresis output; An adaptive droop calculation module comprising an FPGA for implementing an exponential operation a state observer and a memory for storing parameters ; wherein the inputs of the state observer comprise: cell voltage U, current I, temperature T and ion concentration C; the outputs of the state observer comprise non-directly measurable parameters, which comprise: catalyst activity coefficient and membrane water content; an electrolytic cell interface module comprising a PEM tank side interface submodule and an ALK tank side interface submodule, wherein the PEM tank side interface submodule is configured with a gas-liquid separator and a temperature sensor; and the ALK tank side interface submodule is configured with an alkali liquid circulating pump and a concentration detection electrode.

7. The control system of claim 6, wherein, The catalyst activity coefficient The calculation formula is shown as formula (6): （6）； wherein, is the activity reference constant, i.e. the theoretical maximum activity of a fresh catalyst at an infinite high temperature; T is the absolute temperature of the catalyst in K; is the gas constant; represents the energy barrier of the electrochemical reaction occurring on the surface of the catalyst in the electrolytic cell; The film moisture content The calculation formula is shown in equation (7): （7）； wherein, is the water transport coefficient, i.e. the net amount of water molecules transported per unit of charge transported; is the real-time working current; is the critical sustaining current, i.e. the minimum current to maintain the minimum water content of the membrane, below which the membrane dehydrates; represents the cumulative net water transport; Bringing the formula (2) of adaptive droop coefficient into the formula (1) of the output voltage of the inverter, the output voltage of the inverter is obtained as follows: And The formula (2) of the dynamic adaptive droop coefficient is obtained by bringing the adaptive droop coefficient into the formula (2); ​ （8）； wherein is a film state weight factor, typically 0.05 to 0.1, with control logic: When λ < 16, the control action is to increase the PEM power allocation, forcing humidification; When λ > 22, the control action is to decrease the PEM power, starting the anode drain valve.

8. A hydrogen production plant comprising a control system according to any one of claims 6-7, characterized in that, Also comprising: A PEM electrolyzer cell unit, an ALK electrolyzer cell unit, and a wind-solar power interface; The hydrogen production apparatus has a safety protection mechanism, which includes triggering a pressure relief valve when and starting a supercapacitor buffer when | > 20% P_rated / s.

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