Electrolytic hydrogen production safety and emergency switching system based on multistage interlocking logic

Abstract

The invention belongs to the technical field of electrolytic hydrogen production process control, and relates to an electrolytic hydrogen production safety and emergency switching system based on multistage interlocking logic, and the system comprises a data acquisition module which collects and synchronizes electrical and fluid parameters and feedback states, and generates a basic operation state set; the pressure prediction module is used for calculating bubble influence by using a bubble lag compensation model and generating a future pressure prediction vector; the discharge capacity calculation module is used for calling a valve curve to obtain a flow coefficient under the current opening degree and generating a mechanical response envelope line; the logic comparison module is used for comparing the prediction vector with the envelope line, and generating a locking signal to restrain rectifier power adjustment when the gas machine response is mismatched; and the grading interlocking execution module activates an L1 or L2 grade strategy according to differential pressure convergence and concentration. According to the invention, the problems of pressure control lagging and insufficient safety margin caused by mismatching of the gas production rate and the mechanical discharge capacity of the electrolytic hydrogen production system under rapid power fluctuation are solved.

Description

Technical Field

[0001] This invention belongs to the technical field of electrolytic hydrogen production process control, and relates to an electrolytic hydrogen production safety and emergency switching system based on multi-level interlocking logic. Background Technology

[0002] Hydrogen production through electrolysis is often coupled with fluctuating renewable energy sources such as wind or solar power, making operational safety a key concern in this field. Electrolyzer systems involve the coupling of electrochemical reactions, fluid dynamics, and thermodynamic processes, and their internal states are highly sensitive to changes in input power. Power fluctuations cause changes in the hydrogen production rate, which in turn leads to pressure fluctuations in the gas-liquid separator and subsequent pipelines. If the response speed of the pressure control system cannot keep up with the rate of increase in hydrogen production, it may lead to system overpressure or trigger unplanned releases of safety valves, potentially impacting the equipment.

[0003] Existing technologies typically employ feedback control logic, which involves monitoring system pressure using pressure sensors and adjusting the opening of downstream pressure regulating valves using a proportional-integral-derivative (PID) controller to maintain stable system pressure. Furthermore, to address potentially hazardous operating conditions, the system is generally equipped with hard-interlock protection logic based on fixed thresholds. When the pressure or gas concentration exceeds preset limits, a derating or emergency shutdown procedure is triggered.

[0004] However, the aforementioned feedback control methods rely on the measurement and correction of existing pressure deviations, and the physical action delays of mechanical actuators such as pressure regulating valves lead to time lags in the control loop. There is a lack of effective modeling for the hysteresis effect of bubbles inside the electrolytic cell. In actual operating conditions, there is a significant time delay from current change to bubble desorption and then to pressure change, and mechanical components such as pressure regulating valves also exhibit physical action lags. Traditional control methods fail to correlate and match these two different time-scale hysteresis characteristics. When facing high-frequency or large-amplitude power fluctuations, this hysteresis may cause overshoot and oscillation in pressure control. Hard interlocking logic based on fixed thresholds is usually triggered after a certain deviation in the system state, and this triggering often leads to production interruptions, leaving room for improvement for continuous production processes. When dealing with the transient evolution of internal pressure caused by high current change rates, strategies relying solely on feedback control and threshold interlocking have limitations in matching mechanical response capabilities. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a safety and emergency switching system for hydrogen production via electrolysis based on multi-level interlocking logic.

[0006] A safety and emergency switching system for hydrogen production via electrolysis based on multi-level interlocking logic, comprising:

[0007] The data acquisition module is used to build a real-time data acquisition environment, collect electrical parameters, fluid parameters and actuator feedback status of the electrolytic cell system, and perform time synchronization processing to generate a basic operating status set.

[0008] The pressure prediction module, based on the basic operating state set, uses the bubble hysteresis compensation model to calculate the impact of bubbles generated by power fluctuations on system pressure, and generates a future pressure prediction vector that includes the pressure change trend within a future preset time window.

[0009] The discharge capacity calculation module, based on the valve status in the basic operating state set, calls the valve mechanical characteristic curve to obtain the flow coefficient of the pressure regulating valve under the current physical opening, and generates the mechanical response envelope characterizing the physical discharge capacity.

[0010] The logic comparison module compares the future pressure prediction vector with the mechanical response envelope in the time domain, and generates a power clamping lock signal to constrain the power regulation of the rectifier when the gas response mismatch is determined.

[0011] The hierarchical interlocking execution module, when the power clamping lock signal is activated, activates a hierarchical interlocking execution strategy, including L1 mode or L2 mode, based on the differential pressure convergence and gas concentration value in the basic operating state set.

[0012] A further aspect of the present invention includes a data acquisition module, which is used to perform the following operations:

[0013] The output current and voltage values ​​of the rectifier are acquired by a high-frequency data acquisition module, and the current change rate is calculated using a first-order backward differential algorithm.

[0014] The electrolyzer outlet temperature, the real-time pressure value in the gas-liquid separator, and the liquid level height at the gas-liquid interface are collected by process sensors.

[0015] The physical opening position of the pressure regulating valve and the valve action current feedback are read through the valve positioner.

[0016] The Network Time Protocol client is used to assign a unified timestamp to all the parameters collected above, and these parameters are aggregated into a structured data vector as the basic running status set.

[0017] A further aspect of the present invention includes a pressure prediction module, which performs the following operations:

[0018] Real-time output current value, current change rate and electrolytic cell outlet temperature are extracted from the basic operating status.

[0019] Based on Faraday's law of electrolysis, the reference gas production rate is calculated using the real-time output current value. At the same time, based on the preset electrolyte gas content function relationship, the incremental release of bubbles on the electrode surface caused by power fluctuations is calculated, and the bubble desorption delay time is calculated in combination with the electrolytic cell outlet temperature.

[0020] By using the baseline gas production rate, bubble release increment, and bubble desorption delay time, combined with the physical volume parameters of the gas-liquid separator, the real-time pressure value is modified by differential trend correction, and a future pressure prediction vector is output.

[0021] A further aspect of the present invention includes a discharge capacity calculation module, which performs the following operations:

[0022] Using the physical opening position of the basic operating status set as an index, query the pre-stored valve mechanical characteristic curve to obtain the flow coefficient of the pressure regulating valve at the current opening.

[0023] Based on the current physical opening position and the gas phase physical volume of the gas-liquid separator, the allowable pressure drop gradient of the system under the current pressure conditions is calculated, and the pressure drop gradient is defined as the mechanical response envelope.

[0024] A further aspect of the present invention includes a logic comparison module, which performs the following operations:

[0025] Extract the pressure rise slope from the future pressure prediction vector and the pressure fall gradient from the mechanical response envelope;

[0026] When the pressure rise slope exceeds the product of the pressure fall gradient and the preset safety margin coefficient, it is determined to be a gas turbine response mismatch, and a power clamping lock signal for the first logic state is generated.

[0027] The power clamping signal is mapped to the IGBT trigger unit of the rectifier to lock the rising edge of the PWM duty cycle and prevent the rectifier output current from increasing with the power command.

[0028] A further aspect of the present invention includes a hierarchical interlocking execution module, used to perform the following operations:

[0029] When the system is under the control of the power clamping lock signal, the actual pressure difference is calculated in real time. If the actual pressure difference does not converge within the preset time, the L1 level soft derating mode is triggered, the rectifier current setting value is reduced by a fixed step size and the circulating pump is kept running at full speed.

[0030] Real-time monitoring of the concentration of oxygen in hydrogen and the concentration of hydrogen in oxygen in the basic operating status;

[0031] When any concentration value approaches the preset lower explosion limit threshold, the L2 level controlled shutdown mode is triggered.

[0032] A further aspect of this invention is that the execution logic of the L2-level controlled shutdown mode is as follows:

[0033] Send a rectifier shutdown command and simultaneously activate the delay counter;

[0034] After the delay counter meets the preset cooling cycle, commands are sent sequentially to close the hydrogen-side outlet valve and the oxygen-side outlet valve to maintain positive pressure sealing of the system.

[0035] A further embodiment of the present invention includes a transient freeze module, which performs the following operations within the same instruction cycle that triggers the L2 level controlled shutdown mode:

[0036] Lock the basic operating state set at the trigger moment, and extract the valve physical opening position, gas-liquid interface liquid level height and system pressure difference value from it;

[0037] The captured data is marked as a thermal equilibrium trajectory snapshot and stored as the initial bias value of the PID controller when the system is reset and started.

[0038] A further embodiment of the present invention includes an emergency protection module, used to perform the following operations:

[0039] When a fire detection signal or an external emergency stop hardwired signal is detected, the L3 physical isolation process is triggered.

[0040] The bypass power clamping lock signal and the hierarchical interlocking execution strategy physically disconnect the main circuit power supply of the rectifier and the circulating pump, and trigger the pneumatic shut-off valve controlled by the safety instrument system to close due to power failure.

[0041] A further aspect of the present invention includes the L3 level physical isolation process further comprising:

[0042] At the same time as triggering the pneumatic shut-off valve to close, the nitrogen purging valve is opened in conjunction with the high-pressure nitrogen to physically isolate and replace residual gas in the hydrogen-side pipeline and oxygen-side pipeline.

[0043] Continuously monitor the gas concentration at the end of the pipeline, and only allow the nitrogen purging valve to be closed when the gas concentration is lower than the preset safety limit.

[0044] In summary, the present invention has the following beneficial technical effects:

[0045] 1. By constructing a real-time data acquisition environment and generating a basic operating status set, the electrical parameters, fluid parameters, and actuator feedback status of the electrolyzer were synchronized in time. Compared with traditional control methods that rely on independent and asynchronous sensor signals, this data aggregation mechanism reduces the calculation deviations introduced by sampling time differences, providing a unified and accurate data foundation for pressure prediction models and interlocking logic operations.

[0046] 2. By using a bubble hysteresis compensation model to predict future pressure change trends and constructing a mechanical response envelope based on the valve's mechanical characteristic curve, real-time comparison between the predicted gas production rate and the system's physical release capacity is achieved. This mechanism can identify the risk of gas response mismatch in advance based on the current change rate before the pressure sensor detects that the actual pressure exceeds the limit, thus shifting the safety intervention point forward and compensating for the physical hysteresis of the mechanical actuator to a certain extent.

[0047] 3. By logically comparing and generating a power clamping lockout signal when a response mismatch is detected, the power output command of the rectifier can be directly constrained at the physical level. When the predicted gas production rate exceeds the system's venting capacity, this strategy directly limits the increase in input power, rather than simply relying on the hysteretic regulation of downstream valves. This method of limiting at the source of disturbance helps reduce overshoot in the pressure control process and suppress system oscillations.

[0048] 4. By setting a tiered strategy of L1 soft derating, L2 controlled shutdown, and L3 physical isolation, differentiated response actions are executed according to the severity of the fault, avoiding unnecessary emergency shutdowns. In particular, when triggered at L2 level, a snapshot of the thermal equilibrium trajectory is recorded, saving key state parameters such as valve opening and liquid level. This provides the system with an initial PID bias value close to the stable operating condition for system reset and restart, thereby shortening the adjustment time required for the system to return to normal operation and reducing parameter fluctuations during the restart process. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings are used to provide a further understanding of the present invention.

[0050] Figure 1 This discloses a first frame schematic diagram of an embodiment of this application.

[0051] Figure 2 This discloses a second frame schematic diagram in an embodiment of this application.

[0052] Figure 3 This discloses a flowchart of an embodiment of this application. Detailed Implementation

[0053] The following is in conjunction with the appendix Figure 1 - Figure 3 A preferred description of the present invention is provided below.

[0054] See attached document Figure 1 - Figure 3 This invention proposes a safety and emergency switching system for electrolytic hydrogen production based on multi-level interlocking logic, comprising the following modules:

[0055] The data acquisition module is used to build a real-time data acquisition environment, collect electrical parameters, fluid parameters and actuator feedback status of the electrolytic cell system, and perform time synchronization processing to generate a basic operating status set.

[0056] The pressure prediction module, based on the basic operating state set, uses the bubble hysteresis compensation model to calculate the impact of bubbles generated by power fluctuations on system pressure, and generates a future pressure prediction vector that includes the pressure change trend within a future preset time window.

[0057] The discharge capacity calculation module, based on the valve status in the basic operating state set, calls the valve mechanical characteristic curve to obtain the flow coefficient of the pressure regulating valve under the current physical opening, and generates the mechanical response envelope characterizing the physical discharge capacity.

[0058] The logic comparison module compares the future pressure prediction vector with the mechanical response envelope in the time domain, and generates a power clamping lock signal to constrain the power regulation of the rectifier when the gas response mismatch is determined.

[0059] The hierarchical interlocking execution module, when the power clamping lock signal is activated, activates a hierarchical interlocking execution strategy, including L1 mode or L2 mode, based on the differential pressure convergence and gas concentration value in the basic operating state set.

[0060] In one embodiment of the present invention, the data acquisition module is configured to perform the following steps:

[0061] The high-frequency data acquisition module collects the output current and voltage values ​​of the rectifier and calculates the current change rate using a first-order backward differential algorithm. The process sensors collect the electrolytic cell outlet temperature, the real-time pressure value in the gas-liquid separator, and the liquid level height at the gas-liquid interface. The valve positioner reads the physical opening position of the pressure regulating valve and the valve action current feedback. The network time protocol client adds a unified timestamp to all the above-collected parameters and aggregates them into a structured data vector as the basic operating status set.

[0062] Specifically, the main entity executing this step is the central processing unit of the electrolysis hydrogen production system, which is typically integrated into a distributed control system (DCS) or a programmable logic controller (PLC). This central processing unit establishes real-time data communication links with various hardware modules deployed in the electrolyzer system via industrial fieldbus protocols such as Profibus-DP or Modbus-TCP.

[0063] First, the central processing unit sends a data read command to the high-frequency data acquisition module coupled to the DC output bus of the rectifier. This data acquisition module has a built-in Hall effect current sensor and a voltage divider sensor. It samples the output current and voltage values ​​of the rectifier at a preset electrical sampling frequency and packages the raw analog-to-digital conversion (AD) values ​​into data frames, which are then sent to the central processing unit. To address the signal distortion problem caused by aliasing in existing technologies, the electrical sampling frequency in this embodiment is set to 2 kHz to 5 kHz. This frequency is based on the Nyquist sampling theorem and covers the 100 Hz-500 Hz high-frequency components commonly found in renewable energy power fluctuations.

[0064] After receiving the continuous current data time series, the central processing unit executes a first-order backward difference algorithm to calculate the current change between adjacent sampling points, thereby obtaining the current change rate di / dt, which characterizes the severity of power fluctuations. It should be noted that this current change rate di / dt can be approximated by the following numerical differential formula:

[0065]

[0066] Among them, the rate of change of current It is obtained by numerically differentiating the time series of the output current value, and its unit is amperes per second (A / s). The formula... Represents the current moment The sampled current value, and This means that at the previous sampling time... The current value.

[0067] Meanwhile, the central processing unit polls various process sensors connected to the electrolyzer outlet pipe and the gas-liquid separator via the same bus. The sampling frequency is typically set to 10Hz to 50Hz, lower than electrical sampling because the time constant of the fluid thermodynamic process is large, usually on the order of seconds, and an excessively high sampling rate would lead to data redundancy. These sensors include: a resistance temperature sensor installed on the outlet manifold to obtain the electrolyzer outlet temperature; a 4-20 mA standard signal pressure transmitter installed on the top of the gas-liquid separator to obtain the real-time pressure value inside the gas-liquid separator; and a guided wave radar level gauge installed on the side wall of the gas-liquid separator to obtain the liquid level height at the gas-liquid interface. In addition, the central processing unit also communicates with the intelligent valve positioner of the pressure regulating valve that controls the hydrogen side back pressure, reading the valve position percentage signal representing the physical opening of the valve core as the physical opening position fed back by the positioner, and reading the current feedback value of the motor servo module that drives the valve as the valve action current feedback.

[0068] To ensure time consistency of all parameters, the central processing unit (CPU) runs a Network Time Protocol (NTP) client to synchronize with the system's master clock server. For example, the synchronization accuracy is controlled within 1 ms to eliminate phase differences between electrical and fluid data. Each received data packet or calculated result is timestamped with high precision. Finally, in a dedicated memory buffer, the CPU aggregates the timestamped output current, voltage, current change rate di / dt, electrolyzer outlet temperature, real-time pressure, gas-liquid interface level, physical opening position, and valve action current feedback into a structured data vector, generating a basic operating state set for subsequent steps. This basic operating state set is defined as a multi-data vector containing key operating parameters of the electrolyzer system at a specific timestamp, with the structure: [timestamp, output current, voltage, current change rate di / dt, electrolyzer outlet temperature, real-time pressure, gas-liquid interface level, physical opening position, valve action current feedback].

[0069] For example, suppose that within a certain work cycle, the central processing unit needs to generate a basic operating status set with a timestamp of 1678886410.000 seconds. First, the central processing unit sends a command to the rectifier data acquisition module via the industrial Ethernet interface to obtain the current time. The output current of the system is 5000 A, and the voltage is 400 V. Simultaneously, the system retrieves the previous sampling time from the historical data cache. The current value of s is 4980 A.

[0070] Subsequently, the central processing unit calculates the rate of change of current using the numerical differential formula. The calculation process is as follows: (5000 A - 4980 A) / (10.000 s - 9.998 s) = 20 A / 0.002 s = 10000 A / s. Within the same time window, the central processing unit polls the process sensors and reads that the electrolytic cell outlet temperature is 85℃, the real-time pressure in the gas-liquid separator is 3.0 MPa, and the liquid level at the gas-liquid interface is 55%.

[0071] Next, the central processing unit (CPU) reads from the valve positioner of the pressure regulating valve that its physical opening position is 40% and the operating current feedback is 1.2 A. Finally, the CPU binds all acquired and calculated data with the timestamp 1678886410.000, generates a basic operating state set for that moment in memory, specifically in the form of a data vector [1678886410.000,5000,400,10000,85,3.0,55,40,1.2], and stores this data vector in the shared data area for subsequent use.

[0072] It is worth mentioning that although this embodiment uses an alkaline electrolyzer as an example, the multi-level interlocking architecture and bubble hysteresis compensation concept of the present invention are also applicable to proton exchange membrane electrolysis hydrogen production systems or solid oxide electrolysis systems. Only the relevant parameters of bubble desorption delay time need to be adjusted according to the physical characteristics of the specific electrolyzer.

[0073] In one embodiment of the present invention, the pressure prediction module is configured to perform the following steps:

[0074] The system extracts real-time output current values, current change rate, and electrolyzer outlet temperature from the basic operating status. Based on Faraday's law of electrolysis, it calculates the baseline gas production rate using the real-time output current value. Simultaneously, based on the preset electrolyte-gas content function relationship, it calculates the incremental release of bubbles on the electrode surface caused by power fluctuations, and calculates the bubble desorption delay time in conjunction with the electrolyzer outlet temperature. Using the baseline gas production rate, bubble release increment, and bubble desorption delay time, combined with the physical volume parameters of the gas-liquid separator, it performs differential trend correction on the real-time pressure value and outputs a future pressure prediction vector.

[0075] Specifically, after acquiring the basic operating state set, the central processing unit immediately initiates the computational logic of the bubble hysteresis compensation model. The bubble hysteresis compensation model is an algorithm embedded within the central processing unit, the core of which lies in using a physical model for feedforward prediction.

[0076] First, the central processing unit accurately extracts the real-time output current value from the data vector of the basic operating state set according to the preset data structure index. Current change rate The three key input variables are the electrolyzer outlet temperature and the electrolyte. Next, the central processing unit calls upon the internally stored electrolyte-gas content function relationship. It should be understood that this function relationship is essentially a mathematical model pre-established through experimental calibration or fluid dynamics simulation, which characterizes the dynamic delay and gain relationship between the step change in current and the nucleation, growth, desorption of bubbles on the electrode surface, and the resulting measurable pressure change in the gas-liquid separator at a specific temperature.

[0077] The model is based on the rate of change of the input current. Based on the electrolytic cell outlet temperature, two key intermediate variables were calculated:

[0078] Bubble desorption delay time This parameter is not arbitrarily set, but is calculated based on the average rising velocity of bubbles in the electrolyte and the flow channel length. In this embodiment, for a typical alkaline electrolyzer, this delay time is negatively correlated with temperature, and the calculation formula is set as follows: Among them, the basic latency Set to 2.5s, based on calibration at 60℃; reference temperature Actual temperature These are values ​​collected in real time. Therefore, The value range is usually between 1.5 s and 4.0 s.

[0079] Bubble generation increment: the extra moles of gas per unit time caused by power fluctuations.

[0080] Subsequently, the central processing unit, combining the physical volume parameters of the gas-liquid separator read from the device configuration file (e.g., a gas phase space volume of 1.5 m³), ​​uses a variant of the ideal gas law to convert the incremental bubble generation into a predicted pressure rise slope. This process constitutes a differential trend correction to the real-time pressure value because it is not based on the current rate of change of pressure, but on the fundamental cause driving the pressure—the change in the gas production rate—thus anticipating the actual response of the physical pressure sensor. Specifically, the future pressure rise slope... The calculation can be represented by the following model:

[0081]

[0082]

[0083] In the formula, This is the real-time output current value of the rectifier at the current moment, in amperes. This is used to characterize the rate of pressure rise caused by a unit current of gas within the system volume. The setpoint is estimated based on the Faraday constant and the ideal gas equation, for example... ;

[0084] Delayed compensation It is used to characterize the pressure change caused by the transient release of bubbles due to a unit current change rate. It is a dimensionless temperature correction factor used to compensate for the effects of electrolyte temperature changes on gas volume and reaction kinetics; its form is defined as a linear function. ,in This is a temperature correction factor, typically set to 0.02 / ℃, based on Charles's Law and the characteristics of gas-liquid solubility changes. This is the reference temperature used during calibration. and The current change rate extracted from the basic operating state set, respectively. and the outlet temperature of the electrolytic cell.

[0085] Finally, the central processing unit calculates a future time based on this slope. Predicted pressure value :

[0086]

[0087] In the formula, It extracts the real-time pressure value at the current moment from the basic operational status set. The central processing unit encapsulates the calculated predicted pressure value and the pressure rise slope together into a new data structure, generating and outputting a future pressure prediction vector. The specific form of the future pressure prediction vector is as follows: .

[0088] For example, the central processing unit retrieves the aforementioned generated basic operating state set [1678886410.000,5000,400,10000,85,3.0,55,40,1.2]. First, the central processing unit extracts the real-time output current value from this dataset. for Current change rate The value is 10000 A / s, the outlet temperature of the electrolyzer is 85℃, and the real-time pressure value is... The pressure is 3.0 MPa. Next, the system reads the preset compensation model parameters from its configuration library: the baseline gas production coefficient. for Lag compensation coefficient for The reference temperature of the temperature correction function Temperature correction factor: 80℃ The value is 0.02 / ℃. Based on the current outlet temperature of 85℃, the system calls the bubble desorption delay time model to find the bubble desorption delay time under the current operating conditions. The time is 2.0 s. Subsequently, the central processing unit calculates the temperature correction factor. Then, substitute these values ​​into the formula to calculate the slope of the pressure rise. MPa / s. Based on this slope, the system further calculates the predicted future pressure value after 2.0 s. 2202 MPa. Ultimately, the system will calculate the future pressure value. 2202 MPa and pressure rise slope The MPa / s combination generates a future pressure prediction vector [3.000264, 0.000132], which is then output to a specified area in memory for use in subsequent steps.

[0089] In one embodiment of the present invention, the discharge capacity calculation module is used to perform the following steps:

[0090] Using the physical opening position of the basic operating state set as an index, the pre-stored valve mechanical characteristic curve is queried to obtain the flow coefficient of the pressure regulating valve at the current opening; based on the current physical opening position and the gas phase physical volume of the gas-liquid separator, the allowable pressure drop gradient of the system under the current pressure condition is calculated, and the pressure drop gradient is defined as the mechanical response envelope.

[0091] Specifically, the central processing unit initiates in parallel the processing flow for constructing the mechanical response envelope. This flow first analyzes the basic operating state set in real time and locates and extracts the current physical opening position of the pressure regulating valve from this dataset.

[0092] Subsequently, the central processing unit (CPU) uses this physical opening position as a query index to access the valve's pre-stored mechanical characteristic curve in its non-volatile memory. This curve is a pre-stored data file, such as a CSV lookup table, based on valve supplier data or experimental calibration, mapping the valve's physical opening position (0-100%) to multiple performance parameters. Through this query, the CPU obtains the flow coefficient and flow response delay corresponding to the pressure regulating valve at the current opening position; the flow coefficient... It characterizes the gas volumetric flow rate characteristics corresponding to a unit percentage opening under the current physical opening.

[0093] After obtaining the flow coefficient, the central processing unit further calls upon the valve flow characteristic parameters from the characteristic curve, along with the volume parameters of the gas-liquid separator already used, to perform physical model calculations. This calculation converts the maximum valve opening rate of change into the maximum gas mass outflow rate, and then derives the maximum rate of pressure decrease in the system under the current system pressure and volume conditions based on the gas state equation. The calculation result is the system's maximum physical release capacity at the current moment, and is dynamically defined as the mechanical response envelope, used to characterize the system's ultimate ability to actively reduce pressure through mechanical regulation.

[0094] It should be noted that the mechanical response envelope, i.e., the maximum pressure drop gradient, is... It can be calculated using the following formula:

[0095]

[0096] in, It is the valve flow characteristic coefficient, which characterizes the gas volume flow rate per unit opening degree, and its unit is... ; This refers to the current real-time pressure value obtained from the basic operational status database. This refers to the gas phase physical volume of the gas-liquid separator; this is a static configuration parameter. This represents the current physical opening position, taken from the basic operating state set, in units of %.

[0097] For example, the central processing unit processes the basic operating state set [1678886410.000,5000,400,10000,85,3.0,55,40,1.2] in parallel. First, the system extracts the physical opening position of 40% and the real-time pressure value. The pressure is 3.0 MPa. Next, the central processing unit retrieves the pre-stored valve mechanical characteristic curve to obtain the corresponding valve flow characteristic coefficient. for The system also obtains a corresponding flow response delay of 0.3 seconds. The system then reads the volume of the gas-liquid separator from the configuration file. It is 1.5 The central processing unit then substitutes these parameters into the formula to calculate the maximum pressure drop gradient. MPa / s. Finally, the central processing unit generates the mechanical response envelope, which at this moment has a specific value of 0.40 MPa / s. This value represents the maximum physical release capacity that the pressure regulation system can achieve under the current system state, and together with the 0.3 s flow response delay, it is cached in the high-speed data area for subsequent real-time time-domain comparison.

[0098] In one embodiment of the present invention, the logical comparison module is configured to perform the following steps:

[0099] Extract the pressure rise slope from the future pressure prediction vector and the pressure fall gradient from the mechanical response envelope; when the pressure rise slope exceeds the product of the pressure fall gradient and the preset safety margin coefficient, it is determined to be a gas response mismatch, and a power clamping lock signal for the first logic state is generated; the power clamping lock signal is mapped to the IGBT trigger unit of the rectifier to lock the rising edge of the PWM duty cycle and prevent the rectifier output current from increasing with the power command.

[0100] In the description of this invention, gas response mismatch refers to a critical state where the rate of pressure rise generated by the electrochemical reaction exceeds the maximum discharge rate that the physical valve can provide under the current condition. Existing technologies often neglect the dynamic comparison between these two factors in the time domain, while this invention establishes a constraint relationship between them by introducing the concept of a mechanical response envelope.

[0101] Specifically, the core of this step lies in the high-speed logic comparison engine running inside the central processing unit. This engine continuously and periodically executes reverse timing clamping logic. It should be understood that reverse timing clamping logic is a judgment mechanism that combines feedforward control and physical constraints, and its core is to compare the predicted system disturbance with the system's maximum adjustment capability.

[0102] First, the engine reads the future pressure prediction vector and the mechanical response envelope from memory, respectively. Specifically, it extracts the pressure rise slope from the future pressure prediction vector. and the maximum pressure drop gradient of the system defined by the mechanical response envelope. Subsequently, the central processing unit performs a real-time temporal domain projection comparison of the two slope values ​​generated under different physical models.

[0103] The central processing unit performs the following numerical comparison judgment:

[0104]

[0105] in As a safety margin factor, to prevent frequent actions under critical conditions, this embodiment sets... That is, when the predicted rate of pressure rise reaches 90% of the system's maximum discharge capacity, it is determined in advance that there is a mismatch in the gas response.

[0106] Once a gas turbine response mismatch is detected, the central processing unit immediately generates a high-level or logic 1 binary signal within the current instruction cycle, defined as a power clamping lock signal. This signal has the highest execution priority and can directly override conventional PID control or power scheduling instructions. This signal is directly mapped to the IGBT trigger unit controlling the rectifier's power output, i.e., the underlying drive circuit controlling the IGBT switches in the power electronic converter, via a dedicated hardware I / O channel or internal bus. At the hardware level, this signal acts on the logic gate circuit of the PWM signal generator, forcibly locking or limiting the rising edge drive signal of the PWM duty cycle. This means that even if the upper-level control system requests an increase in power, i.e., an increase in the PWM duty cycle, the PWM generator will ignore the instruction, thus physically preventing the rectifier's output current from continuing to increase with the instruction. This locked state will remain until the future pressure prediction vector, recalculated in a subsequent cycle, falls back to within the range defined by the mechanical response envelope, for example, below 80%, introducing a 10% hysteresis to prevent oscillation. Only then will the power clamping lock signal automatically release.

[0107] For example, following the previous steps, the logical comparison engine of the central processing unit at time... This step begins. First, it retrieves the future pressure prediction vector [3.2202, 0.1101] and extracts the pressure rise slope from it. The value is 0.1101 MPa / s. Simultaneously, it retrieves the mechanical response envelope, whose value is the maximum pressure drop gradient. The central processing unit makes comparisons and judgments, and discovers... much smaller Therefore, at this moment, the system determines that no turbine response mismatch has occurred, the power clamping lockout signal remains at logic 0 or low level, and the rectifier power regulation is normal. Assuming that in the next control cycle, due to a sudden increase in external wind power, the pressure rise slope in the recalculated future pressure prediction vector will... The pressure drops to 0.45 MPa / s, assuming drastic fluctuations in wind power, and the calculated maximum pressure drop gradient... Since the pressure and opening remain relatively constant at 0.40 MPa / s, a logic comparison engine is performed, revealing that 0.45 MPa / s is greater than 0.40 MPa / s. The system immediately determines that a gas turbine response mismatch has occurred. The central processing unit immediately generates a power clamping lockout signal and sets it to logic 1. This high-level signal is sent to the rectifier's control board via the digital output port. Assuming the rectifier's PWM duty cycle is currently 75%, and the upper-level power dispatch command requests it to increase to 80% to track wind power output, the rectifier's IGBT trigger unit will refuse to execute the command due to the power clamping lockout signal, forcibly locking the PWM duty cycle at 75%. This prevents the output current from increasing further, avoiding the risk of pressure overshoot. This locked state will persist until a future cycle, when the calculated... Falling back to Within the defined scope, for example The power clamping lock signal will automatically return to logic 0 only when the pressure drops to 0.14 MPa / s.

[0108] In one embodiment of the present invention, the hierarchical interlocking execution module is used to perform the following operations:

[0109] When the system is under power clamping lockout signal control, the actual pressure difference is calculated in real time. If the actual pressure difference does not converge within a preset time, the L1 level soft derating mode is triggered, reducing the rectifier current setpoint by a fixed step size while maintaining the circulating pump at full speed. The system also monitors the hydrogen-oxygen concentration and oxygen-hydrogen concentration in the basic operating state setpoint in real time. When either concentration value approaches the preset lower explosion limit threshold, the L2 level controlled shutdown mode is triggered. The execution logic of the L2 level controlled shutdown mode is as follows:

[0110] Send a rectifier shutdown command and simultaneously activate the delay counter; after the delay counter meets the preset cooling cycle, send commands in sequence to close the hydrogen side outlet valve and the oxygen side outlet valve to maintain positive pressure sealing of the system.

[0111] Specifically, this step is executed by a hierarchical interlocking logic controller deployed within the central processing unit. This controller continuously monitors the status of the power clamping lock signal and the basic operating state set, and executes the hierarchical interlocking execution strategy. It should be noted that the hierarchical interlocking execution strategy is a set of control logic that progressively escalates response actions based on the severity of the system state.

[0112] First, when the power clamping lock signal is activated and locked, the controller starts an internal timer and monitors the real-time pressure value of the basic operating status set. The actual pressure difference is obtained by calculating the difference between the current pressure and the target pressure setpoint. If this actual pressure difference fails to converge or continues to increase within a preset time (e.g., within 5 seconds, where the time setting is based on the system's typical pressure response time), the system determines that the clamping control has failed to effectively suppress pressure runaway and triggers the L1-level soft derating mode. The L1-level soft derating mode is an intervention measure that actively reduces system load without shutting down the system. In this mode, the central processing unit bypasses conventional power scheduling commands and directly sends a new, lower current setpoint to the rectifier. This value is gradually reduced in fixed steps; in this embodiment, the fixed step size is set to 5% of the rated current per second. For example, if the rated current is 6000 A, it is reduced by 300 A per second until the pressure difference begins to converge. Simultaneously, the electrolyte circulation pump controller receives a command to maintain full-speed operation to enhance heat and mass transfer within the system and prevent localized overheating.

[0113] Meanwhile, a separate, higher-priority safety monitoring process continuously monitors the hydrogen-oxygen concentration and oxygen-hydrogen concentration in the basic operating status database in real time. These two concentration values ​​are key indicators for measuring the safety of the electrolytic hydrogen production process. This process compares the real-time concentration values ​​with the lower explosive limit thresholds pre-stored in a configuration library. It should be noted that the lower explosive limit threshold is a legally defined critical value; for example, hydrogen in oxygen is approximately 4%, and to ensure safety, the trigger point is usually set at 25% to 50%. If either concentration value continues to rise and approaches this threshold, the system will immediately trigger the L2-level controlled shutdown mode. The L2-level controlled shutdown mode is an orderly, step-by-step shutdown procedure. In this mode, the central processing unit first sends an immediate shutdown command to the rectifier via a hardware relay or bus instruction. At the same time as sending this command, the system activates a separate hardware or software delay counter. This counter counts down according to the preset electrolyzer thermal inertia cooling cycle. Only after the delay counter has finished counting down will the central processing unit, according to a preset safety sequence, first send a command to close the outlet regulating valve on the hydrogen side. After confirmation that the valve is fully closed, it will then send a command to close the outlet valve on the oxygen side. This ensures that the system maintains a positive pressure seal throughout the shutdown and cooling process, preventing air backflow. The purpose of this delay counter is to ensure that the electrolyzer has sufficient time to cool down before the valves are shut off, avoiding equipment damage caused by localized overheating and pressure fluctuations.

[0114] For example, assuming the system has entered power clamping lockout signal control, the logic controller starts operating. First, the controller records the current real-time pressure as 3.1 MPa, while the setpoint is 3.0 MPa, the actual pressure difference is 0.1 MPa, and starts a 5-second timer. Within the 5 seconds of the timer, the controller detects that the real-time pressure changes successively to 3.12 MPa, 3.15 MPa, and 3.16 MPa, and the pressure difference has not converged.

[0115] Upon timer expiration, the system triggers the L1 level soft derating mode. Assuming the rectifier's rated current is 6000A and the current setpoint is 5000A, the controller lowers the setpoint by 300A in 5% increments, sending a new setpoint of 4700A to the rectifier and instructing it to maintain the circulating pump speed at 100%. During this process, the safety monitoring process continuously reads the basic operating status set, detecting an increase in oxygen concentration in hydrogen from 0.3%. When this concentration reaches 1.0%, since it has reached the preset lower explosive limit of 4% (25% trigger threshold), the system immediately triggers the L2 level controlled shutdown mode. The central processing unit immediately sends a disconnect command to the rectifier's main contactor, shutting it down.

[0116] Simultaneously, a 60-second delay counter is activated and begins its countdown. During these 60 seconds, the valve state remains unchanged, and the circulation pump continues to operate. When the delay counter counts down to 0, the central processing unit first sends a full-close command to the positioner of the hydrogen-side outlet valve. After receiving a signal indicating that the valve opening is 0%, it then sends a full-close command to the oxygen-side outlet valve, ultimately completing the entire controlled shutdown process.

[0117] In one embodiment of the present invention, the transient freeze module performs the following operations within the same instruction cycle that triggers the L2 level controlled shutdown mode: locks the basic operating state set at the trigger time and extracts the valve physical opening position, gas-liquid interface liquid level height and system pressure difference value; marks the extracted data as a thermal equilibrium trajectory snapshot and stores it as the initial bias value of the PID controller when the system is reset and started.

[0118] Specifically, this process is accomplished collaboratively by the event processing and data logging modules of the central processing unit (CPU), aiming to capture the last stable state before system failure. This process begins the instant the L2-level controlled shutdown mode is triggered. The trigger instant is precisely defined as the CPU scheduler responding to an interrupt indicating excessive oxygen concentration in hydrogen or oxygen concentration and switching the execution flow to the first machine instruction cycle of the L2-level shutdown procedure.

[0119] Within this instruction cycle, the central processing unit (CPU) employs atomic operations or high-priority tasks in parallel execution, for example, through the highest-priority interrupt service routine (ISR) of the real-time operating system (RTOS), simultaneously initiating two actions: the first action is sending a stop instruction to the rectifier. The second action, the core of this step, is performing a pre-fault transient freeze. The CPU accesses the memory address storing the most recently updated basic runtime state set and immediately locks that data block in read-only mode to prevent it from being corrupted or overwritten during subsequent shutdown procedures.

[0120] Next, the module extracts the physical opening position of the pressure regulating valve, the liquid level height at the gas-liquid interface of the gas-liquid separator, and the system differential pressure value calculated by the difference between the readings of the hydrogen and oxygen side pressure sensors, from the locked basic operating state set according to a preset data offset. This extracted data is then encapsulated into a new data structure with a specific identifier and marked by the system as a thermal equilibrium trajectory snapshot. The thermal equilibrium trajectory snapshot includes at least [valve opening value, liquid level height value, system differential pressure value], characterizing the quasi-steady-state equilibrium point reached by the system in terms of gas production, exhaust, and liquid level control just before the L2-level fault occurs.

[0121] Finally, the central processing unit calls the underlying driver to write this complete thermal equilibrium trajectory snapshot data block to a pre-designated non-volatile storage unit, such as an onboard EEPROM chip or a solid-state drive file on an industrial PC. This ensures that this critical status data is permanently preserved even after a complete system power failure. The main purpose of saving this snapshot is to use it as the initial bias value for the PID controller when the system recovers from a fault and restarts. Specifically, the valve opening value in the snapshot can be used as the initial output of the pressure PID controller, and the liquid level value can be used as the initial setting of the level PID controller. This significantly reduces the time for the PID controller to integrate from zero, achieving a fast and smooth system recovery.

[0122] For example, when the system detects that the oxygen concentration in hydrogen reaches 1.0% and triggers the L2 level controlled shutdown mode, assuming the trigger time is 1678886425.000, the central processing unit initiates two operations in parallel within the instruction cycle at this moment. The first operation is to send a shutdown command to the rectifier. The second operation, which is the implementation of this step, is to immediately lock the last valid basic operating state set before the trigger, i.e., the one with the timestamp 1678886424.998. Assume that the content of this dataset is [1678886424.998,4700,395,-15000,88,3.16,52,45,1.5], where the system pressure difference value is 0.01 MPa calculated based on the hydrogen-side pressure of 3.16 MPa and the oxygen-side pressure of 3.15 MPa in the basic operating state set. The data logging module then extracts key data from the dataset: the physical opening position is 45%, the gas-liquid interface level is 52%, and the system differential pressure is 0.01 MPa. Next, the system combines these three values ​​into a data packet, adds the header identifier "HBT_SNAPSHOT_L2", and generates a thermal equilibrium trajectory snapshot with the content {ID:"HBT_SNAPSHOT_L2",Valve:45,Level:52,DeltaP:0.01}. Finally, the central processing unit calls a memory write operation instruction to write this data structure as a byte stream to a specific address block of the onboard EEPROM, for example, the area starting at address 0x2F00. When the system needs to be reset and restarted in the future, the control program will first read the data in this address block and directly set the initial output value of the pressure PID controller to 45% and the initial feedback value of the level PID controller to 52%, thus enabling the system to start adjusting directly from a near-equilibrium state instead of starting from zero.

[0123] In one embodiment of the present invention, the emergency protection module is configured to perform the following steps:

[0124] When a fire detection signal or an external emergency stop hardwired signal is detected, the L3 physical isolation procedure is triggered. The bypass power clamping lock signal and the graded interlocking strategy physically disconnect the main circuit power supply to the rectifier and circulating pump, and trigger the de-energized closure of the pneumatic shut-off valve controlled by the safety instrument system. The L3 physical isolation procedure also includes: simultaneously opening the nitrogen purge valve upon triggering the closure of the pneumatic shut-off valve, using high-pressure nitrogen to physically isolate and replace residual gas in the hydrogen and oxygen side pipelines; continuously monitoring the gas concentration detection value at the end of the pipeline, and only allowing the nitrogen purge valve to close when the gas concentration detection value is lower than the preset safety limit.

[0125] Specifically, this step is executed by a safety instrumented system controller embedded in the control system hardware or a separate controller, which has the highest execution priority. It should be understood that the safety instrumented system is a protection layer independent of the basic process control system, designed in accordance with functional safety standards such as IEC 61508 / 61511, and possesses independent sensors and actuators. This process is executed by the safety instrumented system, which is independent of the process control system. The two interact through hardwiring or a secure communication protocol to ensure that, in the event of control system failure, Level 3 protection still has the highest execution authority, complying with the design requirements of the IEC 61508 functional safety standard.

[0126] The logic continuously monitors two highest-priority external input signals in parallel: one is a hardwired signal from flame or smoke detectors deployed in critical areas such as the electrolyzer room and hydrogen compressor room; the other is a hardwired signal from the emergency stop button at the operator station or on-site. These signals are typically 24V DC hardwired circuits with extremely high reliability. Once either signal is triggered, for example, by changing from a normally closed contact to an open state, the signal will directly act on the main control logic via a hardware interrupt. At this time, the system immediately performs a bypass operation, that is, at the hardware level, through logic gates or safety relays, forcibly disconnecting the output path of the software control signals. This means that all software-implemented control logic, including power clamping lockout signals and L1 and L2 interlocking strategies, will be forcibly ignored or skipped.

[0127] Immediately following, the safety controller issues a high-priority physical disconnect command. This command, via a separate, safety-certified relay output module, directly disconnects the high-voltage circuit breaker supplying power to the rectifier's main circuit and the main circuit power supply to the motor contactors powering all electrolyte circulation pumps, achieving complete energy isolation. Within the same logic cycle executing the electrical disconnect, the safety controller also triggers a critical action in the safety instrumented system (VIS). The VIS controls the air supply solenoid valves to depressurize the compressed air supply to the pneumatic shut-off valve actuators. These pneumatic valves, acting as final protection elements, possess fail-safe characteristics and automatically close upon loss of air supply, relying on spring reset, thereby quickly and physically isolating the inlet and outlet pipelines of the electrolyzer.

[0128] Simultaneously, the safety instrumented system (VIS) activates the nitrogen purging valve connected to the high-pressure nitrogen source. High-pressure nitrogen then flows into the hydrogen and oxygen pipelines isolated by the shut-off valve. This creates a physical barrier between the electrolyzer and the external piping network, preventing gas backflow. Furthermore, continuous purging removes residual hydrogen and oxygen from the pipelines. This nitrogen purging process continues until the gas concentration monitoring instruments at the end of the pipelines show values ​​below preset safety limits, such as a hydrogen concentration below 0.1%, which is far below the lower explosive limit. Only then does the safety logic allow the purging to stop, marking the completion of the entire L3-level physical isolation and inert gas replacement process.

[0129] For example, suppose that during system operation, a flame detector located above the electrolyzer is triggered due to abnormal infrared radiation. The detector's output relay contacts switch from closed to open, causing the voltage in the 24V DC hardwired circuit connected to the SIS controller input module to change from 24V to 0V. The SIS controller hardware immediately detects this change and generates a highest-priority interrupt. This interrupt triggers L3 level logic. First, all executing L1 / L2 level software logic is masked. The safety instrumented controller simultaneously issues commands to multiple execution units through its redundant digital output modules. Command 1 de-energizes the trip coil of the vacuum circuit breaker in the rectifier's 6 kV incoming cabinet, causing the circuit breaker to trip and disconnect the rectifier's main power supply. Command 2 de-energizes the contactor coils controlling the three circulating pump motors, causing the pump motors to stop operating. Command 3 de-energizes the gas source solenoid valves controlling the DN200 pneumatic shut-off valves on the hydrogen and oxygen side outlet mains, causing the valves to fully close within 2 seconds under spring force. Command 4 energizes and opens the solenoid valve of the DN50 nitrogen purging valve on the main nitrogen line. Subsequently, high-pressure nitrogen at 0.8 MPa is injected into the hydrogen and oxygen lines respectively. Nitrogen purging continues, and the gas analyzer located on the vent line continuously monitors the concentration. After 90 seconds of purging, the hydrogen concentration decreased from the initial 99% to 0.08%, and the oxygen concentration decreased from 98% to 0.5%. Since both values ​​are below the preset safety limit of 0.1%, the safety instrumented system determines that the purging is complete and automatically closes the nitrogen purging valve. However, other equipment remains isolated, awaiting manual inspection and reset.

[0130] Each of the modules can be implemented in whole or in part through software, hardware, or a combination thereof. It supports hardware embedded in or independent of the processor in the computer device, and also supports software stored in the memory of the computer device, so that the processor can call and execute the operations corresponding to each of the above modules.

[0131] 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, and should all be included within the protection scope of the present invention.

Claims

1. A safety and emergency switching system for hydrogen production via electrolysis based on multi-level interlocking logic, characterized in that, include: The data acquisition module is used to build a real-time data acquisition environment, collect electrical parameters, fluid parameters and actuator feedback status of the electrolytic cell system, and perform time synchronization processing to generate a basic operating status set. The pressure prediction module, based on the basic operating state set, uses the bubble hysteresis compensation model to calculate the impact of bubbles generated by power fluctuations on system pressure, and generates a future pressure prediction vector that includes the pressure change trend within a future preset time window. The discharge capacity calculation module, based on the valve status in the basic operating state set, calls the valve mechanical characteristic curve to obtain the flow coefficient of the pressure regulating valve under the current physical opening, and generates the mechanical response envelope characterizing the physical discharge capacity. The logic comparison module compares the future pressure prediction vector with the mechanical response envelope in the time domain, and generates a power clamping lock signal to constrain the power regulation of the rectifier when the gas response mismatch is determined. The hierarchical interlocking execution module, when the power clamping lock signal is activated, activates a hierarchical interlocking execution strategy, including L1 mode or L2 mode, based on the differential pressure convergence and gas concentration value in the basic operating state set.

2. The electrolytic hydrogen production safety and emergency switching system based on multi-level interlocking logic according to claim 1, characterized in that, The data acquisition module is used to perform the following operations: The output current and voltage values ​​of the rectifier are acquired by a high-frequency data acquisition module, and the current change rate is calculated using a first-order backward differential algorithm. The electrolyzer outlet temperature, the real-time pressure value in the gas-liquid separator, and the liquid level height at the gas-liquid interface are collected by process sensors. The physical opening position of the pressure regulating valve and the valve action current feedback are read through the valve positioner. The Network Time Protocol client is used to assign a unified timestamp to all the parameters collected above, and these parameters are aggregated into a structured data vector as the basic running status set.

3. The electrolytic hydrogen production safety and emergency switching system based on multi-level interlocking logic according to claim 1, characterized in that, The pressure prediction module is used to perform the following steps: Real-time output current value, current change rate and electrolytic cell outlet temperature are extracted from the basic operating status. Based on Faraday's law of electrolysis, the reference gas production rate is calculated using the real-time output current value. At the same time, based on the preset electrolyte gas content function relationship, the incremental release of bubbles on the electrode surface caused by power fluctuations is calculated, and the bubble desorption delay time is calculated in combination with the electrolytic cell outlet temperature. By using the baseline gas production rate, bubble release increment, and bubble desorption delay time, combined with the physical volume parameters of the gas-liquid separator, the real-time pressure value is modified by differential trend correction, and a future pressure prediction vector is output.

4. The electrolytic hydrogen production safety and emergency switching system based on multi-level interlocking logic according to claim 1, characterized in that, The discharge capacity calculation module is used to perform the following steps: Using the physical opening position of the basic operating status set as an index, query the pre-stored valve mechanical characteristic curve to obtain the flow coefficient of the pressure regulating valve at the current opening. Based on the current physical opening position and the gas phase physical volume of the gas-liquid separator, the allowable pressure drop gradient of the system under the current pressure conditions is calculated, and the pressure drop gradient is defined as the mechanical response envelope.

5. The electrolytic hydrogen production safety and emergency switching system based on multi-level interlocking logic according to claim 1, characterized in that, The logical comparison module is used to perform the following operations: Extract the pressure rise slope from the future pressure prediction vector and the pressure fall gradient from the mechanical response envelope; When the pressure rise slope exceeds the product of the pressure fall gradient and the preset safety margin coefficient, it is determined to be a gas turbine response mismatch, and a power clamping lock signal for the first logic state is generated. The power clamping signal is mapped to the IGBT trigger unit of the rectifier to lock the rising edge of the PWM duty cycle and prevent the rectifier output current from increasing with the power command.

6. The electrolytic hydrogen production safety and emergency switching system based on multi-level interlocking logic according to claim 1, characterized in that, The hierarchical interlocking execution module is used to perform the following operations: When the system is under the control of the power clamping lock signal, the actual pressure difference is calculated in real time. If the actual pressure difference does not converge within the preset time, the L1 level soft derating mode is triggered, the rectifier current setting value is reduced by a fixed step size and the circulating pump is kept running at full speed. Real-time monitoring of the concentration of oxygen in hydrogen and the concentration of hydrogen in oxygen in the basic operating status; When any concentration value approaches the preset lower explosion limit threshold, the L2 level controlled shutdown mode is triggered.

7. The electrolytic hydrogen production safety and emergency switching system based on multi-level interlocking logic according to claim 6, characterized in that, The execution logic of the L2 controlled shutdown mode is as follows: Send a rectifier shutdown command and simultaneously activate the delay counter; After the delay counter meets the preset cooling cycle, commands are sent sequentially to close the hydrogen-side outlet valve and the oxygen-side outlet valve to maintain positive pressure sealing of the system.

8. The electrolytic hydrogen production safety and emergency switching system based on multi-level interlocking logic according to claim 7, characterized in that, It also includes a transient freeze module, which performs the following operations within the same instruction cycle that triggers the L2 level controlled shutdown mode: Lock the basic operating state set at the trigger moment, and extract the valve physical opening position, gas-liquid interface liquid level height and system pressure difference value from it; The captured data is marked as a thermal equilibrium trajectory snapshot and stored as the initial bias value of the PID controller when the system is reset and started.

9. The electrolytic hydrogen production safety and emergency switching system based on multi-level interlocking logic according to claim 1, characterized in that, It also includes an emergency protection module for performing the following steps: When a fire detection signal or an external emergency stop hardwired signal is detected, the L3 physical isolation process is triggered. The bypass power clamping lock signal and the hierarchical interlocking execution strategy physically disconnect the main circuit power supply of the rectifier and the circulating pump, and trigger the pneumatic shut-off valve controlled by the safety instrument system to close due to power failure.

10. The electrolytic hydrogen production safety and emergency switching system based on multi-level interlocking logic according to claim 9, characterized in that, Level 3 physical isolation procedures also include: At the same time as triggering the pneumatic shut-off valve to close, the nitrogen purging valve is opened in conjunction with the high-pressure nitrogen to physically isolate and replace residual gas in the hydrogen-side pipeline and oxygen-side pipeline. Continuously monitor the gas concentration at the end of the pipeline, and only allow the nitrogen purging valve to be closed when the gas concentration is lower than the preset safety limit.

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