A control method for a hydrogen production control system with adaptive low-power stable operation

Abstract

The present invention discloses a self-adaptive low-power stable operation hydrogen production control system and method thereof, including a hydrogen side gas-liquid separator, an oxygen side gas-liquid separator, a hydrogen side scrubber, an oxygen side scrubber, a hydrogen side cooler, an oxygen side cooler and an electrolyzer; the hydrogen outlet of the electrolyzer is connected to the air inlet of the hydrogen side gas-liquid separator, and its oxygen outlet is connected to the air inlet of the oxygen side gas-liquid separator; the air outlet of the hydrogen side gas-liquid separator is connected to the air inlet of the hydrogen side scrubber, and the air outlet of the hydrogen side scrubber is connected to a channel inlet of the hydrogen side cooler through a hydrogen side regulating valve, and the channel outlet of the hydrogen side cooler is connected to a gas storage tank; the air outlet of the oxygen side gas-liquid separator is connected to the air inlet of the oxygen side scrubber, and the air outlet of the oxygen side scrubber is connected to a channel inlet of the oxygen side cooler through an oxygen side regulating valve, and the channel outlet of the oxygen side cooler is connected to the outside. The present invention expands the load range of the hydrogen production control system to improve its stable operation time under low load.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen production by alkaline water electrolysis, and in particular to a control method for a self-adaptive low-power stable operation hydrogen production control system. Background Art

[0002] As important technical solutions to achieve the strategic goals of "carbon peak and carbon neutrality", renewable energy such as solar energy, wind energy and tidal energy have been widely deployed and developed by countries around the world. However, the generation of renewable energy such as solar energy and wind energy depends on factors such as season, climate, geographical location and time. Therefore, renewable energy generation is volatile, intermittent and seasonal. As the proportion of wind power and photovoltaic power in power generation continues to grow, the changes in power generation surplus and shortage may expand from hourly or daily to seasonal time scales. Solving the seasonal changes of renewable energy means that different degrees of flexibility resources are needed in the power system throughout the year, and hydrogen energy is considered to be one of the key paths to solve the problem of renewable energy absorption due to its various advantages such as high energy density, cleanliness and storage.

[0003] At present, alkaline water electrolyzer (AWE) and proton exchange membrane water electrolyzer (PEMEC) are considered to be technologies that can produce hydrogen on a large scale in the market; however, due to the mature technology, large production capacity and low investment cost of AWE, AWE is more competitive than PEMEC. However, due to the volatility of renewable energy power generation, especially when the power supply is relatively low (such as 20-35% of the rated power), the AWE hydrogen production system will operate at a low current density, and hydrogen will more easily enter the oxygen side, causing the hydrogen concentration in oxygen (HTO) of the electrolyzer system to exceed the safe range (below 2%), and the AWE hydrogen production system will automatically alarm and shut down for safety; so this minimum load limit hinders the efficiency and service life of the AWE hydrogen production system.

[0004] In order to solve the safety problem of the AWE hydrogen production system at low load, it is crucial to reduce the HTO of the AWE hydrogen production system at low current density. The research results show that hydrogen-oxygen crosstalk is formed through two processes: 1) The first process is the transmission of hydrogen from the cathode to the anode through the ion diaphragm, and the diffusion amount is determined by factors such as the physical properties of the ion diaphragm, the current density, the alkali solution flow rate and the pressure; 2) The second process occurs in the gas-liquid separator and the pipeline, where the electrolytes from the cathode and the anode are mixed, and part of the hydrogen and oxygen dissolved in the electrolyte remain in the electrolyte after passing through the gas-liquid separator. It can be seen that in both processes, pressure plays a decisive role in the HTO of the AWE hydrogen production system; compared with oxygen, hydrogen is easier to diffuse through the separator, which causes the HTO to increase with increasing pressure, especially under low current density operating conditions. In addition, for the second process, according to Henry's law, if the pressure increases, the solubility of the gas in the liquid will also increase, that is, high pressure will lead to an increase in HTO.

[0005] The traditional AWE hydrogen production system basically uses the classic PID control method to adjust the HTO of the AWE hydrogen production system (for example, the Chinese patents with publication numbers CN 117144416 A and CN 117187878 A). Active disturbance rejection control (ADRC) is a predictable control technology that does not rely on the system model. It can track the system output value, estimate and compensate for the internal and external disturbances of the system in real time, and realize load disturbance rejection. Compared with the traditional PID control method, ADRC has a wide range of controlled objects, flexible control quantity combinations, and excellent anti-interference ability. Therefore, how to develop a new type of AWE hydrogen production control system and hydrogen production control method with self-disturbance rejection and low-load operation, and maintain continuous and stable operation within the safety range of the system and under low load, has become a difficult problem that needs to be solved urgently. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a control method for a hydrogen production control system with adaptive low-power stable operation, so as to expand the load range of the hydrogen production control system and increase its stable operation time under low load.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions: A control method of a hydrogen production control system with adaptive low-power stable operation of the present invention, its innovation lies in: its hydrogen production control system includes a hydrogen side gas-liquid separator, an oxygen side gas-liquid separator, a hydrogen side scrubber, an oxygen side scrubber, a hydrogen side cooler, an oxygen side cooler, a hydrogen side regulating valve, an oxygen side regulating valve, an electrolyzer and a gas storage tank; the hydrogen outlet of the electrolyzer is connected to the air inlet on one side of the hydrogen side gas-liquid separator through a pipeline, and its oxygen outlet is connected to the air inlet on one side of the oxygen side gas-liquid separator through a pipeline; the top air outlet of the hydrogen side gas-liquid separator is connected to the top air inlet of the hydrogen side scrubber through a pipeline. The top gas outlet of the oxygen side gas-liquid separator is connected with the top gas inlet of the oxygen side scrubber through a pipeline, and the side gas outlet of the oxygen side scrubber is connected with the channel inlet of the hydrogen side cooler through a pipeline via a hydrogen side regulating valve, and the channel outlet of the hydrogen side cooler is connected with the gas storage tank, and the hydrogen after double separation is subjected to heat exchange and cooling through the hydrogen side cooler, and is stored in the gas storage tank; the top gas outlet of the oxygen side gas-liquid separator is connected with the top gas inlet of the oxygen side scrubber through a pipeline, and the side gas outlet of the oxygen side scrubber is connected with the channel inlet of the oxygen side cooler through a pipeline via an oxygen side regulating valve, and the channel outlet of the oxygen side cooler is connected with the outside through a pipeline, and the oxygen after double separation is subjected to heat exchange and cooling through the oxygen side cooler;

[0008] It also includes a raw water tank, a water supply pump, a circulation pump, a check valve II, a check valve III, a check valve IV, a heat exchanger, a radiator and a filter; the raw water tank is connected to the bottom water inlet of the hydrogen side scrubber and the bottom water inlet of the oxygen side scrubber through a pipeline through a water supply pump, and a check valve IV is also provided on the pipeline connecting the water supply pump and the hydrogen side scrubber, and a check valve III is also provided on the pipeline connecting the water supply pump and the oxygen side scrubber, thereby ensuring that the water injected into the hydrogen side scrubber and the oxygen side scrubber will not flow back; one side water outlet of the hydrogen side scrubber is connected to one side water inlet of the hydrogen side gas-liquid separator through a pipeline, and one side of the oxygen side scrubber The water outlet is connected to a water inlet on one side of the oxygen-side gas-liquid separator through a pipeline; the bottom water outlet of the hydrogen-side gas-liquid separator and the bottom water outlet of the oxygen-side gas-liquid separator are respectively connected to a channel inlet of the heat exchanger through pipelines, and the outlet of a channel of the heat exchanger is connected to the bottom of the electrolyzer through a pipeline in sequence through a filter, a circulation pump and a check valve II, thereby recovering excess alkali liquid in the hydrogen-side scrubber, the hydrogen-side gas-liquid separator, the oxygen-side scrubber and the oxygen-side gas-liquid separator into the electrolyzer, and in this process, the temperature of the recovered excess alkali liquid is maintained at 90° C. through the heat exchange effect of the heat exchanger, and the recovered excess alkali liquid is filtered through a filter;

[0009] It also includes a check valve I, an alkali adding tank, a check valve V, a check valve VI, a hydrogen side flow meter and an oxygen side flow meter; the alkali adding tank is connected to the inlet end of the circulation pump through a pipeline via the check valve I, and the check valve I ensures that the excess alkali solution filtered by the filter is recovered into the electrolytic cell through the circulation pump; a check valve V is also provided on the pipeline connecting the oxygen side regulating valve and the oxygen side cooler, and a check valve VI is also provided on the pipeline connecting the hydrogen side regulating valve and the hydrogen side cooler, thereby avoiding the occurrence of backflow; a hydrogen side flow meter is also provided on the pipeline connecting the hydrogen side cooler and the gas storage tank, and an oxygen side flow meter is also provided on the pipeline connecting the oxygen side cooler and the outside;

[0010] It also includes a radiator, a cooling water tank and a cooling water pump; the water outlet of the cooling water tank is connected to a channel inlet of the hydrogen side gas-liquid separator, a channel inlet of the oxygen side gas-liquid separator, a channel inlet of the hydrogen side scrubber, a channel inlet of the oxygen side scrubber, a channel inlet of the hydrogen side cooler, a channel inlet of the oxygen side cooler and another channel inlet of the heat exchanger through a pipeline through the cooling water pump, and a channel outlet of the hydrogen side gas-liquid separator, a channel outlet of the oxygen side gas-liquid separator, a channel outlet of the hydrogen side scrubber, a channel outlet of the oxygen side scrubber, a channel outlet of the hydrogen side cooler, a channel outlet of the oxygen side cooler and another channel outlet of the heat exchanger are connected to the water inlet of the cooling water tank through a pipeline through the radiator, and then heat exchange and cooling are performed in the hydrogen side gas-liquid separator, the oxygen side gas-liquid separator, the hydrogen side scrubber, the oxygen side scrubber, the hydrogen side cooler and the oxygen side cooler respectively through cooling water, and the heated cooling water is cooled through the radiator and then sent to the cooling water tank, forming a cycle;

[0011] It also includes a pressure gauge I, a hydrogen side liquid level meter, an oxygen side liquid level meter and an oxygen-hydrogen detector; the hydrogen side gas-liquid separator is also provided with a pressure gauge I for detecting the internal pressure thereof, and a hydrogen side liquid level meter for detecting the internal liquid level thereof is also provided thereon; the oxygen side gas-liquid separator is also provided with an oxygen side liquid level meter for detecting the internal liquid level thereof, and a oxygen-hydrogen detector for detecting the concentration of hydrogen in oxygen is also provided at the top gas outlet thereof; the hydrogen side scrubber is also provided with a pressure gauge II for detecting the internal pressure thereof, and the oxygen side scrubber is also provided with a pressure gauge III for detecting the internal pressure thereof, and the pressure difference between the hydrogen side scrubber and the oxygen side scrubber is obtained by the cooperation of the pressure gauge II and the pressure gauge III;

[0012] The hydrogen production control method includes the following steps:

[0013] Step 1: First, the water in the raw water tank is pumped into the hydrogen side scrubber and the oxygen side scrubber through the water supply pump, and then enters the hydrogen side gas-liquid separator and the oxygen side gas-liquid separator respectively, and then comes out from the bottom water outlet of the hydrogen side gas-liquid separator and the oxygen side gas-liquid separator respectively, first enters the heat exchanger for heat exchange to maintain the temperature of 90°C, then enters the filter for filtration, and finally is recovered to the electrolyzer through the circulation pump;

[0014] Step 2: The cooling water pump then pumps the cooling water in the cooling water tank into the hydrogen side gas-liquid separator, the oxygen side gas-liquid separator, the hydrogen side scrubber, the oxygen side scrubber, the hydrogen side cooler, the oxygen side cooler and the heat exchanger for heat exchange, and then cools the water through the radiator and returns it to the cooling water tank to form a cycle;

[0015] Step 3: Then the hydrogen production control system starts to run and completes initialization, and the pressure is controlled by the initial hydrogen side regulating valve opening; the electrolyzer produces hydrogen and oxygen under direct current electrolysis, wherein,

[0016] The hydrogen first enters the hydrogen side gas-liquid separator for primary gas-liquid separation, and in this process, it exchanges heat with cooling water for cooling, and the excess alkali liquid is brought back to the electrolyzer through water; then, the hydrogen after the primary gas-liquid separation enters the hydrogen side scrubber for secondary gas-liquid separation, and in this process, it exchanges heat with cooling water for cooling, and the excess alkali liquid is brought back to the electrolyzer through water; then, the hydrogen after the secondary gas-liquid separation enters the hydrogen side cooler for heat exchange with cooling water for cooling, and is stored in the gas storage tank;

[0017] The oxygen first enters the oxygen side gas-liquid separator for primary gas-liquid separation, and in this process, it exchanges heat with the cooling water for cooling, and the excess alkali solution is brought back to the electrolytic cell through the water; then, the oxygen after the primary gas-liquid separation enters the oxygen side scrubber for secondary gas-liquid separation, and in this process, it exchanges heat with the cooling water for cooling, and the excess alkali solution is brought back to the electrolytic cell through the water; then, the oxygen after the secondary gas-liquid separation enters the oxygen side cooler for heat exchange with the cooling water for cooling, and is discharged or stored for use according to the user's usage;

[0018] Step 4: Collect data in real time through pressure gauges I, II and III, and record the pressure changes of the hydrogen production control system; at the same time, collect real-time data values ​​of hydrogen concentration in oxygen through the hydrogen-in-oxygen detector, and use the self-disturbance rejection controller to identify and determine whether it exceeds the safety limit of 1.8% of hydrogen concentration in oxygen. If it does not exceed, continue to operate with the current hydrogen side regulating valve opening; if it exceeds, adjust the opening of the hydrogen side regulating valve through the self-disturbance rejection controller to reduce the hydrogen concentration in oxygen until the hydrogen concentration in oxygen is maintained below 1.8%.

[0019] Preferably, in the above step four, the crossover of hydrogen and oxygen in the hydrogen production control system includes diffusion through the diaphragm, convection crossover and gas crossover through circulating electrolyte mixing, and based on the crossover mechanism of hydrogen and oxygen, a dynamic accumulation model of hydrogen concentration in oxygen is constructed, and then the sudden change of load current is used as the external disturbance input of the hydrogen production control system, the pressure of the hydrogen production control system is used as the internal disturbance, and the pressure of the hydrogen side gas-liquid separator is used as the controlled quantity, and then the opening of the hydrogen side regulating valve is dynamically adjusted by the self-disturbance rejection controller to ensure the stable operating pressure of the hydrogen production control system under working conditions and reduce the degree of hydrogen and oxygen cross-talk.

[0020] Preferably, in the above step 4, since there is no need to track the differentiator to output the differential signal, the active disturbance rejection controller consists of two parts: an extended state observer and a nonlinear state error feedback control law; wherein,

[0021] The extended state observer is the core link of the ADRC. It regards nonlinearity, parameter uncertainty, and external disturbances as extended states, observes disturbances, and uses feedforward links to compensate for them. The second-order extended state observer uses the output of the controlled object as the y and the control quantity of the active disturbance rejection controller u As input, the various state variables and internal and external disturbances of the hydrogen production control system are estimated, so that the control ability of the active disturbance rejection controller is enhanced; its expression is:

[0022] ;

[0023] In the formula, z 1. z 2 are the two state variables of the extended state observer; β 01 , β 02 is the error adjustment gain of the extended state observer; b is the compensation factor; fal It is a nonlinear discrete function with fast convergence characteristics and good filtering effect on input noise; e is the error between the safety limit value of hydrogen concentration in oxygen and the real-time data value of hydrogen concentration in oxygen; α is the tracking factor; δ is the filtering factor; sgn is a step function;

[0024] The nonlinear state error feedback control law integrates the error signals generated by the tracking differentiator and the extended state observer through nonlinear functions, and finally obtains the controlled quantity of the active disturbance rejection controller. u The nonlinear controller is:

[0025] ;

[0026] In the formula, v 0 is the safe limit of hydrogen concentration in oxygen; v1 is the input signal after arranging the transition process; h is the discrete control period of the ADRC, i.e., the sampling period; β is the proportional coefficient of the feedback control law.

[0027] Preferably, β 01 , β 02 Determined by the discrete control period of the ADRC, β 01 =1 / h, β 02 =1 / (5h2); compensation factor b Determines the compensation control capability of the ADRC and the proportional coefficient of the feedback control law β It will affect the hysteresis performance of the disturbance estimation value of the hydrogen production control system. b The smaller or β The larger the value, the stronger the control ability, the smaller the lag, the faster the response speed, and the stronger the robustness of the system, but the overshoot will also increase accordingly; so when the hydrogen concentration in oxygen exceeds the safety limit of 1.8% of hydrogen concentration in oxygen, the fuzzy controller first determines the compensation factor b and the respective increments Δ of the proportional coefficient β of the feedback control law b , Δ β , and then the extended state observer and the nonlinear state error feedback control law in the anti-disturbance controller are used to apply disturbances to the pressure of the hydrogen production control system, that is, the valve opening of the hydrogen-side regulating valve is adjusted to reduce the hydrogen concentration in oxygen, until the hydrogen concentration in oxygen is maintained below 1.8%, and then the current valve opening of the hydrogen-side regulating valve is maintained unchanged, thereby controlling the hydrogen concentration in oxygen to be below the safety limit value of the hydrogen concentration in oxygen.

[0028] Beneficial effects of the present invention:

[0029] (1) The present invention expands the load range of the hydrogen production control system to increase its stable operation time under low load;

[0030] (2) The present invention optimizes the system pressure of the hydrogen production control system when it is running under low load in real time based on the real-time data value of the hydrogen concentration in oxygen, based on the anti-disturbance controller and combined with the fuzzy controller, and reduces the gas crossover through the diaphragm and the gas crossover caused by the mixing of the circulating electrolyte by reducing the system pressure, thereby reducing the minimum load. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1The figure is a connection diagram of a self-adaptive low-power stable operation hydrogen production control system of the present invention.

[0033] Figure 2 This is a flow chart of the self-disturbance rejection control of hydrogen concentration in oxygen according to the present invention.

[0034] Figure 3 It is a structural diagram of the active disturbance rejection controller of the present invention.

[0035] Figure 4 It is the structural diagram of the fuzzy controller of the present invention.

[0036] Figure 5 This is the structural diagram of the optimized fuzzy-ADR controller of the present invention.

[0037] Figure 6 For the present invention Δ b / Δ β Fuzzy control law table.

[0038] Among them, 1-electrolyzer; 2-hydrogen side gas-liquid separator; 3-oxygen side gas-liquid separator; 4-hydrogen side scrubber; 5-oxygen side scrubber; 6-hydrogen side cooler; 7-oxygen side cooler; 8-raw material water tank; 9-alkali adding tank; 10-cooling water tank; 11-radiator; 12-check valve I; 13-circulation pump; 14-hydrogen side regulating valve; 15-oxygen side regulating valve; 16-hydrogen side liquid level meter; 17-oxygen side liquid level meter; 18-pressure gauge I; 19-hydrogen side flow meter; 20-oxygen side flow meter; 21-check valve II; 22-gas storage tank; 23-check valve III; 24-check valve IV; 25-check valve V; 26-check valve VI; 27-heat exchanger; 28-filter; 29-water supply pump; 30-cooling water pump. DETAILED DESCRIPTION

[0039] The technical solution of the present invention will be clearly and completely described below through specific implementation methods.

[0040] The present invention provides an adaptive low-power stable operation hydrogen production control system, comprising a hydrogen side gas-liquid separator 2, an oxygen side gas-liquid separator 3, a hydrogen side scrubber 4, an oxygen side scrubber 5, a hydrogen side cooler 6, an oxygen side cooler 7, a hydrogen side regulating valve 14, an oxygen side regulating valve 15, an electrolyzer 1 and a gas storage tank 22; the specific structure is as follows Figure 1As shown, the hydrogen outlet of the electrolyzer 1 is communicated with the air inlet on one side of the hydrogen-side gas-liquid separator 2 through a pipeline, and its oxygen outlet is communicated with the air inlet on one side of the oxygen-side gas-liquid separator 3 through a pipeline; the top air outlet of the hydrogen-side gas-liquid separator 2 is communicated with the top air inlet of the hydrogen-side scrubber 4 through a pipeline, and the air outlet on one side of the hydrogen-side scrubber 4 is communicated with the one-channel inlet of the hydrogen-side cooler 6 through a pipeline via a hydrogen-side regulating valve 14, the one-channel outlet of the hydrogen-side cooler 6 is communicated with the gas storage tank 22, and the hydrogen after double separation is subjected to heat exchange cooling through the hydrogen-side cooler 6 and stored in the gas storage tank 22; the top air outlet of the oxygen-side gas-liquid separator 3 is communicated with the top air inlet of the oxygen-side scrubber 5 through a pipeline, and the air outlet on one side of the oxygen-side scrubber 5 is communicated with the one-channel inlet of the oxygen-side cooler 7 through a pipeline via an oxygen-side regulating valve 15, the one-channel outlet of the oxygen-side cooler 7 is communicated with the outside through a pipeline, and the oxygen after double separation is subjected to heat exchange cooling through the oxygen-side cooler 7.

[0041] The raw water tank 8 of the present invention is connected to the bottom water inlet of the hydrogen side scrubber 4 and the bottom water inlet of the oxygen side scrubber 5 through a pipeline via a water supply pump 29, and a check valve IV 24 is provided on the pipeline connecting the water supply pump 29 and the hydrogen side scrubber 4, and a check valve III 23 is provided on the pipeline connecting the water supply pump 29 and the oxygen side scrubber 5, thereby ensuring that the water injected into the hydrogen side scrubber 4 and the oxygen side scrubber 5 will not flow back; Figure 1 As shown, one side water outlet of the hydrogen side scrubber 4 is connected to one side water inlet of the hydrogen side gas-liquid separator 2 through a pipeline, and one side water outlet of the oxygen side scrubber 5 is connected to one side water inlet of the oxygen side gas-liquid separator 3 through a pipeline; the bottom water outlet of the hydrogen side gas-liquid separator 2 and the bottom water outlet of the oxygen side gas-liquid separator 3 are respectively connected to a channel inlet of the heat exchanger 27 through pipelines, and a channel outlet of the heat exchanger 27 is connected to the bottom of the electrolyzer 1 through a pipeline in sequence through the filter 28, the circulation pump 13 and the check valve II 21, thereby recovering the excess alkali liquid in the hydrogen side scrubber 4, the hydrogen side gas-liquid separator 2, the oxygen side scrubber 5 and the oxygen side gas-liquid separator 3 into the electrolyzer 1, and in this process, the temperature of the recovered excess alkali liquid is maintained at 90°C through the heat exchange effect of the heat exchanger 27, and the recovered excess alkali liquid is filtered through the filter 28.

[0042] like Figure 1As shown, the alkali adding tank 9 is connected to the inlet end of the circulation pump 13 through a pipeline via a check valve I 12, and the check valve I 12 ensures that the excess alkali solution filtered by the filter 28 is recovered into the electrolytic cell 1 through the circulation pump 13; a check valve V 25 is also provided on the pipeline connecting the oxygen side regulating valve 15 and the oxygen side cooler 7, and a check valve VI 26 is also provided on the pipeline connecting the hydrogen side regulating valve 14 and the hydrogen side cooler 6, thereby avoiding the occurrence of backflow; a hydrogen side flowmeter 19 is also provided on the pipeline connecting the hydrogen side cooler 6 and the gas storage tank 22, and an oxygen side flowmeter 20 is also provided on the pipeline connecting the oxygen side cooler 7 and the outside.

[0043] like Figure 1 As shown, the water outlet of the cooling water tank 10 is connected to a channel inlet of the hydrogen side gas-liquid separator 2, a channel inlet of the oxygen side gas-liquid separator 3, a channel inlet of the hydrogen side scrubber 4, a channel inlet of the oxygen side scrubber 5, a channel inlet of the hydrogen side cooler 6, a channel inlet of the oxygen side cooler 7 and another channel inlet of the heat exchanger 27 through a pipeline through a cooling water pump 30, and a channel outlet of the hydrogen side gas-liquid separator 2, a channel outlet of the oxygen side gas-liquid separator 3, a channel outlet of the hydrogen side scrubber 4, an oxygen side scrubber 5, a channel outlet of the hydrogen side cooler 6, a channel outlet of the oxygen side cooler 7 and another channel outlet of the heat exchanger 27 are respectively connected with the water inlet of the cooling water tank 10 through pipelines via the radiator 11, and then heat exchange and cooling are performed in the hydrogen side gas-liquid separator 2, the oxygen side gas-liquid separator 3, the hydrogen side scrubber 4, the oxygen side scrubber 5, the hydrogen side cooler 6 and the oxygen side cooler 7 through cooling water, and the heated cooling water is cooled down through the radiator 11 and then sent to the cooling water tank 10 to form a cycle.

[0044] like Figure 1 As shown, a pressure gauge Ⅰ18 for detecting the internal pressure is also provided on the hydrogen side gas-liquid separator 2, and a hydrogen side liquid level meter 16 for detecting the internal liquid level is also provided on it; an oxygen side liquid level meter 17 for detecting the internal liquid level is also provided on the oxygen side gas-liquid separator 3, and a hydrogen-in-oxygen detector for detecting the concentration of hydrogen in oxygen is also provided at the top gas outlet; a pressure gauge Ⅱ for detecting the internal pressure is also provided on the hydrogen side scrubber 4, and a pressure gauge Ⅲ for detecting the internal pressure is also provided on the oxygen side scrubber 5, and the pressure difference between the hydrogen side scrubber 4 and the oxygen side scrubber 5 is obtained by the cooperation of the pressure gauge Ⅱ and the pressure gauge Ⅲ.

[0045] The present invention provides a hydrogen production control method for a hydrogen production control system with adaptive low power stable operation, such as Figures 1 to 6 As shown, the following steps are included:

[0046] Step 1: First, the water in the raw water tank 8 is pumped into the hydrogen side scrubber 4 and the oxygen side scrubber 5 through the water replenishment pump 29, and then enters the hydrogen side gas-liquid separator 2 and the oxygen side gas-liquid separator 3 respectively, and then comes out from the bottom water outlet of the hydrogen side gas-liquid separator 2 and the oxygen side gas-liquid separator 3 respectively, first enters the heat exchanger 27 for heat exchange to maintain a temperature of 90°C, and then enters the filter 28 for filtration, and finally is recovered to the electrolytic cell 1 through the circulation pump 13.

[0047] Step 2: Then the cooling water pump 30 pumps the cooling water in the cooling water tank 10 into the hydrogen side gas-liquid separator 2, the oxygen side gas-liquid separator 3, the hydrogen side scrubber 4, the oxygen side scrubber 5, the hydrogen side cooler 6, the oxygen side cooler 7 and the heat exchanger 27 for heat exchange, and then cools the cooling water through the radiator 11 and returns it to the cooling water tank 10 to form a cycle.

[0048] Step 3: Then the hydrogen production control system starts to run and completes initialization, and the pressure is controlled by the initial opening of the hydrogen side regulating valve 14; the electrolyzer 1 produces hydrogen and oxygen under the electrolysis of direct current, wherein,

[0049] The hydrogen first enters the hydrogen side gas-liquid separator 2 for primary gas-liquid separation, and in this process, heat exchange is performed with cooling water for cooling, and the excess alkali solution is brought back to the electrolytic cell 1 through water; then, the hydrogen after the primary gas-liquid separation enters the hydrogen side scrubber 4 for secondary gas-liquid separation, and in this process, heat exchange is performed with cooling water for cooling, and the excess alkali solution is brought back to the electrolytic cell 1 through water; then, the hydrogen after the secondary gas-liquid separation enters the hydrogen side cooler 6 for heat exchange with cooling water for cooling, and is stored in the gas storage tank 22;

[0050] The oxygen first enters the oxygen side gas-liquid separator 3 for primary gas-liquid separation, and in this process, it exchanges heat with the cooling water for cooling, and the excess alkali liquid is brought back to the electrolytic cell 1 through the water; then, the oxygen after the primary gas-liquid separation enters the oxygen side scrubber 5 for secondary gas-liquid separation, and in this process, it exchanges heat with the cooling water for cooling, and the excess alkali liquid is brought back to the electrolytic cell 1 through the water; then, the oxygen after the secondary gas-liquid separation enters the oxygen side cooler 7 for heat exchange with the cooling water for cooling, and is discharged or stored for use according to the user's usage.

[0051] Step 4: Collect data in real time through pressure gauge I 18, pressure gauge II and pressure gauge III, and record the pressure changes of the hydrogen production control system; at the same time, collect real-time data values ​​of hydrogen concentration in oxygen through the hydrogen-in-oxygen detector, and identify and determine whether it exceeds the safety limit value of hydrogen concentration in oxygen of 1.8% through the self-disturbance rejection controller. If it does not exceed, continue to operate with the current opening of the hydrogen side regulating valve 14; if it exceeds, adjust the opening of the hydrogen side regulating valve 14 through the self-disturbance rejection controller to reduce the hydrogen concentration in oxygen until the hydrogen concentration in oxygen is maintained below 1.8%.

[0052] In the above steps, the crossover of hydrogen and oxygen in the hydrogen production control system includes diffusion through the diaphragm, convection crossover and gas crossover through circulating electrolyte mixing, and based on the crossover mechanism of hydrogen and oxygen, a dynamic accumulation model of hydrogen concentration in oxygen is constructed, and then the sudden change of load current is used as the external disturbance input of the hydrogen production control system, the pressure of the hydrogen production control system is used as the internal disturbance, and the pressure of the hydrogen side gas-liquid separator 2 is used as the controlled quantity, and then the opening of the hydrogen side regulating valve 14 is dynamically adjusted by the self-disturbance rejection controller to ensure the stable operating pressure of the hydrogen production control system under working conditions, reduce the degree of hydrogen and oxygen cross-talk, and ensure the realization of low load to adapt to the fluctuating and intermittent renewable energy power generation.

[0053] Since the present invention does not need a tracking differentiator (TD) to output the differential signal, the ADRC consists of two parts: an extended state observer (ESO) and a nonlinear state error feedback control law (NLSEF).

[0054] The extended state observer is the core link of the ADRC. It regards nonlinearity, parameter uncertainty, and external disturbances as extended states, observes disturbances, and uses feedforward links to compensate for them. The second-order extended state observer uses the output of the controlled object as the y and the control quantity of the active disturbance rejection controller u As input, the various state variables and internal and external disturbances of the hydrogen production control system are estimated, so that the control ability of the active disturbance rejection controller is enhanced; its expression is:

[0055] ;

[0056] In the formula, z 1. z 2 are the two state variables of the extended state observer; β 01 , β 02 is the error adjustment gain of the extended state observer; b is the compensation factor; fal It is a nonlinear discrete function with fast convergence characteristics and good filtering effect on input noise; e is the error between the safety limit value of hydrogen concentration in oxygen and the real-time data value of hydrogen concentration in oxygen; α is the tracking factor; δ is the filtering factor; sgn is a step function;

[0057] The nonlinear state error feedback control law integrates the error signals generated by the tracking differentiator and the extended state observer through nonlinear functions, and finally obtains the controlled quantity of the active disturbance rejection controller. uThe nonlinear controller is:

[0058] ;

[0059] In the formula, v 0 is the safe limit of hydrogen concentration in oxygen; v 1 is the input signal after arranging the transition process; h is the discrete control period of the ADRC, i.e., the sampling period; β is the proportional coefficient of the feedback control law.

[0060] Compared with the conventional active disturbance rejection controller, the present invention cancels the tracking differentiator link, and adopts a linear algorithm instead of a traditional nonlinear algorithm for the extended state observer and the nonlinear state error feedback control law, so that the control adjustment parameters in the active disturbance rejection controller are greatly reduced, the real-time performance is enhanced, and the control performance is improved.

[0061] Among them, β 01 , β 02 Determined by the discrete control period of the ADRC, β 01 =1 / h, β 02 =1 / (5h2); compensation factor b Determines the compensation control capability of the ADRC and the proportional coefficient of the feedback control law β It will affect the hysteresis performance of the disturbance estimation value of the hydrogen production control system. b The smaller or β The larger the value, the stronger the control ability, the smaller the lag, the faster the response speed, and the stronger the robustness of the system, but the overshoot will also increase accordingly; so when the hydrogen concentration in oxygen exceeds the safety limit of 1.8% of hydrogen concentration in oxygen, the fuzzy controller first determines the compensation factor b and the respective increments Δ of the proportional coefficient β of the feedback control law b , Δ β , and then the extended state observer and the nonlinear state error feedback control law in the anti-disturbance controller are used to apply disturbances to the pressure of the hydrogen production control system, that is, the valve opening of the hydrogen-side regulating valve 14 is adjusted to reduce the hydrogen concentration in oxygen, until the hydrogen concentration in oxygen is maintained below 1.8%, and then the current valve opening of the hydrogen-side regulating valve 14 is maintained unchanged, thereby controlling the hydrogen concentration in oxygen to be below the safety limit value of the hydrogen concentration in oxygen.

[0062] The fuzzy controller of the present invention learns the dynamic relationship between the system and the outside through fuzzy reasoning, outputs the fuzzified input value as a clear value, and has strong fault tolerance and adaptability; the fuzzy controller includes three parts: fuzzy domain, fuzzy rules, and membership function; specifically:

[0063] (a) Fuzzification of input and output variables and determination of membership function

[0064] The input of the fuzzy controller is the error between the safety limit value of hydrogen concentration in oxygen and the real-time data value of hydrogen concentration in oxygen. e , and its derivative ; Compensation factor b and the respective increments Δ of the proportional coefficient β of the feedback control law b , Δ β As the output of the fuzzy controller; Figure 4 , Figure 5 As shown, k1 and k2 are input gain factors; k3 and k4 are output gain factors; e, The basic domains corresponding to the fuzzy rules mapped by k1 and k2 are all [-6, 6], Δ b , Δ β The basic domains of are [-1, 1], [-0.5, 0.5]; if e and If the variation range of exceeds the basic domain, the output value is adjusted by adjusting k1 and k2; the membership function of input and output selects a triangular function with higher sensitivity.

[0065] (b) Fuzzy rules and fuzzy reasoning

[0066] Seven fuzzy subsets are set on the fuzzy domain: {NB, NM, NS, ZO, PS, PM, PB}, and the meaning of each element is: negative large, negative medium, negative small, zero, positive small, positive medium, positive large. Based on the accumulation of professional knowledge and operating experience, according to the adjustment rules of each parameter, it can be obtained that Δ b , Δ β The fuzzy control rule selection table is as follows: Figure 6 As shown; when e and If it is large, Δ should be reduced b Or increase Δ β The value of can speed up the system response and improve the dynamic performance; when e and When it is small, Δ should be increased b Or reduce Δ β To reduce the disturbance of the system response, the present invention first debugs the initial value of the parameter based on the experience of technicians and literature in order to reduce the calculation amount of the controller. b =50, β =0.1, and then adjust the correction parameters according to the fuzzy rules.

[0067] Fuzzy reasoning uses Mamdani-type reasoning that is easy to represent graphically, and the fuzzy value is obtained by the centroid method (weighted average method) with smoothed output:

[0068] ;

[0069] In the formula, f is the clear value; m cis the membership degree; T * is a fuzzy set; q is the number of elements in the fuzzy set.

[0070] Then the optimized gain can be obtained as:

[0071] ;

[0072] The fuzzy controller of the present invention has the advantages of self-tuning parameters and improving the stability and accuracy of the system. The present invention utilizes fuzzification processing and fuzzy logic reasoning to obtain fuzzy quantities. The correction parameters of the final defuzzified output will self-adjust within a limited range of variation and automatically approach the optimal value, thus making up for the shortcomings of the self-disturbance rejection controller in parameter tuning.

[0073] Beneficial effects of the present invention:

[0074] (1) The present invention expands the load range of the hydrogen production control system to increase its stable operation time under low load;

[0075] (2) The present invention optimizes the system pressure of the hydrogen production control system when it is running under low load in real time based on the real-time data value of the hydrogen concentration in oxygen, based on the anti-disturbance controller and combined with the fuzzy controller, and reduces the gas crossover through the diaphragm and the gas crossover caused by the mixing of the circulating electrolyte by reducing the system pressure, thereby reducing the minimum load.

[0076] The embodiments described above are merely descriptions of preferred implementation modes of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary engineering technicians in the field should fall within the protection scope of the present invention. The technical contents for which protection is sought in the present invention have been fully recorded in the technical requirements.

Claims

1. A control method for a hydrogen production control system with adaptive low-power stable operation, characterized in that: The hydrogen production control system comprises a hydrogen side gas-liquid separator, an oxygen side gas-liquid separator, a hydrogen side scrubber, an oxygen side scrubber, a hydrogen side cooler, an oxygen side cooler, a hydrogen side regulating valve, an oxygen side regulating valve, an electrolyzer and a gas storage tank; the hydrogen outlet of the electrolyzer is connected to an air inlet on one side of the hydrogen side gas-liquid separator through a pipeline, and the oxygen outlet is connected to an air inlet on one side of the oxygen side gas-liquid separator through a pipeline; the top air outlet of the hydrogen side gas-liquid separator is connected to the top air inlet of the hydrogen side scrubber through a pipeline, and the air outlet on one side of the hydrogen side scrubber is connected to the air inlet on the hydrogen side scrubber through a pipeline via the hydrogen side regulating valve. A channel inlet of the hydrogen side cooler is connected, a channel outlet of the hydrogen side cooler is connected to the gas storage tank, and the hydrogen after double separation is cooled by heat exchange through the hydrogen side cooler and stored in the gas storage tank; the top air outlet of the oxygen side gas-liquid separator is connected to the top air inlet of the oxygen side scrubber through a pipeline, and a side air outlet of the oxygen side scrubber is connected to a channel inlet of the oxygen side cooler through a pipeline via an oxygen side regulating valve, a channel outlet of the oxygen side cooler is connected to the outside through a pipeline, and the oxygen after double separation is cooled by heat exchange through the oxygen side cooler; It also includes a raw water tank, a water supply pump, a circulation pump, a check valve II, a check valve III, a check valve IV, a heat exchanger, a radiator and a filter; the raw water tank is connected to the bottom water inlet of the hydrogen side scrubber and the bottom water inlet of the oxygen side scrubber through a pipeline through a water supply pump, and a check valve IV is also provided on the pipeline connecting the water supply pump and the hydrogen side scrubber, and a check valve III is also provided on the pipeline connecting the water supply pump and the oxygen side scrubber, thereby ensuring that the water injected into the hydrogen side scrubber and the oxygen side scrubber will not flow back; one side water outlet of the hydrogen side scrubber is connected to one side water inlet of the hydrogen side gas-liquid separator through a pipeline, and one side of the oxygen side scrubber The water outlet is connected to a water inlet on one side of the oxygen-side gas-liquid separator through a pipeline; the bottom water outlet of the hydrogen-side gas-liquid separator and the bottom water outlet of the oxygen-side gas-liquid separator are respectively connected to a channel inlet of the heat exchanger through pipelines, and the outlet of a channel of the heat exchanger is connected to the bottom of the electrolyzer through a pipeline in sequence through a filter, a circulation pump and a check valve II, thereby recovering excess alkali liquid in the hydrogen-side scrubber, the hydrogen-side gas-liquid separator, the oxygen-side scrubber and the oxygen-side gas-liquid separator into the electrolyzer, and in this process, the temperature of the recovered excess alkali liquid is maintained at 90° C. through the heat exchange effect of the heat exchanger, and the recovered excess alkali liquid is filtered through a filter; It also includes a check valve I, an alkali adding tank, a check valve V, a check valve VI, a hydrogen side flow meter and an oxygen side flow meter; the alkali adding tank is connected to the inlet end of the circulation pump through a pipeline via the check valve I, and the check valve I ensures that the excess alkali solution filtered by the filter is recovered into the electrolytic cell through the circulation pump; a check valve V is also provided on the pipeline connecting the oxygen side regulating valve and the oxygen side cooler, and a check valve VI is also provided on the pipeline connecting the hydrogen side regulating valve and the hydrogen side cooler, thereby avoiding the occurrence of backflow; a hydrogen side flow meter is also provided on the pipeline connecting the hydrogen side cooler and the gas storage tank, and an oxygen side flow meter is also provided on the pipeline connecting the oxygen side cooler and the outside; It also includes a radiator, a cooling water tank and a cooling water pump; the water outlet of the cooling water tank is connected to a channel inlet of the hydrogen side gas-liquid separator, a channel inlet of the oxygen side gas-liquid separator, a channel inlet of the hydrogen side scrubber, a channel inlet of the oxygen side scrubber, a channel inlet of the hydrogen side cooler, a channel inlet of the oxygen side cooler and another channel inlet of the heat exchanger through a pipeline through the cooling water pump, and a channel outlet of the hydrogen side gas-liquid separator, a channel outlet of the oxygen side gas-liquid separator, a channel outlet of the hydrogen side scrubber, a channel outlet of the oxygen side scrubber, a channel outlet of the hydrogen side cooler, a channel outlet of the oxygen side cooler and another channel outlet of the heat exchanger are connected to the water inlet of the cooling water tank through a pipeline through the radiator, and then heat exchange and cooling are performed in the hydrogen side gas-liquid separator, the oxygen side gas-liquid separator, the hydrogen side scrubber, the oxygen side scrubber, the hydrogen side cooler and the oxygen side cooler respectively through cooling water, and the heated cooling water is cooled through the radiator and then sent to the cooling water tank, forming a cycle; It also includes a pressure gauge I, a hydrogen side liquid level meter, an oxygen side liquid level meter and an oxygen-hydrogen detector; the hydrogen side gas-liquid separator is also provided with a pressure gauge I for detecting the internal pressure thereof, and a hydrogen side liquid level meter for detecting the internal liquid level thereof is also provided thereon; the oxygen side gas-liquid separator is also provided with an oxygen side liquid level meter for detecting the internal liquid level thereof, and a oxygen-hydrogen detector for detecting the concentration of hydrogen in oxygen is also provided at the top gas outlet thereof; the hydrogen side scrubber is also provided with a pressure gauge II for detecting the internal pressure thereof, and the oxygen side scrubber is also provided with a pressure gauge III for detecting the internal pressure thereof, and the pressure difference between the hydrogen side scrubber and the oxygen side scrubber is obtained by the cooperation of the pressure gauge II and the pressure gauge III; The hydrogen production control method is characterized by comprising the following steps: Step 1: First, the water in the raw water tank is pumped into the hydrogen side scrubber and the oxygen side scrubber through the water supply pump, and then enters the hydrogen side gas-liquid separator and the oxygen side gas-liquid separator respectively, and then comes out from the bottom water outlet of the hydrogen side gas-liquid separator and the oxygen side gas-liquid separator respectively, first enters the heat exchanger for heat exchange to maintain the temperature of 90°C, then enters the filter for filtration, and finally is recovered to the electrolyzer through the circulation pump; Step 2: The cooling water pump then pumps the cooling water in the cooling water tank into the hydrogen side gas-liquid separator, the oxygen side gas-liquid separator, the hydrogen side scrubber, the oxygen side scrubber, the hydrogen side cooler, the oxygen side cooler and the heat exchanger for heat exchange, and then cools the water through the radiator and returns it to the cooling water tank to form a cycle; Step 3: Then the hydrogen production control system starts to run and completes initialization, and the pressure is controlled by the initial hydrogen side regulating valve opening; the electrolyzer produces hydrogen and oxygen under direct current electrolysis, wherein, The hydrogen first enters the hydrogen side gas-liquid separator for primary gas-liquid separation, and in this process, it exchanges heat with cooling water for cooling, and the excess alkali liquid is brought back to the electrolyzer through water; then, the hydrogen after the primary gas-liquid separation enters the hydrogen side scrubber for secondary gas-liquid separation, and in this process, it exchanges heat with cooling water for cooling, and the excess alkali liquid is brought back to the electrolyzer through water; then, the hydrogen after the secondary gas-liquid separation enters the hydrogen side cooler for heat exchange with cooling water for cooling, and is stored in the gas storage tank; The oxygen first enters the oxygen side gas-liquid separator for primary gas-liquid separation, and in this process, it exchanges heat with the cooling water for cooling, and the excess alkali solution is brought back to the electrolytic cell through the water; then, the oxygen after the primary gas-liquid separation enters the oxygen side scrubber for secondary gas-liquid separation, and in this process, it exchanges heat with the cooling water for cooling, and the excess alkali solution is brought back to the electrolytic cell through the water; then, the oxygen after the secondary gas-liquid separation enters the oxygen side cooler for heat exchange with the cooling water for cooling, and is discharged or stored for use according to the user's usage; Step 4: Collect data in real time through pressure gauges I, II and III, and record the pressure changes of the hydrogen production control system; at the same time, collect real-time data values ​​of hydrogen concentration in oxygen through the hydrogen-in-oxygen detector, and use the self-disturbance rejection controller to identify and determine whether it exceeds the safety limit of 1.8% of hydrogen concentration in oxygen. If it does not exceed, continue to operate with the current hydrogen side regulating valve opening; if it exceeds, adjust the opening of the hydrogen side regulating valve through the self-disturbance rejection controller to reduce the hydrogen concentration in oxygen until the hydrogen concentration in oxygen is maintained below 1.8%.

2. The control method of a hydrogen production control system with adaptive low-power stable operation according to claim 1 is characterized in that: In the above step four, the crossover of hydrogen and oxygen in the hydrogen production control system includes diffusion through the diaphragm, convection crossover and gas crossover through circulating electrolyte mixing, and based on the crossover mechanism of hydrogen and oxygen, a dynamic accumulation model of hydrogen concentration in oxygen is constructed, and then the sudden change of load current is used as the external disturbance input of the hydrogen production control system, the pressure of the hydrogen production control system is used as the internal disturbance, and the pressure of the hydrogen side gas-liquid separator is used as the controlled quantity, and then the opening of the hydrogen side regulating valve is dynamically adjusted through the self-disturbance rejection controller to ensure the stable operating pressure of the hydrogen production control system under working conditions and reduce the degree of hydrogen and oxygen cross-talk.

3. The control method of a hydrogen production control system with adaptive low-power stable operation according to claim 2 is characterized in that: In the above step 4, since there is no need to track the differentiator to output the differential signal, the ADRC consists of two parts: the extended state observer and the nonlinear state error feedback control law; among them, The extended state observer is the core link of the ADRC. It regards nonlinearity, parameter uncertainty, and external disturbances as extended states, observes disturbances, and uses feedforward links to compensate for them. The second-order extended state observer uses the output of the controlled object as the y and the control quantity of the active disturbance rejection controller u As input, the various state variables and internal and external disturbances of the hydrogen production control system are estimated, so that the control ability of the active disturbance rejection controller is enhanced; its expression is: ； In the formula, z 1. z 2 are the two state variables of the extended state observer; β 01 , β 02 is the error adjustment gain of the extended state observer; b is the compensation factor; fal It is a nonlinear discrete function with fast convergence characteristics and good filtering effect on input noise; e is the error between the safety limit value of hydrogen concentration in oxygen and the real-time data value of hydrogen concentration in oxygen; α is the tracking factor; δ is the filtering factor; sgn is a step function; The nonlinear state error feedback control law integrates the error signals generated by the tracking differentiator and the extended state observer through nonlinear functions, and finally obtains the controlled quantity of the active disturbance rejection controller. u The nonlinear controller is: ； In the formula, v 0 is the safe limit of hydrogen concentration in oxygen; v 1 is the input signal after arranging the transition process; h is the discrete control period of the ADRC, i.e., the sampling period; β is the proportional coefficient of the feedback control law.

4. The control method of a hydrogen production control system with adaptive low-power stable operation according to claim 3 is characterized in that: β 01 , β 02 Determined by the discrete control period of the ADRC, β 01 =1 / h, β 02 =1 / (5h 2 ); Compensation factor b Determines the compensation control capability of the ADRC and the proportional coefficient of the feedback control law β It will affect the hysteresis performance of the disturbance estimation value of the hydrogen production control system. b The smaller or β The larger the value, the stronger the control ability, the smaller the lag, the faster the response speed, and the stronger the robustness of the system, but the overshoot will also increase accordingly; so when the hydrogen concentration in oxygen exceeds the safety limit of 1.8% of hydrogen concentration in oxygen, the fuzzy controller first determines the compensation factor b and the respective increments Δ of the proportional coefficient β of the feedback control law b , Δ β , and then the extended state observer and the nonlinear state error feedback control law in the anti-disturbance controller are used to apply disturbances to the pressure of the hydrogen production control system, that is, the valve opening of the hydrogen-side regulating valve is adjusted to reduce the hydrogen concentration in oxygen, until the hydrogen concentration in oxygen is maintained below 1.8%, and then the current valve opening of the hydrogen-side regulating valve is maintained unchanged, thereby controlling the hydrogen concentration in oxygen to be below the safety limit value of the hydrogen concentration in oxygen.

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