Method for adjusting local operating power of multiple network-forming electrolytic cell parallel systems

Abstract

The application provides a method for adjusting local operation power of a plurality of networked electrolytic cell systems, comprising: obtaining an actual value of a current state factor of a local electrolytic cell; wherein the local electrolytic cell is any electrolytic cell in the plurality of networked electrolytic cell systems, and the actual value of the current state factor is used to determine a safe operation range of the local electrolytic cell; based on the actual value of the current state factor of the local electrolytic cell, determining and adjusting an operation mode of the local electrolytic cell; if the operation mode of the local electrolytic cell is a network control mode, obtaining a dynamic rated value of a current state factor transmitted on a communication bus of the plurality of networked electrolytic cell systems; and based on the dynamic rated value of the current state factor, adjusting the operation power of the local electrolytic cell. The application can achieve power balance among a plurality of electrolytic cell groups when the network side power changes, and enhance the support for system voltage and frequency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power coordination in network construction, and in particular to the adjustment of the operating power of electrolytic cells in network construction structures. BACKGROUND

[0002] Hydrogen production is becoming increasingly important in new power systems, and has significant advantages in enhancing new energy consumption, energy storage, and providing peak shaving services, promoting energy interconnection, etc. (Characteristics of electrolytic cells) Electrolytic cells are the core equipment in the production of hydrogen production systems, and their interface converters and control systems are the key to realizing hydrogen production by water electrolysis. Compared with traditional energy conversion equipment, electrolytic cells exhibit many advantages, which support their application and development in the hydrogen energy industry.

[0003] Existing control of electrolytic hydrogen production systems is divided into two levels: single and parallel multi-body. The control around the single electrolytic cell is mainly developed in the grid-connected type, that is, the electrolytic cell is used as a power-adjustable load to respond to the power fluctuations of renewable energy sources such as photovoltaic and wind turbines. The combination of these two characteristics can smooth the fluctuations of renewable energy in grid-connected state or directly consume in off-grid state. The voltage-voltage characteristics of electrolytic cells are ignored, and the network support capability of electrolytic cells is not fully tapped. The method around the parallel multi-body electrolytic cell generally uses the wheel value command optimization method to control the rated power operation and shutdown of the electrolytic cell. To some extent, it alleviates the power imbalance phenomenon, but it does not fully tap the characteristics of each single body and real-time complementary operating state of the electrolytic cell array. The output of the electrolytic cell is handled in a rough and simple manner, and the working condition division is simple. The adjustment characteristics of the alkaline electrolytic cell, the number of start-stop times, and the safety of hydrogen production are not considered enough, which affects the service life of the electrolytic cell. SUMMARY

[0004] The present application provides a system and method for adjusting the operating power of local electrolytic cells based on a network construction system to solve the problems mentioned in the prior art.

[0005] To achieve the above purpose, the present application also provides a method for adjusting the local operating power of a plurality of network construction type electrolytic cell parallel systems, comprising:

[0006] Obtain the current state factor actual value of the local electrolytic cell; wherein the local electrolytic cell is any electrolytic cell in the plurality of network construction type electrolytic cell parallel systems, and the current state factor actual value is used to determine the safe operating range of the local electrolytic cell;

[0007] Based on the current state factor actual value of the local electrolytic cell, the operating mode of the local electrolytic cell is determined and adjusted;

[0008] If the operation mode of the local electrolyzer is a grid-connected control mode, a dynamic rating value of a current state factor transmitted on a communication bus of a plurality of grid-connected electrolyzers and a system is acquired;

[0009] Based on the dynamic rating value of the current state factor, the operation power of the local electrolyzer is adjusted.

[0010] Optionally, the adjustment of the operation mode of the local electrolyzer based on the actual value of the current state factor of the local electrolyzer comprises:

[0011] Based on the actual value of the current state factor of the local electrolyzer, it is judged whether the actual value of the current state factor of the local electrolyzer is within a preset range of a safe operation current state factor of the local electrolyzer, and the operation mode of the local electrolyzer is adjusted according to the judgment result;

[0012] If yes, the operation mode of the local electrolyzer is adjusted to a grid-connected control mode;

[0013] If no, the local electrolyzer is adjusted to operate in a first or second constant power control mode.

[0014] Optionally, the adjustment of the operation power of the local electrolyzer based on the dynamic rating value of the current state factor comprises:

[0015] Based on the dynamic rating value of the current state factor, a compensation amount ΔP is determined i ; The specific formula is as follows:

[0016] ΔP i = G PI (t) [ω n - ω i + k fi (F ni - F hei )]

[0017] In the formula, ΔP i is a power adjustment value considering power sharing of multiple electrolyzers and system frequency recovery, ω n , ω i , F ni and F hei are the rated angular frequency, the actual rated angular frequency, the dynamic rating value of the current state factor, and the actual value of the current state factor of the local electrolyzer; the coefficient k fi is a proportional adjustment coefficient, and G PI (t) is a proportional integral adjustment unit.

[0018] An actual active power P ni is acquired.

[0019] determining a compensation amount ΔP based on the compensation amount ΔP i and the actual active power P ni , determining an active power reference value P i * ;

[0020] adjusting the operating power of the local electrolyzer based on the active power reference value P i * .

[0021] Optionally, the dynamic rating value based on the current state factor, determines a compensation amount ΔP i before the step includes:

[0022] based on the local delay timer completion status of the local electrolyzer and the communication status of the local electrolyzer, determining the dynamic rating value of the current state factor, wherein the communication status is used to indicate whether the local electrolyzer receives the dynamic rating value signal of the current state factor transmitted by the communication bus.

[0023] Optionally, the dynamic rating value based on the local delay timer completion status of the local electrolyzer and the communication status of the local electrolyzer, determining the dynamic rating value of the current state factor includes:

[0024] if the local delay timer of the local electrolyzer has received the dynamic rating value signal of the current state factor transmitted by the communication bus before completing the delay, at this time the dynamic rating value of the current state factor is equal to the actual value of the current state factor of the local electrolyzer;

[0025] if the local delay timer of the local electrolyzer has not received the dynamic rating value signal of the current state factor transmitted by the communication bus before completing the delay, at this time the actual value of the current state factor of the local electrolyzer is set as the dynamic rating value of the current state factor, and the communication bus right is occupied and locked, and the dynamic rating value signal of the current state factor is sent to the current network type electrolyzer and other electrolyzers of the system through the general bus.

[0026] if the local delay timer of the local electrolyzer has not received the dynamic rating value signal of the current state factor transmitted by the communication bus after completing the delay, indicating that the communication system has a fault, then the dynamic rating value of the current state factor is set to 1.

[0027] Optionally, the if not, adjusting the local electrolyzer to operate in a first constant power control mode includes:

[0028] if the actual value of the current state factor of the local electrolyzer is less than or equal to the lower limit value of the preset range of the safe operating current state factor of the local electrolyzer, then adjusting the local electrolyzer to operate in the first constant power control mode.

[0029] acquiring a first system frequency of the grid system; wherein the first system frequency is a current operating frequency of the grid system;

[0030] if the first system frequency is less than a first threshold value, stopping operating the local electrolyzer, wherein the first threshold value is a lower limit value of the current operating frequency of the grid system;

[0031] if the first system frequency is greater than the first threshold value, adjusting the local electrolyzer to operate in a first constant power control mode.

[0032] Optionally, the if not, adjusting the local electrolyzer to operate in a second constant power control mode, comprising:

[0033] if an actual value of a current state factor of the local electrolyzer is greater than or equal to an upper limit value of a preset range of a safe operating current state factor of the local electrolyzer, adjusting the local electrolyzer to operate in the second constant power control mode;

[0034] increasing a load on the grid system;

[0035] acquiring a second system frequency, wherein the second system frequency is an operating system frequency of the grid system after the load is increased;

[0036] if the second system frequency is less than a second threshold value, adjusting the local electrolyzer to operate in a second constant power control mode; wherein the second threshold value is an upper limit value of the operating frequency of the grid system before the load is increased.

[0037] Optionally, the increasing and the adjusting the local electrolyzer after the grid system step further comprises:

[0038] acquiring an overload operating time of the local electrolyzer;

[0039] if the overload operating time of the local electrolyzer is less than or equal to an upper limit value of the overload operating time, adjusting the local electrolyzer to operate in the second constant power control mode.

[0040] The present application has the following beneficial effects: the present application divides single-machine-group electrolyzers into three operating modes of maximum / minimum constant power control and grid control according to output characteristics and safety constraint conditions of the electrolyzers. The collaborative control strategy among multiple electrolyzers fully considers two operating modes and safety constraint conditions such as start-stop fluctuation of the electrolyzers, and performs power sharing and optimized rotation among the groups, thereby guaranteeing safe operation of the single-group electrolyzers.

[0041] In addition to the objects, features, and advantages described above, the present application has other objects, features, and advantages. The present application will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0042] The accompanying drawings, which form a part of the present application, are intended to provide further understanding of the present application and are incorporated herein for a purpose of explanations and are not intended as improper limitations on the present application. In the drawings:

[0043] Figure 1 is a structural diagram of a plurality of networked electrolytic cell systems according to an embodiment of the present application.

[0044] Figure 2 is a schematic diagram of an electrolytic cell safety area division according to the present application.

[0045] Figure 3 is a control block diagram of an electrolytic cell grid-connected interface converter according to a preferred embodiment of the present application.

[0046] Figure 4 is a flow chart of a local asynchronous delay algorithm of an electrolytic cell converter control system according to a preferred embodiment of the present application.

[0047] Figure 5 is a structural diagram of a local operating power adjustment method of a plurality of networked electrolytic cell systems according to an embodiment of the present application. DETAILED DESCRIPTION

[0048] The embodiments of the present application will be described in detail below with reference to the accompanying drawings, but the present application can be implemented in various different ways as limited and covered by the claims.

[0049] Hydrogen production equipment is crucial in the field of new energy. It can efficiently produce hydrogen, providing clean fuel for fuel cells and other devices, and promoting energy transformation and sustainable development. Electrolytic cells play a key role in hydrogen production equipment. They convert electrical energy into hydrogen energy by electrolyzing water, producing hydrogen efficiently and stably. They are the core components of green hydrogen production and energy transformation. The performance of electrolytic cells is therefore crucial. In summary, electrolytic cells, as a green electrical conversion device, are the key equipment for renewable energy water electrolysis hydrogen production technology. However, the electrolytic water hydrogen production system has poor dynamic regulation, low efficiency, and short lifespan under external grid voltage frequency fluctuation conditions, and even exceeds the safe operating domain. Especially when multiple electrolytic cells are connected in parallel to form an electrolytic cell array in a large-scale hydrogen production project, the power distribution between multiple electrolytic cells is unbalanced, which can cause individual electrolytic cells to exceed the safe operating domain, leading to repeated start-stop, affecting the service life of the electrolytic cell, and making it difficult to support the grid voltage frequency.

[0050] However, the existing hydrogen production system electrolytic cell control is divided into single and parallel multi-body levels. Single body with grid type control, ignoring the voltage amperometric characteristics, not to tap the network support capacity. Parallel multi-body with round value instruction optimization, not fully tap the characteristics of single body and complementary operating state, output processing extensive, simple working condition division, affecting the service life.

[0051] Therefore, in order to solve the above problems, a kind of multiple network type electrolytic cell parallel system local operation power adjustment method is proposed. Since the above method of the present application is based on multiple network type electrolytic cell parallel system, the specific structure of the multiple network type electrolytic cell parallel system 100 is described in detail in combination with Figure 1 , it is necessary to point out that, Figure 1 The number of electrolytic cell units in the above formula does not represent the actual application of electrolytic cell units, but is only used for easy understanding, and two groups of electrolytic cell units are exemplified for simple description.

[0052] The multiple network type electrolytic cell parallel system 100 mentioned in the present application comprises multiple parallel network type electrolytic cell units. As shown in Figure 1 , a network type electrolytic cell unit 110 comprises a hydrogen storage tank 111, an electrolytic cell 112 (electrolytic device), a DC / DC converter device 113 and a DC / AC converter device 114 connected in sequence. The multiple parallel electrolytic cell units generally comprise at least two electrolytic cell units, which are connected in parallel.

[0053] As shown in Figure 1 , multiple parallel network type electrolytic cell units are connected to the grid side through power lines, and each electrolytic cell unit is connected in parallel through a communication bus. This connection mode can realize the cooperative work of multiple electrolytic cell units. The grid side ensures stable power output, and the communication bus connection is convenient for centralized management and control.

[0054] Since the electrolytic cell current state factor is introduced in the present application, in order to facilitate understanding, the source and reasoning process of this concept need to be described:

[0055] Since the safe operation of electrolytic cell has the following conditions:

[0056] (1) hydrogen production efficiency constraint;

[0057]

[0058] Among them, η i is the hydrogen production efficiency, I he is the electrolytic cell current, α1, α2, α3 is the Faraday hydrogen production efficiency coefficient. exp represents the exponential function.

[0059] (2) the upper and lower limits of the safe operation power constraint;

[0060]

[0061] where, r1, r2 are electrolyte resistance coefficients; Tel is electrolytic tank temperature; Acell is electrolytic tank electrode area (Ri); Iel is electrolytic current; s1, s2, s3, t1, t2, t3 are electrode overvoltage coefficients; Urev is reversible voltage, F is Faraday constant, P i is actual power, V he is actual terminal voltage.

[0062] (3) overload time constraint;

[0063] (4) oscillation start and stop time interval constraint between different electrolytic tanks: in order to ensure the safety of the equipment, the start and stop of the electrolytic tank need a certain time interval, and cannot be frequently switched.

[0064] The intersection of the constraint conditions is obtained, and the lower limit and upper limit values of the safe running current of the electrolytic tank and three running intervals are obtained, as shown in the following formula (1) and formula (2). Figure 2 and formula (2).

[0065]

[0066] In the formula, T oldi is overload time, T max is maximum overload time, η i is hydrogen production efficiency, η min is minimum hydrogen production efficiency, η max is maximum hydrogen production efficiency, P i is actual power, P ni is rated power. T 启i is restart time, T 停i is upper cycle stop time, T tmax is maximum start-stop interval time.

[0067] As shown in the following formula (3), according to the safe running constraint condition, the current can be taken as the medium to be divided into three intervals, which is formula (4): Figure 2

[0068]

[0069] In the formula, I mini is the lower limit of the safe running current of the electrolytic tank, I maxi is the upper limit of the safe running current of the electrolytic tank.

[0070] As can be seen from the above relationship, the safe running constraint condition of the electrolytic tank is mostly related to the current, therefore, the concept of electrolytic tank current state factor F hei is proposed in the application, which is:

[0071] ​

[0072] In the formula, I hei is the actual operating current of the electrolyzer, I ni is the rated current of the electrolyzer. The safe region is divided by the state factor of the electrolyzer, which can be expressed as:

[0073]

[0074] In the formula, F min is the lower limit value of the state factor, F max is the upper limit value of the state factor. The state factor approximately normalizes the size of the electrolyzer current, with a unit of 1, which can realize the collaborative control of different parallel electrolyzers in the same physical coordinate system.

[0075] In order to avoid ambiguity in understanding the present application, the overall process of the invention is briefly described.

[0076] The electrolyzer interface converter control in the present application is mainly realized through the DC / DC converter control module 113 and the DC / AC converter control module 114 as shown in Figure 1 . Among them, the DC / DC converter control module 113 outputs a stable DC voltage and limits the electrolyzer current to run within the safe interval. The DC / AC converter control module 114 realizes network construction control and collaborative frequency support with other units. The detailed principles of each module are introduced in the following steps.

[0077] It should be noted that the electrolyzer mentioned here is any electrolyzer in the multiple network construction type electrolyzer parallel system.

[0078] The DC / DC converter control module includes a constant DC voltage control outer ring, an outer ring current limiting module, and an inner ring current control module. The DC voltage control module can stabilize the DC side voltage in multiple states and reduce system harmonics, as shown in formula (7). The outer ring current limiting module is constrained according to the maximum and minimum safe operating current of the electrolyzer, which can ensure that the minimum power of the electrolyzer is not lower than the minimum value and the overload power is not greater than the maximum value, fully guaranteeing the safe operation of the electrolyzer.

[0079]

[0080] In the formula, k vp is the DC voltage outer ring proportional parameter, k vi is the DC voltage outer ring integral parameter, dt is the integral term, V ni is the rated DC voltage, V dci is the actual DC voltage, is the inner ring current reference value. The subscript i represents the i-th group of electrolyzers.

[0081] When the current reference value generated by the outer loop is less than the lower limit of the safe operating current of the electrolytic cell, current limiting is required, and the inner loop current reference value is limited to the lower limit of the safe operating current of the electrolytic cell I . mini , the electrolytic cell operates in a constant power mode; interval 2: all the constraint conditions of the electrolytic cell can be met, and the power regulation ability is flexible, so that the interval can be operated in a grid forming control to help the system to regulate voltage and frequency. Interval 3: when the current reference value generated by the outer loop is greater than the upper limit of the safe operating current of the electrolytic cell, it is in an overload operating mode, in order to prevent further overload, the inner loop current reference value is limited to the upper limit of the safe operating current of the electrolytic cell I maxi , the electrolytic cell operates in an overload constant power mode.

[0082]

[0083] In the formula, I mini is the lower limit of the safe operating current of the electrolytic cell, I maxi is the upper limit of the safe operating current of the electrolytic cell, is the current reference value generated by the outer loop of the DC voltage, is the actual inner loop current reference value.

[0084] DC / AC converter control module: as shown in Figure 3 , the difference between the DC side voltage V dci and its reference value V ni is fed back to the active power control loop angular frequency reference value through the PI regulation unit, which is shown as formula (9), which helps to adjust the active power balance on the AC and DC sides.

[0085] ω dci =(k ωp +∫k ωi dt)(V ni -V dci ) (9)

[0086] In the formula, ω dci is the angular frequency adjustment amount for balancing the power on the AC and DC sides, k ωp is the angular frequency adjustment proportional parameter, and k ωi is the angular frequency adjustment integral parameter.

[0087] The active power reference value regulation module can adopt different power reference values according to the operating state of the electrolytic cell, as shown in formula (10), so that the system frequency can still be maintained near the rated value under different power states, and the power can be evenly distributed among different electrolytic cells according to the capacity proportion.

[0088] ​Because the current state is related to the operating state of the electrolyzer in real time and has rapid observability and measurability, the reference value P for adjusting the active power of the electrolyzer's DC / AC converter based on the current is used. i * Simultaneously transform S D Location:

[0089]

[0090] In the formula, P maxi P is the upper limit of the electrolytic cell's power operation. mini F is the lower limit of the electrolytic cell's power operation. hei F represents the actual value of the local electrolytic cell current state factor. min F is the lower limit of the state factor. max This is the upper limit of the state factor. That is, when the state factor of the electrolytic cell current exceeds the set range, S... D When the switch is in position 2, the DC / AC converter power reference value will be adjusted to the upper limit P. maxi Or the lower limit value P mini ,like Figure 3 As shown, its actual power value P i * With the rated value P i The difference is transmitted to the active power control loop (Current Loop) through the general-purpose PI2 unit, and enters the constant power mode to ensure the safety of the electrolyzer.

[0091] If within the flexible power range, that is, F min <F hei <F max S D When the switch is in position 1, network control is performed, and the compensation amount ΔP is increased. i ΔP i The power adjustment value considering the power sharing of multiple electrolyzer units and system frequency recovery is shown in equation (11). At this time, the active power reference value is P. i * =P ni +ΔP i .

[0092] ΔP i =G PI (t)[ω n -ω i +k fi (F ni -F hei (11)

[0093] In the formula, ω n ω i F ni and Fhei These are the rated angular frequency, the actual rated angular frequency, the dynamic rated value of the electrolytic cell current state factor in the current parallel unit, and the actual electrolytic cell current state factor; coefficient k fi G is a proportional adjustment coefficient that approximately reflects the relationship between the current and power of the electrolytic cell. PI (t) represents the proportional-integral control unit. When operating in network control mode, the active power reference value P... i * Subtract the actual active power P ni After k di The droop coefficient is obtained as Δω i .

[0094] At this time, the angular frequency of the system is ω i =ω n -Δω i +ω dci .

[0095] To achieve state awareness among multiple electrolytic cells and power coordination under multiple operating conditions. F ni This is set as the dynamic rated value of the electrolytic cell current state factor in the current parallel units. It is obtained based on the asynchronous delay algorithm (ADM) stage.

[0096] The basic principle of the ADM algorithm is shown in equation (12).

[0097] t hei =-k i (F hei -F ni )+T del (12)

[0098] In the formula, F ni The dynamic rated value of the current state factor for the current-state system of multiple grid-type electrolytic cells in parallel is obtained by transmission from the communication bus of the multiple grid-type electrolytic cells in parallel system. hei k represents the actual value of the current state factor of the local electrolyzer. i T is the proportionality coefficient. del For asynchronous delay period, t hei This is the local asynchronous delay time.

[0099] Actual value of local electrolytic cell current state factor F hei Subtract the dynamic rating of the current state factor F of the current system of multiple grid-type electrolytic cells in parallel. ni Multiply by the proportionality coefficient k i Subtract the asynchronous delay period T del Then the local asynchronous delay time t is obtained. hei Enter the timer to calculate the delay.

[0100] It should be noted that formula (12) is to calculate the local asynchronous delay time t hei .

[0101] The specific control process of ADM is shown in Figure 4 . The local electrolytic tank calculates the local asynchronous delay time into the timer calculation. If the current multiple network type electrolytic tank and the dynamic rating value of the system current state factor are received from the communication bus before the delay is completed, formula (11) is executed, and the timer is cleared and restarted to execute formula (12). If the local timer completes the delay before receiving the current multiple network type electrolytic tank and the dynamic rating value of the system current state factor signal from the communication bus, and no communication failure problem is detected, it means that the electrolytic tank is the current maximum power unit, and the actual value of the local electrolytic tank current state factor will become the new dynamic rating value of the multiple network type electrolytic tank and the system current state factor, occupy the communication bus right, and lock, send the dynamic rating value of the multiple network type electrolytic tank and the system current state factor to other electrolytic tanks. Other electrolytic tanks adjust the local power reference value according to the dynamic rating value of the multiple network type electrolytic tank and the system current state factor, such as formula (11), so that the current state factor of the local electrolytic tank approaches the dynamic rating reference value of the multiple network type electrolytic tank and the system current state factor. If there is a fault in the communication module of a certain electrolytic tank, the local signal participating in the coordinated control of multiple units is detected, and the dynamic rating value of the multiple network type electrolytic tank and the system current state factor in formula (11) is set to 1 to approach the rated power of the electrolytic tank. Run to avoid system instability caused by information error. Finally, the distributed coordinated power contribution of the network type electrolytic tank is realized, and the system frequency regulation is realized.

[0102] According to the above, the application provides a method for adjusting the local running power of a multiple network type electrolytic tank and system, which comprises, as Figure 5 indicated, the specific steps are as follows:

[0103] Step 501: Obtain the actual value of the current state factor of the local electrolytic tank; wherein the local electrolytic tank is any electrolytic tank in the multiple network type electrolytic tank and system, and the actual value of the current state factor is used to judge the safe operation range of the local electrolytic tank;

[0104] Because there are multiple electrolytic tank groups in the multiple network type electrolytic tank and system, and the power required to run each electrolytic tank group is different, the local electrolytic tank mentioned here is any electrolytic tank in the multiple network type electrolytic tank and system.

[0105] In the foregoing of the present application, the concept and inference of the current state factor have been elaborated in detail. As can be seen, the current state factor can be derived from the current approximation and can be used as a detection unit to intuitively reflect the working state of the electrolytic cell. That is, the actual value F hei of the current state factor of the local electrolytic cell here is used to determine the safe operating range of the local electrolytic cell. It is closely related to the current size in the electrolytic cell. Through monitoring and analysis of the current state factor, it can be understood whether the electrolytic cell is in normal operation, low-power operation or abnormal conditions such as possible overload. This helps the operator to timely grasp the running situation of the electrolytic cell, so as to take appropriate adjustment measures to ensure the stable operation of the electrolytic cell.

[0106] Step 502: judging and adjusting the operation mode of the local electrolytic cell based on the actual value of the current state factor of the local electrolytic cell;

[0107] Before using the electrolytic cell, a series of operating conditions need to be determined and set according to the specific application requirements, process requirements and characteristics of the equipment. These operating conditions include but are not limited to current intensity, voltage range, temperature, pressure, electrolyte composition and concentration, etc. That is, after the electrolytic cell is selected, the preset range of the safe operating current of the electrolytic cell is also determined, and the interval range of the current state factor for safe operation of the electrolytic cell is also determined. The above-mentioned preset range is a current range specially set for the safe operation of the local electrolytic cell, which highlights its purpose of ensuring the safety of the local electrolytic cell.

[0108] The specific process of judging and adjusting the operation mode of the local electrolytic cell is as follows:

[0109] Based on the actual value of the current factor of the local electrolytic cell, it is judged whether the actual value of the current state factor of the local electrolytic cell is within the preset range of the safe operating current state factor of the local electrolytic cell, and the operation mode of the local electrolytic cell is adjusted according to the judgment result;

[0110] If the actual value F hei of the current state factor of the local electrolytic cell is within the preset range of the safe operating current state factor of the local electrolytic cell, it means that all the constraint conditions of the electrolytic cell can be met, and it has flexible power adjustment capability, so this interval can be operated in network control to help system voltage and frequency regulation. At this time, the local electrolytic cell is adjusted to operate in network control mode, which fully guarantees the safe operation of the electrolytic cell, that is, the position of the SD switch in Figure 3 is switched to 1.

[0111] If the actual value F heiIf the current is not within the preset range of the safe operating current state factor of the local electrolyzer, serious consequences may occur, such as unstable operation of the electrolyzer and reduced hydrogen production efficiency. In this case, the local electrolyzer should be adjusted to operate in either the first or second constant power control mode, i.e., as follows: Figure 3 As shown, the SD switch is switched to position 2. Specifically: if the actual value of the current state factor of the local electrolytic cell is less than or equal to the lower limit of the safe operating range of the local electrolytic cell's power, the operating mode of the local electrolytic cell is adjusted to the first constant power control mode; if the actual value of the current state factor of the local electrolytic cell is greater than or equal to the upper limit of the safe operating range of the local electrolytic cell's power, the operating mode of the local electrolytic cell is adjusted to the second constant power control mode.

[0112] Step S503: If the local electrolytic cell is in network control mode, obtain the dynamic rated value of the current state factor transmitted on the communication bus of the current multiple network electrolytic cells in parallel system.

[0113] Since the operating power (active power reference value) of a local electrolyzer varies depending on its operating mode, the specific operating power is determined once the specific operating mode of the local electrolyzer is determined. The active power reference value adjustment module can use different power reference values ​​as shown in equation (10) according to the operating mode of the electrolyzer. This allows the system frequency to be maintained near the rated value under different operating modes, and enables the power of different electrolyzers to be evenly distributed and coordinated according to their capacity ratio. The rated value here is the frequency value that the current parallel system of multiple grid-type electrolyzers should maintain under ideal and standard operating conditions.

[0114]

[0115] According to formula (13), in the grid control mode, in order to ensure the normal operation of the local electrolytic cell, it is necessary to flexibly adjust its operating power. As can be seen from formula (14), the operating power needs to be determined by determining the dynamic rated value F of the current state factor transmitted by the communication bus of the current grid-type electrolytic cell parallel system. ni In this application, the electrolytic cell units in a parallel network electrolytic cell system share the dynamic rated value F of the current state factor transmitted on the communication bus. ni .

[0116] ΔP i =G PI (t)[ω n -ω i +k fi (F ni -F hei (14)

[0117] It should be noted that in actual situations, due to different electrolytic cells may be in different operating states, have different performance characteristics, or network system according to different needs for dynamic adjustment, therefore, the dynamic rating value F ni of the current state factor will change. That is, in this application at a certain moment in the working process of the electrolytic cell, there is a single dynamic rating value F ni of the current state factor on the communication bus.

[0118] It should be noted that in actual situations, due to different electrolytic cells may be in different operating states, have different performance characteristics, or network system according to different needs for dynamic adjustment, therefore, the dynamic rating value F ni of the current state factor will change. That is, in this application at a certain moment in the working process of the electrolytic cell, there is a single dynamic rating value F ni of the current state factor on the communication bus.

[0119] The dynamic rating value F ni of the current state factor in this application is mainly determined based on the local delay timer completion state of the local electrolytic cell and the communication state of the local electrolytic cell. The communication state is used to indicate whether the local electrolytic cell receives the dynamic rating value signal of the current state factor transmitted by the communication bus.

[0120] As shown in Figure 4 , the local asynchronous delay time t hei of the local electrolytic cell in the network control in this application is mainly obtained based on the ADM algorithm,

[0121] The basic principle of the ADM algorithm is shown in equation (15),

[0122] t hei = -k i (F hei -F ni )+T del (15)

[0123] In the formula, Fni is the dynamic rating value of the current state factor of the electrolytic cell in the parallel unit, which is obtained by the communication bus transmission. F hei is the actual value of the current state factor of the local electrolytic cell, k i is the proportional coefficient, T del is the asynchronous delay period, and t hei is the local asynchronous delay time.

[0124] The solving process of the dynamic rating value F ni of the current state factor is described in more detail:

[0125] If the local delay timer of the local electrolyzer has received the signal of the dynamic rating of the current state factor F ni from the communication bus before the delay time is completed, at this time the dynamic rating of the current state factor F ni equals the actual value of the current state factor F hei of the local electrolyzer, which means that the local electrolyzer has the maximum output, so it gets the signal of the dynamic rating first. Therefore, the dynamic rating of the current state factor F ni of the local electrolyzer equals the actual value of the current state factor F hei of the local electrolyzer. That is, the local electrolyzer in the application calculates the local asynchronous delay time into the timer, and before the delay time is completed, if the signal of the dynamic rating is received from the communication bus, formula (11) is executed, and the timer is cleared and formula (15) is executed again.

[0126] If the local delay timer of the local electrolyzer has not received the signal of the dynamic rating of the current state factor F ni from the communication bus before the delay time is completed, at this time the actual value of the current state factor F hei of the local electrolyzer is set to the dynamic rating of the current state factor F ni , and the communication bus right is occupied and blocked, and the signal of the dynamic rating of the current state factor F ni is sent to the current multiple networked electrolyzers and other electrolyzers in the system through the general bus; at this time, it means that the local electrolyzer has completed the delay time of the local timer before receiving the signal of the dynamic rating F ni from the communication bus, and no communication failure problem is detected, which means that the local electrolyzer is the current power maximum unit, and the actual value of the current state factor F hei of the local electrolyzer will become the new dynamic rating of the current state factor of the multiple networked electrolyzers and the system, and the communication bus right is occupied and blocked, and the signal is sent to other electrolyzers. Other electrolyzers adjust the local power reference value according to the reference value of the signal, as formula (14), so that the actual value of the current state factor F hei of the local electrolyzer approaches the dynamic rating reference value of the current state factor F ni .

[0127] If the local delay device of the local electrolyzer does not receive the signal of the dynamic rating value of the current state factor transmitted by the communication bus after completing the time delay, indicating that there is a communication failure, the dynamic rating value of the current state factor is set to 1. If there is a failure in the communication module of a certain electrolyzer, the local signal is detected to participate in the cooperative control of the multi-machine group, and the dynamic rating value in formula (14) is set to 1 to operate close to the rated power of the local electrolyzer, avoiding system instability caused by information error. Finally, the distributed cooperative power contribution of the network-constructed electrolyzer and the system frequency regulation are realized.

[0128] Step S504: Adjusting the operating power of the local electrolyzer based on the dynamic rating value of the current state factor.

[0129] In this application, in the network construction control mode, the dynamic rating value F ni of the current state factor transmitted by the communication bus is obtained, and then the operating power of the local electrolyzer is adjusted. ni After obtaining the dynamic rating value F i of the current state factor, the corresponding compensation amount is determined according to formula (14) mentioned above.

[0130] ΔP i = G PI (t) [ω n - ω i + k fi (F ni - F hei )] (16)

[0131] In the formula, ΔP i is the power adjustment value considering the power cooperative sharing of the multi-machine electrolyzer group and the system frequency recovery, ω n , ω i , F ni and F hei are the rated angular frequency, the actual rated angular frequency, the dynamic rating value of the current state factor, and the actual value of the current state factor of the local electrolyzer, respectively. Coefficient k fi is a proportional adjustment coefficient, and G PI (t) is a proportional integral adjustment unit. When operating in the network construction control mode, the active power reference value P ni is subtracted from the actual active power P ni , and then k di is passed through the droop coefficient to obtain Δω i . At this time, the angular frequency of the system is ω i = ω n - Δω i + ω dci .

[0132] After determining the compensation amount ΔP iSubsequently, according to formula (10), the reference value for active power is P. i * =P ni +ΔP i In other words, in order to determine the final operating power, i.e. the active power reference value P i * It is necessary to obtain the actual active power P. ni Finally, based on the compensation amount ΔP i and the actual active power P ni This allows us to determine the active power reference value P. i * Based on the active power reference value P i * Adjust the operating power of the local electrolytic cell. That is, after determining the active power reference value P... i * This power is then used as the operating power of the local electrolyzer at this time, so that the local electrolyzer operates at the active power reference value P. i * The operation of the electrolyzer alters its power consumption and helps regulate the system frequency.

[0133] In addition to the grid control mode, this application also includes a first or second constant power control mode. The specific control of the local electrolytic cell in this application under the first or second constant power control operation mode will be described in detail below:

[0134] First constant power control mode: If the actual value of the current state factor of the local electrolytic cell is less than or equal to the lower limit of the preset range of the safe operation current state factor of the local electrolytic cell, then the local electrolytic cell is adjusted to operate in the first constant power control mode.

[0135] After obtaining the actual value of the current state factor of the local electrolyzer, it is compared with the preset range of the safe operating current state factor of the local electrolyzer. If the actual value is less than or equal to the lower limit of the preset range, it means that the operating stability of the electrolyzer has decreased. The electrolyzer may experience unstable operation and large fluctuations, which may even lead to equipment failure.

[0136] Therefore, to avoid the aforementioned malfunctions, when the actual value of the local electrolytic cell's current state factor is less than or equal to the lower limit of the preset range for the safe operation of the local electrolytic cell's current state factor, the local electrolytic cell is first adjusted to operate in the first constant power control mode. In the first constant power mode, the reference value of the local electrolytic cell's active power is the lower limit of the electrolytic cell's power operation.

[0137] Then, by combining the system frequency of the network structure system, the next step of judgment is made: that is, to obtain the first system frequency of the network structure system; wherein, the first system frequency is the current operating frequency of the network structure system, and by combining the current operating frequency of the network structure system, a comprehensive judgment is made on the operation of the local electrolytic cell and whether it will affect the control of the entire network structure system.

[0138] If the frequency of the first system is less than the first threshold, the local electrolytic cell is stopped from operating, wherein the first threshold is the lower limit of the operating frequency of the current network system; if the frequency of the first system is greater than the first threshold, the local electrolytic cell is adjusted to operate at the first constant power.

[0139] In other words, if the operating frequency of the network system is less than the first threshold, it means that the operation of the local electrolytic cell may affect the performance of the network system. Therefore, the local electrolytic cell is stopped. If the frequency of the first system is greater than the first threshold, it means that under the current circumstances, the local electrolytic cell will not have a significant impact on the network system. The local electrolytic cell is then adjusted to operate at the first constant power.

[0140] Second constant power control mode: If the actual value of the current state factor of the local electrolyzer is greater than or equal to the upper limit of the preset range of the safe operation current state factor of the local electrolyzer, then the local electrolyzer is adjusted to operate in the second constant power control mode.

[0141] After obtaining the actual value of the current state factor of the local electrolyzer, it is compared with the preset range of the safe operating current state factor of the local electrolyzer. If it is greater than or equal to the upper limit of the preset range, excessive power will generate too much heat inside the electrolyzer, which may lead to overheating of components such as electrodes, electrolytes, and diaphragms. This will accelerate the aging and damage of components, and may even cause safety accidents such as fires. It may also cause electrical system overload, leading to electrical faults such as short circuits and open circuits, and damaging electrical equipment.

[0142] Therefore, to avoid the aforementioned malfunctions, when the actual value of the local electrolytic cell's current state factor is greater than or equal to the upper limit of the preset range for the safe operation of the local electrolytic cell's current state factor, the local electrolytic cell is first adjusted to operate in the second constant power control mode. In the second constant power mode, the reference value for the active power of the local electrolytic cell is the upper limit of the electrolytic cell's power operation.

[0143] Then, the load is increased, and the next step is to determine the operating frequency of the network system after the load is increased: that is, to increase the load on the network system.

[0144] Obtain the second system frequency, wherein the second system frequency is the system frequency at which the network system operates after the load is increased;

[0145] If the frequency of the second system is less than the second threshold, the local electrolytic cell is adjusted to operate at the second constant power; wherein, the second threshold is the upper limit of the operating frequency of the network system before the load is increased.

[0146] In other words, if the operating frequency of the grid system after the load increase is lower than the upper limit of the operating frequency of the grid system before the load increase, it means that there are almost no problems with the operation of the local electrolyzer, and the local electrolyzer can be adjusted to operate at the second constant power.

[0147] In addition, if the step of increasing the load on the network system includes:

[0148] Obtain the overload operating time of the local electrolytic cell;

[0149] If the overload operating time of the local electrolytic cell is less than or equal to the upper limit of the overload operating time, the local electrolytic cell is adjusted to operate at the second constant power.

[0150] During the operation of an electrolytic cell, the duration of overload operation will have different impacts. A short overload period may only cause minor damage to the equipment, such as overheating of some components. However, within the equipment's tolerance range, the equipment may return to normal operation after a period of cooling and adjustment. However, a prolonged overload period can lead to serious consequences. The equipment may damage critical components such as electrodes, electrolytes, or the control system due to overheating. This not only causes equipment failure but also increases maintenance costs and downtime, impacting production efficiency.

[0151] Therefore, in order to avoid overload failures, the overload operation time of a local electrolytic cell is usually limited to an upper limit.

[0152] In other words, after increasing the load on the grid system, the overload operating time of the local electrolyzer is collected. If the overload operating time of the local electrolyzer is less than or equal to the upper limit of the overload operating time, it means that the operation of the local electrolyzer is still within a safe and controllable range, and the local electrolyzer is adjusted to operate at the second constant power.

[0153] In summary, the interface converters of each electrolytic cell group in this application, combined with the output characteristics of the electrolytic cells and the safety operation constraints, control the single-group electrolytic cell array in a network mode to assist in supporting the grid-side voltage and frequency. When the upper and lower operating power limits are reached, the control switches to a constant power mode to ensure the safe operation of the single-group electrolytic cells. Furthermore, based on the concept of electrolytic cell state factors, a dynamic link relationship is established between multiple groups of electrolytic cells. When a power change occurs on the grid side, causing a change in system voltage and frequency, the unit with the maximum electrolytic cell state factor becomes the unified reference for the system. This reference value is sent to other units via a communication bus to adjust the power, achieving power balance among multiple electrolytic cell units and enhancing the support for system voltage and frequency. In particular, when any electrolytic cell unit reaches its upper or lower power limit, the unit is started or stopped by detecting whether the system voltage and frequency are within a reasonable range.

[0154] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for adjusting the local operating power of a parallel system of multiple grid-type electrolytic cells, characterized in that, include: Obtain the actual value of the current state factor of the local electrolytic cell; wherein, the local electrolytic cell is any electrolytic cell in the parallel system of multiple grid-type electrolytic cells, the actual value of the current state factor is used to determine the safe operating range of the local electrolytic cell, and the actual value of the current state factor is the ratio of the actual operating current of the electrolytic cell to the rated current of the electrolytic cell. Based on the actual value of the current state factor of the local electrolytic cell, determine whether the actual value of the current state factor of the local electrolytic cell is within the preset range of the safe operation current state factor of the local electrolytic cell, and adjust the operation mode of the local electrolytic cell according to the determination result. If so, adjust the operating mode of the local electrolyzer to network control mode; If not, adjust the local electrolyzer to operate in the first or second constant power control mode; If the local electrolyzer operates in a network control mode, obtain the dynamic rated value of the current state factor transmitted on the communication bus of the current multiple network electrolyzers in parallel system. Based on the dynamic rating of the current state factor, the compensation amount ΔP is determined. i The specific formula is as follows: ΔP i =G PI (t)[ω n -oh i +k fi (F ni -F hei )] In the formula, ΔP i To account for the power sharing and frequency recovery of multiple electrolytic cells, the power adjustment value ω n ω i F ni and F hei These are the rated angular frequency, the actual rated angular frequency, the dynamic rated value of the current state factor, and the actual value of the current state factor of the local electrolytic cell, respectively; coefficient k fi G is the proportional adjustment coefficient. PI (t) represents the proportional-integral control unit; Obtain the actual active power P ni ; Based on the compensation amount ΔP i and the actual active power P ni Determine the active power reference value P i * ; Based on the active power reference value P i * Adjust the operating power of the local electrolytic cell; The process for determining the dynamic rating of the current state factor is as follows: If the local delay unit of the local electrolytic cell has received the signal of the dynamic rating of the current state factor transmitted from the communication bus before the delay is completed, the dynamic rating of the current state factor is equal to the actual value of the current state factor of the local electrolytic cell. If the local delay unit of the local electrolytic cell does not receive the dynamic rated value signal of the current state factor transmitted from the communication bus before the delay is completed, the actual value of the current state factor of the local electrolytic cell is set to the dynamic rated value of the current state factor, the communication bus rights are occupied and locked, and the dynamic rated value signal of the current state factor is sent to other electrolytic cells in the parallel system of multiple network-type electrolytic cells via the general bus. If the local delay unit of the local electrolytic cell does not receive the dynamic rating signal of the current state factor transmitted from the communication bus after the delay is completed, it indicates that there is a fault in the communication system, and the dynamic rating of the current state factor is set to 1.

2. The method according to claim 1, wherein if not, adjusting the local electrolytic cell to operate in the first constant power control mode includes: If the actual value of the current state factor of the local electrolyzer is less than or equal to the lower limit of the preset range of the safe operation current state factor of the local electrolyzer, then the local electrolyzer is adjusted to operate in the first constant power control mode. Obtain the first system frequency of the network construction system; wherein, the first system frequency is the operating frequency of the current network construction system; If the frequency of the first system is less than the first threshold, the local electrolytic cell is stopped from operating, wherein the first threshold is the lower limit of the operating frequency of the current network system; If the frequency of the first system is greater than the first threshold, the local electrolytic cell is adjusted to operate at the first constant power.

3. The method according to claim 1, characterized in that, If not, then the local electrolytic cell is adjusted to operate in the second constant power control mode, including: If the actual value of the current state factor of the local electrolyzer is greater than or equal to the upper limit of the preset range of the safe operation current state factor of the local electrolyzer, then the local electrolyzer is adjusted to operate in the second constant power control mode. Increase the load on the network system; Obtain the second system frequency, wherein the second system frequency is the system frequency at which the network system operates after the load is increased; If the frequency of the second system is less than the second threshold, the local electrolytic cell is adjusted to operate at the second constant power; wherein, the second threshold is the upper limit of the operating frequency of the grid system before the load is increased.

4. The method according to claim 3, characterized in that, The step of increasing the load on the network system also includes: Obtain the overload operating time of the local electrolytic cell; If the overload operating time of the local electrolytic cell is less than or equal to the upper limit of the overload operating time, the local electrolytic cell is adjusted to operate at the second constant power.

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