Method for adjusting local operating power of parallel system of multiple net-forming type electrolytic cells

Abstract

The invention provides a method for adjusting the local operation power of a multi-network-forming-type electrolytic cell parallel system. The method comprises the steps that the actual value of a current state factor of a local electrolytic cell is obtained; wherein the local electrolytic cell is any electrolytic cell in the plurality of net-forming type electrolytic cell parallel systems, and the actual value of the current state factor is used for judging the safe operation working range of the local electrolytic cell; based on the actual value of the current state factor of the local electrolytic cell, judging and adjusting the operation mode of the local electrolytic cell; if the operation mode of the local electrolytic cell is a networking control mode, obtaining a dynamic rated value of a current state factor transmitted on a communication bus of a plurality of networking type electrolytic cell parallel systems at present; and adjusting the operating power of the local electrolytic cell based on the dynamic rated value of the current state factor. According to the scheme, when the network side power changes, the power among the multiple electrolytic cell units is balanced, and the supporting effect on the voltage frequency of the system is enhanced.

Description

Technical Field

[0001] The present application relates to the field of power coordination in networking, and in particular to the adjustment of the operating power of electrolytic cells in a networking structure. Background Art

[0002] The importance of hydrogen production in new power systems is increasing day by day. It has significant advantages in enhancing the consumption of new energy, energy storage, providing peak-shaving services, and promoting energy interconnection. (Characteristics of electrolyzers) Electrolyzers are the core equipment in the production of hydrogen production systems. Their interface converters and their control systems are the key links in realizing hydrogen production by water electrolysis. Compared with traditional energy conversion equipment, electrolyzers have many advantages, which support their application and development in the hydrogen energy industry.

[0003] The existing control of hydrogen production systems around electrolyzers is divided into two levels: single-body and parallel multi-body. The control around single-body electrolyzers is mainly carried out in a grid-following type, that is, the electrolyzer acts as a power-adjustable load to respond to the power fluctuations of renewable energy such as photovoltaic wind turbines. The characteristics of the two are combined to smooth the fluctuations of renewable energy in the grid-connected state or directly absorb it in the off-grid state. The voltage-ampere characteristics of the electrolyzer are ignored, and the grid-building support capacity of the electrolyzer is not fully explored. The method around parallel multi-body electrolyzers generally controls the rated power operation and shutdown of the electrolyzer through the optimization of rotation instructions, which alleviates the power imbalance phenomenon to a certain extent, but fails to fully explore the characteristics of each single body of the electrolyzer array and the real-time complementary operation status characteristics. The output processing of the electrolyzer is relatively extensive, the working condition division is simple, and the constraints such as the adjustment characteristics, start-stop times, and hydrogen production safety of the alkaline electrolyzer are not considered enough, which affects the life of the electrolyzer. Summary of the invention

[0004] The present application provides a system and method for adjusting the operating power of a local electrolytic cell based on a networking system, so as to solve the above-mentioned problems in the prior art.

[0005] To achieve the above-mentioned purpose, the present application also provides a method for adjusting the local operating power of a plurality of grid-type electrolyzer parallel systems, comprising:

[0006] 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 parallel system of the plurality of grid-type electrolytic cells, and the actual value of the current state factor is used to determine a safe operating range of the local electrolytic cell;

[0007] Based on the actual value of the current state factor of the local electrolytic cell, determining and adjusting the operation mode of the local electrolytic cell;

[0008] If the operation mode of the local electrolyzer is a network control mode, obtaining a dynamic rated value of a current state factor transmitted on a communication bus of a plurality of networked electrolyzer parallel systems;

[0009] Based on the dynamic rated value of the present current state factor, the operating power of the local electrolyzer is adjusted.

[0010] Optionally, 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 includes:

[0011] Based on the actual state value of the current factor of the local electrolytic cell, determine whether the actual value of the current state factor of the local electrolytic cell is within a 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;

[0012] If yes, adjusting the operation mode of the local electrolyzer to a network control mode;

[0013] If not, the local electrolyzer is adjusted to operate in the first or second constant power control mode.

[0014] Optionally, adjusting the operating power of the local electrolyzer based on the dynamic rated value of the current state factor comprises:

[0015] Based on the dynamic rated value of the current state factor, the 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] Where ΔP i To consider the power adjustment value of the electrolyzer power sharing of multiple units and system frequency recovery, ω n ,ω i , F ni and F hei are respectively 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 electrolyzer; the coefficient k fi is the proportional adjustment coefficient, G PI (t) is the proportional-integral regulation unit;

[0018] Get the actual active power P ni ;

[0019] Based on the compensation amount ΔP i and the actual active power P ni , determine the active power reference value

[0020] Based on the active power reference value The operating power of the local electrolyzer is adjusted.

[0021] Optionally, the compensation amount ΔP is determined based on the dynamic rated value of the current state factor. i Steps before include:

[0022] The dynamic rated value of the current state factor is determined based on the completion status of the local delayer of the local electrolyzer and the communication status of the local electrolyzer, wherein the communication status is used to indicate whether the local electrolyzer receives the dynamic rated value signal transmitted from the communication bus.

[0023] Optionally, determining the dynamic rated value of the current state factor based on the completion state of the local delay device of the local electrolyzer and the communication status of the local electrolyzer comprises:

[0024] If the local delayer of the local electrolytic cell has received the dynamic rated value signal of the current state factor transmitted by the communication bus before completing the delay, the dynamic rated value of the current state factor is equal to the actual value of the current state factor of the local electrolytic cell;

[0025] If the local delayer of the local electrolytic cell does not receive the dynamic rated value signal of the current state factor transmitted by 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, and 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 of the current multiple meshed electrolytic cell parallel system via the universal bus;

[0026] If the local delayer of the local electrolytic cell does not receive the dynamic rated value signal of the current state factor transmitted by the communication bus after completing the delay, indicating that there is a fault in the communication system, the dynamic rated value of the current state factor is set to 1.

[0027] Optionally, 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 electrolytic cell is less than or equal to the lower limit value of the preset range of the safe operation current state factor of the local electrolytic cell, the local electrolytic cell is adjusted to operate in the first constant power control mode;

[0029] Acquire a first system frequency of the networking system; wherein the first system frequency is an operating frequency of the current networking system;

[0030] If the first system frequency is less than a first threshold, the local electrolyzer is stopped, wherein the first threshold is the lower limit of the operating frequency of the current networking system;

[0031] If the first system frequency is greater than a first threshold, the local electrolyzer is adjusted to operate at the first constant power.

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

[0033] If the actual value of the current state factor of the local electrolytic cell is greater than or equal to the upper limit value of the preset range of the safe operation current state factor of the local electrolytic cell, the local electrolytic cell is adjusted to operate in the second constant power control mode;

[0034] Adding load to the network system;

[0035] Acquire a second system frequency, wherein the second system frequency is a system frequency of the network system after the load is increased;

[0036] If the second system frequency is less than a second threshold, the local electrolyzer 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.

[0037] Optionally, after the step of adding and building a networking system, the step further includes:

[0038] Obtaining the overload operation time of the local electrolytic cell;

[0039] If the overload operation time of the local electrolytic cell is less than or equal to the upper limit of the overload operation time, the local electrolytic cell is adjusted to operate at the second constant power.

[0040] The present application has the following beneficial effects: According to the output characteristics and safety constraints of the electrolyzer, the present application divides the single-unit electrolyzer into three operating modes: maximum / minimum constant power control and network control. The collaborative control strategy between multiple electrolyzers fully considers the two operating modes of the electrolyzer and safety constraints such as start-stop fluctuations, and performs power sharing and optimized rotation between the units, thereby ensuring the safe operation of a single group of electrolyzers.

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

[0042] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0043] Figure 1 It is a structural diagram of a parallel system of multiple grid-type electrolytic cells according to an embodiment of the present application.

[0044] Figure 2 It is a schematic diagram of the safe area division of the electrolytic cell of the present application.

[0045] Figure 3 This is a control block diagram of the electrolyzer grid-connected interface converter of the preferred embodiment of the present application.

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

[0047] Figure 5 It is a structural schematic diagram of a method for adjusting the local operating power of a system of multiple grid-type electrolytic cells in parallel provided in an embodiment of the present application. DETAILED DESCRIPTION

[0048] The embodiments of the present application are described in detail below with reference to the accompanying drawings; however, the present application can be implemented in many different ways as defined and covered by the claims.

[0049] Hydrogen production equipment is crucial in the field of new energy. It can efficiently produce hydrogen, provide clean fuel for fuel cells, etc., and promote energy transformation and sustainable development. The electrolyzer plays a key role in hydrogen production equipment. It converts electrical energy into hydrogen energy by electrolyzing water, and produces hydrogen efficiently and stably. It is the core component for achieving green hydrogen production and promoting energy transformation. The performance of the electrolyzer is therefore, for the electrolyzer (the dangers and demands of the electrolyzer) In summary, the electrolyzer, as a green electrical conversion device, is the key equipment for renewable energy electrolysis water hydrogen production technology. However, the electrolysis water hydrogen production system has poor dynamic adjustability, low efficiency, and life-span issues under the condition of external grid voltage frequency fluctuations, and even problems such as possible exceeding the safe operation domain. In particular, when multiple electrolyzers are connected in parallel to form an electrolyzer array in a large-scale hydrogen production project, the power distribution between multiple electrolyzers is unbalanced, which can easily cause individual electrolyzers to exceed the safe operation domain, causing repeated start and stop, affecting the service life of the electrolyzer, and it is difficult to play the advantages of supporting the grid voltage frequency.

[0050] However, the existing electrolyzer hydrogen production system is controlled at the single body level and parallel multi-body level. The single body is controlled by following the grid, ignoring the voltage volt-ampere characteristics and not exploring the network support capacity. The parallel multi-body is optimized by rotating instructions, not fully exploring the single body characteristics and complementary operating status, the output processing is rough, the working condition division is simple, and the service life is affected.

[0051] Therefore, in order to solve the above problems, the present application proposes a method for adjusting the local operating power of a plurality of grid-type electrolytic cells in parallel. Figure 1 , the specific structure of the multiple grid-type electrolyzer parallel system 100 is described in detail. It should be noted that, Figure 1 The number of electrolytic cell units does not represent the electrolytic cell units in actual applications. Just to facilitate understanding, two groups of electrolytic cell units are cited for simple explanation.

[0052] The multiple grid-type electrolytic cell parallel system 100 mentioned in this application includes multiple parallel grid-type electrolytic cell units. Figure 1 As shown, a grid-type electrolyzer unit 110 includes a hydrogen storage tank 111, an electrolyzer 112 (electrolyzer), a DC / DC converter 113, and a DC / AC converter 114, which are connected in sequence. The multiple parallel electrolyzer units here generally include at least two electrolyzer units, which are connected in parallel.

[0053] like Figure 1 As shown, multiple parallel grid-type electrolyzer units are connected to the grid side through power lines, and at the same time, each electrolyzer unit is connected in parallel through a communication bus. This connection method can realize the coordinated operation of multiple electrolyzer units. The grid side ensures stable power output, and the communication bus connection facilitates centralized management and control.

[0054] Since the concept of electrolytic cell current state factor is introduced in the application itself, it is necessary to explain the origin and reasoning process of this concept for easy understanding:

[0055] The safe operation of the electrolyzer has the following conditions:

[0056] (1) Hydrogen production efficiency constraints;

[0057]

[0058] Among them, η i is the hydrogen production efficiency, I he is the electrolyzer current, α1, α2, α3 are Faraday hydrogen production efficiency coefficients. exp represents an exponential function.

[0059] (2) Upper and lower power limits for safe operating power;

[0060]

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

[0062] (3) Overload time constraint;

[0063] (4) Constraints on the time intervals between the oscillating start and stop of different electrolytic cells: To ensure the safety of the equipment, there needs to be a certain time interval between the start and stop of the electrolytic cell, and frequent switching is not allowed.

[0064] The intersection of the constraints is used to obtain the lower and upper limits of the safe operating current of the electrolyzer and three operating intervals, such as Figure 2 And as shown in formula (2).

[0065]

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

[0067] like Figure 2 As shown, taking current as the detection unit, according to the safety operation constraints, it can be divided into three intervals with current as the medium, as shown in formula (4):

[0068]

[0069] In the formula, I mini is the lower limit of the safe operation current of the electrolytic cell, I maxi It is the upper limit of safe operation current of the electrolyzer;

[0070] From the above relationship, it can be seen that the safe operation constraints of the electrolytic cell are mostly related to the current. Therefore, this application proposes the electrolytic cell current state factor F hei The concept is:

[0071]

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

[0073]

[0074] In the formula, F min is the lower limit of the state factor, F max is the upper limit of the state factor. The state factor approximately normalizes the size of the electrolytic cell current, and its unit is 1, which can realize the coordinated control of different parallel electrolytic cells in the same physical coordinate system.

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

[0076] The electrolyzer interface converter control in this application is mainly through Figure 1 The DC / DC converter control module 110 and the DC / AC converter control module 120 shown in the figure are implemented. Among them, the DC / DC converter control module 110 outputs a stable DC voltage and limits the electrolyzer current to operate within a safe range. The DC / AC converter control module 120 implements network control and coordinated frequency support with other units. The detailed principle of each module is introduced step by step below.

[0077] It should be noted that the electrolytic cell mentioned here is any electrolytic cell in a parallel system of multiple grid-type electrolytic cells.

[0078] DC / DC converter control: It includes three parts: the fixed DC voltage control outer loop, the outer loop current limiting module, and the inner loop 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 loop current limiting module constrains the maximum and minimum safe operating currents of the electrolyzer, which can ensure that the minimum power of the electrolyzer is not less than the minimum value and the overload power is not greater than the maximum value, fully ensuring the safe operation of the electrolyzer.

[0079]

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

[0081] When the current reference value generated by the outer loop When the current is less than the lower limit of the safe operation current of the electrolyzer, current limiting is required. The reference value of the inner loop current I is the lower limit of the safe current of the electrolytic cell mini , the electrolyzer operates in constant power mode; Interval 2: All constraints of the electrolyzer can be met, and it has flexible power adjustment capabilities, so this interval can be operated as a network control to help the system adjust voltage and frequency. Interval 3: When the current reference value generated by the outer loop is greater than the upper limit of the safe operation current of the electrolyzer, it is in overload operation mode. To prevent further overload, the inner loop current reference value is limited to the upper limit of the safe operation current of the electrolyzer I maxi , the electrolyzer operates in overload constant power mode.

[0082]

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

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

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

[0086] In the formula, ω dci k is the angular frequency adjustment for balancing the power on both sides of AC and DC. ωp is the angular frequency adjustment scale parameter, k ωi Adjust the integration parameter for the angular frequency.

[0087] The active power reference value adjustment module can adopt different power reference values ​​according to the operating state of the electrolyzer 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 between different electrolyzers can be evenly distributed and coordinated according to the capacity ratio.

[0088] Since the current state is related to the operating state of the electrolyzer in real time and has rapid observability, the reference value of the active power of the electrolyzer DC / AC converter is adjusted according to the current. Simultaneously transform S D Location:

[0089]

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

[0091] If in the flexible power range, that is, F min <F hei <F max , S D The switch is in position 1, network control is performed, and the compensation amount ΔP is increased i . ΔP i The power adjustment value is considered to consider the coordinated sharing of power of multiple electrolyzers and system frequency recovery, as shown in formula (11). At this time, the active power reference value is

[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 F hei They are respectively 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; the coefficient k fi is the proportional adjustment coefficient, which approximately reflects the relationship between the electrolytic cell current and power. PI(t) is the proportional integral regulation unit. When operating in the grid control mode, the active power reference value 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] In order to achieve state perception between multiple groups of electrolyzers and power coordination under multiple operating states. ni Set to the dynamic rated value of the electrolytic cell current state factor in the current parallel group. Obtained according to the asynchronous delay algorithm link (ADM).

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

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

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

[0099] Actual value of the local electrolytic cell current state factor F hei Subtract the dynamic rated value F of the current state factor of the current multiple grid-type electrolyzer parallel system ni , multiplied by the proportionality factor k i , minus 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 used to calculate the local asynchronous delay time t hei .

[0101] ADM specific control process is as follows Figure 4As shown. The local electrolyzer calculates the local asynchronous delay time and enters the timer calculation. If the dynamic rated value of the current state factor of the current multiple meshed electrolyzer parallel system is received from the communication bus before the delay is completed, formula (11) is executed, the timer is cleared, and formula (12) is restarted. If the local timer completes the delay before receiving the dynamic rated value signal of the current state factor of the current multiple meshed electrolyzer parallel system transmitted from the communication bus, and detects that there is no communication failure, it means that the electrolyzer is the unit with the largest power at present, and the actual value of the current state factor of the local electrolyzer will become the dynamic rated value of the current state factor of the new multiple meshed electrolyzer parallel system, occupying the communication bus rights and interests, and locking, and sending the dynamic rated value of the current state factor of the multiple meshed electrolyzer parallel system to other electrolyzers. Other electrolyzers adjust the local power reference value according to the dynamic rated value of the current state factor of the parallel system of multiple meshed electrolyzers, as shown in formula (11), so that the current state factor of the local electrolyzer is close to the dynamic rated reference value of the current state factor of the parallel system of multiple meshed electrolyzers. If there is a fault in the communication module of an electrolyzer, the local signal is detected to participate in the coordinated control of multiple units, and the dynamic rated value of the current state factor of the parallel system of multiple meshed electrolyzers in formula (11) is set to 1, so as to operate close to the rated power of the electrolyzer and avoid system instability caused by information errors. Finally, the distributed coordinated power contribution of the meshed electrolyzer and the system frequency control are realized.

[0102] According to the above content, the present application provides a method for adjusting the local operating power of a plurality of grid-type electrolyzer parallel systems, including: Figure 5 The specific steps are as follows:

[0103] Step 501: 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 parallel-connected grid-type electrolytic cells, and the actual value of the current state factor is used to determine a safe operating range of the local electrolytic cell;

[0104] Since there are multiple electrolytic cell units in the parallel system of multiple grid-type electrolytic cells, and each electrolytic cell unit requires different operating power, the local electrolytic cell mentioned here is any electrolytic cell in the parallel system of multiple grid-type electrolytic cells.

[0105] In the above content of this application, the concept and inference of the current state factor have been elaborated in detail. It is not difficult to see that the current state factor can be approximated from the current and can be used as a detection unit to intuitively reflect the working state of the electrolytic cell. In other words, the actual value of the current state factor F of the local electrolytic cell here is hei, is used to determine the safe operating range of the local electrolytic cell. It is closely related to the current in the electrolytic cell. By monitoring and analyzing the current state factor, it is possible to understand whether the electrolytic cell is in normal operation, low-power operation, or may be in abnormal conditions such as overload. This helps operators to grasp the operating status of the electrolytic cell in a timely manner so as to take corresponding 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, it is necessary to determine and set a series of operating conditions based on the specific application needs, process requirements and equipment characteristics. These operating conditions include but are not limited to current intensity, voltage range, temperature, pressure, electrolyte composition and concentration, etc. In other words, 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 safe operating current state factor of the electrolytic cell is also determined. The above preset range is a current range specifically set for the safe operation of the local electrolytic cell, highlighting that its purpose is to ensure the safety of the local electrolytic cell.

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

[0109] Based on the actual state value of the current factor of the local electrolytic cell, determine whether the actual value of the current state factor of the local electrolytic cell is within a 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;

[0110] If the actual value of the current state factor F of the local electrolytic cell hei If the local electrolyzer is within the preset range of the safe operation current state factor, it means that all constraints of the electrolyzer can be met and it has flexible power adjustment capabilities. Therefore, this range can be operated in network control to help the system adjust voltage and frequency. At this time, adjust the local electrolyzer to operate in the network control mode to fully ensure the safe operation of the electrolyzer. Figure 2 Switch the SD switch position to 1.

[0111] If the actual value of the current state factor F of the local electrolytic cell heiIf the current state factor of the local electrolyzer is not within the preset range of the safe operation current state factor, serious consequences may occur, the electrolyzer may become unstable in operation, and the hydrogen production efficiency may be reduced. At this time, the local electrolyzer is adjusted to operate in the first or second constant power control mode, that is, as shown in 2, the position of the SD switch is switched to 2. Specifically: if the actual value state factor of the current state factor of the local electrolyzer is less than or equal to the lower limit of the local electrolyzer power safe operation range, the operation mode of the local electrolyzer is adjusted to the first constant power control mode; if the actual value state factor of the current state factor of the local electrolyzer is greater than or equal to the upper limit of the local electrolyzer power safe operation range, the operation mode of the local electrolyzer is adjusted to the second constant power control mode.

[0112] Step S503: if the operation mode of the local electrolyzer is the networking control mode, obtain the dynamic rated value of the current state factor transmitted on the communication bus of the current multiple networking electrolyzer parallel system;

[0113] Since the local electrolyzer operates in different modes, its corresponding operating power (active power reference value) is also different. Therefore, after determining the specific operating mode of the local electrolyzer, its corresponding specific operating power is also determined. The active power reference value adjustment module can use different power reference values ​​according to the electrolyzer operating mode as shown in formula (10), so that the system frequency can still be maintained near the rated value under different operating modes, and the power between different electrolyzers can be evenly shared and coordinated according to the capacity ratio. The rated value here is the frequency value that the current multiple grid-type electrolyzer parallel system should maintain under the ideal and standard operating state.

[0114]

[0115] According to formula (10), in order to ensure the normal operation of the local electrolyzer in the grid control mode, it is necessary to flexibly adjust its operating power. According to formula (11), the determination of the operating power requires the determination of the dynamic rated value F of the current state factor transmitted by the communication bus of the current multiple grid-type electrolyzer parallel system. ni In the present application, the electrolytic cell units in the multiple grid-type electrolytic cell parallel 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 )] (11)

[0117] It should be noted that in actual situations, since different electrolyzers may be in different operating states and have different performance characteristics, or the network system may be dynamically adjusted according to different needs, the dynamic rated value of the current state factor F ni That is, in this application, at a certain moment during the operation of the electrolyzer, there is a single dynamic rated value F of the current state factor on the communication bus. ni .

[0118] It should be noted that in actual situations, since different electrolyzers may be in different operating states and have different performance characteristics, or the network system may be dynamically adjusted according to different needs, the dynamic rated value of the current state factor F ni That is, in this application, at a certain moment during the operation of the electrolyzer, there is a single dynamic rated value F of the current state factor on the communication bus. ni .

[0119] The dynamic rating of the current state factor F in this application ni , which is mainly determined based on the completion state of the local delayer of the local electrolyzer and the communication state of the local electrolyzer. The communication state here is used to indicate whether the local electrolyzer receives the dynamic rated value signal of the current state factor transmitted by the communication bus.

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

[0121] The basic principle of the ADM algorithm is shown in formula (12):

[0122] t hei =-k i (F hei -F ni )+T del (12)

[0123] Where Fni is the dynamic rated value of the electrolytic cell current state factor in the current parallel unit, which is obtained by communication bus transmission. hei is the actual value of the local electrolytic cell current state factor, k i is the proportionality coefficient, T del is the asynchronous delay period, t hei It is the local asynchronous delay time.

[0124] To determine the dynamic rating of the current state factor F ni The solution process is explained in more detail:

[0125] If the local delay device of the local electrolyzer has received the dynamic rated value F of the current state factor transmitted by the communication bus before completing the delay, ni signal, at this time the dynamic rated value of the current state factor F ni Equal to the actual value of the local electrolytic cell current state factor F hei , which means that the local electrolyzer has the largest output, so the dynamic rated value signal is obtained first. Therefore, the dynamic rated value F of the current state factor in the local electrolyzer ni Equal to the actual value of the current state factor F of the local electrolytic cell hei That is, the local electrolytic cell in the present application calculates the local asynchronous delay time and enters the timer calculation. Before the delay is completed, if a dynamic rated value signal transmitted from the communication bus is received, formula (11) is executed, the timer is reset, and formula (12) is restarted.

[0126] If the local delay device of the local electrolyzer does not receive the dynamic rated value F of the current state factor transmitted by the communication bus before the delay is completed, ni The actual value of the local electrolytic cell current state factor F hei Set to the dynamic rating of the current state factor F ni , while occupying the communication bus rights and blocking, the dynamic rated value of the current state factor F ni The signal is sent to other electrolyzers in the current multiple meshed electrolyzer parallel system via the universal bus; this means that if the local electrolyzer receives the dynamic rated value F transmitted by the communication bus ni Before the signal is received, the local timer completes the delay and detects no communication failure, indicating that the local electrolyzer is the unit with the largest power at present. The actual value of the current state factor of the local electrolyzer is F hei The dynamic rated value of the new current state factor of the parallel system of multiple grid-type electrolyzers will be occupied by the communication bus rights and locked, and the signal will be sent to other electrolyzers. Other electrolyzers adjust the local power reference value according to the signal reference value, as shown in formula (11), so that the actual value of the current state factor of the local electrolyzer F hei Dynamic rated reference value F close to the current state factor ni .

[0127] If the local delayer of the local electrolyzer does not receive the signal of the dynamic rated value of the current state factor transmitted by the communication bus after the delay is completed, indicating that there is a communication failure, the dynamic rated value of the current state factor is set to 1. If there is a failure in a communication module of an electrolyzer, the local signal is detected to participate in the coordinated control of multiple units, and the dynamic rated value in formula (11) is set to 1 to operate close to the rated power of the local electrolyzer to avoid system instability caused by information errors. Finally, the distributed coordinated power contribution of the grid-type electrolyzer and the system frequency control are realized.

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

[0129] In this application, in the network control mode, the dynamic rated value F of the current state factor transmitted on the communication bus is mainly obtained. ni After that, the operating power of the local electrolyzer is adjusted, and the dynamic rated value of the current state factor F is obtained. ni Then, the corresponding compensation amount is determined according to the formula (11) mentioned above.

[0130] ΔP i =G PI (t)[ω n -ω i +k fi (F ni -F hei )] (11)

[0131] Where ΔP i To consider the power adjustment value of the electrolyzer power sharing of multiple units and system frequency recovery, ω n ,ω i , F ni and F hei are respectively 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 electrolyzer; the coefficient k fi is the proportional adjustment coefficient, G PI (t) is the proportional integral regulation unit; when operating in the network control mode, the active power reference value P ni Subtract the actual active power P ni , after k di The droop coefficient is obtained as 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 value ΔP iLater, according to formula (10), the active power reference value is That is to say, in order to determine the final operating power, that is, the active power reference value It is necessary to obtain the actual active power P ni , and finally based on the compensation amount ΔP i and the actual active power P ni , so that the active power reference value can be determined Based on the active power reference value Adjust the operating power of the local electrolyzer. That is, after determining the active power reference value Then use it as the operating power of the local electrolyzer at this time, so that the local electrolyzer uses the active power reference value operation, thereby changing the electrolyzer power consumption and helping to regulate the system frequency.

[0133] In addition to the network control mode, the present application also includes the first or second constant power control mode. Here, the specific control of the local electrolyzer in the present application under the first constant power or second constant power control operation mode is described in detail:

[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 value of the preset range of the safe operation current state factor of the local electrolytic cell, 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 electrolytic cell, it is compared with the preset range of the safe operation current state factor of the local electrolytic cell. If it 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, it means that the operation stability of the electrolytic cell has decreased. The electrolytic cell may be unstable and fluctuate greatly, and may even cause equipment failure.

[0136] Therefore, in order to avoid the above fault situation, when 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 operation current state factor of the local electrolyzer, the local electrolyzer is first adjusted to operate in the first constant power control mode. The first constant power mode is that the reference value of the active power of the local electrolyzer is the lower limit of the electrolyzer power operation.

[0137] Then, combined with the system frequency of the networking system, the next step of judgment is carried out: that is, the first system frequency of the networking system is obtained again; wherein, the first system frequency is the operating frequency of the current networking system, and combined with the operating frequency of the current networking system, a comprehensive judgment is made on the operation status of the local electrolytic cell to determine whether it will affect the control of the entire networking system.

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

[0139] That is to say, if the operating frequency of the networking system is less than the first threshold at this time, it means that the operation of the local electrolyzer may affect the performance of the networking system, so the local electrolyzer is stopped. If the first system frequency is greater than the first threshold, it means that under the current situation, the local electrolyzer will not have too much impact on the networking system, and the local electrolyzer is 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 electrolytic cell is greater than or equal to the upper limit value of the preset range of the safe operation current state factor of the local electrolytic cell, the local electrolytic cell 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 operation current state factor of the local electrolyzer. If it is greater than or equal to the upper limit of the preset range of the safe operation current state factor of the local electrolyzer, excessive power will generate too much heat inside the electrolyzer, which may cause 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 overloads, cause electrical faults such as short circuits and open circuits, and damage electrical equipment.

[0142] Therefore, in order to avoid the above fault situation, when the actual value of the current state factor of the local electrolyzer is greater than or equal to the upper limit value of the preset range of the safe operation current state factor of the local electrolyzer, the local electrolyzer is first adjusted to operate in the second constant power control mode. The second constant power mode is that the reference value of the active power of the local electrolyzer is the upper limit of the electrolyzer power operation.

[0143] Then, the load is increased, and the next step of judgment is made according to the operating frequency of the network system after the load is increased: that is, the load is increased to the network system;

[0144] Acquire a second system frequency, wherein the second system frequency is a system frequency of the network system after the load is increased;

[0145] If the second system frequency is less than a second threshold, the local electrolyzer 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.

[0146] That is to say, if the operating frequency of the network system after the load is increased is less than the upper limit of the operating frequency of the network system before the load is increased, it means that there is almost no problem in the operation of the local electrolyzer, and the local electrolyzer can be adjusted to operate at the second constant power.

[0147] In addition, if after the step of increasing the load on the networking system, the following steps are further included:

[0148] Obtaining the overload operation time of the local electrolytic cell;

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

[0150] During the operation of the electrolyzer, if overload operation occurs, the length of the overload operation time will have different effects. If the overload operation time is short, it may only cause minor damage to the equipment, such as causing some components to heat up, but within the tolerance range of the equipment, after a period of cooling and adjustment, the equipment may resume normal operation. However, if the overload operation time is long, it will bring many serious consequences. The equipment may damage key components such as electrodes, electrolytes or control systems due to overheating. This will not only cause equipment failure, but also increase maintenance costs and downtime, affecting production efficiency.

[0151] Therefore, in order to avoid overload fault conditions, the overload operation time of the local electrolyzer usually has an upper limit.

[0152] That is to say, after adding load to the network system, the overload operation time of the local electrolyzer is collected. If the overload operation time of the local electrolyzer is less than or equal to the upper limit of the overload operation 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 converter of each group of electrolytic cells in the present application, combined with the output characteristics of the electrolytic cell and the safe operation constraints, controls the single group of electrolytic cell arrays into a network mode to assist in supporting the voltage and frequency on the grid side. When the upper and lower power limits of the operation are reached, the control is in a constant power mode to ensure the safe operation of a single group of electrolytic cells. And based on the concept of electrolytic cell state factor, a dynamic link relationship between multiple groups of electrolytic cells is established. When power changes occur on the grid side, resulting in changes in the system voltage and frequency, the unit with the maximum electrolytic cell state factor becomes the unified reference of the system, and this reference value is sent to other units through the communication bus to adjust the power, so as to achieve power balance between multiple electrolytic cell units and enhance the support for the system voltage and frequency. In particular, when any electrolytic cell unit reaches the upper or lower power limit, the electrolytic cell unit is started and stopped by detecting whether the system voltage and frequency are within a reasonable range.

[0154] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for adjusting the local operating power of a plurality of grid-type electrolyzer parallel systems, characterized in that: include: 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 parallel system of the plurality of grid-type electrolytic cells, and the actual value of the current state factor is used to determine a safe operating range of the local electrolytic cell; Based on the actual value of the current state factor of the local electrolytic cell, determining and adjusting the operation mode of the local electrolytic cell; If the operation mode of the local electrolyzer is a network control mode, obtaining a dynamic rated value of a current state factor transmitted on a communication bus of a parallel system of multiple networked electrolyzers; Based on the dynamic rated value of the current state factor, the operating power of the local electrolyzer is adjusted.

2. The adjustment method according to claim 1, characterized in that: The step of 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 comprises: Based on the actual state value of the current factor of the local electrolytic cell, determine whether the actual value of the current state factor of the local electrolytic cell is within a 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 yes, adjusting the operation mode of the local electrolyzer to a network control mode; If not, the local electrolyzer is adjusted to operate in the first or second constant power control mode.

3. The method according to claim 1, characterized in that The step of adjusting the operating power of the local electrolyzer based on the dynamic rated value of the current state factor comprises: Based on the dynamic rated value 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 consider the power adjustment value of the electrolyzer power sharing of multiple units and system frequency recovery, ω n ,ω i , F ni and F hei are respectively 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 electrolyzer; the coefficient k fi is the proportional adjustment coefficient, G PI (t) is the proportional integral regulation 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 electrolyzer.

4. The method according to claim 3, characterized in that The compensation amount ΔP is determined based on the dynamic rated value of the current state factor. i The steps before include: Based on the completion status of the local delay timer of the local electrolyzer and the communication status of the local electrolyzer, the dynamic rated value of the current state factor is determined, wherein the communication status is used to indicate whether the local electrolyzer has received a signal of the dynamic rated value of the current state factor transmitted from a communication bus of a parallel system of multiple meshed electrolyzers.

5. The method according to claim 4, characterized in that The step of determining the dynamic rated value of the current state factor based on the completion state of the local delay device of the local electrolyzer and the communication status of the local electrolyzer comprises: If the local delayer of the local electrolytic cell has received the signal of the dynamic rated value of the current state factor transmitted by the communication bus before completing the delay, then the dynamic rated value of the current state factor is equal to the actual value of the current state factor of the local electrolytic cell; If the local delayer 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, and 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 of the multiple meshed electrolytic cell parallel system via the universal bus; If the local delayer of the local electrolytic cell does not receive the dynamic rated value signal of the current state factor transmitted by the communication bus after completing the delay, indicating that there is a fault in the communication system, the dynamic rated value of the current state factor is set to 1.

6. The method according to claim 2, wherein if no, adjusting the local electrolyzer to operate in a first constant power control mode comprises: If the actual value of the current state factor of the local electrolytic cell is less than or equal to the lower limit value of the preset range of the safe operation current state factor of the local electrolytic cell, the local electrolytic cell is adjusted to operate in the first constant power control mode; Acquire a first system frequency of the networking system; wherein the first system frequency is an operating frequency of the current networking system; If the first system frequency is less than a first threshold, the local electrolyzer is stopped, wherein the first threshold is the lower limit of the operating frequency of the current networking system; If the first system frequency is greater than a first threshold, the local electrolyzer is adjusted to operate at the first constant power.

7. The method according to claim 2, characterized in that If not, adjusting the local electrolyzer to operate in a second constant power control mode includes: If the actual value of the current state factor of the local electrolytic cell is greater than or equal to the upper limit value of the preset range of the safe operation current state factor of the local electrolytic cell, the local electrolytic cell is adjusted to operate in the second constant power control mode; Adding load to the network system; Acquire a second system frequency, wherein the second system frequency is a system frequency of the network system after the load is increased; If the second system frequency is less than a second threshold, the local electrolyzer 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.

8. According to claim 7, after the step of adding the networking system, the step further comprises: Obtaining the overload operation time of the local electrolytic cell; If the overload operation time of the local electrolytic cell is less than or equal to the upper limit of the overload operation time, the local electrolytic cell is adjusted to operate at the second constant power.

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