Electrolytic cell cluster control method based on photovoltaic output, medium and equipment

Abstract

The invention discloses an electrolytic cell cluster control method based on photovoltaic output, a medium and equipment, and the method comprises the steps: based on photovoltaic prediction data, considering a photovoltaic prediction error and the influence of sudden rising or sudden falling of photovoltaic in a short period; in order to ensure that photovoltaic output predicted in the future at any moment can balance source load by adjusting the rise and fall of the started electrolytic cell load, the running number Nope (t) of the electrolytic cell cluster is obtained, the running number of the electrolytic cell cluster is corrected, concave points or convex points on a planned electrolytic cell cluster running number curve are eliminated, and the running number of the electrolytic cell cluster is calculated. The method is suitable for the day-ahead start-stop planning of the electrolytic cell cluster with photovoltaic fluctuation and intermittent output characteristics, realizes the planning of the running number of the electrolytic cells in the angelica keiskei day, provides a basis and support for the next intra-day start and scheduling of the electrolytic cells, and has good practicability.

Description

Technical Field

[0001] The present invention belongs to the technical field of industrial hydrogen production, and specifically relates to a photovoltaic-based electrolyzer cluster control method, medium and equipment. Background Art

[0002] At present, hydrogen energy is considered to be the most promising energy carrier in the future because of its clean, pollution-free, efficient and renewable characteristics. New energy electrolysis hydrogen production can promote the large-scale development of new energy. On the one hand, hydrogen production adds a new way for the nearby consumption of wind and solar power, and green hydrogen can also reduce carbon emissions in the chemical, transportation and other industries; on the other hand, the hydrogen production system can be used as a flexible load to participate in the field of power peak regulation through the synergy of electricity and hydrogen, so new energy hydrogen production is receiving more and more attention. In renewable energy hydrogen production projects, due to the capacity of a single electrolyzer, large-scale hydrogen production systems must be operated by a combination of multiple electrolyzers to form an electrolyzer cluster. However, the cold start time of the alkaline electrolyzers commonly used in existing projects is relatively long, and the photovoltaic output is in real-time change. Therefore, it is necessary to plan the number of electrolyzer cluster operations and the start and stop time on the day-ahead time scale so that the start-up of the electrolyzer to be operated can be completed in advance during the intraday scheduling stage. Summary of the invention

[0003] The purpose of the present invention is to provide a method, medium and device for controlling an electrolyzer cluster based on photovoltaic output, aiming to solve the above-mentioned problems.

[0004] The present invention is mainly achieved through the following technical solutions:

[0005] A control method for electrolyzer clusters based on photovoltaic output is based on photovoltaic prediction data, and takes into account the photovoltaic prediction error and the impact of sudden increase or decrease in photovoltaic power in the short term, so as to ensure that the photovoltaic output at any time in the future prediction can be adjusted by adjusting the load of the started electrolyzer to achieve source-load balance as the goal, and obtain the number of electrolyzer cluster operations N ope (t):

[0006] (1) According to formula (7), the number of electrolytic cell clusters in operation at time t is calculated as:

[0007] N ope (t) = ceil[(N lower (t)+N upper (t)) / 2] (7)

[0008] Where: N lower (t) represents the lower limit of the number of electrolyzer clusters in operation;

[0009] N upper (t) represents the upper limit of the number of electrolyzer clusters in operation;

[0010] ceil(.) represents the rounding operation, which rounds toward positive infinity;

[0011] t represents the time scale of PV prediction;

[0012] (2) According to formula (8), the number of electrolytic cell clusters in operation is processed in segments:

[0013]

[0014] Where: N represents the total number of electrolytic cells;

[0015] (3) For the concave or convex points of the electrolytic cell cluster operation quantity curve, the electrolytic cell cluster operation quantity is corrected according to formula (9):

[0016]

[0017] Where: k represents the time interval of considering the correction of concave or convex points.

[0018] In order to better implement the present invention, further, k is equal to 2.

[0019] In order to better implement the present invention, further, for the scenario where the photovoltaic output fluctuates violently, formula (9) is processed multiple times until the set requirements are met.

[0020] In order to better implement the present invention, the following steps are further included:

[0021] Step S1: Based on the obtained photovoltaic prediction data, the photovoltaic prediction output upper limit and output lower limit are calculated using formula (2);

[0022]

[0023] Where: P en (t) represents the predicted photovoltaic output;

[0024] P lower (t) indicates the lower limit of output;

[0025] P upper (t) indicates the upper limit of output;

[0026] t represents the time scale of PV prediction;

[0027] δ represents the accuracy of PV prediction data;

[0028] Step S2: Calculate the upper limit and lower limit of the number of electrolytic cell cluster operations according to formula (3) and formula (4) respectively;

[0029] N lower (t) = fix[(P lower (t)-Poth ) / (a*P rat )] (3)

[0030] N upper (t) = ceil[(P upper (t)-P oth ) / (b*P rat )] (4)

[0031] Where: N lower (t) represents the lower limit of the number of electrolyzer clusters in operation;

[0032] P oth Indicates the power consumption of public and auxiliary power in the hydrogen production plant;

[0033] a represents the minimum power factor for safe operation;

[0034] b represents the maximum power factor for safe operation;

[0035] P rat Indicates the rated power of the electrolyzer;

[0036] fix(.) indicates rounding operation, rounding towards zero;

[0037] N upper (t) represents the upper limit of the number of electrolyzer clusters in operation;

[0038] ceil(.) represents the rounding operation, which rounds toward positive infinity;

[0039] Step S3: segmenting the upper limit and lower limit of the number of electrolytic cell cluster operations according to formula (5) and formula (6);

[0040]

[0041] Step S4: Calculate the number of electrolytic cell clusters in operation according to formula (7);

[0042] Step S5: segment the number of electrolytic cell cluster operations according to formula (8);

[0043] Step S6: Correct the number of electrolytic cell cluster operations according to formula (9);

[0044] Step S7: Output the number and time of electrolytic cell cluster operation.

[0045] In order to better implement the present invention, further, in step S1, the safe operating range of a single electrolytic cell is:

[0046] a*P rat ≤P el ≤b*P rat(1)

[0047] Where: P el Indicates the operating power of a single electrolyzer;

[0048] Based on formula (1) and formula (2), formula (3) and formula (4) are obtained.

[0049] In order to better implement the present invention, further, in step S2, the lower limit and upper limit of the number of electrolytic cell cluster operations are calculated respectively by formula (3) and formula (4). If the data calculated by formula (3) and / or formula (4) is less than or equal to 0, it is considered that the data does not meet the actual needs, and the process goes to step S3, and the data is processed according to formula (5) and formula (6). The processed data is calculated in turn by steps S4 and S5 to obtain the number of electrolytic cell cluster operations; then, for the electrolytic cell cluster operation number curve with concave or convex points, the concave or convex points are corrected by formula (9) in step S6.

[0050] A computer-readable storage medium stores a computer program, which implements the above method when executed by a processor.

[0051] An electronic device comprises a memory and a processor; the memory stores a computer program; the processor is used to execute the computer program in the memory to implement the above method.

[0052] The beneficial effects of the present invention are as follows:

[0053] The present invention can obtain the number of electrolytic cell cluster operations at time t based on the solved upper and lower limits of the number of electrolytic cell cluster operations; and correct the concave points or convex points on the planned electrolytic cell cluster operation number curve to eliminate the concave points or convex points, adapt to the day-ahead start and stop planning of the electrolytic cell cluster with photovoltaic fluctuations and intermittent output characteristics, realize the planning of the number of electrolytic cell operations for tomorrow, provide a basis and support for the next step of electrolytic cell daily start and scheduling, and have good practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a flow chart of the electrolyzer cluster control method based on photovoltaic output of the present invention;

[0055] Figure 2 The photovoltaic power output curve diagram of the previous day in Example 2;

[0056] Figure 3 The upper and lower limit curves of photovoltaic output in Example 2;

[0057] Figure 4 It is a curve chart of the number of electrolytic cell cluster operations in Example 2;

[0058] Figure 5 is a graph showing the number of electrolytic cell cluster operations after correction in Example 2;

[0059] Figure 6 This is the adjustable range curve of the electrolytic cell in Example 2. DETAILED DESCRIPTION

[0060] Embodiment 1:

[0061] A control method for electrolyzer clusters based on photovoltaic output is suitable for the day-ahead start-stop planning of electrolyzer clusters with photovoltaic fluctuations and intermittent output characteristics. It aims to realize the planning of the start-stop of electrolyzer clusters: through photovoltaic prediction data, the number of electrolyzer operations and the start-stop time are planned under photovoltaic prediction errors. In addition, the impact of sudden increases or decreases in photovoltaic power in the short term on the planning needs to be considered. The main goal is to ensure that the photovoltaic output at any time in the future forecast can be balanced by adjusting the load of the started electrolyzers. The focus is on the planning of the adjustable capacity of the electrolyzer cluster. Figure 1 As shown, the specific steps include:

[0062] In a photovoltaic hydrogen production system, when the operating power of a single electrolyzer is too low, there may be a safety risk of excessive hydrogen in oxygen. Therefore, the electrolyzer generally needs to set a minimum safe operating power, and the minimum power coefficient for safe operation is recorded as a. In addition, a single electrolyzer also has a maximum safe operating power, and the maximum power coefficient for safe operation is recorded as b. The safe operating range of a single electrolyzer is:

[0063] a*P rat ≤P el ≤b*P rat (1)

[0064] Where P el Represents the operating power of a single electrolytic cell; P rat Indicates the rated power of the electrolyzer.

[0065] The photovoltaic prediction data is obtained through the photovoltaic prediction system, which has certain errors. The accuracy of the photovoltaic prediction data is δ, and the upper and lower limits of photovoltaic output taking into account the photovoltaic prediction error are:

[0066]

[0067] Where P en (t) represents the predicted photovoltaic output; P lower (t) represents the lower limit of the output taking into account the photovoltaic prediction error; P upper (t) represents the upper limit of output taking into account the photovoltaic prediction error; t represents the time scale of photovoltaic prediction, which is generally 15 minutes.

[0068] In hydrogen production projects, in order to reduce the cost of hydrogen production, it is generally necessary to reduce the use of grid electricity and use photovoltaic power generation as much as possible. To this end, it is generally required that the public auxiliary equipment of the electrolyzer, such as gas-liquid separation and compressor, also use photovoltaic power supply.

[0069] Based on the lower limit of the operation of a single electrolyzer and the lower limit of the predicted photovoltaic output, the lower limit of the number of electrolyzer clusters can be calculated as:

[0070] N lower (t) = fix[(P lower (t)-P oth ) / (a*P rat )] (3)

[0071] Where N lower (t) represents the lower limit of the number of electrolyzer clusters in operation; P oth represents the power consumption of the public utilities in the hydrogen production plant; fix(.) represents the rounding operation, which is rounded towards zero to ensure that the lower limit power of the electrolyzer cluster is below the lower limit of the photovoltaic predicted output.

[0072] Based on the upper limit of the operation of a single electrolyzer and the upper limit of the predicted photovoltaic output, the upper limit of the number of electrolyzer clusters can be calculated as:

[0073] N upper (t) = ceil[(P upper (t)-P oth ) / (b*P rat )] (4)

[0074] Where N upper (t) represents the upper limit of the number of electrolyzer clusters in operation; ceil(.) represents the rounding operation, which rounds toward positive infinity to ensure that the upper limit power of the electrolyzer cluster is above the upper limit of the predicted photovoltaic output.

[0075] The output of photovoltaic power starts from zero. Therefore, when the output of photovoltaic power is lower than the auxiliary power, N lower (t) and N upper (t) is a negative number, which obviously does not meet the actual needs and needs to be processed:

[0076]

[0077] Based on the upper and lower limits of the number of electrolytic cell clusters running, the number of electrolytic cell clusters running at time t, N, can be obtained. ope (t) is:

[0078] N ope (t) = ceil[(N lower (t)+N upper (t)) / 2] (7)

[0079] In order to avoid the number of electrolyzer clusters to be solved exceeding the total number of electrolyzers N in the hydrogen production plant, for N ope (t) Segment processing:

[0080]

[0081] The random and volatile output characteristics of photovoltaic power generation lead to large fluctuations in output data, which is reflected in the curve of the planned number of electrolyzer cluster operations, with more concave or convex points. Short-term concave points will cause the electrolyzer to frequently shut down and start up, and short-term convex points will cause the electrolyzer to frequently start and shut down, resulting in the electrolyzer being in a frequent start-stop cycle, which seriously affects the safe operation of the electrolyzer. Therefore, in order to eliminate the concave or convex points on the curve of the planned number of electrolyzer cluster operations, for N ope (t) amend as follows:

[0082]

[0083] In the formula, k represents the time interval of the concave or convex point to be corrected, and the default value is 2, that is, the concave or convex points within half an hour are mainly corrected, and the value can also be selected according to the photovoltaic output characteristics of different regions. It is worth noting that for some scenes with drastic fluctuations in photovoltaic output, the operation of formula (9) can be performed multiple times.

[0084] Embodiment 2:

[0085] A control method for electrolyzer cluster based on photovoltaic output, assuming that the photovoltaic installed capacity of the photovoltaic hydrogen production project is 55MW, the photovoltaic prediction accuracy δ is 90%, the electrolyzer cluster consists of 10 alkaline electrolyzers, and the total power P of the public auxiliary equipment of the electrolyzer cluster is oth The rated power of a single electrolyzer is 2MW. rat The power of a single electrolyzer is 5MW, the lower limit of operation of a single electrolyzer is a=40%, and the upper limit of operation of a single electrolyzer is b=100%.

[0086] Take a typical photovoltaic output day as an example. Figure 2 As shown, the time interval for predicting output is 15 minutes.

[0087] The upper and lower limits of photovoltaic output forecast: Figure 3 As shown, based on the photovoltaic prediction accuracy, the upper and lower limits of the output taking into account the photovoltaic prediction error are obtained according to formula (2).

[0088] Number of electrolyzer clusters in operation: Based on the upper and lower limits of the photovoltaic predicted output obtained, the lower and upper limits of the number of electrolyzer clusters in operation are calculated according to formulas (3) and (4) respectively, and the data that does not meet the actual needs are processed according to formulas (5) and (6). The processed data can be used to calculate the number of electrolyzer clusters in operation through formulas (7) and (8).

[0089] like Figure 4 As shown, there is a concave point on the electrolyzer cluster operation quantity curve, which will cause the electrolyzer to shut down and start up in a short period of time, affecting the safe operation of the electrolyzer.

[0090] Correction of the number of electrolytic cell clusters in operation: Formula (9) is used to correct the concave points in the curve graph. The corrected electrolytic cell cluster operation number curve is as follows: Figure 5 shown.

[0091] Based on the corrected number of electrolyzer cluster operations, the adjustable range of the electrolyzer cluster taking into account the photovoltaic prediction error can be obtained. Figure 6 As shown, the adjustable upper and lower limits of the electrolyzer cluster can basically cover the upper and lower limits of the photovoltaic predicted output. Only when the photovoltaic output is high will there be a certain photovoltaic grid connection or photovoltaic power generation limitation.

[0092] Based on the photovoltaic prediction data, the method proposed in the present invention can be used to obtain a start-stop planning table for the electrolyzer cluster taking into account the photovoltaic prediction error, as shown in Table 1. The time intervals in the table are all 15 minutes.

[0093] The electrolyzer cluster start-stop planning table calculated based on the day-ahead photovoltaic forecast data realizes the planning of the number of electrolyzers in operation tomorrow, providing a basis and support for the next step of electrolyzer daily start-up and scheduling.

[0094] Table 1

[0095] time Number of electrolyzer clusters in operation time Number of electrolyzer clusters in operation 0:00 0 15:15 9 0:15 0 15:30 8 0:30 0 15:45 7 ··· 0 16:00 6 6:30 0 16:15 5 6:45 1 16:30 5 7:00 2 16:45 4 7:15 3 17:00 2 7:30 6 17:15 2 7:45 7 17:30 1 8:00 10 17:45 1 8:15 10 18:00 1 8:30 10 18:15 0 ··· 10 18:30 0 14:45 10 ··· 0 15:00 10 24:00 0

[0096] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for controlling an electrolyzer cluster based on photovoltaic output, characterized in that: Based on the photovoltaic prediction data, the photovoltaic prediction error and the impact of sudden increase or decrease in photovoltaic power in the short term are considered to ensure that the photovoltaic output at any time in the future prediction can be adjusted to achieve source-load balance by adjusting the load of the started electrolyzer. The number of electrolyzer cluster operations N is obtained. ope (t): (1) According to formula (7), the number of electrolytic cell clusters in operation at time t is calculated as: N ope (t)=ceil[(N lower (t)+N upper (t)) / 2] (7) Where: N lower (t) represents the lower limit of the number of electrolyzer clusters in operation; N upper (t) represents the upper limit of the number of electrolyzer clusters in operation; ceil(.) represents the rounding operation, which rounds toward positive infinity; t represents the time scale of PV prediction; (2) According to formula (8), the number of electrolytic cell clusters in operation is processed in segments: Where: N represents the total number of electrolytic cells; (3) For the concave or convex points of the electrolytic cell cluster operation quantity curve, the electrolytic cell cluster operation quantity is corrected according to formula (9): Where: k represents the time interval of considering the correction of concave or convex points.

2. The method for controlling an electrolyzer cluster based on photovoltaic output according to claim 1, characterized in that: k is equal to 2.

3. The electrolyzer cluster control method based on photovoltaic output according to claim 1 is characterized in that: For scenarios with drastic fluctuations in PV output, formula (9) is processed multiple times until the set requirements are met.

4. A method for controlling an electrolyzer cluster based on photovoltaic output according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step S1: Based on the obtained photovoltaic prediction data, the photovoltaic prediction output upper limit and output lower limit are calculated using formula (2); Where: P en (t) represents the predicted photovoltaic output; P lower (t) indicates the lower limit of output; P upper (t) indicates the upper limit of output; t represents the time scale of PV prediction; δ represents the accuracy of PV prediction data; Step S2: Calculate the upper limit and lower limit of the number of electrolytic cell cluster operations according to formula (3) and formula (4) respectively; N lower (t)=fix[(P lower (t)-P oth ) / (a*P rat )] (3) N upper (t)=ceil[(P upper (t)-P oth ) / (b*P rat )] (4) Where: N lower (t) represents the lower limit of the number of electrolyzer clusters in operation; P oth Indicates the power consumption of public and auxiliary power in the hydrogen production plant; a represents the minimum power factor for safe operation; b represents the maximum power factor for safe operation; P rat Indicates the rated power of the electrolyzer; fix(.) indicates rounding operation, rounding towards zero; N upper (t) represents the upper limit of the number of electrolyzer clusters in operation; ceil(.) represents the rounding operation, which rounds toward positive infinity; Step S3: segmenting the upper limit and lower limit of the number of electrolytic cell cluster operations according to formula (5) and formula (6); Step S4: Calculate the number of electrolytic cell clusters in operation according to formula (7); Step S5: segment the number of electrolytic cell cluster operations according to formula (8); Step S6: Correct the number of electrolytic cell cluster operations according to formula (9); Step S7: Output the number and time of electrolytic cell cluster operation.

5. The method for controlling an electrolyzer cluster based on photovoltaic output according to claim 4, characterized in that: In step S1, the safe operating range of a single electrolytic cell is: a*P rat ≤P el ≤b*P rat (1) Where: P el Indicates the operating power of a single electrolyzer; Based on formula (1) and formula (2), formula (3) and formula (4) are obtained.

6. The method for controlling an electrolyzer cluster based on photovoltaic output according to claim 4, characterized in that: In step S2, the lower limit and upper limit of the number of electrolytic cell clusters in operation are calculated by formula (3) and formula (4) respectively. If the data calculated by formula (3) and / or formula (4) is less than or equal to 0, it is considered that the data does not meet the actual demand, and the process goes to step S3, and the data is processed according to formula (5) and formula (6). The processed data is calculated by steps S4 and S5 in turn to obtain the number of electrolytic cell clusters in operation; then, for the electrolytic cell cluster operation number curve with concave or convex points, the concave or convex points are corrected by formula (9) in step S6.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method described in any one of claims 1 to 6 is implemented.

8. An electronic device, characterized in that: The invention comprises a memory and a processor; the memory stores a computer program; the processor is used to execute the computer program in the memory to implement the method according to any one of claims 1 to 6.

Images