AWE electrolytic cell-super capacitor cooperative control method
By dividing the power of the electrolytic cell into different gears and adjusting it with supercapacitors, the problem of unstable operation of the AWE electrolytic cell under wind and light power supply fluctuations is solved, and the hydrogen production efficiency and the service life of the electrolytic cell are improved.
Patent Information
- Application Number
- CN202411332090.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-24
- Publication Date
- 2024-12-17
AI Technical Summary
Under the characteristics of wind and light power supply volatility and intermittent, AWE electrolytic cells are difficult to operate stably, resulting in unstable power system and shortened electrolytic cells' life.
By dividing the power of the electrolytic cell into different gears and using supercapacitors to adjust its working state when the wind power fluctuates, the energy needs of the electrolytic cell under different loads can be met, and the smooth operation and efficient hydrogen production of the electrolytic cell are achieved.
It improves the hydrogen production efficiency and service life of the electrolytic cell, reduces the negative impact of wind power fluctuations on the electrolytic cell, and ensures the stable operation of the electrolytic cell under different load conditions.
Smart Images
Figure CN119145007A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of energy, and in particular relates to an AWE electrolyzer-supercapacitor coordinated control method. Background Art
[0002] Hydrogen energy is a clean and efficient secondary energy source. Hydrogen energy has high calorific value, abundant reserves, diverse sources, wide applications, and multiple forms of utilization. It is currently generally regarded as the most promising clean energy carrier by countries around the world. At present, there are three main electrolytic water hydrogen production technologies in electrolyzers: alkaline water electrolysis (AWE), proton exchange membrane water electrolysis (PEMWE) and solid oxide electrolyzer (SOEC). SOEC has the highest electrolysis efficiency (>90%), but has limitations such as rapid material degradation, short service life, and manufacturing cost. PEMWE has an efficiency of 65% to 82%, a relatively compact structure, and fast dynamic response, but requires expensive catalysts (such as precious metal materials Pt and Ir), and an efficiency (>90%), but has limitations such as rapid material degradation, short service life, and manufacturing cost. PEMWE has an efficiency of 65% to 82%, a relatively compact structure, and fast dynamic response, but requires expensive catalysts (such as precious metal materials Pt and Ir). AWE technology is the earliest and most mature technology among them. It does not require precious metals as catalysts, has a moderate efficiency (59-70%), a simple structure, and has the highest market share in the field of water electrolysis. However, its startup time is too long and its transient response is too slow to adapt to the fluctuation and intermittent characteristics of renewable energy. Considering the system scale, durability, and capital cost, AWE is currently the most suitable choice for commercial use. However, "green electricity" such as wind and solar power sources has strong volatility and randomness, which will have an adverse effect on the stability of the power system and the life of the electrolyzer. First, the strong random fluctuating power of "green electricity" such as wind and solar power sources will have a huge impact on the power system when it is connected to the power grid. Secondly, the input fluctuating power will reduce the performance and life of the electrolyzer. It is in this context that research on the coordinated regulation strategy of AWE hydrogen production system under fluctuating power sources is carried out. Summary of the invention
[0003] The object of the present invention is to provide an AWE electrolyzer-supercapacitor coordinated control method.
[0004] The technical solution of the present invention is as follows:
[0005] An AWE electrolyzer-supercapacitor coordinated control method, the method comprising:
[0006] Divide the power of the electrolyzer into different gears;
[0007] When wind power fluctuates, the energy demand of the electrolyzer under different load conditions is met by adjusting the working state of the supercapacitor.
[0008] Furthermore, the power of the electrolytic cell includes three gears: rated power gear P e , Medium power gear P m , low power gear P l .
[0009] Furthermore, the medium power gear P m and the low power gear P l It is set according to wind power and supercapacitor capacity.
[0010] Furthermore, the different loads include six situations: super high load, high load, medium load, low load, super low load and other loads.
[0011] Furthermore, when the electrolyzer is under ultra-high load, the following conditions are met:
[0012] P g >P h +P
[0013] At this time, the supercapacitor is running, the absorbed power of the supercapacitor is the limit power of the supercapacitor, and the actual power of the electrolyzer is:
[0014] P el =P g -P
[0015] Among them, P el is the actual operating power of the electrolytic cell, P g is the wind power, and P is the maximum power that the supercapacitor can absorb / compensate.
[0016] Furthermore, when the electrolyzer is under high load, the following conditions are met:
[0017] P h -P<P g <P h +P
[0018] At this time, the fan power is within the rated power adjustment range of the electrolyzer-supercapacitor system. Under the absorption / compensation of the supercapacitor, the electrolyzer operates stably under high power conditions. The actual operating power of the electrolyzer is:
[0019] P el =P h
[0020] Among them, Pel is the actual operating power of the electrolytic cell, P g is the wind power, and P is the maximum power that the supercapacitor can absorb / compensate.
[0021] Furthermore, when the electrolytic cell is at medium load, the following conditions are met:
[0022] P m -P<P<P m +P
[0023] At this time, the fan power is within the M-level power adjustment range of the electrolyzer-supercapacitor system. Under the absorption / compensation of the supercapacitor, the electrolyzer operates stably under the M-level power condition. The actual operating power of the electrolyzer is:
[0024] P el =P m
[0025] Among them, P el is the actual operating power of the electrolytic cell, P g is the wind power, P is the maximum power that the supercapacitor can absorb / compensate, P m It is the medium power gear of the electrolytic cell.
[0026] Furthermore, when the electrolyzer is at low load, the following conditions are met:
[0027] P l -P<P g <P l +P
[0028] At this time, the fan power is within the L-level power adjustment range of the electrolyzer-supercapacitor system. Under the absorption / compensation of the supercapacitor, the electrolyzer operates stably under the L-level power condition. The actual operating power of the electrolyzer is:
[0029] P el =P l
[0030] Among them, P el is the actual operating power of the electrolytic cell, P g is the wind power, P is the maximum power that the supercapacitor can absorb / compensate, P l It is the low power gear of the electrolytic cell.
[0031] Furthermore, when the electrolyzer is at ultra-low load, the following conditions are met:
[0032] P g <P l -P
[0033] At this time, the capacity of the supercapacitor cannot compensate for the electrolytic cell with P l The electrolyzer operates with wind power plus the compensation power of the supercapacitor. The actual operating power of the electrolyzer is:
[0034] P el =P g +P
[0035] Among them, P el is the actual operating power of the electrolytic cell, P g is the wind power, P is the maximum power that the supercapacitor can absorb / compensate, P l It is the low power gear of the electrolytic cell.
[0036] Furthermore, when the electrolyzer is in other loads, the following conditions are met:
[0037] The actual operating power of the electrolyzer is the wind power.
[0038] P el =P g
[0039] Among them, P el is the actual operating power of the electrolytic cell, P g For wind power.
[0040] Compared with the prior art, the present invention has the following advantages:
[0041] After the operating power of the electrolyzer is graded, the supercapacitor serves the electrolyzers of different power levels, which is beneficial to the stable operation of the electrolyzer and improves the hydrogen production efficiency of the electrolyzer. BRIEF DESCRIPTION OF THE DRAWINGS
[0042] The accompanying drawings generally illustrate various embodiments by way of example and not limitation, and together with the description and claims, serve to illustrate the embodiments of the invention. Where appropriate, the same reference numerals are used throughout the drawings to refer to the same or similar parts. Such embodiments are illustrative and are not intended to be exhaustive or exclusive embodiments of the present apparatus or method.
[0043] Figure 1 A schematic diagram of the optimized simple electrolyzer-supercapacitor synergistic strategy of the present invention is shown;
[0044] Figure 2 The power diagram of a 2MW wind turbine in northwest China on a certain day is shown in the present invention (the horizontal axis is time, and the vertical axis is power kw);
[0045] Figure 3 The hourly power diagram of a 2Mw wind turbine in northwest China of the present invention is shown (the horizontal axis is time, and the vertical axis is power kw);
[0046] Figure 4 A schematic diagram of relevant parameters of an electrolytic cell in an embodiment of the present invention is shown;
[0047] Figure 5 A schematic diagram of simulation results of a simple electrolyzer-supercapacitor coordinated control strategy of the present invention is shown;
[0048] Figure 6 A schematic diagram of simulation results of the optimized simple electrolyzer-supercapacitor coordinated control strategy of the present invention is shown. DETAILED DESCRIPTION
[0049] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.
[0050] The embodiment of the present invention provides an AWE electrolyzer-supercapacitor coordinated control method,
[0051] When the difference between the fan output power and the rated power of the electrolyzer is too large, the supercapacitor loses the ability to smooth out power supply fluctuations, which cannot meet the requirements of "reducing the negative impact of fluctuating power supply on the electrolyzer, and improving the life safety and hydrogen production efficiency of the electrolyzer".
[0052] First, the power of the electrolyzer is divided into three gears: rated power gear (P e ), medium power gear (P m ), low power gear (P l ). These gear settings are not only based on the rated power of the electrolyzer, but also take into account the local wind level and the capacity of the supporting supercapacitor. By dividing the power of the electrolyzer into different gears, we can dynamically adjust the working state of the supercapacitor according to the actual local wind conditions to meet the energy needs of the electrolyzer under different load conditions.
[0053] Under high load conditions, when the fan power exceeds the absorption range of the electrolyzer, the supercapacitor will absorb excess electrical energy to prevent the electrolyzer from overloading for a long time, thus affecting the life of the electrolyzer. In this case, the supercapacitor plays the role of a buffer and regulator of electrical energy, ensuring that the electrolyzer can operate stably and extending its service life. When the fan output power is less than the rated power of the electrolyzer, the supercapacitor can compensate for the energy demand of the electrolyzer by discharging, ensuring the continuous production of hydrogen, while stabilizing the operation of the electrolyzer and extending the service life of the electrolyzer.
[0054] However, when the wind power fluctuates violently, that is, when the wind power exceeds the ability of the supercapacitor to regulate the electrolyzer to operate at rated power, the electrolyzer should adjust the power level and downgrade to medium power (Pm ) gear. In the simple electrolyzer-supercapacitor synergy strategy, the service power of the supercapacitor should not be the rated power but should be adjusted based on the medium power level. If the fan power is higher than the medium power, the supercapacitor will start and absorb the excess power to maintain the stable operation of the electrolyzer. Conversely, if the fan power is lower than the medium power, the supercapacitor will start and compensate the electrolyzer energy to ensure that it can maintain stable operation under fluctuating power supply.
[0055] In some special cases, such as when the wind power is low, the wind turbine power fluctuates at a low power level for a long time, and the electrolyzer is adjusted to a low power gear (P l ), running smoothly at a lower power. This ensures that the electrolyzer can operate normally even when the load is low. When the fan power is higher than the low power level, the supercapacitor will absorb the excess power to allow the electrolyzer to operate smoothly. When the fan power is not enough to meet the energy needs of the electrolyzer, the supercapacitor will discharge to compensate for the energy of the electrolyzer to ensure hydrogen production efficiency and its stable operation.
[0056] It should be noted that the rated power of the electrolyzer (P e ), the ultracapacitor's maximum power (P), the medium power gear (P m ) and low power gear (P l ) must be reasonable and appropriate. Their choice is multifaceted, and the most important factor affecting it is the local wind level. The richer the local wind resources, the greater the rated power of the electrolyzer should be. In this optimization synergy strategy, the maximum power of the supercapacitor should theoretically be as large as possible, because if the capacity of the supercapacitor is large enough, as long as the appropriate rated power of the electrolyzer is selected, the electrolyzer can always operate at the rated power, because the supercapacitor can continuously absorb / compensate the electrolyzer's electrical energy, but this is obviously impossible in reality.
[0057] Medium power gear (P m ) and low power gear (P l ) is related to the local wind level and the capacity of the supercapacitor. If the local wind level is high and always fluctuates at a higher level, then the medium power gear (P m ) and low power gear (P l If the local wind level is low and often fluctuates at a lower level, then the medium power gear (P m ) and low power gear (P l At the same time, the wind level in some places is seasonal. In actual situations, we can set a higher medium power gear (Pm ) and low power gear (P l ), set a lower medium power gear (P m ) and low power gear (P l ). Medium power gear (P m ) and low power gear (P l ) should be a variable parameter depending on the situation, and is a setting that we need to adjust according to the local seasonal wind energy fluctuations. In addition, the medium power gear (P m ) and low power gear (P l ) should not be set too low, because in this optimized simple electrolyzer-supercapacitor synergy strategy, when the electrolyzer is in the medium power gear (P m ) and low power gear (P l ) During operation, the supercapacitor will absorb wind power greater than this power level, which is not conducive to the efficiency of hydrogen production by the electrolyzer. In short, the overall goal is to enable the electrolyzer to operate stably under different conditions while improving the hydrogen production efficiency of the electrolyzer.
[0058] Case 1: Extremely high load, the system needs to meet the conditions
[0059] P g >P h +P
[0060] At this time, the supercapacitor is running, and the absorbed power of the supercapacitor is the limit power of the supercapacitor, Psc = P, and the influence of overload on the electrolyzer is reduced as much as possible. The actual power of the electrolyzer is
[0061] P el =P g -P
[0062] Case 2: High load, the system needs to meet the conditions
[0063] P h -P<P g <P h +P
[0064] At this time, the fan power is within the rated power adjustment range of the electrolyzer-supercapacitor system, and the electrolyzer operates stably under the rated power (high power) condition under the absorption / compensation of the supercapacitor.
[0065] The actual operating power of the electrolyzer is
[0066] P el =P h
[0067] Case 3: Medium load, the system needs to meet the conditions
[0068] P m -P<P<P m +P
[0069] At this time, the fan power is within the M-level power adjustment range of the electrolyzer-supercapacitor system, and the electrolyzer operates stably under the M-level power condition under the absorption / compensation of the supercapacitor.
[0070] The actual operating power of the electrolyzer is
[0071] P el =P m
[0072] Case 4: Low load, the system needs to meet the conditions
[0073] P l -P<P g <P l +P
[0074] At this time, the fan power is within the L-level power adjustment range of the electrolyzer-supercapacitor system. Under the absorption / compensation of the supercapacitor, the electrolyzer operates stably under the L-level power condition. The actual operating power of the electrolyzer is
[0075] P el =P l
[0076] Case 5: Ultra-low load, the system needs to meet the conditions
[0077] P g <P l -P
[0078] At this time, because the capacity limit of the supercapacitor cannot compensate the electrolyzer to operate at P1 power, the electrolyzer operates at the wind power plus the compensation power of the supercapacitor. The actual operating power of the electrolyzer is:
[0079] P el =P g +P
[0080] Case 6: Other loads, the fan power is within the ultra-high load and ultra-low load range, but not within the high, medium and low load adjustment range. In this case, the actual operating power of the electrolyzer is the power delivered by the fan.
[0081] P el =P g
[0082] The above six situations are optimization solutions for the simple electrolyzer-supercapacitor system. After the operating power of the electrolyzer is graded, the supercapacitor serves electrolyzers of different power levels. This will be conducive to the smooth operation of the electrolyzer and improve the hydrogen production efficiency of the electrolyzer.
[0083] Example 1
[0084] Taking the output data of a 2Mw wind turbine in the northwest of China as an example, the simulation application was carried out in the software MATLAB. At the same time, we compared the hydrogen production of the electrolyzer without any optimization strategy, the simple electrolyzer-supercapacitor synergy strategy, and the optimized simple electrolyzer-supercapacitor synergy strategy.
[0085] The output power of a 2Mw wind turbine in northwest China in one day is selected as the research object. The output power of a 2Mw wind turbine in northwest China in one hour is as follows: Figure 3 The relevant parameters of the electrolytic cell used in this paper are shown in Figure 4 Here, in order to simplify the model, the working temperature of the electrolyzer is set to be constant at 40°C, and the limit power of the supercapacitor is 0.25Mw. According to the overload characteristics of the electrolyzer, and considering the capacity level of the electrolyzer in actual situations, the overload factor of the electrolyzer array is set to 110%, thereby obtaining the configured electrolyzer capacity of the electrolyzer and the rated power of the electrolyzer.
[0086]
[0087] Combining the wind power and the supercapacitor limit power, the supercapacitor limit power P=150Kw, the electrolytic cell medium power Pm=1600kw, and the electrolytic cell low power Pl=1300Kw are set.
[0088] The hydrogen production efficiency of the simple electrolyzer-supercapacitor coordinated control strategy is 9.01 mol / s (simulation results are shown in Figure 5 )
[0089] The hydrogen production efficiency of the simple electrolyzer-supercapacitor coordinated control strategy of the present invention is 9.1 mol / s (simulation results are shown in Figure 6 )
[0090] At this time, the hydrogen production rate of the optimized strategy is higher, indicating that the optimized strategy is feasible and effective.
[0091] The power of the electrolyzer without any optimization strategy changes with the change of wind power, and the hydrogen production efficiency also changes accordingly. Supercapacitors are not used for "peak shaving and valley filling". Because the part of the wind turbine power that is higher than the rated power of the electrolyzer is not "cut", the hydrogen production efficiency of the electrolyzer without any optimization strategy will not be too low. When the wind turbine power fluctuates greatly, the operating power and hydrogen production efficiency of the electrolyzer will also fluctuate greatly, which will have an adverse effect on the operating safety and service life of the electrolyzer.
[0092] By applying a simple electrolyzer-supercapacitor optimization synergy strategy, it can be clearly seen that the operating power and hydrogen production efficiency of the electrolyzer have always been running at the rated power within the range where the fan power is close to the rated power of the electrolyzer, and are constant and stable. This simple optimization strategy is feasible to a certain extent and is suitable for applications where the fan output power fluctuates at a higher power level for a long time. When the fan power level fluctuates at a low level and low load, the electrolyzer-supercapacitor synergy strategy loses its regulatory function. It will become like no optimization strategy is applied.
[0093] By applying the electrolytic cell-supercapacitor optimization synergy strategy of the present invention, it can be clearly seen from the figure that under the regulation of the supercapacitor, the electrolytic cell is basically at rated power and medium-level gear power operation. This is very conducive to the smooth and safe operation of the electrolytic cell. It also expands the load width during the low-load period.
[0094] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.
Claims
1. A method for coordinated control of an AWE electrolyzer and a supercapacitor, characterized in that: The method comprises: Divide the power of the electrolyzer into different gears; When wind power fluctuates, the energy demand of the electrolyzer under different load conditions is met by adjusting the working state of the supercapacitor.
2. The AWE electrolyzer-supercapacitor coordinated control method according to claim 1, characterized in that: The power of the electrolytic cell is divided into three gears: rated power gear P e , Medium power gear P m , low power gear P l .
3. The AWE electrolyzer-supercapacitor coordinated control method according to claim 2, characterized in that: The medium power gear P m and the low power gear P l It is set according to wind power and supercapacitor capacity.
4. The AWE electrolyzer-supercapacitor coordinated control method according to claim 1, characterized in that: The different loads include six situations: super high load, high load, medium load, low load, super low load and other loads.
5. The AWE electrolyzer-supercapacitor coordinated control method according to claim 4, characterized in that: When the electrolyzer is under ultra-high load, the following conditions are met: P g >P h +P At this time, the supercapacitor is running, the absorbed power of the supercapacitor is the limit power of the supercapacitor, and the actual power of the electrolyzer is: P el =P g -P Among them, P el is the actual operating power of the electrolytic cell, P g is the wind power, and P is the maximum power that the supercapacitor can absorb / compensate.
6. The AWE electrolyzer-supercapacitor coordinated control method according to claim 4, characterized in that: When the electrolyzer is under high load, the following conditions are met: P h -P<P g <P h +P At this time, the fan power is within the rated power adjustment range of the electrolyzer-supercapacitor system. Under the absorption / compensation of the supercapacitor, the electrolyzer operates stably under high power conditions. The actual operating power of the electrolyzer is: P el =P h Among them, P el is the actual operating power of the electrolytic cell, P g is the wind power, and P is the maximum power that the supercapacitor can absorb / compensate.
7. The AWE electrolyzer-supercapacitor coordinated control method according to claim 4, characterized in that: When the electrolytic cell is at medium load, the following conditions are met: P m -P<P<P m +P At this time, the fan power is within the M-level power adjustment range of the electrolyzer-supercapacitor system. Under the absorption / compensation of the supercapacitor, the electrolyzer operates stably under the M-level power condition. The actual operating power of the electrolyzer is: P el =P m Among them, P el is the actual operating power of the electrolytic cell, P g is the wind power, P is the maximum power that the supercapacitor can absorb / compensate, P m It is the medium power gear of the electrolytic cell.
8. The AWE electrolyzer-supercapacitor coordinated control method according to claim 4, characterized in that: When the electrolyzer is at low load, the following conditions are met: P l -P<P g <P l +P At this time, the fan power is within the L-level power adjustment range of the electrolyzer-supercapacitor system. Under the absorption / compensation of the supercapacitor, the electrolyzer operates stably under the L-level power condition. The actual operating power of the electrolyzer is: P el =P l Among them, P el is the actual operating power of the electrolytic cell, P g is the wind power, P is the maximum power that the supercapacitor can absorb / compensate, P l It is the low power gear of the electrolytic cell.
9. The AWE electrolyzer-supercapacitor coordinated control method according to claim 4, characterized in that: When the electrolyzer is at ultra-low load, the following conditions are met: P g <P l -P At this time, the capacity of the supercapacitor cannot compensate for the electrolytic cell with P l The electrolyzer operates with wind power plus the compensation power of the supercapacitor. The actual operating power of the electrolyzer is: P el =P g +P Among them, P el is the actual operating power of the electrolytic cell, P g is the wind power, P is the maximum power that the supercapacitor can absorb / compensate, P l It is the low power gear of the electrolytic cell.
10. The AWE electrolyzer-supercapacitor coordinated control method according to claim 4, characterized in that: When the electrolytic cell is under other loads, the following conditions are met: The actual operating power of the electrolyzer is the wind power. P el =P g Among them, P el is the actual operating power of the electrolytic cell, P g For wind power.