A multi-mode flexible switching light-hydrogen complementary simulation experimental method and system

Abstract

The present invention provides a multi-mode flexible switching solar-hydrogen complementarity simulation experiment method and system, relating to the field of renewable energy consumption technology. The method comprises: designing system capacity configuration and establishing a series of mathematical models, including a photovoltaic power generation mathematical model, a hydrogen fuel cell mathematical model, and an electrolyzer mathematical model; designing a multi-mode simulation experiment function based on the capacity configuration design, taking into account operational objectives such as efficient energy utilization, suppressing power fluctuations, and achieving flexible grid dispatch; and proposing a multi-mode flexible switching collaborative control strategy, experimental steps, and methods based on the simulation experiment function and multi-mode design, and conducting simulation verification based on the MATLAB platform. The system can accurately respond to power regulation requirements in different modes, achieving multi-energy complementarity and coordinated operation. It provides technical support for solving the problem of intermittent renewable energy consumption and plays a good supporting role in the safe and economic operation of power systems with a high proportion of intermittent renewable energy generation.

Description

Technical Field

[0001] The present invention relates to the field of renewable energy consumption technology, and in particular to a multi-mode flexible switching light-hydrogen complementary simulation experiment method and system. Technical Background

[0002] The development of renewable energy generation is an inevitable trend, and multi-energy coupling will provide a crucial foundation for the development of new energy power. Photovoltaic power generation is a renewable energy technology with advantages such as a simple power generation process, no fuel consumption, no emissions (including greenhouse gases), and no noise or pollution. It is a technology with the most ideal characteristics for sustainable development. However, the use of renewable energy generation technologies is often intermittent and volatile, and is significantly affected by uncontrollable factors such as weather. When renewable energy generation exceeds the local power grid's capacity, it can easily lead to curtailment, resulting in a serious waste of renewable energy resources.

[0003] With the accelerated development of renewable energy, multi-energy coupling will achieve mutually beneficial development for renewable energy and hydrogen. Hydrogen, as a clean and efficient energy source, boasts large capacity, long lifespan, and ease of storage and transmission. Solar-hydrogen complementarity can leverage their respective strengths, promote the absorption of new energy, and effectively resolve the conflict between the high proportion of intermittent and fluctuating renewable energy and rigid loads, ensuring the safe and stable operation of the new power system. Currently, research on multi-energy coupling is relatively limited and still in its infancy. Furthermore, grid-powered models are rarely considered in this research. Summary of the Invention

[0004] In order to solve the above problems, the present invention proposes a multi-mode flexible switching light-hydrogen complementary simulation experimental method and system, which comprehensively considers various energy conversion mechanisms and complementary characteristics, utilizes the hydrogen energy storage characteristics to fully tap the proportion of renewable resource power generation in the power supply of the power grid, and improves the consumable capacity.

[0005] A multi-mode flexible switching solar-hydrogen complementary simulation experiment method can maximize energy utilization and storage in different operating modes. The simulation experiment method includes three parts: capacity configuration design, simulation experiment function and multi-mode design, and simulation experiment steps and methods. The specific steps are as follows:

[0006] Step 1: Design the system capacity configuration and establish a series of mathematical models including photovoltaic power generation mathematical model, hydrogen fuel cell mathematical model, electrolyzer mathematical model, etc.

[0007] Step 2: Based on the capacity configuration design, multi-mode simulation experiment functions are designed while fully considering the operational goals such as efficient energy utilization, suppressing power fluctuations, and achieving flexible grid scheduling.

[0008] Step 3: Based on the simulation experiment function and multi-mode design, a multi-mode flexible switching collaborative control strategy and experimental steps and methods are proposed, and simulation verification is carried out based on the MATLAB platform.

[0009] Furthermore, the step 1 specifically includes:

[0010] Fuel cell simulation capacity configuration: Total capacity ≥ 50kW. The fuel cells are divided into two groups: The first group consists of 300 fuel cell stacks, with a single stack voltage of 1.2041V. The rated current is 100A, the rated voltage is 500V, the rated power is 50kW, the rated hydrogen supply pressure is 1.5bar, the rated oxygen supply pressure is 1bar, and the maximum output voltage is 600V. The second group consists of 70 fuel cell stacks, with a single stack voltage of 1.2113V. The rated current is 40A, the rated voltage is 500V, the rated power is 20kW, the rated hydrogen supply pressure is 1.5bar, the rated oxygen supply pressure is 1bar, and the maximum output voltage is 600V.

[0011] Simulated photovoltaic power supply capacity configuration: Total capacity ≥ 50kW, consisting of 17 photovoltaic modules connected in series and parallel. A single photovoltaic module string is formed by 14 photovoltaic arrays connected in series. The short-circuit current of a single photovoltaic array is 7.84A. The rated current is 125A, the rated voltage is 400V, and the maximum output voltage is 508.2V.

[0012] Electrolytic cell simulation capacity configuration: total capacity ≥50kW, the electrolytic cells are divided into two groups: the first group consists of 200 electrolytic cells, with a single cell reversible voltage of 1.23V, an electrode area of ​​0.1㎡, a rated current of 125A, and a rated voltage of 400V; the second group consists of 100 electrolytic cells, with a single cell reversible voltage of 1.23V, an electrode area of ​​0.1㎡, a rated current of 50A, and a rated voltage of 400V.

[0013] PV inverter parameters: grid-connected rated voltage 800V, grid-side frequency 50Hz, THD≤5%, AC voltage 380VAC, MPPT voltage range 200-950V, power factor 1.

[0014] Fuel cell inverter parameters: grid-connected rated voltage 800V, grid-side frequency 50Hz, THD≤5%, AC voltage 380VAC, power factor 1.

[0015] Electrolyzer converter parameters: DC rated voltage 800VDC, grid-side frequency 50Hz, THD≤5%, AC voltage 380VAC, power factor 1.

[0016] (1) Mathematical model of photovoltaic power generation:

[0017] I=Ipv -I d

[0018]

[0019]

[0020] Where, I pv is the current generated by the photovoltaic cell due to solar radiation; I0 is the saturation current; I is the load current; V is the photovoltaic output voltage; R S is the series impedance of the photovoltaic cell; α is the time factor.

[0021] (2) Hydrogen fuel cell mathematical model:

[0022] U fc =U oc -U ohm -U act

[0023]

[0024] U ohm =R ohm ·i fc

[0025]

[0026] Where U fc is the fuel cell output voltage; U oc is the open circuit voltage of the fuel cell, U ohm is the ohmic overvoltage loss, U act is the absolute polarization voltage loss; K c is the voltage constant under nominal working conditions; E0 is the electromotive force under standard pressure; T f is the operating temperature of the fuel cell; z is the number of moving electrons; F is the Faraday constant; R is the gas constant; is the hydrogen partial pressure in the pile; is the partial pressure of oxygen in the pile; is the partial pressure of water vapor in the pile; R ohm is the equivalent internal resistance; i fc is the fuel cell current; N fc is the number of fuel cells; A is the Tafel slope; i0 is the exchange current; T fc is the response time.

[0027] (3) Electrolytic cell mathematical model:

[0028]

[0029]

[0030]

[0031] Where U el is the working voltage of a single electrolytic cell; U r is the reversible voltage; A el is the electrode area; T el is temperature; I el is the current; r1 and r2 are the ohmic resistance parameters; s and k T1 、k T2 、k T3 is the overvoltage coefficient; is the hydrogen production rate; η e is the electrolytic cell efficiency; N e is the number of electrolytic cells; F is the Faraday constant; P e is the power consumed.

[0032] (4) Boost converter mathematical model:

[0033]

[0034] Where: i1 is the inductor current; V out1 is the output voltage; V in1 is the input voltage and D1 is the control signal.

[0035] (5) Buck converter mathematical model:

[0036]

[0037] Where: i2 is the inductor current; V in2 is the input voltage; V out2 is the output voltage and d is the control signal.

[0038] Furthermore, the step 2 specifically includes:

[0039] Set P PV is the output power of photovoltaic power generation, P load is the load demand power, P s =P PV -P load is the remaining power, P grid is the power demanded by the grid, P fc is the output power of fuel cell power generation, P ele Power consumed by the electrolytic cell.

[0040] Mode 1: P s ≥0, P grid >0, P grid ≥P s , at this time P fc =P grid -Ps , P ele = 0. When photovoltaic power generation can meet the load demand but cannot meet the grid demand, the fuel cell will provide the required energy as a backup power source and the electrolysis cell will stop operating.

[0041] Mode 2: P s ≥0, P grid >0, P grid <P s , at this time P fc =0,P ele =P s -P grid When photovoltaic power generation can meet both load demand and grid demand, the fuel cell stops running and the remaining energy is used to produce hydrogen in the electrolysis cell.

[0042] Mode 3: P s ≥0, P grid =0, at this time P fc =0,P ele =P s When photovoltaic power generation meets the load demand and there is no grid demand, the fuel cell stops running and the remaining energy is used to produce hydrogen in the electrolysis cell.

[0043] Mode 4: P s ≥0, P grid <0, at this time P fc =0,P ele =P s +|P grid When photovoltaic power generation meets load demand and the grid has excess power, the fuel cell stops operating and the remaining energy is used to produce hydrogen in the electrolyzer.

[0044] Mode 5: P s <0, P grid >0, then P fc =P grid +|P s |,P ele = 0. When photovoltaic power generation cannot meet the load demand and grid demand, the fuel cell will provide the required energy as a backup power source and the electrolysis cell will stop operating.

[0045] Mode 6: P s <0, P grid =0, at this time P fc =|P s |,P ele = 0. When photovoltaic power generation can meet the load demand and there is no grid demand, the fuel cell will provide the required energy as a backup power source and the electrolysis cell will stop operating.

[0046] Mode 7: P s <0, P grid<0,|P grid |≥|P s |, at this time P fc =0,P ele =|P grid |-|P s When photovoltaic power generation cannot meet the load demand and there is excess grid power in the system, the fuel cell stops running and the remaining energy is used to produce hydrogen in the electrolysis cell.

[0047] Mode 8: P s <0, P grid <0,|P grid |<|P s |, at this time P fc =|P s |-|P grid |,P ele = 0. When photovoltaic power generation cannot meet the load demand and there is excess power in the grid, and the combined effect of the two still cannot meet the load demand, the fuel cell will provide the required energy as a backup power source and the electrolysis cell will stop operating.

[0048] Furthermore, the step 3 specifically includes:

[0049] In the present invention, the grid-connected inverter control strategy adopts voltage and current double closed-loop control to control the DC bus U dc The photovoltaic power generation control strategy uses maximum power point tracking technology to track the maximum power point by comparing the instantaneous conductance of the photovoltaic power generation with the change in conductance, ensuring maximum utilization of the photovoltaic power generation power. Fuel cell control includes power control and current control. Hydrogen fuel cells are based on the fuel cell characteristic curve. By changing the output current of the fuel cell stack, the fuel cell stack port voltage and output power can be adjusted. The electrolyzer control strategy is divided into rectification control and power control. When the power supply is sufficient or there is surplus, the excess power is supplied to the electrolyzer equipment, increasing hydrogen production and improving energy utilization. When the power supply is tight or even insufficient, the electrolyzer equipment will reduce hydrogen production or suspend operation. Its control strategy is similar to that of hydrogen fuel cells, both of which are power control.

[0050] Taking into account signal delay and equipment startup, the simulation experiment optimized the power control signal of the fuel cell equipment and electrolyzer equipment on the original basis. The power prediction value P(t+1) comprehensively considers the weighted signals of each module at the previous N+1 moments, among which the predicted value of the fuel cell power at time t+1 P fc (t+1) is:

[0051]

[0052] Where, P is the dynamic adjustment coefficient of the power signal of the power grid at time ti; grid (ti) is the grid power at time ti; P is the dynamic adjustment coefficient of the load power signal at time ti; grid (ti) is the load power at time ti; is the dynamic adjustment coefficient of the photovoltaic power signal at time ti; P pv (ti) is the photovoltaic power at time ti.

[0053] The predicted value P of the electrolytic cell power at time t+1 ele (t+1) is:

[0054]

[0055] To improve the utilization efficiency of hydrogen fuel cells and electrolyzers, two sets of equipment with different power ratings are prepared. These are divided into two tiers based on power demand: tier one and tier two. In tier one, the fuel cell's rated power is 20kW, and the electrolyzer's rated power is 20kW; in tier two, the fuel cell's rated power is 50kW, and the electrolyzer's rated power is 50kW. In multi-mode operation, tier one equipment is activated if the fuel cell's output power and the electrolyzer's power consumption are within 30kW; tier two equipment is activated if the fuel cell's output power and the electrolyzer's power consumption exceed 30kW.

[0056] A multi-mode, flexible switching solar-hydrogen complementary simulation system includes a photovoltaic power generation module, a load module, and a hydrogen energy module. The hydrogen energy module includes a hydrogen fuel cell power generation module and an electrolysis hydrogen production module.

[0057] Beneficial effects of the present invention:

[0058] Based on the law of conservation of energy, ignoring losses caused by energy conversion and transmission, the hydrogen fuel cell and electrolyzer quickly track the flexible regulation needs of the photovoltaic grid-connected system under different modes. Simulations conducted on the MATLAB platform have verified that this multi-mode flexible switching solar-hydrogen complementary simulation method and system can accurately respond to power regulation requirements under different modes, achieving multi-energy complementarity and coordinated operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a typical structural diagram of the present invention.

[0060] Figure 2 This is a multi-mode flexible switching design diagram of the present invention.

[0061] Figure 3 This is a multi-mode simulation experiment data diagram of the present invention.

[0062] Figure 4It is a simulation experiment result diagram of the collaborative operation of the present invention. DETAILED DESCRIPTION

[0063] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail with reference to the following embodiments and accompanying drawings.

[0064] Figure 1 This is a typical structural diagram of the simulation system. The model structure is as follows Figure 1 As shown, it includes photovoltaic power generation model, hydrogen fuel cell model, electrolyzer model, etc. Figure 2 It is a multi-mode flexible switching design diagram. Figure 3 This is a multi-mode simulation experiment data diagram. The initial simulation experiment data corresponds to each mode one by one. Based on this simulation experiment data, the MATLAB platform is used to simulate and verify the flexible switching of the light-hydrogen complementary system under multiple modes. Figure 4 This is the result of the collaborative simulation experiment. It includes the following steps:

[0065] Step 1: Design the capacity configuration of the system and establish a series of mathematical models including photovoltaic power generation mathematical model, hydrogen fuel cell mathematical model, electrolyzer mathematical model, etc. Figure 1 As shown in the figure, a multi-energy complementary light-hydrogen system including photovoltaic power generation module, load module and hydrogen energy module is established. Among them, the hydrogen energy module includes a hydrogen fuel cell power generation module and an electrolysis hydrogen production module, which respectively model photovoltaic power generation, fuel cell, electrolysis hydrogen production, etc.

[0066] Specifically, step 1 includes the following steps:

[0067] Fuel cell simulation capacity configuration: Total capacity ≥ 50kW. The fuel cells are divided into two groups: The first group consists of 300 fuel cell stacks, with a single stack voltage of 1.2041V. The rated current is 100A, the rated voltage is 500V, the rated power is 50kW, the rated hydrogen supply pressure is 1.5bar, the rated oxygen supply pressure is 1bar, and the maximum output voltage is 600V. The second group consists of 70 fuel cell stacks, with a single stack voltage of 1.2113V. The rated current is 40A, the rated voltage is 500V, the rated power is 20kW, the rated hydrogen supply pressure is 1.5bar, the rated oxygen supply pressure is 1bar, and the maximum output voltage is 600V.

[0068] Simulated photovoltaic power supply capacity configuration: Total capacity ≥ 50kW, consisting of 17 photovoltaic modules connected in series and parallel. A single photovoltaic module string is formed by 14 photovoltaic arrays connected in series. The short-circuit current of a single photovoltaic array is 7.84A. The rated current is 125A, the rated voltage is 400V, and the maximum output voltage is 508.2V.

[0069] Electrolytic cell simulation capacity configuration: total capacity ≥50kW, the electrolytic cells are divided into two groups: the first group consists of 200 electrolytic cells, with a single cell reversible voltage of 1.23V, an electrode area of ​​0.1㎡, a rated current of 125A, and a rated voltage of 400V; the second group consists of 100 electrolytic cells, with a single cell reversible voltage of 1.23V, an electrode area of ​​0.1㎡, a rated current of 50A, and a rated voltage of 400V.

[0070] PV inverter parameters: grid-connected rated voltage 800V, grid-side frequency 50Hz, THD≤5%, AC voltage 380VAC, MPPT voltage range 200-950V, power factor 1.

[0071] Fuel cell inverter parameters: grid-connected rated voltage 800V, grid-side frequency 50Hz, THD≤5%, AC voltage 380VAC, power factor 1.

[0072] Electrolyzer converter parameters: DC rated voltage 800VDC, grid-side frequency 50Hz, THD≤5%, AC voltage 380VAC, power factor 1.

[0073] (1) Mathematical model of photovoltaic power generation:

[0074] I=I pv -I d

[0075]

[0076]

[0077] Where, I pv is the current generated by the photovoltaic cell due to solar radiation; I0 is the saturation current; I is the load current; V is the photovoltaic output voltage; R S is the series impedance of the photovoltaic cell; α is the time factor.

[0078] (2) Hydrogen fuel cell mathematical model:

[0079] U fc =U oc -U ohm -U act

[0080]

[0081] U ohm =R ohm ·i fc

[0082]

[0083] Where Ufc is the fuel cell output voltage; U oc is the open circuit voltage of the fuel cell, U ohm is the ohmic overvoltage loss, U act is the absolute polarization voltage loss; K c is the voltage constant under nominal working conditions; E0 is the electromotive force under standard pressure; T f is the operating temperature of the fuel cell; z is the number of moving electrons; F is the Faraday constant; R is the gas constant; is the hydrogen partial pressure in the pile; is the partial pressure of oxygen in the pile; is the partial pressure of water vapor in the pile; R ohm is the equivalent internal resistance; i fc is the fuel cell current; N fc is the number of fuel cells; A is the Tafel slope; i0 is the exchange current; T fc is the response time.

[0084] (3) Electrolytic cell mathematical model:

[0085]

[0086]

[0087]

[0088] Where U el is the working voltage of a single electrolytic cell; U r is the reversible voltage; A el is the electrode area; T el is temperature; I el is the current; r1 and r2 are the ohmic resistance parameters; s and k T1 、k T2 、k T3 is the overvoltage coefficient; is the hydrogen production rate; η e is the electrolytic cell efficiency; N e is the number of electrolytic cells; F is the Faraday constant; P e is the power consumed.

[0089] (4) Boost converter mathematical model:

[0090]

[0091] Where: i1 is the inductor current; V out1 is the output voltage; V in1 is the input voltage and D1 is the control signal.

[0092] (5) Buck converter mathematical model:

[0093]

[0094] Where: i2 is the inductor current; V in2 is the input voltage; V out2 is the output voltage and d is the control signal.

[0095] Step 2: Based on the capacity configuration design, design the multi-mode simulation experiment function while fully considering the operation goals such as efficient energy utilization, suppression of power fluctuations and realization of flexible grid dispatch. Figure 2 As shown in the figure, the mode is designed according to the photovoltaic power generation situation, grid operation status and load demand.

[0096] Specifically, step 2 includes the following steps:

[0097] P PV is the output power of photovoltaic power generation, P load is the load demand power, P s =P PV -P load is the remaining power, P grid is the power demanded by the grid, P fc is the output power of fuel cell power generation, P ele Power consumed by the electrolytic cell.

[0098] In the solar-hydrogen complementary system, the impact of grid demand is usually ignored. Whether the grid has surplus power or insufficient power supply, it will cause harm to the power system. Therefore, when designing the model, we focus on considering the changes in grid demand, which is divided into three situations: grid surplus power (P grid <0)、Grid supply and demand balance (P grid =0) and insufficient power supply from the grid (P grid >0). The following is the specific mode design:

[0099] Mode 1: P s ≥0, P grid >0, P grid ≥P s , at this time P fc =P grid -P s , P ele = 0. When photovoltaic power generation can meet load demand but cannot meet grid demand, the fuel cell provides the required energy as a backup power source, and the electrolysis cell stops operating. At this time, the photovoltaic module and fuel cell module jointly generate power, achieving system stability and power balance.

[0100] Mode 2: P s ≥0, P grid >0, P grid<P s , at this time P fc =0,P ele =P s -P grid When photovoltaic power generation can meet both load and grid demand, the fuel cell stops operating and the remaining energy is used to produce hydrogen in the electrolytic cell. At this point, the electrolytic cell consumes the remaining solar energy, thereby improving the new energy absorption capacity and system stability.

[0101] Mode 3: P s ≥0, P grid =0, at this time P fc =0,P ele =P s When photovoltaic power generation meets load demand and the grid is balanced, the fuel cell stops operating and the remaining energy is used to produce hydrogen in the electrolytic cell. At this time, the electrolytic cell consumes the remaining solar energy, thereby improving the new energy absorption capacity and system stability.

[0102] Mode 4: P s ≥0, P grid <0, at this time P fc =0,P ele =P s +|P grid When photovoltaic power generation meets load demand and the grid has surplus power, the fuel cell stops operating, and the remaining energy is used to produce hydrogen in the electrolytic cell. At this point, the electrolytic cell consumes excess solar energy and grid power, thereby improving the absorption capacity of new energy and system stability.

[0103] Mode 5: P s <0, P grid >0, then P fc =P grid +|P s |,P ele = 0. When photovoltaic power generation cannot meet load and grid demands, the fuel cell, acting as a backup power source, provides the required energy, and the electrolysis cell stops operating. At this point, the photovoltaic and fuel cell modules combine to generate power, achieving system stability and power balance.

[0104] Mode 6: P s <0, P grid =0, at this time P fc =|P s |,P ele = 0. When photovoltaic power generation can meet the load demand and there is no grid demand, the fuel cell will provide the required energy as a backup power source, and the electrolysis cell will stop operating. At this time, the photovoltaic module and fuel cell module jointly generate electricity, achieving system stability and power balance.

[0105] Mode 7: P s<0, P grid <0,|P grid |≥|P s |, at this time P fc =0,P ele =|P grid |-|P s When photovoltaic power generation fails to meet load demand and there is excess grid power in the system, the fuel cell stops operating and the remaining energy is used to produce hydrogen in the electrolyzer. This process consumes grid power, improving system stability.

[0106] Mode 8: P s <0, P grid <0,|P grid |<|P s |, at this time P fc =|P s |-|P grid |,P ele = 0. When photovoltaic power generation cannot meet the load demand and there is excess grid power in the system, and the combined effect of the two still cannot meet the load demand, the fuel cell will provide the required energy as a backup power source, and the electrolysis cell will stop operating. At this time, the photovoltaic module and fuel cell module will jointly generate power, achieving system stability and power balance.

[0107] Step 3: Based on the simulation experiment function and multi-mode design, a multi-mode flexible switching coordinated control strategy and experimental steps and methods are proposed. The original method is optimized and simulated and verified on the MATLAB platform.

[0108] In this simulation system, the grid-connected inverter control strategy adopts voltage and current double closed-loop control to control the DC bus U dc The photovoltaic power generation control strategy uses maximum power point tracking technology to track the maximum power point by comparing the instantaneous conductance of the photovoltaic power generation with the change in conductance, ensuring maximum utilization of the photovoltaic power generation power. Fuel cell control includes power control and current control. Hydrogen fuel cells are based on the fuel cell characteristic curve. By changing the output current of the fuel cell stack, the fuel cell stack port voltage and output power can be adjusted. The electrolyzer control strategy is divided into rectification control and power control. When the power supply is sufficient or there is surplus, the excess power is supplied to the electrolyzer equipment, increasing hydrogen production and improving energy utilization. When the power supply is tight or even insufficient, the electrolyzer equipment will reduce hydrogen production or suspend operation. Its control strategy is similar to that of hydrogen fuel cells, both of which are power control.

[0109] In order to further illustrate the reliability of the present invention, the following specific experimental steps are proposed and optimized on the original basis:

[0110] First, a specific simulation model was built based on the mathematical model to ensure that all modules functioned properly during actual operation. On this basis, the system's capacity configuration was parameterized, effectively providing a new power system simulation model based on solar-hydrogen complementarity.

[0111] The system then determines the system's current mode based on the real-time power measurements of each module and sends control signals to each module. In grid-connected mode, the PV modules utilize MPPT control based on control instructions from the upper-level system to achieve maximum power output. To ensure stable operation of the DC bus during operation, the inverter controller implements PI control based on the bus voltage setpoint and real-time measurements. The fuel cell and electrolyzer modules use the upper-level real-time control instructions as a reference for power output.

[0112] Taking into account signal delay and equipment startup, the simulation experiment optimized the power control signal of the fuel cell equipment and electrolyzer equipment on the original basis. The power prediction value P(t+1) comprehensively considers the weighted signals of each module at the previous N+1 moments, among which the predicted value of the fuel cell power at time t+1 P fc (t+1) is:

[0113]

[0114] Where, P is the dynamic adjustment coefficient of the power signal of the power grid at time ti; grid (ti) is the grid power at time ti; P is the dynamic adjustment coefficient of the load power signal at time ti; grid (ti) is the load power at time ti; is the dynamic adjustment coefficient of the photovoltaic power signal at time ti; P pv (ti) is the photovoltaic power at time ti.

[0115] The predicted value P of the electrolytic cell power at time t+1 ele (t+1) is:

[0116]

[0117] To improve the utilization efficiency of hydrogen fuel cells and electrolyzers, two sets of equipment with different power ratings are prepared. These are divided into two tiers based on power demand: tier one and tier two. In tier one, the fuel cell's rated power is 20kW, and the electrolyzer's rated power is 20kW; in tier two, the fuel cell's rated power is 50kW, and the electrolyzer's rated power is 50kW. In multi-mode operation, tier one equipment is activated if the fuel cell's output power and the electrolyzer's power consumption are within 30kW; tier two equipment is activated if the fuel cell's output power and the electrolyzer's power consumption exceed 30kW.

[0118] Based on the law of conservation of energy, ignoring losses caused by energy conversion and transmission, the hydrogen fuel cell and electrolyzer quickly track the flexible regulation needs of the photovoltaic grid-connected system under different modes. Simulations conducted on the MATLAB platform have verified that this multi-mode flexible switching solar-hydrogen complementary simulation method and system can accurately respond to power regulation requirements under different modes, achieving multi-energy complementarity and coordinated operation.

[0119] The specific embodiments described above make the technical solutions and advantageous effects of the present invention more detailed and clear. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and claims of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A multi-mode flexible switching light-hydrogen complementary simulation experimental method, characterized by: The specific implementation steps are as follows: Step 1: Design system capacity configuration and establish a series of mathematical models including photovoltaic power generation mathematical model, hydrogen fuel cell mathematical model, electrolyzer mathematical model, etc. Step 2: Based on the capacity configuration design, design a multi-mode simulation experiment function while fully considering the operational goals of efficient energy utilization, suppressing power fluctuations, and achieving flexible grid dispatch; Step 3: Based on the simulation experiment function and multi-mode design, a multi-mode flexible switching collaborative control strategy and experimental steps and methods are proposed, optimized based on the original method, and simulated and verified based on the MATLAB platform; The step 3 specifically includes: Taking into account the signal delay and equipment startup, the simulation experiment optimized the power control signal of the fuel cell equipment and electrolyzer equipment on the original basis. The power prediction value P(t+1) comprehensively considers the weighted signals of each module at the previous N+1 moments, among which the predicted value of the fuel cell power at time t+1 P fc (t+1) is: Where, P is the dynamic adjustment coefficient of the power signal of the power grid at time ti; grid (ti) is the grid power at time ti; P is the dynamic adjustment coefficient of the load power signal at time ti; grid (ti) is the load power at time ti; is the dynamic adjustment coefficient of the photovoltaic power signal at time ti; P pv (ti) is the photovoltaic power at time ti; The predicted value P of the electrolytic cell power at time t+1 ele (t+1) is: At the same time, in order to improve the utilization efficiency of hydrogen fuel cells and electrolyzer equipment, two groups of equipment with different rated powers are prepared. They are divided into two gears based on power demand, namely gear one and gear two. In gear one, the rated power of the fuel cell is 20kW and the rated power of the electrolyzer is 20kW; in gear two, the rated power of the fuel cell is 50kW and the rated power of the electrolyzer is 50Kw. In multi-mode, if the output power of the fuel cell and the power consumption of the electrolyzer are within 30kW, the gear one equipment is started; if the output power of the fuel cell and the power consumption of the electrolyzer exceed 30kW, the gear two equipment is started.

2. The multi-mode flexible switching solar-hydrogen complementary simulation experimental method according to claim 1 is characterized in that: The step 1 specifically includes: Fuel simulation cell capacity configuration: Total capacity ≥ 50kW, fuel cells are divided into two groups: The first group of fuel cells consists of 300 cell stacks, with a single cell stack voltage of 1.2041V, a rated current of 100A, a rated voltage of 500V, a rated power of 50kW, a rated hydrogen supply pressure of 1.5bar, a rated oxygen supply pressure of 1bar, and a maximum output voltage of 600V; the second group of fuel cells consists of 70 cell stacks, with a single cell stack voltage of 1.2113V, a rated current of 40A, a rated voltage of 500V, a rated power of 20kW, a rated hydrogen supply pressure of 1.5bar, a rated oxygen supply pressure of 1bar, and a maximum output voltage of 600V; Photovoltaic simulation power supply capacity configuration: total capacity ≥ 50kW, consisting of 17 photovoltaic modules connected in series and parallel. A single photovoltaic module string is formed by 14 photovoltaic arrays connected in series. The short-circuit current of a single photovoltaic array is 7.84A, the rated current is 125A, the rated voltage is 400V, and the maximum output voltage is 508.2V. Electrolytic cell simulation capacity configuration: total capacity ≥ 50kW, the electrolytic cells are divided into two groups: the first group consists of 200 electrolytic cells, with a single cell reversible voltage of 1.23V, an electrode area of ​​0.1㎡, a rated current of 125A, and a rated voltage of 400V; the second group consists of 100 electrolytic cells, with a single cell reversible voltage of 1.23V, an electrode area of ​​0.1㎡, a rated current of 50A, and a rated voltage of 400V; PV inverter parameters: grid-connected rated voltage 800V, grid-side frequency 50Hz, THD ≤ 5%, AC voltage 380VAC, MPPT voltage range 200-950V, power factor 1; Fuel cell inverter parameters: grid-connected rated voltage 800V, grid-side frequency 50Hz, THD ≤ 5%, AC voltage 380VAC, power factor 1; Electrolyzer converter parameters: DC rated voltage 800VDC, grid-side frequency 50Hz, THD ≤ 5%, AC voltage 380VAC, power factor 1; (1) Mathematical model of photovoltaic power generation: I=I pv -I d Where, I pv is the current generated by the photovoltaic cell due to solar radiation; I0 is the saturation current; I is the load current; V is the photovoltaic output voltage; R S is the series impedance of the photovoltaic cell; α is the time factor; (2) Hydrogen fuel cell mathematical model: IN fc =U oc -IN ohm -IN act U ohm =R ohm ·i fc Where U fc is the fuel cell output voltage; U oc is the open circuit voltage of the fuel cell, U ohm is the ohmic overvoltage loss, U act is the absolute polarization voltage loss; K c is the voltage constant under nominal working conditions; E0 is the electromotive force under standard pressure; T f is the operating temperature of the fuel cell; z is the number of moving electrons; F is the Faraday constant; R is the gas constant; is the hydrogen partial pressure in the pile; is the partial pressure of oxygen in the pile; is the partial pressure of water vapor in the pile; R ohm is the equivalent internal resistance; i fc is the fuel cell current; N fc is the number of fuel cells; A is the Tafel slope; i0 is the exchange current; T fc is the response time; (3) Electrolytic cell mathematical model: Where U el is the working voltage of a single electrolytic cell; U r is the reversible voltage; A el is the electrode area; T el is temperature; I el is the current; r1 and r2 are the ohmic resistance parameters; s and k T1 、k T2 、k T3 is the overvoltage coefficient; is the hydrogen production rate; η e is the electrolytic cell efficiency; N e is the number of electrolytic cells; F is the Faraday constant; P e is the power consumed; (4) Boost converter mathematical model: Where: i1 is the inductor current; V out1 is the output voltage; V in1 is the input voltage and D1 is the control signal; (5) Buck converter mathematical model: Where: i2 is the inductor current; V in2 is the input voltage; V out2 is the output voltage and d is the control signal.

3. The multi-mode flexible switching solar-hydrogen complementary simulation experimental method according to claim 1 is characterized in that: The step 2 specifically includes: Set P PV is the output power of photovoltaic power generation, P load is the load demand power, P s =P PV -P load is the remaining power, P grid is the power demanded by the grid, P fc is the output power of fuel cell power generation, P ele Power consumption for the electrolytic cell; Mode 1: P s ≥0, P grid >0, P grid ≥P s , at this time P fc =P grid -P s , P ele =0, when photovoltaic power generation can meet the load demand but cannot meet the grid demand, the fuel cell will provide the required energy as a backup power source and the electrolysis cell will stop operating; Mode 2: P s ≥0, P grid >0, P grid <P s , at this time P fc =0,P ele =P s -P grid ,When PV power generation can meet both the load demand and the grid demand, the fuel cell stops operating and the remaining energy is used to produce hydrogen in the electrolysis cell; Mode 3: P s ≥0, P grid =0, at this time P fc =0,P ele =P s ,When PV power generation meets the load demand and there is no grid demand, the fuel cell stops operating and the remaining energy is used to produce hydrogen in the electrolysis cell; Mode 4: P s ≥0, P grid <0, at this time P fc =0,P ele =P s +|P grid When photovoltaic power generation meets the load demand and the grid has excess power, the fuel cell stops running and the remaining energy is used to produce hydrogen in the electrolysis cell. Mode 5: P s <0, P grid >0, then P fc =P grid +|P s |,P ele =0, when photovoltaic power generation cannot meet the load demand and grid demand, the fuel cell will provide the required energy as a backup power source and the electrolysis cell will stop operating; Mode 6: P s <0, P grid =0, at this time P fc =|P s |,P ele =0, when photovoltaic power generation can meet the load demand and there is no grid demand, the fuel cell will provide the required energy as a backup power source and the electrolysis cell will stop operating; Mode 7: P s <0, P grid <0,|P grid |≥|P s |, at this time P fc =0,P ele =|P grid |-|P s |,When photovoltaic power generation cannot meet the load demand and there is excess grid power in the system, the fuel cell stops running when the two work together to meet the load demand, and the remaining energy is used to produce hydrogen in the electrolysis cell; Mode 8: P s <0, P grid <0,|P grid |<|P s |, at this time P fc =|P s |-|P grid |,P ele =0, when photovoltaic power generation cannot meet the load demand and there is excess power in the grid, and the combined effect of the two still cannot meet the load demand, the fuel cell will provide the required energy as a backup power source and the electrolytic cell will stop operating.

4. A multi-mode flexible switching solar-hydrogen complementary simulation system according to any one of claims 1 to 3, characterized in that: include: Photovoltaic power generation module, load module, hydrogen energy module; The hydrogen energy module includes a hydrogen fuel cell power generation module and an electrolysis hydrogen production module.

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