Water electrolysis hydrogen production system based on photovoltaic power generation

Abstract

The invention provides a photovoltaic power generation-based water electrolysis hydrogen production system. The photovoltaic power generation-based water electrolysis hydrogen production system comprises an energy management device, an energy storage device, a photovoltaic array device and a water electrolysis hydrogen production device, the photovoltaic array device is connected with the energy storage device and the water electrolysis hydrogen production device, the energy storage device is connected with the water electrolysis hydrogen production device, and the water electrolysis hydrogen production device and the energy storage device are further connected with an external power grid; the energy management device is connected with the control end of the photovoltaic array device, the second control end of the energy management device is connected with the control end of the energy storage device, and the third control end of the energy management device is connected with an external power grid; the energy management device controls power supply of the photovoltaic array device, the energy storage device and the external power grid to the water electrolysis hydrogen production device and controls power supply of the photovoltaic array device and the external power grid to the energy storage device. The photovoltaic array device is directly coupled with the water electrolysis hydrogen production device, equipment loss and cost are reduced, an energy storage system and an external power grid are matched, and the defects of intermittency, randomness and the like of photovoltaic power generation are effectively overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power generation, and in particular to a water electrolysis hydrogen production system based on photovoltaic power generation. Background Art

[0002] With the development of human society and economy, the energy and environmental crises caused by the use of fossil energy are becoming increasingly severe. The development and utilization of green and renewable energy is an important strategy for the sustainable development of human society. Among them, clean and abundant solar energy is the most important renewable energy for mankind. People are constantly exploring the conversion and utilization of solar energy through technologies such as photothermal, photovoltaic, and photocatalytic. Due to the limitations of thermal energy and electrical energy in storage and mobility, the conversion of solar energy into high-energy-density hydrogen based on photo / electrocatalytic hydrolysis technology has good application prospects.

[0003] Due to the volatility and intermittent nature of photovoltaic power generation, as well as the continuous production characteristics of water electrolysis hydrogen production devices, a certain capacity of energy storage system must be equipped to regulate photovoltaic power generation. Photovoltaic power generation needs to be collected and stored when available until it is needed. According to the capacity configuration relationship between photovoltaic power generation and water electrolysis hydrogen production devices, the capacity ratio is usually 1:0.8. During the noon period, when photovoltaic power generation reaches its peak, its capacity should be greater than the maximum demand for water electrolysis hydrogen production, and the energy storage system is in a state of charging and collecting electricity; in the morning, evening or night, the solar radiation capacity decreases, and the photovoltaic power generation capacity is lower than the maximum demand for water electrolysis hydrogen production. At this time, the energy storage system can discharge the electricity stored during the peak period, which can achieve load balancing and peak regulation, and improve the system's ability to operate continuously and reliability.

[0004] In the domestic photovoltaic power generation system supporting water electrolysis hydrogen production system, water electrolysis hydrogen production has a relatively mature production process, the conversion efficiency of alkaline electrolysis system is 70%-80%, and the conversion efficiency of PEM electrolysis system is 70%-90%. The traditional photovoltaic system supporting water electrolysis hydrogen production system converts solar energy into electrical energy, and converts it into 400V AC through DC / AC inverter or boosts it to 10kV, 35kV voltage level to power the water electrolysis hydrogen production device. The water electrolysis hydrogen production device supplies power to the electrolyzer through a step-down transformer and a rectifier transformer.

[0005] The conversion efficiency of renewable energy to hydrogen energy is low, and one of the important reasons is that there are many intermediate conversion links. In the scheme of electrolysis hydrogen production after photovoltaic power generation is boosted, the DC power generated by the photovoltaic panel is converted into AC power through an inverter, and then converted into DC power for electrolysis hydrogen production through a step-up transformer and a rectifier transformer. During this process, a relatively high energy loss will occur. The MPPT (Maximum Power Point Tracking) controller and DC-DC converter scheme for photovoltaic direct coupling hydrogen production enable the photovoltaic panel to operate at the maximum power point. There are still many intermediate links, which will still cause certain energy consumption. In addition, the energy storage system is not considered, and the intermittent and random characteristics of photovoltaic power generation cannot be effectively solved. It is impossible to store and utilize the remaining photovoltaic power during the peak period of noon. At the same time, on cloudy days or at night, the water electrolysis hydrogen production device cannot work continuously, and the hydrogen production device cannot be operated continuously, and the output and efficiency of the water electrolysis hydrogen production device cannot be guaranteed. Summary of the invention

[0006] Based on this, it is necessary to provide a water electrolysis hydrogen production system based on photovoltaic power generation to address the above technical problems.

[0007] A water electrolysis hydrogen production system based on photovoltaic power generation, comprising: an energy management device, an energy storage device, a photovoltaic array device and a water electrolysis hydrogen production device;

[0008] The output end of the photovoltaic array device is connected to the input end of the energy storage device and the water electrolysis hydrogen production device, the output end of the energy storage device is connected to the water electrolysis hydrogen production device, the water electrolysis hydrogen production device is also used to connect to an external power grid, and the input end of the energy storage device is also used to connect to the external power grid;

[0009] The first control end of the energy management device is connected to the control end of the photovoltaic array device, the second control end of the energy management device is connected to the control end of the energy storage device, and the third control end of the energy management device is used to connect to an external power grid;

[0010] The energy management device is used to control the power supply of the photovoltaic array device, the energy storage device, and the external power grid to the water electrolysis hydrogen production device, and is also used to control the power supply of the photovoltaic array device and the external power grid to the energy storage device.

[0011] In one embodiment, the energy management device is used to obtain the load of the water electrolysis hydrogen production device and the first capacity of the photovoltaic array device, compare the load of the water electrolysis hydrogen production device and the first capacity, and control the power supply of the photovoltaic array device, the energy storage device, and the external power grid to the water electrolysis hydrogen production device according to the comparison result of the load of the water electrolysis hydrogen production device and the first capacity, and control the power supply of the photovoltaic array device and the external power grid to the energy storage device.

[0012] In one embodiment, the energy management device is used to:

[0013] When the first capacity is greater than the load of the water electrolysis hydrogen production device, controlling the photovoltaic array device to supply power to the energy storage device and the water electrolysis hydrogen production device, wherein the energy storage device is in a charging state;

[0014] When the first capacity is less than or equal to the load of the water electrolysis hydrogen production device, the sum of the first capacity and the second capacity of the energy storage device is compared with the load of the water electrolysis hydrogen production device, and based on the comparison result of the sum of the first capacity and the second capacity with the load of the water electrolysis hydrogen production device, the photovoltaic array device, the energy storage device, and the external power grid are controlled to supply power to the water electrolysis hydrogen production device, and the photovoltaic array device and the external power grid are controlled to supply power to the energy storage device.

[0015] In one embodiment, the energy management device is used to:

[0016] When the first capacity is less than or equal to the load of the water electrolysis hydrogen production device, and when the sum of the first capacity and the second capacity is greater than the load of the water electrolysis hydrogen production device, controlling the photovoltaic array device and the energy storage device to simultaneously supply power to the water electrolysis hydrogen production device, wherein the energy storage device is in a discharge state;

[0017] When the first capacity is less than or equal to the load of the water electrolysis hydrogen production device, and when the sum of the first capacity and the second capacity is less than or equal to the load of the water electrolysis hydrogen production device, the external power grid is controlled to supply power to the energy storage device and the water electrolysis hydrogen production device, wherein the energy storage device is in a charging state.

[0018] In one embodiment, the water electrolysis hydrogen production device is used for:

[0019] When the first capacity is greater than the load of the water electrolysis hydrogen production device, the water electrolysis hydrogen production load rate is controlled to be 90% to 100%.

[0020] In one embodiment, the water electrolysis hydrogen production device is used for:

[0021] When the first capacity is less than or equal to the load of the water electrolysis hydrogen production device, and when the sum of the first capacity and the second capacity is greater than the load of the water electrolysis hydrogen production device, the water electrolysis hydrogen production load rate is controlled to be 80% to 100%.

[0022] In one embodiment, the water electrolysis hydrogen production device is used for:

[0023] When the first capacity is less than or equal to the load of the water electrolysis hydrogen production device, and when the sum of the first capacity and the second capacity is less than or equal to the load of the water electrolysis hydrogen production device, the water electrolysis hydrogen production load rate is controlled to be less than 40%.

[0024] In one of the embodiments, a filter is further included, and the output end of the photovoltaic array device is connected to the input end of the energy storage device and the water electrolysis hydrogen production device through the filter.

[0025] In one embodiment, a rectifier is further included, wherein the input end of the rectifier is used to connect to the external power grid, the first output end of the rectifier is connected to the water electrolysis hydrogen production device, and the second output end of the rectifier is connected to the input end of the energy storage device.

[0026] In one of the embodiments, it also includes an external power grid switch unit, the input end of the external power grid switch unit is used to connect to the external power grid, the output end of the external power grid switch unit is respectively connected to the input end of the energy storage device and the water electrolysis hydrogen production device, and the control end of the external power grid switch unit is connected to the third control end of the energy management device.

[0027] In the above-mentioned water electrolysis hydrogen production system based on photovoltaic power generation, the photovoltaic array device is directly coupled with the water electrolysis hydrogen production device, and the intermediate process between the photovoltaic array device and the water electrolysis hydrogen production device is optimized to reduce equipment loss and cost, and achieve the purpose of energy saving and consumption reduction, with significant economic and social benefits. At the same time, the supporting energy storage system and the external power grid can make up for the power supply to the water electrolysis hydrogen production device when the light energy is insufficient, effectively solving the shortcomings of intermittent and random photovoltaic power generation, making full use of the energy storage device to store the remaining photovoltaic power during the peak period of noon, and effectively using the difference in peak and valley electricity prices of the power grid to ensure the stability of the power input of the water electrolysis hydrogen production device and improve the output and efficiency of the water electrolysis hydrogen production device. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A system logic block diagram of a water electrolysis hydrogen production system based on photovoltaic power generation in one embodiment;

[0029] Figure 2 Schematic diagram of the relationship between the operating conditions of an energy management device and solar irradiance in one embodiment. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0031] Embodiment 1

[0032] In this embodiment, Figure 1 As shown, a water electrolysis hydrogen production system based on photovoltaic power generation is provided, which includes: an energy management device 110, an energy storage device 140, a photovoltaic array device 120 and a water electrolysis hydrogen production device 130; the output end of the photovoltaic array device 120 is connected to the input end of the energy storage device 140 and the water electrolysis hydrogen production device 130, the output end of the energy storage device 140 is connected to the water electrolysis hydrogen production device 130, the water electrolysis hydrogen production device 130 is also used to connect to an external power grid, and the input end of the energy storage device 140 is also used to connect to the external power grid; the energy management device 110 includes an energy management device 110, an energy storage device 140, a photovoltaic array device 120, and a water electrolysis hydrogen production device 130; the output end of the photovoltaic array device 120 is connected to the input end of the energy storage device 140 and the water electrolysis hydrogen production device 130, the output end of the energy storage device 140 is connected to the water electrolysis hydrogen production device 130, the water electrolysis hydrogen production device 130 is also used to connect to an external power grid, and the input end of the energy storage device 140 is also used to connect to the external power grid; The first control end of the energy management device 110 is connected to the control end of the photovoltaic array device 120, the second control end of the energy management device 110 is connected to the control end of the energy storage device 140, and the third control end of the energy management device 110 is used to connect to the external power grid; the energy management device 110 is used to control the power supply of the photovoltaic array device 120, the energy storage device 140, and the external power grid to the water electrolysis hydrogen production device 130, and is also used to control the power supply of the photovoltaic array device 120 and the external power grid to the energy storage device 140.

[0033] In this embodiment, the energy storage device 140 includes multiple battery packs. The energy storage device 140 can operate in a charging mode or a discharging mode. When the working state of the energy storage device 140 is the charging mode, the energy storage device 140 is charged by the external power grid or the photovoltaic array device 120. When the working state of the energy storage device 140 is the discharging mode, the energy storage device 140 supplies power to the water electrolysis hydrogen production device 130.

[0034] The photovoltaic array device 120 includes a plurality of photovoltaic cell assemblies, which are connected in series or in parallel. The photovoltaic cell assemblies are used to convert solar radiation energy into electrical energy to supply power to the energy storage device 140 and the water electrolysis hydrogen production device 130 .

[0035] In one embodiment, the water electrolysis hydrogen production device 130 includes a step-down transformer, a rectifier transformer and an electrolyzer, the electrolyzer includes a tank body and electrodes, the electrodes are connected to the step-down transformer and the rectifier transformer, the electrodes are connected to the photovoltaic array device 120, the energy storage device 140 and the external power grid through the step-down transformer and the rectifier transformer, the electrolyzer is filled with water, the electrodes are arranged in the electrolyzer, and the electrodes are used to electrolyze the water in the electrolyzer to generate hydrogen after power is turned on. In this embodiment, the electrolyzer uses electrical energy to electrolyze water to generate hydrogen, and this example uses an electrolyzer with a hydrogen production capacity of 1000Nm3 / h.

[0036] The energy management device 110 is used to control the power supply of the energy storage device 140, the photovoltaic array device 120 and the external power grid. The energy management device 110 dynamically adjusts the power output according to the power supply of the photovoltaic array device 120, the energy storage device 140, the external power grid and the power demand of the electrolyzer to achieve stable and reliable power input to the electrolyzer.

[0037] In the above embodiment, the photovoltaic array device 120 is directly coupled with the water electrolysis hydrogen production device 130, and the intermediate process between the photovoltaic array device 120 and the water electrolysis hydrogen production device 130 is optimized to reduce equipment loss and cost, achieve the purpose of energy saving and consumption reduction, and have significant economic and social benefits. At the same time, the supporting energy storage system and the external power grid can make up for the power supply to the water electrolysis hydrogen production device 130 when the light energy is insufficient, effectively solve the shortcomings of intermittent and random photovoltaic power generation, make full use of the energy storage device 140 to store the remaining photovoltaic power during the peak period of noon, effectively use the difference in peak and valley electricity prices of the power grid, and achieve stable power input of the water electrolysis hydrogen production device 130, thereby improving the output and efficiency of the water electrolysis hydrogen production device 130. Thereby effectively improving the output of water electrolysis hydrogen production, improving the utilization rate of the photovoltaic power generation system, further reducing equipment loss and manufacturing costs, and solving the shortcomings of intermittent and random photovoltaic power generation.

[0038] In one embodiment, the energy management device 110 is used to obtain the load of the water electrolysis hydrogen production device 130 and the first capacity of the photovoltaic array device 120, compare the load of the water electrolysis hydrogen production device 130 with the first capacity, and control the power supply of the photovoltaic array device 120, the energy storage device 140, and the external power grid to the water electrolysis hydrogen production device 130 according to the comparison result of the load of the water electrolysis hydrogen production device 130 and the first capacity, and control the power supply of the photovoltaic array device 120 and the external power grid to the energy storage device 140.

[0039] In this embodiment, the load of the water electrolysis hydrogen production device 130 is the load demand of the water electrolysis hydrogen production device 130, also known as the capacity of the water electrolysis hydrogen production device 130, the first capacity of the photovoltaic array device 120 is the instantaneous power generation of the photovoltaic array device 120, the load of the water electrolysis hydrogen production device 130 is S4, and the first capacity of the photovoltaic array device 120 is S1. The load S4 of the water electrolysis hydrogen production device 130 is compared with the first capacity S1 of the photovoltaic array device 120, and the energy management device 110 controls the photovoltaic array device 120, the energy storage device 140, and the external power grid to supply power to the water electrolysis hydrogen production device 130 according to the comparison result of S4 and S1, and also controls the energy storage device 140 to switch to the discharge mode or the charging mode according to the comparison result. In this way, when the first capacity of the photovoltaic array device 120 cannot meet the load demand of the water electrolysis hydrogen production device 130, the energy management device 110 can control the energy storage device 140 to discharge or introduce an external power grid to power the water electrolysis hydrogen production device 130, which can make up for the power supply to the water electrolysis hydrogen production device 130 when the light energy is insufficient. When the first capacity of the photovoltaic array device 120 is large, it is easy to cause waste of power generation of the photovoltaic array device 120. In this way, the energy storage device 140 is controlled to charge, and the photovoltaic array device 120 charges the energy storage device 140 to avoid waste of power from the photovoltaic array device 120. In this way, the shortcomings of intermittent and random photovoltaic power generation are effectively solved, the energy storage device 140 is fully utilized to store the remaining photovoltaic power during the lunch peak period, and the peak-valley electricity price difference of the power grid is effectively utilized to ensure stable power input of the water electrolysis hydrogen production device 130, thereby improving the output and efficiency of the water electrolysis hydrogen production device 130.

[0040] In one embodiment, the energy management device 110 is used to: when the first capacity is greater than the load of the water electrolysis hydrogen production device 130, control the photovoltaic array device 120 to supply power to the energy storage device 140 and the water electrolysis hydrogen production device 130, wherein the energy storage device 140 is in a charging state; when the first capacity is less than or equal to the load of the water electrolysis hydrogen production device 130, compare the sum of the first capacity and the second capacity of the energy storage device 140 with the load of the water electrolysis hydrogen production device 130, and according to the The comparison result of the sum of the first capacity and the second capacity and the load of the water electrolysis hydrogen production device 130 controls the power supply of the photovoltaic array device 120, the energy storage device 140, and the external power grid to the water electrolysis hydrogen production device 130, and controls the power supply of the photovoltaic array device 120 and the external power grid to the energy storage device 140. In one embodiment, the water electrolysis hydrogen production device 130 is used to: when the first capacity is greater than the load of the water electrolysis hydrogen production device 130, control the water electrolysis hydrogen production load rate to 90% to 100%.

[0041] In this embodiment, when the first capacity S1 is greater than the load S4 of the water electrolysis hydrogen production device 130, it indicates that the power generation of the photovoltaic array device 120 can meet the load demand of the water electrolysis hydrogen production device 130. Therefore, only the photovoltaic array device 120 is used to power the water electrolysis hydrogen production device 130, and the excess electric energy of the photovoltaic array device 120 is stored in the energy storage device 140. At this time, the energy storage device 140 is in charging mode, which can effectively improve the utilization rate of electric energy. In this embodiment, when the first capacity S1 is greater than the load S4 of the water electrolysis hydrogen production device 130, the water electrolysis hydrogen production load rate of the water electrolysis hydrogen production device 130 is 90% to 100%.

[0042] When the first capacity S1 is less than or equal to the load S4 of the water electrolysis hydrogen production device 130, it indicates that the power generation of the photovoltaic array device 120 cannot meet the load demand of the water electrolysis hydrogen production device 130. Therefore, the energy storage device 140 and the external power grid are controlled to supply power to the water electrolysis hydrogen production device 130 to improve the output and efficiency of the water electrolysis hydrogen production device 130.

[0043] In one embodiment, the energy management device 110 is used to: when the first capacity is less than or equal to the load of the water electrolysis hydrogen production device 130, and when the sum of the first capacity and the second capacity is greater than the load of the water electrolysis hydrogen production device 130, control the photovoltaic array device 120 and the energy storage device 140 to simultaneously supply power to the water electrolysis hydrogen production device 130, wherein the energy storage device 140 is in a discharging state; when the first capacity is less than or equal to the load of the water electrolysis hydrogen production device 130, and when the sum of the first capacity and the second capacity is less than or equal to the load of the water electrolysis hydrogen production device 130, control the external power grid to supply power to the energy storage device 140 and the water electrolysis hydrogen production device 130, wherein the energy storage device 140 is in a charging state. In this embodiment, the electrolytic water hydrogen production device 130 is used to control the electrolytic water hydrogen production load rate to be 80% to 100% when the first capacity is less than or equal to the load of the electrolytic water hydrogen production device 130, and when the sum of the first capacity and the second capacity is greater than the load of the electrolytic water hydrogen production device 130. The electrolytic water hydrogen production device 130 is used to control the electrolytic water hydrogen production load rate to be less than 40% when the first capacity is less than or equal to the load of the electrolytic water hydrogen production device 130, and when the sum of the first capacity and the second capacity is less than or equal to the load of the electrolytic water hydrogen production device 130.

[0044] In this embodiment, when the first capacity S1 is less than or equal to the load S4 of the water electrolysis hydrogen production device 130, and when the sum of the first capacity S1 and the second capacity S2 is greater than the load S4 of the water electrolysis hydrogen production device 130, it indicates that the power generation of the photovoltaic array device 120 cannot meet the load demand of the water electrolysis hydrogen production device 130, but the discharge of the energy storage device 140 can make up for the insufficient power generation of the photovoltaic array device 120, so the energy storage device 140 switches to the discharge mode, and the photovoltaic array device 120 and the energy storage device 140 simultaneously supply power to the water electrolysis hydrogen production device 130. At this time, the water electrolysis hydrogen production load rate of the water electrolysis hydrogen production device 130 is 80% to 100%.

[0045] When the first capacity S1 is less than or equal to the load S4 of the water electrolysis hydrogen production device 130, and when the sum of the first capacity S1 and the second capacity S2 is less than or equal to the load S4 of the water electrolysis hydrogen production device 130, it indicates that the sum of the power generation of the photovoltaic array device 120 and the discharge of the energy storage device 140 cannot meet the load demand of the water electrolysis hydrogen production device 130, and therefore, it is necessary to introduce electric energy from the external power grid. Therefore, the external power grid is introduced to power the water electrolysis hydrogen production device 130, and at the same time, the energy storage device 140 switches to the charging mode, and the external power grid simultaneously powers the water electrolysis hydrogen production device 130 and the energy storage device 140, and the energy storage device 140 is powered until the energy storage device 140 is charged to the preset power threshold. At this time, the water electrolysis hydrogen production load rate of the water electrolysis hydrogen production device 130 is less than 40%. It should be understood that after the introduction of power supply from the external power grid, the photovoltaic array device 120 can continue to supply power to the water electrolysis hydrogen production device 130 , or stop supplying power to the water electrolysis hydrogen production device 130 and store the electrical energy in the energy storage device 140 .

[0046] In one embodiment, the water electrolysis hydrogen production system based on photovoltaic power generation further includes a filter 210 , and the output end of the photovoltaic array device 120 is connected to the input end of the energy storage device 140 and the water electrolysis hydrogen production device 130 through the filter 210 .

[0047] In this embodiment, the filter 210 is used to filter the direct current output by the photovoltaic array device 120 to make the direct current output by the photovoltaic array device 120 more stable.

[0048] In one embodiment, the water electrolysis hydrogen production system based on photovoltaic power generation also includes a rectifier 220, the input end of the rectifier 220 is used to connect to the external power grid, the first output end of the rectifier 220 is connected to the water electrolysis hydrogen production device 130, and the second output end of the rectifier 220 is connected to the input end of the energy storage device 140.

[0049] In this embodiment, the rectifier 220 is an AC-DC (alternating current-direct current) rectifier 220, which is used to convert the alternating current input of the external power grid into direct current to provide direct current to the water electrolysis hydrogen production device 130 and the energy storage device 140.

[0050] In order to achieve control over the power supply of the external power grid, in one embodiment, the water electrolysis hydrogen production system based on photovoltaic power generation also includes an external power grid switch unit 230, the input end of the external power grid switch unit 230 is used to connect to the external power grid, the output end of the external power grid switch unit 230 is respectively connected to the input end of the energy storage device 140 and the water electrolysis hydrogen production device 130, and the control end of the external power grid switch unit 230 is connected to the third control end of the energy management device 110.

[0051] In this embodiment, the external grid switch unit 230 serves as a switch for accessing the external grid, and controls the power supply of the external grid to the water electrolysis hydrogen production system based on photovoltaic power generation. The energy management device 110 inputs a control signal to the control end of the external grid switch unit 230 through the third control end to control the on and off of the external grid switch unit 230. When the control end of the external grid switch unit 230 receives the on signal of the energy management device 110, the external grid switch unit 230 is turned on, so that the external grid can supply power to the energy storage device 140 and the water electrolysis hydrogen production device 130. When the control end of the external grid switch unit 230 receives the off signal of the energy management device 110, the external grid switch unit 230 is turned off, so that the connection between the external grid and the water electrolysis hydrogen production system based on photovoltaic power generation is disconnected, so as to prevent the external grid from supplying power to the energy storage device 140 and the water electrolysis hydrogen production device 130. In one embodiment, the first output end of the external power grid switch unit 230 is connected to the input end of the energy storage device 140, and the second output end of the external power grid switch unit 230 is connected to the water electrolysis hydrogen production device 130. In this way, the energy management device 110 can control the external power grid to supply power to the energy storage device 140 or the water electrolysis hydrogen production device 130 by controlling the conduction or disconnection of the first output end and the second output end. In one embodiment, the output end of the external power grid switch unit 230 is connected to the input end of the rectifier 220, the first output end of the rectifier 220 is connected to the water electrolysis hydrogen production device 130, the second output end of the rectifier 220 is connected to the input end of the energy storage device 140, and the energy management device 110 is connected to the control end of the rectifier 220. In this way, the energy management device 110 can control the external power grid to supply power to the energy storage device 140 or the water electrolysis hydrogen production device 130 by controlling the conduction or disconnection of the first output end and the second output end of the rectifier 220.

[0052] Embodiment 2

[0053] In this embodiment, the water electrolysis hydrogen production system based on photovoltaic power generation includes: a photovoltaic array device 120, a filter 210, an external power grid, an AC-DC rectifier 220, an energy storage device 140, an energy management device 110 and an electrolyzer.

[0054] Photovoltaic array device 120: converts solar radiation energy into electrical energy, and is composed of photovoltaic cell components with reasonable series / parallel design.

[0055] The filter 210 is a device for improving the power quality of the DC power output by the photovoltaic array device 120 .

[0056] AC-DC rectifier 220: a device that converts the AC power input from the external power grid into DC power.

[0057] Energy storage device 140: A photovoltaic energy storage device 140 provided for the purpose of power peak regulation, and used to store surplus electric energy.

[0058] Energy management device 110: The energy management device 110 dynamically adjusts the power output according to the photovoltaic array device 120, the energy storage device 140, the external power grid power supply and the power demand of the electrolyzer to achieve stable and reliable power input to the electrolyzer.

[0059] Electrolyzer: A device that converts electrical energy into water electrolysis to produce hydrogen. This example uses an electrolyzer with a hydrogen production capacity of 1000Nm3 / h.

[0060] In this embodiment, the working process and principle of the water electrolysis hydrogen production system based on photovoltaic power generation are as follows:

[0061] The energy conversion rate of photovoltaic power generation device and water electrolysis hydrogen production under direct coupling connection is used. Ideally, the IV working characteristic curve of the electrolyzer is as close as possible to the maximum power point of the photovoltaic array under different degrees of solar irradiance. The reasonable number of series / parallel groups of the photovoltaic array is calculated. The relationship curve between the working condition of the energy management device and the solar irradiance is as follows: Figure 2 shown.

[0062] Working logic of the energy management device 110: Assume that the capacity (instantaneous power generation) of the photovoltaic array device 120 is S1, the capacity of the energy storage device 140 is S2, the capacity of the external power grid is S3 (usually regarded as a stable infinite capacity), and the capacity of the water electrolysis hydrogen production device 130 is S4. The working state of each unit is adjusted by the load rate of the water electrolysis hydrogen production device 130, and the working logic of the energy management device 110 is as follows to achieve a good balance of power output.

[0063] According to the characteristics of solar irradiance at different time periods throughout the day and the IV working characteristic curve of the electrolyzer, the energy management device 110 dynamically adjusts the power distribution. The main operation modes are as follows:

[0064] 1) Working condition 1: When S1>S4, that is, when the solar radiation energy reaches the peak at noon (about 12:00-14:00), the external power grid does not work, and the photovoltaic array device 120 supplies power to the energy storage device 140 and the electrolyzer at the same time; at this time, the energy storage device 140 is in a charging state until it is charged to the set target threshold. During this period, the load rate of hydrogen production by electrolysis of water is 90%-100%.

[0065] 2) Working condition 2: When S1<S4, and S1+S2>S4, in the morning or other time periods in the afternoon (about 10:00~12:00 and 14:00~16:00), the external power grid is not working, and the photovoltaic array device 120 and the energy storage device 140 supply power to the electrolyzer at the same time; at this time, the energy storage device 140 is in a discharge state. During this period, the load rate of hydrogen production by electrolysis of water is guaranteed to be 80~100%.

[0066] 3) Operating condition 3: When S1<S4, and S1+S2<S4, the external power grid will be put into operation in other periods, and the external power grid will supply power to the energy storage device 140 and the electrolyzer at the same time. At this time, the energy storage device 140 is in a charging state until it is charged to the set target threshold. During this period, the load rate of hydrogen production by electrolysis of water is guaranteed to be at a low load of 40%.

[0067] In this embodiment, the direct coupling connection mode eliminates the electronic tracking device and the energy buffer device, greatly simplifying the system, and at the same time, has high requirements for the structural matching of the electrolyzer and the photovoltaic array. In the large-scale photovoltaic water electrolysis hydrogen production system, the energy storage device 140 and the energy management device 110 are added, and the system operation mode and control mode are reasonably designed to improve the volatility and instability of the large-scale photovoltaic water electrolysis hydrogen production system, so as to achieve the continuous operation of the water electrolysis hydrogen production device 130, and ensure the high output and efficiency of the water electrolysis hydrogen production device 130.

[0068] Compared with the prior art, the operating conditions of this embodiment are diverse. The user can adjust the power input distribution in time through the energy management device 110 according to the energy state of the photovoltaic array device 120, the energy storage device 140, the external power grid, and the power demand of the electrolyzer, thereby improving the volatility and instability of the large-scale photovoltaic water electrolysis hydrogen production system, achieving the continuous operation of the water electrolysis hydrogen production device 130, and ensuring the high output and efficiency of the water electrolysis hydrogen production device 130. Through the direct coupling system connection method, while ensuring a high utilization efficiency, electronic equipment such as MPPT, batteries, DC / DC converters, inverters, etc. are omitted to make the system more flexible, simple, and economical, while reducing the failure rate, thereby reducing future maintenance costs.

[0069] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0070] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0071] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A water electrolysis hydrogen production system based on photovoltaic power generation, characterized in that: include: Energy management devices, energy storage devices, photovoltaic array devices and water electrolysis hydrogen production devices; The output end of the photovoltaic array device is connected to the input end of the energy storage device and the water electrolysis hydrogen production device, the output end of the energy storage device is connected to the water electrolysis hydrogen production device, the water electrolysis hydrogen production device is also used to connect to an external power grid, and the input end of the energy storage device is also used to connect to the external power grid; The first control end of the energy management device is connected to the control end of the photovoltaic array device, the second control end of the energy management device is connected to the control end of the energy storage device, and the third control end of the energy management device is used to connect to an external power grid; The energy management device is used to control the power supply of the photovoltaic array device, the energy storage device, and the external power grid to the water electrolysis hydrogen production device, and is also used to control the power supply of the photovoltaic array device and the external power grid to the energy storage device.

2. The system for producing hydrogen by electrolysis of water based on photovoltaic power generation according to claim 1, characterized in that: The energy management device is used to obtain the load of the water electrolysis hydrogen production device and the first capacity of the photovoltaic array device, compare the load of the water electrolysis hydrogen production device and the first capacity, and control the power supply of the photovoltaic array device, the energy storage device, and the external power grid to the water electrolysis hydrogen production device according to the comparison result of the load of the water electrolysis hydrogen production device and the first capacity, and control the power supply of the photovoltaic array device and the external power grid to the energy storage device.

3. The system for producing hydrogen by electrolysis of water based on photovoltaic power generation according to claim 2, characterized in that: The energy management device is used for: When the first capacity is greater than the load of the water electrolysis hydrogen production device, controlling the photovoltaic array device to supply power to the energy storage device and the water electrolysis hydrogen production device, wherein the energy storage device is in a charging state; When the first capacity is less than or equal to the load of the water electrolysis hydrogen production device, the sum of the first capacity and the second capacity of the energy storage device is compared with the load of the water electrolysis hydrogen production device, and based on the comparison result of the sum of the first capacity and the second capacity with the load of the water electrolysis hydrogen production device, the photovoltaic array device, the energy storage device, and the external power grid are controlled to supply power to the water electrolysis hydrogen production device, and the photovoltaic array device and the external power grid are controlled to supply power to the energy storage device.

4. The system for producing hydrogen by electrolysis of water based on photovoltaic power generation according to claim 3, characterized in that: The energy management device is used for: When the first capacity is less than or equal to the load of the water electrolysis hydrogen production device, and when the sum of the first capacity and the second capacity is greater than the load of the water electrolysis hydrogen production device, controlling the photovoltaic array device and the energy storage device to simultaneously supply power to the water electrolysis hydrogen production device, wherein the energy storage device is in a discharge state; When the first capacity is less than or equal to the load of the water electrolysis hydrogen production device, and when the sum of the first capacity and the second capacity is less than or equal to the load of the water electrolysis hydrogen production device, the external power grid is controlled to supply power to the energy storage device and the water electrolysis hydrogen production device, wherein the energy storage device is in a charging state.

5. The system for producing hydrogen by electrolysis of water based on photovoltaic power generation according to claim 4, characterized in that: The water electrolysis hydrogen production device is used for: When the first capacity is greater than the load of the water electrolysis hydrogen production device, the water electrolysis hydrogen production load rate is controlled to be 90% to 100%.

6. The system for producing hydrogen by electrolysis of water based on photovoltaic power generation according to claim 4, characterized in that: The water electrolysis hydrogen production device is used for: When the first capacity is less than or equal to the load of the water electrolysis hydrogen production device, and when the sum of the first capacity and the second capacity is greater than the load of the water electrolysis hydrogen production device, the water electrolysis hydrogen production load rate is controlled to be 80% to 100%.

7. The system for producing hydrogen by electrolysis of water based on photovoltaic power generation according to claim 4, characterized in that: The water electrolysis hydrogen production device is used for: When the first capacity is less than or equal to the load of the water electrolysis hydrogen production device, and when the sum of the first capacity and the second capacity is less than or equal to the load of the water electrolysis hydrogen production device, the water electrolysis hydrogen production load rate is controlled to be less than 40%.

8. The system for producing hydrogen from water by electrolysis based on photovoltaic power generation according to any one of claims 1 to 7, characterized in that: It also includes a filter, and the output end of the photovoltaic array device is connected to the input end of the energy storage device and the water electrolysis hydrogen production device through the filter.

9. The system for producing hydrogen from water by electrolysis based on photovoltaic power generation according to any one of claims 1 to 7, characterized in that: It also includes a rectifier, the input end of the rectifier is used to connect to the external power grid, the first output end of the rectifier is connected to the water electrolysis hydrogen production device, and the second output end of the rectifier is connected to the input end of the energy storage device.

10. The system for producing hydrogen from water by electrolysis based on photovoltaic power generation according to any one of claims 1 to 7, characterized in that: It also includes an external power grid switch unit, the input end of the external power grid switch unit is used to connect to the external power grid, the output end of the external power grid switch unit is respectively connected to the input end of the energy storage device and the water electrolysis hydrogen production device, and the control end of the external power grid switch unit is connected to the third control end of the energy management device.

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