A small-sized light energy electrolysis hydrogen production system based on MPPT constant power control
Patent Information
- Application Number
- CN202610992606.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-06
- Publication Date
- 2026-10-30
AI Technical Summary
[0005]有鉴于此，本发明旨在提出一种基于MPPT恒功率控制的小型光能电解制氢系统，以解决现有小型光能电解制氢系统中，光伏输出功率波动导致电解槽运行不稳定、电极寿命缩短、系统整体效率偏低的问题
1.本发明采用MPPT电导增量法与恒功率双闭环控制相结合的策略，在光伏侧实现最大能量捕获，在负载侧实现恒功率稳定输出，兼顾了能量利用效率与电解槽运行稳定性。
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Figure CN123005458A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of renewable energy hydrogen production technology, and in particular relates to a small-scale photovoltaic electrolysis hydrogen production system based on MPPT constant power control. Background Technology
[0002] In recent years, the global energy structure transformation has accelerated, and hydrogen energy, as a zero-carbon emission secondary energy source, has received widespread attention. Utilizing photovoltaic power generation to drive water electrolysis for hydrogen production is one of the important pathways to achieve green hydrogen production. In small-scale photovoltaic electrolysis hydrogen production systems, the photovoltaic output power is significantly affected by natural conditions such as light intensity and ambient temperature, exhibiting significant intermittency and fluctuation. Proton exchange membrane (PEM) electrolyzers require high stability of input power; frequent power fluctuations can lead to accelerated electrode corrosion, decreased hydrogen purity, and shortened membrane electrode lifespan.
[0003] In existing technologies, the coupling methods between photovoltaic (PV) and electrolyzers are mainly divided into two categories: direct coupling and indirect coupling. Direct coupling has a simple structure, but it is difficult to dynamically match the PV output characteristics with the electrolyzer load characteristics, and the system efficiency is greatly affected by changes in sunlight. Indirect coupling achieves power smoothing through energy storage or grid regulation, but this increases system complexity and cost. In addition, existing small-scale hydrogen production systems have relatively crude power control strategies and lack refined control methods for constant power operation of the electrolyzer, resulting in low overall system energy efficiency and insufficient operational stability.
[0004] In summary, a small-scale photoelectric electrolysis hydrogen production system based on MPPT constant power control is proposed. Summary of the Invention
[0005] In view of this, the present invention aims to propose a small-scale photovoltaic electrolysis hydrogen production system based on MPPT constant power control, in order to solve the problems of unstable operation of electrolyzer, shortened electrode life and low overall system efficiency caused by photovoltaic output power fluctuations in existing small-scale photovoltaic electrolysis hydrogen production systems.
[0006] To achieve the above objectives, the present invention adopts the following technical solution to provide a small-scale photovoltaic electrolysis hydrogen production system based on MPPT constant power control, comprising: The MPPT converter adjusts the photovoltaic array to always operate near the maximum power point and boosts the output voltage to the voltage level required by the DC bus. The energy storage battery is connected to the DC bus via a bidirectional DC-DC converter for power buffering. The constant power control module is located between the DC bus and the PEM electrolyzer to maintain a constant input power to the PEM electrolyzer.
[0007] Furthermore, the MPPT converter uses the incremental conductance method to track the maximum power point of the photovoltaic array in real time, and adjusts the duty cycle through the Boost circuit to ensure that the photovoltaic array always operates near the maximum power point.
[0008] Furthermore, when the photovoltaic output power is greater than the rated power of the electrolytic cell, the excess electrical energy is charged to the energy storage battery via a bidirectional converter; when the photovoltaic output power is insufficient or the light is interrupted, the energy storage battery discharges to supplement the power deficit and maintain the constant power operation of the electrolytic cell.
[0009] Furthermore, the constant power control module employs a Buck step-down circuit, forming a dual closed-loop control structure with a constant power outer loop and a current inner loop.
[0010] Furthermore, the outer ring compares the rated power setting of the electrolytic cell with the actual power feedback, and outputs a current reference value through the PI regulator.
[0011] Furthermore, the inner loop compares the current reference value with the actual current feedback and adjusts the duty cycle of the Buck circuit to keep the input power of the electrolytic cell constant.
[0012] Furthermore, the PEM electrolyzer receives stable DC power output from the constant power control module, and anodic oxygen evolution reaction and cathodic hydrogen evolution reaction occur on both sides of the membrane electrode, respectively.
[0013] Furthermore, it also includes a hydrogen detection unit to monitor the hydrogen concentration at the hydrogen production end in real time.
[0014] Furthermore, the hydrogen detection unit includes an MQ8 hydrogen sensor, an STM32 microcontroller, and an OLED display.
[0015] Beneficial effects: 1. This invention adopts a strategy that combines the MPPT conductivity increment method with constant power dual closed-loop control to achieve maximum energy capture on the photovoltaic side and constant power stable output on the load side, thus balancing energy utilization efficiency and electrolytic cell operation stability.
[0016] 2. This invention introduces an energy storage battery and a bidirectional DC-DC converter as a power buffer. Through adaptive adjustment of charging and discharging, it effectively mitigates the impact of light fluctuations on the electrolytic cell and expands the stable operating range of the system.
[0017] 3. This invention adopts a modular design, with the photovoltaic array, converter, energy storage unit, electrolyzer, and detection unit being relatively independent. This facilitates parameter adjustment and functional expansion according to actual application scenarios, making it suitable for teaching experiments and distributed small-scale hydrogen production applications. Attached Figure Description
[0018] Figure 1A flowchart of the process for a photovoltaic electrolysis hydrogen production system; Figure 2 Simulation model diagram of a photovoltaic electrolysis hydrogen production system. Detailed Implementation
[0019] Referring to the accompanying drawings, this embodiment provides a small-scale photovoltaic electrolysis hydrogen production system based on MPPT constant power control, including a photovoltaic power generation unit, an MPPT converter, an energy storage battery, a bidirectional DC-DC converter, a constant power control module, a PEM electrolyzer, and a hydrogen detection unit.
[0020] A photovoltaic power generation unit consists of a photovoltaic array, which is responsible for converting solar radiation into direct current electricity.
[0021] The MPPT converter uses the incremental conductance method to track the maximum power point of the photovoltaic array in real time. It adjusts the duty cycle through the Boost circuit to keep the photovoltaic array working near the maximum power point and boosts the output voltage to the voltage level required by the DC bus.
[0022] The energy storage battery is connected to the DC bus via a bidirectional DC-DC converter, forming a power buffer. When the photovoltaic output power exceeds the rated power of the electrolyzer, the excess electrical energy is charged to the energy storage battery through the bidirectional converter; when the photovoltaic output power is insufficient or the sunlight is interrupted, the energy storage battery discharges to supplement the power deficit and maintain the constant power operation of the electrolyzer.
[0023] The outer loop compares the rated power setting of the electrolytic cell with the actual power feedback. The rated power setting is 3kW, and the current reference value is output through the PI regulator. The inner loop compares the current reference value with the actual current feedback. The current reference value is dynamically calculated by the outer loop PI regulator based on the power deviation. Under rated operating conditions, it is about 83.6A. The duty cycle of the Buck circuit is adjusted to keep the input power of the electrolytic cell constant.
[0024] The PEM electrolyzer, as the core hydrogen production device, receives stable DC power from the constant power control module, and the oxygen evolution reaction at the anodic electrode and the hydrogen evolution reaction at the cathode occur on both sides of the membrane electrode, thereby realizing hydrogen production by water electrolysis.
[0025] The hydrogen detection unit includes an MQ8 hydrogen sensor, an STM32 microcontroller, and an OLED display. It monitors the hydrogen concentration at the hydrogen production end in real time and issues an alarm signal when the concentration exceeds a set threshold to ensure the safe operation of the system.
[0026] The system workflow is as follows: The photovoltaic array outputs DC power, which is then processed by the MPPT converter for maximum power point tracking and voltage boosting before being connected to the DC bus; the constant power control module draws power from the bus and stabilizes the output power at the rated power of the electrolyzer through dual closed-loop control; when the output voltage meets the requirements of the electrolysis reaction, the electrolyzer starts working, and water molecules undergo decomposition reactions under the action of the electrodes, such as... Figure 1 As shown, with increased sunlight, the output power of the photovoltaic modules increases, the current in the electrolyzer increases, and the hydrogen production reaction accelerates. Conversely, with decreased sunlight, the system output power decreases, the electrolysis current decreases, and the reaction rate slows down. To prevent changes in sunlight from significantly affecting the electrolyzer, the power conversion unit must maintain a constant output within a certain range, while using control methods to suppress excessive current surges.
[0027] During system operation, the DC bus overvoltage protection threshold is set to 350V, the electrolytic cell overcurrent protection threshold to 100A, and the electrolytic cell temperature protection threshold to 85℃. When the voltage exceeds 350V, the current exceeds 100A, or the temperature exceeds 85℃, the protection circuit immediately disconnects or reduces its output to ensure the normal operation of the system.
[0028] The overall system simulation modeling mainly focuses on the design of three parts: photovoltaic power generation, energy storage management, and electrolytic hydrogen production. Figure 2 As shown, the rational configuration and effective utilization of energy flow are achieved through the cooperation of various modules. The photovoltaic power generation system is the energy input port. It uses the MPPT algorithm to regulate the output of the photovoltaic array, incorporating factors such as light intensity and temperature into the modeling process to affect power generation efficiency. The boost converter circuit raises the DC power generated by the photovoltaic modules to a certain bus voltage. The system also includes a power monitoring module, which can collect the power generated by the photovoltaic system in real time for subsequent energy dispatch.
[0029] The system also includes a power monitoring module that can collect the power generated by the photovoltaic array in real time for subsequent energy dispatch. Simulation results show that under rated operating conditions, the photovoltaic array outputs approximately 5000W. After passing through the MPPT converter and Boost circuit, the DC bus voltage is maintained at 280V±2V with a voltage fluctuation rate of 0.71%. The power output from the constant power control module to the electrolyzer is stable at 3000W±150W, with power fluctuations controlled within ±5%. Physical testing shows that the system can continuously produce hydrogen under natural sunlight conditions, with the electrolyzer operating voltage stable at 35.9V and a hydrogen production rate of approximately 24L / min. The hydrogen detection device accurately responds to and displays the hydrogen concentration, verifying the feasibility and reliability of the system design.
[0030] The embodiments of the present invention disclosed above are only for illustrating the present invention. The embodiments do not describe all details exhaustively, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention.
Claims
1. A small-scale photovoltaic electrolysis hydrogen production system based on MPPT constant power control, characterized in that, include: The MPPT converter adjusts the photovoltaic array to always operate near the maximum power point and boosts the output voltage to the voltage level required by the DC bus. The energy storage battery is connected to the DC bus via a bidirectional DC-DC converter for power buffering. The constant power control module is located between the DC bus and the PEM electrolyzer to maintain a constant input power to the PEM electrolyzer.
2. The small-scale photovoltaic electrolysis hydrogen production system based on MPPT constant power control according to claim 1, characterized in that: The MPPT converter uses the incremental conductance method to track the maximum power point of the photovoltaic array in real time. It adjusts the duty cycle through the Boost circuit, thereby ensuring that the photovoltaic array always operates near the maximum power point.
3. A small-scale photovoltaic electrolysis hydrogen production system based on MPPT constant power control according to claim 1, characterized in that: When the photovoltaic output power is greater than the rated power of the electrolyzer, the excess electrical energy is charged to the energy storage battery through the bidirectional converter; when the photovoltaic output power is insufficient or the light is interrupted, the energy storage battery discharges to make up for the power deficiency and maintain the constant power operation of the electrolyzer.
4. A small-scale photovoltaic electrolysis hydrogen production system based on MPPT constant power control according to claim 1, characterized in that: The constant power control module uses a Buck step-down circuit, forming a dual closed-loop control structure with a constant power outer loop and a current inner loop.
5. A small-scale photovoltaic electrolysis hydrogen production system based on MPPT constant power control according to claim 4, characterized in that: The outer ring compares the rated power setting of the electrolytic cell with the actual power feedback, and outputs a current reference value through the PI regulator.
6. A small-scale photovoltaic electrolysis hydrogen production system based on MPPT constant power control according to claim 5, characterized in that: The inner loop compares the current reference value with the actual current feedback and adjusts the duty cycle of the Buck circuit to keep the input power of the electrolytic cell constant.
7. A small-scale photovoltaic electrolysis hydrogen production system based on MPPT constant power control according to claim 1, characterized in that: The PEM electrolyzer receives stable DC power output from the constant power control module, and oxygen evolution reaction occurs at the anodic electrode and hydrogen evolution reaction at the cathode electrode, respectively.
8. A small-scale photovoltaic electrolysis hydrogen production system based on MPPT constant power control according to claim 1, characterized in that: It also includes a hydrogen detection unit to monitor the hydrogen concentration at the hydrogen production end in real time.
9. A small-scale photovoltaic electrolysis hydrogen production system based on MPPT constant power control according to claim 8, characterized in that: The hydrogen detection unit includes an MQ8 hydrogen sensor, an STM32 microcontroller, and an OLED display.