A light-hydrogen-electric multimodal flexible coupling system and a collaborative operation method thereof

Abstract

The application discloses a light-hydrogen-electric multi-modal flexible coupling system and a collaborative operation method thereof, and belongs to the technical field of comprehensive utilization of renewable energy resources. The system adopts a coupling architecture of double power supply, double hydrogen production, double hydrogen storage and double hydrogen use, and is matched with an energy management module to realize multi-module collaborative scheduling. The collaborative operation method solves the problems of poor adaptability, low energy efficiency, insufficient reliability and high cost of the existing light-hydrogen-electric coupling system through priority power supply scheduling, dynamic hydrogen production power distribution, hierarchical hydrogen storage and waste heat cascade utilization, and improves the economy, reliability and energy utilization efficiency of the system, and has industrial scale application value.

Description

Technical Field

[0001] This invention relates to the field of comprehensive utilization technology of renewable energy, and in particular to a flexible coupling system of light-hydrogen-electricity multimodal operation and its collaborative operation method. Background Technology

[0002] Driven by the global push for "dual carbon" goals, renewable energy has become a core direction of energy transition. Among these, photovoltaic (PV) power generation, due to its abundant resources and continuously decreasing installation costs, has become the fastest-growing type of renewable energy. According to data from the International Energy Agency (IEA), global PV installations exceeded 1.2 TW in 2024 and are projected to reach 1.5 TW in 2025. China accounts for over 60% of global PV installations. However, the inherent intermittency and volatility of PV power severely restricts large-scale grid connection and efficient utilization. Photovoltaic-hydrogen coupling has become an important path to solve the problem of PV power consumption. The global market size for photovoltaic-hydrogen coupling systems reached $20 billion in 2024 and is projected to exceed $100 billion by 2030. However, existing systems have many shortcomings. 1. The system is rigid but has poor adaptability: A single electrolyzer cannot simultaneously meet the response requirements of rapid photovoltaic power fluctuations and the requirements of stable and efficient hydrogen production. This results in the system either having a delayed response and failing to fully utilize green electricity when photovoltaic power fluctuates, or experiencing accelerated equipment wear and tear due to frequent adjustments, with an overall efficiency of less than 65%. 2. Low energy efficiency: The waste heat generated by fuel cell operation is mostly emitted directly without being effectively recovered, while solid hydrogen storage devices need to consume additional electricity to maintain an operating temperature of 60-90℃, which further reduces the overall energy efficiency of the system; 3. Insufficient reliability: Under extreme weather conditions such as continuous rain, relying solely on photovoltaics and energy storage devices with limited capacity cannot guarantee continuous hydrogen production and energy supply, and cannot meet the needs of industrial-grade continuous hydrogen supply. 4. High cost: The reliance on precious metal catalysts in single proton exchange membrane (PEM) electrolyzers results in high initial investment for the system. At the same time, the single hydrogen storage method cannot balance hydrogen storage density and response speed, further increasing operating costs. Summary of the Invention

[0003] The purpose of this invention is to provide a photo-hydrogen-electric multimodal flexible coupling system and its cooperative operation method to solve the problems of poor adaptability, low energy efficiency, insufficient reliability and high cost of photo-hydrogen-electric coupling systems in the prior art.

[0004] This invention provides a photo-hydrogen-electricity multimodal flexible coupling system, comprising a power supply module, a hydrogen production module, a hydrogen storage module, a hydrogen consumption module, and an energy management module. The power supply module includes a photovoltaic power supply unit, a lithium battery energy storage unit, and a grid backup unit, all three connected via a DC bus. The photovoltaic power supply unit is a photovoltaic module connected to the DC bus via a DC / DC converter to achieve maximum power point tracking. The lithium battery energy storage unit is a lithium battery module connected to the DC bus via a bidirectional DC / DC converter. The grid backup unit is a grid interface connected to the DC bus via an AC / DC converter to achieve AC-to-DC conversion. The system includes DC and grid-connected / off-grid switching; the hydrogen production module comprises a PEM electrolyzer unit and an AEM electrolyzer unit, which are connected in parallel to the DC bus, sharing a pure water supply subsystem and a cooling subsystem, and each is equipped with an independent controllable power interface; the hydrogen storage module comprises a high-pressure gaseous hydrogen storage unit and a solid hydrogen storage unit, which are linked by a solenoid valve group to achieve staged hydrogen storage; the hydrogen consumption module comprises a high-temperature PEMFC unit and a low-temperature PEMFC unit, with the waste heat recovery circuit of the high-temperature PEMFC unit coupled to the heating circuit of the solid hydrogen storage unit; the energy management module is used to collect the operating data of each module and schedule the coordinated operation of each module.

[0005] Furthermore, the pure water supply subsystem includes a pure water tank, a booster pump, a two-stage ion exchanger, and a flow sensor. The two-stage ion exchanger includes cation exchange resin and anion exchange resin. Pure water is distributed to the PEM electrolyzer unit and the AEM electrolyzer unit through a branch valve. The flow rate is dynamically adjusted by the energy management module according to the operating status of the PEM electrolyzer unit and the AEM electrolyzer unit. The inlet water resistivity reaches 18.2 MΩ·cm or higher.

[0006] Furthermore, the cooling subsystem adopts liquid cooling, sharing a cooling pump and heat pipe radiator. The PEM electrolytic cell unit and the AEM electrolytic cell unit are each equipped with an independent PT100 temperature sensor and a temperature control valve. The energy management module maintains the operating temperature of the PEM electrolytic cell unit and the AEM electrolytic cell unit in the range of 60-80℃ by adjusting the opening of the temperature control valve.

[0007] Furthermore, the high-pressure gaseous hydrogen storage unit is a high-pressure gaseous hydrogen storage cylinder with a working pressure of 35 MPa, equipped with a pressure sensor, safety valve, and rapid charge / discharge valve to meet the instantaneous high-flow hydrogen supply requirements; the solid-state hydrogen storage unit is a solid-state hydrogen storage device that uses metal hydrides as the hydrogen storage material, achieving a hydrogen storage density of over 1.5 wt%, and is equipped with a temperature sensor, heating circuit, and auxiliary electric heating element, maintaining the working temperature at 60-90℃ to achieve high-density long-term hydrogen storage.

[0008] Furthermore, the high-temperature PEMFC unit is a high-temperature proton exchange membrane fuel cell with an operating temperature above 90°C. Its waste heat recovery circuit is coupled to the heating circuit of the solid hydrogen storage unit through a 316L stainless steel plate heat exchanger, with a heat exchange efficiency of not less than 85%. The low-temperature PEMFC unit is a low-temperature proton exchange membrane fuel cell with an operating temperature below 80°C. Its low-grade waste heat output terminal is connected to a heating system or a domestic hot water system.

[0009] Furthermore, the energy management module collects voltage, current, temperature, pressure, and flow data of each module via CAN bus or Ethernet, and has a built-in fault diagnosis module that can monitor the operating status of each module in real time and issue early warnings.

[0010] Furthermore, hydrogen leakage sensors are installed inside the cabinets of the hydrogen storage module and the hydrogen consumption module. When the hydrogen concentration reaches the preset value of the lower explosive limit, the hydrogen valve is automatically closed and the explosion-proof fan is started for ventilation.

[0011] This invention also provides a method for the coordinated operation of a photo-hydrogen-electric multimodal flexible coupling system. This method is applicable to the aforementioned multimodal flexible coupling system and includes the following steps: Sp1. Power Supply Side Coordination: The energy management module schedules power supply according to the priority of "PV > Lithium Battery > Grid". When PV power is greater than or equal to the load demand, PV power is used first, and excess power is used to charge the lithium battery or for hydrogen production. When PV power is less than the load demand and the lithium battery SOC is greater than 20%, the lithium battery discharges to supplement the load. When the lithium battery SOC is less than or equal to 20% or there is a fault, the power supply is switched to the grid. Sp2. Hydrogen production side coordination: The energy management module calculates the photovoltaic power change rate ΔP / Δt. When ΔP / Δt>10% / s, the fluctuating power is allocated to the first electrolysis unit; when ΔP / Δt<5% / s, the stable power is preferentially allocated to the second electrolysis unit. Sp3. Hydrogen storage and hydrogen consumption side coordination: When the hydrogen production exceeds the hydrogen consumption demand, hydrogen is preferentially stored in the second hydrogen storage unit. After the second hydrogen storage unit is full, it is stored in the first hydrogen storage unit. When the hydrogen consumption module is started, the first hydrogen storage unit supplies hydrogen preferentially. At the same time, the waste heat of the first fuel cell unit is used to heat the second hydrogen storage unit, and the waste heat after heat exchange preheats the water inlet of the electrolyzer.

[0012] Furthermore, in the power supply side coordination step, the energy management module calculates the difference between the load demand and the output power of the power supply unit in real time, dynamically adjusts the output power of each power supply unit, and when the load power suddenly increases, prioritizes increasing the photovoltaic output power, then adjusts the lithium battery discharge power, and finally switches to grid power supply.

[0013] Furthermore, in the hydrogen production side coordination step, the energy management module monitors the PEM electrolyzer unit and the AEM electrolyzer unit in real time. When the temperature is below 60°C, the cooling flow rate is reduced, and when the temperature is above 80°C, the cooling flow rate is increased to maintain the stable operating temperature of the electrolyzer.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: Firstly, this invention significantly improves system adaptability through multimodal flexible adaptation. By adopting a coupled architecture of dual power supply, dual hydrogen production, dual hydrogen storage, and dual hydrogen use, combined with the coordinated scheduling of the energy management module, the system can dynamically switch operating modes according to photovoltaic power fluctuations and changes in park energy demand. It can adapt to the intermittent fluctuations of photovoltaic power and make full use of green electricity, while ensuring stable and efficient hydrogen production and energy supply. It is suitable for various application scenarios such as industrial parks and distributed energy stations. Compared with existing systems, the adaptability is improved by more than 30%.

[0015] Secondly, this invention can significantly improve system energy efficiency by utilizing energy in a cascade manner. By using the high-temperature waste heat of the high-temperature PEMFC unit to heat the solid-state hydrogen storage unit, it replaces the independent electric heating equipment. At the same time, it uses the waste heat after heat exchange to preheat the water inlet of the electrolyzer, realizing the cascade utilization of thermal energy and increasing the overall energy utilization efficiency of the system to over 82%, which is at least 15% higher than the energy efficiency of existing systems. For a 1MW system, carbon emissions can be reduced by about 30% annually, saving about 200,000 yuan in electricity costs.

[0016] Third, by balancing cost and reliability, this invention effectively improves the economic efficiency of the system. The dual electrolyzer design can allocate hydrogen production tasks according to power characteristics, avoiding frequent adjustments of a single electrolyzer, extending equipment life by more than 20%, and reducing operating costs by 15%. At the same time, the power grid is used as a backup power source, ensuring continuous power supply reliability while maintaining the green electricity utilization rate of the system at more than 90%. This reduces carbon emissions and avoids the high cost of relying on a single energy storage device, reducing the initial investment of the system by about 10%.

[0017] Fourth, this invention can ensure the stable operation of the system through safety protection upgrades. By configuring hydrogen leakage sensors and explosion-proof fans, it can realize real-time monitoring and emergency handling of hydrogen leakage. At the same time, the fault diagnosis module of the energy management module can predict equipment failure 24 hours in advance, and the system availability reaches more than 99.5%, meeting the safety requirements of continuous power supply for industrial applications. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of the photohydrogen-electric multimodal flexible coupling system in this invention. Detailed Implementation

[0020] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] Example 1: This embodiment provides a photohydrogen-electric multimodal flexible coupling system, the hardware connection of which is as follows: Figure 1 As shown: Among them, the photovoltaic power supply unit 1 is connected to the DC bus 4 through a DC / DC converter with MPPT function to achieve maximum tracking of photovoltaic power; the lithium battery energy storage unit 2 is connected to the DC bus 4 through a bidirectional DC / DC converter to support bidirectional charging and discharging control; the grid backup unit 3 is connected to the DC bus 4 through an AC / DC converter to achieve seamless switching between grid connection and off-grid.

[0022] The PEM electrolyzer unit 5 and the AEM electrolyzer unit 6 are connected to the DC bus 4 through independent controllable power interfaces, and they share the pure water supply subsystem 7 and the cooling subsystem 8. The two-stage ion exchanger of the pure water supply subsystem 7 increases the resistivity of pure water to more than 18.2 MΩ·cm, and the heat pipe radiator of the cooling subsystem 8 improves the heat dissipation efficiency by more than 25% compared with the traditional radiator.

[0023] The hydrogen produced by hydrogen production is purified by a purification device and then selected to enter the high-pressure gaseous hydrogen storage unit 9 or the solid hydrogen storage unit 10 through the solenoid valve group 11. The high-pressure gaseous hydrogen storage unit 9 is equipped with a pressure sensor and a safety valve, while the solid hydrogen storage unit 10 is equipped with a temperature sensor, a heating circuit and an auxiliary electric heating element 16.

[0024] The cooling circuit of the high-temperature PEMFC unit 12 is coupled to the heating circuit of the solid hydrogen storage unit 10 through the plate heat exchanger 15, and the waste heat output end of the low-temperature PEMFC unit 13 is connected to the park's heating water network; hydrogen leakage sensors 17 and explosion-proof fans 18 are installed inside the cabinets of the hydrogen storage module and the hydrogen consumption module to ensure the safe operation of the system.

[0025] The energy management module 14 collects the operating data of each module through the CAN bus, sends control commands in real time, and drives the actions of various power converters, valves, switches and other actuators.

[0026] In this embodiment, the multimodal flexible coupling system operates collaboratively under different working conditions as follows: 1. Full photovoltaic power supply: When the photovoltaic power in the park is sufficient, the energy management module 14 controls the DC / DC converter of the photovoltaic power supply unit 1 to work in the maximum power point tracking mode. The excess power is used to charge the lithium battery energy storage unit 2 or to supply the hydrogen production module. At this time, the photovoltaic power is stable and the power change rate is <5% / s. The power is preferentially allocated to the AEM electrolyzer unit 6 for efficient hydrogen production, and the excess hydrogen is preferentially stored in the solid hydrogen storage unit 10.

[0027] 2. Photovoltaic fluctuation conditions: When photovoltaic power fluctuates, the energy management module 14 calculates the power change rate. If the change rate is >10% / s, it adjusts the duty cycle of the controllable power interface of the PEM electrolysis cell unit 5 and allocates the fluctuating power. At the same time, it monitors the temperature of the two electrolysis units in real time and adjusts the cooling flow through the temperature control valve to maintain a stable operating temperature.

[0028] 3. Rapid hydrogen supply mode: When the park needs to supply hydrogen quickly, the energy management module 14 controls the solenoid valve group 11 to open the outlet valve of the high-pressure gaseous hydrogen storage unit 9 to quickly supply hydrogen; when the temperature of the solid hydrogen storage unit 10 is below 60°C, the pump of the plate heat exchanger 15 is accelerated to use the waste heat of the high-temperature PEMFC unit 12 to heat it and maintain the operating temperature.

[0029] 4. Extreme weather conditions: When continuous rainy weather leads to insufficient photovoltaic power, the energy management module 14 first controls the lithium battery energy storage unit 2 to discharge and supplement the power. When the remaining power of the lithium battery energy storage unit 2 is less than 20%, it automatically switches to the grid backup unit 3 for power supply to ensure continuous system operation. At this time, the hydrogen production module stops operating to prioritize the power supply of the core loads in the park. At the same time, the waste heat of the high-temperature PEMFC unit 12 is used to maintain the temperature of the solid hydrogen storage unit 10 to avoid insufficient hydrogen desorption.

[0030] Example 2: This embodiment provides a specific implementation of a photohydrogen-electric multimodal flexible coupling system. The system includes a dual power supply module, a dual hydrogen production module, a dual hydrogen storage module, a dual hydrogen consumption module, an energy management system, and methods for coordinating hydrogen production and hydrogen storage and consumption. The specific implementation methods of each component will be described in detail below.

[0031] Dual Power Supply Module Implementation: The dual power supply module adopts an integrated DC bus architecture, including photovoltaic modules, lithium battery modules, and a grid interface. The photovoltaic modules are polycrystalline silicon solar panels with a power range of 5kW-100kW and a conversion efficiency of no less than 20%. The photovoltaic modules are connected to the DC bus via a DC / DC converter, which employs MPPT (Maximum Power Point Tracking) control with a tracking accuracy of no less than 99.5%. The lithium battery modules are lithium iron phosphate batteries with a capacity range of 10kWh-500kWh. The battery management system (BMS) monitors the battery status in real time, including voltage, current, temperature, and SOC (State of Charge), maintaining the SOC between 20% and 90%. The lithium batteries are connected to the DC bus via a bidirectional DC / DC converter for charge and discharge control. The grid interface is connected via an AC / DC converter, supporting both grid-connected and off-grid modes. The AC / DC converter has a rated power of 10kW-500kW and a power factor of no less than 0.95. The energy management system performs intelligent scheduling based on a preset priority of "photovoltaic > lithium battery > grid". Seamless switching is achieved by controlling the enable signals of each converter and relays, with a switching time of no more than 100ms.

[0032] Implementation of the Dual Hydrogen Production Module: The dual hydrogen production module includes a proton exchange membrane (PEM) electrolyzer and an anion exchange membrane (AEM) electrolyzer, which are connected in parallel. The PEM electrolyzer has a rated power of 10kW-100kW, an operating pressure of 1-3MPa, an operating temperature of 60-80°C, and a hydrogen purity of not less than 99.99%. The AEM electrolyzer has a rated power of 10kW-100kW, an operating pressure of 0.1-0.5MPa, an operating temperature of 30-60°C, and a hydrogen purity of not less than 99.9%. Both electrolyzers are connected to the DC bus via independent DC / DC converters with an efficiency of not less than 95%. The dual hydrogen production module shares a pure water supply and cooling system. The pure water system includes a pure water tank (capacity 100L-1000L), a water pump (flow rate 1-10m³ / h), a flow sensor (accuracy ±0.5%), and an ion exchanger, with an outlet water resistivity of not less than 10MΩ・cm. The cooling system uses liquid cooling, sharing a cooling pump (flow rate 2-15 m³ / h) and a radiator (heat dissipation capacity 10-100 kW). The coolant is a 50% ethylene glycol aqueous solution, and the operating temperature is 10-40°C. The power control of the PEM electrolyzer and AEM electrolyzer is independent, and the hydrogen production task is dynamically allocated by the energy management system according to the fluctuation characteristics of photovoltaic output.

[0033] Implementation of the Dual Hydrogen Storage Module: The dual hydrogen storage module comprises a high-pressure gaseous hydrogen storage cylinder and a solid-state hydrogen storage device. The high-pressure gaseous hydrogen storage cylinder uses a 35MPa or 70MPa carbon fiber composite material cylinder, with a single cylinder capacity of 50L-500L and a total hydrogen storage capacity of 50kg-500kg. It is equipped with a pressure sensor (range 0-100MPa, accuracy ±0.5%), a safety valve (opening pressure 1.3 times the rated pressure), and a rapid charge / discharge valve (response time <100ms). The solid-state hydrogen storage device uses LaNi5-based metal hydride, with a hydrogen storage density of 1.5-2.0wt%. It is equipped with a heating kit (power 5-20kW) and a temperature sensor (range 50-150°C, accuracy ±1°C). The high-pressure gaseous hydrogen storage cylinder and the solid-state hydrogen storage device switch hydrogen paths via a solenoid valve assembly. The solenoid valve assembly includes a normally closed solenoid valve (response time <50ms) and a check valve to prevent hydrogen backflow. The dual hydrogen storage module is connected to the dual hydrogen production module, receives hydrogen from the dual hydrogen production module, and achieves graded hydrogen storage scheduling through valve group linkage.

[0034] Implementation of the Dual-Use Hydrogen Module: The dual-use hydrogen module includes a high-temperature proton exchange membrane fuel cell (PEMFC) and a low-temperature proton exchange membrane fuel cell (PEMFC). The high-temperature PEMFC operates at a temperature of 120-180°C, with a rated power of 10kW-100kW, a power generation efficiency of not less than 50%, and a hydrogen utilization rate of not less than 95%. The low-temperature PEMFC operates at a temperature of 60-80°C, with a rated power of 5kW-50kW, a power generation efficiency of not less than 45%, and a hydrogen utilization rate of not less than 90%. The waste heat generated by the high-temperature PEMFC is coupled to the heating circuit of the solid-state hydrogen storage device through a plate heat exchanger. The plate heat exchanger is made of stainless steel, with countercurrent exchange between the hot and cold sides, an efficiency greater than 80%, a design temperature of 150-180°C for the hot side, and a design temperature of 50-80°C for the cold side. The low-grade waste heat from the low-temperature PEMFC is connected to a heating water pipe through a heat exchanger for domestic heating, with the heating water temperature controllable at 40-60°C. The dual-use hydrogen module is connected to the dual-hydrogen storage module, receives hydrogen from the dual-hydrogen storage module, and adjusts the output power according to the load requirements.

[0035] Implementation of the Energy Management System: The energy management system, as the core control unit, employs an industrial-grade PLC or dedicated controller to execute a collaborative operation strategy. It collects data from each node, performs real-time calculations, and issues control commands, connecting to dual power supply modules, dual hydrogen production modules, dual hydrogen storage modules, and dual hydrogen utilization modules. The energy management system includes a data acquisition module, a control logic module, a human-machine interface module, and a communication module. The data acquisition module collects data from various sensors via CAN bus or Ethernet, with a sampling period not exceeding 100ms. The control logic module includes switching methods and algorithms, hydrogen production control logic, hydrogen storage control logic, thermal management logic, and waste heat recovery and utilization logic. The human-machine interface module uses a touchscreen to display system status and parameters, supporting parameter setting and alarm prompts. The communication module supports industrial communication protocols such as Modbus, CANopen, and Profinet, enabling data exchange with various subsystems.

[0036] Implementation of the Hydrogen Production Side Coordination Method: The hydrogen production side coordination method is executed by the energy management system, which dynamically allocates hydrogen production tasks based on the fluctuation characteristics of photovoltaic power output. The energy management system monitors the photovoltaic power change rate in real time. When the photovoltaic power change rate is greater than 10% / s, power is allocated to the PEM electrolyzer because the PEM electrolyzer is highly adaptable to power fluctuations and has a short response time (<100ms), making it suitable for handling fluctuating power. When the photovoltaic power change rate is less than 5% / s, power is allocated to the AEM electrolyzer because the AEM electrolyzer has high energy efficiency (70-80%), making it suitable for handling stable power. During the transition phase (photovoltaic power change rate between 5%-10% / s), the energy management system dynamically allocates power based on the current load and energy storage status to ensure stable system operation. The energy management system also adjusts the hydrogen production tasks based on the hydrogen storage status of the dual hydrogen storage modules. When the hydrogen storage device is close to full capacity, the hydrogen production power is reduced; when the hydrogen storage device capacity is insufficient, the hydrogen production power is increased.

[0037] Implementation of the Hydrogen Storage and Utilization Synergistic Approach: The hydrogen storage and utilization synergistic approach is executed by the energy management system, implementing a tiered hydrogen storage strategy. The energy management system controls valves based on hydrogen demand, storage status, and temperature data, prioritizing the use of high-pressure gas cylinders for hydrogen supply because of their rapid charging and discharging speed (response time <1s), suitable for meeting rapidly changing hydrogen demands. When the high-temperature PEMFC start-up signal is triggered, the high-pressure gas cylinder outlet valve is opened, and the hydrogen pressure is adjusted to the fuel cell operating pressure (0.15-0.3MPa) via a pressure reducing valve. Simultaneously, the energy management system utilizes the waste heat from the high-temperature PEMFC to provide heat to the solid-state hydrogen storage device, achieving tiered thermal energy utilization. When the solid-state hydrogen storage device temperature is below 60°C, the heating kit is activated, or the high-temperature PEMFC load is increased to improve waste heat output, or the heat exchanger flow rate is adjusted to increase heat transfer. When the solid-state hydrogen storage device temperature reaches 80-90°C, heating is stopped, and this temperature is maintained to optimize hydrogen storage density. The energy management system also adjusts the hydrogen supply strategy according to the load demand of the dual-use hydrogen module. When the load is low, hydrogen from the solid hydrogen storage device is used first because solid hydrogen storage is safe. When the load is high, hydrogen from the high-pressure cylinder is used first because the high-pressure cylinder supplies hydrogen quickly.

[0038] Example 3: In this embodiment, based on Embodiment 2, the switching circuit of the dual power supply module includes photovoltaic modules connected to the DC bus via a DC / DC converter, lithium batteries connected via a bidirectional DC / DC converter, and the grid interface connected via an AC / DC converter. The DC / DC converter adopts a Boost circuit topology, with an input voltage range of 100-500VDC, an output voltage stable at 400VDC, and a conversion efficiency of not less than 97%. The bidirectional DC / DC converter adopts a Buck-Boost circuit topology, with an input voltage range of 200-500VDC, an output voltage stable at 400VDC, and a conversion efficiency of not less than 96%. The AC / DC converter adopts a three-phase full-bridge topology, with an input voltage of 380VAC±10%, 50Hz, an output voltage of 400VDC, a power factor of not less than 0.95, and a THD (total harmonic distortion) of less than 5%. The energy management system achieves seamless switching by controlling the enable signals and relays of each converter. The switching circuit adopts hardware interlocking and software dual protection to ensure safe and reliable switching. When photovoltaic power is insufficient, the energy management system controls relay K1 to open and relay K2 to close, allowing power to be supplied by the lithium battery. When the lithium battery's SOC is below 20%, the energy management system controls relay K2 to open and relay K3 to close, allowing power to be supplied by the grid. During the switching process, a pre-charging circuit ensures a smooth voltage transition and avoids inrush current.

[0039] Example 4: In this embodiment, based on Embodiment 2, the sensor arrangement of the dual power supply module includes a voltage / current sensor located at the photovoltaic output end, a battery management system located at the lithium battery port, and a power quality sensor located at the grid interface. The voltage sensor at the photovoltaic output end is a Hall effect voltage sensor with a range of 0-1000VDC and an accuracy of ±0.2%; the current sensor is a Hall effect current sensor with a range of 0-200A and an accuracy of ±0.5%. The battery management system (BMS) includes a voltage acquisition unit (sampling accuracy ±0.5%), a current acquisition unit (sampling accuracy ±0.5%), a temperature sensor (NTC thermistor, accuracy ±1°C), and a SOC estimation unit. It employs an ampere-hour integration method combined with a Kalman filter algorithm, achieving an SOC estimation accuracy of no less than 2%. The power quality sensor at the grid interface employs a multi-functional power quality analyzer, capable of measuring parameters such as voltage (range 0-400VAC, accuracy ±0.2%), current (range 0-500A, accuracy ±0.5%), frequency (range 45-65Hz, accuracy ±0.01Hz), power factor (accuracy ±0.5%), and harmonics (THD measurement accuracy ±1%). All sensor data is transmitted to the energy management system via CAN bus (transmission rate 1Mbps) or Ethernet (transmission rate 100Mbps), with a sampling period not exceeding 100ms to ensure data real-time performance and accuracy.

[0040] Example 5: In this embodiment, based on Example 2, the PEM electrolyzer and AEM electrolyzer in the dual hydrogen production module are connected to the DC bus via independent DC / DC converters. The PEM electrolyzer uses a Nafion proton exchange membrane with a thickness of 50-150 μm, a platinum-carbon catalyst loading of 0.3-0.5 mg / cm², and an operating current density of 1-2 A / cm². The AEM electrolyzer uses a Sustainion™ XA-7 anion exchange membrane with a thickness of 30-80 μm, a non-precious metal catalyst, and an operating current density of 0.5-1 A / cm². The dual hydrogen production module also includes a shared pure water supply system and cooling system. The pure water system includes a pure water tank (capacity 500L, made of 316L stainless steel), a water pump (flow rate 5 m³ / h, head 30 m), a flow sensor (range 0-10 m³ / h, accuracy ±0.5%), and an ion exchanger (mixed bed type, outlet water resistivity ≥15 MΩ・cm). The cooling system employs liquid cooling, sharing a cooling pump (flow rate 8 m³ / h, head 20 m) and a radiator (heat dissipation capacity 50 kW, using aluminum finned tubes). The coolant is a 50% ethylene glycol aqueous solution, and the operating temperature is controlled between 25-35°C. The cooling system is equipped with temperature sensors (accuracy ±0.5°C) and pressure sensors (accuracy ±1%), and PID control is used to regulate the cooling pump speed to maintain a stable operating temperature of the electrolyzer. The pure water system is coupled to the cooling system via a heat exchanger, utilizing the waste heat from the cooling system to preheat the electrolyzer's feed water, improving energy efficiency.

[0041] Example 6: In this embodiment, based on Embodiment 2, the high-pressure gaseous hydrogen storage cylinder in the dual hydrogen storage module is made of 35MPa carbon fiber composite material, with a single cylinder capacity of 200L, an operating pressure of 35MPa, and a hydrogen storage density of approximately 40g / L. The hydrogen storage cylinder assembly is equipped with a pressure sensor (range 0-40MPa, accuracy ±0.5%), a temperature sensor (measurement 40-85°C, accuracy ±1°C), and a safety valve (opening pressure 37.5MPa, reseating pressure 32MPa). The rapid charge / discharge valve uses an electromagnetically piloted ball valve with a response time <50ms and a flow coefficient Cv=15. The solid-state hydrogen storage device uses LaNi5-based metal hydride, with a hydrogen storage capacity of approximately 1.8wt%, an operating pressure of 0.5-2MPa, and an operating temperature of 60-90°C. The solid-state hydrogen storage device is equipped with a heating kit (power 10kW, using an electric heating element) and a temperature sensor (measurement 50-150°C, accuracy ±1°C). The high-pressure gaseous hydrogen storage cylinder and the solid-state hydrogen storage device switch hydrogen pathways via a solenoid valve assembly. This assembly includes two normally closed solenoid valves (response time <50ms, operating pressure 0-40MPa) and a check valve (to prevent hydrogen backflow). The solenoid valve assembly is controlled by the energy management system, automatically switching based on hydrogen storage status and demand. When the pressure in the high-pressure gaseous hydrogen storage cylinder drops below 5MPa, it automatically switches to the solid-state hydrogen storage device for hydrogen supply; when the temperature of the solid-state hydrogen storage device drops below 60°C, the heating element automatically activates.

[0042] Example 7: In this embodiment, based on Embodiment 2, the waste heat generated by the high-temperature PEMFC in the dual-use hydrogen module is coupled to the heating circuit of the solid-state hydrogen storage device through a plate heat exchanger. The high-temperature PEMFC has a rated power of 50kW, an operating temperature of 160°C, a coolant outlet temperature of 90°C, and a coolant flow rate of 3m³ / h. The plate heat exchanger is made of stainless steel, with a plate spacing of 3mm and a heat exchange area of ​​5m². The hot and cold sides exchange heat counter-currently, with an efficiency greater than 85%. The design temperature for the hot side is 90-160°C, and the design temperature for the cold side is 60-90°C. The heating circuit of the solid-state hydrogen storage device includes a circulating water pump (flow rate 2m³ / h, head 15m), a heating element (power 10kW), and a temperature control valve. The energy management system controls heat transfer by adjusting the heat exchanger flow rate. When the temperature of the solid-state hydrogen storage device is below 60°C, the heat exchanger flow rate is increased; when the temperature reaches 80°C, the flow rate is decreased. The high-temperature PEMFC's coolant circuit uses an ethylene glycol aqueous solution (50%) at an operating pressure of 0.3 MPa, and is equipped with an expansion tank and pressure sensor. The solid-state hydrogen storage unit's heating circuit uses deionized water at an operating pressure of 0.2 MPa, and is also equipped with an expansion tank and pressure sensor. The two circuits exchange heat through a plate heat exchanger, achieving a heat transfer efficiency of over 80%, effectively utilizing the waste heat from the high-temperature PEMFC to maintain the optimal operating temperature of the solid-state hydrogen storage unit.

[0043] Example 8: In this embodiment, based on Embodiment 2, the low-grade waste heat from the low-temperature PEMFC in the dual-use hydrogen module is connected to the heating water pipes via a heat exchanger for domestic heating. The low-temperature PEMFC has a rated power of 30kW, an operating temperature of 80°C, a coolant outlet temperature of 65°C, and a coolant flow rate of 2m³ / h. The heat exchanger is a plate heat exchanger made of stainless steel, with a heat exchange area of ​​3m² and an efficiency greater than 75%. The heating water pipes are PPR pipes with a diameter of DN25, a design water temperature of 60-40°C, and a flow rate of 1.5m³ / h. The energy management system adjusts the heating water temperature according to the ambient temperature and user needs. When the ambient temperature is below 15°C, the heating system is activated; when the ambient temperature is above 20°C, the heating system is deactivated. The heating system is equipped with a three-way regulating valve to adjust the heating water flow rate as needed. The coolant circuit of the low-temperature PEMFC uses an ethylene glycol aqueous solution (30%), with an operating pressure of 0.2MPa, and is equipped with an expansion tank and a temperature sensor. The heating water piping system is equipped with a circulating water pump (flow rate 1.5 m³ / h, head 10 m) and temperature sensors. The energy management system regulates the heating water volume by controlling the speed of the circulating water pump, maintaining a stable indoor temperature of 18-22°C. This waste heat recovery system can save approximately 30% of heating energy consumption annually, improving the overall energy efficiency of the system.

[0044] Example 9: In this embodiment, based on Embodiment 2, the switching method and algorithm of the energy management system includes the following steps: 1. Data Acquisition: Real-time acquisition of photovoltaic power (sampling period 100ms), lithium battery SOC (sampling period 1s), and grid status (sampling period 100ms), including voltage, current, frequency, and phase.

[0045] 2. Status Judgment: The available power source is determined according to the preset priority "PV > Lithium Battery > Grid". When the PV power is greater than the load demand and the system is stable, PV is used first. When the PV power is insufficient, it is determined whether the SOC of the lithium battery is greater than 20%. If it is, the lithium battery is used. If the SOC or power of the lithium battery is insufficient, the grid is used.

[0046] 3. Switching Decision: When power switching is required, the algorithm calculates the switching time window and selects to switch during the load trough period to reduce the switching impact.

[0047] 4. Command Issuance: The energy management system achieves seamless switching by controlling the enable signal of the converter and the relay. The switching sequence is as follows: disconnect the current power relay → wait for 100ms pre-discharge → close the target power relay → start the target power converter.

[0048] 5. Status monitoring: After the switch is completed, continuously monitor the voltage, current and frequency of the target power supply to ensure stable operation; if an abnormality is detected, immediately switch back to the previous power supply or the backup power supply.

[0049] 6. Parameter optimization: Based on historical operating data, optimize the switching threshold and switching time to improve system stability and energy efficiency.

[0050] The algorithm employs fuzzy logic control, comprehensively considering photovoltaic power fluctuations, lithium battery SOC change rates, and load demand change rates to achieve smooth switching. During switching, a pre-charging circuit ensures a smooth voltage transition, avoiding inrush current. The switching time is controlled within 100ms to ensure continuous power supply to the load.

[0051] Example 10: In this embodiment, based on Embodiment 9, the hydrogen production control logic of the energy management system allocates hydrogen production tasks according to the photovoltaic power change rate. The specific implementation method is as follows: 1. Data Acquisition: Real-time acquisition of photovoltaic power (sampling period 100ms), calculation of power change rate ΔP / Δt.

[0052] 2. Rate of Change Judgment: Two thresholds are set: a high threshold of 10% / s and a low threshold of 5% / s. When the photovoltaic power change rate ΔP / Δt > 10% / s, it is judged as a high fluctuation state; when 5% / s < ΔP / Δt ≤ 10% / s, it is judged as a medium fluctuation state; and when ΔP / Δt ≤ 5% / s, it is judged as a low fluctuation state.

[0053] 3. Power Allocation: Under high fluctuation conditions, 80%-100% of the hydrogen production power is allocated to the PEM electrolyzer because of its short response time (<100ms), which adapts well to power fluctuations. Under low fluctuation conditions, 70%-100% of the hydrogen production power is allocated to the AEM electrolyzer because of its high energy efficiency (75-80%). Under moderate fluctuation conditions, power is dynamically allocated based on the current hydrogen storage status. When the hydrogen storage capacity is sufficient, the AEM electrolyzer is used preferentially; when the hydrogen storage capacity is insufficient, the PEM electrolyzer is used preferentially.

[0054] 4. Power regulation: The hydrogen production power regulation adopts PID control with a regulation cycle of 1 second to ensure that the hydrogen production power matches the photovoltaic power and avoids power excess or deficiency.

[0055] 5. Safety protection: Set the maximum operating current and maximum operating pressure of the PEM electrolyzer and AEM electrolyzer. When the threshold is exceeded, the power will be automatically reduced or hydrogen production will be stopped.

[0056] 6. Status monitoring: Real-time monitoring of the electrolyzer's operating status, including voltage, current, temperature, pressure, and hydrogen purity, to ensure safe and stable operation.

[0057] The hydrogen production control logic also considers the hydrogen storage status of the dual hydrogen storage modules. When the hydrogen storage device is close to full capacity (>90%), it automatically reduces the hydrogen production power; when the hydrogen storage device capacity is insufficient (<30%), it automatically increases the hydrogen production power. By dynamically adjusting the allocation of hydrogen production tasks, the overall energy efficiency of the system is optimized, and the utilization rate of renewable energy is improved.

[0058] Example 11: The hydrogen storage control logic of the energy management system controls the valves based on hydrogen demand, storage status, and temperature data. The specific implementation method is as follows: 1. Data Acquisition: Real-time acquisition of high-pressure gaseous hydrogen storage cylinder pressure (sampling period 1s), solid hydrogen storage device temperature (sampling period 1s), and fuel cell start-up signal (sampling period 100ms).

[0059] 2. Valve control: When the fuel cell start signal is triggered, the high-pressure gas cylinder outlet valve is opened, and the hydrogen pressure is adjusted to the fuel cell working pressure (0.15-0.3MPa) through the pressure reducing valve; when the solid hydrogen storage device temperature is below 60°C, the heating kit is activated, or the high-temperature PEMFC load is increased to improve waste heat production, or the heat exchanger flow rate is adjusted to increase heat transfer.

[0060] 3. Staged hydrogen storage strategy: High-pressure gas cylinders are given priority for hydrogen supply because they have a fast hydrogen filling and discharging speed (response time <1s), which is suitable for meeting rapidly changing hydrogen demand; when the pressure of the high-pressure gas cylinder is lower than 5MPa, the system automatically switches to solid-state hydrogen storage device for hydrogen supply; when the temperature of the solid-state hydrogen storage device is lower than 60°C, the heating kit is activated, and heating stops when the temperature reaches 80°C.

[0061] 4. Safety protection: The maximum working pressure of the high-pressure gas cylinder (35MPa) and the maximum working temperature of the solid hydrogen storage device (90°C) are set. When the threshold is exceeded, the relevant valves will be automatically closed and the safety protection measures will be activated.

[0062] 5. Status monitoring: Real-time monitoring of the hydrogen storage device's operating status, including pressure, temperature, flow rate, and hydrogen purity, to ensure safe and stable operation.

[0063] 6. Troubleshooting: When hydrogen leakage or abnormal pressure is detected, immediately close the relevant valves, activate the alarm system, and automatically switch to the backup hydrogen supply path.

[0064] The hydrogen storage control logic also considers the load requirements of the dual-use hydrogen module. When the load is low (<30% of rated load), hydrogen from the solid-state hydrogen storage device is used first because solid-state hydrogen storage offers high safety. When the load is high (>70% of rated load), hydrogen from the high-pressure cylinder is used first because the high-pressure cylinder provides hydrogen quickly. By dynamically adjusting the hydrogen storage strategy, the system operating efficiency is optimized, ensuring a safe and reliable hydrogen supply.

[0065] Example 12: The thermal management logic of the energy management system monitors the high-temperature PEMFC outlet temperature and the solid-state hydrogen storage device temperature. The specific implementation method is as follows: 1. Data Acquisition: Real-time acquisition of the high-temperature PEMFC coolant outlet temperature (sampling period 1s) and the solid hydrogen storage device temperature (sampling period 1s).

[0066] 2. Temperature Control: When the temperature of the solid-state hydrogen storage device is below 60°C, the thermal management logic will take one or a combination of the following measures: a. Increase the high-temperature PEMFC load to increase waste heat production and heat transfer; b. Adjust the heat exchanger flow rate to increase heat transfer efficiency; c. Activate the auxiliary heating kit to directly heat the solid-state hydrogen storage device. When the temperature of the high-temperature PEMFC coolant exceeds 100°C, the backup cooling system will be activated, including: a. Increasing the cooling pump speed to increase the coolant flow rate; b. Activating the auxiliary radiator to increase heat dissipation capacity; c. Adjusting the high-temperature PEMFC load to reduce waste heat production.

[0067] 3. Control Algorithm: A fuzzy PID control algorithm is adopted to adjust control parameters based on temperature deviation and temperature change rate, achieving precise temperature control. The control cycle is 1 second, and the temperature control accuracy is ±2°C.

[0068] 4. Safety protection: Set the maximum operating temperature of the high-temperature PEMFC (180°C) and the minimum operating temperature of the solid hydrogen storage device (50°C). When the threshold is exceeded, the protection measures will be automatically activated, including reducing the load, starting emergency cooling or shutting down the system.

[0069] 5. Status monitoring: Real-time monitoring of the operating status of the heat exchange system, including the inlet and outlet temperatures, flow rate, and pressure of the heat exchanger, to ensure the normal operation of the heat exchange system.

Claims

1. A photo-hydrogen-electric multimodal flexible coupling system, characterized in that, The multimodal flexible coupling system includes a power supply module, a hydrogen production module, a hydrogen storage module, a hydrogen consumption module, and an energy management module. The power supply module includes a photovoltaic power supply unit, a lithium battery energy storage unit, and a grid backup unit, which are coupled together via a DC bus. The photovoltaic power supply unit is a photovoltaic module connected to the DC bus via a DC / DC converter to achieve maximum power point tracking. The lithium battery energy storage unit is a lithium battery module connected to the DC bus via a bidirectional DC / DC converter. The grid backup unit is a grid interface connected to the DC bus via an AC / DC converter to achieve AC to DC conversion and grid-connected / off-grid switching. The hydrogen production module includes a PEM electrolyzer unit and an AEM electrolyzer unit, which are connected in parallel to the DC bus and share a pure water supply subsystem and a cooling subsystem, and each is equipped with an independent controllable power interface. The hydrogen storage module includes a high-pressure gaseous hydrogen storage unit and a solid hydrogen storage unit, which are linked by a solenoid valve group to achieve staged hydrogen storage. The hydrogen module includes a high-temperature PEMFC unit and a low-temperature PEMFC unit, and the waste heat recovery circuit of the high-temperature PEMFC unit is coupled to the heating circuit of the solid hydrogen storage unit. The energy management module is used to collect the operating data of each module and schedule the coordinated operation of each module.

2. The photo-hydrogen-electric multimodal flexible coupling system according to claim 1, characterized in that, The pure water supply subsystem includes a pure water tank, a booster pump, a two-stage ion exchanger, and a flow sensor. The two-stage ion exchanger includes cation exchange resin and anion exchange resin. Pure water is distributed to the PEM electrolyzer unit and the AEM electrolyzer unit through a branch valve. The flow rate is dynamically adjusted by the energy management module according to the operating status of the PEM electrolyzer unit and the AEM electrolyzer unit. The inlet water resistivity reaches 18.2 MΩ·cm or higher.

3. The photo-hydrogen-electric multimodal flexible coupling system according to claim 1, characterized in that, The cooling subsystem adopts liquid cooling and shares a cooling pump and heat pipe radiator. The PEM electrolytic cell unit and the AEM electrolytic cell unit are each equipped with an independent PT100 temperature sensor and a temperature control valve. The energy management module maintains the operating temperature of the PEM electrolytic cell unit and the AEM electrolytic cell unit in the range of 60-80℃ by adjusting the opening of the temperature control valve.

4. The photo-hydrogen-electric multimodal flexible coupling system according to claim 1, characterized in that, The high-pressure gaseous hydrogen storage unit is a high-pressure gaseous hydrogen storage cylinder with a working pressure of 35 MPa. It is equipped with a pressure sensor, a safety valve, and a rapid charge / discharge valve to meet the demand for instantaneous high-flow hydrogen supply. The solid-state hydrogen storage unit is a solid-state hydrogen storage device that uses metal hydrides as the hydrogen storage material. The hydrogen storage density reaches more than 1.5 wt%. It is equipped with a temperature sensor, a heating circuit, and auxiliary electric heating elements. The working temperature is maintained at 60-90℃ to achieve high-density long-term hydrogen storage.

5. The photo-hydrogen-electric multimodal flexible coupling system according to claim 1, characterized in that, The high-temperature PEMFC unit is a high-temperature proton exchange membrane fuel cell with an operating temperature above 90°C. Its waste heat recovery circuit is coupled to the heating circuit of the solid hydrogen storage unit through a 316L stainless steel plate heat exchanger, with a heat exchange efficiency of not less than 85%. The low-temperature PEMFC unit is a low-temperature proton exchange membrane fuel cell with an operating temperature below 80°C. Its low-grade waste heat output terminal is connected to a heating system or a domestic hot water system.

6. The photo-hydrogen-electric multimodal flexible coupling system according to claim 1, characterized in that, The energy management module collects voltage, current, temperature, pressure and flow data of each module via CAN bus or Ethernet. It has a built-in fault diagnosis module that can monitor the operating status of each module in real time and issue early warnings.

7. The photo-hydrogen-electric multimodal flexible coupling system according to claim 1, characterized in that, Hydrogen leakage sensors are installed inside the cabinets of the hydrogen storage module and the hydrogen consumption module. When the hydrogen concentration reaches the preset value of the lower explosive limit, the hydrogen valve is automatically closed and the explosion-proof fan is started for ventilation.

8. A method for the coordinated operation of a photo-hydrogen-electric multimodal flexible coupling system, the method being applicable to the multimodal flexible coupling system described in any one of claims 1-7, characterized in that, Includes the following steps: Sp1. Power Supply Side Coordination: The energy management module schedules power supply according to the priority of "PV > Lithium Battery > Grid". When PV power is greater than or equal to the load demand, PV power is used first, and excess power is used to charge the lithium battery or for hydrogen production. When PV power is less than the load demand and the lithium battery SOC is greater than 20%, the lithium battery discharges to supplement the load. When the lithium battery SOC is less than or equal to 20% or there is a fault, the power supply is switched to the grid. Sp2. Hydrogen production side coordination: The energy management module calculates the photovoltaic power change rate ΔP / Δt. When ΔP / Δt>10% / s, the fluctuating power is allocated to the first electrolysis unit; when ΔP / Δt<5% / s, the stable power is preferentially allocated to the second electrolysis unit. Sp3. Hydrogen storage and hydrogen consumption side coordination: When the hydrogen production exceeds the hydrogen consumption demand, hydrogen is preferentially stored in the second hydrogen storage unit. After the second hydrogen storage unit is full, it is stored in the first hydrogen storage unit. When the hydrogen consumption module is started, the first hydrogen storage unit supplies hydrogen preferentially. At the same time, the waste heat of the first fuel cell unit is used to heat the second hydrogen storage unit, and the waste heat after heat exchange preheats the water inlet of the electrolyzer.

9. The cooperative operation method according to claim 8, characterized in that, In the power supply side coordination step, the energy management module calculates the difference between the load demand and the output power of the power supply unit in real time, dynamically adjusts the output power of each power supply unit, and when the load power suddenly increases, prioritizes increasing the photovoltaic output power, then adjusts the lithium battery discharge power, and finally switches to grid power supply.

10. The cooperative operation method according to claim 8, characterized in that, In the hydrogen production side coordination step, the energy management module monitors the PEM electrolyzer unit and the AEM electrolyzer unit in real time. When the temperature is below 60°C, the cooling flow rate is reduced, and when the temperature is above 80°C, the cooling flow rate is increased to maintain the stable operating temperature of the electrolyzer.

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