A hydrogen fuel cell super-charging pile system and working method

Abstract

The present application relates to hydrogen fuel cell technology field, specifically to a kind of hydrogen fuel cell super charging pile system and working method, including hydrogen fuel cell power generation module, energy storage system and charging module, respectively through DC / DC converter connection to direct current bus;Multi-source hydrogen supply module is configured with at least two different types of hydrogen supply interface, check valve is equipped on each hydrogen supply pipeline;Main control module generates power scheduling instruction of fuel cell according to the deviation of energy storage system state of charge and target interval, and instantaneous power gap is automatically compensated by energy storage system;System does not have grid-connected interface to external power grid, to operate independently in off-grid mode.The present application is through the direct current bus structure of fuel cell and energy storage battery parallel connection, so that system has black start capability, load instantaneous response capability and fuel continuous supply capacity, realizes the off-grid independent power supply not dependent on power grid.

Description

Technical Field

[0001] This invention relates to the field of hydrogen fuel cell technology, specifically to a hydrogen fuel cell supercharging pile system and its operating method. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] With the rapid development of new energy vehicles, the construction of charging infrastructure has become a crucial link. Currently, electric vehicle charging stations mainly rely on the power grid for power supply, which can easily exacerbate the grid load during peak electricity consumption periods. To solve this problem, energy storage charging station systems have emerged, which reduce dependence on the power grid by combining supercapacitors and lithium batteries. However, such systems have limited energy storage capacity under long-term high-power charging demands, making it difficult to meet continuous and stable power supply requirements. While the introduction of hydrogen fuel cells into charging facilities has gradually met power supply needs, the system architecture lacks off-grid operation capability and still relies on or expects grid support, making independent deployment impossible in areas without grid coverage. Summary of the Invention

[0004] To address the technical problems mentioned above, this invention provides a hydrogen fuel cell supercharging pile system and its operating method. Through a parallel DC bus design of "fuel cell + energy storage battery" and a multi-source hydrogen supply module, the system can achieve black start capability, instantaneous load response capability, and continuous fuel supply capability without relying on the power grid, ensuring power supply reliability in off-grid scenarios.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: The first aspect of the present invention provides a hydrogen fuel cell supercharging station system, comprising: At least one hydrogen fuel cell power generation module is connected to a DC bus via a first DC / DC converter; The energy storage system is connected to the DC bus via a second DC / DC converter; At least one charging module is connected to the DC bus via a third DC / DC converter for outputting charging power to the charging pile; The multi-source hydrogen supply module has its output end connected to the hydrogen inlet of the hydrogen fuel cell power generation module. The multi-source hydrogen supply module is equipped with at least two different types of hydrogen supply interfaces, and a check valve is installed on the hydrogen supply pipeline corresponding to each hydrogen supply interface. The main control module is communicatively connected to the hydrogen fuel cell power generation module, energy storage system, and charging module, respectively. The main control module is configured to: use the energy storage system as the main buffer of the DC bus, calculate the target power of fuel cell scheduling based on the deviation between the state of charge of the energy storage system and the target interval, and control the fuel cell to execute scheduling instructions at a preset ramp rate, with the energy storage system compensating for the instantaneous power gap. The system does not have a grid-connected interface for feeding power to the external power grid and operates independently in off-grid mode.

[0006] As a further limitation, the main control module is also configured to perform black start control, specifically: when the system is in a shutdown state, it establishes the DC bus voltage through the energy storage system or independent starting power supply and supplies power to the auxiliary system of the hydrogen fuel cell power generation module. After the hydrogen fuel cell power generation module starts, it outputs power to the DC bus, and the energy storage system switches to buffer mode.

[0007] As a further limitation, the main control module is also configured to perform load response control, specifically: The energy storage system is connected in parallel to the DC bus as the main buffer. Based on the deviation between the state of charge of the energy storage system and the target range, and combined with the real-time output / input power of the energy storage system and the total load power of the system, the target power for fuel cell scheduling is calculated using the steady-state power balance formula. Based on the SOC partition scheduling logic and SOC differential power adjustment compensation, the scheduling target power is corrected; The hydrogen fuel cell power generation module is controlled to execute the modified scheduling instructions according to the preset ramp rate.

[0008] As a further limitation, the main control module is also configured to perform hydrogen supply switching control, specifically: monitoring the main hydrogen source pressure; when the pressure drops to a first threshold, controlling the hydrogen fuel cell power generation module to actively reduce load and pre-charge the backup hydrogen source pipeline; when the pressure drops to a second threshold, performing synchronous switching between the main and backup pipelines, wherein the second threshold is greater than the minimum allowable inlet pressure of the hydrogen fuel cell power generation module; after the switching is completed, controlling the hydrogen fuel cell power generation module to restore power; power fluctuations during the switching process are compensated by the energy storage system.

[0009] As a further limitation, the main control module is also configured to perform active shutdown protection. Specifically, when the external energy input of the system is lower than the system standby power consumption, the pressure of all hydrogen sources is lower than the minimum operating pressure plus the safety margin, and the state of charge of the energy storage system is lower than the shutdown protection threshold, active shutdown is performed, which sequentially stops the external power supply, shuts down the hydrogen fuel cell power generation module, reduces the power consumption of unnecessary equipment, and keeps the state of charge of the energy storage system at the shutdown protection threshold and no longer decreases.

[0010] As a further limitation, the hydrogen supply pipeline of the multi-source hydrogen supply module is equipped with a main solenoid valve and a safety solenoid valve connected in series to form a dual-redundant interlock control. A pressure sensor is installed between the two solenoid valves to monitor the pressure changes between the valves. When an abnormal pressure fluctuation is detected, the system closes the two solenoid valves to cut off the hydrogen supply.

[0011] As a further limitation, it also includes a photovoltaic power generation system and an electrolysis hydrogen production system. The photovoltaic power generation system is connected to the DC bus through a fourth DC / DC converter, and the electrolysis hydrogen production system is connected to the multi-source hydrogen supply module. When the photovoltaic power is greater than the charging load demand, the main control module controls the excess electrical energy to be converted into hydrogen through the electrolysis hydrogen production system and stored in the hydrogen storage container of the multi-source hydrogen supply module.

[0012] As a further limitation, the main control module is configured as follows: when the system is equipped with a photovoltaic power generation system, a power allocation rule of "photovoltaic priority, energy storage buffer, and fuel cell backup" is adopted; when the system is not equipped with a photovoltaic power generation system, it operates in a "pure hydrogen plus energy storage" mode, with hydrogen supplied to the hydrogen fuel cell power generation module by the multi-source hydrogen supply module, the hydrogen fuel cell power generation module supplying power to the DC bus as the main power source, and the energy storage system used to balance instantaneous load fluctuations, provide black start energy, and compensate for power gaps during power switching.

[0013] As a further limitation, it also includes a thermal management subsystem, which includes at least a first independent heat dissipation circuit and a second independent heat dissipation circuit. The first independent heat dissipation circuit is connected to the hydrogen fuel cell power generation module, the second independent heat dissipation circuit is connected to the charging interface of the charging module, the third independent heat dissipation circuit is connected to the power electronic devices, and the fourth independent heat dissipation circuit is connected to the energy storage system. The central thermal management controller independently adjusts the cooling power of each circuit according to the temperature sensor data of each circuit.

[0014] A second aspect of the present invention provides a method for operating a hydrogen fuel cell supercharging station system, comprising the following steps: The energy storage system or independent starting power supply establishes the DC bus voltage to power the auxiliary system of the hydrogen fuel cell power generation module. After the hydrogen fuel cell power generation module starts up, it outputs power to the DC bus. Based on the deviation between the state of charge of the energy storage system and the target range, a power scheduling command for the hydrogen fuel cell power generation module is generated. The hydrogen fuel cell power generation module executes the command according to the preset ramp rate, and the instantaneous power gap is compensated by the energy storage system during the process. The cooling power of the first independent heat dissipation circuit and the second independent heat dissipation circuit are independently controlled based on the temperature of the hydrogen fuel cell power generation module and the charging interface temperature of the charging module. Monitor the main hydrogen source pressure. When the pressure drops to the first threshold, control the hydrogen fuel cell power generation module to actively reduce the load and pre-charge the backup hydrogen source pipeline. When the pressure drops to the second threshold, perform synchronous switching between the main and backup pipelines. Monitor hydrogen concentration. When the concentration exceeds the first threshold, start ventilation. When the concentration exceeds the second threshold, cut off the hydrogen supply to the fault area and reduce the load. When the concentration exceeds the third threshold, cut off the hydrogen supply to the entire system and shut down.

[0015] Compared with existing technologies, one or more of the above technical solutions have the following beneficial effects: The fuel cell and energy storage battery are connected to the DC bus through their respective DC / DC converters to form a parallel architecture. The system does not have a grid-connected interface to feed power to the external power grid, realizing independent off-grid operation. It does not need to rely on the municipal power grid to provide start-up power, frequency support or power backup. It can be independently deployed and operated in areas without grid coverage, where grid expansion costs are high or grid connection is not allowed (such as remote highway service areas, newly developed areas, islands, mines, temporary emergency charging sites, etc.). It fundamentally solves the technical problems of traditional charging piles relying on grid power supply, aggravating grid load during peak electricity consumption periods, and being unable to be deployed in areas without grid coverage.

[0016] Furthermore, the main control module generates power scheduling commands for the fuel cell based on the deviation between the state of charge of the energy storage system and the target range. This allows the fuel cell to no longer need to directly track rapidly changing loads, but instead to track slowly changing states of charge. This ensures that the system maintains stable power output when the load changes instantaneously, solving the problem of mismatch between the power response capability of the fuel cell and load changes in off-grid scenarios. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0018] Figure 1 This is a schematic diagram of a hydrogen fuel cell supercharging pile system provided in one or more embodiments of the present invention; Figure 2 This is a schematic diagram of the principle of a multi-source hydrogen supply module provided in one or more embodiments of the present invention; Figure 3 This is an electrical schematic diagram of a hydrogen fuel cell supercharging pile system provided in one or more embodiments of the present invention; Figure 4 This is a schematic diagram of the thermal management subsystem structure provided in one or more embodiments of the present invention. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0022] The meanings of the relevant terms used in this plan are as follows.

[0023] Fuel cell system: A device that uses an electrochemical reaction to convert the chemical energy in fuel into electrical energy, typically consisting of fuel, oxidant, electrolyte, anode, and cathode.

[0024] DC / AC (Direct Current to Alternating Current) converter: A device that converts the direct current generated by a fuel cell stack into alternating current.

[0025] DC / DC (Direct-to-Direct-to-Direct-Voltage Converter): A converter used to adjust DC voltage to provide the required voltage to other devices in a system.

[0026] To address the issues identified in the aforementioned background technologies, this solution first clarifies that the target deployment scenarios for hydrogen fuel cell supercharging pile systems are areas without grid coverage, where grid expansion costs are extremely high, or where grid connection is not permitted (such as remote highway service areas, newly developed zones, islands, mines, and temporary emergency charging sites). In these scenarios, the system cannot rely on the grid for startup power, frequency support, or power backup; instead, it must rely on itself to achieve black start, load following, and uninterrupted power supply. Therefore, the issue of "power supply reliability in off-grid scenarios" must be resolved.

[0027] Based on this, this solution adopts a layered and progressive approach to address the aforementioned technical problems, specifically including: The first layer (basic layer): Off-grid DC microgrid architecture. Through the parallel DC bus design of "fuel cell + energy storage battery" and the multi-source hydrogen supply module, the system has black start capability, instantaneous load response capability and continuous fuel supply capability without relying on the grid, fundamentally solving the power supply reliability problem in off-grid scenarios.

[0028] The second layer (control layer): a three-stage power allocation logic. Building upon the first layer, a power allocation rule of "photovoltaic priority, energy storage buffer, and fuel cell backup" is established based on the state of charge of photovoltaic (optional) and energy storage, as well as load requirements. This solves the problem of coordinated control among multiple energy sources and improves the overall energy efficiency of the system.

[0029] The third layer (protection layer): multi-loop independent heat dissipation and central coordination. During high-power charging and discharging, a multi-loop independent heat dissipation system is designed to address the differentiated heat dissipation needs of fuel cells, energy storage batteries, power electronic devices, and charging interfaces, solving the problem of differentiated heat dissipation needs of multiple heat sources and ensuring that each component operates within its optimal temperature range.

[0030] The fourth layer (safety layer): a three-tiered hydrogen leak response mechanism. Addressing the inherent safety risks of hydrogen use, a tiered response system is established to resolve safety issues related to hydrogen use and achieve full-chain protection from early warning to emergency shutdown.

[0031] Example 1: The first layer (basic layer) of this solution uses a parallel DC bus design of "fuel cell + energy storage battery" and a multi-source hydrogen supply module to enable the system to have black start capability, instantaneous load response capability and continuous fuel supply capability without relying on the power grid, thus solving the power supply reliability problem in off-grid scenarios.

[0032] like Figure 1 As shown, the hydrogen fuel cell supercharging station system adopts a DC bus architecture. Multiple hydrogen fuel cell power generation modules are connected to the DC bus via corresponding first DC / DC converters. The energy storage system is connected to the DC bus via a second DC / DC converter, and the charging module is connected to the DC bus via a third DC / DC converter. The DC bus connects to the thermal management subsystem, low-voltage converter, and other components (such as safety protection devices, lighting facilities, and the main control module) via DC / AC converters. The low-voltage converter outputs low-voltage electricity for use by various components of the system. The system does not have a grid-connected interface for feeding power to the external power grid and operates independently in off-grid mode.

[0033] In this embodiment, all DC / DC converters can be bidirectional DC / DC converters.

[0034] The hydrogen fuel cell power generation module uses proton exchange membrane fuel cell stacks connected in parallel. In this embodiment, the rated power of each stack is 100kW-120kW. Each stack adjusts its output to the DC bus voltage through a corresponding first DC / DC converter. The bus voltage is generally 450-750V.

[0035] The energy storage system can use lithium iron phosphate battery packs with a total capacity of 150kWh-200kWh. The rated voltage is matched with the DC bus, and the charging and discharging control is achieved through a bidirectional DC / DC converter.

[0036] The charging module includes at least one DC fast charging gun with a maximum charging current of 500A and a maximum charging power of 350kW. It supports mainstream charging standards such as CCS and CHAdeMO and draws power from the DC bus through a third DC / DC converter.

[0037] The output of the multi-source hydrogen supply module is connected to the hydrogen inlet of the fuel cell power generation module. The module is equipped with three hydrogen supply interfaces: a high-pressure hydrogen cylinder interface (working pressure 70MPa), a pipeline hydrogen supply interface (working pressure 2MPa), and a field hydrogen production interface.

[0038] like Figure 2 As shown, the multi-source hydrogen supply module includes a hydrogen supply pipeline. A main solenoid valve and a safety solenoid valve are connected in series on the pipeline, forming a dual-redundant interlocking control. The main solenoid valve is responsible for on / off control, while the safety solenoid valve can be an integrated type, used for pressure reduction and safety protection. The two are connected in series to achieve dual-stage protection. When both solenoid valves are open simultaneously, hydrogen is supplied to the fuel cell. A pressure sensor is installed between the two solenoid valves to monitor pressure changes between them. When abnormal pressure fluctuations are detected, the system closes both solenoid valves, prioritizing the cutting off of the hydrogen supply.

[0039] The hydrogen supply pipeline is also equipped with a backup valve and a heat exchanger, which is used to regulate the temperature of the hydrogen supplied to the fuel cell.

[0040] The multi-source hydrogen supply module supports multiple hydrogen supply methods. In this embodiment, hydrogen supply is provided by high-pressure hydrogen cylinder group, pipeline hydrogen supply, and on-site hydrogen production. Each hydrogen supply method is equipped with a corresponding check valve on the pipeline.

[0041] In this embodiment, the high-pressure hydrogen cylinder supply system includes eight 70MPa high-pressure hydrogen cylinders with a total hydrogen storage capacity of 80kg. It is equipped with a pressure reducing valve to reduce the pressure of the 70MPa high-pressure hydrogen to 0.6MPa required for the operation of the fuel cell.

[0042] In this embodiment, the hydrogen supply pipeline is connected to the external hydrogen pipeline network via a standardized interface, designed to operate at a pressure of 2 MPa, and equipped with a flow regulating valve and a pressure sensor. The on-site hydrogen production and supply system employs PEM water electrolysis technology, with a hydrogen production capacity of 5 Nm³. 3 It has a capacity of [number] h and is equipped with a small hydrogen purification unit and a buffer hydrogen storage tank. Three hydrogen supply methods can be flexibly switched according to actual application scenarios, improving the system's adaptability and reliability.

[0043] By adopting a parallel DC bus architecture of "fuel cells + energy storage batteries," coupled with multi-source hydrogen supply modules and a thermal management subsystem, and without a grid-connected interface to feed power to the external power grid, the system achieves independent off-grid operation. This system does not rely on the grid for start-up power, frequency support, or power backup. It can be independently deployed and operated in areas without grid coverage, where grid expansion costs are high, or where grid connection is not permitted (such as remote highway service areas, islands, mines, and temporary emergency charging sites). This solves the technical problems of traditional charging piles relying on grid power, exacerbating grid load during peak electricity consumption periods, and being unable to be deployed in areas without grid coverage.

[0044] Based on the above embodiments, the system may further include a photovoltaic power generation system and a water electrolysis hydrogen production system. The photovoltaic power generation system is connected to the DC bus via a fourth DC / DC converter. When the photovoltaic power exceeds the charging load demand, the main control module controls the excess electrical energy to be converted into hydrogen through the water electrolysis hydrogen production system, and then stored in the hydrogen storage container of the multi-source hydrogen supply module via a compressor; when the photovoltaic power is insufficient, the hydrogen fuel cell power generation module and / or the energy storage battery system provide supplementary power. This optional implementation further improves the system's energy self-sufficiency rate and renewable energy absorption capacity.

[0045] To ensure power supply reliability in off-grid scenarios, this system has been specifically designed in the following aspects: 1. Black start capability.

[0046] In off-grid scenarios, the system cannot rely on the power grid for startup. This system employs a tiered startup power mechanism to ensure reliable startup under any conditions.

[0047] The operating modes of an energy storage system include discharge mode, charging mode, and buffer mode: Discharge mode: The energy storage system actively outputs power to the DC bus and is used as the main power source; Charging mode: The energy storage system absorbs power from the DC bus for charging; Buffer mode: The energy storage system is connected in parallel to the DC bus in voltage source mode, actively clamping the bus voltage and automatically compensating for power gaps when the load fluctuates, thus maintaining the stability of the bus voltage.

[0048] like Figure 3 The system electrical schematic diagram shown shows that the high-voltage DC distribution cabinet is connected to the charging pile host, UPS (battery pack), lithium battery (energy storage) system and fuel cell system respectively, and is equipped with reserved DC input and AC input interfaces.

[0049] The primary starting power source is a UPS (battery pack), configured independently of the main power battery within the system. It is pre-charged before the system starts and float-charged by the main power battery or fuel cell via a bidirectional charger during normal system operation. Its main task is to provide the energy required for the first start-up of the fuel cell auxiliary equipment, control system, and main contactor when the power battery is completely depleted (equivalent to an independent starting power source).

[0050] The second-stage starting power source is a lithium battery (energy storage) system. After the system is powered on, if the first-stage UPS does not meet the starting requirements, the battery management system detects the voltage of the main power battery. If the voltage is higher than the minimum operating voltage (corresponding to 10% state of charge), the main power battery independently maintains the bus voltage and controls the high-voltage DC contactor to drive the fuel cell to start up to the working state.

[0051] The energy flow during startup is as follows: After the control system powers on and performs a self-test, it closes the contactor on the DC bus, and the power battery provides a stable voltage to the DC bus (completed in milliseconds). Subsequently, the power battery on the DC bus drives the auxiliary systems of the fuel cell (including air compressor, hydrogen circulation pump, cooling water pump, cooling fan, etc.). After the auxiliary systems start, the fuel cell stack begins a chemical reaction to generate electricity.

[0052] In this embodiment, the startup sequence of the auxiliary system follows the safe sequence of "self-test - hydrogen circuit - cooling - air - stack pressure build-up - load". The power-on self-test initialization ensures that the controller and power supply are ready. The hydrogen circulation is started to purge the hydrogen to avoid corrosion caused by the hydrogen-air interface of the fuel cell. Then the cooling water pump is started for circulation (the fan is started and stopped according to the stack temperature) to ensure that the stack reaches the appropriate reaction temperature. At the same time, the temperature and humidity of the air entering the stack are regulated. Finally, the air compressor is started for slow start and staged load loading to avoid corrosion and performance degradation caused by high potential.

[0053] When the fuel cell system experiences an auxiliary engine startup malfunction or fails to ignite, the system immediately implements a tiered safety protection strategy: First, pause the startup process, lock the power output and cut off the high-voltage output circuit. At the same time, shut down the hydrogen-air intake passage, quickly depressurize and purge the anode and cathode chambers to eliminate the internal mixed gas, and strictly control the hydrogen-air pressure difference to avoid damaging the proton exchange membrane. The thermal management system maintains low-flow circulation and suspends temperature control to prevent abnormal temperature accumulation or low-temperature freezing blockage in the reactor body. It also locks all fault states and retains operating data to avoid dangerous operations such as forced loading and repeated high-frequency switching of the medium, thus avoiding problems such as single-cell reverse polarity, catalyst corrosion, and membrane damage.

[0054] During the recovery phase, the system prioritizes the three-retry automatic mechanism. After each failure, it is statically reset and the intake parameters are optimized and the start-up pace is slowed down. After multiple failed starts, it automatically exits the automatic start-up mode and enters a static cooling state. After the fault diagnosis is completed and the hardware and pipeline status is verified to be correct, the fault code is manually cleared, the entire area is forced to be replaced, and the system is adjusted to a low threshold light load start mode to complete the re-ignition. After the stack voltage is stable and normal, the system is gradually restored to the standard operating conditions.

[0055] Taking a 100kW fuel cell system as an example, the auxiliary start-up power requires approximately 5-15kW, lasting about 30-90 seconds (depending on ambient temperature), with a total energy consumption of approximately 0.1-0.4kWh. For energy storage systems with a capacity of 150kWh or more, the pre-stored electricity is sufficient to complete hundreds of starts.

[0056] By constructing a tiered startup power mechanism, the system possesses reliable black-start capability even when completely off-grid and without any external power support. When the system is in a shutdown state, the energy storage system or UPS (battery bank) establishes the DC bus voltage and supplies power to the fuel cell auxiliary system. After the fuel cell starts, it outputs power to the DC bus, and the energy storage system switches from discharge mode to buffer mode (i.e., it operates as a voltage source in parallel with the DC bus, acting as a main buffer to compensate for instantaneous power fluctuations). Taking a typical system as an example, the total energy consumption for auxiliary startup is approximately 0.1-0.4 kWh, while the energy storage system has a capacity of over 150 kWh, with pre-stored power sufficient to complete hundreds of startups. This ensures reliable startup of the system in any state, whether during initial deployment or after shutdown, solving the black-start problem in off-grid scenarios.

[0057] 2. Instantaneous load response capability.

[0058] The power response time of fuel cells is on the order of seconds, while the power change time of electric vehicle charging demand is on the order of milliseconds, a difference of 3-4 orders of magnitude. This system adopts a two-layer control strategy of "inertial bus + slow tracking scheduling" to solve this problem.

[0059] At the physical layer, the DC bus is always actively clamped by the power battery (the energy storage system is connected in parallel to the DC bus in voltage source mode via a bidirectional DC / DC converter, which is equivalent to directly connecting the power battery to the bus in terms of control effect). The voltage of the power battery determines the bus voltage. When the load of the charging pile increases instantaneously, the bus voltage tends to decrease, and the power battery management system immediately increases the discharge current (microsecond-level response) to make up for the power gap; the same applies when the load decreases, the power battery absorbs the excess energy.

[0060] Regarding key parameters, the maximum discharge rate (C-rate) of the power battery should be at least greater than twice the maximum power of the charging pile divided by the battery capacity. For example, a 200kW charging pile paired with a 400kWh power battery (a 0.5C rate can support 200kW).

[0061] At the control layer, the control system does not directly send "power follows load" commands to the fuel cell, but instead sends "power follows state of charge target" commands. A state of charge operating range is set (e.g., 40%-60%). When the state of charge is below the lower limit, the fuel cell increases its output power; when the state of charge is above the upper limit, the fuel cell is instructed to reduce its power or enter standby mode. Since the state of charge changes on a minute-by-minute basis, the fuel cell's response capability is sufficient.

[0062] The core logic of the above control strategy can be summarized as follows: the power battery is connected in parallel to the DC bus as a main buffer; the state of charge (SOC) of the power battery is monitored in real time; based on the deviation between the SOC and the target range (e.g., 40%-60%), a power scheduling command for the fuel cell is generated; the fuel cell executes the command at a preset ramp rate, during which the power battery compensates for instantaneous power shortages. In this way, the fuel cell no longer needs to directly track rapidly changing loads, but instead tracks slowly changing SOCs, thus completely solving the matching problem between the fuel cell and the load dynamics.

[0063] Based on the deviation between the state of charge and the target range, a power scheduling command for the fuel cell is generated, including: determining the basic power balance formula, combining the state of charge determination constraint correction and the core boundary power constraint to obtain the peak shaving and valley filling standard scheduling formula, and integrating them to obtain the scheduling command.

[0064] Step S1: Define core parameters: The total load power of the system. Real-time output / input power for energy storage (positive for discharging, negative for charging). To dispatch power for fuel cell output; Steady-state power balance core formula: ; Modified fuel cell scheduling target power (basic type): .

[0065] Step S2: Determine constraint corrections based on the SOC state of charge.

[0066] Step S201: Set the energy storage state of charge (SOC) control range, specifically as follows: SOC lower limit threshold: (Deep discharge is prohibited to protect the energy storage battery); SOC upper limit threshold: (Overcharging is prohibited to protect the energy storage battery); The system's stable operating range is between the upper and lower limits of SOC.

[0067] Step S202: SOC partition scheduling logic; (1) High SOC range satisfy This is the high SOC range; at this time, the energy storage takes the lead in bearing the entire load, and the fuel cell operates at reduced power or shuts down, only supplementing the part of the energy storage that is not discharged (if any). in, To maximize the energy storage discharge power, the output of the hydrogen fuel cell must be no less than 0 (to avoid accidental restart after shutdown).

[0068] (2) Normal SOC range satisfy This is within the normal SOC range; at this time, power is evenly distributed / smoothly scheduled according to the load, the fuel cell outputs power according to the load average, and the energy storage smooths out load power fluctuations. in, This is to achieve average load power, ensure stable system operation, and reduce frequent start-stop cycles of the fuel cell.

[0069] (3) Low SOC range satisfy This is the low SOC range; at this time, the energy storage is limited to discharge and priority is given to replenishing power, the fuel cell is operating at full power, and at the same time it undertakes the load and charges the energy storage. in, Fuel cell rated power, The maximum charging power for energy storage is limited, and the output of the hydrogen fuel cell does not exceed the rated value.

[0070] Step S203: Calculation of SOC differential power adjustment compensation; Define SOC deviation: ; in, Set values ​​for SOC. This is the real-time value of SOC; Fuel cell power compensation: ; in, This is the SOC power regulation ratio coefficient (calibrated according to system characteristics, unit: kW / %).

[0071] The fuel cell scheduling instruction (revised) is as follows: ; in, This is the target value for SOC.

[0072] Step S3: Core boundary power constraint.

[0073] To ensure the safe and stable operation of the system, the following power constraints must be met: Fuel cell output limitations: (Negative power is prohibited; power consumption must not exceed the rated power.) Energy storage power constraints: (The negative sign indicates charging, not exceeding the maximum charging and discharging power). This is the maximum charging power for energy storage. This represents the maximum discharge power of the energy storage. Fuel cell ramp rate constraints: , The maximum ramp rate (i.e., the preset ramp rate mentioned above), unit: kW / s, to avoid power surges that could damage the hydrogen fuel cell.

[0074] Step S4: Standard scheduling formula for peak shaving and valley filling.

[0075] During peak load periods, the fuel cell operates at full capacity, while the energy storage system discharges in tandem to compensate for the load shortfall; the corresponding calculation formula is: (at this time (Positive value indicates energy storage and discharge).

[0076] During periods of low load, the fuel cell maintains a minimum stable power output, with excess power used to charge the energy storage system; the corresponding calculation formula is: (at this time (Negative, energy storage charging). in, This is the minimum stable power output of the fuel cell (to avoid low-power shutdown).

[0077] Step S5: Integrate the above logic and form instructions suitable for rapid application on the engineering site in the form of piecewise formulas: ; in, This is the maximum output of the fuel cell (usually equal to the rated power). Real-time discharge power for energy storage (output on demand within the normal range).

[0078] Verification: The hot start time of a fuel cell, from receiving a command to outputting a specified power, is ≤60 seconds (typical value), and the cold start time is ≤180 seconds, while the response time of a power battery is ≤10 milliseconds, a time difference of over 6000 times. The energy required by the power battery within 60 seconds is: assuming the load jumps from 50kW to 200kW, with a shortfall of 150kW, lasting 60 seconds = 2.5kWh. For a 400kWh battery, this only utilizes 0.625% of its capacity, which is feasible.

[0079] Therefore, through the above design, the time difference between the response time of the fuel cell (hot start ≤ 60 seconds, cold start ≤ 180 seconds) and the response time of the power battery (≤ 10 milliseconds) is compensated by the power battery, and the system's external output power remains stable.

[0080] This solution resolves the fundamental contradiction between the slow response (seconds) of fuel cells and the rapid load changes (milliseconds) of charging piles through a two-layer control strategy of "inertial bus + slow tracking scheduling". Specifically, the energy storage system is connected in parallel to the DC bus as a main buffer. The state of charge (SOC) of the energy storage system is detected, and a power scheduling command for the fuel cell is generated based on the deviation between the SOC and the target range. The fuel cell executes the command according to a preset ramp rate, and the energy storage system compensates for instantaneous power gaps during this process. The fuel cell no longer needs to directly track rapidly changing loads, but instead tracks slowly changing SOCs, ensuring that the system maintains stable power output when the load changes instantaneously. This solves the core problem of the mismatch between the power response capability of fuel cells and load changes in off-grid scenarios.

[0081] 3. Continuous fuel supply capability.

[0082] When the multi-source hydrogen supply module needs to switch from the main hydrogen source to the backup hydrogen source, the fuel cell inlet pressure will briefly drop during the switching process. To address this issue, this system employs a three-stage smooth switching strategy to ensure uninterrupted power supply.

[0083] (1) Prediction and load reduction before switching: A pressure sensor is installed at the outlet of the main hydrogen source pipeline. When the pressure drops to the first threshold (20 bar), the system issues a warning that "the main hydrogen source is about to be exhausted" and sends a command to the fuel cell to linearly reduce its output power to the "power to be switched" level (e.g., 30 kW) within 30 seconds. The purpose of load reduction is to extend the residual gas usage time of the main hydrogen source and reduce the energy impact at the moment of switching, making it easier for the power battery to compensate.

[0084] (2) Pre-charging of the backup pipeline: At the same time as issuing the load reduction command, the control system opens the outlet valve of the backup hydrogen source in advance (but keeps the valve at the fuel cell stack inlet closed), so that the backup pipeline (between the outlet valve and the stack inlet valve) is filled with high-pressure hydrogen and the pressure reaches the rated value (e.g., 350 bar or 700 bar). This pre-charging process takes about 1 to 2 seconds and is completed in parallel with the load reduction process.

[0085] (3) Seamless switching execution: When the main hydrogen source pressure drops to the second threshold (still higher than the minimum allowable inlet pressure of the fuel cell, such as 8 bar), the control system simultaneously closes the main pipeline valve and opens the backup valve at the fuel cell stack inlet. Since the backup pipeline has been pre-charged, the stack inlet pressure can instantly recover to the rated value, and the switching action itself takes less than 100 milliseconds. During this period, the fuel cell output power may drop briefly, but the power battery automatically generates additional power to compensate for the shortfall within milliseconds, and the fluctuation of the charging pile's external output power can be controlled within 1%.

[0086] After the switch is completed, the control system will control the fuel cell power to slowly climb from the power to be switched to the target value within 60 seconds, and the power gap during the climb will still be made up by the power battery.

[0087] Regarding the determination of the first and second thresholds during the handover period; Typical high-pressure hydrogen storage cylinders operate at pressures of 35 MPa (350 bar) and 70 MPa (700 bar), with 5 MPa (350 bar) being the mainstream pressure. These storage cylinders come with built-in pressure regulating valves, allowing for primary pressure reduction of 10-50 bar. Hydrogen pipelines are typically designed to operate at pressures of 4-12 MPa (40-120 bar), with medium-pressure designs for urban hydrogen distribution ranging from 1.6 MPa to 4 MPa (16-40 bar). Electrolysis-based hydrogen production often uses a direct storage or output pressure of 3 MPa (30 bar).

[0088] In this embodiment, hydrogen is supplied by pipeline transportation and hydrogen production by water electrolysis, with high-pressure hydrogen storage cylinders as backup. The obvious phenomenon of hydrogen depletion is pressure drop. Using 20 bar as the first protection threshold fully considers the protection of fuel cells. The core principle is to allow sufficient redundancy time for the residual gas in the main hydrogen source to complete the unloading and pre-charging operations.

[0089] ; The minimum permissible inlet pressure for a fuel cell (e.g., 5 bar); This is a margin for dynamic pressure fluctuations (typically 2-3 bar). Total time for unloading (30 seconds) and pre-charging (2 seconds); The rate of pressure drop at the main hydrogen source (which needs to be monitored in real time by a pressure sensor).

[0090] Using 8 bar as the second threshold (switching threshold) is a further protection measure for the fuel cell system; here, 8 bar represents the stack protection level. The core principle is to ensure that the fuel cell inlet pressure remains above the minimum allowable value after switching, while also allowing sufficient response time for the power battery.

[0091] Therefore, dynamic adjustments are made based on fuel cell load demand: ; The rate of pressure decrease of the main hydrogen source; Valve switching time (<100ms); For safety factors (typically 1.5-2). Example: If the main hydrogen source pressure drop rate is 0.5 bar / s, then... In practice, 8 bar is used to cover extreme operating conditions.

[0092] Regarding the design of high-pressure surge protection and pressure reducing valves, considering the slight differences in pressure among the three hydrogen sources, the safety solenoid valve can be an integrated safety valve with pressure reducing function commonly used in automotive fuel cell systems (its core functions are pressure reducing and stabilizing + safety valve + overcurrent protection solenoid valve + check valve + filter). Here, the safety valve inlet pressure supports a maximum of 35-75 MPa, and the outlet pressure is stable at 1.8~3 MPa (18~30 bar), supporting direct input to the hydrogen fuel cell system (there is usually a fine-tuning pressure reducing valve before the stack inlet, sufficient to reduce the pressure from 1.8~3 MPa to 0.6 MPa before entering the stack). Simultaneously, to prevent backflow and counterflow during switching between different hydrogen sources, check valves are added to different hydrogen source pipelines.

[0093] Because the power battery is always connected in parallel to the bus, it can instantly compensate for any power shortfall of the fuel cell, ensuring that the charging pile's power supply is uninterrupted. The fuel cell's output power will experience controllable fluctuations, which are limited to between 30kW and 150kW through a three-level smooth switching strategy, with a change rate ≤5kW / s (achieved through active load reduction), thus having no adverse impact on the fuel cell's lifespan.

[0094] This solution employs a three-level smooth switching strategy to achieve seamless switching between the main and backup hydrogen sources for the multi-source hydrogen supply module, ensuring uninterrupted power supply. When the pressure of the main hydrogen source drops to the first threshold, the system actively reduces the load on the fuel cell to the switching power and pre-charges the backup pipeline. When the pressure drops to the second threshold, the main valve is simultaneously closed and the backup valve is opened, with the switching action taking less than 100 milliseconds. Power fluctuations during the switching process are compensated by the parallel energy storage system, and the power output fluctuation of the charging pile can be controlled within 1%. This mechanism solves the core problem of "charging pile interruption when hydrogen runs out or when switching gas sources" in off-grid scenarios, ensuring the continuity of fuel supply.

[0095] 4. Active shutdown and restart protection.

[0096] To prevent the system from shutting down passively due to energy depletion and becoming unable to restart, this system is equipped with active shutdown protection logic.

[0097] The system will perform a proactive controlled shutdown when all of the following conditions are met: (1) The system detects whether a photovoltaic power input is connected based on the status of the external DC / AC input interface. If connected, it determines whether the photovoltaic power generation is lower than the system's standby power consumption (e.g., at night or on a severely cloudy day). If the system is not equipped with a photovoltaic power generation system, this step is skipped. (2) All hydrogen sources (main and backup) are under pressure lower than the minimum operating pressure plus a safety margin; (3) The state of charge of the power battery is lower than the shutdown protection threshold (configurable, typical value is 15%).

[0098] When three conditions are met simultaneously—that is, photovoltaic power generation power < system standby power consumption, all hydrogen source (main and backup) pressure < minimum operating pressure + safety margin, and power battery state of charge < shutdown protection threshold—the system determines that it cannot obtain net energy input from any source, and that continued discharge will cause irreversible damage to the power battery and deplete the reserves required for the next start-up. At this time, shutdown is executed.

[0099] The active shutdown sequence includes: stopping external power supply, shutting down the fuel cell and performing a safety purging, reducing the power consumption of non-essential equipment while retaining only the core monitoring module, and the battery management system forcibly disconnecting the main discharge contactor of the main power battery while retaining the low-power voltage monitoring circuit, so that the state of charge of the main power battery remains at the shutdown protection threshold and no longer decreases.

[0100] After the system shuts down, the core monitoring module continuously monitors wake-up sources, including hydrogen source pressure recovery (such as replacing the hydrogen cylinder group), photovoltaic voltage recovery (daytime arrival), and remote wake-up commands. When any wake-up source is triggered, the system executes the aforementioned black start procedure to restart, prioritizing charging the main power battery to restore its state of charge to a safe level.

[0101] This solution avoids the risk of a system being unable to restart due to passive shutdown caused by energy depletion by setting up active shutdown protection logic. When the system determines that it cannot obtain net energy input from any source (photovoltaic power is lower than standby power consumption, all hydrogen source pressures are lower than the safety threshold, and the energy storage system's state of charge is lower than the shutdown protection threshold), it executes an active controlled shutdown, sequentially stopping external power supply, shutting down the fuel cell and performing a safety purging, reducing the power consumption of unnecessary equipment, and keeping the energy storage system's state of charge at the protection threshold to prevent further decline. After the system shutdowns, it continuously monitors the wake-up source, and automatically performs a black start to restore power supply when the hydrogen source recovers, the photovoltaic system recovers, or a remote wake-up command is received. This mechanism solves the core problem of "system shutdown and subsequent restart" in off-grid scenarios, forming a complete closed loop from startup to shutdown and restart.

[0102] The second layer (control layer) builds upon the first layer by establishing power allocation rules based on the state of charge of photovoltaic (optional) and energy storage, as well as load requirements. This addresses the issue of coordinated control among multiple energy sources and improves the overall energy efficiency of the system.

[0103] When the system is equipped with a photovoltaic (PV) power generation system (connected to the DC bus via a fourth DC / DC converter), a power allocation rule of "PV priority, energy storage buffer, and fuel cell backup" is adopted. Specifically: (1) The control system monitors the status of the entire station through UPS power supply, then controls the power battery to establish a DC bus to provide high voltage power supply, and controls the DC / AC to provide external AC.

[0104] (2) Based on the comparative analysis of the energy demand of charging piles and the power generation of photovoltaic power, the power battery is used to balance the instantaneous fluctuation of the load, and the photovoltaic and fuel cell are dynamically adjusted.

[0105] (3) When the photovoltaic power exceeds the load demand, start the hydrogen production power supply and the matching compressor to start the electrolysis of water to produce hydrogen. The compressor pressurizes the hydrogen and stores it in the hydrogen cylinder. Based on the remaining photovoltaic power and the state of charge of the power battery, ensure that the state of charge is within the normal operating range (e.g., 20%-80%). When the state of charge is below the lower limit, control the power battery to charge through the DC / DC converter; when the main hydrogen cylinder is full, switch the valve group to pressurize the auxiliary hydrogen cylinder; when the hydrogen cylinder is full, stop the hydrogen production system and the compressor, and charge the power battery with the remaining photovoltaic power; when the power battery is fully charged to the upper limit (e.g., 95%), adjust the photovoltaic output power through the DC / DC converter to balance the load demand, and reserve some power in the power battery for normal shutdown of the fuel cell.

[0106] (4) When there is no load demand, all the electricity generated by the photovoltaic system is used for hydrogen production by water electrolysis until the main and backup hydrogen cylinders are full. After that, the power battery is charged at maximum power through the DC / DC converter; when the power battery is fully charged, the photovoltaic output power is adjusted to balance the internal load and control system consumption, and the entire system enters standby mode to wait for the load demand of the charging pile.

[0107] (5) When the load demand is greater than that of the photovoltaic system, the photovoltaic system maintains maximum power point tracking output. The remaining demand power is checked to see if it is greater than the minimum output power of the fuel cell: if it is less and the state of charge of the power battery is within the normal range, the fuel cell is charged at high voltage and in high-voltage standby mode, waiting for the start command. At this time, the demand power is supplemented by the power battery. When the state of charge is lower than the lower limit (e.g., 20%), a fuel cell start command is issued. The fuel cell draws power from the DC bus, controls the auxiliary system to work, performs air bypass purging, opens the hydrogen supply valve, and the fuel cell starts supplying hydrogen. The output power of the fuel cell is adjusted to output to the DC bus through the DC / DC converter. The output power setting value is the demand power plus the minimum charging power of the power battery. When the battery state of charge is higher than the upper limit (e.g., 80%) and the load demand is greater than that of the photovoltaic system, the fuel cell maintains minimum power operation. When the load demand is less than that of the photovoltaic system and the state of charge is higher than the recovery threshold (e.g., 90%), the fuel cell stops and is in high-voltage standby mode, preparing for the next start.

[0108] (6) When there is no light in the system (night), the hydrogen production system and compressor are in standby mode with minimum energy consumption. The output power of the fuel cell follows the load response of the charging pile. At the same time, the system switches between cylinder groups based on the hydrogen cylinder pressure and provides a hydrogen cylinder replacement reminder.

[0109] (7) When the system is not illuminated and the hydrogen pressure is insufficient, the bus voltage is controlled by the power battery, and the load demand of the charging pile is adjusted by the DC / DC converter to ensure that the state of charge of the power battery is maintained at the minimum retention level (such as 20%). The entire system stops supplying external power, and the remaining battery power is used as the power source for the next start-up. Energy storage is restored after the hydrogen tank and photovoltaic are replenished.

[0110] When the system is not equipped with a photovoltaic power generation system, it operates in a "pure hydrogen + energy storage" mode: hydrogen is supplied to the fuel cell power generation module from a multi-source hydrogen supply module, the fuel cell power generation module acts as the main power source to supply power to the DC bus, and the energy storage system acts as a buffer to balance instantaneous load fluctuations, provide black start energy, and compensate for power gaps during fuel cell startup and power switching. The energy management strategy is simplified as follows: based on the deviation between the energy storage system's state of charge and the target range, a power scheduling command for the fuel cell is generated, and the fuel cell executes the command at a preset ramp rate, during which the energy storage system compensates for instantaneous power gaps.

[0111] The third layer (protection layer) of this solution is to design a multi-loop independent heat dissipation system to address the differentiated heat dissipation needs of fuel cells, energy storage batteries, power electronic devices and charging interfaces during high-power charging and discharging processes. This system solves the problem of differentiated heat dissipation needs of multiple heat sources and ensures that each component operates within the optimal temperature range.

[0112] The thermal management subsystem adopts a multi-loop independent heat dissipation design, and the system principle is as follows: Figure 4 As shown: The first loop is the fuel cell heat dissipation loop, which uses a water-ethylene glycol mixture as the cooling medium and operates in a temperature range of 65-75℃. It is equipped with a variable frequency water pump, radiator and temperature control valve.

[0113] In this embodiment, water pump A generates power to supply coolant, which is then sent to the hydrogen fuel cell through valve A. The heated coolant is divided into two paths: one path passes through an ion exchanger to remove conductive ions from the coolant and then returns to the hydrogen fuel cell through valve A; the other path passes through heat exchanger B and radiator A in sequence to cool down and then returns to the inlet of water pump A to continue the circulation.

[0114] The second circuit is the heat dissipation circuit for the energy storage battery, with the operating temperature controlled between 15-35℃, using a combination of air cooling and liquid cooling plates.

[0115] In this embodiment, the coolant in the circuit is drawn from the inlet of water pump A, pressurized by water pump B, and then passes through radiator B and energy storage system in sequence. After being heated by the energy storage system, it returns to the inlet of water pump B.

[0116] The third circuit is a heat dissipation circuit for power electronic devices, mainly targeting the power devices of DC / DC converters and charging modules, with a maximum heat dissipation power of 30-40kW.

[0117] In this embodiment, the coolant for this circuit is drawn from the water tank, pressurized by the water pump C, passes through each DC / DC converter and DC / AC converter, is cooled by the radiator C, and returns to the inlet of the water pump C.

[0118] The fourth circuit is the heat dissipation circuit for the charging interface, which adopts an independent liquid cooling system to ensure that the interface temperature does not exceed 65°C during charging.

[0119] In this embodiment, the coolant in the circuit comes from the outlet of the water tank and radiator B. The coolant from the water tank is pressurized by the water pump C and divided into two paths by the valve B. One path is cooled by the radiator C and then sent to the charging pile through the valve C. After absorbing the heat from the charging pile, it returns to the inlet of the water pump C. The other path flows out from the valve B, mixes with the coolant from the outlet of the radiator B, and is sent to the multi-source hydrogen supply module. After absorbing the heat from the multi-source hydrogen supply module, it is sent to the charging pile through the valve C. Coolant from the outlet of radiator B is fed into valve C and the multi-source hydrogen supply module. After passing through the multi-source hydrogen supply module, it is mixed at the inlet of valve C and then sent to the charging pile through valve C.

[0120] The valves A, B, and C mentioned above are all multi-way valves used to divert coolant and realize the cascade utilization of the coolant's heat absorption capacity.

[0121] The central thermal management controller independently adjusts the cooling power of each circuit based on temperature sensor data. The main control module has a built-in energy management algorithm that dynamically allocates the output power of the fuel cell and the energy storage battery based on charging load demand, energy storage battery state of charge, fuel cell efficiency curve, and system temperature status, and works in coordination with the thermal management controller.

[0122] Through the above-mentioned multi-loop independent heat dissipation design, this solution achieves differentiated independent temperature control for four heat sources: fuel cell temperature difference ≤ 5℃, energy storage battery module temperature difference ≤ 3℃ with temperature control accuracy ±0.5℃, power electronic device maximum heat dissipation power up to 40kW, charging interface temperature not exceeding 65℃, and the central thermal management controller dynamically coordinates the cooling power of each loop, fundamentally solving the problem of local overheating caused by multiple heat sources sharing a single heat dissipation loop, significantly improving system thermal safety and equipment lifespan.

[0123] The fourth layer (safety layer) addresses the inherent safety risks of hydrogen use by establishing a tiered response system to resolve safety issues related to hydrogen use and achieve full-chain protection from early warning to emergency shutdown.

[0124] Specifically, the system deploys hydrogen concentration sensor arrays in key locations such as the hydrogen storage tank area, pressure reducing valve assembly, fuel cell stack anode inlet / outlet, ventilation openings, and the top and bottom of the compartment to monitor the hydrogen concentration in each area in real time (in percentage of the lower explosive limit, %LEL). Based on the detected hydrogen concentration and its rate of increase, the system executes the following three-level response: Level 1 response (early warning level).

[0125] Triggering conditions: The hydrogen concentration at any monitoring point exceeds 10% LEL but is below 25% LEL, or the rate of increase in concentration is less than 1% LEL / minute.

[0126] Perform the following actions: a triggers a yellow warning indicator and issues a notification on both the local control room and the cloud monitoring interface; b. Start or accelerate the explosion-proof ventilation fan in the area where the leak point is located, increasing the ventilation volume to 150%-200% of the rated air volume; The system remains in normal operation, ensuring uninterrupted power generation and charging services.

[0127] Level 2 response (control level).

[0128] Triggering conditions: The hydrogen concentration at any monitoring point reaches 25% LEL but is less than 50% LEL, or the concentration rise rate reaches or exceeds 1% LEL / minute.

[0129] Perform the following actions: Based on the first-level response, the warning will be upgraded to a local audible and visual alarm (rotating lighthouse, high-frequency buzzer). b. Close the upstream solenoid valve on the leak path to cut off the hydrogen supply to the faulty area (adopting a regional isolation strategy to ensure normal operation of non-faulty areas). The c system will smoothly reduce the output power to 50% of the rated power within 30 seconds, or switch to no-load standby mode. d sends an emergency alarm notification to the mobile phone of the maintenance personnel.

[0130] Level 3 response (emergency level).

[0131] Triggering conditions: The hydrogen concentration at any monitoring point reaches 50% LEL or above, or the concentration rises by more than 20% LEL within 1 minute.

[0132] Perform the following actions: Based on the Level 1 and Level 2 responses, a triggers a station-wide emergency broadcast and issues evacuation instructions; b. Close the main hydrogen valve to completely cut off the hydrogen supply to the entire system; c. Open the emergency vent valve to safely release the residual hydrogen in the pipeline and fuel cell stack to the outdoor high-altitude dilution device through a dedicated vent pipe. The venting process should be completed within 2-5 minutes. d sends an emergency shutdown command to the fuel cell power generation module. The system stops the entire power generation process within 10 seconds and executes electrical interlocking. e. Activate the fire sprinkler system or inert gas injection system in the accident area; f sends an alarm message to the fire department containing the location of the accident, the risk level, and the situation on site.

[0133] Through the above three-level response mechanism, this plan achieves full-chain hydrogen safety protection from early warning to emergency response: the first level focuses on ventilation and dilution without interrupting operations; the second level focuses on regional isolation and load reduction to control the spread of the situation; and the third level focuses on system-wide hydrogen cutoff, shutdown, and fire-fighting coordination to ensure the safety of personnel and equipment.

[0134] Example 2: A method for operating a hydrogen fuel cell supercharging station system includes the following steps: Step S1: Black boot.

[0135] When the system is in a shutdown state and receives a start command, the DC bus voltage is first established by the UPS (battery pack) or energy storage system to power the auxiliary systems of the hydrogen fuel cell power generation module (including air compressor, hydrogen circulation pump, cooling water pump, cooling fan, etc.). After the hydrogen fuel cell power generation module completes purging, preheating and hydrogen supply, the fuel cell starts to generate electricity and outputs power to the DC bus. At this time, the energy storage system switches from discharge mode to buffer mode.

[0136] Step S2: Power Allocation.

[0137] The main control module dynamically allocates the output power from the hydrogen fuel cell power generation module and the energy storage system to the DC bus based on the load demand of the charging module and the state of charge of the energy storage system. Specifically, the energy storage system is connected in parallel to the DC bus as a main buffer. The state of charge of the energy storage system is detected, and a power scheduling command for the hydrogen fuel cell power generation module is generated based on the deviation between the state of charge and the target range (e.g., 40%-60%). The hydrogen fuel cell power generation module executes the command according to a preset ramp rate, during which the energy storage system compensates for instantaneous power gaps. When a photovoltaic power generation system is configured, a "photovoltaic priority, energy storage buffer, fuel cell backup" allocation rule is adopted, and excess electrical energy is converted into hydrogen for storage through a water electrolysis hydrogen production system.

[0138] Step S3: Hydrogen supply switching.

[0139] When the multi-source hydrogen supply module needs to switch from the main hydrogen source to the backup hydrogen source, the main control module performs the following switching control: monitors the pressure of the main hydrogen source, and when the pressure drops to the first threshold, controls the hydrogen fuel cell power generation module to actively reduce the load to the switching power within 30 seconds, and opens the backup hydrogen source outlet valve in advance to precharge the backup pipeline; when the pressure drops to the second threshold (still higher than the minimum allowable inlet pressure of the fuel cell), the main pipeline valve is closed and the backup valve at the fuel cell stack inlet is opened at the same time, and the switching action takes less than 100 milliseconds; after the switching is completed, controls the hydrogen fuel cell power generation module to slowly restore power within 60 seconds; the power fluctuation during the switching process is compensated by the parallel energy storage system, and the power output fluctuation of the charging pile is controlled within 1%.

[0140] Step S4: Thermal Management.

[0141] The central thermal management controller independently controls the cooling power of the first and second independent heat dissipation circuits based on the temperature of the hydrogen fuel cell power generation module and the charging interface temperature of the charging module. Specifically, the first independent heat dissipation circuit controls the fuel cell operating temperature between 65-75°C, and the second independent heat dissipation circuit ensures that the charging interface temperature does not exceed 65°C. When the system is equipped with a third and fourth independent heat dissipation circuit, independent temperature control is performed on the power electronic devices and the energy storage system, respectively.

[0142] Step S5: Security Response.

[0143] The system monitors the hydrogen concentration in each area in real time and executes a three-level response based on the detected hydrogen concentration and the rate of increase: when the concentration exceeds 10% LEL but is below 25% LEL, the explosion-proof ventilation fan is started or accelerated, and the system maintains normal operation; when the concentration reaches 25% LEL but is below 50% LEL, the system upgrades to an audible and visual alarm, closes the upstream solenoid valve on the leak path, and reduces the system's output power to 50% of the rated power within 30 seconds; when the concentration reaches 50% LEL or above, the system triggers a station-wide emergency broadcast, closes the main hydrogen valve, opens the emergency vent valve, stops all power generation within 10 seconds, and activates fire-fighting linkage.

[0144] Step S6: Automatic shutdown and restart.

[0145] When the photovoltaic power generation is lower than the system's standby power consumption, all hydrogen source pressures are lower than the minimum operating pressure plus a safety margin, and the energy storage system's state of charge is lower than the shutdown protection threshold (typically 15%), the system performs an active shutdown: sequentially stopping external power supply, shutting down the hydrogen fuel cell power generation module and performing a safety purging, and reducing the power consumption of unnecessary equipment, so that the energy storage system's state of charge remains at the shutdown protection threshold and no longer decreases. After the system shuts down, the core monitoring module continuously monitors the wake-up source. When the hydrogen source pressure recovers, the photovoltaic voltage recovers, or a remote wake-up command is received, the black start procedure is re-executed.

[0146] By adopting a DC bus architecture of "fuel cell + energy storage battery" in parallel, coupled with multi-source hydrogen supply modules and a thermal management subsystem, and without a grid-connected interface to feed power to the external power grid, the system achieves true off-grid independent operation. This system does not rely on the municipal power grid for start-up power, frequency support, or power backup. It can be independently deployed and operated in areas without grid coverage, where grid expansion costs are extremely high, or where grid connection is not permitted (such as remote highway service areas, newly developed areas, islands, mines, and temporary emergency charging sites). This fundamentally solves the technical problems of traditional charging piles relying on grid power supply, exacerbating grid load during peak electricity consumption periods, and being unable to be deployed in areas without grid coverage.

[0147] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A hydrogen fuel cell supercharging pile system, characterized in that, include: At least one hydrogen fuel cell power generation module is connected to a DC bus via a first DC / DC converter; The energy storage system is connected to the DC bus via a second DC / DC converter; At least one charging module is connected to the DC bus via a third DC / DC converter for outputting charging power to the charging pile; The multi-source hydrogen supply module has its output end connected to the hydrogen inlet of the hydrogen fuel cell power generation module. The multi-source hydrogen supply module is equipped with at least two different types of hydrogen supply interfaces. The main control module is communicatively connected to the hydrogen fuel cell power generation module, energy storage system, and charging module, respectively. The main control module is configured to: use the energy storage system as the main buffer of the DC bus, calculate the target power of fuel cell scheduling based on the deviation between the state of charge of the energy storage system and the target interval, and control the fuel cell to execute scheduling instructions at a preset ramp rate, with the energy storage system compensating for the instantaneous power gap. The system does not have a grid-connected interface for feeding power to the external power grid and operates independently in off-grid mode.

2. The hydrogen fuel cell supercharging pile system as described in claim 1, characterized in that, The main control module is also configured to perform black start control, specifically: when the system is in a shutdown state, it establishes the DC bus voltage through the energy storage system or independent starting power supply and supplies power to the auxiliary system of the hydrogen fuel cell power generation module. After the hydrogen fuel cell power generation module starts, it outputs power to the DC bus, and the energy storage system switches to buffer mode.

3. The hydrogen fuel cell supercharging pile system as described in claim 1, characterized in that, The main control module is also configured to perform load response control, specifically: The energy storage system is connected in parallel to the DC bus as the main buffer. Based on the deviation between the state of charge of the energy storage system and the target range, and combined with the real-time output / input power of the energy storage system and the total load power of the system, the target power for fuel cell scheduling is calculated using the steady-state power balance formula. Based on the SOC partition scheduling logic and SOC differential power adjustment compensation, the scheduling target power is corrected; The hydrogen fuel cell power generation module is controlled to execute the modified scheduling instructions according to the preset ramp rate.

4. A hydrogen fuel cell supercharging pile system as described in claim 1, characterized in that, The main control module is also configured to perform hydrogen supply switching control, specifically: when the main hydrogen source pressure drops to a first threshold, the hydrogen fuel cell power generation module is controlled to actively reduce its load and pre-charge the backup hydrogen source pipeline; when the main hydrogen source pressure drops to a second threshold, the main pipeline and the backup pipeline are synchronously switched, wherein the second threshold is greater than the minimum allowable inlet pressure of the hydrogen fuel cell power generation module; after the switching is completed, the hydrogen fuel cell power generation module is controlled to restore its power; the power fluctuation during the switching process is compensated by the energy storage system.

5. A hydrogen fuel cell supercharging pile system as described in claim 1, characterized in that, The main control module is also configured to perform active shutdown protection, specifically: when the external energy input of the system is lower than the system standby power consumption, the pressure of all hydrogen sources is lower than the minimum working pressure plus the safety margin, and the state of charge of the energy storage system is lower than the shutdown protection threshold, active shutdown is performed, sequentially stopping the external power supply, shutting down the hydrogen fuel cell power generation module, reducing the power consumption of unnecessary equipment, and keeping the state of charge of the energy storage system at the shutdown protection threshold and no longer decreasing.

6. A hydrogen fuel cell supercharging pile system as described in claim 1, characterized in that, The multi-source hydrogen supply module has a main solenoid valve and a safety solenoid valve connected in series on the hydrogen supply pipeline to form a dual-redundant interlock control. A pressure sensor is installed between the two solenoid valves to monitor pressure changes between the valves. When an abnormal pressure fluctuation is detected, the system closes the two solenoid valves to cut off the hydrogen supply.

7. A hydrogen fuel cell supercharging pile system as described in claim 1, characterized in that, It also includes a photovoltaic power generation system and an electrolytic water hydrogen production system. The photovoltaic power generation system is connected to the DC bus through a fourth DC / DC converter, and the electrolytic water hydrogen production system is connected to the multi-source hydrogen supply module. When the photovoltaic power exceeds the charging load demand, the main control module controls the excess electrical energy to be converted into hydrogen through the electrolytic water hydrogen production system and stored in the hydrogen storage container of the multi-source hydrogen supply module.

8. A hydrogen fuel cell supercharging pile system as described in claim 1, characterized in that, The main control module is configured to: when the system is equipped with a photovoltaic power generation system, adopt the power allocation rule of "photovoltaic priority, energy storage buffer, and fuel cell backup"; when the system is not equipped with a photovoltaic power generation system, operate in "pure hydrogen plus energy storage" mode, with hydrogen supplied to the hydrogen fuel cell power generation module by the multi-source hydrogen supply module, the hydrogen fuel cell power generation module as the main power source supplying power to the DC bus, and the energy storage system used to balance instantaneous load fluctuations, provide black start energy, and compensate for power gaps during power switching.

9. A hydrogen fuel cell supercharging pile system as described in claim 1, characterized in that, It also includes a thermal management subsystem, which includes at least a first independent heat dissipation circuit and a second independent heat dissipation circuit. The first independent heat dissipation circuit is connected to the hydrogen fuel cell power generation module, the second independent heat dissipation circuit is connected to the charging interface of the charging module, the third independent heat dissipation circuit is connected to the power electronic devices, and the fourth independent heat dissipation circuit is connected to the energy storage system. The central thermal management controller independently adjusts the cooling power of each circuit according to the temperature sensor data of each circuit.

10. A method for operating a hydrogen fuel cell supercharging pile system according to any one of claims 1-9, characterized in that, Includes the following steps: The energy storage system or independent starting power supply establishes the DC bus voltage to power the auxiliary system of the hydrogen fuel cell power generation module. After the hydrogen fuel cell power generation module starts up, it outputs power to the DC bus. Based on the deviation between the state of charge of the energy storage system and the target range, a power scheduling command for the hydrogen fuel cell power generation module is generated. The hydrogen fuel cell power generation module executes the command according to the preset ramp rate, and the instantaneous power gap is compensated by the energy storage system during the process. The cooling power of the first independent heat dissipation circuit and the second independent heat dissipation circuit are independently controlled based on the temperature of the hydrogen fuel cell power generation module and the charging interface temperature of the charging module. Monitor the main hydrogen source pressure. When the pressure drops to the first threshold, control the hydrogen fuel cell power generation module to actively reduce the load and pre-charge the backup hydrogen source pipeline. When the pressure drops to the second threshold, perform synchronous switching between the main and backup pipelines. Monitor hydrogen concentration. When the concentration exceeds the first threshold, start ventilation. When the concentration exceeds the second threshold, cut off the hydrogen supply to the fault area and reduce the load. When the concentration exceeds the third threshold, cut off the hydrogen supply to the entire system and shut down.

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