Structure and method for controlling humidity of electric pile of fuel cell system

Abstract

The invention discloses an electric pile humidity control structure and method of a fuel cell system. The structure comprises an air compressor, a flow sensing module, a spraying and humidifying assembly, a humidity sensing module and an electric pile which are sequentially connected in series through an air pipeline, the spraying driving unit is connected with the spraying humidifying assembly through a spraying pipeline; the cooperative control unit is electrically connected with the air compressor, the flow sensing module, the spraying driving unit and the humidity sensing module through a CAN bus; the cooperative control unit generates a feedforward control instruction to adjust the rotating speed of the spray driving unit based on the flow data according to preset flow interval division and corresponding target rotating speed parameters of the spray driving unit; and based on the deviation between the humidity data and the target humidity, generating a feedback correction instruction to correct the rotating speed. By constructing an air compressor flow-humidifier spraying amount cooperative control system, real-time dynamic matching of the flow and the spraying amount is realized, the humidification uniformity is remarkably improved, the system energy consumption is reduced, and the performance degradation of a galvanic pile is effectively delayed.

Description

Technical Field

[0001] This invention relates to the field of air management technology for proton exchange membrane fuel cell systems, and particularly to a stack humidity control structure and method for a fuel cell system. Background Technology

[0002] Proton exchange membrane fuel cells (PEMFCs) have broad application prospects in fields such as automotive power due to their advantages such as high energy density and environmental friendliness. As a core component, the proton exchange membrane's proton conduction performance directly determines the stack's output efficiency and has stringent requirements for the humidity of the operating environment, needing to be maintained within a range of 30%-80%. When the humidity is below 30%, the membrane resistance increases by more than 50%, causing a sharp drop in the stack's output power; when the humidity is above 80%, the cathode gas diffusion layer is prone to flooding, reducing oxygen mass transfer efficiency by 12%-15%. Therefore, precise humidity control is crucial for the stable operation of a PEMFC system.

[0003] Existing PEMFC systems generally employ spray-type humidification, delivering compressed air to the humidifier via an air compressor, where a spray pump atomizes deionized water to achieve air humidification. However, this system suffers from control coupling issues and energy consumption drawbacks. The air compressor adjusts its speed based solely on load power input, neglecting the dynamic response capability of the humidification system. In automotive applications, sudden load changes can cause severe flow disturbances. The humidifier spray control relies on feedback from the fuel cell inlet humidity sensor, resulting in a 1-2 second response delay. Combined with the gas-liquid mixing time, this can easily lead to under-humidification or over-humidification issues. Under low load, the high-speed operation of the spray pump results in parasitic power accounting for 8%-10%, leading to significant energy waste. Furthermore, existing optimization methods using multiple sensors (such as dual humidity sensors) require pipeline reconfiguration, resulting in high modification costs, complex calibration, and increased failure rates, making it difficult to meet practical application requirements.

[0004] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art. Summary of the Invention

[0005] The purpose of this invention is to address the problems of uneven air humidification, high parasitic power loss, and accelerated performance degradation of fuel cell stacks in existing technologies by constructing a collaborative control system for air compressor flow rate and humidifier spray volume. By combining flow rate prediction and humidity correction, the system achieves real-time dynamic matching between air compressor flow rate and humidifier spray volume, thereby significantly improving humidification uniformity, reducing system energy consumption, and effectively delaying fuel cell stack performance degradation.

[0006] To achieve the above objectives, the present invention provides a stack humidity control structure for a fuel cell system, comprising: An air compressor, a flow sensing module, a spray humidification component, a humidity sensing module, and a fuel cell stack are connected in series via an air pipeline. The spray drive unit is connected to the spray humidification assembly via a spray pipe. The collaborative control unit is electrically connected to the air compressor, flow sensing module, spray drive unit, and humidity sensing module via a CAN bus. The collaborative control unit is used to receive flow data from the flow sensing module and humidity data from the humidity sensing module; based on the flow data, according to the preset flow range division and the corresponding target speed parameter of the spray drive unit, it generates a feedforward control command and sends it to the spray drive unit to adjust the speed; based on the deviation between the humidity data and the target humidity, it generates a feedback correction command and sends it to the spray drive unit to correct the speed.

[0007] Optionally, the flow sensing module is an insertable turbine flow sensor, the quick-connect fitting of the flow sensing module is connected to the quick-connect interface of the air compressor, and the insertion depth of the flow sensing module is 1 / 3 to 1 / 2 of the inner diameter of the air pipeline.

[0008] Optionally, the collaborative control unit includes a signal processing module and a logic decision module; the signal processing module is used to perform moving average filtering on the flow data; the logic decision module has a built-in association database containing multiple characteristic flow values ​​and their corresponding target rotation speed parameters of the spray drive unit.

[0009] Optionally, the collaborative control unit divides the filtered traffic data into three control intervals: low load interval, medium load interval, and high load interval, and uses hysteresis control for the interval thresholds.

[0010] Optionally, the humidity sensing module is a capacitive humidity sensor, and the distance between the humidity sensing module and the outlet of the spray humidification component is 140mm~150mm.

[0011] Optionally, before generating the speed adjustment command for the spray drive unit, the collaborative control unit is also used to determine the speed change rate of the air compressor; when the speed change rate is greater than 5000 r / min / s, the adjustment rate of the spray drive unit is reduced by 15% to 20%.

[0012] Optionally, the spray drive unit is a DC brushless pump that supports pulse width modulation signal speed regulation and avoids the resonance range of 1200r / min to 1500r / min during operation.

[0013] The present invention also provides a method for controlling the stack humidity of a fuel cell system, based on the above-described control structure, comprising the following steps: Step 1: Collect the air compressor speed and outlet flow, spray drive unit speed, fuel cell inlet humidity and power signals, and transmit them to the collaborative control unit after filtering. Step 2: Based on the power-flow mapping relationship of the fuel cell stack, the real-time flow is divided into low-load, medium-load, and high-load intervals, and hysteresis control is applied to the critical values ​​of the intervals. Step 3: The collaborative control unit outputs a corresponding pulse width modulation signal to adjust the rotation speed of the spray drive unit according to the current flow range; and corrects the rotation speed of the spray drive unit according to the deviation between the inlet humidity of the fuel cell stack and the target humidity.

[0014] Optionally, the lower limit of the target humidity satisfies the minimum humidity requirement of the proton exchange membrane under the current power of the fuel cell stack.

[0015] Optionally, in the high-load range, when the humidity at the fuel cell inlet is lower than the target humidity lower limit, additional speed compensation is applied.

[0016] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects: 1) By setting up a flow sensing module and a co-control unit to detect changes in the air compressor outlet flow rate in advance, and adjusting the speed of the spray drive unit in real time according to the preset flow range division and the target speed parameters of the spray drive unit. This feedforward control based on flow prediction overcomes the lag of relying solely on humidity feedback, enabling the spray volume (controlled by speed) to be quickly adjusted after changes in the air compressor flow rate. Combined with subsequent humidity correction, the feedforward-feedback synergy ensures uniform and stable humidity of the fuel cell inlet air, significantly reducing humidity deviation and effectively preventing performance degradation of the proton exchange membrane due to localized dryness or cathode flooding.

[0017] 2) Furthermore, the collaborative control unit can finely adjust the rotation speed of the spray drive unit according to the actual load demand (flow range), reduce the ineffective energy consumption of the spray drive unit under non-high load conditions, reduce its parasitic power ratio, and significantly improve the overall energy efficiency and economy of the fuel cell system.

[0018] 3) Furthermore, the present invention only requires the addition of a flow sensing module at the air compressor outlet of the existing PEMFC system and integration with the collaborative control unit. There is no need to reconstruct complex air pipelines or add multiple humidity sensors, resulting in low overall modification costs. It can be directly adapted to all vehicle and stationary fuel cell systems that are equipped with spray humidifiers, and has extremely high engineering applicability and promotion value. Attached Figure Description

[0019] Figure 1 This is a block diagram of the fuel cell stack humidity control structure of the present invention.

[0020] Figure 2 This is a flowchart of the fuel cell stack humidity control method of the present invention.

[0021] Attached image labels: 1. Air compressor; 2. Flow sensing module; 3. Spray humidification assembly; 4. Spray drive unit; 5. Fuel cell stack; 6. Cooperative control unit; 7. Humidity sensing module; 8. CAN bus; 9. Air pipeline; 10. Spray pipeline. Detailed Implementation

[0022] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed explanation of the fuel cell stack humidity control structure and method proposed in this invention. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, used only to facilitate and clarify the illustration of the embodiments of this invention. Please refer to the drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes to aid those skilled in the art and are not intended to limit the implementation conditions of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0023] As described in the background section, existing proton exchange membrane fuel cells use spray-type humidification, which suffers from control coupling problems and energy consumption defects. For example, the air compressor adjusts its speed based solely on the load power input, ignoring the dynamic response capability of the humidification system. In automotive applications, sudden load changes can cause severe flow disturbances. The humidifier spray control relies on feedback from the stack inlet humidity sensor, which has a 1-2 second response delay. Combined with the gas-liquid mixing time, this can easily lead to under-humidification or over-humidification. Under low load, the high-speed operation of the spray pump results in parasitic power accounting for 8%-10%, leading to significant energy waste.

[0024] To address the aforementioned issues, this invention employs a flow sensing module and a collaborative control unit to proactively detect changes in the air compressor outlet flow rate. Based on preset flow range divisions and target rotational speed parameters of the spray drive unit, the system adjusts the rotational speed of the spray drive unit in real time. This feedforward control, based on flow prediction, overcomes the lag inherent in relying solely on humidity feedback. It allows for rapid adjustment of the spray volume (controlled by rotational speed) after changes in the air compressor flow rate. Combined with subsequent humidity correction, this ensures uniform and stable humidity at the fuel cell inlet, significantly reducing humidity deviation. Consequently, it substantially improves humidification uniformity, reduces system energy consumption, and effectively slows down fuel cell performance degradation.

[0025] like Figure 1As shown, this invention provides a fuel cell stack humidity control structure for a fuel cell system. This structure includes an air compressor 1, a flow sensing module 2, a spray humidification assembly 3, a spray drive unit 4, a fuel cell stack 5, a collaborative control unit 6, a humidity sensing module 7, a CAN bus 8, an air pipeline 9, and a spray pipeline 10. The air pipeline 9 is connected in series with the air compressor 1, flow sensing module 2, spray humidification assembly 3, humidity sensing module 7, and fuel cell stack 5. The spray drive unit 4 is connected to the spray humidification assembly 3 via the spray pipeline 10. The collaborative control unit 6 is electrically connected to the air compressor 1, flow sensing module 2, spray drive unit 4, and humidity sensing module 7 via the CAN bus 8. A detailed description follows.

[0026] Air flows through air pipe 9, is compressed by air compressor 1, and then flows into flow sensing module 2. In some embodiments, air compressor 1 is a scroll compressor type with a rated flow rate of 200 m³ / h. 3 The compressor operates at a maximum speed of 60,000 r / min and has a G1 / 2 quick-connect interface at the outlet. It features flow signal output and can transmit flow data to the co-control unit 6 in real time, providing a basis for flow range determination. The flow sensing module 2 is an insertion-type turbine flow sensor, connected to the quick-connect interface of the air compressor 1 via a quick-connect fitting. The insertion depth is 1 / 3 to 1 / 2 of the inner diameter of the air pipe 9 (verified by CFD simulation to be within the stable flow velocity region, with turbulence intensity <5%, avoiding measurement deviations caused by uneven flow velocity within the pipe). It is used to measure the flow rate of compressed air passing through this location.

[0027] After air flows out from the flow sensing module 2, it flows sequentially through the spray humidification assembly 3 and the humidity sensing module 7. In some embodiments, the spray drive unit 4 is a DC brushless pump (model BLP-30) with a rated speed of 3000 r / min and a flow rate adjustment range of 0.5-2 L / min. It supports pulse width modulation (PWM) signal speed regulation (accuracy ±10 r / min, ensuring precise control of the spray volume). The spray drive unit 4 delivers deionized water to the spray humidification assembly 3 for atomization. During operation, it avoids the 1200-1500 r / min resonance range (at which point the vibration noise is <65 dB, reducing pump mechanical wear and system noise pollution). Before adjusting the speed, the cooperating control unit 6 needs to determine the rate of change of the air compressor 1's speed. When the rate of change of speed is >5000 r / min / s, the adjustment rate of the spray drive unit 4 is reduced by 15%~20% to avoid humidification imbalance caused by sudden changes in flow rate. The spray humidification assembly 3 includes a plate humidifier (effective humidification area 0.5 m²). 2The system (which ensures sufficient contact between compressed air and atomized water, improving humidification efficiency) and the atomizing nozzle (0.3mm orifice diameter, 60° atomization angle, enabling uniform water mist distribution and avoiding localized insufficient or excessive humidification) mix the atomized deionized water with the compressed air to complete air humidification. The humidity sensing module 7 is a capacitive humidity sensor with a measurement range of 0-100%RH and an accuracy of ±1%. Its distance from the outlet of the spray humidification component 3 is 140mm~150mm, effectively avoiding instantaneous fluctuations in the outlet humidity of the spray humidification component 3 while ensuring real-time monitoring of the humidity of the air entering the fuel cell stack 5, providing accurate feedback signals for subsequent humidity correction. The humidified air ultimately enters the fuel cell stack 5 to participate in the reaction.

[0028] During the above process, the flow sensing module 2 and the humidity sensing module 7 collect flow and humidity data in real time and upload them to the collaborative control unit 6 via the CAN bus 8. After processing the flow and humidity data according to the built-in algorithm, the collaborative control unit 6 generates control commands and transmits them to the air compressor 1 (adjusting speed / flow) and the spray drive unit 4 (adjusting speed / spray volume) via the CAN bus 8.

[0029] The collaborative control unit 6 is built on an STM32F407 microprocessor (168MHz) and includes a built-in CAN communication module (250kbps) and signal processing module. The collaborative control unit 6 establishes electrical connections with the air compressor 1, flow sensing module 2, spray drive unit 4, and humidity sensing module 7. The signal processing module processes the 4-20mA signal output from the flow sensing module 2 using a 12-bit AD converter, and then optimizes the data using a moving average filtering algorithm (window size N=5, used to suppress high-frequency noise >100Hz to avoid misjudgments caused by instantaneous flow fluctuations). It also includes a built-in flow-spray volume correlation database containing values ​​of 20, 40, 50, 60, 80, 100, 120, 140, 150, 160, 180, and 200mA. 3 The system contains 12 sets of characteristic flow rate values ​​corresponding to the target rotational speed parameters of the spray drive unit 4, with a speed adjustment rate of 50 r / min. The logic decision module includes operating range division, speed adjustment, and exception handling algorithms (code size < 10KB, low microprocessor resource consumption, ensuring real-time output of control commands). Data interaction between modules is achieved via CAN bus 8, with a control command transmission delay of < 100ms, meeting the requirements for rapid response under dynamic operating conditions.

[0030] In this embodiment, an experimental system is constructed using a 60kW automotive PEMFC system as a fixed test platform. The core equipment parameters of its fuel cell stack humidity control structure are as follows: 1) Air compressor: Scroll type, rated flow 180m³ / h 3 / h, maximum speed 60000r / min, outlet pressure fixed at 0.14MPa (taken as the midpoint of the original range of 0.12-0.15MPa, to meet the normal pressure requirements of automotive applications).

[0031] 2) Flow sensing module: Employs an insertion turbine flow sensor with a range of 0-200m. 3 / h, measurement accuracy ±2%, response time 0.5s, connects to the quick-connect interface of the air compressor through G1 / 2 specification quick-connect coupling, the insertion depth is 1 / 2 of the inner diameter of the air pipeline (30mm), i.e. 15mm.

[0032] 3) Spray humidification unit: A plate humidifier is selected, with an effective humidification area of ​​0.4m². 2 It is equipped with an atomizing nozzle with an orifice diameter of 0.3mm, an atomization angle of 60°, and a fixed atomized particle diameter of 8μm (taking the middle value of the original range of 5-10μm to ensure uniform mixing of water mist and air).

[0033] 4) Cooperative control unit: Based on a microprocessor with a main frequency of 168MHz, configured with a 12-bit AD conversion module, a fixed CAN communication rate of 250kbps, and code size controlled at 8KB (<10KB upper limit).

[0034] 5) Fuel cell stack: Utilizes a 200-cell series connection structure, with each cell having an effective area of ​​200 cm². 2 The rated voltage is 72V and the rated power is 60kW. The operating temperature is kept constant at 60℃ during the experiment (the commonly used operating condition value within the original range of 50-70℃ is taken to avoid temperature fluctuations from interfering with the experimental results).

[0035] 6) Humidity sensing module: It adopts a capacitive humidity sensor with a measurement range of 0-100%RH and an accuracy of ±1%. The distance between the sensor and the outlet of the spray humidification component is 150mm.

[0036] 7) Spray drive unit: adopts DC brushless pump (model BLP-30), rated speed 3000r / min, flow rate adjustment range 0.5-2L / min, supports PWM signal speed regulation, accuracy ±10r / min.

[0037] This invention also provides a method for controlling the stack humidity of a fuel cell system, implemented based on the aforementioned control structure, such as... Figure 2 As shown, it includes the following steps: Step 1: Collect the air compressor speed and outlet flow, spray drive unit speed, fuel cell inlet humidity and power signals, and transmit them to the collaborative control unit after filtering.

[0038] The flow sensing module collects the air compressor outlet flow and speed (resolution 100r / min), spray drive unit speed (resolution 10r / min), fuel cell inlet humidity (5Hz sampling), and fuel cell power signal (resolution 1kW) at a frequency of 10Hz. After processing by a moving average filtering algorithm (window size N = 5, suppressing high-frequency noise with frequency > 100Hz), the data is transmitted to the collaborative control unit via CAN bus (delay < 100ms) to ensure the comprehensiveness and timeliness of data acquisition.

[0039] Step 2: Based on the power-flow mapping relationship of the fuel cell stack, the real-time flow is divided into low-load, medium-load, and high-load intervals, and hysteresis control is applied to the critical values ​​of the intervals.

[0040] The flow rate range division and judgment are based on the power-flow mapping relationship established by 100 sets of operating condition experiments (temperature 50-70℃, hydrogen pressure 0.12MPa). The filtered flow rate is divided into three control ranges: low load range (flow rate < 50m³ / h). 3 / h, corresponding to power <20kW), medium load range (50m) 3 / h≤flow rate<120m 3 / h, corresponding to a power of 20-60kW), high load range (flow rate ≥120m³ / ...). 3 / h, corresponding to a power >60kW); and the critical value of the interval (48-52m) 3 / h, 118-122m 3 / h) uses hysteresis control (hysteresis value 2m) 3 / h), to avoid mechanical wear caused by frequent adjustments to the spray drive unit.

[0041] Step 3: The collaborative control unit outputs a corresponding pulse width modulation signal to adjust the rotation speed of the spray drive unit according to the current flow range; and corrects the rotation speed of the spray drive unit according to the deviation between the inlet humidity of the fuel cell stack and the target humidity.

[0042] The spray drive unit outputs a pulse width modulation (PWM) signal to adjust its rotational speed according to the flow rate range, with an adjustment response time ≤0.3s. The target rotational speed of the spray drive unit in the low-load range is = current rotational speed × 0.75 (adjustment rate 50 r / s); the target rotational speed in the medium-load range is = current rotational speed × 0.95 (adjustment rate 80 r / s); and the target rotational speed in the high-load range is = current rotational speed × 1.1 (adjustment rate 100 r / s). The lower limit of the target humidity meets the minimum humidity requirement of the proton exchange membrane under the current power of the fuel cell stack. When the flow rate in the high-load range is ≥150 m³ / s for 10s... 3When the flow rate is less than 10% of the dynamic target humidity level at the fuel cell inlet, an additional 8% speed compensation is applied (the compensated speed does not exceed 3000 r / min) until the flow rate is less than 140 m³ / h. 3 / h and will be deactivated when the humidity returns to the target range.

[0043] The operation process of the fuel cell system of the present invention is as follows: (1) Start-up phase (0-60s): The air compressor runs at the base speed (20000r / min), and the control unit adjusts the speed of the spray drive unit to 0.75 times the current value and controls the relative humidity between 55% and 60% through humidity feedback correction; (2) Steady-state operation phase: The spray drive unit maintains the corresponding rotation speed within the range, and makes fine adjustments every 500ms to ensure that the humidity deviation is <±3%; (3) Dynamic load stage: The coordinated control unit completes the speed adjustment within 0.3s to match the flow rate change in advance; (4) Exception handling phase: Switch to fault-tolerant mode to ensure safety; (5) Shutdown phase: The spray drive unit speed is reduced to 0 synchronously with the air compressor speed to avoid water accumulation and blockage of the nozzles.

[0044] In summary, this invention, by setting up a flow sensing module and a collaborative control unit to detect changes in the air compressor outlet flow in advance, and adjusting the speed of the spray drive unit in real time according to the preset flow range division and the target speed parameters of the spray drive unit, overcomes the lag of relying solely on humidity feedback. This allows the spray volume to be quickly adjusted after changes in the air compressor flow. Combined with subsequent humidity correction, the feedforward-feedback collaboration ensures uniform and stable humidity of the fuel cell inlet air, significantly reducing humidity deviation, thereby significantly improving humidification uniformity, reducing system energy consumption, and effectively delaying fuel cell performance degradation.

[0045] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0046] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A stack humidity control structure for a fuel cell system, characterized in that, Include: An air compressor, a flow sensing module, a spray humidification component, a humidity sensing module, and a fuel cell stack are connected in series via an air pipeline. The spray drive unit is connected to the spray humidification assembly via a spray pipe. The collaborative control unit is electrically connected to the air compressor, flow sensing module, spray drive unit, and humidity sensing module via a CAN bus. The collaborative control unit is used to receive flow data from the flow sensing module and humidity data from the humidity sensing module; based on the flow data, according to the preset flow range division and the corresponding target speed parameter of the spray drive unit, it generates a feedforward control command and sends it to the spray drive unit to adjust the speed; based on the deviation between the humidity data and the target humidity, it generates a feedback correction command and sends it to the spray drive unit to correct the speed.

2. The fuel cell stack humidity control structure of the fuel cell system as described in claim 1, characterized in that, The flow sensing module is an insertion turbine flow sensor. The quick-connect fitting of the flow sensing module is connected to the quick-connect interface of the air compressor. The insertion depth of the flow sensing module is 1 / 3 to 1 / 2 of the inner diameter of the air pipeline.

3. The fuel cell stack humidity control structure of the fuel cell system as described in claim 1, characterized in that, The collaborative control unit includes a signal processing module and a logic decision module; the signal processing module is used to perform moving average filtering on the flow data; the logic decision module has a built-in association database containing multiple characteristic flow values ​​and their corresponding target rotation speed parameters of the spray drive unit.

4. The fuel cell stack humidity control structure of the fuel cell system as described in claim 3, characterized in that, The collaborative control unit divides the filtered traffic data into three control intervals: low load interval, medium load interval, and high load interval, and uses hysteresis control for the interval thresholds.

5. The fuel cell stack humidity control structure of the fuel cell system as described in claim 1, characterized in that, The humidity sensing module is a capacitive humidity sensor, and the distance between the humidity sensing module and the outlet of the spray humidification component is 140mm~150mm.

6. The fuel cell stack humidity control structure of the fuel cell system as described in claim 1, characterized in that, Before generating the speed adjustment command for the spray drive unit, the collaborative control unit is also used to determine the speed change rate of the air compressor; when the speed change rate is greater than 5000 r / min / s, the adjustment rate of the spray drive unit is reduced by 15% to 20%.

7. The fuel cell stack humidity control structure of the fuel cell system as described in claim 1, characterized in that, The spray drive unit is a DC brushless pump that supports pulse width modulation signal speed regulation and avoids the resonance range of 1200r / min to 1500r / min during operation.

8. A method for controlling the stack humidity of a fuel cell system, implemented based on the control structure described in any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Collect the air compressor speed and outlet flow, spray drive unit speed, fuel cell inlet humidity and power signals, and transmit them to the collaborative control unit after filtering. Step 2: Based on the power-flow mapping relationship of the fuel cell stack, the real-time flow is divided into low-load, medium-load, and high-load intervals, and hysteresis control is applied to the critical values ​​of the intervals. Step 3: The collaborative control unit outputs a corresponding pulse width modulation signal to adjust the rotation speed of the spray drive unit according to the current flow range; and corrects the rotation speed of the spray drive unit according to the deviation between the inlet humidity of the fuel cell stack and the target humidity.

9. The fuel cell stack humidity control method for a fuel cell system as described in claim 8, characterized in that, The lower limit of the target humidity satisfies the minimum humidity requirement of the proton exchange membrane under the current power of the fuel cell stack.

10. The fuel cell stack humidity control method for a fuel cell system as described in claim 9, characterized in that, Within the high-load range, when the humidity at the fuel cell inlet is lower than the target humidity lower limit, additional speed compensation is applied.

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