A SOFC multi-path air flow control method, air supply system and power generation system
Patent Information
- Application Number
- CN202611114461.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-27
- Publication Date
- 2026-09-15
AI Technical Summary
针对现有技术中多支路SOFC空气旁通流量控制方法中多条空气路耦合程度很高，需要鼓风机频繁调速，导致系统稳定性差的问题，本发明提供一种SOFC多路空气流量控制方法、空气供应系统及发电系统，能够实现双重闭环控制，降低鼓风机调速频次，提高系统稳定性
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Figure CN122756291A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of air supply technology for solid oxide fuel cells, specifically to a multi-channel air flow control method, air supply system, and power generation system for SOFCs. Background Technology
[0002] Solid oxide fuel cells (SOFCs) are a type of efficient and clean new energy power generation device with an operating temperature of up to 700℃~1000℃. By directly converting the chemical energy in natural gas into electrical energy, they have advantages such as high power generation efficiency, low emissions, and flexible modular deployment. They are widely used in distributed power generation, off-grid power supply and other scenarios, and are especially suitable as the baseload power source for large-scale data centers.
[0003] The stable operation of SOFC systems is highly dependent on the stability and precision of the air supply. As the cathode oxidant, the flow distribution of air directly affects the electrochemical reaction efficiency, temperature field distribution, and lifespan of the battery. To adapt to the air requirements of SOFC under different load conditions, multiple air bypass branches are usually set in the main air circuit. By regulating the flow of the bypass branches, the flow rate and temperature of the incoming air can be flexibly controlled. At the same time, when the system state changes or the temperature is too high, the bypass cold air can be used to cool down and maintain the system temperature balance.
[0004] Currently, the control methods for air bypass flow in multi-branch SOFCs are mainly divided into three types: total flow demand control, constant pressure control, and main air flow control.
[0005] Total flow demand control adjusts the blower speed by regulating the total flow demand of the main air path and bypass branches. However, this method has a high degree of coupling between multiple air paths, resulting in an unbalanced distribution of air flow across multiple air paths. Frequent adjustments to the blower speed and regulating valve opening lead to unstable air supply, severe system oscillations, and even non-convergence.
[0006] Constant pressure control indirectly controls the bypass flow by detecting the pressure in the main air pipe and adjusting the blower speed. However, this method requires additional pressure sensors, which increases system cost and wiring complexity. Furthermore, the coupling relationship between pressure and flow can easily lead to adjustment lag, affecting control accuracy.
[0007] Main air flow control uses the main air flow as feedback to adjust the blower speed. Although this simplifies the control logic, there is a serious "air competition" phenomenon between the multiple bypass branches. The bypass flow interferes with each other, and when the bypass load fluctuates, even a small change in the main air flow will cause the blower to frequently adjust its speed. This results in poor system stability and problems such as the bypass valve being fully open or fully closed, or losing its adjustment margin. It cannot adapt to the operating conditions of SOFC with frequent load changes. In severe cases, it will affect the stability of the battery electrochemical reaction, reduce the system's power generation efficiency and service life.
[0008] Therefore, there is an urgent need for a SOFC air bypass flow control method that can solve the above-mentioned technical defects and achieve independent and precise control of multiple bypass flow rates, system stability and reliability, and energy efficiency. Summary of the Invention
[0009] 1. The problem to be solved To address the problem that existing multi-branch SOFC air bypass flow control methods have a high degree of coupling between multiple air paths, requiring frequent blower speed adjustments and resulting in poor system stability, this invention provides a multi-path SOFC air flow control method, an air supply system, and a power generation system. This method enables dual closed-loop control, reduces the frequency of blower speed adjustments, and improves system stability.
[0010] 2. Technical Solution The first aspect of this invention provides a method for controlling multiple airflow channels in an SOFC (Self-Containing Flow Control) system, comprising the following steps: S1. System initialization and parameter setting: Calculate and set the target flow rate of the main air circuit and multiple air bypass circuits; set the optimal opening range of the electric regulating valves on each air circuit; S2. Independent flow control for each air path: Real-time acquisition of the actual flow of each air path, comparison of the actual flow of each air path with the target flow, and control and adjust the opening of the electric regulating valve of the corresponding air path according to the comparison result, so that the actual flow of each air path approaches the target flow, thereby realizing independent closed-loop control of the flow of multiple air paths. S3. Extract the maximum valve position value of each air path: collect the actual valve position feedback value of the electric regulating valve in each air path in real time, and calculate the maximum value among all actual valve position feedback values. S4. Adjust the blower speed based on the maximum actual valve position feedback value: Compare the maximum actual valve position feedback value obtained in step S3 with the optimal opening range of the electric regulating valve set in step S1, and control the blower speed according to the comparison result so that the maximum actual valve position feedback value is stable within the optimal opening range. S5. Repeat steps S2 to S4 to form a closed-loop control.
[0011] As a preferred embodiment of the present invention, in step S4: If the maximum actual valve position feedback value is greater than the upper limit of the optimal opening range, increase the blower speed and increase the total air supply so that the maximum actual valve position feedback value gradually decreases to the optimal opening range. If the maximum actual valve position feedback value is less than the lower limit of the optimal opening range, reduce the blower speed and reduce the total air supply so that the maximum actual valve position feedback value gradually rises to the optimal opening range. If the maximum actual valve position feedback value is within the optimal opening range, the blower will maintain its current speed to avoid frequent speed adjustments that could cause system oscillations.
[0012] As a preferred embodiment of the present invention, a target valve position for the blower is set within the optimal opening range, and the target valve position for the blower approaches the middle value of the optimal opening range; when the maximum actual valve position feedback value is greater than the upper limit of the optimal opening range or less than the lower limit of the optimal opening range, the blower speed is adjusted so that the maximum actual valve position feedback value gradually recovers to the target valve position for the blower, thereby increasing the adjustment margin of the electric regulating valve and reducing the frequency of blower adjustment.
[0013] As a preferred embodiment of the present invention, in step S1, the optimal opening range is 50%-85%, and the target valve position of the fan is 70%.
[0014] As a preferred embodiment of the present invention, in step S2, after comparing the actual flow rate of each air path with the target flow rate, feedforward compensation is first performed according to the characteristic curve of the electric regulating valve to quickly respond to the valve opening required for the target flow rate. Then, based on the comparison result, the opening of the electric regulating valve of each air path is finely adjusted by the feedback control of the independent flow PID controller of each air path to achieve independent closed-loop control and rapid response of the flow of multiple air paths. Preferably, in step S4, after comparing the maximum actual valve position feedback value with the optimal opening range, when the blower speed needs to be adjusted, the system performs feedforward compensation based on the characteristic curve of the blower, responds quickly in advance to the vicinity of the required blower speed, and then fine-tunes the blower speed through feedback control of the blower PID controller.
[0015] As a preferred embodiment of the present invention, when the SOFC system load changes, the target flow rate of the corresponding air path is updated in real time, and the system repeats steps S1 to S5 to achieve dynamic adaptation of the flow rate of each air path. Preferably, in step S1, the minimum operating speed and the maximum operating speed of the fan are set.
[0016] As a preferred embodiment of the present invention, in step S2, the actual flow signals of each air path are soft-filtered in real time to filter signal noise under high temperature environment, so as to improve the detection accuracy of actual flow.
[0017] A second aspect of the present invention provides an air supply system for implementing the above-mentioned SOFC multi-channel air flow control method, including a blower, the blower being connected to the cathode inlet of the fuel cell stack via an air main line, and multiple air bypasses being connected in parallel on the air main line; flow sensors and electric regulating valves are provided on the air main line and each bypass line, and the electric regulating valves are equipped with valve position feedback modules.
[0018] As a preferred embodiment of the present invention, the air bypass includes at least a first-stage bypass and a final-stage bypass; The outlet of the first-stage bypass is connected to the cathode inlet of the fuel cell stack, and the outlet of the last-stage bypass is connected to the cathode outlet of the fuel cell stack.
[0019] A third aspect of the present invention provides a power generation system, including a fuel cell stack and the aforementioned air supply system; A fuel cell stack includes one or more fuel cell stack groups; When multiple fuel cell stacks are set up, the cathode outlet of the upper-level fuel cell stack is connected to the cathode inlet of the lower-level fuel cell stack, and the air supply system also includes one or more intermediate bypasses. The intermediate bypass is used to supply air to the cathode exhaust gas supply pipeline of the adjacent fuel cell stack to adjust the cathode inlet temperature of the corresponding fuel cell stack cathode. The outlet of the first-stage bypass is connected to the cathode inlet of the first-stage fuel cell stack, and the outlet of the last-stage bypass is connected to the cathode outlet of the last-stage fuel cell stack.
[0020] 3. Beneficial effects Compared with the prior art, the beneficial effects of the present invention are as follows: The SOFC multi-channel airflow control method in this invention features dual closed-loop control: a large closed-loop control of the blower to regulate the total airflow, and an independent closed-loop control of each air channel to regulate the distribution ratio of the total airflow in each air channel. This is a control strategy that prioritizes the independent distribution of airflow in each air channel and provides a fallback for regulating the total blower flow. While meeting the airflow requirements of each air channel, it significantly reduces the frequency of blower speed regulation and improves system stability.
[0021] By collecting the actual flow rate of each air path in real time and comparing it with the target flow rate, the opening of the electric regulating valve of the corresponding air path is controlled and adjusted according to the comparison result. This makes the actual flow rate of each air path approach the target flow rate, decoupling the flow rates of multiple air paths and achieving independent closed-loop control of the flow rates of multiple air paths. Based on the independent flow control of each air path, when the flow rate of each air path fluctuates, the blower speed is not necessarily adjusted. Instead, the maximum actual valve position feedback value is compared with the optimal opening range of the electric regulating valve. The blower speed is adjusted only when the maximum actual valve position feedback value exceeds the optimal opening range; otherwise, the blower speed is not adjusted, reducing the frequency of blower speed adjustment and improving system stability. Attached Figure Description
[0022] Figure 1 This is a flowchart illustrating the SOFC multi-channel airflow control method of the present invention; Figure 2 This is a schematic diagram of the process for independent flow control of each air path in this invention; Figure 3 This is a schematic diagram illustrating the process of extracting the maximum valve position value of each air path and adjusting the blower speed based on the maximum actual valve position feedback value in this invention. Figure 4 This is a logic block diagram of the optimal opening interval determination module in this invention; Figure 5 This is a schematic diagram of the power generation system in this invention, showing a dual-stack assembly with the stack anodes connected in parallel; Figure 6 This is a schematic diagram of the power generation system in this invention, which consists of multiple fuel cell stacks with the anodes of the stacks connected in series.
[0023] Explanation of the labels in the diagram: 1-Water tank, 2-Water pump, 3-Heat exchanger, 4-Reformer, 5-Burner, 6-Blower, 7-Flow sensor, 8-Electric regulating valve. Detailed Implementation
[0024] To further understand the content of this invention, a detailed description of the invention will be provided in conjunction with the accompanying drawings and embodiments.
[0025] The structures, proportions, and sizes illustrated in the accompanying drawings are merely for illustrative purposes and to aid those skilled in the art in understanding and reading the invention. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.
[0026] Example 1 like Figure 5 As shown, this embodiment provides an air supply system, including a blower 6. The blower 6 is connected to the cathode inlet of the fuel cell stack via a main air path, and multiple air bypasses are connected in parallel on the main air path. After the blower 6 is started, it can simultaneously blow air into the main air path and the multiple air bypasses.
[0027] Flow sensors 7 and electric regulating valves 8 are installed on the main air path and each bypass path. The flow sensors 7 can detect the air flow in each air path in real time, and the electric regulating valves 8 have a built-in valve position feedback module that can provide real-time feedback on the opening degree of the electric regulating valves 8. Preferably, the flow sensors 7 are located upstream of the electric regulating valves 8 along the air flow direction to improve the accuracy of the flow sensors 7.
[0028] The air bypass includes at least a first-stage bypass and a last-stage bypass. The outlet of the first-stage bypass is connected to the cathode inlet of the fuel cell stack and is used to regulate the inlet temperature of the fuel cell stack cathode. The outlet of the last-stage bypass is connected to the cathode outlet of the fuel cell stack, i.e., the air inlet of the burner 5, to supplement the air flow of the burner 5 and regulate the outlet exhaust gas temperature of the downstream burner 5.
[0029] like Figure 6 As shown, when there are multiple fuel cell stacks, the cathode outlet of the previous stage fuel cell stack is connected to the cathode inlet of the next stage fuel cell stack. In this case, the outlet of the first-stage bypass is connected to the cathode inlet of the first-stage fuel cell stack, and the outlet of the last-stage bypass is connected to the cathode outlet of the last-stage fuel cell stack. Furthermore, the air supply system also includes one or more intermediate bypasses, the number of which is one less than the number of fuel cell stacks. The outlet of each intermediate bypass is connected to the cathode exhaust gas supply pipe of the adjacent fuel cell stack, supplementing the airflow to the next stage fuel cell stack and regulating the air inlet temperature of the next stage fuel cell stack.
[0030] The complete power generation system also includes gas and water delivery sections. Water pump 2 draws water from water tank 1, which then passes through heat exchanger 3 and reformer 4 before being delivered to the fuel cell stack anode. Gas flows through flow sensor 7, merges with water before heat exchanger 3, and then moves together towards the fuel cell stack anode. Anode and cathode exhaust gases generated at the fuel cell stack anode and cathode are fed into burner 5. The high-temperature flue gas generated by combustion is sequentially fed to the hot side of reformer 4 and heat exchanger 3, providing heat for the reforming reaction and water evaporation. A heat exchanger 3 is also installed in the main air path to preheat the air flowing towards the fuel cell stack cathode, ensuring it meets the cathode's temperature requirements.
[0031] When setting up multiple fuel cell stacks, the anodes of the multiple fuel cell stacks can be connected in parallel, such as... Figure 5 As shown; they can also be connected in series, such as Figure 6 As shown.
[0032] Example 2 This embodiment provides a method for controlling multiple airflow channels in an SOFC system, such as... Figure 1 As shown, it includes the following steps: S1. System Initialization and Parameter Setting: Start the air supply system and initialize the blower 6, each electric regulating valve 8, and each flow sensor 7 to ensure that all equipment is working properly.
[0033] Calculate the target flow rates SV1~SV of the main air path and multiple air bypasses. n (n≥3, n is the number of air paths), set the optimal opening range of the electric regulating valve 8 on each air path to 50%~85%, set the minimum speed Fan_n_Min and the maximum operating speed Fan_n_Max of the blower 6, set the characteristic curves of the variable frequency blower 6 and the electric regulating valve 8 calibrated by the supplier, and set the parameters of the flow PID controller and the blower PID controller.
[0034] The optimal opening range for each of the above-mentioned electric regulating valves 8 is consistent and is independent of the pipe diameter of the electric regulating valve 8. The pipe diameter of the electric regulating valve 8 can be selected according to the actual needs of the system. Since the air paths are interconnected, each electric regulating valve 8 is in a dynamic adjustment state. The optimal opening range is selected as the condition for blower adjustment based on the largest opening of the electric regulating valve 8 in the air path.
[0035] S2. Independent flow control for each air path: like Figure 2 As shown, the actual flow rates PV1~PV in each air path are collected in real time by the flow sensors 7 on each air path. n And the actual flow rates PV1~PV of each air path n With target flow SV1~SV nBy comparison, the characteristic curve of the electric regulating valve 8 is used as feedforward control, with open-loop predictive compensation to activate the electric regulating valve 8 in advance, quickly responding to the valve opening degree required for the target flow rate, avoiding large disturbances in the system control, and significantly reducing the burden on the flow PID controller; then, each air path's independent flow PID controller performs calculations (the parameters of the flow PID controller are determined based on empirical tuning), outputting the corresponding valve position control signals OP1~OP1. n This allows for fine-tuning of the opening of the electric regulating valve 8 in each air path, ensuring that the actual flow rate in each air path tracks the target flow rate, thus achieving independent closed-loop control and rapid response for multiple air path flow rates. It is understandable that independent closed-loop control of multiple air path flow rates can be achieved even without feedforward regulation.
[0036] Actual flow tracking target flow means that when the actual flow is greater than the target flow, the opening of the electric regulating valve 8 on the corresponding air path is reduced, so that the actual flow in the air path decreases and gradually approaches the target flow; when the actual flow is less than the target flow, the opening of the electric regulating valve 8 on the corresponding air path is increased, so that the actual flow in the air path increases and gradually approaches the target flow.
[0037] S3. Extract the maximum valve position value for each air path: like Figure 3 As shown, based on the valve position feedback module built into the electric regulating valve 8 of each air path, the actual valve position feedback values FB1~FB of the electric regulating valve 8 in each air path are collected in real time. n The maximum value MAX_OP among all actual valve position feedback values is calculated by comparison, that is, MAX_OP = MAX(FB1, FB2, ..., FB). n The maximum value MAX_OP represents the bypass branch that currently needs the most airflow and is the most difficult to regulate; its valve position directly reflects the total air demand of the system.
[0038] S4. Adjust the speed of blower 6 based on the maximum actual valve position feedback value: like Figure 3 As shown, the maximum actual valve position feedback value MAX_OP obtained in step S3 is compared with the optimal opening range of the electric regulating valve 8 set in step S1. If the maximum actual valve position feedback value MAX_OP exceeds the optimal opening range, the speed of the blower 6 needs to be adjusted.
[0039] When the speed of blower 6 needs adjustment, the system uses the characteristic curve of blower 6 as feedforward control, employing open-loop predictive compensation. Based on the required airflow, it pre-adjusts the speed of blower 6 to near the desired speed. Then, the blower PID controller performs calculations and outputs a speed control signal to adjust the speed of blower 6, ensuring the maximum actual valve position feedback value MAX_OP remains stable within the optimal opening range. This allows for rapid response to the speed requirements of blower 6, reducing the burden on the blower PID controller, minimizing large disturbances and control overshoot, and making the control of blower 6 more stable.
[0040] The logic of the optimal opening interval determination module is as follows: Figure 4 As shown, in the initialization state (Lock), PID control enable (PidEn) = 0 (disabled), speed regulation state (SpeedLock) = 0 (holding state), and the timer (ct) is not running. When the maximum actual valve position feedback value MAX_OP exceeds the optimal opening range limit, it enters the trigger state, speed regulation starts, PID control enable (PidEn) = 1, speed regulation state (SpeedLock) = 1 for speed regulation, and the timeout timer (ctTimeOut) works to avoid excessive adjustment time. When the maximum actual valve position feedback value MAX_OP approaches the target valve position and is within the allowable error range (dt_Op), it enters the stable state. At this time, PID control enable (PidEn) = 1, speed regulation state (SpeedLock) = 1 for speed regulation, and the stabilization timer (ctStable) works. After stabilizing within the allowable error range for a period of time (tiStable), the system is considered stable and enters the lock state. PID control enable (PidEn) = 0 indicates disabled, and SpeedLock = 0 indicates hold mode, with the timer (ct) not counting. During PID enable, the fan characteristic curve is used as feedforward control, with open-loop predictive compensation. The fan speed is adjusted in advance according to the required air volume, reducing the burden on the PID controller and avoiding large disturbances. The PID controller then performs calculations and outputs a speed control signal to adjust the blower speed, ensuring that the maximum actual valve position feedback value MAX_OP remains stable within the optimal opening range.
[0041] The specific adjustment logic of blower 6 is as follows: If the maximum actual valve position feedback value MAX_OP is greater than the upper limit of the optimal opening range, i.e. MAX_OP > 85%, it indicates that the current total air supply of the system is insufficient. The electric regulating valve 8 of the most strained air path is almost fully open, and the adjustment margin is insufficient. The fan PID controller needs to output an increase speed signal, use the fan characteristic curve as feedforward control, and perform open-loop predictive compensation to adjust the fan speed in advance according to the required air volume, reduce the burden on the PID controller, avoid large disturbances, and then perform calculations through the PID controller to output a speed control signal to increase the total air supply, so that the maximum actual valve position feedback value MAX_OP gradually decreases to the optimal opening range.
[0042] If the maximum actual valve position feedback value MAX_OP is less than the lower limit of the optimal opening range, i.e. MAX_OP < 50%, it indicates that the current total air supply of the system is excessive, the opening of the electric regulating valve 8 in all air paths is small, the fan PID controller outputs a speed reduction signal to control the blower 6 to reduce its operating speed (the control principle is the same as above), reduce the total air supply, and make the maximum actual valve position feedback value MAX_OP gradually rise to the optimal opening range.
[0043] If the maximum actual valve position feedback value MAX_OP is within the optimal opening range, i.e. 50%≤MAX_OP≤85%, it indicates that the current total air supply of the system matches the total demand of the bypass branch, and all bypass branches have sufficient adjustment margin. At this time, the fan PID controller stops adjusting, and the blower 6 maintains its current speed to avoid frequent speed adjustments that could cause system oscillation.
[0044] S5. Repeat steps S2-S4 to form a closed-loop control: The system collects the actual flow rate of each air path and the actual valve position feedback value of the electric regulating valve 8 on each air path in real time, dynamically updates the maximum actual valve position feedback value MAX_OP, and continuously adjusts the opening degree of the electric regulating valve 8 and the speed of the blower 6 to form a closed-loop control.
[0045] For example, when the operating speed of blower 6 increases, it indicates a gradual increase in air supply. The opening of all electrically controlled regulating valves 8 should gradually decrease to maintain the actual flow rate of each air path close to the target flow rate. During the adjustment of the opening of the electrically controlled regulating valves 8, the maximum actual valve position feedback value MAX_OP is acquired in real time. The opening of the electrically controlled regulating valves 8 and the speed of blower 6 are continuously adjusted to form a closed-loop control until the maximum actual valve position feedback value MAX_OP is within the optimal opening range.
[0046] The SOFC multi-channel airflow control method in this embodiment features dual closed-loop control: a large closed-loop control of the blower 6 to regulate the total airflow, and an independent flow closed-loop control of each air channel to regulate the distribution ratio of the total airflow in each air channel. This is a control strategy that prioritizes independent flow allocation for each air channel while providing a fallback for total flow regulation of the blower 6. While meeting the airflow requirements of each air channel, it significantly reduces the frequency of blower 6 speed adjustments and improves system stability. Specifically, by collecting the actual flow of each air channel in real time and comparing it with the target flow, the opening of the corresponding electric regulating valve 8 is controlled and adjusted based on the comparison results. This makes the actual flow of each air channel approach the target flow, decoupling the flow of multiple air channels and achieving independent closed-loop control of the flow of multiple air channels. Based on independent flow control for each air path, when the flow rate of each air path fluctuates, it is not necessary to adjust the speed of blower 6. Instead, by comparing the maximum actual valve position feedback value with the optimal opening range of electric regulating valve 8, the speed of blower 6 is adjusted only when the maximum actual valve position feedback value exceeds the optimal opening range. When the maximum actual valve position feedback value is within the optimal opening range, the speed of blower 6 does not need to be adjusted, thus reducing the frequency of blower 6 speed adjustment and improving system stability.
[0047] In one implementation, a target valve position for the blower is set within the optimal opening range. This target valve position is near the midpoint of the optimal opening range, representing a precise target value close to the midpoint. For example, if the optimal opening range is 50%-85%, the target valve position is 70%. When the maximum actual valve position feedback value is greater than the upper limit of the optimal opening range or less than the lower limit, the speed of the blower 6 is adjusted to gradually restore the maximum actual valve position feedback value to the target valve position. The target valve position is near the midpoint of the optimal opening range, and there is a significant difference between the target valve position and both the upper and lower limits of the optimal opening range. This provides the electric regulating valve 8 with a large adjustment margin during subsequent operation, avoiding frequent adjustments to the blower 6 speed.
[0048] In one implementation, when the SOFC system load changes (e.g., when power generation is adjusted), the required gas quantity changes accordingly, the system's air-fuel ratio changes, and the air flow rate in the main air path changes accordingly, triggering the electric regulating valve 8 of the main air path. The change in gas quantity, in order to track the burner 5 temperature target value, causes the flow rate target value of the final-stage bypass to change accordingly, triggering the electric regulating valve 8 of the final-stage bypass. Correspondingly, the system's electrochemical reaction exothermics and stack temperature change, and the flow rates of the first-stage bypass and intermediate bypass also change accordingly to maintain the stack operating temperature, triggering the electric regulating valves 8 of the first-stage bypass and intermediate bypass. At this time, it is necessary to update the target flow rates of each air path calculated by the system control in real time. The system repeats steps S1~S5 to achieve dynamic adaptation of the flow rates of each air path. This ensures a stable SOFC cathode air supply while maintaining system temperature balance, guaranteeing efficient electrochemical reactions. The specific updates of the target flow rates of each air path involve stack inlet and outlet temperature control, current control, and reformer temperature control, which are not part of the inventive concept of this invention and will not be elaborated further.
[0049] In one implementation, the actual flow signals of each air path are acquired in real time and then soft-filtered to filter out signal noise under high-temperature conditions, thereby improving the detection accuracy of the actual flow.
[0050] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.
Claims
1. A method for controlling multiple airflow channels in an SOFC (Self-Containing Filter) system, characterized in that: Includes the following steps: S1. System initialization and parameter setting: Calculate and set the target flow rates for the main air path and multiple air bypasses; Set the optimal opening range of the electric regulating valve (8) in each air path; S2. Independent flow control of each air path: Real-time acquisition of the actual flow of each air path, comparison of the actual flow of each air path with the target flow, and control adjustment of the opening of the electric regulating valve (8) of the corresponding air path according to the comparison result, so that the actual flow of each air path approaches the target flow, so as to realize independent closed-loop control of the flow of multiple air paths. S3. Extract the maximum value of valve position of each air path: collect the actual valve position feedback value of the electric regulating valve (8) of each air path in real time, and compare and calculate the maximum value among all actual valve position feedback values. S4. Adjust the speed of blower (6) based on the maximum actual valve position feedback value: Compare the maximum actual valve position feedback value obtained in step S3 with the optimal opening range of the electric regulating valve (8) set in step S1, and control the speed of blower (6) according to the comparison result so that the maximum actual valve position feedback value is stable within the optimal opening range. S5. Repeat steps S2 to S4 to form a closed-loop control.
2. The SOFC multi-channel airflow control method according to claim 1, characterized in that: In step S4: If the maximum actual valve position feedback value is greater than the upper limit of the optimal opening range, the speed of the blower (6) is increased to increase the total air supply, so that the maximum actual valve position feedback value gradually decreases to the optimal opening range. If the maximum actual valve position feedback value is less than the lower limit of the optimal opening range, reduce the speed of the blower (6) to reduce the total air supply, so that the maximum actual valve position feedback value gradually rises to the optimal opening range. If the maximum actual valve position feedback value is within the optimal opening range, the blower (6) will maintain its current speed to avoid frequent speed adjustments that could cause system oscillations.
3. The SOFC multi-channel airflow control method according to claim 2, characterized in that: Set the target valve position of the blower within the optimal opening range. The target valve position of the blower is close to the middle value of the optimal opening range. When the maximum actual valve position feedback value is greater than the upper limit of the optimal opening range or less than the lower limit of the optimal opening range, adjust the speed of the blower (6) so that the maximum actual valve position feedback value gradually returns to the target valve position of the blower, thereby increasing the adjustment margin of the electric regulating valve (8) and reducing the adjustment frequency of the blower (6).
4. The SOFC multi-channel airflow control method according to claim 3, characterized in that: In step S1, the optimal opening range is 50%-85%, and the target valve position for the fan is 70%.
5. The SOFC multi-channel airflow control method according to any one of claims 1-4, characterized in that: In step S2, after comparing the actual flow rate of each air path with the target flow rate, feedforward compensation is first performed according to the characteristic curve of the electric regulating valve to quickly respond to the valve opening required for the target flow rate. Then, based on the comparison results, the opening of the electric regulating valve (8) of each air path is finely adjusted through the feedback control of the independent flow PID controller of each air path to achieve independent closed-loop control and fast response of the flow rate of multiple air paths. Preferably, in step S4, after comparing the maximum actual valve position feedback value with the optimal opening range, when the speed of the blower (6) needs to be adjusted, the system performs feedforward compensation based on the characteristic curve of the blower (6) to respond quickly to the vicinity of the required speed of the blower (6) in advance, and then finely adjusts the speed of the blower (6) through feedback control of the blower PID controller.
6. The SOFC multi-channel airflow control method according to claim 1, characterized in that: When the SOFC system load changes, the target flow rate of the corresponding air path is updated in real time. The system repeats steps S1 to S5 to achieve dynamic adaptation of the flow rate of each air path. Preferably, in step S1, the minimum operating speed and the maximum operating speed of the fan are set.
7. The SOFC multi-channel airflow control method according to claim 1, characterized in that: In step S2, the actual flow signals of each air path are soft-filtered in real time to filter signal noise under high temperature environment, so as to improve the detection accuracy of actual flow.
8. An air supply system for implementing the SOFC multi-channel airflow control method according to any one of claims 1-7, characterized in that: Includes a blower (6), which is connected to the cathode inlet of the fuel cell stack via an air main line. Multiple air bypasses are connected in parallel on the air main line. Flow sensors (7) and electric regulating valves (8) are installed on the air main line and each bypass. The electric regulating valves (8) are equipped with valve position feedback modules.
9. The air supply system according to claim 8, characterized in that: An air bypass includes at least a primary bypass and a final bypass. The outlet of the first-stage bypass is connected to the cathode inlet of the fuel cell stack, and the outlet of the last-stage bypass is connected to the cathode outlet of the fuel cell stack.
10. A power generation system, characterized in that: Includes the fuel cell stack and the air supply system as described in claim 9; A fuel cell stack includes one or more fuel cell stack groups; When multiple fuel cell stacks are set up, the cathode outlet of the upper-level fuel cell stack is connected to the cathode inlet of the lower-level fuel cell stack, and the air supply system also includes one or more intermediate bypasses. The intermediate bypass is used to supply air to the cathode exhaust gas supply pipeline of the adjacent fuel cell stack to adjust the cathode inlet temperature of the corresponding fuel cell stack cathode. The outlet of the first-stage bypass is connected to the cathode inlet of the first-stage fuel cell stack, and the outlet of the last-stage bypass is connected to the cathode outlet of the last-stage fuel cell stack.