Air control system and control method of fuel cell

Abstract

The present invention provides an air control system and a control method for a fuel cell, belonging to the technical field of fuel cells. The system includes: an air filter, an air compressor, and a controller; the air filter, the air compressor, and the air inlet of the fuel cell stack are connected in sequence, and an air flow meter is arranged at the outlet of the air filter; the controller is used to perform PI adjustment on the set value of the rotational speed of the air compressor when the actual flow rate collected by the air flow meter is stable and the error between the actual flow rate and the target flow rate is greater than the first preset error value, and when the set value of the rotational speed exceeds the rotational speed integral saturation range, correct the calibrated value of the rotational speed based on the error and a preset gain coefficient. The present invention adaptively adjusts the set value of the rotational speed of the air compressor based on the error between the actual air flow rate and the target flow rate and the gain coefficient, and solves the technical problem of the deviation between the actual air flow rate and the target flow rate caused by the plateau environment, the change of the characteristics of the air compressor, or the change of the flow resistance of the air pipeline.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and particularly relates to an air control system and a control method for a fuel cell. Background Art

[0002] In a fuel cell system, air can be delivered to the fuel cell system by an air compressor. When the fuel cell system is in a plateau environment, the performance of the air compressor decays, resulting in changes in static characteristics, or the air path of the fuel cell system changes with the tailpipe of different vehicle models, and the air flow resistance changes, the set value of the air compressor speed at the target power will change greatly. In the traditional method for adjusting the set value of the air compressor speed, the deviation between the actual air flow and the target flow cannot be eliminated, resulting in the fuel cell system being unable to output the required power. Summary of the Invention

[0003] In view of this, it is necessary to provide an air control system and a control method for a fuel cell to solve the technical problem that the deviation between the actual air flow and the target flow cannot be eliminated in the existing technical solutions.

[0004] To solve the above problems, the present invention provides an air control system for a fuel cell, including: an air filter, an air compressor, and a controller;

[0005] The air filter, the air compressor, and the intake port of the fuel cell stack are connected in sequence, and an air flow meter is provided at the outlet of the air filter;

[0006] The controller is configured to perform PI adjustment on the set value of the air compressor speed when the actual flow collected by the air flow meter is stable and the error between the actual flow and the target flow is greater than a first preset error value, and correct the set value of the air compressor speed based on the error and a preset gain coefficient when the set value exceeds the speed integral saturation range.

[0007] In a possible implementation manner, the controller is further configured to obtain the target loading current corresponding to the fuel cell stack before the actual flow collected by the air flow meter is stable, determine the calibrated value of the air compressor speed based on the target loading current, and control the air compressor to rotate based on the calibrated value of the air compressor speed.

[0008] In a possible implementation manner, the controller is further configured to control the air compressor to rotate at a first fixed speed value when the actual flow collected by the air flow meter is stable and the error between the actual flow and the target flow is less than or equal to the first preset error value.

[0009] In a possible implementation, the controller is further configured to, when the rotation speed set value does not exceed the threshold range corresponding to the rotation speed integral saturation interval, determine whether the actual flow rate and the actual rotation speed of the air compressor reach the surge state based on the air compressor flow rate - rotation speed surge line, and in the case of reaching the surge state, feedback an air compressor surge fault; the threshold range corresponding to the rotation speed integral saturation interval is obtained by expanding a first set range from the upper and lower limits of the rotation speed integral saturation interval.

[0010] In a possible implementation, the air control system of the fuel cell further includes: a humidifier; the air filter, the air compressor, the humidifier, and the inlet of the fuel cell stack are connected in sequence.

[0011] In a possible implementation, the air control system of the fuel cell further includes: a back - pressure valve and a pressure sensor, the back - pressure valve is arranged on the pipeline between the outlet of the fuel cell stack and the humidifier, and the pressure sensor is arranged on the pipeline of the inlet of the fuel cell stack;

[0012] The controller is further configured to, after the actual pressure collected by the pressure sensor is stable and the error between the actual pressure and the target pressure is greater than a second preset error value, perform PI adjustment on the angle set value of the back - pressure valve, and in the case where the angle set value of the back - pressure valve exceeds the threshold range corresponding to the angle integral saturation interval, correct the angle set value of the back - pressure valve; the threshold range corresponding to the angle integral saturation interval is obtained by expanding a second set range from the upper and lower limits of the angle integral saturation interval.

[0013] In a possible implementation, the controller is further configured to, when the angle set value of the back - pressure valve set by the controller does not exceed the threshold range corresponding to the angle integral saturation interval, set the back - pressure valve based on the fixed angle value of the back - pressure valve.

[0014] In a possible implementation, the controller is further configured to, before the actual pressure collected by the pressure sensor is stable, obtain the target load current corresponding to the fuel cell stack, determine the back - pressure valve angle calibration value based on the target load current, and control the setting of the back - pressure valve based on the back - pressure valve angle calibration value.

[0015] On the other hand, the present invention further provides an air control method for a fuel cell, the control method is applied to the control system described in any one of the above, and the method includes:

[0016] After the actual flow rate collected by the air flow meter is stable and the error between the actual flow rate and the target flow rate is greater than the first preset error value, the controller performs PI adjustment on the set value of the rotational speed of the air compressor, and when the set value of the rotational speed exceeds the rotational speed integral saturation range, the set value of the rotational speed is corrected based on the error and a preset gain coefficient.

[0017] In a possible implementation manner, the air control method for a fuel cell further includes:

[0018] After the actual pressure of the back pressure valve is stable and the error between the actual pressure and the target pressure is greater than the second preset error value, PI adjustment is performed on the set value of the angle of the back pressure valve, and when the set value of the angle of the back pressure valve exceeds the threshold range corresponding to the angle integral saturation range, the set value of the angle of the back pressure valve is corrected.

[0019] The beneficial effects of adopting the above implementation manner are as follows: The air control system and control method for a fuel cell provided by the present invention can first set an initial rotational speed for the air compressor through the controller to make the air compressor start working, and collect the flow rate at the outlet of the air filter through the air flow meter. After the actual flow rate collected by the air flow meter is stable, it can be judged whether there is an error between the actual flow rate and the target flow rate. If the error exceeds the expectation, it means that the error needs to be reduced. To reduce this error, the present invention adjusts the set value of the rotational speed of the air compressor by means of PI adjustment, and the rotational speed of the air compressor can be controlled through the set value of the rotational speed; during the PI adjustment process, if the set value of the rotational speed exceeds the rotational speed integral saturation range, it means that the error still exists, and then it is necessary to further correct the set value of the rotational speed based on the error and a preset gain coefficient, so as to adjust the actual flow rate, adjust the actual flow rate to be close to the target flow rate, ensure that the error is within a controllable range, and thus solve the technical problem that there is a deviation between the actual air flow rate and the target flow rate in the prior art solution due to changes in the plateau environment, characteristics of the air compressor, or flow resistance of the air pipeline. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0021] Figure 1 It is a schematic structural diagram of an embodiment of the air control system for a fuel cell provided by the present invention;

[0022] Figure 2Flow chart of an embodiment of the air control method for a fuel cell provided by the present invention;

[0023] Figure 3 Flow chart of another embodiment of the air control method for a fuel cell provided by the present invention;

[0024] Figure 4 Flow chart of yet another embodiment of the air control method for a fuel cell provided by the present invention. Detailed implementation manners

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present invention.

[0026] In the description of the embodiments of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0027] In the embodiments of the present invention, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, device, product or equipment including a series of steps or modules does not necessarily have to be limited to those clearly listed steps or modules, but may include other steps or modules not clearly listed or inherent to these processes, methods, products or equipment.

[0028] In the embodiments of the present invention, the naming or numbering of steps does not mean that the steps in the method flow must be executed in the time / logical order indicated by the naming or numbering. The named or numbered process steps can be changed in the execution order according to the technical purpose to be achieved, as long as the same or similar technical effects can be achieved.

[0029] Referring to "embodiments" herein means that the specific features, structures or characteristics described in conjunction with the embodiments can be included in at least one embodiment of the present invention. The phrase appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0030] The present invention provides an air control system and control method for a fuel cell, which will be described separately below.

[0031] As Figure 1As shown in the figure, the present invention provides an air control system for a fuel cell, which includes: an air filter 101, an air compressor 102, and a controller 104;

[0032] The air inlet of the air filter 101, the air compressor 102, and the fuel cell stack 103 are connected in sequence. An air flow meter 106 is provided at the outlet of the air filter 101, and a pressure sensor 105 is provided at the air inlet of the stack 103;

[0033] The controller 104 is used to perform PI regulation on the set value of the rotational speed of the air compressor 102 when the actual flow rate collected by the air flow meter 106 is stable and the error between the actual flow rate and the target flow rate is greater than the first preset error value. And when the set value of the rotational speed exceeds the rotational speed integral saturation range, the set value of the rotational speed is corrected based on the error and the preset gain coefficient.

[0034] It can be understood that a PI controller is a linear controller. It forms a control deviation based on the given value and the actual output value, and forms a control quantity through a linear combination of the proportion and integral of the deviation to control the controlled object.

[0035] In traditional anti-saturation adjustment methods, the adjustment amount of the PI regulator reaches integral saturation, and the deviation between the target flow rate and the actual flow rate cannot be further eliminated, resulting in the fuel cell system being unable to output the required power. In order to reduce a large amount of repetitive calibration work, the present invention will, without adding additional electrical components, during the steady-state operation of the fuel cell system, through an adaptive control method, adaptively correct the set value of the fuel cell air system, detect the surge of the air compressor 102, and calculate the maximum allowable pull load current of the air flow.

[0036] The controller 104 in the present invention is an FCU (fuel cell system control unit) controller. A PI controller is provided in this controller. The FCU controller collects the signals of the air flow meter 106, the pressure sensor 105, and the ambient temperature sensor, and outputs the set value of the rotational speed of the air compressor 102 and the set value of the back pressure valve angle after internal calculation of the FCU controller. The set value is also called the set value.

[0037] The initial set value of the rotational speed of the air compressor 102 is obtained by looking up a table according to the calculated and corrected target air flow rate. If there is an error between the actual flow rate and the target flow rate after the actual flow rate is stable, after PI regulation, the rotational speed of the air compressor 102 changes rapidly to respond to the target flow rate. However, in order to avoid the rotational speed of the air compressor 102 rising too high and causing surge, it is necessary to detect the surge line of the air compressor 102.

[0038] During the PI closed-loop regulation process, to avoid excessive PI regulation and slow convergence under transient variable load conditions, it is necessary to set upper and lower limit saturation processing for the integral link. When the integral link reaches the upper and lower limits of the saturation interval, it is determined that the PI closed-loop regulation is excessive and exceeds the saturation interval. If it is determined that the upper saturation limit is reached, the air flow pressure look-up table value (i.e., the speed calibration value) is increased according to a certain positive gain coefficient to obtain the corrected speed calibration value. This positive gain coefficient needs to be calibrated according to the characteristics of the fuel cell system. If it is determined that the lower saturation limit is reached, the air flow pressure look-up table value is decreased according to a certain negative gain coefficient. This negative gain coefficient also needs to be calibrated according to the characteristics of the fuel cell system. Through the two steps of determination and correction, the purpose of correcting the air flow pressure look-up table value of the air compressor 102 is achieved and stored in the controller eeprom register. After correction, the maximum air flow that can be provided at the maximum speed of the current air compressor 102 is obtained. According to the current of the fuel cell stack 103 and the characteristic curve of the air flow meter, the maximum allowable load current of the fuel cell system is determined. At this time, regardless of how the ambient temperature, altitude, and the characteristics of the air compressor 102 change, the look-up table value can be adaptively corrected, greatly improving the control robustness and adaptability of the air control system of the fuel cell, and at the same time avoiding the occurrence of surging of the air compressor 102 caused by excessive self-regulation.

[0039] The backpressure valve angle calibration value is obtained by looking up the table according to the calculated air inlet pressure to the stack. After the air pressure is stable, the actual and target pressure error values are judged. If the error is less than 2 - 3 kPa (this value can be determined according to the air pressure sensitivity test report of the fuel cell stack 103), the backpressure valve angle setting value is output. Otherwise, it enters the pressure-angle PI closed-loop control stage. If the PI closed-loop control does not exceed the saturation area, the surging is judged. Otherwise, the pressure-angle calibration value needs to be corrected, and the corrected look-up table value is stored in the eeprom register. After correction, the next cycle can quickly respond to the pressure demand of the fuel cell.

[0040] In some embodiments, the controller is further configured to obtain the target load current corresponding to the fuel cell stack 103 before the actual flow rate collected by the air flow meter 106 is stable, determine the speed calibration value of the air compressor 102 based on the target load current, and control the rotation of the air compressor 102 based on the speed calibration value of the air compressor 102.

[0041] It can be understood that when the system receives the startup instruction and the target power generation, the target power generation is converted into the system target load current, and the speed calibration value of the air compressor 102 is determined by looking up the table according to the target load current.

[0042] In some embodiments, the controller is further configured to control the rotation of the air compressor 102 at a first fixed rotational speed value after the actual flow rate collected by the air flow meter 106 is stable and the error between the actual flow rate and the target flow rate is less than or equal to a first preset error value.

[0043] It can be understood that the first preset error value can be 1 g / s. When the error between the actual flow rate and the target flow rate is less than or equal to the first preset error value, the rotational speed of the air compressor 102 remains unchanged.

[0044] In some embodiments, the controller is further configured to determine whether the actual flow rate and the actual rotational speed of the air compressor 102 reach a surge state based on the flow rate - rotational speed surge line of the air compressor 102 when the set rotational speed value does not exceed the threshold range corresponding to the rotational speed integral saturation range, and feedback a surge fault of the air compressor 102 when reaching the surge state; the threshold range corresponding to the rotational speed integral saturation range is obtained by expanding a first set range from the upper and lower limits of the rotational speed integral saturation range.

[0045] It can be understood that if the controller output value (i.e., the set rotational speed value of the air compressor 102 output by the controller) does not exceed ±1000 rpm of the integral saturation area, where ±1000 rpm is the first set range, determine whether the current actual flow rate and rotational speed reach the surge state according to the flow rate - rotational speed surge line of the air compressor 102. If on the surge line, feedback a surge fault of the air compressor 102, otherwise output a second fixed rotational speed value to control the rotation of the air compressor 102.

[0046] In some embodiments, the air control system of the fuel cell further includes: a humidifier 107; the air inlet of the air filter 101, the air compressor 102, the humidifier 107, and the fuel cell stack 103 are connected in sequence.

[0047] In some embodiments, the air control system of the fuel cell further includes: a back - pressure valve 108 and a pressure sensor 105. The back - pressure valve 108 is disposed on the pipeline between the outlet of the fuel cell stack 103 and the humidifier 107, and the pressure sensor 105 is disposed on the intake pipeline of the fuel cell stack 103;

[0048] The controller is further configured to perform PI adjustment on the angle set value of the back - pressure valve 108 after the actual pressure collected by the pressure sensor 105 is stable and the error between the actual pressure and the target pressure is greater than a second preset error value, and correct the angle set value of the back - pressure valve 108 when the angle set value of the back - pressure valve 108 exceeds the threshold range corresponding to the angle integral saturation range.

[0049] It can be understood that, it can be understood that, such asFigure 1 As shown in the figure, the air control system of the fuel cell includes an air filter 101, a mass flow meter, an air compressor 102, a humidifier 107, an air inlet stack pressure sensor 105, a back pressure valve 108, and a controller. The controller integrates an ambient temperature sensor, has a simple and compact structure, low cost, and is easy to be applied in engineering.

[0050] The second preset error value can be 2 - 3 kPa, for example, 2 kPa. The second preset error value can be determined according to the air pressure sensitivity test report of the stack 103. After the pressure is stabilized, if the error between the actual pressure and the target pressure does not exceed 2 kPa, the fixed angle of the first back pressure valve is output. If the error is greater than 2 kPa, the pressure-angle closed-loop PI control is entered.

[0051] In some embodiments, the controller is further configured to set the back pressure valve based on the fixed angle value of the back pressure valve when the set value of the angle of the back pressure valve by the controller does not exceed the threshold range corresponding to the angle integral saturation interval; the threshold range corresponding to the angle integral saturation interval is obtained by expanding the upper and lower limits of the angle integral saturation interval by a second set range.

[0052] It can be understood that if the output value of the pressure-angle PI closed-loop controller does not exceed ±5% of the integral saturation area, and ±5% is the second set range, the fixed angle of the second back pressure valve is output.

[0053] In some embodiments, the controller is further configured to obtain the target load current corresponding to the stack 103 before the actual pressure collected by the pressure sensor 105 is stabilized, determine the calibration value of the back pressure valve angle based on the target load current, and control the setting of the back pressure valve based on the calibration value of the back pressure valve angle.

[0054] It can be understood that when the system receives the startup instruction and the target power generation, the target power generation is converted into the system target load current, and the calibration value of the back pressure valve angle is determined by looking up the table according to the target load current pressure.

[0055] In summary, an air control system of a fuel cell provided by the present invention includes: an air filter 101, an air compressor 102, and a controller; the air inlet of the air filter 101, the air compressor 102, and the fuel cell stack 103 are connected in sequence, and an air flow meter 106 is arranged at the outlet of the air filter 101; the controller is configured to perform PI adjustment on the set value of the rotation speed of the air compressor 102 when the actual flow rate collected by the air flow meter 106 is stabilized and the error between the actual flow rate and the target flow rate is greater than the first preset error value, and correct the set value of the rotation speed based on the error and a preset gain coefficient when the set value of the rotation speed exceeds the rotation speed integral saturation interval.

[0056] The air control system of the fuel cell provided by the present invention can first set an initial speed for the air compressor 102 through the controller to make the air compressor 102 start working, and collect the flow rate at the outlet of the air filter 101 through the air flow meter 106. After the actual flow rate collected by the air flow meter 106 is stable, it can be judged whether there is an error between the actual flow rate and the target flow rate. If the error exceeds the expectation, it means that the error needs to be reduced. To reduce this error, the present invention adjusts the set value of the speed of the air compressor 102 in the way of PI regulation, and the speed of the air compressor 102 can be controlled through the set value of the speed; during the PI regulation process, if the set value of the speed exceeds the speed integral saturation range, it means that this error still exists, and it is necessary to further correct the set value of the speed based on the error and the preset gain coefficient, so as to realize the regulation of the actual flow rate, adjust the actual flow rate to be close to the target flow rate, ensure that the error is within the controllable range, and thus solve the technical problem that there is a deviation between the actual air flow rate and the target flow rate due to the plateau environment, the change of the characteristics of the air compressor or the change of the flow resistance of the air pipeline in the existing technical solution.

[0057] The present invention also provides an air control method for a fuel cell. The control method is applied to the control system described in any one of the above, as Figure 2 shown, the method includes:

[0058] S201. After the actual flow rate collected by the air flow meter 106 is stable and the error between the actual flow rate and the target flow rate is greater than the first preset error value, the controller performs PI regulation on the set value of the speed of the air compressor 102, and when the set value of the speed exceeds the speed integral saturation range, corrects the set value of the speed based on the error and the preset gain coefficient.

[0059] In some embodiments, the air control method for a fuel cell further includes:

[0060] After the actual pressure of the back pressure valve is stable and the error between the actual pressure and the target pressure is greater than the second preset error value, perform PI regulation on the set value of the angle of the back pressure valve, and when the set value of the angle of the back pressure valve exceeds the angle integral saturation range, correct the set value of the angle of the back pressure valve.

[0061] In another embodiment, as Figure 3As shown in the figure, when the system receives the power-on instruction and the target power generation power, it converts the target power generation power into the target load current of the system, determines the calibrated value of the rotational speed of the air compressor 102 by looking up the table according to the target load current. After the actual air flow rate after environmental temperature correction is stable, if the error between the actual flow rate and the target flow rate is less than 1 g / s, the set value 1 of the rotational speed of the air compressor 102 (i.e., the first fixed rotational speed value) is output. If the error is greater than 1 g / s, a PI closed-loop control (i.e., PI regulation) of the rotational speed of the air compressor 102 with respect to the air flow rate is performed.

[0062] If the output value of the PI controller does not exceed the integral saturation region of ±1000 rpm, according to the surge line of the air flow rate and rotational speed of the air compressor 102, it is judged whether the current actual flow rate and rotational speed reach the surge state. If it is on the surge line, the surge fault of the air compressor 102 is fed back. Otherwise, the set value 2 of the rotational speed of the air compressor 102 (i.e., the second fixed rotational speed value) is output.

[0063] When the output value of the PI controller exceeds the integral saturation region, after the rotational speed and air flow rate of the air compressor 102 are stable, the determination module enters the correction module to avoid frequent correction of the calibrated values of the flow rate and pressure during the dynamic load change process of the system. The correction module corrects the set value of the rotational speed of the air compressor 102 according to the error between the target and actual flow rates, and writes the corrected set value of the rotational speed into the controller eeprom register. According to the corrected calibrated value of the flow rate and rotational speed, the maximum air flow rate limit current is calculated. It should be noted that the corresponding relationship between the air flow rate and the rotational speed of the air compressor 102 is recorded in the flow rate-rotational speed table.

[0064] This embodiment can solve the following problems: The rotational speed of the air compressor 102 is greatly affected by the environmental temperature, the air tail discharge pipeline, and the altitude. By real-time correction of the look-up table values of the flow rate and rotational speed, the rotational speed of the air compressor 102 is adaptively controlled, avoiding repeated calibration work. During the adaptive closed-loop regulation process of the rotational speed of the air compressor 102, in order to avoid the surge problem of the air compressor 102, the surge state is detected in real time. At the same time, according to the corrected calibrated value of the flow rate and rotational speed, the maximum air flow rate that the air compressor 102 can provide is calculated to determine the maximum current allowed to be loaded under the current air control system state, avoiding the problem of lack of gas under the rated power of the fuel cell system.

[0065] This embodiment achieves the following effects: The rotational speed of the fuel cell air compressor 102 is adaptively controlled, greatly improving the system robustness and operation reliability, with simple control and high commercial value.

[0066] In another embodiment, as Figure 4As shown, when the system receives the power-on instruction and the target power generation, it converts the target power generation into the target load current of the system, and determines the initial calibration value of the back pressure valve angle by looking up the table according to the target load current pressure. After the pressure stabilizes, if the error between the actual pressure and the target pressure does not exceed 2 kPa, the set value 1 of the back pressure valve angle (i.e., the fixed angle value of the first back pressure valve) is output. If the error is greater than 2 kPa, it enters the pressure-angle closed-loop PI control.

[0067] If the output value of the pressure-angle PI closed-loop controller does not exceed ±5% of the integral saturation area, the set value 2 of the back pressure valve angle (i.e., the fixed angle value of the second back pressure valve) is output.

[0068] If the output value of the pressure-angle PI closed-loop controller exceeds ±5% of the integral saturation area, after the air pressure and the back pressure valve angle are stable, the determination module enters the pressure-angle correction module. The correction module corrects the set value of the back pressure valve angle according to the target and actual pressure errors, and writes the corrected angle set value into the controller eeprom register.

[0069] This embodiment solves the following problems: The angle of the back pressure valve is greatly affected by the ambient temperature, the air exhaust pipeline, and the altitude. By correcting the calibration value of the pressure angle in real time, the angle of the back pressure valve is adaptively controlled, avoiding repeated calibration work.

[0070] This embodiment achieves the following effects: The angle of the fuel cell back pressure valve is adaptively controlled, greatly improving the system robustness and operation reliability. The control is simple and has high commercial value.

[0071] The above has introduced in detail the air control system and control method of the fuel cell provided by the present invention. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A fuel cell air control system, characterized in that: include: An air filter, an air compressor, a humidifier, a back pressure valve, a pressure sensor and a controller; the air filter, the air compressor, the humidifier and the air inlet of the fuel cell stack are connected in sequence; the back pressure valve is arranged on the pipeline between the air outlet of the fuel cell stack and the humidifier, and the pressure sensor is arranged on the air inlet pipeline of the fuel cell stack; The outlet of the air filter is provided with an air flow meter; The controller is used to perform PI adjustment on the speed setting value of the air compressor when the actual flow rate collected by the air flow meter is stable and the error between the actual flow rate and the target flow rate is greater than a first preset error value, and to correct the speed setting value based on the error and a preset gain coefficient when the speed setting value exceeds the speed integral saturation interval; The controller is also used to perform PI adjustment on the angle setting value of the back pressure valve when the actual pressure collected by the pressure sensor is stable and the error between the actual pressure and the target pressure is greater than a second preset error value, and to correct the angle setting value of the back pressure valve when the angle setting value of the back pressure valve exceeds the threshold range corresponding to the angle integral saturation interval; the threshold range corresponding to the angle integral saturation interval is obtained after the upper and lower limits of the angle integral saturation interval are extended by the second setting range.

2. The air control system of the fuel cell according to claim 1, characterized in that: The controller is also used to obtain the target load current corresponding to the fuel cell stack before the actual flow collected by the air flow meter stabilizes, determine the air compressor speed calibration value based on the target load current, and control the rotation of the air compressor based on the air compressor speed calibration value.

3. The air control system of the fuel cell according to claim 1, characterized in that: The controller is also used to control the rotation of the air compressor according to a first fixed speed value after the actual flow collected by the air flow meter is stable and the error between the actual flow and the target flow is less than or equal to a first preset error value.

4. The air control system of the fuel cell according to claim 1, characterized in that: The controller is also used to determine whether the actual flow rate and the actual speed of the air compressor have reached a surge state based on the air compressor flow speed surge line when the speed setting value does not exceed the threshold range corresponding to the speed integral saturation interval, and to feedback an air compressor surge fault when the surge state is reached; the threshold range corresponding to the speed integral saturation interval is obtained after the upper and lower limits of the speed integral saturation interval are extended by a first set range.

5. The air control system of the fuel cell according to claim 4, characterized in that: The controller is further configured to set the back pressure valve based on a fixed angle value of the back pressure valve when the angle setting value of the back pressure valve set by the controller does not exceed a threshold range corresponding to an angle integral saturation interval.

6. The air control system of the fuel cell according to claim 4, characterized in that: The controller is also used to obtain the target load current corresponding to the battery stack before the actual pressure collected by the pressure sensor stabilizes, determine the back pressure valve angle calibration value based on the target load current, and control the setting of the back pressure valve based on the back pressure valve angle calibration value.

7. A fuel cell air control method, characterized in that: The control method is applied to the control system according to any one of claims 1 to 6, and the method comprises: After the actual flow rate collected by the air flow meter is stable, and the error between the actual flow rate and the target flow rate is greater than a first preset error value, the controller performs PI adjustment on the speed setting value of the air compressor, and when the speed setting value exceeds the speed integral saturation interval, the controller corrects the speed setting value based on the error and a preset gain coefficient; After the actual pressure of the back pressure valve is stabilized and the error between the actual pressure and the target pressure is greater than a second preset error value, the angle setting value of the back pressure valve is PI adjusted, and when the angle setting value of the back pressure valve exceeds the threshold range corresponding to the angle integral saturation interval, the angle setting value of the back pressure valve is corrected.

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