Hydrogen pressure control method, device and system in cold start process of fuel cell

Abstract

The invention relates to the technical field of fuel cells, and particularly discloses a hydrogen pressure control method, device and system in the cold start process of a fuel cell, and the control method comprises the steps: respectively calculating a first in-stack air pressure actual value and a second in-stack air pressure actual value according to in-stack air pressure measurement values, calculating an actual value of the in-reactor hydrogen pressure according to the measured value of the in-reactor hydrogen pressure, and calculating an in-reactor air pressure target value, a hydrogen-air pressure difference target value and a lower limit value of the in-reactor hydrogen pressure respectively according to the target current; calculating an in-reactor and out-reactor hydrogen pressure target value; and adjusting the air system control execution mechanism in real time to enable the first in-pile air pressure actual value to reach a target value, and adjusting the hydrogen system control execution mechanism in real time to enable the in-pile hydrogen pressure actual value to reach the target value. According to the invention, the pressure difference between the anode and the cathode of the fuel cell can be stabilized in a safe range, and an air system and a hydrogen system of the fuel cell can be ensured to have good dynamic responsiveness and stability at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a hydrogen pressure control method, a hydrogen pressure control device and a hydrogen pressure control system during a cold start process of a fuel cell. Background Art

[0002] Hydrogen fuel cells are power generation devices that convert chemical energy into electrical energy through electrochemical reactions. They have broad application prospects in the automotive and non-road fields. However, their R&D costs, cold start performance, and reliability are still difficult problems for commercialization. Reasonable fuel cell control strategies can not only improve steady-state stability and dynamic response performance, but also help improve the output efficiency and reliability of fuel cells.

[0003] There are two main methods for controlling the anode hydrogen pressure during the cold start process of a fuel cell in the prior art: one is to obtain the target hydrogen pressure based on the target air pressure and the target hydrogen-air pressure difference, and perform hydrogen pressure closed-loop control in combination with the actual hydrogen pressure entering the stack, and adjust the duty cycle of the hydrogen pressure control valve (hydrogen proportional valve or hydrogen injection valve) and the hydrogen exhaust valve in real time so that the actual hydrogen pressure entering the stack reaches the target value, thereby ensuring that the hydrogen-air pressure difference is within the allowable range; the other is to obtain the target hydrogen pressure based on the actual air pressure and the target hydrogen-air pressure difference, and perform hydrogen pressure closed-loop control, and adjust the duty cycle of the hydrogen pressure control valve and the hydrogen exhaust valve in real time so that the actual hydrogen pressure entering the stack reaches the target value, thereby ensuring that the hydrogen-air pressure difference is within the allowable range.

[0004] However, both of the above methods have certain defects: in method one, if the air system does not respond normally to the target air pressure, for example, the air pressure during cold start is generally open-loop controlled, resulting in a large difference between the actual air pressure and the target air pressure, and when the hydrogen system responds normally to the target hydrogen pressure, it will cause excessive pressure difference and cause damage to the fuel cell stack; in method two, since the actual air pressure changes in real time and fluctuates, when it is directly used to calculate the target hydrogen pressure and control it, it will inevitably cause the stability of the steady-state hydrogen pressure to deteriorate to a certain extent. If a larger air pressure filter is used, although the air pressure fluctuation amplitude can be reduced and the steady-state hydrogen pressure stability can be improved, the lag of the large filter will cause the air system's own pressure response to slow down and the dynamic performance of the fuel cell system to decrease.

[0005] Therefore, it is necessary to make improvements based on the above method and provide a hydrogen pressure control method for the cold start process of the fuel cell, which can not only meet the requirements of anode hydrogen stability and anode-cathode pressure difference, but also maintain good dynamic performance of the fuel cell system without affecting the dynamic responsiveness of the air system. At the same time, it can also prevent insufficient hydrogen pressure from causing the system to operate under hydrogen and cause damage to the fuel cell. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides a hydrogen pressure control method for a fuel cell cold start process, a hydrogen pressure control device for a fuel cell cold start process, and a hydrogen pressure control system for a fuel cell cold start process, so as to solve the problem in the prior art that when the fuel cell system couples the hydrogen pressure through air pressure to control the hydrogen pressure, the anode hydrogen pressure stability and the cathode air system dynamic response performance cannot be optimized at the same time, and at the same time, it can also prevent the problem of insufficient hydrogen pressure causing the system to operate under hydrogen and cause damage to the fuel cell.

[0007] As a first aspect of the present invention, a method for controlling the hydrogen pressure during a cold start of a fuel cell is provided. The method for controlling the hydrogen pressure during a cold start of a fuel cell comprises:

[0008] Step S1: obtaining a measured value of the air pressure entering the stack and a measured value of the hydrogen pressure entering the stack;

[0009] Step S2: calculating a first actual value of the air pressure entering the stack and a second actual value of the air pressure entering the stack according to the measured value of the air pressure entering the stack, and calculating an actual value of the hydrogen pressure entering the stack according to the measured value of the hydrogen pressure entering the stack, and calculating a target value of the air pressure entering the stack, a target value of the hydrogen-air pressure difference, and a lower limit value of the hydrogen pressure entering the stack according to the set target current;

[0010] Step S3: calculating a target value of the hydrogen pressure entering the stack according to the second actual value of the air pressure entering the stack, the target value of the hydrogen-air pressure difference and the lower limit value of the hydrogen pressure entering the stack;

[0011] Step S4: adjusting the air system control actuator in real time according to the target value of the air pressure entering the stack and the first actual value of the air pressure entering the stack, so that the first actual value of the air pressure entering the stack reaches the target value of the air pressure entering the stack; and at the same time, adjusting the hydrogen system control actuator in real time according to the target value of the hydrogen pressure entering the stack and the actual value of the hydrogen pressure entering the stack, so that the actual value of the hydrogen pressure entering the stack reaches the target value of the hydrogen pressure entering the stack.

[0012] Furthermore, the step S2 and step S3 further include:

[0013] performing a first filtering calculation and a second filtering calculation on the measured value of the air pressure entering the stack respectively to obtain a first actual value of the air pressure entering the stack and a second actual value of the air pressure entering the stack, and performing a third filtering calculation on the measured value of the hydrogen pressure entering the stack to obtain an actual value of the hydrogen pressure entering the stack, and checking a target air pressure curve, a target hydrogen-air pressure difference curve, and a target hydrogen pressure lower limit protection curve according to the target current respectively to obtain a target value of the air pressure entering the stack, a target value of the hydrogen-air pressure difference, and a lower limit value of the hydrogen pressure entering the stack;

[0014] A basic value of the hydrogen pressure entering the stack is obtained by summing the second actual value of the air pressure entering the stack and the target value of the hydrogen-air pressure difference, and then the larger one of the basic value of the hydrogen pressure entering the stack and the lower limit value of the hydrogen pressure entering the stack is taken as the target value of the hydrogen pressure entering the stack.

[0015] Further, the first filtering calculation is a sliding mean filtering algorithm used alone or a sliding mean filtering algorithm and a PT filtering algorithm used in combination; the second filtering calculation is a sliding mean filtering algorithm used alone or a sliding mean filtering algorithm and a PT filtering algorithm used in combination; the third filtering calculation is a sliding mean filtering algorithm used alone or a sliding mean filtering algorithm and a PT filtering algorithm used in combination; wherein, when the sliding mean filtering algorithm and the PT filtering algorithm are used in combination, it is necessary to first perform a sliding mean filtering calculation on the signal, and then perform a PT filtering calculation;

[0016] The formula of the sliding mean filtering algorithm is as follows:

[0017] Y j =(X j +X j+1 +…+X j+n-1 ) / n

[0018] Among them, X j is the jth sample input value, X j+1 is the j+1th sampling input value, n is the number of signal sampling times, Y j is the jth output value; the sampling time interval between two sampled input values ​​is the signal sampling period T;

[0019] The formula of the PT filtering algorithm is as follows:

[0020] Y j =f PT *Y j-1 +(1-f PT )*X j

[0021] Among them, X j is the input value for this time, Y j is the output value of this filtering, Y j-1 is the last filtering output value, f PT is the PT filter coefficient; the two input values ​​X j and X j-1 The sampling time interval is the signal sampling period T.

[0022] Furthermore, it also includes:

[0023] When the first filtering calculation is performed by using the sliding mean filtering algorithm alone, the signal sampling period in the sliding mean filtering algorithm is T 1S, the number of signal sampling times is n1; when the first filtering calculation is a combination of the sliding mean filtering algorithm and the PT filtering algorithm, the signal sampling period in the PT filtering algorithm is T 1P , the PT filter coefficient is f 1PT ;

[0024] When the second filtering calculation is performed by using the sliding mean filtering algorithm alone, the signal sampling period in the sliding mean filtering algorithm is T 2S , the number of signal sampling is n2; when the second filtering calculation is a combination of the sliding mean filtering algorithm and the PT filtering algorithm, the signal sampling period in the PT filtering algorithm is T 2P , the PT filter coefficient is f 2PT ;

[0025] When the third filtering calculation is performed by using the sliding mean filtering algorithm alone, the signal sampling period in the sliding mean filtering algorithm is T 3S , the number of signal sampling times is n3; when the third filtering calculation is a combination of the sliding mean filtering algorithm and the PT filtering algorithm, the signal sampling period in the PT filtering algorithm is T 3P , the PT filter coefficient is f 3PT ;

[0026] Among them, the signal sampling period T 2S Less than the signal sampling period T 1S , the signal sampling times n2 is greater than the signal sampling times n1.

[0027] Furthermore, the air system control actuator includes any one or more of an air compressor, a bypass valve and a back pressure valve, and the hydrogen system control actuator includes any one or more of a hydrogen proportional valve, a hydrogen injection valve, a hydrogen exhaust valve and a hydrogen circulation pump.

[0028] Furthermore, the adjusting the air system control actuator in real time according to the target value of the air pressure entering the stack and the first actual value of the air pressure entering the stack so that the first actual value of the air pressure entering the stack reaches the target value of the air pressure entering the stack, further includes:

[0029] The opening of the bypass valve and the opening of the back pressure valve are both set to fixed values, and the speed of the air compressor is adjusted in real time according to the target value of the air pressure entering the stack and the actual value of the first air pressure entering the stack;

[0030] When the first actual value of the stack-entering air pressure is lower than the target value of the stack-entering air pressure, the first actual value of the stack-entering air pressure is made to reach the target value of the stack-entering air pressure by increasing the rotation speed of the air compressor; when the first actual value of the stack-entering air pressure is higher than the target value of the stack-entering air pressure, the first actual value of the stack-entering air pressure is made to reach the target value of the stack-entering air pressure by reducing the rotation speed of the air compressor.

[0031] Furthermore, the real-time adjustment of the hydrogen system control actuator according to the target value of the hydrogen pressure entering the stack and the actual value of the hydrogen pressure entering the stack so that the actual value of the hydrogen pressure entering the stack reaches the target value of the hydrogen pressure entering the stack also includes:

[0032] Keeping the opening time of the hydrogen exhaust valve unchanged, the opening cycle of the hydrogen exhaust valve unchanged, and the speed of the hydrogen circulation pump unchanged, the opening of the hydrogen proportional valve or the opening time of the hydrogen injection valve is adjusted in real time according to the target value of the hydrogen pressure entering the stack and the actual value of the hydrogen pressure entering the stack;

[0033] When the actual value of the hydrogen pressure entering the stack is lower than the target value of the hydrogen pressure entering the stack, the actual value of the hydrogen pressure entering the stack reaches the target value of the hydrogen pressure entering the stack by increasing the opening of the hydrogen proportional valve or increasing the opening time of the hydrogen injection valve;

[0034] When the actual value of the hydrogen pressure entering the stack is higher than the target value of the hydrogen pressure entering the stack, the actual value of the hydrogen pressure entering the stack is made to reach the target value of the hydrogen pressure entering the stack by reducing the opening of the hydrogen proportional valve or reducing the opening time of the hydrogen injection valve.

[0035] As another aspect of the present invention, a hydrogen pressure control device for a fuel cell cold start process is provided, which is used to implement the hydrogen pressure control method for a fuel cell cold start process described above, and the hydrogen pressure control device for a fuel cell cold start process comprises:

[0036] An acquisition module is used to acquire a measured value of the air pressure entering the stack and a measured value of the hydrogen pressure entering the stack;

[0037] a calculation module, for calculating a first actual value of the stack-entry air pressure and a second actual value of the stack-entry air pressure according to the measured value of the stack-entry air pressure, and calculating an actual value of the stack-entry hydrogen pressure according to the measured value of the stack-entry hydrogen pressure, and calculating a target value of the stack-entry air pressure, a target value of the hydrogen-air pressure difference, and a lower limit value of the stack-entry hydrogen pressure according to a set target current; and calculating a target value of the stack-entry hydrogen pressure according to the second actual value of the stack-entry air pressure, the target value of the hydrogen-air pressure difference, and the lower limit value of the stack-entry hydrogen pressure;

[0038] The control module is used to adjust the air system control actuator in real time according to the target value of the air pressure entering the stack and the actual value of the first air pressure entering the stack, so that the actual value of the first air pressure entering the stack reaches the target value of the air pressure entering the stack, and at the same time, adjust the hydrogen system control actuator in real time according to the target value of the hydrogen pressure entering the stack and the actual value of the hydrogen pressure entering the stack, so that the actual value of the hydrogen pressure entering the stack reaches the target value of the hydrogen pressure entering the stack.

[0039] As another aspect of the present invention, a hydrogen pressure control system for a fuel cell cold start process is provided, comprising: a fuel cell stack, an air pressure sensor entering the stack, a hydrogen pressure sensor entering the stack, a controller, an air system control actuator, and a hydrogen system control actuator, wherein the controller comprises the hydrogen pressure control device for a fuel cell cold start process as described above;

[0040] Wherein, the stack-entering air pressure sensor, the stack-entering hydrogen pressure sensor, the air system control actuator and the hydrogen system control actuator are all electrically connected to the controller, the air system control actuator is used to adjust the air pressure entering the fuel cell stack, and the hydrogen system control actuator is used to adjust the hydrogen pressure entering the fuel cell stack;

[0041] The stack-entry air pressure sensor is installed on the pipeline at the air inlet of the fuel cell stack, and is used to measure the air pressure entering the fuel cell stack to output the stack-entry air pressure measurement value;

[0042] The hydrogen pressure sensor entering the stack is installed on the pipeline at the hydrogen inlet of the fuel cell stack, and is used to measure the pressure of hydrogen entering the fuel cell stack to output the measured value of the hydrogen pressure entering the stack.

[0043] Furthermore, the fuel cell stack is a solid polymer fuel cell composed of a plurality of stacked single cells, and the solid polymer fuel cell generates electricity by supplying hydrogen and air as reaction gases.

[0044] The hydrogen pressure control method for the cold start process of a fuel cell provided by the present invention has the following beneficial effects: two-way air pressure is obtained by using two-way filtering calculations on the stack air pressure sensor signal, one of which is used for air pressure control, and the other is used for hydrogen target pressure calculation and then hydrogen pressure control. Since the two-way filtering calculation parameters are independently set, it is more flexible. The system can adjust the actual control conditions of the fuel cell air system and the hydrogen system to obtain their respective optimal control parameters, thereby avoiding the influence of the air pressure control parameters itself while using the actual air pressure to couple the hydrogen pressure, so that the pressure control of the positive and negative electrodes of the fuel cell can achieve their respective optimal control effects. Therefore, the present invention can not only ensure that the pressure difference between the anode and cathode of the fuel cell is stable within a safe range, but also ensure that the fuel cell air system and the hydrogen system have good dynamic responsiveness and stability at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention, but do not constitute a limitation of the present invention.

[0046] Figure 1 The present invention is a flow chart of the hydrogen pressure control method for the cold start process of a fuel cell.

[0047] Figure 2 This is a flow chart of a specific implementation of the method for controlling hydrogen pressure during a cold start process of a fuel cell provided by the present invention.

[0048] Figure 3 A schematic diagram of the filtering calculation process of the measured value of the inlet air pressure provided by the present invention.

[0049] Figure 4 This is a structural diagram of the hydrogen pressure control system of the fuel cell cold start process provided by the present invention. DETAILED DESCRIPTION

[0050] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0051] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

[0052] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so as to describe the embodiments of the present invention described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0053] In this embodiment, a method for controlling the hydrogen pressure during a cold start of a fuel cell is provided. Figure 1 As shown, the hydrogen pressure control method of the fuel cell cold start process includes:

[0054] Step S1: obtaining a measured value of the air pressure entering the stack and a measured value of the hydrogen pressure entering the stack;

[0055] Step S2: calculating a first actual value of the air pressure entering the stack and a second actual value of the air pressure entering the stack according to the measured value of the air pressure entering the stack, and calculating an actual value of the hydrogen pressure entering the stack according to the measured value of the hydrogen pressure entering the stack, and calculating a target value of the air pressure entering the stack, a target value of the hydrogen-air pressure difference, and a lower limit value of the hydrogen pressure entering the stack according to the set target current;

[0056] Step S3: calculating a target value of the hydrogen pressure entering the stack according to the second actual value of the air pressure entering the stack, the target value of the hydrogen-air pressure difference and the lower limit value of the hydrogen pressure entering the stack;

[0057] Preferably, if Figure 2 As shown, the step S2 and step S3 further include:

[0058] The first filtering calculation 4201 and the second filtering calculation 4203 are respectively performed on the measured value 4101 of the air pressure entering the stack to obtain a first actual value 4202 and a second actual value 4204 of the air pressure entering the stack, and the third filtering calculation 4205 is performed on the measured value 4102 of the hydrogen pressure entering the stack to obtain an actual value 4206 of the hydrogen pressure entering the stack, and the target air pressure curve 4208, the target hydrogen-air pressure difference curve 4210 and the target hydrogen pressure lower limit protection curve 4212 are respectively checked according to the target current 4207 to obtain a target value 4209 of the air pressure entering the stack, a target hydrogen-air pressure difference value 4211 and a lower limit value 4213 of the hydrogen pressure entering the stack;

[0059] Among them, an example of the target hydrogen-air pressure difference curve 4210 is shown in Table 1 below. In the table, the X-axis is the target current, and the value corresponding to the Z-axis is the hydrogen-air pressure difference target value 4211 obtained by querying the two-dimensional curve by the target current. The hydrogen-air pressure difference target value is designed as a two-dimensional curve related to the target current, which has better flexibility and can ensure that the most suitable pressure difference range can be used under different currents.

[0060] Table 1 Target hydrogen-air pressure difference curve

[0061]

[0062] Among them, an example of the target hydrogen pressure lower limit protection curve 4212 is shown in Table 2 below. In the table, the X-axis is the target current, and the value corresponding to the Z-axis is the lower limit value 4213 of the hydrogen pressure entering the stack obtained by querying the two-dimensional curve through the target current. The lower limit value of the hydrogen pressure entering the stack in the curve needs to be determined based on the bench test, and is the hydrogen pressure corresponding to the minimum hydrogen supply required to ensure that each single battery can fully carry out the chemical reaction under each target current.

[0063] Table 2 Target hydrogen pressure lower limit protection curve

[0064]

[0065] A basic value 4214 of the hydrogen pressure entering the stack is obtained by summing the second actual value 4204 of the air pressure entering the stack and the target value 4211 of the hydrogen-air pressure difference. Then, the larger one of the basic value 4214 of the hydrogen pressure entering the stack and the lower limit 4213 of the hydrogen pressure entering the stack is taken as the target value 4215 of the hydrogen pressure entering the stack. This setting can prevent the fuel cell system from running under hydrogen and causing losses, thereby providing safety protection for the battery.

[0066] Specifically, the first filtering calculation 4201 is a sliding mean filtering algorithm used alone or a sliding mean filtering algorithm and a PT filtering algorithm used in combination; the second filtering calculation 4203 is a sliding mean filtering algorithm used alone or a sliding mean filtering algorithm and a PT filtering algorithm used in combination; the third filtering calculation 4205 is a sliding mean filtering algorithm used alone or a sliding mean filtering algorithm and a PT filtering algorithm used in combination; wherein, when the sliding mean filtering algorithm and the PT filtering algorithm are used in combination, it is necessary to first perform a sliding mean filtering calculation on the signal, and then perform a PT filtering calculation;

[0067] The formula of the sliding mean filtering algorithm is as follows:

[0068] Y j =(X j +X j+1 +…+X j+n-1 ) / n

[0069] Among them, X j is the jth sample input value, X j+1 is the j+1th sampling input value, n is the number of signal sampling times, Y j is the jth output value; the sampling time interval between two sampled input values ​​is the signal sampling period T;

[0070] The formula of the PT filtering algorithm is as follows:

[0071] Y j =f PT *Y j-1 +(1-f PT )*X j

[0072] Among them, X j is the input value for this time, Y j is the output value of this filtering, Y j-1 is the last filtering output value, f PT is the PT filter coefficient; the two input values ​​X j and X j-1 The sampling time interval is the signal sampling period T.

[0073] Specifically, the calculation parameters of the first filtering calculation, the second filtering calculation and the third filtering calculation are all independently set, as follows:

[0074] When the first filtering calculation is performed by using the sliding mean filtering algorithm alone, the signal sampling period in the sliding mean filtering algorithm is T 1S , the number of signal sampling times is n1; when the first filtering calculation is a combination of the sliding mean filtering algorithm and the PT filtering algorithm, the signal sampling period in the PT filtering algorithm is T 1P , the PT filter coefficient is f 1PT ;

[0075] When the second filtering calculation is performed by using the sliding mean filtering algorithm alone, the signal sampling period in the sliding mean filtering algorithm is T 2S , the number of signal sampling is n2; when the second filtering calculation is a combination of the sliding mean filtering algorithm and the PT filtering algorithm, the signal sampling period in the PT filtering algorithm is T 2P , the PT filter coefficient is f 2PT ;

[0076] When the third filtering calculation is performed by using the sliding mean filtering algorithm alone, the signal sampling period in the sliding mean filtering algorithm is T 3S, the number of signal sampling is n3; when the third filtering calculation is a combination of the sliding mean filtering algorithm and the PT filtering algorithm, the signal sampling period in the PT filtering algorithm is T 3P , the PT filter coefficient is f 3PT ;

[0077] Among them, the signal sampling period T 2S Less than the signal sampling period T 1S , the signal sampling number n2 is greater than the signal sampling number n1. This setting can enhance the stability of hydrogen pressure control while reducing hysteresis to maintain good dynamic responsiveness or sensitivity of hydrogen pressure control.

[0078] Since the calculation parameters of the first filtering calculation, the second filtering calculation and the third filtering calculation are all independently set and more flexible, the system can be adjusted separately according to the actual situation to obtain their respective optimal control parameters. This avoids the influence of the air pressure's own control parameters while using the actual air pressure to couple the hydrogen pressure, so that the pressure control of the positive and negative electrodes of the fuel cell can achieve their respective optimal control effects.

[0079] Specifically, the preferred values ​​of the calculation parameters of the first filtering calculation 4201, the second filtering calculation 4203, and the third filtering calculation 4205 are as follows:

[0080] In the first filtering calculation 4201, the signal sampling period T of the sliding mean filtering algorithm is 1S is 2ms, the signal sampling times n1 is 10, and the signal sampling period T of the PT filtering algorithm is 1P is 10ms, the filter coefficient f 1PT is 0.8;

[0081] In the second filtering calculation 4203, the signal sampling period T of the sliding mean filtering algorithm is 2S is 1ms, the signal sampling times n2 is 20, and the signal sampling period T of the PT filtering algorithm is 2P is 10ms, the filter coefficient f 2PT is 0.85;

[0082] In the third filtering calculation 4205, the signal sampling period T of the sliding mean filtering algorithm is 3S is 2ms, the signal sampling times n3 is 10, and the signal sampling period T of the PT filtering algorithm is 3P is 10ms, the filter coefficient f 3PT is 0.8.

[0083] Specifically, the calculation methods of the first filtering calculation 4201 and the third filtering calculation 4205 are similar to those of the second filtering calculation 4203. Taking the process of performing the second filtering calculation 4203 on the measured value 4101 of the air pressure entering the stack to obtain the second actual value 4204 of the air pressure entering the stack as an example, the filtering calculation process is described in detail. The process diagram is shown in FIG. Figure 3 As shown, the details are as follows:

[0084] Perform a second sliding mean filtering calculation according to the stack-entering air pressure measurement value 4101 (voltage signal) to obtain a second stack-entering air pressure sliding filtering value;

[0085] The initial value of the second air pressure is obtained by querying the characteristic curve of the air pressure sensor according to the second air pressure sliding filter value (the voltage filter value of the second air pressure sensor); wherein the characteristic curve of the air pressure sensor is the inherent characteristic curve of the sensor, as described in Table 3, in which the value corresponding to the X-axis is the second air pressure sliding filter value, and the value corresponding to the Z-axis is the initial value of the second air pressure obtained by querying the two-dimensional curve by the second air pressure sliding filter value;

[0086] Table 3 Characteristic curve of air pressure sensor for stack entry

[0087]

[0088] A PT filtering calculation is performed according to the initial value of the second air pressure entering the stack to obtain a PT filtered value of the second air pressure entering the stack, that is, an actual value 4204 of the second air pressure entering the stack.

[0089] Step S4: adjusting the air system control actuator in real time according to the target value of the air pressure entering the stack and the first actual value of the air pressure entering the stack, so that the first actual value of the air pressure entering the stack reaches the target value of the air pressure entering the stack, so as to realize air pressure control 4301; at the same time, adjusting the hydrogen system control actuator in real time according to the target value of the hydrogen pressure entering the stack and the actual value of the hydrogen pressure entering the stack, so that the actual value of the hydrogen pressure entering the stack reaches the target value of the hydrogen pressure entering the stack, so as to realize hydrogen pressure control 4302; thereby ensuring that the anode and cathode pressure difference of the fuel cell stack is maintained near the hydrogen-air pressure difference target value.

[0090] Preferably, the air system control actuator includes any one or more of an air compressor, a bypass valve and a back pressure valve, and the hydrogen system control actuator includes any one or more of a hydrogen proportional valve, a hydrogen injection valve, a hydrogen exhaust valve and a hydrogen circulation pump.

[0091] Preferably, during the cold start process of the fuel cell, the air system control actuator is adjusted in real time according to the target value of the stack air pressure and the first actual value of the stack air pressure so that the first actual value of the stack air pressure reaches the target value of the stack air pressure, and further includes:

[0092] The opening of the bypass valve and the opening of the back pressure valve are both set to fixed values ​​(i.e., remain unchanged during the cold start process), and the speed of the air compressor is adjusted in real time according to the target value of the air pressure entering the stack and the actual value of the first air pressure entering the stack;

[0093] When the first actual value of the stack-entering air pressure is lower than the target value of the stack-entering air pressure, the first actual value of the stack-entering air pressure is made to reach the target value of the stack-entering air pressure by increasing the rotation speed of the air compressor; when the first actual value of the stack-entering air pressure is higher than the target value of the stack-entering air pressure, the first actual value of the stack-entering air pressure is made to reach the target value of the stack-entering air pressure by reducing the rotation speed of the air compressor.

[0094] Preferably, for the cold start process of the fuel cell, the hydrogen system control actuator is adjusted in real time according to the target value of the hydrogen pressure entering the stack and the actual value of the hydrogen pressure entering the stack so that the actual value of the hydrogen pressure entering the stack reaches the target value of the hydrogen pressure entering the stack, and further includes:

[0095] Keeping the opening time of the hydrogen exhaust valve unchanged, the opening cycle of the hydrogen exhaust valve unchanged, and the speed of the hydrogen circulation pump unchanged, the opening degree (duty cycle) of the hydrogen proportional valve or the opening time of the hydrogen injection valve is adjusted in real time according to the target value of the hydrogen pressure entering the stack and the actual value of the hydrogen pressure entering the stack;

[0096] When the actual value of the hydrogen pressure entering the stack is lower than the target value of the hydrogen pressure entering the stack, the actual value of the hydrogen pressure entering the stack is made to reach the target value of the hydrogen pressure entering the stack by increasing the opening (duty cycle) of the hydrogen proportional valve or increasing the opening time of the hydrogen injection valve;

[0097] When the actual value of the hydrogen pressure entering the stack is higher than the target value of the hydrogen pressure entering the stack, the actual value of the hydrogen pressure entering the stack is made to reach the target value of the hydrogen pressure entering the stack by reducing the opening (duty cycle) of the hydrogen proportional valve or reducing the opening time of the hydrogen injection valve.

[0098] It should be understood that the present invention is different from and improved upon the hydrogen pressure control method for a cold start process of a fuel cell in the current industry in that:

[0099] At present, the industry uses actual air pressure to control the air system pressure, and at the same time calculates the target hydrogen pressure based on the actual air pressure and the target pressure difference between the positive and negative electrodes to control the hydrogen system pressure. Although the method of coupling the hydrogen pressure with the air pressure has been realized to stabilize the pressure difference between the positive and negative electrodes of the fuel cell within a safe range, the actual air pressure changes in real time and fluctuates. When it is directly used to calculate the target hydrogen pressure and control it, it will inevitably cause the stability of the steady-state hydrogen pressure to deteriorate to a certain extent. If a larger air pressure filter is used, although the air pressure fluctuation amplitude can be reduced and the steady-state hydrogen pressure stability can be improved, the lag of the large filter will cause the pressure response of the air system itself to slow down, thereby reducing the dynamic performance of the fuel cell system. Therefore, the current technical solutions in the industry cannot achieve the optimal air system pressure control performance and hydrogen system pressure control performance at the same time. The present invention uses two-way filtering to calculate the air pressure sensor signal entering the stack to obtain two-way air pressure, one of which is used for air pressure control, and the other is used for hydrogen target pressure calculation and then hydrogen pressure control. Since the two-way filtering calculation parameters are independently set, it is more flexible. The system can adjust the actual control conditions of the fuel cell air system and the hydrogen system to obtain their respective optimal control parameters, thus avoiding the influence of the air pressure control parameters while coupling the hydrogen pressure with the actual air pressure, so that the pressure control of the positive and negative electrodes of the fuel cell can achieve their respective optimal control effects. Therefore, the technical method provided by the present invention can not only ensure that the pressure difference between the anode and cathode of the fuel cell is stable within a safe range, but also ensure that the fuel cell air system and the hydrogen system have good dynamic responsiveness and stability at the same time.

[0100] The hydrogen pressure control method for the cold start process of a fuel cell provided by an embodiment of the present invention obtains two air pressures by using two-way filtering calculations on the stack air pressure sensor signal, one of which is used for air pressure control, and the other is used for hydrogen target pressure calculation and then hydrogen pressure control. Since the two-way filtering calculation parameters are independently set, it is more flexible. The system can adjust the actual control conditions of the fuel cell air system and the hydrogen system to obtain their respective optimal control parameters, thereby avoiding the influence of the air pressure control parameters itself while using the actual air pressure to couple the hydrogen pressure, so that the pressure control of the positive and negative electrodes of the fuel cell can achieve their respective optimal control effects. Therefore, the present invention can not only ensure that the pressure difference between the anode and cathode of the fuel cell is stable within a safe range, but also ensure that the fuel cell air system and the hydrogen system have good dynamic responsiveness and stability at the same time.

[0101] As another embodiment of the present invention, a hydrogen pressure control device for a fuel cell cold start process is provided, which is used to implement the hydrogen pressure control method for a fuel cell cold start process as described above, such as Figure 2 As shown, the hydrogen pressure control device of the fuel cell cold start process includes:

[0102] An acquisition module 41 is used to acquire a measured value of the air pressure entering the stack and a measured value of the hydrogen pressure entering the stack;

[0103] a calculation module 42, for calculating a first actual value of the stack-entry air pressure and a second actual value of the stack-entry air pressure according to the measured value of the stack-entry air pressure, and calculating an actual value of the stack-entry hydrogen pressure according to the measured value of the stack-entry hydrogen pressure, and calculating a target value of the stack-entry air pressure, a target value of the hydrogen-air pressure difference, and a lower limit value of the stack-entry hydrogen pressure according to a set target current; and calculating a target value of the stack-entry hydrogen pressure according to the second actual value of the stack-entry air pressure, the target value of the hydrogen-air pressure difference, and the lower limit value of the stack-entry hydrogen pressure;

[0104] The control module 43 is used to adjust the air system control actuator in real time according to the target value of the air pressure entering the stack and the actual value of the first air pressure entering the stack, so that the actual value of the first air pressure entering the stack reaches the target value of the air pressure entering the stack, and at the same time, adjust the hydrogen system control actuator in real time according to the target value of the hydrogen pressure entering the stack and the actual value of the hydrogen pressure entering the stack, so that the actual value of the hydrogen pressure entering the stack reaches the target value of the hydrogen pressure entering the stack.

[0105] The working principle of the hydrogen pressure control device for the cold start process of a fuel cell provided by the present invention can be referred to the description of the hydrogen pressure control method for the cold start process of a fuel cell in the foregoing text, and will not be repeated here.

[0106] As another embodiment of the present invention, a hydrogen pressure control system for a fuel cell cold start process is provided. Figure 4 As shown, it includes: a fuel cell stack 1, an air pressure sensor 2 for entering the stack, a hydrogen pressure sensor 3 for entering the stack, a controller 4, an air system control actuator 5 and a hydrogen system control actuator 6, wherein the controller 4 includes the hydrogen pressure control device for the cold start process of the fuel cell described above; wherein the controller 4 includes an acquisition module 41, a calculation module 42 and a control module 43; after the controller 4 is powered on and initialized, the acquisition module 41 starts to acquire the measured values ​​of the air pressure for entering the stack and the measured values ​​of the hydrogen pressure for entering the stack;

[0107] The air pressure sensor 2, the hydrogen pressure sensor 3, the air system control actuator 5 and the hydrogen system control actuator 6 are all electrically connected to the controller 4. The air system control actuator 5 is used to adjust the air pressure entering the fuel cell stack 1, and the hydrogen system control actuator 6 is used to adjust the hydrogen pressure entering the fuel cell stack 1.

[0108] The stack-entry air pressure sensor 2 is installed on the pipeline at the air inlet of the fuel cell stack 1, and is used to measure the air pressure entering the fuel cell stack 1 to output the stack-entry air pressure measurement value;

[0109] The hydrogen pressure sensor 3 entering the stack is installed on the pipeline at the hydrogen inlet of the fuel cell stack 1, and is used to measure the pressure of hydrogen entering the fuel cell stack 1 to output the measured value of the hydrogen pressure entering the stack.

[0110] It should be noted that the fuel cell stack 1 is a solid polymer fuel cell composed of a plurality of stacked single cells, and the solid polymer fuel cell generates electricity by supplying hydrogen (anode gas) and air (cathode gas) as reaction gases.

[0111] The working principle of the hydrogen pressure control system during the cold start process of the fuel cell provided in the embodiment of the present invention can be referred to the description of the hydrogen pressure control method during the cold start process of the fuel cell mentioned above, which will not be repeated here.

[0112] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for controlling hydrogen pressure during a cold start of a fuel cell, characterized in that: The hydrogen pressure control method of the fuel cell cold start process includes: Step S1: obtaining a measured value of the air pressure entering the stack and a measured value of the hydrogen pressure entering the stack; Step S2: calculating a first actual value of the air pressure entering the stack and a second actual value of the air pressure entering the stack according to the measured value of the air pressure entering the stack, and calculating an actual value of the hydrogen pressure entering the stack according to the measured value of the hydrogen pressure entering the stack, and calculating a target value of the air pressure entering the stack, a target value of the hydrogen-air pressure difference, and a lower limit value of the hydrogen pressure entering the stack according to the set target current; Step S3: calculating a target value of the hydrogen pressure entering the stack according to the second actual value of the air pressure entering the stack, the target value of the hydrogen-air pressure difference and the lower limit value of the hydrogen pressure entering the stack; Step S4: adjusting the air system control actuator in real time according to the target value of the air pressure entering the stack and the first actual value of the air pressure entering the stack, so that the first actual value of the air pressure entering the stack reaches the target value of the air pressure entering the stack; and at the same time, adjusting the hydrogen system control actuator in real time according to the target value of the hydrogen pressure entering the stack and the actual value of the hydrogen pressure entering the stack, so that the actual value of the hydrogen pressure entering the stack reaches the target value of the hydrogen pressure entering the stack.

2. The method for controlling hydrogen pressure during a cold start of a fuel cell according to claim 1, characterized in that: The steps S2 and S3 further include: performing a first filtering calculation and a second filtering calculation on the measured value of the air pressure entering the stack respectively to obtain a first actual value of the air pressure entering the stack and a second actual value of the air pressure entering the stack, and performing a third filtering calculation on the measured value of the hydrogen pressure entering the stack to obtain an actual value of the hydrogen pressure entering the stack, and checking a target air pressure curve, a target hydrogen-air pressure difference curve, and a target hydrogen pressure lower limit protection curve according to the target current respectively to obtain a target value of the air pressure entering the stack, a target value of the hydrogen-air pressure difference, and a lower limit value of the hydrogen pressure entering the stack; A basic value of the hydrogen pressure entering the stack is obtained by summing the second actual value of the air pressure entering the stack and the target value of the hydrogen-air pressure difference, and then the larger one of the basic value of the hydrogen pressure entering the stack and the lower limit value of the hydrogen pressure entering the stack is taken as the target value of the hydrogen pressure entering the stack.

3. The method for controlling hydrogen pressure during a cold start of a fuel cell according to claim 2, characterized in that: The first filtering calculation is a sliding mean filtering algorithm used alone or a sliding mean filtering algorithm and a PT filtering algorithm used in combination; the second filtering calculation is a sliding mean filtering algorithm used alone or a sliding mean filtering algorithm and a PT filtering algorithm used in combination; the third filtering calculation is a sliding mean filtering algorithm used alone or a sliding mean filtering algorithm and a PT filtering algorithm used in combination; wherein, when the sliding mean filtering algorithm and the PT filtering algorithm are used in combination, it is necessary to first perform a sliding mean filtering calculation on the signal and then perform a PT filtering calculation; The formula of the sliding mean filtering algorithm is as follows: Y j =(X j +X j+1 +…+X j+n-1 ) / n Among them, X j is the jth sample input value, X j+1 is the j+1th sampling input value, n is the number of signal sampling times, Y j is the jth output value; the sampling time interval between two sampled input values ​​is the signal sampling period T; The formula of the PT filtering algorithm is as follows: Y j =f PT *Y j-1 +(1-f PT )*X j Among them, X j is the input value for this time, Y j is the output value of this filtering, Y j-1 is the last filtering output value, f PT is the PT filter coefficient; the two input values ​​X j and X j-1 The sampling time interval is the signal sampling period T.

4. The method for controlling hydrogen pressure during a cold start of a fuel cell according to claim 3, characterized in that: Also includes: When the first filtering calculation is performed by using the sliding mean filtering algorithm alone, the signal sampling period in the sliding mean filtering algorithm is T 1S , the number of signal sampling times is n1; when the first filtering calculation is a combination of the sliding mean filtering algorithm and the PT filtering algorithm, the signal sampling period in the PT filtering algorithm is T 1P , the PT filter coefficient is f 1PT ; When the second filtering calculation is performed by using the sliding mean filtering algorithm alone, the signal sampling period in the sliding mean filtering algorithm is T 2S , the number of signal sampling times is n2; when the second filtering calculation is a combination of the sliding mean filtering algorithm and the PT filtering algorithm, the signal sampling period in the PT filtering algorithm is T 2P , the PT filter coefficient is f 2PT ; When the third filtering calculation is performed by using the sliding mean filtering algorithm alone, the signal sampling period in the sliding mean filtering algorithm is T 3S , the number of signal sampling is n3; when the third filtering calculation is a combination of the sliding mean filtering algorithm and the PT filtering algorithm, the signal sampling period in the PT filtering algorithm is T 3P , the PT filter coefficient is f 3PT ; Among them, the signal sampling period T 2S Less than the signal sampling period T 1S , the signal sampling times n2 is greater than the signal sampling times n1.

5. The method for controlling hydrogen pressure during a cold start of a fuel cell according to claim 1, characterized in that: The air system control actuator includes any one or more of an air compressor, a bypass valve and a back pressure valve, and the hydrogen system control actuator includes any one or more of a hydrogen proportional valve, a hydrogen injection valve, a hydrogen exhaust valve and a hydrogen circulation pump.

6. The method for controlling hydrogen pressure during a cold start of a fuel cell according to claim 5, characterized in that: The step of adjusting the air system control actuator in real time according to the target value of the air pressure entering the stack and the first actual value of the air pressure entering the stack so that the first actual value of the air pressure entering the stack reaches the target value of the air pressure entering the stack further includes: The opening of the bypass valve and the opening of the back pressure valve are both set to fixed values, and the speed of the air compressor is adjusted in real time according to the target value of the air pressure entering the stack and the actual value of the first air pressure entering the stack; When the first actual value of the stack-entering air pressure is lower than the target value of the stack-entering air pressure, the first actual value of the stack-entering air pressure is made to reach the target value of the stack-entering air pressure by increasing the rotation speed of the air compressor; when the first actual value of the stack-entering air pressure is higher than the target value of the stack-entering air pressure, the first actual value of the stack-entering air pressure is made to reach the target value of the stack-entering air pressure by reducing the rotation speed of the air compressor.

7. The method for controlling hydrogen pressure during a cold start of a fuel cell according to claim 5, characterized in that: The step of adjusting the hydrogen system control actuator in real time according to the target value of the hydrogen pressure entering the stack and the actual value of the hydrogen pressure entering the stack so that the actual value of the hydrogen pressure entering the stack reaches the target value of the hydrogen pressure entering the stack further includes: Keeping the opening time of the hydrogen exhaust valve unchanged, the opening cycle of the hydrogen exhaust valve unchanged, and the speed of the hydrogen circulation pump unchanged, the opening of the hydrogen proportional valve or the opening time of the hydrogen injection valve is adjusted in real time according to the target value of the hydrogen pressure entering the stack and the actual value of the hydrogen pressure entering the stack; When the actual value of the hydrogen pressure entering the stack is lower than the target value of the hydrogen pressure entering the stack, the actual value of the hydrogen pressure entering the stack reaches the target value of the hydrogen pressure entering the stack by increasing the opening of the hydrogen proportional valve or increasing the opening time of the hydrogen injection valve; When the actual value of the hydrogen pressure entering the stack is higher than the target value of the hydrogen pressure entering the stack, the actual value of the hydrogen pressure entering the stack is made to reach the target value of the hydrogen pressure entering the stack by reducing the opening of the hydrogen proportional valve or reducing the opening time of the hydrogen injection valve.

8. A hydrogen pressure control device for a fuel cell cold start process, used to implement the hydrogen pressure control method for a fuel cell cold start process as claimed in any one of claims 1 to 7, characterized in that: The hydrogen pressure control device for the cold start process of the fuel cell comprises: An acquisition module is used to acquire a measured value of the air pressure entering the stack and a measured value of the hydrogen pressure entering the stack; a calculation module, for calculating a first actual value of the stack-entry air pressure and a second actual value of the stack-entry air pressure according to the measured value of the stack-entry air pressure, and calculating an actual value of the stack-entry hydrogen pressure according to the measured value of the stack-entry hydrogen pressure, and calculating a target value of the stack-entry air pressure, a target value of the hydrogen-air pressure difference, and a lower limit value of the stack-entry hydrogen pressure according to a set target current; and calculating a target value of the stack-entry hydrogen pressure according to the second actual value of the stack-entry air pressure, the target value of the hydrogen-air pressure difference, and the lower limit value of the stack-entry hydrogen pressure; The control module is used to adjust the air system control actuator in real time according to the target value of the air pressure entering the stack and the actual value of the first air pressure entering the stack, so that the actual value of the first air pressure entering the stack reaches the target value of the air pressure entering the stack, and at the same time, adjust the hydrogen system control actuator in real time according to the target value of the hydrogen pressure entering the stack and the actual value of the hydrogen pressure entering the stack, so that the actual value of the hydrogen pressure entering the stack reaches the target value of the hydrogen pressure entering the stack.

9. A hydrogen pressure control system for a fuel cell cold start process, characterized in that: include: A fuel cell stack (1), an air pressure sensor (2) entering the stack, a hydrogen pressure sensor (3) entering the stack, a controller (4), an air system control actuator (5) and a hydrogen system control actuator (6), wherein the controller (4) comprises the hydrogen pressure control device for the cold start process of the fuel cell according to claim 8; The stack-entry air pressure sensor (2), the stack-entry hydrogen pressure sensor (3), the air system control actuator (5) and the hydrogen system control actuator (6) are all electrically connected to the controller (4); the air system control actuator (5) is used to adjust the air pressure entering the fuel cell stack (1), and the hydrogen system control actuator (6) is used to adjust the hydrogen pressure entering the fuel cell stack (1); The stack-entry air pressure sensor (2) is installed on a pipeline at the air inlet of the fuel cell stack (1) and is used to measure the air pressure entering the fuel cell stack (1) to output the stack-entry air pressure measurement value; The inlet hydrogen pressure sensor (3) is installed on the pipeline at the hydrogen inlet of the fuel cell stack (1) and is used to measure the pressure of hydrogen entering the fuel cell stack (1) to output the inlet hydrogen pressure measurement value.

10. The hydrogen pressure control system for a fuel cell cold start process according to claim 9, characterized in that: The fuel cell stack (1) is a solid polymer fuel cell composed of a plurality of stacked single cells, and the solid polymer fuel cell generates electricity by supplying hydrogen and air as reaction gases.

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