Fuel cell system idle speed control method, device, equipment and storage medium

Abstract

The present invention provides a fuel cell system idle speed control method, device, equipment and storage medium, the method comprising: obtaining a current request value of a fuel cell stack in the fuel cell system; taking the current request value as an adjustment target, dynamically adjusting the current of the fuel cell stack to make it tend to the current request value, determining the flow request value and pressure request value of air entering the stack based on the current adjusted current; adjusting the bypass throttle opening according to the current adjusted current, and feeding back the actual flow value and pressure actual value of air entering the stack; calculating according to the flow request value, the pressure request value, the flow actual value and the pressure actual value, obtaining the speed request value and back pressure throttle opening request value of the air compressor; controlling the air compressor speed and back pressure throttle opening according to the speed request value and the back pressure throttle opening request value, so as to complete the idle speed control of the fuel cell system. The present invention not only realizes the idle speed closed-loop control of the fuel cell system, but also improves the control accuracy and reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a fuel cell system idle speed control method, device, equipment and storage medium. Background Art

[0002] With the rapid development of new energy vehicles, fuel cell electric vehicles (FCEV) as one of the important research and development directions are vehicles that use hydrogen fuel as energy. Hydrogen and oxygen in the air generate electricity through electrochemical reactions in fuel cells to drive vehicles. They have the advantages of zero emissions, high conversion efficiency, and fast hydrogen refueling speed. As the power system of fuel vehicles, fuel cell systems are generally composed of fuel cell engines, power battery packs, electric drive systems, etc. Among them, the fuel cell engine that provides operating power for the fuel cell system is mainly composed of multiple subsystems such as fuel cell stacks, air supply subsystems, hydrogen supply subsystems, and water thermal management subsystems. The air supply subsystem and the hydrogen supply subsystem supply reaction gas to the cathode and anode of the fuel cell stack respectively, and the water thermal management subsystem controls the operating temperature of the fuel cell stack to be within the optimal range. The net output power of the fuel cell engine is the output power of the fuel cell stack minus the total parasitic power consumed by other subsystems, especially the parasitic power consumed by the air compressor in the air supply subsystem. Among them, the output power of the fuel cell stack is controlled by the output current. Therefore, by adjusting the current value output by the fuel cell stack, the net output power of the fuel cell engine can be controlled. However, when the fuel cell system is idling, that is, the fuel cell engine needs the support of various subsystems to operate under no-load conditions, that is, there are multiple factors affecting the idle control of the fuel cell system, especially the current of the fuel cell stack, the air flow and pressure entering the fuel cell stack, etc., which makes it difficult to achieve closed-loop control of the idle operation of the fuel cell system. There are problems with low control accuracy and reliability, which affects the service life of related components of the fuel cell system.

[0003] Patent CN111409509B discloses a fuel cell system and an idle speed control method thereof, which uses a PTC heater to consume the excess power generated by the fuel cell stack when the vehicle is idling, thereby improving the response speed of the idle speed control. However, the control accuracy of this solution is low. Chinese patent CN111430751B provides an idle speed oxygen supply control method and system for a fuel cell system, which uses an air compressor to consume the excess power generated by the fuel cell stack when the vehicle is idling, thereby achieving zero power output of the fuel cell stack to the entire vehicle. However, the reliability of this solution is low, and the real-time fluctuation of the air compressor power will cause fluctuations in the air pressure flow and pressure supplied to the stack, thereby damaging the stack.

[0004] Therefore, how to perform closed-loop control on the fuel cell system during idling and improve the accuracy and reliability of control is a problem that needs to be solved urgently. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, the present invention provides a fuel cell system idle speed control method, device, equipment and storage medium to solve at least one of the above-mentioned technical problems.

[0006] In a first aspect, the present invention provides a fuel cell system idle control method, comprising: when the fuel cell system of a target vehicle enters idle operation, obtaining a current request value of a fuel cell stack in the fuel cell system; taking the current request value as an adjustment target, dynamically adjusting the current of the fuel cell stack so that it tends to the current request value, and determining a flow request value and a pressure request value of air entering the stack based on the currently adjusted current; at the same time, adjusting the bypass throttle opening according to the currently adjusted current, and feeding back the actual flow value and the actual pressure value of the air entering the stack; calculating according to the flow request value, the pressure request value, the actual flow value and the actual pressure value to obtain a speed request value and a back-pressure throttle opening request value of an air compressor; controlling the air compressor speed and the back-pressure throttle opening according to the speed request value and the back-pressure throttle opening request value to complete the idle control of the fuel cell system.

[0007] In one embodiment of the present invention, the control of the air compressor speed and the back-pressure throttle opening according to the speed request value and the back-pressure throttle opening request value includes: determining a speed reference value of the air compressor and an opening reference value of the back-pressure throttle; performing difference operations on the flow request value and the actual flow value, and the pressure request value and the actual pressure value, respectively, to determine a flow control error and a pressure control error; performing decoupling operations on the flow control error and the pressure control error, respectively, to determine a speed compensation value of the air compressor and an opening compensation value of the back-pressure throttle; performing addition operations on the speed reference value and the speed compensation value of the air compressor, and the opening reference value and the opening compensation value of the back-pressure throttle, respectively, to obtain a speed request value and a back-pressure throttle opening request value; adjusting the speed of the air compressor to the speed request value, and adjusting the opening of the back-pressure throttle to the back-pressure throttle opening request value.

[0008] In one embodiment of the present invention, the adjustment of the bypass throttle opening includes: obtaining the average voltage of the fuel cell stack and the actual value of the bypass throttle opening, the average voltage is obtained by weighted averaging the voltages of each single cell in the fuel cell stack, and the average voltage will change according to the current change of the current adjusted; calculating the bypass throttle opening request value according to the difference between the average voltage and a preset voltage upper limit value, the bypass throttle opening request value is within a control range formed by a preset opening upper limit value and a preset opening lower limit value; adjusting the bypass throttle opening by the bypass throttle opening request value so that the average voltage is less than or equal to the preset voltage upper limit value.

[0009] In one embodiment of the present invention, before obtaining the current request value of the fuel cell stack in the fuel cell system, it also includes: obtaining the net power request value and the net power actual value of the engine in the fuel cell system; calculating the current request value of the fuel cell stack based on the net power request value and the net power actual value; wherein the difference between the net power actual value and the net power request value is calculated to determine the net power error; according to the net power actual value, a preset control parameter calibration table is queried to determine the proportional coefficient, integral coefficient and differential coefficient of the net power of the engine; the net power error is added to the calculated values ​​of the proportional coefficient, integral coefficient and differential coefficient of the net power of the engine to determine the current request value, and the current request value is within the control range formed by a preset current upper limit value and a preset current lower limit value.

[0010] In one embodiment of the present invention, after controlling the air compressor speed and the back-pressure throttle opening according to the speed request value and the back-pressure throttle opening request value, it also includes: obtaining the air compressor parasitic power, the air compressor parasitic power is determined by adjusting the air compressor speed and the back-pressure throttle opening; recalculating the net power actual value according to the air compressor parasitic power to obtain the updated current request value; and updating the current of the fuel cell stack in real time until the currently adjusted current is equal to the updated current request value.

[0011] In one embodiment of the present invention, before obtaining the net power request value and the net power actual value of the engine in the fuel cell system, the method further includes: obtaining the current actual value and the voltage actual value of the fuel cell stack, the conversion efficiency of the converter and the parasitic power of the water pump; the calculation formula of the net power actual value is:

[0012]

[0013] Among them, P act Indicates the actual value of the net power, I act Indicates the actual value of the current, Uact represents the actual value of the voltage, η dcdc represents the conversion efficiency, P cmpr represents the parasitic power of the air compressor, P wp represents the parasitic power of the water pump, and They respectively represent the filter functions corresponding to the parasitic power of the air compressor and the parasitic power of the water pump, and α1 and α2 respectively represent the filter parameters corresponding to the parasitic power of the air compressor and the parasitic power of the water pump.

[0014] In one embodiment of the present invention, before calculating the current request value of the fuel cell stack based on the net power request value and the net power actual value, it also includes: obtaining the power request value of the fuel cell system, the water temperature request value of the vehicle heating circuit, and the charging power limit value of the power battery; adjusting the water temperature of the vehicle heating circuit based on the water temperature request value, and the water temperature is adjusted within a control range formed by a preset water temperature upper limit value and a preset water temperature lower limit value to generate heater parasitic power; determining the idle boundary power of the fuel engine based on the heater parasitic power and the charging power limit value; determining the net power request value based on a first comparison result of the power request value and the charging power limit value, and a second comparison result of the idle boundary power and the preset idle boundary setting value, so that the determined net power request value is less than or equal to the charging power limit value.

[0015] In one embodiment of the present invention, the net power request value is determined based on a first comparison result between the power request value and the charging power limit value, and a second comparison result between the idle boundary power and the preset idle boundary setting value, including: if the power request value is less than or equal to the charging power limit value, the power request value is used as the power arbitration value of the engine; if the power request value is greater than the charging power limit value, the charging power limit value is used as the power arbitration value; if the idle boundary power is greater than or equal to the preset idle boundary setting value, any of the above power arbitration values ​​is used as the net power request value; if the idle boundary power is less than the preset idle boundary setting value, the idle boundary power is used as the net power request value.

[0016] In one embodiment of the present invention, the water temperature of the whole vehicle heating circuit is adjusted based on the water temperature request value, including: querying a preset first one-dimensional table according to the charging power limit value to determine the water temperature compensation value of the whole vehicle heating circuit; adding the water temperature compensation value and the water temperature request value to obtain a water temperature control request value; and adjusting the water temperature of the whole vehicle heating circuit to the water temperature control request value.

[0017] In one embodiment of the present invention, after the fuel cell system of the target vehicle enters idle operation, it also includes: if a shutdown signal is received from the target vehicle, the idle control of the fuel cell system is turned off, and the operating parameters of the idle control of the fuel cell system when the target vehicle is shut down are saved, and the operating parameters include the current of the fuel cell stack, the bypass throttle opening, the air compressor speed and the back pressure throttle opening.

[0018] In a second aspect, the present invention also provides a fuel cell system idle control device, comprising: an acquisition module, used to acquire a current request value of a fuel cell stack in the fuel cell system when the fuel cell system of a target vehicle enters idle operation; a dynamic adjustment module, used to dynamically adjust the current of the fuel cell stack to make it tend to the current request value with the current request value as an adjustment target, and determine the flow request value and pressure request value of air entering the stack based on the currently adjusted current; at the same time, the bypass throttle opening is adjusted according to the currently adjusted current, and the actual flow value and pressure actual value of the air entering the stack are fed back; a calculation module, used to calculate according to the flow request value, the pressure request value, the actual flow value and the actual pressure value to obtain the speed request value and back-pressure throttle opening request value of the air compressor; a control module, used to control the air compressor speed and the back-pressure throttle opening according to the speed request value and the back-pressure throttle opening request value to complete the idle control of the fuel cell system.

[0019] In a third aspect, the present invention also provides an electronic device comprising: one or more processors; a storage device for storing one or more programs, which, when executed by the one or more processors, enables the one or more processors to implement the fuel cell system idle control method as described in the above embodiments.

[0020] In a fourth aspect, the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor of a computer, enables the computer to execute the fuel cell system idle speed control method as described in the above embodiments.

[0021] Beneficial effects of the present invention: The present invention proposes a fuel cell system idle speed control method, device, equipment and storage medium. (1) When the fuel cell system enters idle operation, the current of the fuel cell is always tended to the current request regulation, realizing the closed-loop control of the fuel cell current, avoiding the current output of the fuel cell stack being too low, so that the heat generation power of the fuel cell system is always not lower than the heat dissipation power, and the temperature of the fuel cell stack can be kept stable. When the fuel cell engine exits idle operation, it has hydrothermal conditions for efficient electrochemical reactions, which is conducive to the rapid output of the corresponding power and improves the reliability of idle speed control; (2) The bypass throttle opening is adjusted, and the actual flow value and the actual pressure value of the air entering the stack are fed back, taking into account the idle speed control process. During the process, the change of the bypass throttle opening affects the air entering the fuel cell stack, that is, the actual flow rate and pressure of the air entering the stack, thereby improving the accuracy and reliability of the idle speed control; (3) the air compressor speed and back-pressure throttle opening are precisely controlled according to the air compressor speed request value and the back-pressure throttle opening request value. On the one hand, it avoids the air compressor speed being too low, which may reduce its service life. On the other hand, it takes into account the influence of the air flow rate and pressure entering the fuel cell stack on the idle operation. While avoiding the damage to the fuel cell stack caused by the fluctuation of the air pressure entering the fuel cell stack, it improves the accuracy and reliability of the idle speed control of the fuel cell system.

[0022] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present invention, and together with the specification, are used to explain the principles of the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0024] Figure 1 is a schematic diagram of a fuel cell system idle speed control related principle structure shown in an exemplary embodiment of the present invention;

[0025] Figure 2 is a flow chart of a fuel cell system idle speed control method according to an exemplary embodiment of the present invention;

[0026] Figure 3 is a schematic diagram showing a decoupling control principle of an air supply subsystem according to an exemplary embodiment of the present invention;

[0027] Figure 4 is a schematic diagram of an overall framework of idle speed control of a fuel cell system according to an exemplary embodiment of the present invention;

[0028] Figure 5 is a schematic diagram of the overall logic of idle speed control of a fuel cell system according to an exemplary embodiment of the present invention;

[0029] FIG6( a) is a schematic diagram showing a net power regulation effect according to an exemplary embodiment of the present invention;

[0030] FIG6( b ) is a schematic diagram showing an average voltage regulation effect according to an exemplary embodiment of the present invention;

[0031] FIG6( c ) is a schematic diagram showing the bypass throttle opening adjustment effect according to an exemplary embodiment of the present invention;

[0032] FIG6( d ) is a schematic diagram showing the flow rate regulation effect of air entering the stack according to an exemplary embodiment of the present invention;

[0033] FIG6( e) is a schematic diagram showing the pressure regulation effect of air entering the stack according to an exemplary embodiment of the present invention;

[0034] FIG6( f) is a schematic diagram showing the effect of adjusting the back pressure throttle opening according to an exemplary embodiment of the present invention;

[0035] FIG6( g) is a schematic diagram showing the effect of adjusting the speed of an air carrier according to an exemplary embodiment of the present invention;

[0036] Figure 7 is a block diagram of an idle speed control device for a fuel cell system shown in an exemplary embodiment of the present invention;

[0037] Figure 8 It is a schematic diagram of the structure of a computer system suitable for implementing the electronic device of the present invention, shown in an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0038] The following will describe the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention, not for limiting the scope of protection of the present invention.

[0039] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0040] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present invention difficult to understand.

[0041] See also Figure 1 , which is a schematic diagram of the principle structure related to the idle speed control of a fuel cell system according to an exemplary embodiment of the present invention.

[0042] like Figure 1 As shown, the structure related to the fuel cell system mainly consists of the fuel cell engine part and the whole vehicle part related to the power of the target vehicle. Among them, the fuel cell engine part includes the air supply subsystem, the fuel cell stack subsystem, the thermal management subsystem and the hydrogen supply subsystem. The air supply subsystem includes 1-air filter, which is used to filter out impurities and dust in the air and supply pure air to the cathode of the fuel cell; 2-intake mass flow sensor, which is used to measure the flow rate of air output from 1-air filter; 3-air compressor, which is used to compress air and provide air with appropriate pressure for 18-fuel cell stack, so that the pressure on the cathode side of 18-fuel cell stack is always in a more efficient range; 4-intercooler, which is used to Properly cool the compressed air to keep the cathode side of the 18-fuel cell stack in a suitable temperature range at all times; 5-humidifier, used to humidify the air to improve the efficiency of the electrochemical reaction of the 18-fuel cell stack; 6-air pressure sensor, used to measure the air pressure; 7-back pressure throttle, used to control the size of the gas exhaust channel of the cathode after the electrochemical reaction of the 18-fuel cell stack through its own opening; 8-bypass throttle, used to adjust and control the flow of air into the stack; 9-bypass mass flow sensor, used to measure the flow of compressed air.

[0043] Continue to refer to Figure 1The hydrogen supply subsystem includes 10-ejector, which is used to control the pressure and flow of hydrogen entering 18-fuel cell stack; 11-proportional valve, which is used to adjust the pressure of hydrogen entering the stack; 12-pressure reducing valve, which is used to adjust the pressure of hydrogen released by 13-hydrogen storage tank; 13-hydrogen storage tank, which is used to store hydrogen; 14-hydrogen-water separator, which is used to separate the gas and water of the humid gas after the anode reaction of 18-fuel cell stack; 15-purge valve, which is used to open intermittently to discharge the liquid water and nitrogen in the anode loop of 18-fuel cell stack into the atmosphere. The fuel cell stack subsystem includes 16-cell voltage collection harness, used to connect 18-fuel cell stack and cell voltage monitor (CVM); 17-CVM cell voltage monitor, used to accurately detect the voltage value of each cell in 18-fuel cell stack in real time; 18-fuel cell stack, composed of several cells pressed in series, used to convert chemical energy into electrical energy through electrochemical reactions of air and hydrogen occurring at the anode and cathode; 20-fuel cell-specific DCDC (i.e., converter of different DC current values), used to convert the voltage value of the output current of the fuel cell stack. 19-thermal management subsystem, used to control the operating temperature of 18-fuel cell stack within a suitable temperature range. The whole vehicle part includes 21-DCAC (i.e., direct current to alternating current converter), which is used to convert the direct current output by 18-fuel cell stack into alternating current; 22-drive motor, which is used to drive the target vehicle; 23-power battery, which is used to provide a power source for the target vehicle; 24-whole vehicle heating circuit PTC (i.e., heater), which is used to control 18-fuel cell stack to operate at a suitable temperature to provide air conditioning cooling and heating for the target vehicle; 25-one-way DCDC, which is used to transmit current to the whole vehicle heating circuit PTC24.

[0044] Continue to refer to Figure 1, 18-the cathode inlet of the fuel cell stack is connected to 6-the air pressure sensor, the cathode outlet is connected to 5-a part of the humidifier, the anode inlet is connected to 10-the ejector, and the anode outlet is connected to 14-the hydrogen-water separator. During the operation of the fuel cell system, the fresh air in the atmospheric environment passes through 1-the air filter, 2-the intake air mass flow sensor, 3-the air compressor, 4-the intercooler, 5-the humidifier, and 6-the air pressure sensor in sequence to enter the cathode of the fuel cell stack 18, and the cathode gas after the reaction passes through 5-the humidifier and 7-the back pressure throttle to be discharged to the atmosphere, wherein the pipeline at the outlet of the 3-air compressor is a three-way structure, wherein one way is connected to the 4-intercooler, one way is connected to the 2-intake air mass flow sensor, and the remaining way is connected to the 8-bypass throttle. By controlling the opening of the 8-bypass throttle, the high-pressure air at the outlet of the 3-air compressor can be led out to the atmospheric environment through the 8-bypass throttle and the 9-bypass mass flow sensor without entering the cathode 18 of the fuel cell stack. The hydrogen entering the anode inlet of the 18-fuel cell stack comes from the hydrogen provided by the 13-hydrogen storage tank and entering the 10-ejector through the 12-pressure reducing valve and the 11-proportional valve, and from the hydrogen provided by the 10-ejector after passing through the 14-hydrogen-water separator. The liquid water and nitrogen in the anode loop of the 15-purge valve are discharged to the atmosphere. The voltage of each fuel cell monomer in the 18-fuel cell stack is collected by the 17-CVM monomer voltage patroller, and each fuel cell monomer in the 18-fuel cell stack is connected to the 17-CVM monomer voltage patroller through the 16-monomer voltage collection harness. The 18-fuel cell stack is cooled by the 19-thermal management subsystem during operation. The positive and negative terminals of the 18-fuel cell stack are connected to the input port of the fuel cell dedicated DCDC20, the output voltage of the 18-fuel cell stack is boosted by the fuel cell dedicated DCDC20, and the 20-fuel cell dedicated DCDC output port is connected to the DC bus. The 23-power battery is connected to the DC bus, and the connection relationship with the fuel cell engine part is in parallel. 24- The vehicle heating circuit PTC obtains electric power from the DC bus through 25- One-way DCDC. 21- DCAC converts the DC power transmitted by the DC bus into AC power and then provides power to 22- the drive motor, thereby driving the target vehicle.

[0045] See also Figure 2 , is a flow chart of a fuel cell system idle speed control method shown in an exemplary embodiment of the present invention. As shown in 2, the fuel cell system idle speed control method at least includes steps S210 to S240, which are described in detail as follows:

[0046] Step S210 , when the fuel cell system of the target vehicle enters idle operation, a current request value of the fuel cell stack in the fuel cell system is obtained.

[0047] In one embodiment of the present invention, it is necessary to determine whether the fuel cell system enters idle operation, that is, the scenario in which the fuel cell engine needs to run at idle speed. For example, when the SOC (i.e., the charge state of the battery) of the power battery is too high, and the operating power of the fuel cell system required by the target vehicle is low, the fuel cell engine needs to reduce the output of the net power after starting to maintain idle operation, so as to avoid the actual value of the net power of the fuel cell engine exceeding the chargeable power (charging power limit value) of the power battery, resulting in overcharging of the power battery; when the target vehicle is stationary in a low temperature environment and the chargeable power of the power battery is low, the fuel cell engine needs to maintain idle operation to avoid high-power charging of the power battery in a low temperature environment, which will cause the attenuation of the power battery performance and cause safety problems.

[0048] Specifically, the current request value is determined by:

[0049] Obtain a net power request value and an actual net power value of an engine in a fuel cell system; calculate a current request value of a fuel cell stack according to the net power request value and the actual net power value; wherein, calculate the difference between the actual net power value and the net power request value to determine a net power error; query a preset control parameter calibration table according to the actual net power value to determine a proportional coefficient, an integral coefficient and a differential coefficient of the net power of the engine; perform addition operations on the net power error and the calculated values ​​of the proportional coefficient, the integral coefficient and the differential coefficient of the net power of the engine, respectively, to determine a current request value, wherein the current request value is within a control range formed by a preset current upper limit value and a preset current lower limit value.

[0050] In one embodiment of the present invention, the net power request value of the engine represents the net power expected to be output by the fuel cell engine, the actual net power value of the engine represents the net power actually output by the fuel cell engine, and the current request value of the fuel cell stack represents the current value expected to be output by the fuel cell stack.

[0051] The calculation formula of the current request value is as follows:

[0052]

[0053] Wherein, in formula (1), I req Indicates the current request value, P act Indicates the actual value of net power, P req represents the net power request value, k p represents the proportionality factor with respect to net power, k i represents the integral coefficient about net power, k d represents the differential coefficient with respect to net power, I upper Indicates the preset current upper limit, I lower Indicates the preset current lower limit value.

[0054] About k p , k i and k d The calculation formulas are:

[0055] k p =f p (P req ,ΔP) Formula (2)

[0056]

[0057] k d =f d (P req ,ΔP) Formula (4)

[0058] Among them, P in formula (2) to formula (4) req Indicates the net power request value, ΔPf p Indicates the power load amplitude, f i and f d The proportionality coefficient k p , integration coefficient k i and the differential coefficient k p A binary function of the net power request value and the power load amplitude; I upper Indicates the preset current upper limit, I lower Indicates the preset current lower limit value.

[0059] In one embodiment of the present invention, the power request value P req The binary function f of the power load amplitude ΔP p (P req ,ΔP),f i (P req ,ΔP) and f d (P req ,ΔP can be obtained by continuous calibration tests, as follows:

[0060] Firstly, the loading amplitude is an integer multiple of 5% (i.e. 5% PE) of the rated power of the fuel cell engine, and the loading amplitudes tested at this time are the net power loading effects of 5% PE, 10% PE, 15% PE, 20% PE ... 100% PE respectively; the loading amplitude is an integer multiple of 5% (i.e. 5% PE) of the rated power of the fuel cell engine, that is, the net power loading effects of the tested loading amplitudes are 5% PE, 10% PE, 15% PE, 20% PE ... 100% PE respectively, and the PID (proportion integration differentiation) parameters under different loading amplitudes, i.e. the proportional coefficient, the integral coefficient, and the differential coefficient are obtained by calibration.

[0061] Then, the load reduction amplitude is taken as an integer multiple of 5% of the rated power of the fuel cell engine, that is, the load reduction amplitudes tested are 5% PE, 10% PE, 15% PE, 20% PE...100% PE net power load reduction effects, and the PID parameters under different load reduction amplitudes are calibrated.

[0062] Finally, taking 5% of the rated power of the fuel cell engine as the test step, the power stability effect of each steady-state power point in the range of 0% PE-100% PE was tested respectively, and the PID parameters at different steady-state power points were calibrated; the PID parameters calibrated at different loading amplitudes, different load reduction amplitudes and different steady-state power points were summarized and sorted to form a two-dimensional calibration table as f p (P req ,ΔP),f i (P req ,ΔP) and f d (P req ,ΔP).

[0063] Through the above-mentioned method, the current of the fuel cell stack is maintained within the control range formed by the preset current upper limit value and the preset current lower limit value, so that the thermal power generated by the fuel cell system is always not lower than the heat dissipation power, and the temperature of the fuel cell stack can be kept stable. This enables the fuel cell engine to have hydrothermal conditions for efficient electrochemical reactions at the initial stage of exiting the idle state, which is conducive to the rapid power output of the fuel cell engine.

[0064] The actual value of the net power of the fuel cell engine is determined in the following manner:

[0065] Obtaining the actual current value and voltage value of the fuel cell stack, the conversion efficiency of the converter and the parasitic power of the water pump;

[0066] The actual value of net power is calculated as:

[0067]

[0068] Among them, P in formula (5) act Indicates the actual value of net power, I act Indicates the actual value of current, U act Indicates the actual value of voltage, η dcdc represents the transformation efficiency, P cmpr Indicates the parasitic power of the air compressor, P wp represents the parasitic power of the pump, and They respectively represent the filter functions corresponding to the parasitic power of the air compressor and the parasitic power of the water pump, and α1 and α2 respectively represent the filter parameters corresponding to the parasitic power of the air compressor and the parasitic power of the water pump.

[0069] Specifically, the air compressor parasitic power is the power consumed by the air compressor when it is working, and the water pump parasitic power is the power consumed by the water pump when it is working. Both are one of the main influencing factors of the fuel cell system. In order to avoid the net power output of the fuel cell engine being affected by the air compressor parasitic power and the water pump parasitic power, when calculating the net power request value, it is necessary to consider the consumption of the air compressor and the water pump operation, and calculate the expected net power after consuming the air compressor parasitic power and the water pump parasitic power. Among them, the water pump is one of the core components of the thermal management subsystem, which is used to control the temperature of the fuel cell stack so that the operating temperature of the fuel cell stack is in a relatively suitable range.

[0070] In one embodiment of the present invention, it is necessary to first perform noise filtering on the feedback signals related to the parasitic power of the air compressor and the parasitic power of the water pump to avoid electromagnetic interference noise. The filtering function used generally refers to a filtering algorithm with high-frequency noise filtering capability. This embodiment does not limit the filtering algorithm used.

[0071] Specifically, the net power request value of the fuel cell engine is determined by:

[0072] Obtain a power request value of the fuel cell system, a water temperature request value of the vehicle heating circuit, and a charging power limit value of the power battery; adjust the water temperature of the vehicle heating circuit based on the water temperature request value, and adjust the water temperature within a control range formed by a preset water temperature upper limit value and a preset water temperature lower limit value to generate heater parasitic power; add the heater parasitic power and the charging power limit value to determine the idle boundary power of the fuel engine; determine a net power request value based on a first comparison result of the power request value and the charging power limit value, and a second comparison result of the idle boundary power and the preset idle boundary setting value, so that the determined net power request value is less than or equal to the charging power limit value.

[0073] In one embodiment of the present invention, the power request value of the fuel cell system is the output power of the fuel cell system expected to be used for the entire vehicle with respect to the target vehicle, the actual water temperature value of the vehicle heating circuit represents the actual operating temperature of the fuel cell stack, the water temperature request value of the vehicle heating circuit represents the expected operating temperature of the fuel cell stack, and the charging power limit value of the power battery represents the maximum power that can be charged by the power battery.

[0074] In one embodiment of the present invention, the water temperature of the heating circuit of the whole vehicle is adjusted based on the water temperature request value, including: querying a preset first one-dimensional table according to the charging power limit value to determine the water temperature compensation value of the heating circuit of the whole vehicle, the preset first one-dimensional table including a mapping relationship between the charging power limit value and the water temperature compensation value, inputting the charging power limit value into the preset first one-dimensional table, and then querying and obtaining its corresponding water temperature compensation value; adding the water temperature compensation value and the water temperature request value to obtain the water temperature control request value; adjusting the water temperature of the heating circuit of the whole vehicle to the water temperature control request value.

[0075] In one embodiment of the present invention, the water temperature compensation value and the water temperature request value are added and the amplitude of the addition is limited by a limiter to limit the water temperature control request value, that is, the water temperature of the vehicle heating circuit within a water temperature control range defined by a preset water temperature upper limit value and a preset water temperature lower limit value, thereby maintaining the operating temperature of the fuel cell system of the target vehicle and avoiding the power battery, fuel cell stack and other components from being in an inappropriate low temperature environment when idling, resulting in low operating efficiency and affecting the power performance of the vehicle.

[0076] Through the above method, on the one hand, the net power of the fuel engine when idling can be quickly determined, which improves the response speed of the net power control. On the other hand, the water temperature will not drop too low during the idling of the fuel cell engine, thereby ensuring that the fuel cell stack has hydrothermal conditions for efficient electrochemical reactions. The power battery and fuel cell stack operate in a suitable temperature range, and the influence of the water temperature of the vehicle heating circuit and the parasitic power of the heater on the net power during heating is taken into account, with high calculation accuracy.

[0077] In one embodiment of the present invention, the actual water temperature of the vehicle heating circuit is controlled to the water temperature control request value by the heater, the power consumed by the heater during the water temperature adjustment is used as the heater parasitic power, and the sum of the charging power limit value and the heater parasitic power is used as the idle limit power of the fuel engine. In this way, the parasitic power consumed by the heater is considered in the process of calculating the net power, making the calculation more reliable and improving the accuracy of the idle control.

[0078] Wherein, determining the net power request value includes: if the power request value is less than or equal to the charging power limit value, the power request value is used as the power arbitration value of the engine; if the power request value is greater than the charging power limit value, the charging power limit value is used as the power arbitration value; if the idle boundary power is greater than or equal to the preset idle boundary setting value, any of the above power arbitration values ​​is used as the net power request value; if the idle boundary power is less than the preset idle boundary setting value, the idle boundary power is used as the net power request value. The preset idle boundary setting value can be adjusted according to actual conditions.

[0079] In one embodiment of the present invention, the parasitic power of the heater changes with the change of the water temperature. Therefore, the idle boundary power is a continuously changing value, and the idle boundary power can be quantified in stages.

[0080] In one embodiment of the present invention, since the power arbitration value of the fuel cell engine obtained by comparison is less than or equal to the charging power limit value of the power battery, when the idle boundary power is greater than or equal to the preset idle boundary setting value, the net power request value of the fuel cell engine will not be higher than the charging power limit value of the power battery, and since the heater consumes a portion of the parasitic power, the actual charging power of the power battery must be lower than the charging power limit value of the power battery, so as to avoid affecting the performance and service life of the power battery due to excessive charging power of the power battery, as well as safety problems caused by excessive charging power.

[0081] In one embodiment of the present invention, since the idle boundary power is obtained by adding the heater parasitic power and the charging power limit value, when the idle boundary power is less than the idle boundary setting value and the idle boundary power is used as the net power request value, the net power request value is as close to the idle boundary power as possible, that is, the net power request value is as close to the sum of the power battery charging power limit value and the heater parasitic power as possible. The heater parasitic power will gradually decrease as the actual water temperature of the vehicle heating circuit gradually approaches the water temperature control request value, and the net power request value will also decrease accordingly, thereby ensuring that the actual charging power of the power battery is always approximately equal to the charging power limit value; conversely, when the heater parasitic power increases, the net power request value will also increase accordingly, thereby ensuring that the actual charging power of the power battery is still as close to the charging power limit value as possible, so as to ensure that the power battery can be charged at the maximum chargeable power at low temperatures to generate heat, and accelerate the power battery to get rid of the unfavorable state of low chargeable power and limited chargeable power at low temperatures.

[0082] Step S220, taking the current request value as the adjustment target, dynamically adjust the current of the fuel cell stack to make it tend to the current request value, and determine the flow request value and pressure request value of the air entering the stack based on the currently adjusted current; at the same time, adjust the bypass throttle opening according to the currently adjusted current, and feed back the actual flow value and pressure value of the air entering the stack.

[0083] Specifically, adjusting the current of the fuel cell stack, that is, the actual current value, to the current request value is a dynamic and continuous process, that is, the flow request value and pressure request value of the air entering the stack change in real time with the current currently adjusted, that is, the real-time adjustment of the actual current value. The actual flow value and pressure actual value of the air entering the stack represent the actual flow value and pressure value when the air supply subsystem supplies air to the fuel cell stack, and the flow request value and pressure request value of the air entering the stack represent the flow value and pressure value when the air supply subsystem supplies air to the desired fuel cell stack.

[0084] In one embodiment of the present invention, the method for determining the flow request value and pressure request value of air thrust is: due to the currently adjusted current, the preset second one-dimensional table and the preset third one-dimensional table are respectively queried to obtain the flow request value and pressure request value of air thrust, the preset second one-dimensional table includes a mapping relationship between the current request value and the flow request value, and the preset third one-dimensional table includes a mapping relationship between the current request value and the pressure request value.

[0085] Specifically, adjusting the bypass throttle opening includes: obtaining the average voltage of the fuel cell stack and the actual value of the bypass throttle opening, the average voltage being obtained by weighted averaging the voltages of each single cell in the fuel cell stack, and the average voltage will change according to the current adjustment; calculating the bypass throttle opening request value according to the difference between the average voltage and a preset voltage upper limit value, the bypass throttle opening request value being within a control range formed by a preset opening upper limit value and a preset opening lower limit value; adjusting the bypass throttle opening by the bypass throttle opening request value so that the average voltage is less than or equal to the preset voltage upper limit value.

[0086] In one embodiment of the present invention, the average voltage of the fuel cell, that is, the weighted average value of the voltage of each single cell in the fuel cell stack will change in real time with the adjustment of the actual current value, that is, the change of the currently adjusted current, and the bypass throttle opening request value is calculated by the horizontal voltage and changes with the change of the horizontal voltage. Therefore, the bypass throttle opening changes in real time with the currently adjusted current, thereby ensuring the real-time idle control of the fuel cell system and improving the control response speed.

[0087] The bypass throttle opening request value is determined as follows:

[0088]

[0089] Among them, in formula (6) Indicates the bypass throttle opening request value, u act represents the average voltage, u lim Indicates the preset voltage upper limit, θ upper Indicates the preset upper limit of opening, θ lower Indicates the preset lower limit of opening. They are the proportional coefficient, integral coefficient and differential coefficient with respect to the average voltage respectively.

[0090] About the integral coefficient The specific calculation formula is:

[0091]

[0092] Among them, in formula (7) is the set integral coefficient value; θ upper Indicates the preset upper limit of opening, θ lower Indicates the preset lower limit of the opening.

[0093] In one embodiment of the present invention, adjusting the bypass throttle opening will affect the actual flow rate and pressure of air entering the stack. Therefore, it is necessary to feedback the actual value of the flow rate and pressure of air entering the stack after adjusting the bypass throttle opening.

[0094] By adjusting the bypass throttle opening in the above manner, the average voltage can be accurately controlled at or below the preset voltage upper limit, avoiding irreversible attenuation of the internal membrane electrode of the fuel cell stack when the fuel cell stack is operating at a high potential, thereby ensuring the performance and service life of the fuel cell stack.

[0095] In one embodiment of the present invention, the actual value of the air flow rate into the stack is Figure 1 2-Intake air mass flow sensor and Figure 1 9- The difference between the values ​​measured by the bypass mass flow sensor, the specific calculation formula is as follows:

[0096]

[0097] Among them, in formula (8) Indicates the actual value of air flow into the stack. 2- is the flow value measured by the intake mass flow sensor, is the flow value measured by the 9-bypass mass flow sensor, and They are filter functions of the sensor signals of the 2-intake mass flow sensor and the 9-bypass mass flow sensor, respectively. α1 and α2 are filter parameters of the sensor signals of the 2-intake mass flow sensor and the 9-bypass mass flow sensor, respectively.

[0098] Step S230, calculating according to the flow request value, the pressure request value, the actual flow value and the actual pressure value to obtain the speed request value and the back pressure throttle opening request value of the air compressor.

[0099] Specifically, determine the speed reference value of the air compressor and the opening reference value of the back-pressure throttle valve; perform difference operations on the flow request value and the actual flow value, and the pressure request value and the actual pressure value, respectively, to determine the flow control error and the pressure control error; perform decoupling operations on the flow control error and the pressure control error, respectively, to determine the speed compensation value of the air compressor and the opening compensation value of the back-pressure throttle valve; perform addition operations on the speed reference value and the speed compensation value of the air compressor, and the opening reference value and the opening compensation value of the back-pressure throttle valve, respectively, to obtain the speed request value and the back-pressure throttle valve opening request value.

[0100] The air compressor speed reference value and the back pressure throttle opening reference value are determined as follows:

[0101] The flow request value and the pressure request value are used to query the preset first feedforward table and the preset second feedforward table respectively to determine the speed reference value of the air compressor and the opening reference value of the back pressure throttle. The preset first feedforward table includes a mapping relationship between the flow request value, the pressure request value and the speed reference value, and the preset second feedforward table includes a mapping relationship between the flow request value, the pressure request value and the opening reference value of the back pressure throttle.

[0102] See also Figure 3 , is a schematic diagram of the decoupling control principle of the air supply subsystem according to an exemplary embodiment of the present invention. The air compressor and the back pressure throttle valve both belong to the air supply subsystem. Figure 3 As shown, the air inlet flow request value and the requested value of air inlet pressure p req After the rate limiter limits the rate of change, it is input into feedforward table 1 and feedforward table 2 (preset first feedforward table and preset second feedforward table) to obtain the speed reference value of the air compressor and the opening reference value of the back pressure throttle. and pressure control error e p The outputs of the two PID controllers are respectively input into two different PID (i.e., proportional, integral, differential) controllers, and then the outputs of the two PID controllers are input into the decoupler to obtain the speed compensation n of the air compressor. c and back pressure throttle opening compensation θ c ; Set the speed compensation value n c With speed reference value n ref Add together to get the air compressor speed request value n req , the back pressure throttle opening compensation amount θ c and the back pressure throttle opening reference value θ ref Add together to get the back pressure throttle opening request value θ req .

[0103] Step S240, controlling the air compressor speed and the back-pressure throttle opening according to the speed request value and the back-pressure throttle opening request value to complete the fuel cell system idle speed control.

[0104] Specifically, the speed of the air compressor is adjusted to the speed request value, and the opening of the back pressure throttle is adjusted to the back pressure throttle opening request value.

[0105] In one embodiment of the present invention, the speed of the air compressor is adjusted to the speed request value, and the opening of the back-pressure throttle is adjusted to the back-pressure throttle opening request value, so that the actual flow rate and pressure of air entering the stack, that is, after adjusting the bypass throttle opening, the feedback actual flow rate value and pressure actual value are adjusted to the flow rate request value and pressure request value of air entering the stack, so as to correct the error in the flow rate and pressure of air entering the stack caused by adjusting the bypass throttle opening.

[0106] Through the above method, the speed of the air compressor can be controlled based on adjusting the current of the fuel cell, so that the speed of the air compressor is maintained above the aerodynamic critical speed, avoiding that the air dynamic pressure bearing of the air compressor will not switch between the dynamic friction and static friction states when the fuel cell engine switches between the two operating states of idling and normal operation, so as to ensure that the wear of the air dynamic pressure bearing of the air compressor is minimized.

[0107] Specifically, after adjusting the air compressor speed and the back pressure throttle opening, it also includes:

[0108] The parasitic power of the air compressor is obtained, and the parasitic power of the air compressor is determined by adjusting the air compressor speed and the back pressure throttle opening; the actual value of the net power is recalculated according to the parasitic power of the air compressor to obtain an updated current request value; the current of the fuel cell stack is updated in real time until the currently adjusted current is equal to the updated current request value.

[0109] In one embodiment of the present invention, adjusting the air compressor speed and the back-pressure throttle opening will affect the parasitic power consumed by the air compressor. Therefore, it is necessary to calculate the parasitic power of the air compressor after adjusting the air compressor speed and the back-pressure throttle opening. Because the air compressor parasitic power is one of the calculation parameters of the net power request value of the battery engine, it is necessary to update the current request value of the fuel cell system to continuously control the idle speed of the fuel cell system, that is, repeat steps S210 to S240 to complete the idle speed control of the fuel cell system.

[0110] Through the above method, the net power request value of the fuel cell engine is recalculated according to the parasitic power of the air compressor to perform closed-loop control on the net power output of the fuel cell engine; the current request value is updated according to the recalculated net power request value, and the current of the fuel cell stack, that is, the actual current value, is adjusted in real time to form a closed-loop precise control of the current value output by the fuel cell stack; the average voltage of the fuel cell stack changes with the actual value of the circuit currently adjusted, and the bypass throttle opening is readjusted according to the average voltage after the change to form a closed-loop control of the average voltage and bypass throttle opening of the fuel cell stack; based on the current actual value of the current adjustment, a new flow request value and a new pressure request value are determined, and the air compressor speed and the back pressure throttle opening are controlled again according to the new flow request value and the new pressure request value to form a closed-loop control of the flow and pressure of air entering the stack, the air compressor speed, and the back pressure throttle opening. Based on this, the various parameters involved in the idle operation of the fuel cell system are continuously updated in a cycle, and the closed-loop precise control during the idle operation of the fuel cell system is realized, and the closed-loop control has high accuracy and real-time performance.

[0111] In one embodiment of the present invention, after the fuel cell system of the target vehicle enters idle operation, it also includes: if a shutdown signal is received from the target vehicle, the fuel cell system idle control is turned off, and the operating parameters of the fuel cell system idle control when the target vehicle is shut down are saved, and the operating parameters include the current of the fuel cell stack, the bypass throttle opening, the air compressor speed and the back pressure throttle opening.

[0112] In one embodiment of the present invention, when the target vehicle is in a shutdown state, the fuel cell system is stopped from being idle controlled, so as to save energy and protect the environment. The operating parameters also include parameters such as the net power of the engine, the flow rate and pressure of the air entering the stack, etc.

[0113] Through the above method, factors such as the voltage of the fuel cell stack, the flow and pressure of air entering the stack, and the water temperature of the vehicle heating circuit are taken into consideration, and the conditions required for the efficient operation of the fuel cell stack are met, such as controlling the water temperature so that the fuel cell stack operates at an appropriate temperature, keeping the voltage stable, and timely air supply, etc., to ensure efficient material transmission and electrochemical reaction conditions inside the fuel cell engine, so that when the fuel cell engine recovers from idling to power output, it can immediately withstand rapid loading, and the fuel cell stack does not have a single cell voltage that is too low, and has better dynamic response performance. Based on this, the reliability and accuracy of the idle speed control of the fuel cell system are improved.

[0114] See also Figure 4 , is a schematic diagram of the overall framework of the idle speed control function of a fuel cell system according to an exemplary embodiment of the present invention. Figure 4As shown in FIG. 1 , the functions implemented by the fuel cell system idle speed control method can be divided into four modules, including: an engine net power request value calculation module, an engine net power actual value calculation module, an engine net power closed-loop control module, an idle speed average cell voltage control module, and an air supply pressure flow closed-loop decoupling control module. Among them, the engine net power request value calculation module is used to calculate the engine net power request value according to the charging power limit value P chg and the power request value P of the fuel cell system veh Calculate the net power request value P of the fuel cell engine req , the net power request value P req Input to the engine net power closed-loop control module; the engine net power actual value calculation module is used to calculate the actual current value I act , Actual voltage value U act , conversion efficiency η dcdc , air compressor parasitic power P cmpr and the pump parasitic power P wp Calculate the actual net power value P of the fuel cell engine act , the actual value of net power P act Input to the engine net power closed-loop control module; the engine net power closed-loop control module is used to control the net power request value P according to the net power request value P req and the actual value of net power P act Calculate the current request value I req , the actual current value I act Closed loop control to request value I req , where the average voltage u act Will respond to changes in current.

[0115] Continue to refer to Figure 4 , air supply pressure flow closed-loop decoupling control module, used to adjust the current request value I req Adjusted current actual value I act Query the preset second one-dimensional table and the preset third one-dimensional table respectively to obtain the air flow request value into the stack And the required value of air pressure entering the stack p req ; According to the traffic request value and actual flow value Calculate the air flow control error into the reactor According to the pressure request value p req and the actual pressure value p act Calculate the pressure control error e of air entering the pile p ; Then the traffic request value Pressure request value p req , flow control error Pressure control error p Input to the air supply system decoupling control strategy, that is, implementation Figure 3 The calculation of decoupling control of the air supply subsystem in the process is used to determine the air compressor speed request value n. req and back pressure throttle opening request value θ req To make the air compressor speed reach the speed request value n req , the back pressure throttle opening reaches the back pressure throttle opening request value θ req When the compressor speed and back pressure throttle opening are controlled to change, the actual value of the air flow into the stack and the actual pressure value p act Will respond to changes and adjust to the traffic request value and pressure request value p req .

[0116] Continue to refer to Figure 4 , idle average single cell voltage control module, used to control the average voltage u act and the preset voltage upper limit u lim Calculate bypass throttle opening request value By controlling the bypass throttle valve opening to the bypass throttle valve opening request value This operation will affect the actual value of the air flow into the pile and the actual pressure value p act This impact will be fed back to the air supply pressure flow closed-loop decoupling control module for correction.

[0117] See also Figure 5 , is a schematic diagram of the overall logic of the idle speed control of a fuel cell system according to an exemplary embodiment of the present invention. Figure 5 As shown, when the fuel cell system enters idle operation, the net power request value of the fuel cell engine is first calculated according to the water temperature request value of the vehicle heating circuit and the power request value of the fuel cell system; the net power actual value of the fuel cell engine is calculated according to the current actual value, the voltage actual value, the conversion efficiency, the air compressor parasitic power and the water pump parasitic power; the current request value is calculated according to the net power request value and the net power actual value, and the current actual value is closed-loop controlled to the request value through DCDC; then, according to the actual current value, the table is looked up, that is, the preset second one-dimensional table and the preset third one-dimensional table are used to determine the flow request value of air entering the stack And the required value of air pressure entering the stack p req , so that the pressure and flow rate of air entering the stack are adjusted to the flow request value and pressure request value p req , resulting in the air compressor parasitic power P cmpr changes, returns to the actual value of the calculated current I act At the same time, the bypass throttle opening request value is calculated according to the average voltage and the preset voltage upper limit value, and the bypass throttle opening is closed-loop controlled to the bypass throttle opening request value And feedback adjustment. In the above process, if a shutdown signal is received, the machine is shut down, otherwise the above steps are executed cyclically. It should be understood that the specific calculation details have been described in the above embodiment and will not be repeated here.

[0118] See also Figure 6(a) to Figure 6(g) It is a schematic diagram of the idle speed control effect of the fuel cell system shown in an exemplary embodiment of the present invention. When the fuel cell system is idling, the net power gradually decreases from 5kW at the beginning to 1kW, and the bypass throttle valve will gradually open, that is, the opening of the bypass throttle valve is controlled to gradually increase. Due to the decrease in the inlet pressure and flow of the fuel cell stack caused by the increase in the opening of the bypass throttle valve, that is, the decrease in the flow and pressure of the air entering the stack, it is necessary to increase the speed of the air compressor to compensate for the decreased flow and pressure of the air entering the stack, otherwise the actual flow and pressure of the air entering the stack cannot be maintained at the flow request value and pressure request. Therefore, through the adaptive coordinated control of the air compressor speed and the back pressure throttle valve opening, the flow and pressure of the air entering the stack are stably maintained at the flow request value and pressure request, respectively, to ensure efficient material reaction conditions of the fuel cell stack. However, since increasing the speed of the air compressor will increase the power of the accessories, the average voltage of the fuel cell stack will fluctuate, affecting the performance and service life of the fuel cell stack. Therefore, it is necessary to adjust the bypass throttle opening at the same time to stabilize the average voltage at a preset voltage upper limit, i.e., 0.85V in Figure 6(b). In this way, when the fuel cell engine is idling, the net power of the fuel engine and the horizontal voltage of the fuel cell stack can be accurately controlled, and the conditions for efficient operation of the fuel cell stack and the performance and service life of the fuel cell stack can be guaranteed.

[0119] In one embodiment of the present invention, the following preparations may be made for implementing the fuel cell system idle speed control method:

[0120] First, based on Figure 1 The structure shown builds a fuel cell engine with various subsystems and control functions, including a fuel cell stack, an air supply subsystem, a hydrogen supply subsystem, a thermal management subsystem, a DCDC and a fuel cell control unit (FCCU);

[0121] Second, configure the CAN (Controller Area Network) communication protocol between DCDC and FCCU to ensure that DCDC can receive the DCDC input terminal current request value signal sent by FCCU, and at the same time FCCU can receive the DCDC output terminal current actual value and voltage actual value signal sent by DCDC;

[0122] Third, configure the CAN communication protocol between the fuel cell single-chip voltage monitor (CVM) and the FCCU so that the FCCU can receive the average voltage data sent by the CVM;

[0123] Fourth, connect the completed fuel cell engine to the test bench, connect the hydrogen inlet solenoid valve inlet pipeline of the fuel cell engine to the hydrogen supply pipeline of the test system, and connect the main water circuit and auxiliary water circuit to the cooling water circuit of the test system to ensure continuous hydrogen supply and cooling water circulation during the operation of the fuel cell engine;

[0124] Fifth, an application layer software model corresponding to the idle speed control method of the fuel cell system can be established in Matlab / Simulink (a data processing and algorithm design tool) and downloaded to the FCCU;

[0125] Sixth, supply high and low voltage power to the fuel cell engine through the test bench, open the test bench hydrogen supply circuit and cooling water supply circuit, and then request the fuel cell engine to start through INCA (i.e., the vehicle calibration tool), and then request the net power of the fuel cell engine through INCA to start the fuel cell system idle control.

[0126] In addition, after the fuel cell system idle speed control is turned on, the relevant parameters of the fuel cell system operation are sampled and saved.

[0127] See also Figure 7 , is a block diagram of a fuel cell system idle speed control device according to an exemplary embodiment of the present invention. Figure 7 As shown, the exemplary fuel cell system idle speed control device includes: an acquisition module 710 , a dynamic adjustment module 720 , a calculation module 730 and a control module 740 .

[0128] The acquisition module 710 is used to acquire the current request value of the fuel cell stack in the fuel cell system when the fuel cell system of the target vehicle enters the idle operation;

[0129] The dynamic adjustment module 720 is used to dynamically adjust the current of the fuel cell stack to make it tend to the current request value with the current request value as the adjustment target, determine the flow request value and pressure request value of the air entering the stack based on the current adjustment current; at the same time, adjust the bypass throttle opening according to the current adjustment current, and feed back the actual flow value and pressure value of the air entering the stack;

[0130] A calculation module 730, configured to calculate according to the flow request value, the pressure request value, the flow actual value and the pressure actual value to obtain a speed request value and a back pressure throttle opening request value of the air compressor;

[0131] The control module 740 is used to control the air compressor speed and the back-pressure throttle opening according to the speed request value and the back-pressure throttle opening request value to complete the idle speed control of the fuel cell system.

[0132] In one embodiment of the present invention, the function of the acquisition module in the fuel cell system idle speed control device can be as follows: Figure 4 The oil engine net power closed-loop control module shown in the figure is realized; the functions of the dynamic adjustment module, the calculation module and the control module can be Figure 4 The idle average cell voltage control module and the air supply pressure flow closed-loop decoupling control module are implemented.

[0133] It should be noted that the fuel cell system idle speed control device provided in the above embodiment and the fuel cell system idle speed control method provided in the above embodiment belong to the same concept, wherein the specific manner of executing the operation of each step has been described in detail in the system embodiment and will not be repeated here.

[0134] An embodiment of the present invention also provides an electronic device, comprising: one or more processors; a storage device for storing one or more programs, when the one or more programs are executed by one or more processors, the electronic device implements the fuel cell system idle control method provided in the above-mentioned embodiments.

[0135] See also Figure 8 , shows a schematic diagram of the structure of a computer system suitable for implementing an electronic device of an embodiment of the present invention. It should be noted that, Figure 8 The computer system 800 of the electronic device shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present invention.

[0136] like Figure 8 As shown, the computer system 800 includes a central processing unit (CPU) 801, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 802 or the program loaded from the storage part 808 to the random access memory (RAM) 803, such as executing the method in the above embodiment. In the RAM 803, various programs and data required for system operation are also stored. The CPU 801, ROM 802 and RAM 803 are connected to each other through a bus 804. The input / output (I / O) interface 805 is also connected to the bus 804.

[0137] The following components are connected to the I / O interface 805: an input section 806 including a keyboard, a mouse, etc.; an output section 807 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker; a storage section 808 including a hard disk, etc.; and a communication section 809 including a network interface card such as a LAN (Local Area Network) card, a modem, etc. The communication section 809 performs communication processing via a network such as the Internet. A drive 810 is also connected to the I / O interface 805 as needed. A removable medium 811, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 810 as needed so that a computer program read therefrom is installed into the storage section 808 as needed.

[0138] In particular, according to an embodiment of the present invention, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present invention includes a computer program product, which includes a computer program carried on a computer readable medium, and the computer program includes a computer program for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication section 809, and / or installed from a removable medium 811. When the computer program is executed by a central processing unit (CPU) 801, various functions defined in the system of the present invention are executed.

[0139] The embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor of a computer, the computer executes the aforementioned fuel cell system idle speed control method. The computer-readable storage medium may be included in the electronic device described in the above embodiment, or may exist independently without being assembled into the electronic device.

[0140] It should be noted that the computer-readable medium shown in the embodiment of the present invention may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium may be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present invention, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable computer program. This propagated data signal may take a variety of forms, including but not limited to an electromagnetic signal, an optical signal, or any suitable combination of the above. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium, which may send, propagate or transmit a program for use by or in conjunction with an instruction execution system, apparatus or device. A computer program contained on a computer-readable medium may be transmitted using any appropriate medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0141] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present invention. Among them, each box in the flowchart or block diagram can represent a module, a program segment, or a part of the code, and the above-mentioned module, program segment, or a part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart, can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0142] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A fuel cell system idle speed control method, characterized in that: include: When the fuel cell system of the target vehicle enters idle operation, obtaining a current request value of a fuel cell stack in the fuel cell system; Taking the current request value as the adjustment target, dynamically adjusting the current of the fuel cell stack to make it tend to the current request value, determining the flow request value and pressure request value of air entering the stack based on the current adjusted current; at the same time, adjusting the bypass throttle opening according to the current adjusted current, and feeding back the actual flow value and pressure value of the air entering the stack; Calculating according to the flow request value, the pressure request value, the flow actual value and the pressure actual value to obtain a speed request value and a back pressure throttle opening request value of the air compressor; Controlling the air compressor speed and the back-pressure throttle opening according to the speed request value and the back-pressure throttle opening request value to complete the fuel cell system idle speed control; Before obtaining the current request value of the fuel cell stack in the fuel cell system, the method further includes: Obtaining a net power request value and a net power actual value of an engine in the fuel cell system; The current request value of the fuel cell stack is calculated according to the net power request value and the net power actual value; wherein, Calculating a difference between the actual net power value and the requested net power value to determine a net power error; According to the actual value of the net power, a preset control parameter calibration table is searched to determine a proportional coefficient, an integral coefficient and a differential coefficient related to the net power of the engine; The net power error is added to the calculated values ​​of the proportional coefficient, the integral coefficient, and the differential coefficient of the engine net power to determine the current request value.

2. The fuel cell system idle speed control method according to claim 1, characterized in that: The controlling of the air compressor speed and the back pressure throttle opening according to the speed request value and the back pressure throttle opening request value comprises: Determining a speed reference value of the air compressor and an opening reference value of the back pressure throttle; Performing difference calculation on the flow request value and the actual flow value, and on the pressure request value and the actual pressure value, respectively, to determine a flow control error and a pressure control error; Decoupling the flow control error and the pressure control error respectively to determine a speed compensation value of the air compressor and an opening compensation value of the back pressure throttle; Respectively adding the speed reference value and the speed compensation value of the air compressor, and the opening reference value and the opening compensation value of the back-pressure throttle to obtain a speed request value and a back-pressure throttle opening request value; The rotation speed of the air compressor is adjusted to the rotation speed request value, and the opening of the back pressure throttle is adjusted to the back pressure throttle opening request value.

3. The fuel cell system idle speed control method according to claim 1, characterized in that: The step of adjusting the bypass throttle valve opening comprises: Obtaining an average voltage of the fuel cell stack and an actual value of the bypass throttle valve opening, wherein the average voltage is obtained by weighted average calculation of the voltages of the individual cells in the fuel cell stack, and the average voltage changes according to the current adjustment; Calculating the bypass throttle valve opening request value according to the difference between the average voltage and a preset voltage upper limit value, wherein the bypass throttle valve opening request value is within a control range formed by a preset opening upper limit value and a preset opening lower limit value; The bypass throttle opening is adjusted according to the bypass throttle opening request value so that the average voltage is less than or equal to the preset voltage upper limit value.

4. The fuel cell system idle speed control method according to claim 1, characterized in that: The current request value is within a control range formed by a preset current upper limit value and a preset current lower limit value.

5. The fuel cell system idle speed control method according to claim 1, characterized in that: After controlling the air compressor speed and the back pressure throttle opening according to the speed request value and the back pressure throttle opening request value, the method further includes: Obtaining the parasitic power of the air compressor, wherein the parasitic power of the air compressor is determined by adjusting the speed of the air compressor and the opening of the back pressure throttle; recalculating the net power actual value according to the parasitic power of the air compressor to obtain the updated current request value; The current of the fuel cell stack is updated in real time until the currently adjusted current is equal to the updated current request value.

6. The fuel cell system idle speed control method according to claim 5, characterized in that: Before obtaining the net power request value and the net power actual value of the engine in the fuel cell system, the method further includes: Acquiring the actual current value and voltage value of the fuel cell stack, the conversion efficiency of the converter and the parasitic power of the water pump; The calculation formula of the actual value of the net power is: Among them, P act Indicates the actual value of the net power, I act Indicates the actual value of the current, U act represents the actual value of the voltage, η dcdc represents the conversion efficiency, P cmpr represents the parasitic power of the air compressor, P wp represents the parasitic power of the water pump, and They respectively represent the filter functions corresponding to the parasitic power of the air compressor and the parasitic power of the water pump, and α1 and α2 respectively represent the filter parameters corresponding to the parasitic power of the air compressor and the parasitic power of the water pump.

7. The fuel cell system idle speed control method according to claim 1, characterized in that: Before calculating the current request value of the fuel cell stack according to the net power request value and the net power actual value, the method further includes: Obtaining a power request value of the fuel cell system, a water temperature request value of the vehicle heating circuit, and a charging power limit value of the power battery; Adjusting the water temperature of the vehicle heating circuit based on the water temperature request value, wherein the water temperature is adjusted within a control range formed by a preset water temperature upper limit value and a preset water temperature lower limit value to generate heater parasitic power; determining an idle boundary power of the fuel engine according to the heater parasitic power and the charging power limit value; The net power request value is determined based on a first comparison result between the power request value and the charging power limit value and a second comparison result between the idle boundary power and a preset idle boundary setting value, so that the determined net power request value is less than or equal to the charging power limit value.

8. The fuel cell system idle speed control method according to claim 7, characterized in that: The determining the net power request value according to a first comparison result between the power request value and the charging power limit value, and a second comparison result between the idle boundary power and a preset idle boundary setting value, comprises: If the power request value is less than or equal to the charging power limit value, the power request value is used as the power arbitration value of the engine; If the power request value is greater than the charging power limit value, the charging power limit value is used as the power arbitration value; If the idle boundary power is greater than or equal to the preset idle boundary setting value, any of the above power arbitration values ​​is used as the net power request value; If the idle boundary power is less than the preset idle boundary setting value, the idle boundary power is used as the net power request value.

9. The fuel cell system idle speed control method according to claim 7, characterized in that: The step of adjusting the water temperature of the vehicle heating circuit based on the water temperature request value includes: According to the charging power limit value, a preset first one-dimensional table is searched to determine a water temperature compensation value of the vehicle heating circuit; Adding the water temperature compensation value and the water temperature request value to obtain a water temperature control request value; The water temperature of the vehicle heating circuit is adjusted to the water temperature control request value.

10. The fuel cell system idle speed control method according to any one of claims 1 to 9, characterized in that: After the fuel cell system of the target vehicle enters idle operation, the method further includes: If a shutdown signal is received from the target vehicle, the fuel cell system idle control is turned off, and the operating parameters of the fuel cell system idle control when the target vehicle is shut down are saved, the operating parameters including the current of the fuel cell stack, the bypass throttle opening, the air compressor speed and the back pressure throttle opening.

11. A fuel cell system idle speed control device, characterized in that: include: An acquisition module, used for acquiring a current request value of a fuel cell stack in the fuel cell system when the fuel cell system of the target vehicle enters an idle operation; a dynamic adjustment module, for dynamically adjusting the current of the fuel cell stack to make it tend to the current request value with the current request value as the adjustment target, determining the flow request value and pressure request value of air entering the stack based on the current currently adjusted current; at the same time, adjusting the bypass throttle opening according to the current adjusted current, and feeding back the actual flow value and pressure value of the air entering the stack; A calculation module, configured to calculate according to the flow request value, the pressure request value, the flow actual value and the pressure actual value to obtain a speed request value and a back pressure throttle opening request value of the air compressor; A control module, used for controlling the air compressor speed and the back-pressure throttle opening according to the speed request value and the back-pressure throttle opening request value, so as to complete the idle speed control of the fuel cell system; Before obtaining the current request value of the fuel cell stack in the fuel cell system, the method further includes: Obtaining a net power request value and a net power actual value of an engine in the fuel cell system; The current request value of the fuel cell stack is calculated according to the net power request value and the net power actual value; wherein, Calculating a difference between the actual net power value and the requested net power value to determine a net power error; According to the actual value of the net power, a preset control parameter calibration table is searched to determine a proportional coefficient, an integral coefficient and a differential coefficient related to the net power of the engine; The net power error is added to the calculated values ​​of the proportional coefficient, the integral coefficient, and the differential coefficient of the engine net power to determine the current request value.

12. An electronic device, characterized in that: include: one or more processors; A storage device for storing one or more programs, when the one or more programs are executed by the one or more processors, enables the electronic device to implement the fuel cell system idle speed control method as described in any one of claims 1 to 10.

13. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and the computer program is used to enable a computer to execute the fuel cell system idle speed control method according to any one of claims 1 to 10.

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