A fuel cell vehicle stack power reconstruction method and device based on Chinese operating conditions

Abstract

The present invention discloses a fuel cell vehicle stack power reconstruction method based on Chinese operating conditions, including the following steps: the first step is to obtain the required power of the whole vehicle power system of the fuel cell vehicle based on the vehicle power balance equation; the second step is to analyze the fuel cell vehicle energy management strategy to obtain the fuel cell system correction power; the third step is to sum the required power of the whole vehicle power system and the fuel cell system correction power to obtain the fuel cell stack power of the fuel cell vehicle. In addition, the present invention also discloses a fuel cell vehicle stack power reconstruction device based on Chinese operating conditions. The present invention can reconstruct the equivalent fuel cell stack power operating condition according to the speed operating condition of the fuel cell vehicle, thereby providing an experimental basis for the formulation of the fuel cell vehicle energy management strategy and durability evaluation.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cell vehicles, and in particular to a method and device for reconstructing the power of a fuel cell vehicle stack based on Chinese operating conditions. Background Art

[0002] At present, the basic working principle of fuel cell vehicles is: hydrogen and oxygen undergo electrochemical reactions to generate water and release energy. It has the advantages of zero pollution, high efficiency, and high energy density, and has received attention from governments and companies around the world.

[0003] The power unit of a fuel cell vehicle consists of two parts: a fuel cell and a power battery. During its operation, both parts can provide power for the vehicle. During the actual operation of a fuel cell vehicle, the reasonable distribution of the power of these two power units has an important impact on the economy and power of the vehicle. In order to better meet the vehicle's power and improve its economy, fuel cell vehicles have adopted certain energy management strategies to complete the power distribution of the power unit.

[0004] In the development process of fuel cell vehicles, traditional operating condition tests are based on speed-time conditions to test vehicle performance. Currently, there is no technology that can provide a more direct power-time condition for the development and verification test of fuel cell vehicles as a basis for development tests. Summary of the invention

[0005] The purpose of the present invention is to provide a method and device for reconfiguring the power of a fuel cell vehicle stack based on Chinese operating conditions in order to address the technical defects of the prior art.

[0006] To this end, the present invention provides a fuel cell vehicle stack power reconstruction method based on Chinese operating conditions, wherein the fuel cell vehicle includes two power devices, a fuel cell and a power battery, and the method includes the following steps:

[0007] The first step is to calculate the required power of the fuel cell vehicle's power system based on the vehicle power balance equation;

[0008] The second step is to analyze the energy management strategy of the fuel cell vehicle. When the energy management strategy of the fuel cell vehicle adopts the power following strategy, the specific analysis operation is: obtain the real-time state of charge SOC of the power battery of the fuel cell vehicle, and pre-set the maximum value and the minimum value of the state of charge SOC of the power battery, and then obtain the fuel cell system correction power based on the preset fuel cell system correction power calculation formula;

[0009] The third step is to sum the vehicle power system demand power obtained in the first step and the fuel cell system correction power obtained in the second step to obtain the fuel cell stack power of the fuel cell vehicle, that is, the fuel cell system output power.

[0010] It can be seen from the technical solution provided by the present invention that, compared with the prior art, the present invention provides a method and device for reconstructing the power of a fuel cell vehicle stack based on Chinese operating conditions. The method and device are scientifically designed and can reconstruct the equivalent fuel cell stack power (i.e., the output power of the fuel cell system) operating conditions according to the speed operating conditions of the fuel cell vehicle, thereby providing a basis for various tests of fuel cell vehicles and having great practical significance.

[0011] By applying the present invention, it can be used to construct a fuel cell stack power condition that conforms to China's operating conditions, realize the reconstruction of the fuel cell vehicle stack power condition based on China's operating conditions, and then be used to provide guidance for fuel cell engine calibration tests, fuel cell vehicle energy management strategy formulation and development, fuel cell vehicle durability test evaluation, etc. It has the advantages of strong operability and clear goals, which is conducive to improving the energy utilization rate of fuel cell vehicles and promoting the development of their technology.

[0012] The present invention utilizes the existing vehicle speed-time curve of China's operating conditions, obtains the vehicle acceleration-time curve by differentiation, and then obtains the vehicle power system demand power at different speeds based on the vehicle power balance equation. Combined with a specially formulated power allocation strategy for fuel cell vehicles, the fuel cell stack power (i.e., fuel cell system output power) operating condition curve is finally reconstructed by judging parameters such as the vehicle's SOC and speed.

[0013] The present invention can realize the reconstruction of the fuel cell vehicle stack power condition based on the Chinese working condition, and solve the problem of converting the fuel cell vehicle "speed-time" working condition to the "stack power-time" working condition. The conversion method of the two working conditions is given, thereby providing guidance for the relevant research and development technology of fuel cell vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A flow chart of a fuel cell vehicle stack power reconstruction method based on Chinese operating conditions provided by the present invention;

[0015] Figure 2 A schematic diagram of a working condition curve of the power requirement of a fuel cell vehicle power system based on Chinese working conditions obtained based on a fuel cell vehicle stack power reconstruction method based on Chinese working conditions provided by the present invention;

[0016] Figure 3A fuel cell vehicle stack power reconstruction method based on Chinese operating conditions provided by the present invention, and a basic calculation flow chart of the fuel cell vehicle stack power obtained based on the power following strategy;

[0017] Figure 4 A structural block diagram of a fuel cell vehicle stack power reconstruction device based on Chinese operating conditions provided by the present invention. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and implementation modes.

[0019] See also Figure 1 The present invention provides a fuel cell vehicle stack power reconstruction method based on Chinese operating conditions. The fuel cell vehicle includes two power devices, a fuel cell and a power battery. The method specifically includes the following steps:

[0020] The first step is to calculate the required power of the fuel cell vehicle's power system based on the vehicle power balance equation;

[0021] The second step is to analyze the fuel cell vehicle energy management strategy. When the fuel cell vehicle energy management strategy adopts the power following strategy, the specific analysis operation is: obtain the real-time state of charge SOC (i.e., current SOC) of the power battery of the fuel cell vehicle, and pre-set the maximum value and minimum value of the state of charge SOC of the power battery, and then obtain the fuel cell system correction power based on the preset fuel cell system correction power (i.e., fuel cell stack power) calculation formula;

[0022] The third step is to sum the vehicle power system demand power obtained in the first step and the fuel cell system correction power obtained in the second step to obtain the fuel cell stack power of the fuel cell vehicle, that is, the fuel cell vehicle stack power, that is, the fuel cell system output power.

[0023] It should be noted that before the present invention was proposed, the fuel cell stack power (fuel cell system output power) of existing fuel cell vehicles was calculated by measuring current-voltage during the test process, and it was necessary to obtain it through actual tests. The fuel cell stack power (fuel cell system output power) of the fuel cell vehicle proposed in the present invention is reconstructed based on the vehicle speed condition when no operating condition test is performed, and can be used as a test basis.

[0024] In the present invention, after the third step, the following steps are also included:

[0025] The fourth step is to redraw (i.e., reconstruct) the fuel cell stack power curve of the fuel cell vehicle, using the fuel cell stack power of the fuel cell vehicle obtained in the third step as the vertical coordinate and the driving time of the fuel cell vehicle corresponding to the fuel cell stack power of the fuel cell vehicle as the horizontal coordinate.

[0026] In the present invention, after the third step, the following steps are also included:

[0027] See also Figure 3 As shown, in the fifth step, the average of the preset maximum state of charge SOC value and the preset minimum state of charge SOC value of the power battery is subtracted from the real-time state of charge SOC (i.e., the current SOC) of the power battery of the fuel cell vehicle. If the difference obtained is greater than zero, the first power output mode is executed; if the difference obtained is less than zero, the second power output mode is executed;

[0028] The first power output mode is specifically: controlling the fuel cell to discharge and the power battery to charge, that is, the total output power of the fuel cell vehicle is provided by the fuel cell alone;

[0029] The second power output mode is specifically: controlling the fuel cell and the power battery to discharge simultaneously, that is, the fuel cell and the power battery together provide the total output power of the fuel cell vehicle.

[0030] It should be noted that if the obtained difference is equal to zero, the first power output mode is also executed.

[0031] It should be noted that, for the present invention, through the fifth step above, reconstruction of the speed condition of the fuel cell vehicle to the power condition of the stack can be achieved, thereby providing a basis for relevant tests of the fuel cell vehicle.

[0032] In the first step, the vehicle speed-time curve of the existing Chinese working conditions is used to calculate the required power of the fuel cell vehicle's power system based on the vehicle power balance equation.

[0033] It should be noted that the existing vehicle speed-time curve of the Chinese operating conditions may be the vehicle driving condition curve recorded in the existing national standard documents, for example, it may be the CLTC-P condition (i.e., China's light-duty passenger car driving condition) curve recorded in "GB / T 38146.1-2019 China Automobile Driving Conditions Part 1: Light Vehicles". This curve uses the vehicle speed as the vertical coordinate and the vehicle driving time as the horizontal coordinate, showing the corresponding relationship between the vehicle speed and the vehicle driving time.

[0034] In the present invention, the common Chinese operating condition curve of existing vehicles is a "speed-time" curve, where the ordinate is the vehicle speed and the abscissa is time, which reflects the law of change of the vehicle's driving speed over time. It is obtained based on the Chinese urban operating conditions, from which the vehicle's speed at different times can be obtained. This "speed-time" curve can provide a basis for vehicle speed for vehicle testing. For example, when assessing fuel consumption data, traditional vehicles can drive at the speed specified in this operating condition to measure the fuel consumption. For the "speed-time" curve, the vehicle's abscissa represents time, in seconds; the ordinate represents vehicle speed, in km / h.

[0035] It should also be noted that there are many kinds of vehicle operating curves, such as the Chinese operating condition, the American UDDS operating condition, and the European NEDC operating condition, all of which represent the relationship between vehicle speed and time. This operating condition is obtained based on the statistics of urban vehicle operation in different regions and is used for various vehicle tests. In the present invention, the Chinese operating condition is taken as an example, and the proposed fuel cell stack power reconstruction method is applicable to any vehicle speed-time operating condition.

[0036] In the first step, in terms of specific implementation, according to automobile theory, the vehicle power balance equation is as follows:

[0037]

[0038] In formula (1), P e The power required by the fuel cell vehicle's power system; η T is the vehicle transmission efficiency; G is the vehicle gravity; f is the rolling resistance coefficient; i is the slope; C D is the air resistance coefficient; A is the frontal area of ​​the vehicle; σ is the rotational mass conversion coefficient; m is the vehicle mass; v is the vehicle speed, and t is the vehicle travel time. It should be noted that the various parameters in formula (1) should be obtained based on the specific structure and size of the vehicle, or by referring to the relevant performance manual of the vehicle.

[0039] In terms of specific implementation, taking a light passenger car as an example, according to the CLTC-P operating condition (i.e., China's light passenger car driving condition) curve recorded in "GB / T 38146.1-2019 China Automobile Driving Condition Part 1: Light Vehicles" (this curve is a vehicle speed-time curve, which is an existing vehicle speed-time curve of the Chinese operating condition), the acceleration-time operating condition can be obtained by differentiating the speed with respect to time. Substituting the obtained acceleration and speed into the power balance equation of the vehicle, the required power of the vehicle power system can be obtained, and then the required power-time operating condition curve of the vehicle power system can be obtained, such as Figure 2 shown.

[0040] It should be noted that for fuel cell vehicles, their power unit includes two parts: a fuel cell and a power battery. During its operation, both parts can provide power for the vehicle. In order to better meet the vehicle's dynamics and improve economy, fuel cell vehicles have adopted certain energy management strategies to complete the power distribution of the power unit. Therefore, for the present invention, when constructing the fuel cell stack power condition, power decomposition is completed according to the vehicle energy management strategy, and then the fuel cell stack power condition is obtained. Taking the mainstream energy management strategy of full-power fuel cell vehicles-the power following strategy as an example, a method for calculating the power of the fuel cell stack is given, as follows:

[0041] In the second step, the preset fuel cell system correction power (i.e. fuel cell correction stack power) P cor The calculation formula is as follows:

[0042]

[0043] In formula (2), c is a correction coefficient, which is greater than zero; hi_soc is a preset maximum state of charge SOC value of the power battery; lo_soc is a preset minimum state of charge SOC value of the power battery; and SOC is the real-time state of charge SOC of the power battery (i.e., current SOC).

[0044] It should be noted that the parameters in formula (2) mainly involve the power battery SOC, which represents the percentage of power. The correction coefficient c depends on the energy management strategy of the fuel cell vehicle and needs to be analyzed and calibrated based on the strategy. The correction coefficient c has no fixed value range and needs to be determined based on the manufacturer's strategy analysis.

[0045] In the present invention, the fuel cell stack power of a fuel cell vehicle is the fuel cell vehicle stack power, that is, the required fuel cell system output power.

[0046] In the present invention, the power device of the fuel cell vehicle includes two parts: a fuel cell (i.e., a fuel cell stack) and a power battery. The total output power of a fuel cell vehicle means: the power of the fuel cell vehicle providing power to the outside when it is running; the power of the power battery means: the external output power of the power battery, which is equal to the current multiplied by the voltage of the power battery; the power of the fuel cell stack of the fuel cell vehicle is equal to the voltage of the stack multiplied by the current of the stack. The total output power of a fuel cell vehicle is equal to the sum of the power of the fuel cell stack and the power of the power battery.

[0047] It should be noted that, in the present invention, the power of the power battery is reflected in the correction of the output power of the fuel cell system, which is specifically reflected in formula (2), and the power of the fuel cell stack is corrected according to the power battery SOC.

[0048] During the operation of a fuel cell vehicle, the fuel cell stack outputs power to the outside. Depending on the power requirements of the entire vehicle, sometimes the fuel cell stack and the power battery output power together, and sometimes the fuel cell stack outputs power alone, and part of the power is used to charge the power battery.

[0049] In the third step, the fuel cell stack power (fuel cell system output power) P fc The calculation formula is as follows:

[0050] P fc =P e +P cor , formula (3);

[0051] In formula (3), P fc is the fuel cell stack power (fuel cell system output power) of the fuel cell vehicle, P cor is the fuel cell system correction power (i.e. fuel cell correction stack power), P e The power required for the entire vehicle power system of a fuel cell vehicle.

[0052] For the present invention, the basic process of the battery stack power reconstruction method based on the power following strategy is as follows: Figure 3 As shown, Figure 3 The power battery in the figure is the power battery. First, the required power condition of the vehicle power system is calculated according to the Chinese working condition, and then the current power battery SOC and the average value of the maximum and minimum power battery SOC are compared. The fuel cell system correction power is calculated using formula (2), and then substituted into formula (3) to obtain the corresponding fuel cell system output power (i.e., the fuel cell stack power) under the current vehicle speed state.

[0053] For the present invention, the fuel cell vehicle stack power reconstruction method provided by the present invention can provide a guiding basis for the energy management of fuel cell vehicles and provide a stack usage condition reference for the durability test of fuel cell vehicles.

[0054] In addition, based on the above-mentioned method for reconfiguring the power of a fuel cell vehicle stack based on Chinese operating conditions provided by the present invention, the present invention also provides a fuel cell vehicle stack power reconfiguration device based on Chinese operating conditions, such as Figure 4 As shown, it includes the following modules:

[0055] The vehicle power system required power calculation module is used to calculate the vehicle power system required power of the fuel cell vehicle based on the vehicle power balance equation, and then send it to the fuel cell system output power calculation module;

[0056] The fuel cell system correction power calculation module is used to obtain the real-time state of charge SOC (i.e., current SOC) of the power battery of the fuel cell vehicle, and pre-set the maximum value and minimum value of the state of charge SOC of the power battery, and then obtain the fuel cell system correction power based on the preset fuel cell system correction power (i.e., fuel cell stack power) calculation formula, and then send it to the fuel cell system output power calculation module;

[0057] The fuel cell system output power calculation module is respectively connected to the vehicle power system demand power calculation module and the fuel cell system correction power calculation module, and is used to sum the vehicle power system demand power sent by the vehicle power system demand power calculation module and the fuel cell system correction power sent by the fuel cell system correction power calculation module to obtain the fuel cell stack power of the fuel cell vehicle, that is, to obtain the fuel cell system output power.

[0058] In terms of specific implementation, the vehicle power system demand power calculation module is specifically used to use the existing vehicle speed-time curve of the Chinese operating conditions and calculate the vehicle power system demand power of the fuel cell vehicle based on the vehicle power balance equation.

[0059] To sum up, compared with the prior art, the present invention provides a fuel cell vehicle stack power reconstruction method and device based on Chinese operating conditions, which are scientifically designed and can reconstruct equivalent fuel cell stack power conditions according to vehicle speed conditions, thereby providing a basis for relevant tests of fuel cell vehicles.

[0060] By applying the present invention, it can be used to construct a fuel cell stack power condition that conforms to China's operating conditions, realize the reconstruction of the fuel cell vehicle stack power condition based on China's operating conditions, and then be used to provide guidance for fuel cell engine calibration tests, fuel cell vehicle energy management strategy formulation and development, fuel cell vehicle durability test evaluation, etc. It has the advantages of strong operability and clear goals, which is conducive to improving the energy utilization rate of fuel cell vehicles and promoting the development of their technology.

[0061] The present invention utilizes the existing vehicle speed-time curve of China's operating conditions, obtains the vehicle acceleration-time curve by differentiation, and then obtains the vehicle power system demand power at different speeds based on the vehicle power balance equation. Combined with a specially formulated power allocation strategy for fuel cell vehicles, the fuel cell stack power (i.e., fuel cell system output power) operating condition curve is finally reconstructed by judging parameters such as the vehicle's SOC and speed.

[0062] The present invention can realize the reconstruction of the fuel cell vehicle stack power condition based on the Chinese working condition, and solve the problem of converting the fuel cell vehicle "speed-time" working condition to the "stack power-time" working condition. The conversion method of the two working conditions is given, thereby providing guidance for the relevant research and development technology of fuel cell vehicles.

[0063] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A fuel cell vehicle stack power reconstruction method based on Chinese operating conditions, characterized in that: The fuel cell vehicle comprises two power devices, a fuel cell and a power battery. The method comprises the following steps: The first step is to calculate the required power of the fuel cell vehicle's power system based on the vehicle power balance equation; The second step is to analyze the energy management strategy of the fuel cell vehicle. When the energy management strategy of the fuel cell vehicle adopts the power following strategy, the specific analysis operation is: obtain the real-time state of charge SOC of the power battery of the fuel cell vehicle, and pre-set the maximum value and the minimum value of the state of charge SOC of the power battery, and then obtain the fuel cell system correction power based on the preset fuel cell system correction power calculation formula; The third step is to sum the vehicle power system demand power obtained in the first step and the fuel cell system correction power obtained in the second step to obtain the fuel cell stack power of the fuel cell vehicle, that is, the fuel cell system output power; In the first step, the vehicle speed-time curve of the existing Chinese working conditions is used to calculate the required power of the fuel cell vehicle's power system based on the vehicle power balance equation; After the third step, the following steps are included: Step 4: Redraw a fuel cell stack power curve of the fuel cell vehicle by taking the fuel cell stack power of the fuel cell vehicle obtained in the step 3 as the ordinate and taking the driving time of the fuel cell vehicle corresponding to the fuel cell stack power of the fuel cell vehicle as the abscissa; In the second step, the preset fuel cell system correction power P cor The calculation formula is as follows: In formula (2), c is a correction coefficient, which is greater than zero; hi_soc is a preset maximum state of charge SOC value of the power battery; lo_soc is a preset minimum state of charge SOC value of the power battery; and SOC is the real-time state of charge SOC of the power battery.

2. The fuel cell vehicle stack power reconstruction method based on Chinese operating conditions according to claim 1 is characterized in that: After the third step, the following steps are included: Subtract the real-time state of charge SOC of the power battery of the fuel cell vehicle from the average of the preset maximum state of charge SOC value and the preset minimum state of charge SOC value of the power battery. If the difference obtained is greater than zero, the first power output mode is executed; if the difference obtained is less than zero, the second power output mode is executed; The first power output mode is specifically: controlling the fuel cell to discharge and the power battery to charge, so that the fuel cell alone provides the total output power of the fuel cell vehicle; The second power output mode is specifically: controlling the fuel cell and the power battery to discharge simultaneously, so that the fuel cell and the power battery together provide the total output power of the fuel cell vehicle.

3. The fuel cell vehicle stack power reconstruction method based on Chinese operating conditions as claimed in claim 1 is characterized in that: In the first step, the vehicle power balance equation is as follows: In formula (1), P e The power required by the whole vehicle power system of the fuel cell vehicle; η T is the vehicle transmission efficiency; G is the vehicle gravity; f is the rolling resistance coefficient; i is the slope; C D is the air resistance coefficient; A is the frontal area of ​​the vehicle; σ is the rotational mass conversion coefficient; m is the vehicle mass; v is the vehicle speed, and t is the vehicle driving time.

4. A device for implementing the fuel cell vehicle stack power reconstruction method based on Chinese operating conditions as described in any one of claims 1 to 3, characterized in that: Includes the following modules: The vehicle power system required power calculation module is used to calculate the vehicle power system required power of the fuel cell vehicle based on the vehicle power balance equation, and then send it to the fuel cell system output power calculation module; The fuel cell system correction power calculation module is used to obtain the real-time state of charge SOC of the power battery of the fuel cell vehicle, and pre-set the maximum value and the minimum value of the state of charge SOC of the power battery, and then obtain the fuel cell system correction power based on the preset fuel cell system correction power calculation formula, and then send it to the fuel cell system output power calculation module; The fuel cell system output power calculation module is respectively connected to the vehicle power system demand power calculation module and the fuel cell system correction power calculation module, and is used to sum the vehicle power system demand power sent by the vehicle power system demand power calculation module and the fuel cell system correction power sent by the fuel cell system correction power calculation module to obtain the fuel cell stack power of the fuel cell vehicle, that is, to obtain the fuel cell system output power.

5. The device according to claim 4, characterized in that The vehicle power system demand power calculation module is specifically used to use the existing vehicle speed-time curve of the Chinese working conditions and based on the vehicle power balance equation to calculate the vehicle power system demand power of the fuel cell vehicle.

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