A control system and control method for a fuel cell radiator fan in a commercial vehicle.

Abstract

This invention discloses a radiator fan control system for a commercial vehicle fuel cell, comprising a cooling circuit system and a control system; the cooling circuit subsystem includes a fuel cell system, a radiator, an electric fan, and a water temperature sensor, wherein the electric fan is used to cool the radiator; the fuel cell system, the radiator, and the water temperature sensor form a large circulation loop; the fuel cell system includes a fuel cell stack, a stack inlet temperature sensor, an electric water pump, an electric thermostat, and a stack outlet temperature sensor, wherein the fuel cell stack, the stack inlet temperature sensor, the electric water pump, and the electric thermostat form a small circulation loop.

Description

Technical Field

[0001] This invention belongs to the field of radiator fan control systems, specifically relating to a radiator fan control system and control method for a commercial vehicle fuel cell. Background Technology

[0002] Chinese invention patent CN114967421A discloses a PID control method and system for a fuel cell fan, which addresses the problems of large steady-state error, poor dynamic performance, and susceptibility to local minima in the PID control method for fuel cell cooling fans. The method includes: starting the fan; determining the measured and expected values ​​of the target quantity for fuel cell operation, inputting them into an initial neural network to obtain initial values ​​for the PID control coefficients; determining the performance index of the fan executing the PID control with the above initial values, using it as the optimization target to iteratively optimize the parameters of the neural network until the performance index reaches a set accuracy, thus obtaining optimized values ​​for the PID control coefficients; executing the PID control with the above optimized values ​​on the fan, identifying whether the difference between the measured and expected values ​​of the target quantity for fuel cell operation conforms to a set range; if so, maintaining the fan speed constant; otherwise, reselecting the neural network for parameter optimization.

[0003] This invention focuses on the overall control concept and method of fuel cell fans. However, in commercial vehicle applications, due to the large overall output power of fuel cells, the heat dissipation requirements for the entire vehicle are high. Therefore, multiple electric fans are required in actual vehicle applications, and multiple radiators may be needed when a single radiator is insufficient. In this case, it is necessary to solve the control problem of multiple electric fans and multiple fans from multiple radiators in a vehicle environment. The solution to this problem is not mentioned in patent CN114967421A.

[0004] Chinese invention patent CN115472877A discloses a fuel cell cooling fan control method and system. The method includes the following steps: acquiring the fuel cell outlet coolant temperature as the input temperature; using a trained temperature control model, determining the number of cooling fans based on the ratio of the acquired outlet coolant temperature to the target temperature; obtaining the cooling fan duty cycle signal corresponding to the target temperature using the trained temperature control model based on the acquired outlet coolant temperature; and outputting the corresponding speed of the cooling fan based on the duty cycle signal. If the acquired outlet coolant temperature exceeds the target temperature range, adjusting the weights using the trained temperature control model to obtain an updated cooling fan duty cycle signal and the number of cooling fans. Based on a linear heat dissipation relationship, neural network weights are added for PWM regulation, further improving the heat dissipation effect.

[0005] This invention proposes a control method for radiators equipped with multiple fans, using the ratio of the outlet coolant temperature to the target temperature to determine the number of fans operating. However, it does not consider the cooling effect of fans at different radiator locations. In practical applications, when a radiator is equipped with multiple fans, fans positioned at different locations have different cooling efficiencies at the same speed, thus requiring further consideration of how fans in different locations should operate. Furthermore, the control effect of this patent relies on the training results of a "temperature control model," and if the outlet coolant temperature exceeds the target temperature range, the model weights need to be adjusted to redetermine the number of fans operating and their duty cycles. Additionally, a PWM adjustment via network weights is added. The algorithm is complex, and its operating efficiency is limited. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, this invention provides a control system for the radiator fans of a commercial vehicle fuel cell, including a detailed control method and a controller for its implementation. By controlling the coordinated operation of each fan in the radiator, efficient heat dissipation is achieved, quickly and accurately meeting the temperature control requirements of the fuel cell system, thus solving the aforementioned problems.

[0007] To address the aforementioned problems in the existing technology, the technical solution adopted by this invention is as follows:

[0008] A radiator fan control system for a commercial vehicle fuel cell includes a cooling circuit system and a control system;

[0009] The cooling circuit system includes a fuel cell system, a radiator, an electric fan, and a water temperature sensor. The electric fan is used to cool the radiator.

[0010] The fuel cell system, radiator, and water temperature sensor form a large circulation loop.

[0011] The fuel cell system includes a fuel cell stack, a stack inlet temperature sensor, an electric water pump, an electronic thermostat, and a stack outlet temperature sensor. The fuel cell stack, stack inlet temperature sensor, electric water pump, and electronic thermostat form a small circulation loop.

[0012] The control system includes a fuel cell system control unit, a vehicle control unit, and a cooling control unit;

[0013] The vehicle control unit is electrically connected to the vehicle's CAN bus;

[0014] The cooling control unit is electrically connected to the vehicle's CAN bus, and is also electrically connected to the electric fan and water temperature sensor.

[0015] The fuel cell system control unit is electrically connected to the vehicle control unit, and the fuel cell system control unit is electrically connected to the fuel cell system. The fuel cell system control unit is used to collect the temperature of the fuel cell system.

[0016] Furthermore, the electronic fan is provided in multiple units, and each of the multiple electronic fans is electrically connected to the cooling control unit.

[0017] The electronic fan includes a first electronic fan, a second electronic fan, and a third electronic fan, which are arranged in a triangular pattern.

[0018] The electronic fan includes a first electronic fan, a second electronic fan, a third electronic fan, and a fourth fan, which are arranged in a rectangular pattern.

[0019] A method for controlling the radiator fan of a commercial vehicle fuel cell includes the following steps:

[0020] Step 1: The vehicle control unit 2 requests the fuel cell to start and outputs a certain power;

[0021] Step 2: The fuel cell control unit receives commands from the vehicle and controls the operation of its internal sub-components;

[0022] Step 3: Report the current actual inlet temperature and required temperature of fuel cell stack 11, and request the electric fan to start;

[0023] Step 4: The cooling control unit decides to activate different fans, and the fan control is PWM4;

[0024] Step 5: Determine if there is a hydrogen leak. If there is, proceed to step 6; if not, proceed to step 7.

[0025] Step 6: Set the fan speed and duty cycle to the maximum value, and continue to check for hydrogen leakage. If there is no leakage, proceed to step 8; if there is a leakage, proceed to step 9.

[0026] Step 7: Set the fan speed and duty cycle to PWM4;

[0027] Step 8: Does the fuel cell inlet temperature meet the requirements? If it does, proceed to Step 9; if not, proceed to Step 4.

[0028] Step 9: Maintain the current fan speed duty cycle;

[0029] Step 10: Determine if the vehicle has high voltage. If yes, proceed to step 9; otherwise, end the process.

[0030] Furthermore, in step 3, the power output is based on the requirements of the vehicle control unit, and the inlet temperature, outlet temperature and required inlet temperature of the fuel cell stack are reported. The opening of the electronic thermostat is adjusted according to the system requirements, the speed of the electronic water pump is controlled, and the operation request of the electronic fan equipped with the radiator is issued.

[0031] Furthermore, step 4 includes the following steps:

[0032] Step 41: The cooling control unit collects the heat sink outlet temperature through the temperature sensor. Based on the temperature status and the heat dissipation capacity of the single fan, it initially determines the start-up temperature and speed control duty cycle PWM1 of the first electronic fan, the second electronic fan, and the third electronic fan.

[0033] Step 42: Collect the stack inlet temperature and required inlet temperature reported by the fuel cell system, and formulate the duty cycle PWM2 for fan speed control due to water temperature control deviation.

[0034] Step 43: Collect the power demand of the fuel cell and the actual net output power of the fuel cell system. Based on the changes in the power demand and the actual net output power, formulate the duty cycle PWM3 for fan speed control to predict and compensate for changes in the heat dissipation demand of the fuel cell system caused by power changes.

[0035] Step 44: The sum of PWM1+PWM2+PWM3 is used as the final electronic fan control command (not less than the minimum fan start speed duty cycle and not greater than the maximum fan speed duty cycle), which controls the three electronic fans to rotate and dissipate heat from the heat sink.

[0036] Furthermore, PWM1 is the feedforward control command for the electric fan. It is set according to the characteristics of the cooling system and can control the fluctuation of the fan speed for coarse control of the cooling system temperature.

[0037] PWM2 is the feedback control command for the electric fan, which is set according to the deviation between the actual inlet temperature and the required inlet temperature of the fuel cell stack, and is used to adjust the temperature deviation of the cooling system.

[0038] PWM3 is a predictive compensation control command for the electric fan. It is set according to the changes in the fuel cell output power required by the vehicle and the actual net output power of the fuel cell system, and is used for early prediction and compensation control of the temperature change of the cooling system.

[0039] Furthermore, three electric fans are installed in front of the radiator; in actual commercial vehicle applications, there may be 4-6 or even more electric fans. Further, in step 6, when the vehicle control unit 2 reports a hydrogen concentration leak and the vehicle is currently under high voltage, the first, second, and third electric fans are controlled to operate at maximum speed. The high-speed operation of the electric fans quickly disperses the leaking hydrogen, preventing a large accumulation and potential hydrogen leak safety issues.

[0040] Furthermore, in step 8, after the hydrogen concentration leakage fault disappears, the actual inlet temperature of the fuel cell stack is continuously monitored to see if it meets the target requirements. If it does, the current speed control commands for each electronic fan are maintained; if not, the PWM values ​​of each electronic fan are continuously adjusted.

[0041] Furthermore, in step 10, when the cooling control unit detects that the high voltage of the vehicle has been de-energized, it stops controlling each electric fan.

[0042] The beneficial effects of this invention are:

[0043] This invention details the structure of a commercial vehicle fuel cell radiator fan control system, including the connection methods of the various control units and components within the control system, the signals involved, and their detailed interaction methods. It offers significant guidance for implementation and is a feature not found in existing technologies one and two.

[0044] Based on the application requirements of commercial vehicles, this invention proposes a detailed control method for a fuel cell radiator equipped with multiple electric fans. Each electric fan can operate independently or in combination, depending on the actual heat dissipation needs. Furthermore, considering the heat dissipation efficiency of the electric fans at different locations on the radiator, a combined control method is proposed.

[0045] This invention addresses the problem of electric fan speed control by proposing a combination of feedforward control based on system characteristics, feedback control based on the difference between the required inlet temperature of the fuel cell and the actual temperature, and predictive compensation control based on changes in the output power of the fuel cell system. This approach can quickly, accurately, and efficiently meet the cooling water temperature control requirements of the fuel cell system.

[0046] This invention, based on the implementation of a control system architecture and its control method, proposes a cooling control unit, i.e., a cooling controller, to implement this control method. This facilitates fan control from the perspective of overall vehicle requirements. For example, in this invention, when a hydrogen leak is detected, the radiator fan can rotate at high speed to disperse the leaking hydrogen. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the structure of the commercial vehicle fuel cell radiator fan control system of the present invention.

[0048] Figure 2 This is a flowchart illustrating the overall implementation of the commercial vehicle fuel cell radiator fan control method of the present invention.

[0049] Figure 3 This is a schematic diagram of different combinations of fans in the commercial vehicle fuel cell radiator of the present invention.

[0050] In the diagram: 1-Cooling control unit; 2-Vehicle control unit; 3-Fuel cell system control unit; 4-Vehicle CAN bus; 5-First electric fan; 6-Second electric fan; 7-Third electric fan; 8-Radiator; 9-Water temperature sensor; 10-Stack outlet temperature sensor; 11-Fuel cell stack; 12-Stack inlet temperature sensor; 13-Electronic water pump; 14-Electronic thermostat; 15-Fuel cell system. Detailed Implementation

[0051] The present invention will be further described below with reference to the accompanying drawings and reference numerals.

[0052] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0053] The terms “first,” “second,” “third,” etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0054] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0055] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0056] Example 1:

[0057] like Figure 1 As shown, a radiator fan control system for a commercial vehicle fuel cell includes a cooling circuit system and a control system.

[0058] The cooling circuit subsystem includes a fuel cell system 15, a radiator 8, an electric fan, and a water temperature sensor 9. The electric fan is used to cool the radiator 8.

[0059] The fuel cell system 15, radiator 8 and water temperature sensor 9 form a large circulation loop;

[0060] The fuel cell system 15 includes a fuel cell stack 11, a stack inlet temperature sensor 12, an electric water pump 13, an electronic thermostat 14, and a stack outlet temperature sensor 10. The stack outlet temperature sensor 10, fuel cell stack 11, stack inlet temperature sensor 12, electric water pump 13, and electronic thermostat 14 form a small circulation loop. Cooling large and small circulation working modes: When the fuel cell starts up, the small circulation (located inside the fuel cell system 15) is used first. When the system temperature reaches a certain threshold, the large circulation is gradually opened by controlling the opening of the electronic thermostat, and the electric fan is requested to work.

[0061] The control system includes a fuel cell system control unit 3, a vehicle control unit 2, and a cooling control unit 1;

[0062] The vehicle control unit 2 is electrically connected to the vehicle CAN bus 4;

[0063] The cooling control unit 1 is electrically connected to the vehicle's CAN bus 4, and the cooling control unit 1 is electrically connected to the electric fan and the water temperature sensor 9;

[0064] The fuel cell system control unit 3 is electrically connected to the vehicle control unit 2, and the fuel cell system control unit 3 is electrically connected to the fuel cell system 15. The fuel cell system control unit 3 is used to collect the temperature of the fuel cell system 15.

[0065] Example 2:

[0066] Based on Example 1, such as Figure 3 As shown, there are multiple electronic fans, and each of the multiple electronic fans is electrically connected to the cooling control unit 1.

[0067] The electronic fan includes a first electronic fan 5, a second electronic fan 6, and a third electronic fan 7, which are arranged in a triangular pattern.

[0068] The electronic fan includes a first electronic fan 5, a second electronic fan 6, a third electronic fan 7, and a fourth fan, which are arranged in a rectangular pattern.

[0069] The inlet pipe of the radiator 8 is connected to the cooling water outlet of the fuel cell system 15, and the outlet of the radiator 8 is connected to the cooling water inlet of the fuel cell system 15.

[0070] The electronic thermostat 14 and electronic water pump 13 of the fuel cell system 15 are both electrically connected to the fuel cell system control unit 3.

[0071] The water temperature sensor 9 is located at the outlet of the radiator 8 and simultaneously receives the actual inlet temperature of the fuel cell stack reported by the fuel cell system. The two temperatures can be redundantly controlled, making the control system more reliable.

[0072] Example 3:

[0073] like Figure 2 As shown, a method for controlling the radiator fan of a commercial vehicle fuel cell includes the following steps:

[0074] Step 1: The vehicle control unit 2 requests the fuel cell to start and outputs a certain power;

[0075] Step 2: The fuel cell control unit receives commands from the vehicle and controls the operation of its internal sub-components;

[0076] Step 3: Report the current actual inlet temperature and required temperature of fuel cell stack 11, and request the electric fan to start;

[0077] Step 4: Cooling control unit 1 decides to start different fans, and the fan control is PWM4;

[0078] Step 5: Determine if there is a hydrogen leak. If there is, proceed to step 6; if not, proceed to step 7.

[0079] Step 6: Set the fan speed and duty cycle to the maximum value, and continue to check for hydrogen leakage. If there is no leakage, proceed to step 8; if there is a leakage, proceed to step 9.

[0080] Step 7: Set the fan speed and duty cycle to PWM4;

[0081] Step 8: Does the fuel cell inlet temperature meet the requirements? If it does, proceed to Step 9; if not, proceed to Step 4.

[0082] Step 9: Maintain the current fan speed duty cycle;

[0083] Step 10: Determine if the vehicle has high voltage. If yes, proceed to step 9; otherwise, end the process.

[0084] Example 4:

[0085] Based on Example 3, in step 1, the vehicle control unit 2 issues a fuel cell system start command and a power demand allocated to the fuel cell according to the vehicle's requirements.

[0086] In step 2, after receiving the working instruction, the fuel cell system control unit 3 controls each unit of its system to start working.

[0087] In step 3, the power output is based on the requirements of the vehicle control unit 2, and the inlet temperature, outlet temperature and required inlet temperature of the fuel cell stack 11 are reported. The opening of the electronic thermostat 14 is adjusted according to the system requirements, the speed of the electronic water pump 13 is controlled, and the working request of the electronic fan equipped with the radiator 8 is issued.

[0088] Example 5:

[0089] Based on Example 3, such as Figure 3 As shown, step 4 includes the following steps:

[0090] Step 41: The cooling control unit 1 collects the outlet temperature of the heat sink 8 through the temperature sensor. Based on the temperature status and the heat dissipation capacity of the single fan, it initially sets the start-up temperature and speed control duty cycle PWM1 of the first electronic fan 5, the second electronic fan 6, and the third electronic fan 7.

[0091] Step 42: Collect the stack inlet temperature and required inlet temperature reported by the fuel cell system 15, and formulate the duty cycle PWM2 for fan speed control due to water temperature control deviation.

[0092] Step 43: Collect the power demand of the fuel cell and the actual net output power of the fuel cell system 15. Based on the changes in the power demand and the actual net output power, formulate the duty cycle PWM3 for fan speed control to predict and compensate for changes in the heat dissipation demand of the fuel cell system 15 caused by power changes.

[0093] Step 44: The sum of PWM1+PWM2+PWM3 is used as the final electronic fan control command (not less than the minimum fan start speed duty cycle and not greater than the maximum fan speed duty cycle), which controls the three electronic fans to rotate and dissipate heat from the heat sink 8.

[0094] PWM1 is the feedforward control command for the electric fan. It is set according to the characteristics of the cooling system and can control the fluctuation of the fan speed, which is used for coarse control of the cooling system temperature.

[0095] PWM2 is the feedback control command for the electric fan, which is set according to the deviation between the actual inlet temperature and the required inlet temperature of the fuel cell stack, and is used to adjust the temperature deviation of the cooling system.

[0096] PWM3 is a predictive compensation control command for the electric fan. It is set according to the changes in the fuel cell output power required by the vehicle and the actual net power output of the fuel cell system 15, and is used for early prediction and compensation control of the temperature change of the cooling system.

[0097] The combination of these three elements enables rapid and accurate adjustment of the fuel cell's cooling temperature requirements.

[0098] Example 6:

[0099] Based on Example 3, such as Figure 3 As shown, in step 4: during the fan control process of the radiator 8, the first electronic fan 5, the second electronic fan 6, and the third electronic fan 7 can each individually receive the speed control command from the cooling control unit 1. The starting operating temperature threshold for the first electronic fan 5 is set to T℃, and the stopping operating temperature threshold is set to T-2℃; the starting operating temperature threshold for the second electronic fan 6 is set to T+dt1℃, and the stopping operating temperature threshold is set to T+dt1-2℃; the starting operating temperature threshold for the third electronic fan 7 is set to T+dt2℃, and the stopping operating temperature threshold is set to T+dt2-2℃. When dt1=dt2=0, all three electronic fans can start operating simultaneously. When dt1=dt2≠0, the second electronic fan 6 and the third electronic fan 7 start operating simultaneously, with the starting operating temperature higher than that of the first electronic fan 5. When dt1≠dt2≠0, the first electronic fan 5 starts first, followed by the second electronic fan 6, and the third electronic fan 7 starts last. When dt1≠0 and dt2=0, the first electronic fan 5 and the third electronic fan 7 start operating simultaneously first, and the second electronic fan 6 starts last. When the outlet temperature of the radiator 8 reaches T℃ and a fan operation command is received, the first electronic fan 5 starts working; when the outlet temperature of the radiator 8 reaches T+dt1℃ and a fan operation command is received, the second electronic fan 6 starts working; when the outlet temperature of the radiator 8 reaches T+dt2℃ and a fan operation command is received, the third electronic fan 7 starts working.

[0100] Three electric fans are installed in front of the radiator 8, but in actual commercial vehicle applications, there may be 4-6 or even more. The electric fans positioned at different locations in front of the radiator 8 will have different cooling effects on the radiator 8 at the same speed; therefore, the order in which the electric fans in different positions start up needs to be considered. For example... Figure 3When the radiator 8 is equipped with three electric fans, a control method can be considered where the first electric fan 5 and the third electric fan 7 operate first, followed by the second electric fan 6. When the radiator 8 is equipped with four electric fans, a control method can be considered where the first electric fan 5 and the third electric fan 7 operate first, followed by the second electric fan 6 and the fourth electric fan. When the radiator 8 is equipped with five or more electric fans, priority should be given to the electric fans located diagonally on the radiator 8, with the fans in other positions operating later. The specific number of fans to be activated can be calculated by estimating the heat dissipation requirements of the fuel cell system 15 based on the required fuel cell output power of the entire vehicle and the actual net output power of the fuel cell system 15, combined with the heat dissipation capacity of a single electric fan.

[0101] Example 7:

[0102] Based on Example 3, in step 6, when the vehicle control unit 2 reports a hydrogen concentration leak and the vehicle is currently under high voltage, the first electronic fan 5, the second electronic fan 6, and the third electronic fan 7 are controlled to operate at maximum speed. The high-speed operation of the electronic fans quickly disperses the leaking hydrogen, preventing a large accumulation of leaked hydrogen and potential safety issues.

[0103] Example 8:

[0104] Based on Example 3, in step 8, after the hydrogen concentration leakage fault disappears, the actual inlet temperature of the fuel cell stack is continuously monitored to see if it meets the target requirements; if it does, the current speed control commands of each electronic fan are maintained; if not, the PWM values ​​of each electronic fan are continuously adjusted.

[0105] Example 9:

[0106] Based on Example 3, in step 10, when the cooling control unit 1 detects that the high voltage of the whole vehicle has been de-energized, it stops controlling each electric fan.

[0107] This invention is not limited to the above-described optional embodiments. Anyone can derive other various forms of products under the guidance of this invention. However, regardless of any changes made in their shape or structure, any technical solution that falls within the scope of the claims of this invention shall be protected by this invention.

Claims

1. A fan control system for a fuel cell radiator in a commercial vehicle, characterized in that: This includes the cooling circuit system and the control system; The cooling circuit system includes a fuel cell system (15), a radiator (8), an electric fan, and a water temperature sensor (9), wherein the electric fan is used to cool the radiator (8); The fuel cell system (15), radiator (8) and water temperature sensor (9) form a large circulation loop; The fuel cell system (15) includes a fuel cell stack (11), a stack inlet temperature sensor (12), an electric water pump (13), an electronic thermostat (14), and a stack outlet temperature sensor (10). The stack outlet temperature sensor (10), fuel cell stack (11), stack inlet temperature sensor (12), electric water pump (13), and electronic thermostat (14) form a small circulation loop. The control system includes a fuel cell system control unit (3), a vehicle control unit (2), and a cooling control unit (1). The vehicle control unit (2) is electrically connected to the vehicle CAN bus (4); The cooling control unit (1) is electrically connected to the vehicle CAN bus (4), and the cooling control unit (1) is electrically connected to the electric fan and the water temperature sensor (9); The fuel cell system control unit (3) is electrically connected to the vehicle control unit (2), and the fuel cell system control unit (3) is electrically connected to the fuel cell system (15). The fuel cell system control unit (3) is used to collect the temperature of the fuel cell system (15). The cooling control unit (1) collects the outlet temperature of the radiator (8), and based on this temperature state and the heat dissipation capacity of the single fan, initially sets the start-up temperature and speed control duty cycle PWM1 for the first electronic fan (5), the second electronic fan (6), and the third electronic fan (7); by collecting the stack inlet temperature and its required inlet temperature reported by the fuel cell system (15), it sets the duty cycle PWM2 for fan speed control due to water temperature control deviation; by collecting the fuel cell demand power and the actual net output power of the fuel cell system (15), it sets the fan speed control duty cycle PWM3 for predicting and compensating for changes in the heat dissipation demand of the fuel cell system (15) caused by power changes; the sum of PWM1, PWM2, and PWM3 is the final electronic fan control command, which controls the rotation of the three electronic fans to dissipate heat from the radiator (8).

2. The commercial vehicle fuel cell radiator fan control system according to claim 1, characterized in that: The electronic fan is provided in multiple units, and each electronic fan is electrically connected to the cooling control unit (1).

3. The commercial vehicle fuel cell radiator fan control system according to claim 2, characterized in that: The electronic fan includes a first electronic fan (5), a second electronic fan (6), and a third electronic fan (7), which are arranged in a triangular pattern.

4. The commercial vehicle fuel cell radiator fan control system according to claim 2, characterized in that: The electronic fan includes a first electronic fan (5), a second electronic fan (6), a third electronic fan (7), and a fourth fan, which are arranged in a rectangular shape.

5. The commercial vehicle fuel cell radiator fan control system according to claim 1, characterized in that: The inlet pipe of the radiator (8) is connected to the cooling water outlet of the fuel cell system (15), and the outlet of the radiator (8) is connected to the cooling water inlet of the fuel cell system (15).

6. The commercial vehicle fuel cell radiator fan control system according to claim 1, characterized in that: The electronic thermostat (14) and electronic water pump (13) of the fuel cell system (15) are electrically connected to the fuel cell system control unit (3).

7. A method for controlling the radiator fan of a commercial vehicle fuel cell based on the system according to any one of claims 1-6, comprising the following steps: Step 1: The vehicle control unit (2) requests the fuel cell to start and outputs a certain power; Step 2: The fuel cell control unit receives commands from the vehicle and controls the operation of its internal sub-components; Step 3: Report the current inlet temperature and required temperature of the actual fuel cell stack (11), and request the electric fan to start; Step 4: The cooling control unit (1) decides to start different fans, and the fan control is PWM4; Step 5: Determine if there is a hydrogen leak. If there is, proceed to step 6; if not, proceed to step 7. Step 6: Set the fan speed and duty cycle to the maximum value, and continue to check for hydrogen leakage. If there is no leakage, proceed to step 8; if there is a leakage, proceed to step 9. Step 7: Set the fan speed and duty cycle to PWM4; Step 8: Does the fuel cell inlet temperature meet the requirements? If it does, proceed to Step 9; if not, proceed to Step 4. Step 9: Maintain the current fan speed duty cycle; Step 10: Determine if the vehicle has high voltage. If yes, proceed to step 9; otherwise, end the process.

8. The method for controlling the radiator fan of a commercial vehicle fuel cell according to claim 7, characterized in that: In step 4: the starting operating temperature threshold of the first electronic fan (5) is set to T℃, and the stopping operating temperature threshold is set to T-2℃; The starting operating temperature threshold of the second electronic fan (6) is set to T+dt1℃, and the stopping operating temperature threshold is set to T+dt1-2℃; The starting operating temperature threshold of the third electronic fan (7) is set to T+dt2℃, and the stopping operating temperature threshold is set to T+dt2-2℃; When dt1=dt2=0, all three electronic fans can start working simultaneously. When dt1=dt2≠0, the second electronic fan (6) and the third electronic fan (7) start working simultaneously, and the starting temperature is greater than that of the first electronic fan (5). When dt1≠dt2≠0, the first electronic fan (5) starts first, followed by the second electronic fan (6), and the third electronic fan (7) starts last. When dt1≠0 and dt2=0, the first electronic fan (5) and the third electronic fan (7) start working simultaneously, and the second electronic fan (6) starts working last. When the outlet temperature of the radiator (8) reaches T℃ and the fan is activated by the fan operation command, the first electronic fan (5) starts to work. When the outlet temperature of the radiator (8) reaches T+dt1℃ and the fan is activated by the fan operation command, the second electronic fan (6) starts to work. When the outlet temperature of the radiator (8) reaches T+dt2℃ and the fan is activated by the fan operation command, the third electronic fan (7) starts to work.

9. The commercial vehicle fuel cell radiator fan control method according to claim 7, characterized in that: In step 6, when the vehicle control unit (2) reports a hydrogen concentration leak and the vehicle is currently in a high-voltage state, the first electronic fan (5), the second electronic fan (6), and the third electronic fan (7) are controlled to operate at maximum speed.

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