Fuel cell electric tractor and energy management method

Abstract

The application discloses a fuel cell electric tractor and an energy management method, and can dynamically adjust energy output through an accurate energy management system, optimize according to factors such as working conditions and loads, and maximize energy utilization efficiency. Compared with a traditional internal combustion engine tractor, the fuel cell electric tractor can realize more efficient energy utilization, thereby reducing energy consumption and cost. Compared with the traditional internal combustion engine tractor, the fuel cell electric tractor can effectively reduce tail gas emission and reduce pollution to the environment. Through energy management of the fuel cell system, the application can realize optimal energy utilization of the whole machine under different working conditions, improve the running efficiency of the vehicle, prolong the cruising range, thereby reducing energy consumption and improving the economy of the tractor. Effective implementation of the application helps to promote the development and application of clean energy technology, provides important support for realizing sustainable development and responding to climate change, and has positive social and environmental significance.

Description

Technical Field

[0001] This invention relates to the field of electric tractors, and more specifically to a fuel cell electric tractor and an energy management method thereof. Background Technology

[0002] With the rapid development of the global economy and population growth, the depletion of energy resources has become a serious challenge facing the world. The use of fossil fuels has led to a large amount of greenhouse gas emissions, exacerbating global climate change and environmental pollution problems, and causing serious impacts on the ecological environment and human health.

[0003] Fuel cell tractors use hydrogen fuel cells as their power source. Hydrogen can be produced through water electrolysis, biomass gasification, and other methods, making it a clean and renewable energy source. This effectively reduces dependence on fossil fuels, lowers greenhouse gas emissions, and helps address climate change and environmental pollution. Fuel cell systems have high energy conversion efficiency, directly converting hydrogen and oxygen into electricity, making them more efficient than traditional internal combustion engine systems and contributing to improved energy utilization. The use of fuel cell tractors can reduce noise and exhaust emissions, improve the quality of farmland environments, promote sustainable agricultural development, reduce dependence on fossil fuels, minimize environmental impact, and provide cleaner and more efficient power support for agricultural production.

[0004] In summary, how to provide a fuel cell electric tractor and its energy management method has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention provides a fuel cell electric tractor and an energy management method. The present invention can solve the problems of short driving time, high energy consumption and unreasonable power distribution of existing fuel cell systems.

[0006] To achieve the aforementioned inventive objectives, the present invention employs the following technical solution:

[0007] A fuel cell electric tractor includes a differential mechanism, a left half-shaft, a transmission system, a drive motor, a first DC / AC, an energy management controller, a supercapacitor, a proton exchange membrane fuel cell, a power battery, a second DC / AC, a PTO motor, a PTO high / low gear pair, a PTO, and a right half-shaft. The PTO is connected to the PTO high / low gear pair, which is connected to the PTO motor. The PTO motor is connected to the second DC / AC, which is connected to the energy management controller via a signal. The energy management controller is connected to the first DC / AC, the proton exchange membrane fuel cell, the supercapacitor, and the power battery via signals. The energy management controller, supercapacitor, proton exchange membrane fuel cell, and power battery together form a fuel cell system. The first DC / AC is connected to the drive motor, which is connected to the transmission system. The transmission system is connected to the differential mechanism, which is connected to the left and right half-shafts. The left and right half-shafts are connected to the left and right drive wheels, respectively. The proton exchange membrane fuel cell is connected to the supercapacitor and the power battery.

[0008] The fuel cell electric tractor, wherein the proton exchange membrane fuel cell includes a hydrogen storage device, a hydrogen inlet, an oxygen inlet, an oxygen supply system, a hydrogen exhaust port, an oxygen exhaust port, a hydrogen treatment system, an oxygen treatment system, an anode, a proton exchange membrane, and a cathode. An anode and a cathode are respectively located on the left and right sides of the proton exchange membrane. The proton exchange membrane, anode, and cathode form a fuel cell stack. The hydrogen inlet on the anode is connected to the hydrogen storage device, the hydrogen exhaust port on the anode is connected to the hydrogen treatment system, the oxygen inlet on the cathode is connected to the oxygen supply system, and the oxygen exhaust port on the cathode is connected to the oxygen treatment system.

[0009] The fuel cell electric tractor mentioned above uses a hydrogen storage device, which is a hydrogen cylinder.

[0010] The fuel cell electric tractor, wherein the PTO is connected to the corresponding input shaft of the agricultural machinery equipment.

[0011] The fuel cell electric tractor described above uses a lithium iron phosphate battery as its power battery to buffer fluctuations in load power.

[0012] In the aforementioned fuel cell electric tractor, the supercapacitor is used to compensate for the instantaneous response power of the motor.

[0013] An energy management method for a fuel cell electric tractor, comprising the following steps: First, determining the stages and states of the problem, dividing the problem into multiple stages, and defining the state of each stage; determining decision variables and state transition equations, i.e., how decisions at each stage transition to the state of the next stage; establishing an optimization model, defining the objective function and constraints to describe the optimization objective of the problem; using recursive or iterative methods to calculate the optimal state and decision at each stage to determine the optimal solution to the entire problem; and implementing an optimized control strategy for energy management based on the optimal state and decision to achieve optimal energy utilization and system performance. The specific method is as follows:

[0014] The multi-stage decision-making process divides a specific tractor plowing cycle into N equal stages to find the optimal power allocation ratio of the energy system. The battery system mathematical model employs a dual-polarization reaction equivalent circuit model and a Rint equivalent circuit model to reflect the battery's polarization characteristics. In the energy management strategy, the SOC of the power battery and the SOC of the supercapacitor are used as state variables, their constraint range determined by a common operating range. The fuel cell output power is used as the decision variable, and its constraint range is determined by analyzing the tractor's operating power demand and performance indicators. Simultaneously, the state variables and decision variables are discretized.

[0015] x(t+1)=f(x(t),u(t)) (1)

[0016] In the formula, x(t) is the value of the state variable at time t; x(t+1) is the value of the state variable at time t+1; u(t) is the decision variable; and f() is the functional relationship between the state variable and the decision variable.

[0017] Therefore, the state transition equation can be expressed as:

[0018]

[0019] In the formula, Q * () represents the optimal cost function from the current stage to N; C t () represents the stage cost function; min{} represents the minimum value of the function;

[0020] Considering that both high-power and low-power operation of fuel cells have a significant impact on their lifespan, the output mode is divided into three modes: high power demand, normal power demand, and stable output. During the decision-making process, the operating mode of the fuel cell is determined based on the power demand, and the corresponding range of decision variables under different modes is traversed to find the optimal decision.

[0021] To optimize the power distribution ratio among the three energy sources, the equivalent hydrogen consumption of the energy system is used as the cost function of the DP algorithm, expressed as:

[0022] Q = Cfc (t)+C bat (t)+C sup (t) (3)

[0023] In the formula, Q is the cost function;

[0024] C fc (t) represents the hydrogen consumption of the fuel cell, in g;

[0025] C bat (t) represents the equivalent hydrogen consumption of the power battery, in g;

[0026] C sup (t) represents the equivalent hydrogen consumption of the supercapacitor, in g;

[0027] The equivalent hydrogen consumption of the energy system is expressed as follows:

[0028]

[0029]

[0030]

[0031] In the formula, P fc P bat P sc These are the output power (kW) of the PEMFC, the power battery, and the supercapacitor, respectively.

[0032] η fc and These are the instantaneous efficiency and average efficiency of the fuel cell, respectively.

[0033] η chg_bat and η dis_bat These refer to the charging and discharging efficiency of the power battery, respectively.

[0034] η chg_sc and η dis_sc These refer to the charging and discharging efficiencies of the supercapacitor, respectively.

[0035] It has the low calorific value of hydrogen.

[0036] The integral symbol is used.

[0037] Furthermore, the state and decision variables of the energy system should be confined within certain boundary conditions, and should also satisfy the optimization constraints of the driving system. These boundary conditions collectively determine the feasible region of the system's state and decision variables.

[0038]

[0039] In the formula, Pfc_peak This represents the peak power of the fuel cell.

[0040] P fc (t), P bat (t) and P sup (t) represents the output power of the PEMFC, power battery, and supercapacitor at time t;

[0041] SOC bat (t) and SOC sup (t) represents the state of charge of the power battery and the supercapacitor at time t;

[0042] P bat_min and P bat_max These are the minimum and maximum output power values ​​of the power battery;

[0043] P sup_min and P sup_max These are the minimum and maximum output power values ​​of the supercapacitor;

[0044] SOC bat_min and SOC bat_max These are the lower and upper limits of the state-of-charge value for the power battery;

[0045] SOC sup_min and SOC sup_max These are the lower and upper limits of the supercapacitor's charged state.

[0046] By applying the principle of optimality in dynamic programming, the optimal control at each moment is obtained by iterating backward from the final stage, thus yielding the optimal power distribution control strategy for the entire process.

[0047] The energy management method for the fuel cell electric tractor, wherein the output mode is high power demand, and the power demand range is P. demd >85% P fc_peak The decision variable range is 45% P. fc_peak ≤u≤85%P fc_peak When the output mode is normal power demand, the power demand range is 15%P. fc_rated <P demd <85% P fc_rated The decision variable range is 15% P. fc_rated ≤u≤85%P fc When the output mode is stable output, the required power range is P. demd <15% P fc_rated The decision variable range is u = 15%P fc_rated In the above formula, P fc_peak and P fc_rated These represent the peak power and rated power of the fuel cell, respectively.

[0048] By employing the technical solution described above, the present invention has the following advantages:

[0049] This invention, through a precise energy management system, can dynamically adjust energy output and optimize it based on factors such as operating conditions and load, maximizing energy utilization efficiency. Compared to traditional internal combustion engine tractors, fuel cell electric tractors achieve more efficient energy utilization, thereby reducing energy consumption and costs. Furthermore, due to the zero-emission characteristic of fuel cell electric tractors, compared to traditional internal combustion engine tractors, it can effectively reduce exhaust emissions, reduce environmental pollution, and has a significant positive impact on improving air quality and reducing greenhouse gas emissions. Through energy management of the fuel cell system, this invention enables the entire machine to achieve optimal energy utilization under different operating conditions, improving vehicle operating efficiency, extending driving range, thereby reducing energy consumption and improving the tractor's economy. The effective implementation of this invention helps promote the development and application of clean energy technologies, providing important support for achieving sustainable development and addressing climate change, and has positive social and environmental significance. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the transmission of a fuel cell electric tractor in an embodiment of the present invention;

[0051] Figure 2 This is a schematic diagram of the composition and structure of a proton exchange membrane fuel cell in an embodiment of the present invention;

[0052] Figure 3 This is a schematic diagram of the fuel cell system components and functions in an embodiment of the present invention;

[0053] Figure 4 This is a flowchart of the dynamic programming algorithm in an embodiment of the present invention;

[0054] Figure 5 This is a flowchart of the power distribution control of the fuel cell system in an embodiment of the present invention;

[0055] Figure 6 This is a schematic diagram of the energy management controller in an embodiment of the present invention;

[0056] Figure 7 This is a power distribution flowchart for a fuel cell electric tractor in an embodiment of the present invention;

[0057] In the diagram: 1. Differential mechanism; 2. Left half-shaft; 3. Left drive wheel; 4. Transmission system; 5. Drive motor; 6. First DC / AC; 7. Energy management controller; 8. Supercapacitor; 9. Proton exchange membrane fuel cell; 901. Hydrogen storage device; 902. Hydrogen inlet; 903. Oxygen inlet; 904. Oxygen supply system; 905. Hydrogen exhaust port; 906. Oxygen exhaust port; 907. Hydrogen processing system; 908. Oxygen processing system; 909. Anode; 910. Proton exchange membrane; 911. Cathode; 10. Power battery; 11. Second DC / AC; 12. PTO motor; 13. PTO high / low gear pair; 14. PTO; 15. Right drive wheel; 16. Right half-shaft. Detailed Implementation

[0058] The present invention can be explained in more detail through the following embodiments, but the present invention is not limited to the following embodiments;

[0059] Combined with appendix Figures 1-7 The present invention discloses a fuel cell electric tractor, comprising a differential mechanism 1, a left half-shaft 2, a transmission system 4, a drive motor 5, a first DC / AC converter 6, an energy management controller 7, a supercapacitor 8, a proton exchange membrane fuel cell 9, a power battery 10, a second DC / AC converter 11, a PTO motor 12, a PTO high / low gear pair 13, a PTO 14, and a right half-shaft 16. The PTO 14 is connected to the PTO high / low gear pair 13, the PTO high / low gear pair 13 is connected to the PTO motor 12, the PTO motor 12 is connected to the second DC / AC converter 11, and the second DC / AC converter 11 is connected to the energy management controller 7 via a signal. The energy management controller 7 is connected to the first DC / AC 6, the proton exchange membrane fuel cell 9, the supercapacitor 8, and the power battery 10 via signals. The energy management controller 7, the supercapacitor 8, the proton exchange membrane fuel cell 9, and the power battery 10 together form a fuel cell system. The first DC / AC 6 is connected to the drive motor 5, the drive motor 5 is connected to the transmission system 4, the transmission system 4 is connected to the differential mechanism 1, the differential mechanism 1 is connected to the left half-shaft 2 and the right half-shaft 16, the left half-shaft 2 and the right half-shaft 16 are connected to the left drive wheel 3 and the right drive wheel 15, respectively. The proton exchange membrane fuel cell 9 is connected to the supercapacitor 8 and the power battery 10.

[0060] Furthermore, such as Figure 2As shown, the proton exchange membrane fuel cell 9 includes a hydrogen storage device 901, a hydrogen inlet 902, an oxygen inlet 903, an oxygen supply system 904, a hydrogen exhaust port 905, an oxygen exhaust port 906, a hydrogen processing system 907, an oxygen processing system 908, an anode 909, a proton exchange membrane 910, and a cathode 911. An anode 909 and a cathode 911 are respectively located on the left and right sides of the proton exchange membrane 910. The proton exchange membrane 910, anode 909, and cathode 911 form a fuel cell stack. The hydrogen inlet 902 on the anode 909 is connected to the hydrogen storage device 901, and the hydrogen exhaust port 905 on the anode 909 is connected to the hydrogen processing system 907. The oxygen inlet 903 on the cathode 911 is connected to the oxygen supply system 904, and the oxygen exhaust port 906 on the cathode 911 is connected to the oxygen processing system 908.

[0061] Furthermore, the hydrogen storage device 901 is a hydrogen cylinder.

[0062] Furthermore, the PTO14 is connected to the corresponding input shaft of the agricultural machinery equipment.

[0063] Furthermore, the power battery 10 is a lithium iron phosphate battery, used to buffer fluctuations in load power.

[0064] Furthermore, the supercapacitor 8 is used to compensate for the instantaneous response power of the motor.

[0065] An energy management method for a fuel cell electric tractor, comprising the following steps: First, determining the stages and states of the problem, dividing the problem into multiple stages, and defining the state of each stage; determining decision variables and state transition equations, i.e., how decisions at each stage transition to the state of the next stage; establishing an optimization model, defining the objective function and constraints to describe the optimization objective of the problem; using recursive or iterative methods to calculate the optimal state and decision at each stage to determine the optimal solution to the entire problem; and implementing an optimized control strategy for energy management based on the optimal state and decision to achieve optimal energy utilization and system performance. The specific method is as follows:

[0066] The multi-stage decision-making process divides a specific tractor plowing cycle into N equal stages to find the optimal power allocation ratio of the energy system. The battery system mathematical model employs a dual-polarization reaction equivalent circuit model and a Rint equivalent circuit model to reflect the battery's polarization characteristics. In the energy management strategy, the SOC of the power battery and the SOC of the supercapacitor are used as state variables, their constraint range determined by a common operating range. The fuel cell output power is used as the decision variable, and its constraint range is determined by analyzing the tractor's operating power demand and performance indicators. Simultaneously, the state variables and decision variables are discretized.

[0067] x(t+1)=f(x(t),u(t)) (8)

[0068] In the formula, x(t) is the value of the state variable at time t; x(t+1) is the value of the state variable at time t+1; u(t) is the decision variable; and f() is the functional relationship between the state variable and the decision variable.

[0069] Therefore, the state transition equation can be expressed as:

[0070]

[0071] In the formula, Q * () represents the optimal cost function from the current stage to N; C t () represents the stage cost function; min{} represents the minimum value of the function;

[0072] Considering that both high-power and low-power operation of fuel cells have a significant impact on their lifespan, the output mode is divided into three modes: high power demand, normal power demand, and stable output. During the decision-making process, the operating mode of the fuel cell is determined based on the power demand, and the corresponding range of decision variables under different modes is traversed to find the optimal decision.

[0073] To optimize the power distribution ratio among the three energy sources, the equivalent hydrogen consumption of the energy system is used as the cost function of the DP algorithm, expressed as:

[0074] Q = C fc (t)+C bat (t)+C sup (t) (10)

[0075] In the formula, Q is the cost function;

[0076] C fc (t) represents the hydrogen consumption of the fuel cell, in g;

[0077] C bat (t) represents the equivalent hydrogen consumption of the power battery, in g;

[0078] C sup (t) represents the equivalent hydrogen consumption of the supercapacitor, in g;

[0079] The equivalent hydrogen consumption of the energy system is expressed as follows:

[0080]

[0081]

[0082]

[0083] In the formula, P fc P batP sc These are the output power (kW) of the PEMFC, the power battery, and the supercapacitor, respectively.

[0084] η fc and These are the instantaneous efficiency and average efficiency of the fuel cell, respectively.

[0085] η chg_bat and η dis_bat These refer to the charging and discharging efficiency of the power battery, respectively.

[0086] η chg_sc and η dis_sc These refer to the charging and discharging efficiencies of the supercapacitor, respectively.

[0087] It has the low calorific value of hydrogen.

[0088] The integral symbol is used.

[0089] Furthermore, the state and decision variables of the energy system should be confined within certain boundary conditions, and should also satisfy the optimization constraints of the driving system. These boundary conditions collectively determine the feasible region of the system's state and decision variables.

[0090]

[0091] In the formula, P fc_peak This represents the peak power of the fuel cell.

[0092] P fc (t), P bat (t) and P sup (t) represents the output power of the PEMFC, power battery, and supercapacitor at time t;

[0093] SOC bat (t) and SOC sup (t) represents the state of charge of the power battery and the supercapacitor at time t;

[0094] P bat_min and P bat_max These are the minimum and maximum output power values ​​of the power battery;

[0095] P sup_min and P sup_max These are the minimum and maximum output power values ​​of the supercapacitor;

[0096] SOC bat_min and SOC bat_max These are the lower and upper limits of the state-of-charge value for the power battery;

[0097] SOC sup_min and SOCsup_max These are the lower and upper limits of the supercapacitor's charged state.

[0098] By applying the principle of optimality in dynamic programming, the optimal control at each moment is obtained by iterating backward from the final stage, thus yielding the optimal power distribution control strategy for the entire process.

[0099] In implementation, when the output mode is high power demand, the power demand range is P. demd >85% P fc_peak The decision variable range is 45% P. fc_peat ≤u≤85%P fc_peak When the output mode is normal power demand, the power demand range is 15%P. fc_rated <P demd <85% P fc_rated The decision variable range is 15% P. fc_rated ≤u≤85%P fc When the output mode is stable output, the required power range is P. demd <15% P fc_rated The decision variable range is u = 15%P fc_rated In the above formula, P fc_pmk and P fc_rated These represent the peak power and rated power of the fuel cell, respectively.

[0100] In practice, the tractor PT014 can be directly connected to the corresponding input shaft of the agricultural machinery, and the power is transmitted through the high and low gear pairs 13 via mechanical connection and the PTO motor 12.

[0101] Furthermore, the proton exchange membrane fuel cell 9 serves as the main energy supply, the power battery 10 uses lithium iron phosphate batteries to buffer load power fluctuations, and the supercapacitor 8 is used to compensate for the instantaneous response power of the motor.

[0102] Furthermore, the energy management controller 7 adjusts the power output ratio between energy sources based on the pressure signal, state of charge signal, and motor characteristic signal of the hydrogen storage device 901, thereby improving the energy utilization rate of the fuel cell system and enhancing the economic efficiency of tractor operation. The energy management controller 7 is used to monitor and control the operating status of the hydrogen fuel cell system.

[0103] Furthermore, the hydrogen storage device 901 is used to store hydrogen, typically using a high-pressure hydrogen storage tank or a hydrogen compound storage system. The oxygen supply system 904 is used to provide oxygen, typically obtained from the air, but can also be supplied through an oxygen storage tank. The fuel cell stack is the core component of the hydrogen fuel cell system, including an anode 909, a cathode 911, and a proton exchange membrane 910, which generates electrical energy through the electrochemical reaction of hydrogen and oxygen.

[0104] further, Figure 3 A schematic diagram of the fuel cell system components and functions is shown.

[0105] Specifically, the energy management controller 7 adjusts the power output ratio between energy sources based on the pressure signal, state of charge signal, and motor characteristic signal of the hydrogen storage device 901, in order to improve the energy utilization rate of the fuel cell system and enhance the economic efficiency of tractor operation.

[0106] Specifically, the energy management controller 7 includes sensors, controllers, and electronic devices for monitoring and controlling the operating status of the hydrogen fuel cell system.

[0107] Specifically, the hydrogen storage device 901 is used to store hydrogen, and typically employs a high-pressure hydrogen storage tank or a hydrogen compound storage system.

[0108] Specifically, the oxygen supply system 904 is used to provide oxygen, which is usually obtained from the air or can be supplied through an oxygen storage tank.

[0109] Specifically, the fuel cell stack is the core component of the hydrogen fuel cell system, including an anode 909, a cathode 911, and a proton exchange membrane 910, which generates electrical energy through the electrochemical reaction of hydrogen and oxygen.

[0110] Specifically, the hydrogen processing system 907 is used to process hydrogen, including functions such as hydrogen purification and hydrogen flow regulation.

[0111] Specifically, the oxygen processing system 908 is used to process oxygen, including functions such as a filter and regulating oxygen flow.

[0112] Specifically, the fuel cell system is equipped with a heat dissipation system to control the temperature of the fuel cell and prevent overheating or overcooling from affecting the system.

[0113] Specifically, the fuel cell system is equipped with an auxiliary power system, including a battery pack or supercapacitor, to control the temperature of the fuel cell and prevent overheating or overcooling from affecting the system.

[0114] further, Figure 4 The flowchart of the dynamic programming algorithm is shown.

[0115] Specifically, the energy management strategy employs a dynamic programming algorithm, and the process includes: determining the stages and states of the problem, dividing the problem into multiple stages, and defining the state of each stage; determining the decision variables and state transition equations, i.e., how decisions at each stage transition to the state of the next stage; establishing an optimization model, defining the objective function and constraints to describe the optimization objective of the problem; using recursive or iterative methods to calculate the optimal state and decision at each stage to determine the optimal solution to the entire problem; and implementing an optimized control strategy for energy management based on the optimal state and decision to achieve optimal energy utilization and system performance.

[0116] further, Figure 5 A flowchart of the power distribution control process for a fuel cell system is shown.

[0117] Specifically, the power distribution control process of the fuel cell system includes: real-time monitoring of the operating status of the fuel cell system through sensors, including parameters such as fuel cell stack temperature, pressure, humidity, voltage, and current, as well as the supply of hydrogen and oxygen.

[0118] Specifically, based on the vehicle's power requirements and current driving conditions, the power demand is analyzed to determine the required power output. Based on the monitored system status and load requirements, an appropriate power control strategy is selected, typically including constant power output, constant current output, and constant voltage output.

[0119] Specifically, based on the selected power control strategy, the controller regulates the fuel cell system, including controlling the supply of hydrogen and oxygen, and adjusting the temperature and humidity of the fuel cell stack, in order to achieve the required power output.

[0120] Specifically, during power control, the fuel cell system needs to be protected, including overvoltage protection, undervoltage protection, overcurrent protection, and overtemperature protection, to ensure the safe and stable operation of the system.

[0121] Specifically, the system monitors potential faults and anomalies during operation, diagnoses these faults, and takes appropriate measures based on the diagnostic results to ensure the system's reliability and stability.

[0122] In practical implementation, the power distribution control process of the fuel cell system includes real-time monitoring of the fuel cell system's operating status, including parameters such as fuel cell stack temperature, pressure, humidity, voltage, and current, as well as the supply of hydrogen and oxygen, to achieve efficient energy utilization and precise response to the tractor's power demands. First, sensors monitor various parameters of the fuel cell system in real time, including fuel cell stack temperature, pressure, humidity, voltage, current, and the supply of hydrogen and oxygen. This monitoring data serves as the basis for power distribution control. Second, based on the tractor's power requirements and current driving conditions, the required power output is analyzed to determine the necessary power output. The required power output level is determined based on the tractor's current state and the driving environment. Next, based on the monitored system status and load demands, an appropriate power control strategy is selected, including constant power output, constant current output, and constant voltage output, to determine the fuel cell system's operating mode and output method. According to the power control strategy, the energy management controller adjusts the fuel cell system, including controlling the supply of hydrogen and oxygen, and regulating the temperature and humidity of the fuel cell stack, to achieve the required power output and ensure the system can provide the necessary power output as needed. In addition, the fuel cell system needs protection, including overvoltage protection, undervoltage protection, overcurrent protection, and overtemperature protection, to ensure the safe and stable operation of the system and guarantee its safety and stability. Monitoring for potential faults and anomalies during system operation, fault diagnosis, and taking corresponding measures based on the diagnostic results are crucial to ensuring the system's reliability and stability. This is all done to promptly identify and resolve any problems that may arise during system operation, ensuring the system can continuously and stably provide the required power output.

[0123] further, Figure 6 The control principle diagram of the energy management controller is shown.

[0124] Specifically, the energy management controller's control principle includes: System self-test: The controller performs a self-test upon startup, checking the working status of the controller itself and related sensors to ensure the reliability and safety of system operation. IO signal acquisition: The controller acquires signals through input / output interfaces, including acquiring parameters such as the working status, voltage, and current of various components in the battery system. AD ​​signal acquisition: Analog signals, such as those output by temperature and humidity sensors, are acquired through a digital-to-analog converter. CAN communication signal acquisition: Signals sent by other control units are acquired through the CAN bus interface, enabling information interaction and data sharing with other components. Control signal processing: The controller processes the acquired signals, including analyzing the battery system status and evaluating load requirements to determine the optimal energy management strategy. PWM signal output: The controller converts the output control signal into a PWM signal to control the actuators in the battery system, such as the charge / discharge controller and DC-DC converter. Actuator response: The actuators perform corresponding operations based on the PWM signal output by the controller, such as adjusting the battery charge / discharge state and output voltage, to meet the system's energy management requirements. Fault diagnosis: The controller performs fault diagnosis on the battery system, monitors possible faults and abnormalities during system operation, and takes corresponding measures to ensure the safe and stable operation of the system.

[0125] In practical implementation, the fuel cell tractor energy management controller monitors and controls the status of various system components to achieve efficient energy management and precise response to the tractor's power demands. The specific control process is as follows: First, the controller performs a self-test upon startup, checking the working status of the controller itself and related sensors to ensure the reliability and safety of system operation and to ensure normal operation during startup, avoiding system failures due to controller or sensor malfunctions. Second, the controller acquires signals through the I / O interface, including collecting parameters such as the working status, voltage, and current of various components in the battery system. This acquired data serves as a crucial basis for the controller's energy management, assisting it in understanding the system's current operating status. Then, analog signals are acquired through a digital-to-analog converter (AD converter), including temperature, humidity, and sensor analog signals, allowing the controller to understand the system's environmental conditions and operating parameters. Signals from other control units are acquired through the CAN bus interface, enabling information exchange and data sharing with other components to achieve information sharing and coordinated operation among various components within the system, ensuring the entire system can operate collaboratively. Finally, the controller processes the acquired signals, including analyzing the battery system status and evaluating load demands, to determine the optimal energy management strategy. Based on the analysis results and load requirements, the controller determines the current energy management strategy of the system to meet the power needs of the tractor. The controller converts the output control signal into a PWM signal to control the actuators in the battery system, including the charge / discharge controller and DC / DC converter. Secondly, the output of the PWM signal directly affects each actuator in the battery system, enabling the specific execution of the system's energy management strategy. The actuators perform corresponding operations based on the PWM signal output by the controller, including adjusting the charge / discharge state of the power battery and the output voltage, to meet the system's energy management requirements. Finally, the response of the actuators directly affects the system's energy management effectiveness, ensuring that the system operates according to the controller's requirements. Furthermore, the controller needs to perform fault diagnosis on the battery system, monitor for potential faults and abnormalities during system operation, and take corresponding measures to ensure the safe and stable operation of the system, guaranteeing the reliability and stability of tractor operation.

[0126] further, Figure 7 A power distribution flowchart for a fuel cell electric tractor is shown.

[0127] Specifically, the power distribution process for the fuel cell electric tractor includes: Start-up preparation: Before starting the power process, it is necessary to ensure that the fuel cell system and related components are in normal working condition, including performing system self-checks and checking the working status of the fuel cell stack, hydrogen system, electrical system, and other key components. Starting the fuel cell system: This includes turning on the hydrogen supply system, supplying hydrogen to the fuel cell stack through the hydrogen inlet, and simultaneously introducing air into the oxygen inlet of the fuel cell stack. The fuel cell stack begins to generate electricity, and the power battery system and supercapacitor system start simultaneously. Control system startup: The control system of the fuel cell electric tractor is started, including the energy management controller, drive controller, etc. The controller will begin monitoring the output of the fuel cell system, as well as the motor and other actuators driving the electric tractor. System self-check: The control system performs a self-check procedure to ensure that all sensors, actuators, and other key components are working properly. Operating mode selection: This includes heavy-load mode, medium-load mode, light-load mode, etc. Starting the motor: Once the fuel cell system and control system are working properly, the electric tractor motor is started, enabling the entire fuel cell electric tractor system to operate normally.

[0128] In practical implementation, the power distribution process of a fuel cell electric tractor includes steps from system startup preparation to normal operation. Before starting the power process, it is necessary to ensure that the fuel cell system and components are in normal working condition, including performing system self-checks and checking the working status of the fuel cell stack, hydrogen system, electrical system, and other key components. The steps to start the fuel cell system include opening the hydrogen supply system, supplying hydrogen to the fuel cell stack through the hydrogen inlet, and simultaneously introducing air into the oxygen inlet of the fuel cell stack. The fuel cell stack begins to generate electricity, and the power battery system and supercapacitor system start simultaneously. Control system startup involves activating the fuel cell electric tractor's control system, including the energy management controller and drive controller. The controllers will begin monitoring the output of the fuel cell system, as well as the motor and other actuators driving the electric tractor. The control system performs a self-check procedure to ensure that all sensors, actuators, and other key components are functioning correctly. Operating mode selection includes heavy-load mode, medium-load mode, and light-load mode. Starting the motor is done once the fuel cell system and control system are functioning normally, enabling the entire fuel cell electric tractor system to operate normally.

[0129] In practice, the power distribution process for a fuel cell electric tractor can be described in the following detailed steps:

[0130] Step 1: Startup Preparation: Before starting the electric process, it is essential to ensure that the fuel cell system and related components are in a normal operating condition. This includes performing a system self-test to check the operational status of the fuel cell stack, hydrogen system, electrical system, and other critical components. The system self-test includes checking all sensors, actuators, and other critical components to ensure they are functioning correctly.

[0131] Step 2: Starting the Fuel Cell System. Starting the fuel cell system involves turning on the hydrogen supply system, supplying hydrogen to the fuel cell stack through the hydrogen inlet, and simultaneously introducing air into the oxygen inlet of the fuel cell stack. Inside the fuel cell stack, hydrogen and oxygen undergo a chemical reaction to generate electricity. At the same time, the power battery system and supercapacitor system will also start.

[0132] Step 3: Control System Startup. Start the control system of the fuel cell electric tractor, including the energy management controller, drive controller, etc. These controllers will begin monitoring the output of the fuel cell system, as well as the motor and other actuators driving the electric tractor.

[0133] Step 4: System Self-Check. The control system performs a self-check procedure to ensure that all sensors, actuators, and other critical components are functioning properly. This is an important step in ensuring the safe and reliable operation of the system.

[0134] Step 5: Selecting the Operating Mode. After starting the tractor, you can select different operating modes according to specific operational needs, such as heavy-load mode, medium-load mode, or light-load mode. These modes will affect the performance and energy utilization of the electric tractor.

[0135] Step 6: Meet Preheating Requirements: During preheating, the temperature of the fuel cell stack needs to be monitored to ensure it gradually rises to the appropriate operating temperature range. Once the fuel cell stack reaches the appropriate operating temperature, the system needs to maintain this temperature for a period of time to ensure temperature stability, thus preparing for the normal operation of the fuel cell stack.

[0136] Step 7: Start the motor. Once the fuel cell system and control system are functioning normally, the electric tractor motor can be started to enable the entire fuel cell electric tractor system to operate normally. Starting the motor will give the tractor the ability to perform tasks such as plowing, rotary tilling, and transportation.

[0137] The present invention has the following beneficial effects:

[0138] Fuel cell electric tractors achieve highly efficient energy utilization through a precise energy management system. They can dynamically adjust energy output based on operating conditions and load, maximizing energy efficiency. This effectively reduces exhaust emissions and environmental pollution. Compared to traditional internal combustion engine tractors, fuel cell electric tractors feature zero emissions, significantly contributing to improved air quality and reduced greenhouse gas emissions. Through energy management of the fuel cell system, the entire machine can achieve optimal energy utilization under different operating conditions, improving vehicle operating efficiency, extending driving range, reducing energy consumption, and enhancing the tractor's economics. Furthermore, the effective implementation of this technology helps promote the development and application of clean energy technologies, which is of great significance for achieving sustainable development and addressing climate change, as detailed below:

[0139] High-efficiency energy utilization: Through a precise energy management system, this invention can dynamically adjust energy output and optimize it based on factors such as operating conditions and load, maximizing energy utilization efficiency. Compared to traditional internal combustion engine tractors, fuel cell electric tractors achieve more efficient energy utilization, thereby reducing energy consumption and costs.

[0140] Reduced exhaust emissions: Fuel cell electric tractors are characterized by zero emissions. Compared with traditional internal combustion engine tractors, they can effectively reduce exhaust emissions, reduce environmental pollution, and have a significant positive impact on improving air quality and reducing greenhouse gas emissions.

[0141] Improved operating efficiency and driving range: By managing the energy of the fuel cell system, this invention enables the whole machine to achieve optimal energy utilization under different operating conditions, improve vehicle operating efficiency, extend driving range, thereby reducing energy consumption and improving the economy of the tractor.

[0142] Promoting the development and application of clean energy technologies: The effective implementation of this invention helps to promote the development and application of clean energy technologies, provides important support for achieving sustainable development and addressing climate change, and has positive social and environmental significance.

[0143] The parts of this invention not described in detail are prior art.

[0144] The embodiments selected herein for the purpose of disclosing the inventive objectives are currently considered suitable; however, it should be understood that the invention is intended to include all variations and modifications of the embodiments that fall within the scope of this concept and invention.

Claims

1. An energy management method for a fuel cell electric tractor, characterized in that: The energy management method first determines the stages and states of the problem, divides the problem into multiple stages, and defines the state of each stage; Determine the decision variables and state transition equations, that is, how the decision at each stage transitions to the state at the next stage; Establish an optimization model, define the objective function and constraints to describe the optimization objective of the problem; Using recursive or iterative methods, the optimal state and decision at each stage are calculated to determine the optimal solution to the entire problem. Based on the optimal state and decision, an optimized control strategy for energy management is implemented to achieve optimal energy utilization and system performance. The specific method is as follows: The multi-stage decision-making process divides a specific tractor plowing cycle into N equal stages to find the optimal power allocation ratio of the energy system. The battery system mathematical model employs a dual-polarization reaction equivalent circuit model and a Rint equivalent circuit model to reflect the battery's polarization characteristics. In the energy management strategy, the SOC of the power battery and the SOC of the supercapacitor are used as state variables, their constraint range determined by a common operating range. The fuel cell output power is used as the decision variable, and its constraint range is determined by analyzing the tractor's operating power demand and performance indicators. Simultaneously, the state variables and decision variables are discretized. (1) In the formula, The value of the state variable at time t; The value of the state variable at time t+1; For decision variables; The functional relationship between state variables and decision variables; Therefore, the state transition equation can be expressed as: (2) In the formula, This represents the optimal cost function from the current stage to N; For stage cost function; To find the minimum value of the function; Considering that both high-power and low-power operation of fuel cells have a significant impact on their lifespan, the output mode is divided into three modes: high power demand, normal power demand, and stable output. During the decision-making process, the operating mode of the fuel cell is determined based on the power demand, and the corresponding range of decision variables under different modes is traversed to find the optimal decision. When the output mode is high power demand, the power demand range is: The range of decision variables is When the output mode is normal power demand, the power demand range is: The range of decision variables is When the output mode is stable output, the required power range is: The range of decision variables is In the above formula and These represent the peak power and rated power of the fuel cell, respectively. To optimize the power distribution ratio among the three energy sources, the equivalent hydrogen consumption of the energy system is used as the cost function of the DP algorithm, expressed as: (3) In the formula, The cost function; Hydrogen consumption of fuel cells, in grams; The equivalent hydrogen consumption of the power battery, in grams; The equivalent hydrogen consumption of a supercapacitor is expressed in grams. The equivalent hydrogen consumption of the energy system is expressed as follows: (4) (5) (6) In the formula, , , These are the output power (kW) of the PEMFC, the power battery, and the supercapacitor, respectively. and These are the instantaneous efficiency and average efficiency of the fuel cell, respectively. and These refer to the charging and discharging efficiency of the power battery, respectively. and These refer to the charging and discharging efficiencies of the supercapacitor, respectively. It has the lowest calorific value of hydrogen. The integral symbol is used. Furthermore, the state and decision variables of the energy system should be confined within certain boundary conditions, and should also satisfy the optimization constraints of the driving system. These boundary conditions collectively determine the feasible region of the system's state and decision variables. (7) In the formula, This represents the peak power of the fuel cell. , and For the PEMFC, power battery and supercapacitor, the output power at time t; and The state of charge of the power battery and supercapacitor at time t; and These are the minimum and maximum output power values ​​of the power battery; and These are the minimum and maximum output power values ​​of the supercapacitor; and These are the lower and upper limits of the state-of-charge value for the power battery; and These are the lower and upper limits of the supercapacitor's charged state. By applying the principle of optimality in dynamic programming, the optimal control at each moment is obtained by iterating backward from the final stage, thus yielding the optimal power distribution control strategy for the entire process.

2. The energy management method for a fuel cell electric tractor according to claim 1, wherein the tractor comprises a differential mechanism (1), a left half-shaft (2), a transmission system (4), a drive motor (5), a first DC / AC (6), an energy management controller (7), a supercapacitor (8), a proton exchange membrane fuel cell (9), a power battery (10), a second DC / AC (11), a PTO motor (12), a PTO high / low gear pair (13), a PTO (14), and a right half-shaft (16), characterized in that: The PTO (14) is connected to the PTO high / low gear pair (13), the PTO high / low gear pair (13) is connected to the PTO motor (12), the PTO motor (12) is connected to the second DC / AC (11), the second DC / AC (11) is connected to the energy management controller (7) via a signal, and the energy management controller (7) is connected to the first DC / AC (6), the proton exchange membrane fuel cell (9), the supercapacitor (8) and the power battery (10) via signals respectively. The proton exchange membrane fuel cell (9) and the power battery (10) together form a fuel cell system. The first DC / AC (6) is connected to the drive motor (5), the drive motor (5) is connected to the transmission system (4), the transmission system (4) is connected to the differential mechanism (1), the differential mechanism (1) is connected to the left half shaft (2) and the right half shaft (16) respectively, the left half shaft (2) and the right half shaft (16) are connected to the left drive wheel (3) and the right drive wheel (15) respectively, and the proton exchange membrane fuel cell (9) is connected to the supercapacitor (8) and the power battery (10) respectively.

3. The energy management method for a fuel cell electric tractor according to claim 2, characterized in that: The proton exchange membrane fuel cell (9) includes a hydrogen storage device (901), a hydrogen inlet (902), an oxygen inlet (903), an oxygen supply system (904), a hydrogen exhaust port (905), an oxygen exhaust port (906), a hydrogen processing system (907), an oxygen processing system (908), an anode (909), a proton exchange membrane (910), and a cathode (911). The anode (909) and cathode (911) are respectively provided on the left and right sides of the proton exchange membrane (910). The fuel cell stack consists of a proton exchange membrane (910), an anode (909), and a cathode (911). The hydrogen inlet (902) on the anode (909) is connected to a hydrogen storage device (901), the hydrogen exhaust port (905) on the anode (909) is connected to a hydrogen processing system (907), the oxygen inlet (903) on the cathode (911) is connected to an oxygen supply system (904), and the oxygen exhaust port (906) on the cathode (911) is connected to an oxygen processing system (908).

4. The energy management method for a fuel cell electric tractor according to claim 3, characterized in that: The hydrogen storage device (901) is a hydrogen cylinder.

5. The energy management method for a fuel cell electric tractor according to claim 2, characterized in that: The PTO (14) is connected to the corresponding input shaft of the agricultural machinery equipment.

6. The energy management method for a fuel cell electric tractor according to claim 2, characterized in that: The power battery (10) is a lithium iron phosphate battery, used to buffer the fluctuation of load power.

7. The energy management method for a fuel cell electric tractor according to claim 2, characterized in that: The supercapacitor (8) is used to compensate for the instantaneous response power of the motor.

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