Multi-energy power output system of tractor and control method of multi-energy power output system

Abstract

The invention belongs to the technical field of new energy agricultural machinery equipment, and particularly relates to a multi-energy power output system of a tractor and a control method thereof.The multi-energy power output system comprises a master controller which is in signal connection with a digital control system, a thermal management system, a battery system, a battery management system, a power output system, a suspension control system and a distribution box; the battery system comprises a power battery, a fuel battery and a low-voltage storage battery, and the battery system is electrically connected with the power output system through the distribution box; the suspension control system comprises a lifting arm hydraulic motor, and the power output system comprises a motor controller, a power output motor electrically connected with the motor controller, a direct current output interface used for being connected with direct current equipment and an alternating current output interface used for being connected with an electric agricultural implement. The system can be applied to a traditional fuel tractor platform for rapid battery replacement and energy saving transformation, meanwhile, a new energy tractor can be researched and developed in a matched mode, the cost is reduced, the endurance is prolonged, and the working condition of long operation time is met.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy agricultural machinery equipment, and in particular relates to a multi-energy power output system of a tractor and a control method thereof. Background Art

[0002] At present, the mainstream new energy tractors mainly include pure electric tractors, diesel-electric hybrid tractors and fuel cell tractors. Pure electric tractors use high-voltage power batteries as energy to achieve driving; series diesel-electric hybrid tractors mainly use diesel engines to drive generators to generate electricity, providing the main power source for the electric motor, and the diesel engine does not drive the tractor to drive; the diesel engine of the parallel diesel-electric hybrid tractor drives the generator to generate electricity, and can also drive the mechanical transmission system, so that the electric motor and the diesel engine can drive the tractor together; the driving mode of the hybrid diesel-electric hybrid tractor has both series hybrid drive and parallel hybrid drive, and the driving mode can be selected according to the type of operation to improve energy efficiency.

[0003] The fuel of fuel cells is hydrogen. Compared with the nitrogen oxides and carbon oxides that pollute the air when traditional carbon-containing fuels are burned, the only product of hydrogen combustion is clean and pollution-free water. As a chemical energy carrier, hydrogen has a much greater energy density than traditional batteries, with a power generation capacity of up to 39.39kWh / kg. In addition, compared with the long charging time of batteries, hydrogen charging can be completed in a short time, just like refueling traditional vehicles. It also has the characteristics of abundant reserves, high energy conversion efficiency, and renewability. It is a world-recognized secondary clean energy and has been widely used in the automotive field.

[0004] Electrification is an important trend in the development of agricultural equipment. Green smart manufacturing and electrification have become the key directions for the transformation and upgrading of the construction machinery industry. Enterprises have successively increased their investment in electrification and have launched nearly 100 electric agricultural equipment products. my country's new energy and electric vehicle industry chain is complete, electric agricultural equipment is developing rapidly, and the development of electric agricultural machinery has technical and industrial chain advantages.

[0005] In fuel-powered agricultural machinery and equipment, the power connection and operating parameter adjustment between the chassis and the operating parts are mainly achieved through mechanical parts. The electrification transformation of the operating parts is also an important task in the electrification of agricultural machinery and equipment, including: screening existing agricultural machinery and equipment for electric power input design transformation, researching key technologies such as replacement of mechanical and electrical composite interfaces, and coordinated control of travel-operating devices to achieve integration of operating machinery and equipment with a general electric chassis; researching power distribution and energy management methods that conform to the laws of operating load changes to improve energy utilization efficiency.

[0006] With the rapid development of agricultural mechanization, the types of operations are gradually increasing. The extensive adoption of modern operation methods such as single-operation and compound-operation requires an increasing variety of agricultural implements to be matched with tractors, and the matching methods are also becoming more diverse. In addition to the commonly used rear suspension and rear power take-off, there are also various power take-off devices such as mid-mounted suspension and mid-mounted power take-off.

[0007] During the use of power equipment, since the optimal working temperatures of each subsystem are different, precise energy distribution and heat flow management are required, resulting in a large system structure and complex control. It is necessary to achieve the high integration and collaborative work of the system to optimize the overall performance and energy efficiency, dynamically adapt to the working conditions, reduce energy consumption, and improve the endurance.

[0008] In the existing technology, tractors rely on the mechanical drive of the power take-off system connected to the engine to drive agricultural implements, and the implements will be restricted by the rotational speed or torque of the tractor power take-off drive and the hitch limit. Traditional agricultural implements are driven by the tractor power take-off system, and the power take-off system is directly driven by the engine. The tractor motor output system usually has only two of the three output speeds (540 / 720 / 1000 revolutions per minute); different agricultural implements require different power input speeds, so the driver needs to adjust the power output speed by himself to match the agricultural implements. Therefore, there are certain limitations on the rotational speed or output torque.

[0009] In modern agricultural mechanization operations, the detection of the combined state of agricultural implements and power hosts and the power matching control are crucial. Traditional mechanical power agricultural implements cannot adjust the torque and rotational speed in real time according to the load state, and the real-time detection of motor sensors has high costs and complex installations; although electric agricultural implements judge the state by interacting information through the VCU (vehicle controller), there is a lack of a universal control scheme for the power output motor to mechanical connection type agricultural implements. In addition, the existing technology has a lag in power response when the load suddenly changes, which is likely to cause overload, low energy efficiency, or insufficient operation accuracy. There is an urgent need for a control method that does not require additional sensors, has strong real-time performance, and strong adaptability.

[0010] Using a radial magnetic field motor as the power output motor to drive agricultural implements, agricultural operations usually require high power and large torque, which will inevitably make the weight of the drive motor relatively large and the axial dimension relatively long. However, the tractor rear axle housing and the motor shaft on the market cannot bear the bending moment and shear force brought by the self-weight of the motor, and are prone to cracking. Compared with the radial flux motor, the volume and weight of the axial flux motor with the same power are reduced by about 50%, and it has a wider high-efficiency working range. The disc-type permanent magnet motor has a motor shaft through structure, which is compact and convenient to install, and the direct drive of the motor avoids the transmission of intermediate links and reduces the energy consumption loss. Summary of the Invention

[0011] To solve the above technical problems, the present invention provides a multi-energy power output system and its control method for a tractor.

[0012] The object of the present invention is achieved by the following technical solutions. A multi-energy power output system for a tractor according to the present invention includes a master controller, which includes a memory and a processor. The master controller is signal-connected to the vehicle VCU. The master controller is also signal-connected to a digital control system, a thermal management system, a battery system, a battery management system, a power output system, a suspension control system, and a distribution box. The control end of the digital control system and the sensors for monitoring the battery system, the power output system, and the suspension control system are all signal-connected to the master controller. The battery system includes a power battery, a fuel cell, and a low-voltage battery. The power battery is electrically connected to a charging interface. The battery system is electrically connected to the power output system through the distribution box and is also electrically connected to the suspension control system and the digital control system; the suspension control system includes a lift arm hydraulic motor for driving the lift arm. The power output system includes a motor controller electrically connected to the distribution box, a power output motor electrically connected to the motor controller and used for driving mechanical agricultural implements, a DC output interface for connecting DC electrical equipment, and an AC output interface for connecting electric agricultural implements.

[0013] Further, the low-voltage battery is electrically connected to a solar photovoltaic panel, and the power battery is electrically connected to the low-voltage battery through a DC voltage converter.

[0014] Further, the power battery and the fuel cell are each connected with a corresponding DC voltage converter, and the battery management system controls the current coupling of the power battery and the fuel cell to input into the distribution box.

[0015] Further, the distribution box is provided with a DC voltage converter, a DC-AC converter, a high-voltage positive and negative interface for connecting the battery system; the distribution box is also provided with a heating wire interface for connecting the battery system, a high- and low-voltage AC and DC interfaces for connecting the power output system, a high-voltage power supply interface for connecting the motor controller, and a communication interface for connecting the battery management system.

[0016] A control method for a multi-energy power output system of a tractor includes the following steps:

[0017] Step 1, press the power separator engagement button of the tractor. After the digital control system confirms the start, if the agricultural implement is an electric agricultural implement, after the power cord and signal line of the electric agricultural implement are correctly connected to the AC output interface and the signal interface and confirmed to be correct, control the suspension control system to complete the mechanical connection between the electric agricultural implement and the tractor; if the agricultural implement is a mechanical agricultural implement, directly perform the mechanical connection and connect it to the power output motor;

[0018] Step 2, when the lift arm of the tractor drops to a specified angle, start the low-voltage power-on of the agricultural implement, and perform communication connection and self-check on the agricultural implement;

[0019] Step 3: For electric agricultural machinery, after self-check is completed, power on at high voltage, and transmit the parameters of the electric agricultural machinery and the sensors to the digital control system through the master controller for display, and then proceed to the next step;

[0020] For mechanical agricultural machinery, after self-check is completed, power on at high voltage, and judge the connection state between the mechanical agricultural machinery and the power output motor. If the connection state is that the load is not connected, automatically cut off the high-voltage power supply and prompt the user to check; if it is determined that the connection of the agricultural machinery is abnormal, the lifting arm returns to the original height, automatically cut off the high-voltage power supply and prompt the user to check; if it is determined that the connection of the agricultural machinery is normal, proceed to the next step;

[0021] Step 4: The digital control system asks whether to perform manual mode control. If entering manual mode control, the driver sets the corresponding output mode of the battery system according to the specific technical parameters of the electrical equipment displayed by the digital control system, and at the same time sets the operation parameters; when using electric agricultural machinery, the driver completes the operation path planning of the tractor according to the operation requirements of the supporting agricultural machinery and the field conditions;

[0022] If entering automatic mode control, when using electric agricultural machinery, the master controller judges and reads the running duration, required power and rotational speed of the connected electric agricultural machinery, judges whether the position information of the electric agricultural machinery is in the preset state, automatically completes the setting of the operation parameters of the electric agricultural machinery, and then automatically sets the path planning through information interaction with the vehicle VCU; if using mechanical agricultural machinery, it is necessary to interact with the vehicle VCU to automatically set the trajectory and operation parameters;

[0023] Step 5: The battery management system calculates the required power of the AC output interface or the required power of the power output motor through the manual mode or the automatic control mode, reads the hydrogen storage amount and the SOC of the power battery, and automatically selects the working mode of the battery system according to the required power and the SOC of the power battery;

[0024] Step 6: The thermal management system starts and performs temperature management according to the control program embedded in the master controller;

[0025] Step 7: When it is detected that the agricultural machinery has entered the soil, the master controller performs operation control on the power output system and the suspension control system, selects speed control or torque control according to the operation situation determined in Step 3, and at the same time starts operation fault detection, including resonance detection and stall / overload detection;

[0026] Step 8: Display and store the operation parameters in real time.

[0027] Further, the tractor is connected to mechanical agricultural implements, and the combined state of the power output motor and the mechanical agricultural implements is determined based on the q-axis current of the connected power output motor. The differential signal of the q-axis current feedback is calculated and denoted as the first-order differential signal; the differential signal of the first-order differential signal is calculated and denoted as the second-order differential signal.

[0028] Monitor the first-order differential signal. If the first-order differential signal is close to the limit zero, it is determined that the combined state is that the load is not connected. At this time, the high-voltage power-on is automatically cut off and the user is prompted to check.

[0029] If the first-order differential signal is greater than 0 and the rising slope threshold conforms to the corresponding type of agricultural implement, this data is automatically written through actual measurement and calibrated to the normal range of the first-order differential signal when starting the mechanical agricultural implement, and a time threshold is set for filtering. If the duration for which the first-order differential signal exceeds the normal working range exceeds this time threshold, it is determined that the combined state of the mechanical agricultural implement is abnormal and faulty, the lifting arm returns to the original height, the high-voltage power-on is automatically cut off and the user is prompted to check.

[0030] When using a high-power mechanical agricultural implement in combination or when the mechanical agricultural implement is overloaded, if the first-order differential signal rises above a set multiple of the rated torque and the second-order differential signal approaches 0, and the torque enters a surge state, it is determined that the motor is blocked, the lifting arm returns to the original height, the high-voltage power-on is automatically cut off and the user is prompted to check.

[0031] Further, during the start-up or rotation of the power output motor, the total controller receives the q-axis current, and the q-axis current I a Through a second-order transfer function, the received discrete signal is converted into a continuous signal, and the first-order differential signal dI is obtained q ; then the first-order differential signal dI q is substituted into the second-order transfer function, and the received discrete signal is converted into a continuous signal, and the second-order differential signal ddI can be obtained q ;

[0032] The q-axis current I q The specific working principle of the conversion is as follows: The formula of the second-order transfer function is as follows: Among them, G is the transfer function, s is the complex variable in the Laplace transform, and r is the convergence speed;

[0033] Through the inverse Laplace transform, we get Let y = x1, u = v,

[0034] Then

[0035] That is, substituting the q-axis current into v, the output x2 is the first-order differential signal dI q , similarly, substituting the first-order differential signal dI qSubstitute v, and the output x2 is the second-order differential signal ddI q .

[0036] Furthermore, according to the established three-dimensional weight model of SOC, hydrogen storage capacity, and demand power, the supply current energy is controlled by rules;

[0037] Model M1, Only powered by the power battery;

[0038] Model M2, Only powered by the fuel cell;

[0039] Model M3, The fuel cell supplies power at the normal power, and the rest is supplied by the power battery;

[0040] When the power battery is less than a certain SOC threshold, it prompts that the power is insufficient and automatically shuts down;

[0041] Wherein, is the upper limit value of the output power of the high-efficiency working area of the fuel cell, unit: kW;

[0042] is the lower limit value of the output power of the high-efficiency working area of the fuel cell, unit: kW.

[0043] Furthermore, when it is monitored that dI q > 0, ddI q > 0, the agricultural implement starts to enter the soil; when dI q > 0, ddI q is approximately 0, the load resistance rapidly increases from the time of entering the soil to a slow increase, and at the same time, the angle sensor of the suspension control system monitors that the descending angle enters the working angle, and it is determined that the agricultural implement has completed entering the soil;

[0044] If torque control is selected, when the load is a heavy-duty operation, the change of the load resistance is determined in real time through the first-order differential signal and the second-order differential signal, and the adaptive dynamic optimization of the power of the power output motor is realized;

[0045] If speed control is selected, feedforward compensation control is performed on the differential signal. When dI q ≥ e, it is determined that the load has changed suddenly. Before the load affects the speed, by establishing the compensation relationship between the first-order differential and the agricultural implement, that is, establishing the relationship between dI q and the torque compensation amount dT q , which is dT q = kdI q , the calculated dT q is superimposed on the q-axis torque given value T q1 , that is, T q1 = T q + dT q ;

[0046] During resonance speed regulation, the rotational speed or the first-order differential signal will show a sudden change, and it can be determined that the motor resonates with the agricultural machinery. The torque mode is adjusted to the speed mode to adjust the current rotational speed.

[0047] Furthermore, at the end of the operation, when the master controller detects that the communication with the agricultural machinery is disconnected, or when the driver controls the separation of the electric agricultural machinery, or when the signal value of the specified tractor lift arm angle sensor is greater than a certain value, the master controller sends a shutdown and braking stop signal to the power output motor controller through the CAN bus to cut off the power.

[0048] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0049] 1. The core of the present invention is to provide a power output system for a multi-energy tractor and a corresponding control method, which can be applied to the traditional fuel tractor platform for rapid battery replacement energy-saving transformation. The battery system capacity is designed according to requirements, with a smaller volume and cost. The multi-energy battery management enables the tractor to charge without a fixed location, solving the problem of inconvenient charging. At the same time, it can also be matched with the research and development of new energy tractors, reducing the operation cost compared with pure fuel tractors, and reducing the vehicle procurement cost compared with pure electric tractors, thereby reducing the overall vehicle cost and use cost of the tractor, increasing the endurance, and meeting the working conditions with long operation time.

[0050] 2. The power output system not only meets the control of electric agricultural machinery but also adapts to traditional mechanical agricultural machinery. A reasonable energy management system is designed. The master controller controls the circuit of the battery system and outputs high-voltage alternating current or low-voltage direct current through three paths to match different motors, agricultural machinery, and electrical equipment. It has strong practicability. The combination of intelligent control and digital control system increases the application range and applicability of the motor output system of the tractor. It can not only display the information of each working condition and fault information in real time, facilitating debugging and maintenance, but also makes the operation more convenient and comfortable.

[0051] 3. The control method and steps of the motor output system are safe and intelligent, detecting the combined state in real time and performing power adaptive control. No complex sensors are required. Through the first-order and second-order differential signals of the q-axis current of the power output motor, the combined state detection (load not connected, abnormal, blocked rotation), soil entry state judgment, and power adaptive control (torque / speed mode switching, feedforward compensation, resonance speed regulation) of electric and mechanical power agricultural machinery are realized. The threshold is dynamically calibrated based on the measured data, supporting multiple types of agricultural machinery, improving the real-time performance, accuracy, and energy consumption of the operation, and being applicable to modern agricultural mechanization operation scenarios. The agricultural machinery itself is driven by an electric motor, and the power consumption of the agricultural machinery is separated from the mechanical power output of the tractor. The axial flux disc motor through structure with a smaller axial dimension can easily ensure the structural strength through transmission design while meeting the requirements of compound operation and precision operation.

[0052] The above description is only an overview of the technical solution of the present invention. In order to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the purpose, features and advantages of the present invention more obvious and understandable, the following preferred embodiments are specifically given and described in detail in conjunction with the accompanying drawings as follows. Brief Description of the Drawings

[0053] Figure 1 is a connection block diagram of an embodiment of a multi-energy power output system of a tractor according to the present invention;

[0054] Figure 2a is a connection block diagram of a heat management system in an embodiment of the present invention;

[0055] Figure 2b is a connection block diagram of a heat management system in another embodiment of the present invention;

[0056] Figure 2c is a connection block diagram of a heat management system in still another embodiment of the present invention;

[0057] Figure 3 is an integrated control table of a heat management system in an embodiment of the present invention;

[0058] Figure 4 is a flowchart of the control of the charging method of the low-voltage storage battery in the battery system in an embodiment of the present invention;

[0059] Figure 5a 、 Figure 5b is a mechanical structure diagram of an implementation method of the installation of an axial flux motor structure in an embodiment of the present invention;

[0060] Figure 6 is a flowchart of an embodiment of a control method of a multi-energy power output system of a tractor according to the present invention.

[0061] Reference Signs:

[0062] 1 - Power output flange, 2 - Power output motor, 3 - Coupling, 4 - Rear power output shaft, 5 - Middle power output shaft, 6 - Intermediate shaft, 7 - Support bearing, 8 - Driving gear, 9 - Movable gear, 10 - Driven gear. Detailed Description of the Embodiments

[0063] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0064] As Figure 1 Shown is a connection block diagram of an embodiment of a multi - energy power output system for a tractor according to the present invention. It should be noted that the system of the present invention is applicable to improving existing pure - electric tractors, hybrid tractors, fuel - cell tractors, and traditional fuel - powered tractors. However, since pure - electric tractors and hybrid tractors already have battery packs capable of outputting high - voltage direct current, as a preference, it is most suitable to improve traditional fuel - powered tractors with the system of the present invention. The reasons are as follows: Due to the performance characteristics of large and expensive batteries in pure - electric tractors, the cost of purchasing vehicles in the early stage is relatively large. Considering that traditional fuel - powered tractors do not require batteries and have a lower manufacturing cost compared to pure - electric tractors, but during operation, since fuel is needed to drive agricultural implements and other electrical equipment, the adaptability of agricultural implements is weak, and many limitations described in the previous background technology cannot be solved, resulting in a very high operation cost. In addition, plug - in hybrid tractors have the characteristic of low operation cost, but existing hybrid tractors not only have a complex structure and high cost, but also cannot operate normally to the charging location when the distance from the plug - in hybrid tractor to the urban charging station is far or there is no new - energy vehicle charging facility on the farm.

[0065] Since the chassis of the fuel - powered tractor described in the present invention is similar to that of the fuel - powered tractor in the prior art, which is not the inventive point of the present invention, it will not be elaborated herein.

[0066] Embodiment 1

[0067] A multi - energy power output system for a tractor, which is arranged on the tractor. There are electrical equipment, rear - mounted agricultural implements, and middle - mounted plant protection operation equipment connected to the tractor. The system includes a battery system, a battery management system (BMS), a total controller, a distribution box, a power output system, a suspension control system, a thermal management system, and a digital control system.

[0068] The total controller is communicatively connected to the battery system, BMS, distribution box, power output system, thermal management system, suspension control system, digital control system, and other electrical equipment respectively to control the power output and interpret information from external users and other devices.

[0069] The battery system includes a lithium power battery, a hydrogen fuel cell, and a solar photovoltaic panel. The lithium power battery can also be other forms of power batteries, and the hydrogen fuel cell can also be other forms of fuel cells. The lithium power battery and the hydrogen fuel cell are each connected to a corresponding DC voltage converter (DC / DC). The lithium power battery is converted into direct current through the DC voltage converter and is respectively input into a 12V low-voltage battery and a 48V low-voltage battery. The BMS controls the current coupling input of the lithium power battery and the hydrogen fuel cell to the distribution box. The 12V low-voltage battery and the 48V low-voltage battery are also connected to the distribution box. The distribution box has a DC voltage converter (DC / DC module) and a DC-AC converter (DC / AC module), which divide the current into three outputs; one is converted into alternating current and connected to the AC output interface, which serves as the agricultural machinery AC interface for outputting 380V / 220V alternating current to drive agricultural machinery or other AC devices; one is converted into direct current through the DC voltage converter and connected to the DC output interface for connecting electrical equipment to output direct current. The voltages required by the electrical equipment (which can be low-voltage DC agricultural implements) include 12V, 24V, and 48V. Among them, the 12V and 48V electrical equipment can directly use the corresponding 12V low-voltage battery and 48V low-voltage battery; there is also a high-voltage circuit that is transmitted to the power take-off motor through the motor controller for the tractor power take-off as the power take-off device of the tractor. In this embodiment, the power take-off motor is an axial-flux disc-type power take-off motor.

[0070] The lithium power battery pack is connected to a charging interface for charging the lithium power battery, and the hydrogen fuel cell is connected to a hydrogen refueling port for refueling the hydrogen fuel cell. The lithium power battery and the hydrogen fuel cell are both mounted on the upper side of the side of the tractor chassis frame or in front and behind the tractor to meet the weight balance requirements of the tractor. The solar photovoltaic panel is installed on the vehicle roof.

[0071] The BMS controls the solar photovoltaic panel to supply power to the 12V low-voltage battery and the 48V low-voltage battery. Only when the SOC of the low-voltage battery is lower than 10% (solar energy cannot meet the charging requirements), the lithium power battery charges the low-voltage battery through the DC voltage converter. In other cases, the solar photovoltaic panel supplies power. For the specific process, see Figure 4 as shown. The low-voltage battery is used to supply power to agricultural implements with different voltages alone, such as a 48V seeder, a 12V fertilizer spreader, etc.

[0072] The 12V battery is also used to power on the main controller at a low voltage, supply power to all sensors of the digital control system, and supply power to the thermal management system. The 48V battery is also used to supply power to the lift arm hydraulic motor in the suspension control system. When the power take-off motor consumes a large amount of power, it is used as an auxiliary energy source according to the operation display. The 48V battery enables the power take-off motor to obtain more sufficient power through the converter and the devices in the distribution box that work in coordination with the power take-off motor, improving the operation efficiency.

[0073] The angular position of the lift arm on the tractor is adjusted by the precise rotation of the lift arm hydraulic motor and the geometric relationship of the lifting mechanism.

[0074] The distribution box has high-voltage positive and negative interfaces for connecting the battery system, a DC / AC converter, a DC / DC converter, and conducts power distribution management according to the instructions of the total controller; the distribution box also has a heating wire interface for connecting the battery system, high-voltage and low-voltage AC and DC interfaces for connecting the power output system where the electric agricultural machinery and electrical equipment are located, a high-voltage power supply interface for connecting the motor controller, and a communication interface for connecting the BMS. The total controller is connected to the vehicle VCU and controls the magnitude of the current output of the distribution box according to the power demand of the vehicle VCU and the detected battery system information.

[0075] The motor parameters and battery system parameters are used to calculate the total energy demand of the motor output system by the following formula: The total energy consumption of the tractor TE = E ESS +E ICE .

[0076] Where, TE is the total energy demand, with the unit of kW; E ESS is the energy required by the motor output system, with the unit of Kw; E ICE is the energy required for the tractor to travel, with the unit of Kw.

[0077] The total energy demand of the motor output system is calculated by the following formula:

[0078]

[0079] Where, P ESS is the instantaneous power of the motor output system; P ESS_control is the instantaneous power required by the total controller, sensors and digital control system, and thermal management system; P ESS_task is the instantaneous power required by the power output motor and the agricultural machinery interface during tractor operation; P ESS_liftsystem is the power required by the lift arm hydraulic motor.

[0080] This embodiment conducts regular control of the power supply current energy according to the established three-dimensional weight model of SOC, hydrogen storage capacity, and demand power.

[0081] Model M1, Only powered by lithium power batteries.

[0082] Model M2, Only powered by hydrogen fuel cells.

[0083] Model M3, The fuel cell supplies power at normal power, and the rest is supplied by the power battery.

[0084] When the power battery is less than a certain SOC threshold, it prompts that the power is insufficient and automatically shuts down.

[0085] Among them, is the upper limit value of the output power in the high-efficiency working area of the fuel cell, unit: kW.

[0086] is the lower limit value of the output power in the high-efficiency working area of the fuel cell, unit: kW.

[0087] The BMS regulates the power of the hydrogen fuel cell (a type of fuel cell) and the power lithium battery, and monitors the SOC of the power lithium battery and the low-voltage battery, the hydrogen storage and current status of the hydrogen fuel cell. Among them, the BMS controls the power lithium battery (a type of high-voltage battery or power battery) and the solar photovoltaic panel (PV panel) to charge the 12V / 48V low-voltage battery, and the charging control method is as Figure 4 shown, where SOC 12V is the currently read voltage of the 12V battery, SOC 48V is the currently read voltage of the 48V battery; SOC 12Vmin 、SOC 12Vmax are the minimum and maximum values of the SOC stable interval specified by the manufacturer of the 12V low-voltage battery, SOC 48Vmin 、SOC 48Vmax are the minimum and maximum values of the SOC stable interval specified by the manufacturer of the 48V low-voltage battery; N min is that the output voltage N of the solar photovoltaic panel is lower than the set minimum working voltage.

[0088] The thermal management system also includes a cooling pipeline, an electronically controlled multi-way valve (in this embodiment, an eight-way valve), an electronic pump (electronic pump I, electronic pump II), a heater (PTC), a main and auxiliary radiator (with a fan, including a main radiator, an auxiliary radiator) assembly, a switch assembly A, a switch assembly B, and a coolant tank. The electronic pump and the main and auxiliary radiator assembly are connected to the battery system, the total controller, the power output motor controller, and the power output motor through the cooling pipeline and the electronically controlled multi-way valve to form a closed loop. The coolant in the cooling pipeline and the coolant tank has a low freezing point and a high boiling point (such as ethylene glycol). Using an electronically controlled multi-way valve to replace multiple valves, the main and auxiliary radiators, and the PTC in the traditional system, and integrating multiple cooling pipelines and electronic pumps, not only can simplify the control logic of multiple valves into a single valve, reduce the use of the main and auxiliary radiators and the energy loss of the cooling pipeline, but also reduce the primary energy conversion, thereby improving the energy utilization rate of the system.

[0089] Judge whether the integrated energy saving is adopted for the thermal management mode based on three temperature signals received by the master controller. The three temperature signals are T1, T2, and T3 respectively. T1 is the indication of the sensor for measuring the temperature of the power output motor, T2 is the core temperature of the power battery, and T3 is the temperature of the fuel cell stack obtained by the fuel cell MHS. The temperature signals are displayed on the digital control system. The thermal management system includes two loops, namely the first loop and the second loop. The first loop passes through the master controller, the power output motor and the motor controller assembly and cools them. The second loop regulates the temperature of the power battery and the fuel cell. The master controller heats or cools the power battery and the fuel cell according to the temperature regulation targets of the power battery and the fuel cell and receives the measured temperature. Only the master controller, the power output motor and the motor controller assembly need to be cooled. Since the power battery capacity and fuel cell power adopted by this system are small, the heat supply by the motor can meet the heat demand.

[0090] As Figure 2a shown, by separately collecting the temperature information of the power battery and the fuel cell and the temperature sensor signal of the power output motor, judge whether the integration condition is met through the master controller. If it is met, integrate the thermal management system through the electronic control multi-way valve. Due to the high sensitivity of the performance and life of the power battery and the fuel cell to temperature, the integration control method of the thermal management according to the energy demand and temperature is as Figure 3 shown.

[0091] As Figure 2a shown, both ends of the first loop are respectively connected to port ② and port ① of the electronic control multi-way valve. According to the coolant flow direction, it passes through port ②, the main radiator assembly, electronic pump I, the master controller, the power output motor and the motor controller assembly, and port ① in sequence. The coolant tank is connected to the first loop through a make-up water pipe; both ends of the second loop are respectively connected to port ⑥ and port ⑤. According to the coolant flow direction, it passes through port ⑥, electronic pump II, switch assembly A (when opened, it passes through the power battery to regulate the temperature of the power battery), switch assembly B (when opened, it passes through the fuel cell to regulate the temperature of the fuel cell), and port ⑤ in sequence. In the coolant flow direction, a heating loop is formed by passing through port ③, PTC, and port ④ in sequence, and a secondary radiator loop is formed by passing through port ⑦, the secondary radiator, and port ⑧ in sequence. The thermal management loop control method is integrated in the thermal management system. The loop and the main and secondary radiators are controlled by controlling the operating states of electronic pump I, electronic pump II, switch assembly A, switch assembly B, and the electronic control multi-way valve, so as to realize the temperature regulation of the power battery, the fuel cell, the power output motor and the motor controller assembly. As Figure 2b shown, when using a non-cooled fuel cell, there may be a large difference between the lower limit value c of the power battery temperature and the upper limit value d of the fuel cell temperature. To increase the fuel cell efficiency, a fuel cell additional temperature controller is added to form an additional loop to precisely regulate the temperature of the fuel cell again. As Figure 2cAs shown, when the system only has a power battery, the second loop directly enters the valve port ⑤ after passing through the power battery. The position of the coolant pipe in the first loop can be adjusted as needed, such as Figure 2a , Figure 2b and Figure 2c shown. In other embodiments, the eight-way valve can be changed to a ten-way valve, and the other two valve ports are externally connected to an electronic pump and a fuel cell in sequence, and the temperature of the fuel cell and the power battery are separately regulated to adapt to more working conditions.

[0092] In this embodiment, through the control of the loop by the thermal management system loop control method, multiple loops can be formed, such as Figure 3 shown. According to the integrated determination adjustment (comparing the temperature T1 of the power output motor and the motor controller assembly with the temperature T2 of the power battery and the temperature T3 of the fuel cell, and comparing the temperature T2 of the power battery with its upper limit value a and lower limit value c, and comparing the temperature T3 of the fuel cell with its upper limit value b and lower limit value d), the corresponding loop is selected, and the states of the electronic pump I, electronic pump II, switch assembly A, and switch assembly B are determined, so as to realize the cooling of the power output motor and the motor controller assembly and the temperature regulation of the power battery and the fuel cell. Among them, "√" represents the start or running state, and "×" represents the closed state.

[0093] In Figure 3 , when a certain integrated determination condition is reached, the temperature regulation of the corresponding device is realized according to the loop corresponding to the digital group in the "loop" column, and at the same time, the states of the electronic pump I, electronic pump II, switch assembly A, and switch assembly B are changed. In each "loop", the numbers represent the numbers of each valve port, and the coolant forms a loop in the order of the numbers in the digital group. The "21" in the digital group means that the coolant starts from valve port ② and passes through the main radiator assembly, electronic pump I, total controller, power output motor and motor controller assembly, and valve port ① in sequence. "65" means that the coolant passes through valve port ⑥, electronic pump II, switch assembly A, switch assembly B, and valve port ⑤. "34" means that the coolant passes through valve port ③, PTC, and valve port ④. "78" means that the coolant passes through valve port ⑦, auxiliary radiator, and valve port ⑧ in sequence. The other two adjacent numbers in the digital group represent that the two valve ports are directly connected. For example, "16" means that the coolant goes from valve port ① to valve port ⑥. The following is an example for illustration.

[0094] When the integrated judgment condition of "T1 < T2, T2 < a" is reached, the temperature control target is to cool the power output motor, motor controller assembly, and power battery. Considering that the power output motor has a wide operating range and low thermal sensitivity and can be integratedly controlled, after comparing the cell temperature of the power battery with the target temperature, the operating power of the cooling device (main radiator assembly or electronic pump) can be automatically adjusted according to the target value to meet the power battery thermal management requirements. That is, in 21652, in the electronic control eight-way valve, valve port ① is connected to valve port ⑥, valve port ⑤ and valve port ② are connected, and the coolant flows from electronic pump I through the total controller, power output motor and motor controller assembly, electronic pump II, switch assembly A (passing through the power battery when opened), switch assembly B (passing through the fuel cell when opened), and main radiator assembly in sequence.

[0095] When the equipment operates at high power and the temperature difference continues to increase, and when the first loop for cooling the power output motor and motor controller also cools the power battery, even when the cooling device (electronic pump I and main radiator assembly) operates at full power and switch assembly A is fully opened, if the cell temperature of the power battery is still higher than the dangerous value a, the integrated judgment condition of "T1 < T2, T2 > a" is triggered. That is, in 2178652, valve port ① and valve port ⑦ are connected, valve port ⑧ and valve port ⑥ are connected, valve port ⑤ and ② are connected. After integration, the two loops are combined into the same loop, and a secondary radiator is used to accelerate heat dissipation. The coolant flows from electronic water pump I through the total controller, power output motor and motor controller assembly, secondary radiator, electronic water pump II, switch assembly A (passing through the power battery when opened), switch assembly B (passing through the fuel cell when opened), and main radiator assembly in sequence.

[0096] When "T1 ≥ T2", the temperature T1 of the power output motor and motor controller assembly is greater than the temperature T2 of the power battery. Since the temperature of the power output motor is higher than the cell temperature of the power battery, with the battery system as the priority, when the coolant first flows through the power output motor, the temperature of the coolant may no longer be able to cool the cells of the power battery and may even have the opposite effect. Therefore, it is judged that integrated control cannot be carried out. Therefore, in 212 + 65786, valve port ① and ② are connected, valve port ⑤ and valve port ⑦ are connected, valve port ⑧ and valve port ⑥ are connected, and electronic water pump II is turned on; when T2 > a, higher than the dangerous value, the secondary radiator is turned on; or if it is lower than the dangerous value, "65786" does not connect to the secondary radiator either, that is, 56 is connected, and the secondary radiator is connected when T2 > a. In 212, the coolant flows from electronic water pump I through the total controller, power output motor and motor controller assembly, and main radiator assembly in sequence; in 65786, the coolant flows from electronic water pump II through switch assembly A (passing through the power battery when opened), switch assembly B (passing through the fuel cell when opened), and secondary radiator in sequence.

[0097] When the make-up water pipe is working, for example, T1>T2 and T2<c. Although the temperature of the motor is higher than that of the battery cells of the power battery, in some environments, if only the heat of the power output motor is used to raise the temperature of the battery cells of the power battery, it still cannot ensure that the temperature of the power battery enters the target value c. The PTC needs to be turned on. One option is to choose the non-integrated control 212+65346. The first loop for cooling the power output motor and the second loop for regulating the temperature of the battery system are two independent systems and do not affect each other. In 65346, the coolant flows through the switch assembly A (through the power battery when opened), the switch assembly B (through the fuel cell when opened), and the PTC in sequence from the electronic pump II; or you can choose the integrated control 2134653 (make-up). However, when this make-up water pipe is working, since the coolant after heating the battery is hotter than the temperature of the power output motor, to avoid increasing energy consumption, it no longer flows back into the first loop to cool the motor through the main radiator. After the coolant in the first loop flows into the second loop, it does not flow back into the first loop. In 2134653 (make-up), the coolant flows through the main radiator assembly from the coolant tank, and from the electronic water pump I, it passes through the total controller, the power output motor and the motor controller assembly, the PTC, the switch assembly A (through the power battery when opened), and the switch assembly B (through the fuel cell when opened) in sequence and then flows back into the PTC to continue circulating; or, the coolant flows through the main radiator assembly from the coolant tank, and from the electronic water pump I, it passes through the total controller, the power output motor and the motor controller assembly, part of it flows back into the main radiator assembly and then enters the first loop, and part of it continues to flow into the PTC, the switch assembly A (through the power battery when opened), and the switch assembly B (through the fuel cell when opened) and then flows back into the PTC to continue entering the second loop for circulation. At the same time, the valve ports ① and ② can be set to appropriate openings, which can make a part of the coolant in the first loop enter the second loop to raise the temperature of the power battery, and this will not cause the coolant tank to need to provide a large amount of coolant to the first loop through the liquid filling pipe in a short time, thus reducing the comprehensive energy consumption.

[0098] 65785: The path passes through the switch assembly A (through the power battery when opened), the switch assembly B (through the fuel cell when opened), and the auxiliary radiator in sequence from the electronic water pump 2.

[0099] The total controller receives the temperature information of the power battery cells collected by the BMS in the battery system and the temperature information of the fuel cell respectively, collects the motor temperature on the power output motor, and collects the temperature of the total controller. The signal values received by the total controller are transmitted and displayed on the digital control system in real time.

[0100] In the heating mode, the shortcomings of low PTC heating efficiency and high energy consumption are solved. This integrated control method can introduce the heat generated by the power output motor into the power battery and fuel cell system. When the power battery and fuel cell need to be heated up, this part of the heat will pass through the power battery and fuel cell through the loop to heat up the power battery and fuel cell, reach the appropriate working temperature more quickly, and reduce the heating time of the thermal management system for the power battery. In addition, the temperature of the power output motor will also be reduced through the coolant flowing back from the power battery and fuel system, which will greatly improve the cooling efficiency and cooling effect of the motor and improve the adaptability of the motor to working conditions.

[0101] When cooling is needed, when the temperature sensor detects that the temperature of the power output motor exceeds the target value, the temperature of the battery system exceeds the target value, or the temperature of the fuel cell exceeds the target value, the electronic pump starts; when it continues to exceed a certain threshold, the radiator assembly starts; when any one continues to exceed the limit value, the speed of the electronic pump motor increases to a certain value for emergency cooling and shuts down to ensure safety until the temperature is lower than the limit value.

[0102] The thermal management system controlled by the main controller can automatically start working when the temperature sensor reaches a certain level, and adjust the temperature of the main controller, battery system, motor controller, and power output motor at the same time. There is no need for the thermal management system to remain on all the time, which is more energy-efficient.

[0103] The digital control system includes control terminals such as a display screen in the cab, body switches installed on the tractor, a remote control system, a cloud-based Web control system, and various sensors for monitoring motors, batteries, lifting arms, etc.

[0104] The digital control system displays the tractor's driving status, lifting arm angle position, temperature sensor information, motor speed, motor torque, agricultural implement load, camera recognition information, power output manual control program, etc. on the display screen in the cab and the remote cloud system through CAN bus, gateway and other communication facilities to achieve automatic control or manual control.

[0105] The cloud Web control system can realize remote cloud monitoring, fault warning, equipment maintenance, intelligent data analysis, intelligent control, and comprehensive management. The display screen can display various working conditions and fault information in real time, which is convenient for debugging and maintenance. The body switch follows the operating habits of traditional fuel tractors and can be shut down and powered off in an emergency, which users are more willing to accept. The remote control system makes the operation more convenient and comfortable. You can choose any of the above control methods to control the motor.

[0106] Any one of the cloud Web control system, display screen, remote control system, and body switch in the digital control system can send instructions to the master controller through the CAN bus, and manually or automatically control the power-on startup, lifting position of the lifting arm, driving of the agricultural implement, power-off shutdown, high-voltage power management, and operation status monitoring of the agricultural implement through the master controller.

[0107] The digital control system can also be equipped with the vision system of the tractor, including the weed monitoring system, driving road monitoring system, and safety monitoring system. The driving road monitoring system is used for environmental perception to accurately identify the road position of the agricultural implement. The weed detection system can identify weeds and crops. The safety monitoring system is used to detect obstacles in the road that are harmful to the agricultural implement, and when there are obstacles, it realizes automatic alarm on the display screen and automatic shutdown operation. Weed monitoring, driving road monitoring, and safety monitoring can use cameras.

[0108] When detecting the tillage depth through the digital system, a tillage depth sensor can be used; the rotational speed and torque of the motor can be monitored through a rotational speed sensor and a piezoelectric sensor. The agricultural implement is connected to the lifting arm, and a piezoelectric sensor is set on the lifting arm to detect the load change of the agricultural implement.

[0109] The suspension control system includes an angle sensor and a lifting arm hydraulic motor set on the lifting arm for connecting the agricultural implement. The angle sensor feeds back the working angle change parameters of the lifting arm. The digital control system communicates with the lifting arm hydraulic motor controller through the CAN bus and the master controller. The digital control system realizes automatic connection and power-on of the agricultural implement through the preset angle change or position information embedded in the master controller and controls the angle of the lifting arm.

[0110] For mechanical agricultural implements, the mechanical agricultural implements can be connected to the power output motor, and for electric agricultural implements, the electric agricultural implements can be connected to the agricultural implement AC power interface.

[0111] The master controller stores the control program for the agricultural implement. The control method of the multi-energy power output system of the tractor can be realized through the control program for the agricultural implement. After connecting to the agricultural implement network through the CAN bus, it automatically detects the power consumption data and parameter information of the agricultural implement. The characteristics of its control method are as Figure 6 shown and summarized as follows.

[0112] An embodiment of the control method for the multi-energy power output system of a tractor according to the present invention includes the following steps:

[0113] Step 1: Press the PTO (Power Take-Off) engagement button of the tractor. The digital control system starts to confirm. If the agricultural implement is an electric one, after the power cord and signal line of the electric agricultural implement are correctly connected to the AC power interface and signal interface of the tractor's agricultural implement and confirmed without error, control the suspension control system to complete the mechanical connection between the electric agricultural implement and the tractor. If the agricultural implement is a mechanical one, directly perform the mechanical connection and connect it to the power output motor.

[0114] Step 2: When the lift arm of the tractor drops to the specified angle, start the low-voltage power-on of the agricultural implement and conduct communication connection and self-check on the agricultural implement.

[0115] Step 3: For the electric agricultural implement, after completing the self-check, apply high-voltage power and transmit the parameters of the electric agricultural implement and the relevant parameters of the sensors to the digital control system and display them. Judge the engagement status by interacting information between the electric agricultural implement and the main controller (judge according to the ISO 11783 standard), monitor the status of each system and component such as the electric (current, voltage, power), power system (torque, speed) and working parts of the electric agricultural implement, detect the whole vehicle and report it through the instrument, display screen, voice horn, etc. of the digital control system, and then proceed to the next step.

[0116] For the mechanical agricultural implement, after completing the self-check, apply high-voltage power. Before the lift arm drops to the working state, judge the engagement status between the mechanical agricultural implement and the power output motor. If the engagement status is that the load is not connected, automatically cut off the high-voltage power-on and prompt the user to check. If it is determined that the engagement of the agricultural implement is abnormal, the lift arm returns to the original height, automatically cuts off the high-voltage power-on and prompts the user to check. If it is determined that the engagement of the agricultural implement is normal, proceed to the next step.

[0117] When the tractor is connected to a mechanical agricultural implement, without using a sensor, determine the engagement status between the power output motor and the mechanical agricultural implement based on the q-axis current of the connected power output motor, calculate the differential signal of the q-axis current feedback, denoted as the first-order differential signal; calculate the differential signal of the first-order differential signal, denoted as the second-order differential signal.

[0118] Monitor the first-order differential signal. If the first-order differential signal is abnormally low (close to the limit zero), it is determined that the engagement status is that the load is not connected. At this time, automatically cut off the high-voltage power-on and prompt the user to check. This state indicates that the signal has no disturbance and the signal quickly enters the steady state (such as a constant voltage or a stationary state).

[0119] If the first-order differential signal is greater than 0 and the rising slope threshold conforms to the corresponding type of agricultural machinery (such as rotary tiller, seeder, etc.), the data is automatically written through actual measurement and calibrated in the normal range of the first-order differential signal when starting the mechanical agricultural machinery. At the same time, to avoid load fluctuations such as gear clearances, a time threshold is set for filtering (abnormal signals) to avoid misjudgment. If the duration of the first-order differential signal exceeding the normal working range continuously exceeds this time threshold (such as 0.5 s), it is determined that there is an abnormal engagement state or a fault in the mechanical agricultural machinery, the lifting arm returns to the original height, the high-voltage power-on is automatically cut off, and the user is prompted to check.

[0120] When using a high-power mechanical agricultural machinery in combination or when the mechanical agricultural machinery is overloaded, if the first-order differential signal rises above a set multiple of the rated torque (torque saturation) and the second-order differential signal approaches 0, and the torque enters a surge state, it is determined that the motor is blocked, the lifting arm returns to the original height, the high-voltage power-on is automatically cut off, and the user is prompted to check.

[0121] During the start-up or rotation of the power output motor, the total controller receives the q-axis current, and the q-axis current I q is converted into a continuous signal through a second-order transfer function to obtain the first-order differential signal dI q , and the first-order differential signal dI q is actually the differential signal of the q-axis current. Then, the first-order differential signal dI q is substituted into the second-order transfer function to convert the received discrete signal into a continuous signal, and the second-order differential signal ddI q can be obtained. The second-order differential signal ddI q is actually the differential signal of the first-order differential signal dI q .

[0122] The specific working principle of the conversion of the q-axis current I q is as follows: The formula of the second-order transfer function is as follows: where G is the transfer function, s is the complex variable in the Laplace transform, and r is the convergence rate. The larger r is, the faster the convergence rate. In this embodiment, the value of the convergence rate r can be 1.

[0123] Through the inverse Laplace transform, we get Let y = x1, u = v,

[0124] Then

[0125] That is, substituting the q-axis current into v, the output x2 is the first-order differential signal dI q . Similarly, substituting the first-order differential signal dI q into v, the output x2 is the second-order differential signal ddI q .

[0126] Step 4, the digital control system asks whether to perform manual mode control. If entering the manual mode control, the driver sets the corresponding output mode of the battery system according to the specific technical parameters of the electrical equipment displayed on any operation device in the digital control system, and at the same time sets the output voltage, output peak current, rotation speed, forward and reverse rotation and other operation parameters; when using electric agricultural implements, the driver completes the tractor operation path planning according to the operation requirements of the supporting agricultural implements and the field conditions.

[0127] If entering the automatic mode control, when using electric agricultural implements, the total controller judges and reads the running duration, required power and rotation speed of the connected electric agricultural implements, judges whether the position information of the electric agricultural implements is in the preset state, and automatically completes the setting of the operation parameters of the electric agricultural implements (including forward and reverse rotation, rotation speed, power, position, etc.), and then automatically sets the path planning through information interaction with the vehicle VCU. If it is a mechanical agricultural implement, it is necessary to interact with the vehicle VCU information to automatically set the trajectory, tillage depth, tractor operation speed, etc.

[0128] Step 5, the BMS calculates the required power of the AC interface of the agricultural implement (low voltage is only supplied by the low-voltage battery alone) or the required power of the power output motor through the manual mode or automatic control mode, reads the hydrogen storage amount and the SOC of the power battery, and automatically selects the working mode of the battery system according to the required power and the SOC of the power battery.

[0129] Perform regular control on the supply current energy according to the established three-dimensional weight model of SOC, hydrogen storage amount, and required power.

[0130] Model M1 Only powered by the power battery.

[0131] Model M2 Only powered by the fuel cell.

[0132] Model M3 The fuel cell supplies power at the normal power, and the rest is supplied by the power battery.

[0133] When the power battery is less than a certain SOC threshold, it prompts that the battery power is insufficient and automatically shuts down.

[0134] Among them, is the upper limit value of the output power of the high-efficiency working area of the fuel cell, unit: kW;

[0135] is the lower limit value of the output power of the high-efficiency working area of the fuel cell, unit: kW.

[0136] Step 6, the thermal management system starts and performs temperature management according to the control program embedded in the total controller.

[0137] Step 7: When it is detected that the agricultural implement (electric or mechanical) has completed soil entry, the total controller performs operation control on the power output system and the suspension control system, selects speed control or torque control according to the operation conditions determined in Step 3, that is, automatically selects torque control in the case of high-power heavy load, and automatically selects speed control for small-power precise operation. At the same time, operation fault detection is enabled, including resonance detection and stall / overload detection.

[0138] When it is monitored that dI q > 0 and ddI q > 0, the agricultural implement starts to enter the soil; when dI q > 0 and ddI q is approximately 0, the load resistance rapidly increases from soil entry to a slow increase, and at the same time, the angle sensor of the suspension control system monitors that the descent angle enters the operation angle, and it is determined that the agricultural implement has completed soil entry.

[0139] If torque control is selected, when the load is for heavy-duty operations such as deep plowing, ditch digging, and straw crushing, it is not sensitive to speed. While being able to match different agricultural implements, it optimizes energy efficiency and avoids overload. By continuously determining the change in load resistance through the first-order differential signal and the second-order differential signal, the adaptive dynamic optimization of the power of the power output motor is realized.

[0140] When torque control is performed, state identification needs to be carried out first. In order to exclude accidental factors during state identification, for N consecutive monitoring periods (e.g., N = 5), for example, when the following conditions are met within N monitoring periods where a is the zero threshold of the second-order differential (no sharp mutation in torque), and b is the negative-direction change threshold (which needs to be calibrated according to different agricultural implements), it is determined that the load resistance enters the stage of decreasing growth rate. For example, when the operating environment suddenly changes from hard soil to soft soil or there are different tillage depth changes, etc., the torque is controlled according to the result of state identification to realize the adaptive dynamic optimization of the power of the power output motor.

[0141] According to the collected historical operation data, the I q - load curve database or implanted bench data (such as neural networks and piecewise linear functions, etc.), calculate the current minimum resistance target power, and smoothly transition the I q (or power) to the target power. During this transition process, if the speed fluctuation difference exceeds a certain threshold (e.g., 5%), that is, it is not a heavy-duty operation. To avoid abnormal operations such as overspeed, switch to the speed control mode or withdraw the current command.

[0142] When performing speed control, feedforward compensation control is performed on the differential signal. When the operating environment changes, such as water depth and soil slope, the first-order differential signal increases sharply. This mutation occurs earlier than the obvious fluctuation of the speed. When dI q ≥ e, it is determined that the load has mutated. Before the load affects the speed, by establishing the compensation relationship between the first-order differential and the agricultural implement, that is, establishing dIq The relationship with the torque compensation amount dT q is that dT q = kdI q (model obtained from implant bench data, simulation or operation data), and the calculated dT q is superimposed on the q-axis torque set value T q1 , that is, T q1 = T q + dT q . By quickly adjusting the q-axis current, changing the electromagnetic torque of the motor, compensating for load disturbances, maintaining a constant speed, and achieving precise operations such as sowing, fertilizing, and spraying pesticides.

[0143] During resonance speed regulation, in this embodiment, the vibration frequency is monitored through a vibration sensor or visually to detect whether resonance occurs. The peak frequency of the speed sensor has a high correlation with the fluctuation frequency of the first-order differential signal. To avoid misjudging resonance, the load will also increase during resonance, that is, the speed or the first-order differential signal will also show a mutation and the amplitude will increase significantly. It can be determined that the motor and the agricultural implement are in resonance, and the torque mode is adjusted to the speed mode, and the current speed is adjusted by 8% to avoid the resonance point. When the load rate is high, decelerate, and when the load rate is low, it can be accelerated or decelerated as long as the resonance point is avoided.

[0144] Step eight, the operation parameters are displayed and stored in real time. The driver can read or call them on the digital control system device during the next operation, and they can also be used for differential signals in deep learning or reinforcement learning.

[0145] Step nine, at the end of the operation, when the main controller detects that the communication of the agricultural implement is disconnected, or the driver controls the separation of the electric agricultural implement, or the signal value of the specified tractor lift arm angle sensor is greater than a certain value, the main controller sends a stop and brake signal to the power output motor controller through the CAN bus to cut off the power, so as to avoid damaging the power output shaft and power supply equipment during lifting or separation.

[0146] The main controller includes an electronic device, and the electronic device includes at least one processor and a memory connected to the processor. Among them, the memory is used to store computer programs, and when the processor executes the computer programs in the memory, the electronic device can implement the above control method.

[0147] The present invention also includes a storage medium (such as a memory), and the storage medium carries one or more computer programs. When the one or more computer programs are executed by an electronic device, the electronic device can implement the control method of the multi-energy power output system of the above tractor.

[0148] Please refer to Figure 4 -5 shown, an embodiment of the output mechanical structure of the power output motor of the present invention, but not limited to this figure.

[0149] The power take-off system includes a power take-off flange 1 for facilitating the installation of the power take-off motor 2. One side of the power take-off flange is fixedly arranged at the rear of the tractor body and fixed by welding. The other side of the power take-off flange 1 has a through hole and is installed and fixed to the power take-off motor 2 by bolts, which can be simply disassembled at any time and expose its interior in a larger area for easy inspection, maintenance and replacement. And it ensures that the position of the motor shaft of the power take-off motor 2 is at the outer end of the tractor rear axle housing. The size parameters of the power take-off flange 1 are designed based on this principle.

[0150] The power take-off motor 2 needs to use an axial flux disc motor. Compared with a radial flux motor, it has a smaller volume, lower energy consumption, and can be quickly installed and modified. Thus, it saves the occupied space of the power components and reduces the energy consumption. The motor shaft penetrates through the front and rear parts of the power take-off motor 2. The rear power take-off shaft 4 is integrated with the motor shaft, and the power take-off motor 2 is connected to the agricultural implement at the rear by a direct connection method, omitting the coupling and bearing between the power take-off motor 2 and the rear power take-off shaft 4, which can reduce the axial dimension, reduce the energy loss caused by the additional wear of the power take-off at the same time, and the structure is more compact and beautiful.

[0151] The other end of the motor shaft is connected to the intermediate shaft 6 through a coupling 3. Support bearings 7 are arranged at both ends of the intermediate shaft 6, and the support bearings 7 are arranged on the tractor, so that the intermediate shaft 6 can rotate and can be driven to rotate by the motor shaft. A driving gear 8 is arranged on the intermediate shaft 6. At least two movable gears 9 are also arranged in the tractor body. The movable gears 9 can displace axially. A driven gear 10 is arranged on the middle power take-off shaft 5. Both the driving gear 8 and the driven gear 10 can be meshed with any one of the movable gears 9 at the same time, so that the intermediate shaft 6 can drive the middle power take-off shaft 5 and transmit the power to the middle power take-off shaft 5. According to the shifting requirement, the movable gear 9 meshed with the driving gear 8 and the driven gear 10 is swapped. The power can be shifted by engaging two sets of gear pairs with different tooth number ratios, and the rotational speed requirements of the rear power take-off shaft 4 and the middle power take-off shaft 5 can be respectively realized, so that one motor can work for the middle power take-off and the rear power take-off at the same time.

[0152] Compared with the existing technology, the advantages of the present invention are as follows:

[0153] 1. The core of the present invention lies in providing a power output system for a multi - energy tractor and a corresponding control method. It can be applied to the rapid conversion of traditional fuel tractors into electric - energy - saving tractors. The battery system capacity is designed according to requirements, with smaller volume and cost. The multi - energy battery management enables the tractor to charge without a fixed location, solving the problem of inconvenient charging. At the same time, it can also be matched with the research and development of new - energy tractors, reducing the operation cost compared with pure fuel tractors and reducing the vehicle procurement cost compared with pure electric tractors, thereby reducing the overall cost and use cost of the tractor, increasing the endurance, and meeting the working conditions with long operation time.

[0154] 2. The thermal management system automatically controlled by the master controller is integrally controlled according to the characteristics of the equipment. The sequential circuit design and temperature gradient design are carried out for the thermal management system to make the cooling control more efficient, reducing the energy consumption and use cost of the ordinary new - energy motor output system. Based on the traditional thermal management system architecture, the integrated module of the thermal management system is developed to reduce the system cost and complexity, realizing the comprehensive management of multiple heat sources such as batteries, motors, electronic controls, and the master controller, optimizing the heat flow distribution, and improving the thermal management performance.

[0155] 3. The power output system not only meets the control of electric agricultural implements but also adapts to traditional mechanical agricultural implements. A reasonable energy management system is designed. The master controller controls the circuit of the battery system and outputs high - voltage alternating current or low - voltage direct current through three paths to match different motors, agricultural implements, and electrical equipment. It has strong practicability. The combination of intelligent control and digital control system increases the application range and applicability of the motor output system of the tractor. It can not only display the information of each working condition and fault information in real time, facilitating debugging and maintenance, but also makes the operation more convenient and comfortable.

[0156] 4. The control method and steps of the motor output system are safe and intelligent, detecting the combined state and performing power adaptive control in real time. Without complex sensors, through the first - order and second - order differential signals of the q - axis current of the power output motor, the combined state detection (load not connected, abnormal, blocked rotation), soil - entry state judgment, and power adaptive control (torque / speed mode switching, feed - forward compensation, resonance speed regulation) of electric and mechanical power agricultural implements are realized. Based on the measured data, the threshold is dynamically calibrated, supporting multiple types of agricultural implements, improving the operation real - time performance, accuracy, and energy consumption efficiency, and being applicable to modern agricultural mechanization operation scenarios. When the agricultural implement is driven by an electric motor, the power consumption of the agricultural implement is separated from the mechanical power output of the tractor. The axial - flux disk - type motor through - structure with a smaller axial dimension can easily ensure the structural strength through transmission design while meeting the requirements of double - operation and precision operation.

[0157] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A multi-energy power output system for a tractor, comprising a master controller, the master controller including a memory and a processor, characterized in that: The total controller is signal-connected to the vehicle VCU. The total controller is also signal-connected to the digital control system, the thermal management system, the battery system, the battery management system, the power output system, the suspension control system, and the distribution box. The control end of the digital control system and the sensors for monitoring the battery system, the power output system, and the suspension control system are all signal-connected to the total controller. The battery system includes a power battery, a fuel cell, and a low-voltage battery. The power battery is electrically connected to the charging interface. The battery system is electrically connected to the power output system through the distribution box and is also electrically connected to the suspension control system, the thermal management system, and the digital control system; The suspension control system includes a lift arm hydraulic motor for driving the lift arm. The power output system includes a motor controller electrically connected to the distribution box, a power output motor electrically connected to the motor controller and used to drive mechanical agricultural implements, a DC output interface for accessing DC electrical equipment, and an AC output interface for accessing electric agricultural implements.

2. The multi - energy power output system of a tractor according to claim 1, characterized in that: The low-voltage battery is electrically connected to the solar photovoltaic panel. The power battery is electrically connected to the low-voltage battery through a DC voltage converter.

3. The multi - energy power output system of a tractor according to claim 1, wherein: The power battery and the fuel cell are each connected with a corresponding DC voltage converter. The battery management system controls the current coupling of the power battery and the fuel cell to input into the distribution box.

4. A multi-energy power output system for a tractor according to claim 1, characterized in that: The distribution box is provided with a DC voltage converter, a DC-AC converter, high-voltage positive and negative interfaces for connecting the battery system; The distribution box is also provided with a heating wire interface for connecting the battery system, high- and low-voltage AC and DC interfaces for connecting the power output system, a high-voltage power supply interface for connecting the motor controller, and a communication interface for connecting the battery management system.

5. A control method for a multi - energy power output system of a tractor, characterized in that: It includes the following steps: Step 1, press the power separator engagement button of the tractor. After the digital control system confirms the start, if the agricultural implement is an electric agricultural implement, after the power cord and signal line of the electric agricultural implement are correctly connected to the AC output interface and the signal interface and confirmed to be correct, control the suspension control system to complete the mechanical connection between the electric agricultural implement and the tractor; If the agricultural implement is a mechanical agricultural implement, directly perform the mechanical connection and connect it to the power output motor. Step 2, when the lift arm of the tractor drops to a specified angle, start the low-voltage power-on of the agricultural implement, and perform communication connection and self-check on the agricultural implement. Step 3, for electric agricultural implements, after completing the self-check, perform high-voltage power-on, and transmit the parameters of the electric agricultural implements and the parameters of the sensors to the digital control system through the total controller and display them, and then proceed to the next step; For mechanical agricultural implements, after completing the self-check, perform high-voltage power-on, and judge the engagement state between the mechanical agricultural implement and the power output motor. If the engagement state is that the load is not connected, automatically cut off the high-voltage power-on and prompt the user to check; If it is determined that the combination of the agricultural implement is abnormal, the lift arm returns to the original height, automatically cuts off the high-voltage power-on and prompts the user to check; If it is determined that the combination of the agricultural implement is normal, proceed to the next step. Step 4: The digital control system asks whether to perform manual mode control. If entering the manual mode control, the driver sets the corresponding output mode of the battery system according to the specific technical parameters of the electrical equipment displayed by the digital control system, and sets the operation parameters at the same time. When using electric agricultural implements, the driver completes the operation path planning of the tractor according to the operation requirements of the supporting agricultural implements and the field conditions. If entering the automatic mode control, when using electric agricultural implements, the master controller judges and reads the running duration, required power and rotation speed of the connected electric agricultural implements, judges whether the position information of the electric agricultural implements is in the preset state, automatically completes the setting of the operation parameters of the electric agricultural implements, and then automatically sets the path planning through the information interaction with the vehicle VCU. If using mechanical agricultural implements, it is necessary to interact with the vehicle VCU to automatically set the trajectory and operation parameters. Step 5: The battery management system calculates the required power of the AC output interface or the required power of the power output motor through the manual mode or the automatic control mode, reads the hydrogen storage amount and the SOC of the power battery, and automatically selects the working mode of the battery system according to the required power and the SOC of the power battery. Step 6: The thermal management system starts and performs temperature management according to the control program embedded in the master controller. Step 7: When it is detected that the agricultural implement has entered the soil, the master controller performs operation control on the power output system and the suspension control system, selects speed control or torque control according to the operation conditions determined in Step 3, and simultaneously enables operation fault detection, including resonance detection and stall / overload detection. Step 8: The operation parameters are displayed and stored in real time.

6. A control method for a multi-energy power output system of a tractor according to claim 5, characterized in that: When the tractor is connected with mechanical agricultural implements, the combined state of the power output motor and the mechanical agricultural implements is determined based on the q-axis current of the connected power output motor, and the differential signal of the q-axis current feedback is calculated, denoted as the first-order differential signal; the differential signal of the first-order differential signal is calculated, denoted as the second-order differential signal. Monitor the first-order differential signal. If the first-order differential signal is close to the limit zero, it is determined that the combined state is that the load is not connected. At this time, the high-voltage power-on is automatically cut off and the user is prompted to check. If the first-order differential signal is greater than 0 and the rising slope threshold conforms to the corresponding type of agricultural implement, this data is automatically written through actual measurement and calibrated to the normal range of the first-order differential signal when starting the mechanical agricultural implement, and a time threshold is set for filtering. If the duration of the first-order differential signal exceeding the normal working range continuously exceeds this time threshold, it is determined that there is an abnormal combined state or a fault in the mechanical agricultural implement, the lifting arm returns to the original height, the high-voltage power-on is automatically cut off and the user is prompted to check. When using a high-power mechanical agricultural implement in combination or when the mechanical agricultural implement is overloaded, if the first-order differential signal rises above a set multiple of the rated torque and the second-order differential signal approaches 0, and the torque enters a surge state, it is determined that the motor is stalled, the lifting arm returns to the original height, the high-voltage power-on is automatically cut off and the user is prompted to check.

7. A control method for a multi-energy power output system of a tractor according to claim 6, characterized in that: During the startup or rotation of the power output motor, the total controller receives the q-axis current, and the q-axis current I q is converted into a continuous signal through a second-order transfer function for the received discrete signal, and a first-order differential signal dI q is obtained; then the first-order differential signal dI q is substituted into the said second-order transfer function to convert the received discrete signal into a continuous signal, and thus a second-order differential signal ddI q is obtained; q-axis current I q The specific working principle of the conversion is as follows: The second-order transfer function formula is as follows: where G is the transfer function, s is the complex variable in the Laplace transform, and r is the convergence rate; Obtained by inverse pull transformation Let y = x1, u = v then That is, substitute the q-axis current into v, and the output x2 is the first-order differential signal dI q , similarly, substitute the first-order differential signal dI q into v, and the output x2 is the second-order differential signal ddI q .

8. The control method of a multi - energy power output system of a tractor according to claim 5, characterized in that: According to the established three - dimensional weight model of SOC, hydrogen storage quantity, and demand power, the power of the power supply current is controlled regularly; Model M1, Powered only by the power battery; Model M2, Powered only by a fuel cell; Model M3, The fuel cell supplies power at normal power, and the rest is supplied by the power battery; When the power battery is less than a certain SOC threshold, it prompts that the power is insufficient and shuts down automatically; Among them, is the upper limit value of the output power in the high-efficiency working area of the fuel cell, unit: kW; It is the lower limit value of the output power in the high-efficiency working area of the fuel cell, unit: kW.

9. The control method of a multi - energy power output system of a tractor according to claim 7, characterized in that: When dI is monitored q > 0, ddI q > 0, the agricultural implement starts to enter the soil; when dI q > 0, ddI q is approximately 0, the load resistance rapidly increases from the soil entry to a slow increase, and at the same time, the angle sensor of the suspension control system monitors that the descent angle enters the working angle, and it is determined that the agricultural implement has completed the soil entry; If torque control is selected, when the load is for heavy - duty operation, the change of load resistance is determined in real time through the first - order differential signal and the second - order differential signal, and the adaptive dynamic optimization of the power of the power output motor is realized; If the rotational speed control is selected, a feedforward compensation control is performed on the differential signal. When dI q ≥e, it is determined that the load has changed suddenly. Before the load affects the rotational speed, by establishing a compensation relationship between the first-order differential and the agricultural implement, that is, by establishing the relationship between dI q and the torque compensation amount dT q , which is dT q =kdI q , the calculated dT q is superimposed on the q-axis torque reference value T q1 , that is, T q1 =T q +dT q ; During resonance speed regulation, the rotation speed or the first - order differential signal will have a sudden change, and it can be determined that the motor and the agricultural machinery are in resonance. The torque mode is adjusted to the speed mode to adjust the current rotation speed.

10. The control method of a multi - energy power output system of a tractor according to claim 5, characterized in that: At the end of the operation stage, when the main controller detects that the communication with the agricultural machinery is disconnected, or when the driver controls the separation of the electric agricultural machinery, or when the signal value of the specified tractor lift arm angle sensor is greater than a certain value, the main controller sends a signal to stop and brake the power output motor to stop rotating through the CAN bus, realizing power cut - off.

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