Topology and operation mode of intelligent driving series-parallel hybrid tractor

Abstract

The present invention discloses a topological structure and operation mode of a smart driving hybrid tractor, including a power transmission system and an intelligent driving perception system. The power transmission system includes power batteries, AC / DC, DC / DC, diesel engines, motors, traction motors, planetary gears, clutches, transmissions, PTO assemblies, central transmission devices, vehicle controllers and other components; the intelligent driving perception system includes low-voltage batteries, industrial computers, speed sensors, gyroscopes, laser radars, binocular cameras and other components. The tractor adopts a hybrid system with multiple operation modes; the diesel engine always works in a high efficiency zone, power is divided and converged, and the traction motor, diesel engine and motor are driven in a coordinated manner, with high comprehensive energy utilization, energy saving and environmental protection; it has two driving modes, intelligent driving and manual driving, which can enable the tractor to operate normally in various complex environments and road conditions, and also greatly liberate the tractor driver.

Description

Technical Field

[0001] The present invention belongs to the technical field of intelligent driving hybrid power tractors, and in particular relates to a topological structure and an operating mode of an intelligent driving series-parallel hybrid power tractor. Background Art

[0002] my country is a large agricultural country, and the number of agricultural machinery such as tractors has increased year by year. The energy consumption and pollutant emissions of traditional fuel tractors have become the focus and difficulty of energy conservation and emission reduction; the working environment of tractors is harsh and noisy, so it is urgent to liberate the hands of agricultural machinery drivers and develop intelligent driving tractors. With the development and maturity of intelligent driving and hybrid vehicle technologies, intelligent driving hybrid electric tractors have gradually entered the field of agricultural machinery.

[0003] In a series hybrid tractor, there is no direct mechanical connection between the diesel engine and the wheels. The traction motor provides all the power required by the vehicle. The energy utilization rate of the whole machine is low. It is mainly suitable for tractor operating conditions with frequent starting and low traction power requirements. In a parallel hybrid tractor, the diesel engine and the traction motor can work independently, but the working state of the diesel engine fluctuates greatly, cannot stably work in the high efficiency area, and has poor emissions. Summary of the invention

[0004] In view of the shortcomings of series hybrid power systems and parallel hybrid power systems, the purpose of the present invention is to propose a series-parallel hybrid power tractor topology structure and operation mode integrating intelligent driving technology, which has the advantages of energy saving and emission reduction, high energy utilization rate of the whole machine, and diverse driving modes, while also liberating agricultural machinery drivers.

[0005] like Figure 1As shown, the topological structure of a smart driving hybrid tractor proposed by the present invention includes a power transmission system and an intelligent driving perception system, wherein the power transmission system includes a power battery, an AC / DC module, a DC / DC module, a diesel engine, a motor, a traction motor, a planetary gear, a clutch, a transmission, a steering pump, a PTO assembly (PTO stands for power output shaft), a central transmission device, a vehicle controller and other components; the intelligent driving perception system includes a low-voltage battery, an industrial computer, a speed sensor, a gyroscope, a laser radar and a binocular camera and other components. The power battery is electrically connected to the low-voltage battery through the DC / DC module to charge the low-voltage battery; the power battery is connected to the traction motor and the motor through the AC / DC module to realize energy exchange between the traction motor and the motor; the low-voltage battery is electrically connected to the laser radar, the binocular camera, the speed sensor, the gyroscope, the vehicle controller and the industrial computer respectively to provide power to the aforementioned components. The laser radar is connected to the industrial computer via Ethernet and is used to detect the distance between the tractor body and obstacles. The binocular camera is connected to the industrial computer via the CAN bus and is used to collect information about objects on the tractor body's route. The gyroscope is used to collect angle signals such as the roll and pitch of the tractor body in multi-degree-of-freedom space; the speed sensor is used to collect the tractor's travel speed. The diesel engine, planetary gear, motor, power steering pump, clutch, transmission, traction motor, PTO assembly (PTO stands for power output shaft), and central transmission device use mechanical connections to transmit power. The central transmission device drives the rear wheels to achieve the travel of the hybrid tractor; the transmission is located between the planetary gear and the central transmission device. The power of the diesel engine and the traction motor is first superimposed and synthesized by the planetary gear, and then transmitted to the transmission for speed reduction and torque increase, and finally transmitted to the central transmission device. The vehicle controller is connected to the power battery, low-voltage battery, gyroscope, speed sensor, diesel engine, clutch, power steering pump, traction motor, motor, PTO assembly (PTO stands for power output shaft), transmission, AC / DC module, and DC / DC module through the CAN bus respectively; the vehicle controller also obtains the tractor's operating condition information from the industrial computer through UDP communication, performs optimization control, and realizes energy-saving operation of the tractor.

[0006] The binocular camera, based on the principle of human binocular recognition of objects, can simulate human visual imaging to perform 3D imaging, compare the different image signals obtained by the two cameras, and identify objects more reliably. The laser radar is used to detect road conditions and obstacles during the driving of the tractor, and sense the distance between the surrounding object information and the tractor in real time. The transmission outputs three parts of power, which are used as power input for the central transmission device, the PTO assembly (PTO stands for power output shaft), and the steering power pump. Through the combination of the diesel engine and the motor, the power output of the diesel engine is reasonably distributed, so that the diesel engine works in the high efficiency area and the capacity of the diesel engine is fully utilized; when the diesel engine works in the high efficiency area and the output power is excessive, the motor converts the excess energy into electrical energy to charge the power battery, ensuring the efficient operation of the tractor. The planetary gear is used as a coupling device for the traction motor and the output power of the diesel engine. It can not only realize the simultaneous operation of the diesel engine and the traction motor, but also realize the operation of the diesel engine or the traction motor separately. Power steering pump: when steering is required, the vehicle controller converts the steering wheel angle command into an oil pressure signal and outputs it to the power steering pump. The power steering pump generates high-pressure oil and achieves precise assistance by controlling the oil pressure to push the front wheels to steer, reducing the driver's operating intensity and improving the vehicle's maneuverability.

[0007] The present invention adopts a hybrid power system with various operation modes, which can be adapted to various working conditions. If the diesel engine is turned on, the diesel engine always works in the high efficiency zone, and the diesel engine output power is P 油 , the output torque is T 油 ; The maximum output power of the traction motor is P 牵引max , the maximum output torque is T 牵引max ; Preset maximum power threshold SOC max The SOC value is 80% of the full charge state, and the preset minimum power threshold SOC min is 30% SOC value of full charge state. Then the intelligent driving series-parallel hybrid tractor has the following operation modes:

[0008] (1) Traction motor drive mode: When the vehicle's traction demand power P is less than the maximum output power P of the traction motor 牵引max , the required torque T is less than the maximum output torque T of the traction motor 牵引max When the power battery is higher than the preset maximum power threshold SOC max , the diesel engine and the electric motor are turned off, the traction motor is turned on, and the traction motor drives the vehicle alone;

[0009] (2) Series combined drive mode: When the vehicle is in a state where the traction demand power P is less than the maximum output power P of the traction motor 牵引max , the required torque T is less than the maximum output torque T of the traction motor 牵引maxWhen the power battery is higher than the preset minimum power threshold SOC min , then the diesel engine, motor, and traction motor are turned on, the diesel engine drives the motor to generate electricity, the motor and the power battery jointly supply power to the traction motor, and the traction motor drives the vehicle alone;

[0010] (3) Series driving charging mode: When the vehicle's traction demand power P is less than the maximum output power P of the traction motor 牵引max , the required torque T is less than the maximum output torque T of the traction motor 牵引max When the power battery is lower than the preset minimum power threshold SOC min , then the diesel engine, motor, and traction motor are turned on, and the diesel engine output power P 油 All drive motors generate electricity, which charges the power battery and supplies power to the traction motor, which drives the vehicle alone.

[0011] (4) Parallel joint drive mode: When the vehicle is in a state where the traction demand power P is greater than the maximum output power P of the traction motor 牵引max , the required torque T is greater than the maximum output torque T of the traction motor 牵引max When the traction demand power is greater than the diesel engine output power P 油 , the diesel engine and traction motor are turned on, the motor is turned off, and the diesel engine and traction motor jointly drive the vehicle to work;

[0012] (5) Parallel driving charging mode: When the vehicle's traction demand power P is less than the diesel engine output power P 油 , the required torque T is less than the maximum output torque T of the traction motor 牵引max When the power battery is lower than the preset minimum power threshold SOC min , the diesel engine and the motor are turned on, the traction motor is turned off, and the diesel engine drives the vehicle alone while charging the power battery through the motor;

[0013] (6) Hybrid joint drive mode: When the vehicle's traction demand power P is greater than the diesel engine output power P 油 and the maximum output power of the traction motor P 牵引max The sum of the required torque T is greater than the diesel engine output torque T 油 and the maximum output torque of the traction motor T 牵引max When the working condition is equal to the sum of the above, the diesel engine, motor and traction motor are turned on, the motor is used as a motor, and the diesel engine, motor and traction motor jointly drive the vehicle to work;

[0014] (7) Deceleration / Braking Energy Recovery Mode: When the vehicle is in a deceleration or braking condition, the diesel engine and traction motor are shut down and the motor is used as a generator to recover the energy generated during the deceleration or braking process.

[0015] The intelligent driving parallel-parallel hybrid tractor of the present invention provides two driving modes: intelligent driving and manual driving. The tractor operation control process is as follows: Figure 2 As shown. In relatively regular fields with few obstacles, when the environmental information collected by the perception information module meets the intelligent driving conditions, the intelligent driving mode is started, the starting point and the end point are set, and the tractor can operate in the field according to the preset path. The perception information module includes laser radar, binocular camera, and gyroscope. The laser radar and binocular camera are responsible for collecting the driving environment information required by the intelligent driving tractor, providing a reliable decision-making basis for the safe driving of the intelligent driving tractor; the gyroscope is responsible for collecting the state information of the tractor body in the posture space to ensure that the intelligent driving tractor can operate continuously and stably; the speed sensor is responsible for collecting the travel speed information of the intelligent driving tractor to ensure that the tractor's driving speed is reasonable. The vehicle controller collects the whole machine operation execution information through CAN bus and UDP communication and performs data processing and analysis, and coordinates and reasonably controls the power transmission system (traction motor, motor, clutch, diesel engine, steering power pump) and intelligent driving perception system of the intelligent driving tractor to ensure that the intelligent driving tractor operates according to the preset requirements. When the weather conditions are bad, the intelligent driving perception system has poor recognition effect, or the field road conditions are complex, rugged, and there are many obstacles, and the collected environmental information cannot meet the conditions of the intelligent driving mode, it can be switched to manual driving mode. The manual driving mode is similar to that of a general parallel-parallel hybrid tractor.

[0016] The beneficial effects of the present invention are:

[0017] (1) The hybrid power system integrates intelligent driving technology. The diesel engine works in the high-efficiency area, the power is divided and merged, and the traction motor, diesel engine and electric motor work in a coordinated manner, with high comprehensive energy utilization rate and energy saving and environmental protection.

[0018] (2) It has two driving modes: intelligent driving and manual driving, which enables the tractor to operate normally in various complex environments and road conditions, reducing the driver's fatigue. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A topological structure diagram of the intelligent driving series-parallel hybrid power tractor of the present invention;

[0020] Figure 2 It is a flow chart of tractor operation control of the present invention.

[0021] Figure 1In the middle: 1 is the ring gear of the planetary gear set, which is mechanically connected to the power coupling shaft of the diesel engine and the motor; 2 is the sun gear of the planetary gear set, which is mechanically connected to the power output shaft of the traction motor; 3 is the planetary gear of the planetary gear set, which is mechanically connected to the power input end of the transmission. DETAILED DESCRIPTION

[0022] The following specific examples are given to further clearly, completely and in detail illustrate the technical solution of the present invention. This example is the best example based on the technical solution of the present invention, but the protection scope of the present invention is not limited to the following examples.

[0023] The topological structure of an intelligent driving series-parallel hybrid tractor of the present invention is described in detail by taking a certain intelligent driving series-parallel hybrid tractor as an example. Figure 1The topological structure of this tractor includes a power transmission system and an intelligent driving perception system, wherein the power transmission system includes a power battery, an AC / DC module, a DC / DC module, a diesel engine, a motor, a traction motor, a planetary gear, a clutch, a transmission, a power steering pump, a PTO assembly (PTO stands for power output shaft), a central transmission device, a vehicle controller and other components. The diesel engine and the motor are matched. The motor adopts a through-shaft motor and is coupled with the diesel engine for torque. The torque is transmitted to the transmission after the output power of the planetary gear and the traction motor is coupled through the clutch. The power output end of the transmission is mechanically connected to the power steering pump, the central transmission device and the PTO assembly respectively; the intelligent driving perception system includes a low-voltage battery, an industrial computer, a speed sensor, a gyroscope, a lidar and a binocular camera and other components. The power battery is electrically connected to the low-voltage battery through the DC / DC module to charge the low-voltage battery; the power battery is connected to the traction motor and the motor through the AC / DC module to realize the energy exchange between the traction motor and the motor; the low-voltage battery is electrically connected to the laser radar, binocular camera, speed sensor, gyroscope, vehicle controller, and industrial control machine to provide power to the aforementioned components. The laser radar is connected to the industrial control machine through Ethernet and is used to detect the distance between the tractor body and obstacles. The binocular camera is connected to the industrial control machine through the CAN bus and is used to collect object information on the tractor body's route. The gyroscope is used to collect the angle signals of the tractor body's roll, pitch, etc. in multi-degree-of-freedom space; the speed sensor is used to collect the tractor's travel speed. The diesel engine, planetary gear, motor, power steering pump, clutch, transmission, traction motor, PTO assembly (PTO stands for power output shaft), and central transmission device are connected mechanically to transmit power. The central transmission device installed on the rear wheel axle drives the rear wheel to realize the movement of the hybrid tractor. The aforementioned mechanical connection method is a prior art and is only briefly described here. The transmission is located between the planetary gear and the central transmission device. The power of the diesel engine and the traction motor is first superimposed and synthesized by the planetary gear, and then transmitted to the transmission for speed reduction and torque increase, and finally transmitted to the central transmission device. The vehicle controller is connected to the power battery, low-voltage battery, gyroscope, speed sensor, diesel engine, clutch, power steering pump, traction motor, motor, PTO assembly (PTO stands for power output shaft), transmission, AC / DC module, and DC / DC module through the CAN bus. During the operation of the tractor, the vehicle controller reads the working status and data of the aforementioned components through the CAN bus. The vehicle controller also obtains the working condition information of the tractor from the industrial computer through UDP communication, performs optimization control, and realizes energy-saving operation of the tractor.

[0024] The topology of this intelligent driving hybrid tractor uses binocular cameras. Based on the principle of human binocular recognition of objects, it can simulate human visual imaging to perform 3D imaging, compare different image signals obtained by two cameras, and identify objects more reliably. Lidar is used to detect road conditions and obstacles during the driving of the tractor, and sense the distance between the surrounding object information and the tractor in real time. The transmission outputs three parts of power, which are used as power input for the central transmission device, PTO assembly (PTO stands for power output shaft), and steering power pump. Through the combination of diesel engine and motor, the power output of the diesel engine is reasonably distributed, so that the diesel engine works in the high efficiency area and fully utilizes the capacity of the diesel engine; when the diesel engine works in the high efficiency area and the output power is excessive, the motor converts the excess energy into electrical energy to charge the power battery, ensuring the efficient operation of the tractor. The planetary gear is used as a coupling device for the traction motor and the output power of the diesel engine. It can not only realize the simultaneous operation of the diesel engine and the traction motor, but also realize the operation of the diesel engine or the traction motor separately. Power steering pump: when steering is required, the vehicle controller converts the steering wheel angle command into an oil pressure signal and outputs it to the power steering pump. The power steering pump generates high-pressure oil and achieves precise assistance by controlling the oil pressure to push the front wheels to steer, reducing the driver's operating intensity and improving the vehicle's maneuverability.

[0025] The following is a detailed explanation of the intelligent driving hybrid tractor operating in the field as an example.

[0026] This tractor adopts a hybrid power system with various operation modes, which can adapt to various working conditions. If the diesel engine is turned on, it will always work in the high efficiency area, and the output power of the diesel engine is P 油 , the output torque is T 油 ; The maximum output power of the traction motor is P 牵引max , the maximum output torque is T 牵引max ; Preset maximum power threshold SOC max The SOC value is 80% of the full charge state, and the preset minimum power threshold SOC min The SOC value is 30% of the full charge state. This tractor has the following seven basic operating modes:

[0027] (1) Traction motor drive mode: When the vehicle's traction demand power P is less than the maximum output power P of the traction motor 牵引max , the required torque T is less than the maximum output torque T of the traction motor 牵引max When the power battery is higher than the preset maximum power threshold SOC max , the diesel engine and the electric motor are turned off, the traction motor is turned on, and the traction motor drives the vehicle alone;

[0028] (2) Series combined drive mode: When the vehicle is in a state where the traction demand power P is less than the maximum output power P of the traction motor 牵引max , the required torque T is less than the maximum output torque T of the traction motor 牵引max When the power battery is higher than the preset minimum power threshold SOC min , then the diesel engine, motor, and traction motor are turned on, the diesel engine drives the motor to generate electricity, the motor and the power battery jointly supply power to the traction motor, and the traction motor drives the vehicle alone;

[0029] (3) Series driving charging mode: When the vehicle's traction demand power P is less than the maximum output power P of the traction motor 牵引max , the required torque T is less than the maximum output torque T of the traction motor 牵引max When the power battery is lower than the preset minimum power threshold SOC min , then the diesel engine, motor, and traction motor are turned on, and the diesel engine output power P 油 All drive motors generate electricity, which charges the power battery and supplies power to the traction motor, which drives the vehicle alone.

[0030] (4) Parallel joint drive mode: When the vehicle is in a state where the traction demand power P is greater than the maximum output power P of the traction motor 牵引max , the required torque T is greater than the maximum output torque T of the traction motor 牵引max When the traction demand power is greater than the diesel engine output power P 油 , the diesel engine and traction motor are turned on, the motor is turned off, and the diesel engine and traction motor jointly drive the vehicle to work;

[0031] (5) Parallel driving charging mode: When the vehicle's traction demand power P is less than the diesel engine output power P 油 , the required torque T is less than the maximum output torque T of the traction motor 牵引max When the power battery is lower than the preset minimum power threshold SOC min , the diesel engine and the motor are turned on, and the traction motor is turned off. The power output by the diesel engine is divided into two parts. One part is output to the motor. The electric energy generated by the motor is used to charge the power battery. The other part is input to the planetary gear. That is, the diesel engine drives the vehicle alone and charges the power battery through the motor at the same time.

[0032] (6) Hybrid joint drive mode: When the vehicle's traction demand power P is greater than the diesel engine output power P 油 and the maximum output power of the traction motor P 牵引max The sum of the required torque T is greater than the diesel engine output torque T 油 and the maximum output torque of the traction motor T 牵引maxWhen the working condition is equal to the sum of the above, the diesel engine, motor and traction motor are turned on, the motor is used as a motor, and the diesel engine, motor and traction motor jointly drive the vehicle to work;

[0033] (7) Deceleration / Braking Energy Recovery Mode: When the vehicle is in a deceleration or braking condition, the diesel engine and traction motor are shut down and the motor is used as a generator to recover the energy generated during the deceleration or braking process.

[0034] See also Figure 2 , this tractor provides two driving modes: intelligent driving and manual driving when performing field operations. In relatively regular field conditions with few obstacles, after the driver selects the intelligent driving mode, the industrial control machine will judge whether the current working environment meets the conditions for intelligent driving. The perception information module is used to collect the current working environment information. If the working environment information meets the conditions for intelligent driving, the intelligent driving mode is started; if the working environment information does not meet the conditions for intelligent driving, the intelligent driving mode is not started and the driving mode setting is returned. When the intelligent driving mode is started, the starting point and the end point are set, and the tractor can operate in the field according to the preset path. The perception information module includes a laser radar, a binocular camera, and a gyroscope. The laser radar and the binocular camera are responsible for collecting the driving environment information required by the intelligent driving tractor, providing a reliable decision-making basis for the safe driving of the intelligent driving tractor; the gyroscope is responsible for collecting the state information of the tractor body in the posture space to ensure that the intelligent driving tractor can operate continuously and stably. The speed sensor is responsible for collecting the travel speed information of the intelligent driving tractor to ensure that the driving speed of the tractor is reasonable. The vehicle controller collects real-time information about the whole machine operation (including working condition information obtained by the industrial computer, vehicle speed information fed back by the speed sensor, and power battery SOC value) through CAN bus and UDP communication, and performs data processing and analysis, and coordinates and reasonably controls the power transmission system (traction motor, motor, clutch, diesel engine, steering power pump) and intelligent driving perception system of the intelligent driving tractor to ensure that the intelligent driving tractor operates according to the preset requirements. After the operation requirements are met, the intelligent driving operation ends; if the operation requirements are not met, the perception information module continues to collect the operating environment information. When the collected operating environment information still meets the intelligent driving conditions, the tractor continues to operate the intelligent driving mode until the operation requirements are met. After the tractor completes the operation in the intelligent driving mode, the intelligent driving operation of this tractor ends, returns to the setting of the driving mode, and the driver takes over the operation of the tractor.

[0035] In field conditions with bad weather, poor recognition effect of the intelligent driving perception system, or complex, rugged, and many obstacles on the field road, when the environmental information collected by the perception information module cannot meet the conditions of the intelligent driving mode, it can be switched to manual driving mode, which is similar to the general parallel-parallel hybrid tractor.

[0036] The above shows and describes the main features, basic principles and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements according to actual conditions, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. Intelligent driving series-parallel hybrid tractor topology, characterized by It includes a power transmission system and an intelligent driving perception system. The power transmission system includes a power battery, an AC / DC module, a DC / DC module, a diesel engine, a motor, a traction motor, a planetary gear, a clutch, a transmission, a power steering pump, a PTO assembly, a central transmission device, and a vehicle controller. The diesel engine and the motor are matched. The motor adopts a through-shaft motor and is coupled with the diesel engine for torque. The motor is coupled with the output power of the planetary gear and the traction motor through the clutch and then transmitted to the transmission. The power output end of the transmission is mechanically connected with the power steering pump, the PTO assembly, and the central transmission device installed on the rear wheel axle; The intelligent driving perception system includes a low-voltage battery, an industrial computer, a speed sensor, a gyroscope, a laser radar and a binocular camera. The power battery is electrically connected to the low-voltage battery through a DC / DC module, and the power battery is connected to the traction motor and the motor through an AC / DC module; the low-voltage battery is electrically connected to the laser radar, binocular camera, speed sensor, gyroscope, vehicle controller and industrial computer respectively; the laser radar is connected to the industrial computer through Ethernet, the binocular camera is connected to the industrial computer through a CAN bus, and the speed sensor is used to collect the travel speed of the tractor; the vehicle controller is connected to the power battery, low-voltage battery, gyroscope, speed sensor, diesel engine, clutch, power steering pump, traction motor, motor, PTO assembly, transmission, AC / DC module and DC / DC module through a CAN bus respectively; the vehicle controller also communicates data with the industrial computer through UDP communication to obtain the working condition information of the tractor from the industrial computer.

2. The topology of the intelligent driving series-parallel hybrid tractor according to claim 1 is characterized by: When a hybrid tractor with the topological structure is used for field operations, an intelligent driving mode and a manual driving mode are provided. If the driver selects the manual driving mode, the driver manually controls the tractor to perform the operation. If the driver selects the intelligent driving mode, the industrial control machine will judge whether the current working environment meets the conditions for intelligent driving. The perception information module is used to collect the current working environment information. If the working environment information meets the conditions for intelligent driving, the intelligent driving mode is started. If the working environment information does not meet the conditions for intelligent driving, the intelligent driving mode is not started and the driving mode setting is returned to. The perception information module includes a laser radar for detecting the distance between the tractor body and the obstacle, a binocular camera for collecting information on objects on the tractor body's route, and a gyroscope for collecting angle signals of the tractor body in a multi-degree-of-freedom space.

3. Intelligent driving hybrid tractor operation mode, characterized by After the diesel engine is turned on, it is always operating in the high efficiency zone, and the output power of the diesel engine is P 油 , the output torque is T 油 ; The maximum output power of the traction motor is P 牵引max , the maximum output torque is T 牵引max ; Preset maximum power threshold SOC max The SOC value is 80% of the full charge state, and the preset minimum power threshold SOC min The SOC value is 30% of the fully charged state, and the hybrid tractor adopting the topological structure described in claim 1 or 2 has the following basic operating modes: (1) Traction motor drive mode: When the vehicle's traction demand power P is less than the maximum output power P of the traction motor 牵引max , the required torque T is less than the maximum output torque T of the traction motor 牵引max When the power battery is higher than the preset maximum power threshold SOC max , the diesel engine and the electric motor are turned off, the traction motor is turned on, and the traction motor drives the vehicle alone; (2) Series combined drive mode: When the vehicle is in a state where the traction demand power P is less than the maximum output power P of the traction motor 牵引max , the required torque T is less than the maximum output torque T of the traction motor 牵引max When the power battery is higher than the preset minimum power threshold SOC min , then the diesel engine, motor, and traction motor are turned on, the diesel engine drives the motor to generate electricity, the motor and the power battery jointly supply power to the traction motor, and the traction motor drives the vehicle alone; (3) Series driving charging mode: When the vehicle's traction demand power P is less than the maximum output power P of the traction motor 牵引max , the required torque T is less than the maximum output torque T of the traction motor 牵引max When the power battery is lower than the preset minimum power threshold SOC min , then the diesel engine, motor, and traction motor are turned on, and the diesel engine output power P 油 All drive motors generate electricity, which charges the power battery and supplies power to the traction motor, which drives the vehicle alone. (4) Parallel joint drive mode: When the vehicle is in a state where the traction demand power P is greater than the maximum output power P of the traction motor 牵引max , the required torque T is greater than the maximum output torque T of the traction motor 牵引max When the traction demand power is greater than the diesel engine output power P 油 , the diesel engine and traction motor are turned on, the motor is turned off, and the diesel engine and traction motor jointly drive the vehicle to work; (5) Parallel driving charging mode: When the vehicle's traction demand power P is less than the diesel engine output power P 油 , the required torque T is less than the maximum output torque T of the traction motor 牵引max When the power battery is lower than the preset minimum power threshold SOC min , the diesel engine and the motor are turned on, the traction motor is turned off, and the diesel engine drives the vehicle alone while charging the power battery through the motor; (6) Hybrid joint drive mode: When the vehicle's traction demand power P is greater than the diesel engine output power P 油 and the maximum output power of the traction motor P 牵引max The sum of the required torque T is greater than the diesel engine output torque T 油 and the maximum output torque of the traction motor T 牵引max When the working condition is equal to the sum of the above, the diesel engine, motor and traction motor are turned on, the motor is used as a motor, and the diesel engine, motor and traction motor jointly drive the vehicle to work; (7) Deceleration / Braking Energy Recovery Mode: When the vehicle is in a deceleration or braking condition, the diesel engine and traction motor are shut down and the motor is used as a generator to recover the energy generated during the deceleration or braking process.

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