Hybrid tractor power system, control method, product, equipment and medium

Abstract

The invention provides a hybrid power tractor power system, a control method, a product, equipment and a medium, and relates to the technical field of tractors. The CVT gearbox adopts a structure of double power batteries, double driving motors and double variable motors, the double power batteries comprise a first power battery and a second power battery, the double driving motors comprise a first driving motor and a second driving motor, and the double variable motors comprise a generator and a CPTO driving motor; the tractor provides three types of power paths: an engine directly provides power for wheels through a gear pair; the engine drives the generator to charge the dual-power battery, and the dual-power battery is connected with at least any one of the dual-drive motor and the dual-variable motor to provide power for the wheels; the engine drives the generator to charge the dual-power battery, and the dual-power battery drives the motor to provide power for the agricultural implement through the CPTO. The overall performance and the operation efficiency of the tractor are remarkably improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of tractors, and in particular to a hybrid tractor power system, control method, product, equipment and medium. Background Art

[0002] With the acceleration of the global agricultural modernization process, tractors, as the core power equipment in agricultural production, are increasingly concerned about their energy efficiency and environmental impact. Traditional tractors mostly rely on diesel engines. Although they have strong power output, they also face problems such as high fuel consumption and heavy emissions. Especially in complex operating environments, the load of the tractor's power system fluctuates greatly, causing the engine to often be in non-optimal working conditions, further exacerbating fuel waste and environmental pollution. Therefore, how to improve the energy efficiency of tractors and reduce emissions has become a problem that needs to be solved urgently in the current agricultural machinery field.

[0003] In this context, hybrid tractors, as an emerging power system solution, have gradually attracted research and application attention. By combining the advantages of traditional internal combustion engines and electric motors, hybrid technology can not only optimize power output under different working conditions and improve energy efficiency, but also effectively reduce emissions and reduce environmental burdens; especially during operation, the hybrid system can dynamically adjust the power source according to load demand, thereby avoiding the internal combustion engine running in an inefficient working condition for a long time, improving the overall efficiency of the system and the operating performance of the tractor.

[0004] With the continuous development of battery technology and control strategies, hybrid tractors are not only expected to make breakthroughs in energy efficiency and emissions, but also provide new possibilities for the green transformation of agricultural machinery. There are currently two main technical routes for hybrid tractors: plug-in hybrid electric vehicle (PHEV) and range-extended hybrid electric vehicle (REEV). The engine and generator in the plug-in hybrid electric vehicle (PHEV) can work together to support both motor drive and engine drive. The engine of the range-extended hybrid electric vehicle (REEV) does not directly drive the wheels, but acts as a generator to charge the battery, and the vehicle is completely driven by the motor.

[0005] Faced with the complex and ever-changing farmland operation environment, the plug-in hybrid transmission can improve fuel economy under low-load conditions with its larger battery capacity and longer electric endurance. The extended-range hybrid transmission uses its efficient energy management system to enable the engine to operate under optimal conditions, taking into account both power and fuel economy, and is particularly suitable for long-term, high-load operation scenarios. At the same time, there are some technical problems with the two different routes of hybrid tractors: 1. Plug-in hybrid tractors have problems (1) When plug-in hybrid tractors rely on batteries for pure electric drive, the battery capacity is limited, which means that during long-term high-load operations, the battery power may be quickly consumed, affecting operation time and efficiency, especially in rural areas where there is a lack of charging facilities, which may cause operation interruptions.

[0006] (2) To meet their charging needs, plug-in hybrid tractors require a complete charging infrastructure. Although charging is relatively easy in cities or more developed areas, in remote rural areas, the lack of charging facilities will limit their use.

[0007] (3) Batteries are key components of plug-in hybrid systems and are usually expensive. As they are used, the characteristics of the batteries change, their healthy lifespan decreases, and the cost of replacing them is relatively high. In addition, batteries may perform poorly in low-temperature environments, affecting operating efficiency in low-temperature seasons.

[0008] To sum up, plug-in hybrid tractors are designed to rely mainly on batteries for pure electric drive, and their working scenarios are mostly suitable for modern small farms that can be charged in time; similarly, the heavier the tractor, the faster the electricity is consumed, which limits the weight of the tractor itself and the mounted agricultural machinery.

[0009] 2. Problems with extended-range hybrid tractors (1) The engine in the extended-range hybrid system usually needs to operate under specific operating conditions (such as optimal speed). However, under some low-load or high-load conditions, the engine may not operate within its optimal efficiency range, resulting in reduced fuel economy.

[0010] (2) As a key component of the extended-range tractor, the battery can provide electric drive for a short period of time, but the battery capacity is limited and cannot support long-term high-load operation. The battery life will also gradually decrease with the increase in the number of charge and discharge cycles.

[0011] Therefore, existing hybrid tractors have deficiencies in economy, overall performance and operating efficiency. Summary of the invention

[0012] In order to solve the above problems, the present disclosure proposes a hybrid tractor power system, control method, product, equipment and medium, which significantly improve the overall performance and operating efficiency of the tractor.

[0013] According to some embodiments, the present disclosure adopts the following technical solutions: A hybrid tractor power system includes an engine and a CVT transmission; The CVT gearbox adopts a structure of dual power batteries, dual drive motors, and dual variable motors. The dual power batteries include a first power battery and a second power battery. The dual drive motors include a first drive motor and a second drive motor. The dual variable motors include a generator and a CPTO drive motor. The tractor provides three types of power paths: First power path: the engine directly provides power to the wheels through a gear pair; Second power path: the engine drives the generator to charge the dual power battery, and the dual power battery is connected to at least any motor of the dual drive motor and the dual variable motor to provide power for the wheels; The third power path: the engine drives the generator to charge the dual power batteries, and the dual power batteries drive the motor through the CPTO to provide power for the agricultural machinery.

[0014] According to some embodiments, the present disclosure adopts the following technical solutions: A control method for a hybrid tractor power system selects a power path for control according to the current working mode of the tractor, specifically: In the low-load starting mode, the second power path is selected, and the first drive motor and the second drive motor are driven jointly; In the high-load starting mode, the second power path is selected. Under the premise that the first drive motor and the second drive motor are driven together, it is determined whether the generator and the CPTO drive motor participate in the driving according to the required power. In the low-load walking mode, the second power path is selected, and the first drive motor and the second drive motor are driven jointly; In high-load walking mode, there are two control modes according to the discharge rate of the power battery: (1) When at least one of the discharge rates of the first power battery and the second power battery is greater than a threshold, a combination of the first power path and the second power path is selected, and under the premise of joint driving of the engine and the second drive motor, whether the CPTO drive motor participates in the driving is determined based on the required power; (2) When the discharge rates of the first power battery and the second power battery are not greater than the threshold, the second power path is selected. Under the premise that the first drive motor and the second drive motor are jointly driven, it is determined whether the generator and the CPTO drive motor participate in the driving according to the required power; In the current working mode, when there is a need for farming, a third power path is added for combined control; Among them, in the control process when the generator is not converted into a drive motor, the charging and discharging of the first power battery and the second power battery are differentially controlled according to the real-time predicted low resistance interval and the current battery power.

[0015] According to some embodiments, the present disclosure adopts the following technical solutions: A computer program product comprises a computer program, wherein when the computer program is executed by a processor, the control method of a hybrid power tractor power system is implemented.

[0016] According to some embodiments, the present disclosure adopts the following technical solutions: A non-transitory computer-readable storage medium is used to store computer instructions. When the computer instructions are executed by a processor, a control method for a hybrid tractor power system is implemented.

[0017] According to some embodiments, the present disclosure adopts the following technical solutions: An electronic device comprises: a processor, a memory and a computer program; wherein the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device is running, the processor executes the computer program stored in the memory, so that the electronic device executes the control method for implementing the hybrid tractor power system.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (I) In response to the plug-in hybrid problem, the present invention adopts an extended-range hybrid technology solution, which provides continuous power to the first power battery and the second power battery through the engine-driven generator, thereby significantly improving the effective mileage of the tractor in a single operation.

[0019] (ii) To address the problem of excessive power consumption under heavy load conditions, in addition to adopting the extended-range hybrid technology solution, the present invention introduces the idea of ​​connecting the engine and the drive motor in parallel into the drive path. Through the engagement of the first clutch and the third clutch, the engine directly participates in the drive. In this case, the engine can not only drive the generator, but also drive the gear pair.

[0020] (III) By optimizing the starting process of the tractor, the present invention effectively solves the power problem under low load and high load conditions; when starting under low load, it avoids excessive consumption of battery power caused by multi-motor drive, thereby improving the economy of the whole machine; and when starting under high load, by reasonably configuring the power system, it avoids the problem of insufficient power of a single motor drive, ensuring the stability and efficiency of the tractor's starting; these improvement measures significantly improve the overall performance and operating efficiency of the tractor.

[0021] (IV) In order to address the battery life issue of extended-range hybrid tractor power batteries and taking into account the life attenuation laws of multiple power batteries, the present invention proposes a multi-battery output power dynamic balancing method based on the battery low resistance power range; this method can dynamically adjust the charging and discharging strategy according to the health status of the battery, so that the energy consumption of the tractor is always maintained within the optimal energy efficiency range, extending the battery life, while improving the overall economy and reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings constituting a part of the present disclosure are used to provide a further understanding of the present disclosure. The illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation on the present disclosure.

[0023] Figure 1 This is a structural diagram of the hybrid tractor power system of Example 1.

[0024] Figure 2 Graph showing the relationship between the battery internal resistance and the battery capacity (SOC) of Example 2.

[0025] Among them, 1. engine; 2. generator; 3. first drive motor; 4. first power battery; 5. second power battery; 6. second drive motor; 7. first gear pair; 8. second gear pair; 9. first clutch; 10. third gear pair; 11. fourth gear pair; 12. planetary gear ring; 13. planetary gear carrier; 14. planetary gear sun gear; 15. fifth gear pair; 16. sixth gear pair; 17. seventh gear pair; 18. eighth gear pair; 19. ninth gear pair; 20. tenth gear pair; 21. eleventh gear pair; 22. CPTO drive motor; 23. CPTO clutch; 24. second clutch; 25. twelfth gear pair; 26. thirteenth gear pair; 27. third clutch; 28. planetary gear mechanism; 29. ​​CVT gearbox; S1. first control switch; S2. second control switch; S3. third control switch; S4. fourth control switch; S5. fifth control switch; S6. sixth control switch; S7. seventh control switch; S8, the eighth control switch. DETAILED DESCRIPTION

[0026] The present disclosure is further described below in conjunction with the accompanying drawings and embodiments.

[0027] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present disclosure. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present disclosure belongs.

[0028] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0029] Terminology explanation: CPTO: Clutch Power Take Off power output device clutch; CVT: Continuously Variable Transmission) continuously variable speed change.

[0030] Example 1 In one embodiment of the present disclosure, a hybrid tractor power system is provided, such as Figure 1 As shown, it includes an engine 1 and a CVT gearbox 29, Figure 1 The red line in the middle is the harness connection, the black line is the mechanical connection, and the blue line is the shaft connection; The CVT gearbox 29 adopts a structure of dual power batteries, dual drive motors, and dual variable motors. The dual power batteries include a first power battery 4 and a second power battery 5. The dual drive motors include a first drive motor 3 and a second drive motor 6. The dual variable motors include a generator 2 and a CPTO drive motor 22.

[0031] The tractor provides three types of power paths: First power path: the engine 1 directly provides power to the wheels through a gear pair; Specifically, the driving path of the engine 1 is: the engine 1 drives the first gear pair 7, the first gear pair 7 drives the second gear pair 8 to rotate, and the second gear pair 8 drives the planetary gear ring 12. When the power is transmitted to the planetary gear ring 12, a power path for the engine 1 to transmit power to the planetary gear mechanism 28 is realized here. Under this power path, the engine 1 directly participates in the working process of providing power to the wheels.

[0032] Second power path: the engine 1 drives the generator 2 to charge the dual power battery, and the dual power battery is connected to at least any motor of the dual drive motor and the dual variable motor to provide power for the wheels; Among them, the driving path of the first driving motor 3 is: the first driving motor 3 drives the third gear pair 10, drives the third gear pair 10 to rotate, the third gear pair 10 drives the fourth gear pair 11, the fourth gear pair 11 drives the planetary gear ring 12 to rotate, and transmits power to the planetary gear mechanism 28.

[0033] The driving path of the second driving motor 6 is: the second driving motor 6 drives the fifth gear pair 15 , and the fifth gear pair 15 drives the sixth gear pair 16 to transmit power to the planetary gear mechanism 28 .

[0034] The driving path (driving wheels) of the CPTO drive motor 22 is: the CPTO drive motor 22 drives the twelfth gear pair 25, the twelfth gear pair 25 drives the thirteenth gear pair 26, the thirteenth gear pair 26 drives the fifth gear pair 15, the fifth gear pair 15 drives the sixth gear pair 16, and transmits power to the planetary gear mechanism 28.

[0035] The third power path: the engine 1 drives the generator 2 to charge the dual power battery, and the dual power battery drives the motor 22 through the CPTO to provide power for the agricultural machinery.

[0036] Specifically, the driving path (driving the agricultural implement) of the CPTO driving motor 22 is as follows: the CPTO driving motor 22 is connected to the agricultural implement through the CPTO clutch 23 to provide power for the agricultural implement.

[0037] The wheels have a reverse gear and a forward gear. The ninth gear pair 19, the tenth gear pair 20, and the eleventh gear pair 21 are all used for the reverse gear, while the eighth gear pair 18 is used for the forward gear.

[0038] When the power is gathered in the planetary gear mechanism 28, the planetary gear carrier 13 serves as the output end of the power. The planetary gear carrier 13 drives the seventh gear pair 17. The seventh gear pair 17 drives different gear pairs to output power according to the reverse gear or the forward gear.

[0039] Furthermore, the engine 1 is connected to the generator 2 through the third clutch 27, the engine 1 is connected to the wheels through the first gear pair 7, the second gear pair 8, the first clutch 9, and the planetary gear mechanism 28, and the generator 2 is connected to the first power battery 4 and the second power battery 5 through the first control switch S1 and the second control switch S2, respectively.

[0040] Further, the outputs of the first power battery 4 and the second power battery 5 are connected to the first drive motor 3 through the third control switch S3 and the fourth control switch S4, respectively, connected to the second drive motor 6 through the fifth control switch S5 and the sixth control switch S6, respectively, and connected to the CPTO drive motor 22 through the seventh control switch S7 and the eighth control switch S8; Furthermore, the first drive motor 3 and the second drive motor 6 are connected to the wheels through a gear pair and a planetary gear mechanism 28 respectively; Furthermore, the CPTO drive motor 22 is connected to the agricultural implement via the CPTO clutch 23 , and is connected to the wheels via a gear pair, a second clutch 24 , and a planetary gear mechanism 28 .

[0041] The battery capacity of the plug-in hybrid mode is limited. At the same time, the tractor working mode preset by the plug-in hybrid is mainly the pure electric mode. The battery capacity plays a decisive role in the tractor's endurance and power. Therefore, this mode is not suitable for medium and large tractors used in large farms. Therefore, this embodiment adopts a new hybrid tractor with dual power batteries + dual drive motors + dual variable motors. By controlling the clutch and the switch, the speed regulation process of variable load is realized, making the entire power system more reliable and easy to maintain later. The key points of the new hybrid tractor are described below: 1. The engine 1 drives the generator 2 to generate electricity to continuously provide power to the first power battery 4 and the second power battery 5, so as to achieve the purpose of driving charging, specifically: When the power level of either the first power battery 4 or the second power battery 5 drops to the lower limit of the predicted battery low resistance power range, the driving charging mode is turned on, and the first control switch S1 of the generator 2 and the second control switch S2 of the generator 2 are closed.

[0042] By engaging the third clutch 27, the engine 1 drives the generator 2 to generate electricity, and charges the first power battery 4 and the second power battery 5 while driving. When the power levels of the two power batteries reach the upper limit of the predicted low resistance power range of the battery, the first control switch S1 and the second control switch S2 are disconnected, and the driving charging mode is turned off.

[0043] 2. In order to solve the problem of excessive battery discharge rate caused by heavy load or cold environment during walking, the idea of ​​parallel connection of engine 1 and drive motor is introduced into the driving path. Through the engagement of the first clutch 9 and the third clutch 27, the engine 1 directly participates in the operation of the CVT gearbox 29, drives the first gear pair 7, and provides power for the tractor.

[0044] The battery discharge rate is too fast. In this embodiment, it is defined as a discharge rate of not less than 0.5C. A discharge rate of 0.5C means that the battery is fully discharged within 2 hours. If the capacity of the battery is 100Ah, it is discharged at a current of 100A within 2 hours. A discharge rate of 1C means that the battery is fully discharged within 1 hour. If the capacity of the battery is 100Ah, it is discharged at a current of 100A within 1 hour.

[0045] The idea of ​​parallel connection of engine 1 and drive motor is introduced into the drive path. The specific implementation method is as follows: Through the engagement of the first clutch 9 and the third clutch 27, the engine 1 participates in driving the first gear pair 7, and transmits power to the second gear pair 8 through the first gear pair 7. At the same time, the third control switch S3 and the fourth control switch S4 are disconnected, the first drive motor 3 stops working, the fifth control switch S5 and the sixth control switch S6 are closed, and the dual power battery supplies power to the second drive motor 6, thereby realizing a power transmission path in which the engine 1 and the second drive motor 6 transmit power to the planetary gear ring 12 of the planetary gear mechanism 28, and the planetary gear carrier 13 outputs power.

[0046] By adopting the power transmission mode of connecting the engine 1 and the second drive motor 6 in parallel, the pure electric mode is changed to the parallel hybrid mode, which can effectively alleviate the problem of excessive power consumption of the power battery. At the same time, according to the following formula (1), the required torque of the planetary gear carrier 13 is greater. In this connection mode, the engine 1 can directly gather power to the planetary gear carrier 13: (1) Wherein, M14 is the torque of the planetary gear sun gear 14 , M12 is the torque of the planetary gear ring gear 12 , M13 is the torque of the planetary gear carrier 13 , and α is the gear ratio between the planetary gear ring gear 12 and the planetary gear sun gear 14 .

[0047] 3. During the starting process of the tractor, there will be many different operating conditions, and the loads on the tractor are different in different conditions. In the case of low-load starting, multi-motor drive will increase the power consumption of the power battery and reduce the economy of the whole machine. In the case of high-load starting, the power shortage caused by a single motor drive will make it difficult to start the tractor and reduce efficiency. At the multiple input ends of the planetary gear, if the required torque at the input end is greater than the rated torque of the single motor, it is considered to be high load, otherwise it is low load. The specific solutions are: For low-load starting conditions, a higher power supply can be guaranteed through the combination of multiple power batteries.

[0048] Specifically, under low load conditions, the first drive motor 3 and the second drive motor 6 are dual-motor driven to transmit power to the planetary gear mechanism 28, and the planetary gear carrier 13 transmits power outward to drive the wheels.

[0049] In the case of high-load starting, the tractor is subject to greater static friction from the ground, and stronger power is required.

[0050] At this time, the first clutch 9 and the second clutch 24 are both engaged, the third clutch 27 is disconnected, the engine 1 is not working, and the tractor is in pure electric mode. The pure electric mode starting has higher mechanical efficiency than the engine 1 and the drive motor in parallel. The first control switch S1 and the second control switch S2 are closed, the first power battery 4 and the second power battery 5 supply power to the generator 2, and the generator 2 acts as a drive motor to provide power to the first and seventh gear pairs 17. The generator 2, the first drive motor 3, the second drive motor 6, and the CPTO drive motor 22 are driven simultaneously to transmit power to the planetary mechanism, and the planetary gear planet carrier 13 transmits power outward to drive the wheels.

[0051] Example 2 In one embodiment of the present disclosure, a control method for a hybrid tractor power system is provided. According to the current working mode of the tractor, a power path is selected for control, that is, according to different loads, the number of motors involved in driving the power system is different. The power system adopts a "dual power battery + dual drive motor + dual variable motor" structure to realize dual motor or four motor drive. At the same time, the prediction of the internal resistance of multiple power batteries realizes the dynamic balance of multi-battery charging and discharging, and realizes the separate control of the state of the generator 2, the state of the drive motor, the state of the control switch, the state of the drive clutch and the state of the CPTO clutch 23. The control methods of several typical working modes of the tractor are given below: 1. Low load start mode Select the second power path, the first drive motor 3 and the second drive motor 6 are driven jointly, and the current state is: 1) The state of generator 2: determined by SOC, that is, whether the power SOC is less than the lower limit SOC of the low resistance range min_limit , if it is less than, then electricity is generated; 2) Driving motor state: the first driving motor 3 and the second driving motor 6 are driven jointly; 3) Control switch state: the seventh control switch S7 and the eighth control switch S8 are disconnected, the third control switch S3, the fourth control switch S4, the fifth control switch S5, and the sixth control switch S6 are closed, and the first control switch S1 and the second control switch S2 are determined according to the SOC; 4) Driving clutch state: The third clutch 27 is determined according to the SOC; 5) CPTO clutch 23 status: engagement or disengagement is determined based on whether farming is in progress.

[0052] 2. High load starting mode Select the second power path. Under the premise that the first drive motor 3 and the second drive motor 6 are jointly driven, determine whether the generator 2 and the CPTO drive motor 22 participate in the drive according to the required power. The current state is: 1) Status of generator 2: No power generation 2) Driving motor state: the generator 2 is converted into a driving motor, and the generator 2, the first driving motor 3, the second driving motor 6, and the CPTO driving motor 22 are driven; 3) Control switch status: the first control switch S1, the second control switch S2, the seventh control switch S7, and the eighth control switch S8 are closed, and the third control switch S3, the fourth control switch S4, the fifth control switch S5, and the sixth control switch S6 are closed; 4) Driving clutch state: the first clutch 9 and the second clutch 24 are engaged, and the third clutch 27 is determined according to the SOC; 5) CPTO clutch 23 status: engagement or disengagement is determined based on whether farming is in progress.

[0053] Here, in the case of "no need to perform farming" and "no need to generate electricity", the generator 2 is converted into a drive motor and the CPTO drive motor 22 drives whether to provide power as a drive motor, and the judgment conditions are: If the required torque of the fifth gear pair 15 is greater than the rated torque of the second drive motor 6, the CPTO drive motor 22 participates in the drive; if the required torque of the third gear pair 10 is greater than the rated torque of the first drive motor 3, driving and charging are not possible, and the generator 2 is used as the drive motor.

[0054] 3. Low load walking mode Select the second power path, the first drive motor 3 and the second drive motor 6 are driven jointly, and the current state is: 1) The state of generator 2: determined by SOC, that is, whether the power SOC is less than the lower limit SOC of the low resistance range min_limit , if it is less than, then electricity is generated; 2) Driving motor status: the first driving motor 3 and the second driving motor 6 are driving; 3) Control switch state: the seventh control switch S7 and the eighth control switch S8 are disconnected, the third control switch S3, the fourth control switch S4, the fifth control switch S5, and the sixth control switch S6 are closed, and the first control switch S1 and the second control switch S2 are determined according to the SOC; 4) Driving clutch state: The third clutch 27 is determined according to the SOC; 5) CPTO clutch 23 status: engagement or disengagement is determined based on whether farming is in progress.

[0055] 4. High load walking mode According to the discharge rate of the power battery, there are two control methods: The first control mode: when at least one of the discharge rates of the first power battery 4 and the second power battery 5 is greater than a threshold, a combination of the first power path and the second power path is selected. Under the premise of joint driving of the engine 1 and the second drive motor 6, it is determined whether the CPTO drive motor 22 participates in the driving according to the required power, and two high-load walking modes are provided: (1) High-load walking mode 1, the condition is that the battery discharge rate>0.5C&&the required torque of the fifth gear pair 15<the rated torque of the second drive motor 6: 1) The state of generator 2: determined by SOC, that is, whether the power SOC is less than the lower limit SOC of the low resistance range min_limit , if it is less than, then electricity is generated; 2) Driving motor state: the second driving motor 6 is driven; 3) Control switch status: the fifth control switch S5 and the sixth control switch S6 are closed, the first control switch S1 and the second control switch S2 are determined according to the SOC, and the third control switch S3, the fourth control switch S4, the seventh control switch S7, and the eighth control switch S8 are opened; 4) Driving clutch state: the first clutch 9 and the third clutch 27 are engaged, and the second clutch 24 is disengaged; 5) CPTO clutch 23 status: engagement or disengagement is determined based on whether farming is in progress.

[0056] (2) High-load walking mode 2, the condition is that the battery discharge rate>0.5C&&the required torque of the fifth gear pair 15>the rated torque of the second drive motor 6: 1) The state of generator 2: determined by SOC, that is, whether the power SOC is less than the lower limit SOC of the low resistance range min_limit , if it is less than, then electricity is generated; 2) Driving motor status: the second driving motor 6 and the CPTO driving motor 22 are driven; 3) Control switch status: the fifth control switch S5, the sixth control switch S6, the seventh control switch S7, and the eighth control switch S8 are closed, the first control switch S1 and the second control switch S2 are determined according to the SOC, and the third control switch S3 and the fourth control switch S4 are opened; 4) Driving clutch state: the first clutch 9, the second clutch 24, and the third clutch 27 are engaged; 5) CPTO clutch 23 status: engagement or disengagement is determined based on whether farming is in progress.

[0057] The second control mode: when the discharge rate of the first power battery 4 and the second power battery 5 is not greater than the threshold, the second power path is selected. Under the premise of the joint driving of the first drive motor 3 and the second drive motor 6, it is determined whether the generator 2 and the CPTO drive motor 22 participate in the driving according to the required power, and two high-load walking modes are provided: (1) High-load walking mode 3, the condition is that the battery discharge rate is <0.5C && the required torque of the fifth gear pair 15 is < the rated torque of the second drive motor 6: 1) The state of generator 2: determined by SOC, that is, whether the power SOC is less than the lower limit SOC of the low resistance range min_limit , if it is less than, then electricity is generated; 2) Driving motor status: first driving motor 3, second driving motor 6; 3) Control switch state: the third control switch S3, the fourth control switch S4, the fifth control switch S5, the sixth control switch S6, the seventh control switch S7, and the eighth control switch S8 are closed, and the first control switch S1 and the second control switch S2 are determined according to the SOC; 4) Driving clutch state: the second clutch 24 is engaged, and the third clutch 27 is determined according to the SOC; 5) CPTO clutch 23 status: engagement or disengagement is determined based on whether farming is in progress.

[0058] (2) High-load walking mode 4, the condition is that the battery discharge rate <0.5C && the required torque of the fifth gear pair 15 > the rated torque of the second drive motor 6: 1) The state of generator 2: determined by SOC, that is, whether the power SOC is less than the lower limit SOC of the low resistance range min_limit , if it is less than, then electricity is generated; 2) Driving motor status: the first driving motor 3, the second driving motor 6, and the CPTO driving motor 22 are driven; 3) Control switch state: the third control switch S3, the fourth control switch S4, the fifth control switch S5, the sixth control switch S6, the seventh control switch S7, and the eighth control switch S8 are closed, and the first control switch S1 and the second control switch S2 are determined according to the SOC; 4) Driving clutch state: the second clutch 24 is engaged, and the third clutch 27 is determined according to the SOC; 5) CPTO clutch 23 status: engagement or disengagement is determined based on whether farming is in progress.

[0059] In the current working mode, when there is a demand for farming, that is, farming needs to be carried out, a third power path is added for combined control.

[0060] In the control process when the generator 2 is not converted into a driving motor, the charging and discharging of the first power battery 4 and the second power battery 5 are differentially controlled according to the real-time predicted low resistance interval and the current battery power.

[0061] The following is a detailed description of the differentiated control: The quality of power batteries is mainly considered from the aspects of energy storage density, energy release capacity per unit time, battery safety life and whether it is environmentally friendly. At present, lithium batteries are often used as the power source of new energy vehicles in China, and their performance in the above aspects is much better than traditional chemical batteries. The battery selection of extended-range buses is considered from the aspects of service life and battery stability. Lithium iron phosphate batteries, which are better than ternary lithium batteries, are used as the type of power batteries. Because power batteries are composed of many single cells with small rated voltage and capacity through series and parallel connection.

[0062] The parameters of each single cell are not exactly the same during manufacturing. As the number of uses increases, the battery parameters continue to change. The most obvious manifestation is that the battery internal resistance will continue to change with SOC.

[0063] The internal resistance trend of lithium iron phosphate battery during use is as follows Figure 2 As shown in the figure, when discharging at 100~60% and 30%~0, the internal resistance continues to increase and the consumed electric power continues to increase; when the SOC is in the range of 30~60%, the resistance value is low and the change is gentle; therefore, the SOC of 30~60% is defined as the optimal energy consumption range of the battery, and the subsequent control rules and SOC charging threshold value also refer to this relationship.

[0064] At the same time, the optimal energy consumption range is not fixed. It will change with the use and aging of the battery. In particular, the increase in internal resistance may cause the original optimal energy consumption range to shrink or change. The battery temperature, usage environment, charging method, and optimization of the battery management system will affect the range and performance of the optimal energy consumption range.

[0065] During battery use, the increase in internal resistance and the attenuation of capacity are inevitable. Reasonable charging and usage strategies can help delay changes in the optimal energy consumption range and optimize the overall performance of the battery.

[0066] Therefore, this embodiment uses the LSTM+ reinforcement learning method for real-time prediction. Before training the prediction model, the data must first be collected and processed, including SOC, internal resistance, current, voltage, temperature, C-rate (charge and discharge rate), and number of cycles; the time step Δt (1min) is set, and the data shown in Table 1 is collected and input into the data set. As shown in formula (2), the output data set As shown in formula (3): (2) (3) Among them, SOC 1min_limit is the lower limit of the low resistance range predicted by the first power battery 4; SOC 1max_limit The upper limit of the low resistance range predicted for the first power battery 4; SOC 2min_limit The lower limit of the low resistance range predicted for the second power battery 5; SOC2 max_limit It is the upper limit of the low resistance range predicted for the second power battery 5 .

[0067] Table 1 Collection data

[0068] The input layer of the neural network receives multiple state variables of the battery, the hidden layer can include multiple fully connected layers, and the output layer directly outputs two values: the upper and lower limits of the low resistance interval of the SOC, which characterize the optimal energy consumption range. Input layer: Receive multiple state variables of the battery, with a dimension of 7. The hidden layer can be one or more fully connected layers, and the number of layers and neurons can be selected according to the complexity of the data. In this embodiment, two hidden layers are used as an example, each hidden layer has 64 neurons, and the ReLU activation function is used. The output layer directly outputs the upper and lower limits of the low internal resistance interval of the SOC. By inputting the real-time state of the battery (SOC, internal resistance, current, voltage, temperature, C-rate, number of cycles) into the neural network, the upper / lower limits of the SOC interval of the battery low resistance are dynamically predicted, and a dynamically changing battery low resistance interval is obtained, so as to obtain the upper and lower limits of the battery charge and discharge SOC power for the subsequent dual battery charge and discharge balance. Through the predicted battery low resistance intervals of the first power battery 4 and the second power battery 5, the current battery power SOC is compared with the low resistance interval power threshold in real time. The specific dynamic control logic is as follows: (1) The SOC of the first power battery 4 is greater than the upper limit of the low resistance range, so the discharge amount of the first power battery 4 is reduced and the discharge amount of the second power battery 5 is increased.

[0069] When the battery power drops to the predicted battery low resistance SOC power lower limit, the driving charging mode is turned on until the power returns to the predicted battery low resistance SOC power upper limit.

[0070] (2) The SOC of the second power battery 5 is greater than the upper limit of the low resistance range, so its discharge capacity is reduced and the discharge capacity of the first power battery 4 is increased.

[0071] When the battery power drops to the predicted battery low resistance SOC power lower limit, the driving charging mode is turned on until the power returns to the predicted battery low resistance SOC power upper limit.

[0072] (3) If the SOC of the second power battery 5 is less than the lower limit of the low resistance range, increase its charge amount until the charge level returns to the predicted upper limit of the battery low resistance SOC, and reduce the charge level of the first power battery 4.

[0073] (4) If the SOC of the first power battery 4 is less than the lower limit of the low resistance range, increase its charge amount until the charge level returns to the predicted upper limit of the battery low resistance SOC, and reduce the charge level of the second power battery 5.

[0074] (5) When the first power battery 4 and the second power battery 5 are both in the low resistance SOC range, the output power of the first power battery 4 and the second power battery 5 are dynamically allocated according to the real-time predicted low resistance range and the current battery power, as shown in formula (5): (4) (5) Among them, P 1battery is the output power of the first power battery 4; P 2battery is the output power of the second power battery 5; P2 is the required power when the generator 2 is used as a drive motor; P3 is the required power of the first drive motor 3; P6 is the required power of the second drive motor 6; P 22 is the power required by the CPTO drive motor 22; SOC 1_cur is the current power of the first power battery 4; SOC 1min_limit is the lower limit of the low resistance range predicted by the first power battery 4; SOC 1max_limit The upper limit of the low resistance range predicted for the first power battery 4; SOC 2_cur is the current power of the second power battery 5; SOC 2min_limit The lower limit of the low resistance range predicted for the second power battery 5; SOC2 max_limit It is the upper limit of the low resistance range predicted for the second power battery 5 .

[0075] Example 3 In one embodiment of the present disclosure, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the hybrid tractor power system is implemented.

[0076] Example 4 In one embodiment of the present disclosure, a non-transitory computer-readable storage medium is provided, wherein the non-transitory computer-readable storage medium is used to store computer instructions, and when the computer instructions are executed by a processor, the hybrid tractor power system is implemented.

[0077] Example 5 In one embodiment of the present disclosure, an electronic device is provided, including: a processor, a memory, and a computer program; wherein the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device is running, the processor executes the computer program stored in the memory, so that the electronic device executes and implements the hybrid tractor power system.

[0078] The present disclosure is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present disclosure. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0079] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0080] Although the above describes the specific implementation methods of the present disclosure in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present disclosure. Technical personnel in the relevant field should understand that on the basis of the technical solution of the present disclosure, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present disclosure.

Claims

1. A hybrid tractor power system, characterized in that: Including engine and CVT transmission; The CVT gearbox adopts a structure of dual power batteries, dual drive motors, and dual variable motors. The dual power batteries include a first power battery and a second power battery. The dual drive motors include a first drive motor and a second drive motor. The dual variable motors include a generator and a CPTO drive motor. The tractor provides three types of power paths: First power path: the engine directly provides power to the wheels through a gear pair; Second power path: the engine drives the generator to charge the dual power battery, and the dual power battery is connected to at least any motor of the dual drive motor and the dual variable motor to provide power for the wheels; The third power path: the engine drives the generator to charge the dual power batteries, and the dual power batteries drive the motor through the CPTO to provide power for the agricultural machinery.

2. A hybrid tractor power system according to claim 1, characterized in that: The engine is connected to the generator through the third clutch, the engine is connected to the wheels through the gear pair, the first clutch, and the planetary gear mechanism, and the generator is connected to the first power battery and the second power battery through the first control switch and the second control switch respectively.

3. A hybrid tractor power system as claimed in claim 1, characterized in that: The outputs of the first power battery and the second power battery are connected to the first drive motor through the third control switch and the fourth control switch, respectively, connected to the second drive motor through the fifth control switch and the sixth control switch, respectively, and connected to the CPTO drive motor through the seventh control switch and the eighth control switch; The first drive motor and the second drive motor are connected to the wheels through a gear pair and a planetary gear mechanism respectively; The CPTO drive motor is connected to the agricultural implement via a CPTO clutch, and is connected to the wheels via a gear pair, a second clutch, and a planetary gear mechanism.

4. The control method of a hybrid tractor power system according to any one of claims 1 to 3, characterized in that: According to the current working mode of the tractor, the power path is selected for control, specifically: In the low-load starting mode, the second power path is selected, and the first drive motor and the second drive motor are driven jointly; In the high-load starting mode, the second power path is selected. Under the premise that the first drive motor and the second drive motor are driven jointly, it is determined whether the generator and the CPTO drive motor participate in the driving according to the required power; In the low-load walking mode, the second power path is selected, and the first drive motor and the second drive motor are driven jointly; In high-load walking mode, there are two control modes according to the discharge rate of the power battery: When at least one of the discharge rates of the first power battery and the second power battery is greater than a threshold, a combination of the first power path and the second power path is selected, and under the premise of joint driving of the engine and the second drive motor, whether the CPTO drive motor participates in the driving is determined according to the required power; When the discharge rates of the first power battery and the second power battery are both lower than the threshold, the second power path is selected, and whether the generator and the CPTO drive motor participate in the driving is determined based on the required power, under the premise that the first drive motor and the second drive motor are jointly driven; In the current working mode, when there is a need for farming, a third power path is added for combined control; Among them, in the control process when the generator is not converted into a drive motor, the charging and discharging of the first power battery and the second power battery are differentially controlled according to the real-time predicted low resistance interval and the current battery power.

5. The control method of a hybrid tractor power system according to claim 4, characterized in that: The low resistance interval is based on battery power, internal resistance, current, voltage, temperature, charge and discharge rate, and number of cycles, and uses a trained neural network to predict the optimal energy consumption range of the battery to obtain the upper and lower limits of the low resistance interval.

6. The control method of a hybrid tractor power system according to claim 4, characterized in that: The differentiated control of charging and discharging of the first power battery and the second power battery is specifically as follows: When the power of the current power battery is greater than the upper limit of the low resistance range, its discharge capacity is reduced and the discharge capacity of another power battery is increased; When the power levels of the first power battery and the second power battery are both within the low resistance range, dynamically allocating the output power of the first power battery and the second power battery; When the power level of the first power battery or the second power battery is less than the lower limit of the low resistance interval, the engine drives the generator to charge the battery whose power level is less than the lower limit; When the power level of the first power battery or the second power battery is greater than the upper limit of the low resistance interval, the output power of the battery greater than the upper limit is reduced, and the output power of the other battery is increased.

7. The control method of a hybrid tractor power system according to claim 6, characterized in that: The output power is calculated as follows: Among them, P 1battery is the output power of the first power battery; P 2battery is the output power of the second power battery; P2 is the required power when the generator is used as a drive motor; P3 is the required power of the first drive motor; P6 is the required power of the second drive motor; P 22 The power required for CPTO drive motor; SOC 1_cur is the current power of the first power battery; SOC 1min_limit The lower limit of the low resistance range predicted for the first power battery; SOC 1max_limit The upper limit of the low resistance range predicted for the first power battery; SOC 2_cur The current power of the second power battery; SOC 2min_limit The lower limit of the low resistance range predicted for the second power battery; SOC2 max_limit The upper limit of the low resistance range predicted for the second power battery.

8. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the control method of a hybrid tractor power system according to any one of claims 4 to 7 is implemented.

9. A non-transitory computer-readable storage medium, characterized in that: The non-transitory computer-readable storage medium is used to store computer instructions, and when the computer instructions are executed by the processor, a control method for a hybrid tractor power system as described in any one of claims 4 to 7 is implemented.

10. An electronic device, characterized in that: include: A processor, a memory and a computer program; wherein the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device is running, the processor executes the computer program stored in the memory so that the electronic device executes a control method for a hybrid tractor power system as described in any one of claims 4 to 7.

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