Dual-motor power coupling device and control method thereof

Abstract

The invention relates to a dual-motor power coupling device and a control method thereof, comprising a driving motor mainly transmitting power to a variable-speed drive bridge, a PTO motor mainly used for driving a rotary tillage mechanism, and a double-row planetary gear coupler. The first planetary gear coupling mechanism, the second planetary gear coupling mechanism, the stepless transmission mechanism, the electromagnetic locker, and the synchronizer are provided to control the confluence and diversion of the power of the two motors. The double-row planetary gear coupler can coordinate the working areas of the two powers, which can not only effectively solve the limitation of the large volume of a high-power drive system, but also increase the application range of electric tractors, thereby improving the power and economy of the electric tractors.

Description

Technical Field

[0001] The invention relates to the field of electric tractors, and in particular to a dual-motor power coupling device and a control method thereof. Background Art

[0002] At present, most tractors on the market still use diesel engines as their power source. This traditional diesel tractor is not only noisy, inefficient, but also seriously pollutes the environment. Electric tractors use electricity to drive vehicles. Compared with traditional diesel tractors, electric tractors have the advantages of low emissions, clean and pollution-free, low noise, and high energy utilization. In addition, the motor has the advantage of flexible control, which further simplifies the transmission structure of the tractor. Therefore, electric tractors have become a new trend in the development of tractors.

[0003] In the research of electric tractors, single motor drive is mostly used, which is difficult to meet the complex working conditions of tractors. In hybrid tractors, the electric motor is used as auxiliary power, and the diesel engine is mainly used as the main power. This method does not give full play to the characteristics of high energy utilization and flexible control of the electric motor. Although tractors driven by dual motors have been disclosed in the prior art, there are generally problems such as the large size of the dual motor power coupling mechanism, the single operation mode, insufficient power, and low energy utilization. Summary of the invention

[0004] The purpose of the present invention is to provide a dual-motor power coupling device and a control method thereof, which can realize power convergence and diversion between the drive motor and the PTO motor, and improve the power and economy of the electric tractor by flexibly controlling the dual motors to adapt to the complex working conditions of the tractor, and significantly reduce the volume of the dual-motor coupling mechanism.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a dual-motor power coupling device, comprising a BMS controller, a power battery pack and a distribution box which are installed on an electric tractor and are connected in sequence in a circuit, the distribution box is respectively connected in circuit with a whole machine controller, a drive motor controller, a PTO motor controller and a coupler controller, the whole machine controller is used to control the operation of the electric tractor, the drive motor controller and the PTO motor controller respectively control the rotation of the drive motor and the PTO motor, and the coupler controller controls the operation of a double-row planetary gear coupler;

[0006] The double-row planetary gear coupler comprises a first planetary gear coupling mechanism and a second planetary gear coupling mechanism arranged side by side, wherein a first gear ring of the first planetary gear coupling mechanism and an adjacent second gear ring arranged on the second planetary gear coupling mechanism are externally meshed for transmission;

[0007] The first input shaft of the first planetary gear coupling mechanism is connected to the drive motor, and the first output shaft is connected to the drive axle of the electric tractor; the first ring gear of the first planetary gear coupling mechanism is connected to the first electromagnetic locker, and the first output shaft of the first planetary gear coupling mechanism and the drive axle are provided in sequence: a second electromagnetic locker, a synchronizer, a continuously variable transmission mechanism and a transmission for locking or unlocking the transmission of the first planet carrier in the first planetary gear coupling mechanism to the first output shaft;

[0008] The second input shaft of the second planetary gear coupling mechanism is connected to the PTO motor, and a third electromagnetic lock is provided at the second output shaft for locking or unlocking the transmission of the second sun gear to the second output shaft in the second planetary gear coupling mechanism. The second output shaft is connected to the continuously variable transmission mechanism, and the continuously variable transmission mechanism drives the rotary tillage mechanism to operate through the third output shaft.

[0009] Furthermore, the first planetary gear coupling mechanism includes a first sun gear connected to the first input shaft, a first ring gear having external teeth and internal teeth, a first electromagnetic locker for locking or unlocking the first ring gear, a first planetary gear, and a first planet carrier connected to the first output shaft, the first planetary gear is externally meshed with the first sun gear, the first planetary gear is internally meshed with the first ring gear and is positioned and supported by the first planet carrier.

[0010] Furthermore, the second planetary gear coupling mechanism includes a second planetary carrier connected to the second input shaft, a second planetary gear, a second ring gear having external teeth and internal teeth, and a second sun gear connected to the second output shaft. The second planetary gear is externally meshed with the second sun gear, and the second planetary gear is internally meshed with the second ring gear and is positioned and supported by the second planetary carrier.

[0011] Furthermore, the whole machine controller obtains BMS controller information, drive motor controller information, coupler controller information, PTO motor controller information and distribution box information through the high-speed CAN bus, and sends control signals to the BMS controller, drive motor controller, coupler controller, PTO motor controller and distribution box through the high-speed CAN bus; the whole machine controller obtains electric tractor operation information through the low-speed CAN bus.

[0012] Furthermore, the BMS controller controls the power battery pack, which supplies power to the drive motor, the PTO motor, the synchronizer, the first electromagnetic lock, the second electromagnetic lock and the third electromagnetic lock; the coupler controller controls the interruption and engagement of the synchronizer, the operation of the servo cylinder (2103), and the locking or unlocking of the first electromagnetic lock, the second electromagnetic lock and the third electromagnetic lock.

[0013] Furthermore, the BMS controller, drive motor controller, coupler controller, PTO motor controller, whole machine controller and distribution box constitute a control system of a dual-motor power coupling device, which is provided with a walking-only mode, an operation-only mode, a walking-operation separation mode, a walking-operation coupling mode and an energy recovery mode.

[0014] Furthermore, the electric tractor operation information includes a key signal, a gearbox gear signal, a pedal position signal, an operation mode signal, and a motor and a rotating shaft speed signal.

[0015] Furthermore, the continuously variable transmission mechanism includes an active working wheel arranged on the first output shaft and a driven working wheel arranged on the second input shaft, and the active working wheel and the driven working wheel are connected by a transmission belt; the active working wheel includes an active fixed working wheel and an active movable working wheel, and the driven working wheel includes a driven fixed working wheel and a driven movable working wheel, and a servo cylinder is connected between the active movable working wheel and the driven movable working wheel, and the servo cylinder drives the active movable working wheel and the driven movable working wheel to work to realize the stepless transmission of the continuously variable transmission mechanism.

[0016] Furthermore, the transmission is an intermediate shaft type transmission.

[0017] The control method of the dual-motor power coupling device comprises the following steps: after the electric tractor is started, the whole vehicle enters the system self-check, after the system self-check passes, the whole machine controller obtains the key signal, the synchronizer position signal, the first electromagnetic lock position signal, the second electromagnetic lock position signal, the third electromagnetic lock position signal, the gear position signal of the transmission, the pedal position signal, the operation mode signal, the motor and the rotating shaft speed signal, and the whole machine controller sends a control signal to the BMS controller, the drive motor controller, the coupler controller, the PTO motor controller and the distribution box according to the obtained information, so that the electric tractor selects different control modes:

[0018] 1) Travel-only mode: When the whole machine controller receives the travel-only mode, the whole machine controller calculates the real-time required power Px. When the rated power of the drive motor Pq ≥ Px, the coupler controller controls the first electromagnetic lock to engage and the synchronizer to interrupt. At this time, the drive motor is in working state. The whole machine controller calculates the target speed nq of the drive motor, and then transmits the signal to the drive motor controller. The drive motor adjusts the speed in real time according to the signal of the drive motor controller.

[0019] When Pq < Px, the coupler controller controls the third electromagnetic lock to engage and the synchronizer to disengage. At this time, both the drive motor and the PTO motor are in the working state. The machine controller calculates the target speed nq of the drive motor and the target speed np of the PTO motor based on the maximum working efficiency distribution control strategy, and then transmits the signals to the drive motor controller and the PTO motor controller. The drive motor adjusts its speed in real time according to the signal from the drive motor controller, and the PTO motor adjusts its speed in real time according to the signal from the PTO motor controller;

[0020] 2) Only operation mode: When the machine controller receives the only operation mode, the coupler controller controls the first electromagnetic lock to engage and the synchronizer to disengage. At this time, the PTO motor is in the working state. The machine controller calculates the target speed np of the PTO motor, and then transmits the signal to the PTO motor controller. The PTO motor operates at a constant speed according to the signal from the PTO motor controller. The sensor real-time collects the actual speed of the PTO motor. The machine controller compares the actual speed of the PTO motor with the target speed of the PTO motor and transmits the signal to the PTO motor controller in real time, and controls the speed of the PTO motor through the PTO motor controller to keep the PTO motor operating at a constant speed;

[0021] 3) Travel operation separation mode: When the machine controller receives the travel operation separation mode, the coupler controller controls the first electromagnetic lock to engage and the synchronizer to disengage. At this time, both the drive motor and the PTO motor are in the working state. The machine controller calculates the target speed nq of the drive motor and the target speed np of the PTO motor, and then transmits the signals to the drive motor controller and the PTO motor controller. The drive motor adjusts its speed in real time according to the signal from the drive motor controller, and the PTO motor operates at a constant speed according to the signal from the PTO motor controller. The sensor real-time collects the actual speed of the PTO motor. The machine controller compares the actual speed of the PTO motor with the target speed of the PTO motor and transmits the signal to the PTO motor controller in real time, and controls the speed of the PTO motor through the PTO motor controller to keep the PTO motor operating at a constant speed;

[0022] 4) Travel operation coupling mode: When the whole machine controller receives the travel operation coupling mode, the coupler controller controls the synchronizer combination and the servo cylinder of the stepless transmission mechanism to work. At this time, the drive motor and the PTO motor are in working state. The whole machine controller calculates the target speed nq of the drive motor, the target speed np of the PTO motor and the pressure of the servo cylinder based on the maximum work efficiency allocation control strategy and the required speed of the first output shaft and the third output shaft, and then transmits the signal to the drive motor controller, the PTO motor controller and the coupler controller. The drive motor adjusts the speed in real time according to the signal of the drive motor controller. The PTO motor adjusts its speed in real time according to the signal of the PTO motor controller, the servo cylinder controls the transmission ratio of the continuously variable transmission mechanism in real time according to the signal of the coupler controller, the sensor collects the actual rotation speeds of the first output shaft and the third output shaft in real time, the whole machine controller compares the actual rotation speeds of the first output shaft and the third output shaft with the required rotation speeds of the first output shaft and the third output shaft, and transmits the signal to the drive motor controller, the PTO motor controller and the coupler controller in real time, the drive motor adjusts its speed in real time according to the signal of the drive motor controller, the PTO motor adjusts its speed in real time according to the signal of the PTO motor controller, the servo cylinder controls the transmission ratio of the continuously variable transmission mechanism in real time according to the signal of the coupler controller, and keeps the first output shaft in real time speed regulation and the third output shaft working at a constant speed;

[0023] 5) Energy recovery mode: When the whole machine controller recognizes that the tractor is stationary and the PTO is not working or braking, the coupler controller controls the second electromagnetic lock and the third electromagnetic lock to engage and the synchronizer to interrupt. At this time, the drive motor is in working state and the PTO motor works as a generator. The whole machine controller calculates the speed nq of the drive motor in the lowest energy consumption state, and then transmits the signal to the drive motor controller. The drive motor adjusts the speed in real time according to the signal of the drive motor controller, and the PTO motor acts as an electric motor to transmit electrical energy to the power battery pack.

[0024] The beneficial effects brought by the present invention are:

[0025] 1. The double-row planetary gear coupler provided in the present invention has a more compact structure and a greater load-bearing capacity because the ring gear on the first planetary gear coupling mechanism and the ring gear provided on the second planetary gear coupling mechanism are externally meshed for transmission; compared with the dual-motor coupling mechanism of an electric tractor of the same level, the volume of the double planetary gear coupler of the present invention is reduced by 20%, on this basis, the capacity of the power battery can be increased, thereby increasing the cruising range of the electric tractor.

[0026] 2. Using dual motors as the power source of the electric tractor, the drive motor transmits power to the variable speed drive axle alone, and the PTO motor drives power to the rotary tillage mechanism alone. By controlling the dual planetary gear coupler, the power of the drive motor and the PTO motor can be converged to the variable speed drive axle, which can simplify the gearbox structure and facilitate the layout of the whole vehicle. According to different operating requirements, the appropriate working mode can be selected to improve the working efficiency and energy utilization of the motor.

[0027] 3. By controlling the lock, synchronizer and continuously variable transmission mechanism, flexible conversion among five operating modes, namely, walking-only mode, working-only mode, walking-working separation mode, walking-working coupling mode and energy recovery mode, can be achieved, thus meeting the multi-scenario operating requirements of electric tractors and improving the power, economy and adaptability of the whole vehicle.

[0028] 4. When the electric tractor is in a short-term stop or braking mode, the system enters the energy recovery mode. The PTO motor acts as an electric motor to transmit electrical energy to the power battery pack. The electrical energy is stored in the low-voltage battery to improve the energy utilization rate of the whole machine.

[0029] 5. By controlling the servo cylinder to change the transmission ratio of the continuously variable transmission mechanism, the dual power coupling mechanism can distribute the power of the drive motor and the PTO motor to the drive axle and the rotary tillage mechanism based on the maximum work efficiency distribution control strategy.

[0030] 6. The power source used in the present invention is an electric motor, and the power battery pack provides electrical energy to achieve zero pollution emissions, effectively solving the harm of traditional tractor emissions to crops and the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the structure of a dual-motor power coupling device;

[0032] Figure 2 It is a schematic diagram of the structure of a double-row planetary gear coupler;

[0033] Figure 3 is a structural schematic diagram of the first planetary gear coupling mechanism;

[0034] Figure 4 is a structural schematic diagram of the second planetary gear coupling mechanism;

[0035] Figure 5 It is a structural schematic diagram of the stepless transmission mechanism;

[0036] Figure 6 It is a circuit connection relationship diagram of the control system of the dual-motor power coupling device;

[0037] Figure 7 The process of the control method of the dual-motor power coupling device is Figure 1 ;

[0038] Figure 8 The process of the control method of the dual-motor power coupling device is Figure 2 .

[0039] The following are the descriptions of the figures:

[0040] 1. BMS controller, 2. Power battery pack, 3. Drive motor controller, 4. Drive motor, 5. Double-row planetary gear coupler, 6. Transmission, 7. Drive axle, 8. Rotary tillage mechanism, 9. Coupler controller, 10. PTO motor, 11. Distribution box, 12. PTO motor controller, 13. Machine controller, 14. First input shaft, 15. First planetary gear coupling mechanism, 1501. First sun gear, 1502. First ring gear, 1503. First planetary gear, 1504. First planet carrier, 16. First electromagnetic locker, 17. First output shaft, 18. Second electromagnetic locker, 19. Synchronizer, 20. Third output shaft, 21. Stepless transmission mechanism, 2101. Active fixed working wheel, 2102. Active movable working wheel, 2103. Servo cylinder, 2104. Transmission belt, 2105. Driven fixed working wheel, 2106. Driven movable working wheel, 22. Second output shaft, 23. Third electromagnetic locker, 24. Second planetary gear coupling mechanism, 2401. Second planetary carrier, 2402. Second planetary gear, 2403. Second ring gear, 2404. Second sun gear, 25. Second input shaft. DETAILED DESCRIPTION

[0041] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the "first", "second" and "third" in the following embodiments are only used to distinguish the names of the devices and do not have specific meanings.

[0042] Reference Figure 1 The dual-motor power coupling device includes a BMS controller 1, a power battery pack 2, a drive motor controller 3, a drive motor 4, a double-row planetary gear coupler 5, a transmission 6, a drive axle 7, a rotary tillage mechanism 8, a coupler controller 9, a PTO motor 10, a distribution box 11, a PTO motor controller 12 and a whole machine controller 13.

[0043] The BMS controller 1, the power battery pack 2 and the distribution box 11 are connected in circuit in sequence, and the distribution box 11 is respectively connected in circuit with the whole machine controller 13, the drive motor controller 3, the PTO motor controller 12, and the coupler controller 9. The whole machine controller 13 is used to control the operation of the double-row planetary gear electric tractor, the drive motor controller 3 and the PTO motor controller 12 respectively control the rotation of the drive motor 4 and the PTO motor 10, and the coupler controller 9 is used to control the operation of the double-row planetary gear coupler 5.

[0044] Reference Figure 2 The double-row planetary gear coupler 5 includes a first planetary gear coupling mechanism 15 and a second planetary gear coupling mechanism 24 arranged side by side. The first input shaft 14 of the first planetary gear coupling mechanism 15 is connected to the drive motor 4, and the first output shaft 17 is connected to the drive axle 7 of the electric tractor. The second input shaft 25 of the second planetary gear coupling mechanism 24 is connected to the PTO motor 10, and the second output shaft 22 is connected to the stepless transmission mechanism 21, and the stepless transmission mechanism 21 drives the rotary tillage mechanism 8 to operate through the third output shaft 20.

[0045] A first input shaft 14, a first planetary gear coupling mechanism 15, a first output shaft 17, a second electromagnetic locker 18 for locking or unlocking the transmission of the first planet carrier 1504 in the first planetary gear coupling mechanism 15 to the first output shaft 17, a synchronizer 19, a continuously variable transmission mechanism 21 and a transmission 6 are provided between the drive motor 4 and the drive axle 7. The transmission 6 is an intermediate shaft type transmission, which realizes changing the transmission ratio, switching the transmission direction and interrupting the power transmission.

[0046] A second input shaft 25, a second planetary gear coupling mechanism 24, a third electromagnetic locker 23 for locking or unlocking the transmission of the second sun gear 2404 in the second planetary gear coupling mechanism 24 to the second output shaft 22, a second output shaft 22, a continuously variable transmission mechanism 21 and a third output shaft 20 are provided between the PTO motor 10 and the rotary tillage mechanism 8. The continuously variable transmission mechanism 21 includes an active working wheel arranged on the first output shaft 17 and a driven working wheel arranged on the second input shaft 25, and the active working wheel and the driven working wheel are connected by a transmission belt 2104; the active working wheel includes an active fixed working wheel 2101 and an active movable working wheel 2102, and the driven working wheel includes a driven fixed working wheel 2105 and a driven movable working wheel 2106, and a servo cylinder 2103 is connected between the active movable working wheel 2102 and the driven movable working wheel 2106, and the servo cylinder 2103 drives the active movable working wheel 2102 and the driven movable working wheel 2106 to work to realize the stepless transmission of the continuously variable transmission mechanism 21.

[0047] Reference Figure 3The first planetary gear coupling mechanism 15 includes a first sun gear 1501 connected to the first input shaft 14, a first gear ring 1502 with external teeth and internal teeth, a first electromagnetic locker 16 for locking or unlocking the first gear ring 1502, a first planetary gear 1503, and a first planet carrier 1504 connected to the first output shaft 17. The first planetary gear 1503 is externally meshed with the first sun gear 1501, and the first planetary gear 1503 is internally meshed with the first gear ring 1502 and is positioned and supported by the first planet carrier 1504. The first gear ring 1502 of the first planetary gear coupling mechanism 15 is externally meshed with the second gear ring 2403 adjacent to it and arranged on the second planetary gear coupling mechanism 24.

[0048] Reference Figure 4 The second planetary gear coupling mechanism 24 includes a second planetary carrier 2401 connected to the second input shaft 25, a second planetary gear 2402, a second ring gear 2403 with external teeth and internal teeth, and a second sun gear 2404 connected to the second output shaft 22. The second planetary gear 2402 is externally meshed with the second sun gear 2404, and the second planetary gear 2402 is internally meshed with the second ring gear 2403 and is positioned and supported by the second planetary carrier 2401. The second ring gear 2403 is externally meshed with the first ring gear 1502 provided on the first planetary gear coupling mechanism 15 for transmission.

[0049] Reference Figure 5 , the BMS controller 1, the drive motor controller 3, the coupler controller 9, the distribution box 11, the PTO motor controller 12 and the whole machine controller 13 constitute the control system of the dual-motor power coupling device. The system is provided with five operation modes: walking-only mode, operation-only mode, walking-operation separation mode, walking-operation coupling mode and energy recovery mode. The whole machine controller 13 obtains the information of the BMS controller 1, the drive motor controller 3, the coupler controller 9, the distribution box 11 and the PTO motor controller 12 through the high-speed CAN bus; sends control signals to the BMS controller 1, the drive motor controller 3, the coupler controller 9, the distribution box 11 and the PTO motor controller 12 through the high-speed CAN bus; the whole machine controller 13 obtains the operation information of the electric tractor through the low-speed CAN bus, so that the driver can understand the whole vehicle information in real time. The operation information of the electric tractor includes key signals, gearbox gear signals, pedal position signals, operation mode signals, motor and rotating shaft speed signals.

[0050] The power battery pack 2 is used to supply power to the drive motor 4, the PTO motor 10, the synchronizer 19, and each electromagnetic lock. The power battery pack 2 is connected to the low-voltage battery. The whole-machine controller 13 transmits control signals to the BMS controller 1 through the high-speed CAN bus to control the power battery pack 2; and transmits them to the coupler controller 9 to control the interruption and engagement of the synchronizer 19, the operation of the servo cylinder (2103), and the locking or unlocking of the first electromagnetic lock 16, the second electromagnetic lock 18, and the third electromagnetic lock 23.

[0051] Refer to Figure 6 and Figure 7 , after the electric tractor starts, the whole vehicle enters the system self-check. After the system self-check passes, the whole-machine controller 13 obtains the key signal, the synchronizer 19 position signal, the position signals of each electromagnetic lock, the gearbox gear position signal, the pedal position signal, the operation mode signal, and the motor and rotating shaft speed signals. The whole-machine controller 13 sends control signals to the BMS controller 1, the drive motor controller 3, the coupler controller 9, the PTO motor controller 12, and the distribution box 11 according to the obtained information, so that the electric tractor selects different control modes:

[0052] 1) Only walking mode: When the whole-machine controller 13 receives the only walking mode, the whole-machine controller 13 calculates the real-time required power Px. When the rated power Pq of the drive motor is greater than or equal to Px, the coupler controller 9 controls the first electromagnetic lock 16 to engage and the synchronizer 19 to interrupt. At this time, the drive motor 4 is in the working state. The whole-machine controller 13 calculates the target speed nq of the drive motor 4, and then transmits the signal to the drive motor controller 3. The drive motor 4 adjusts the speed in real time according to the signal of the drive motor controller 3;

[0053] When Pq < Px, the coupler controller 9 controls the third electromagnetic lock 23 to engage and the synchronizer 19 to interrupt. At this time, both the drive motor 4 and the PTO motor 10 are in the working state. The whole-machine controller 13 calculates the target speed nq of the drive motor 4 and the target speed np of the PTO motor 10 based on the maximum working efficiency distribution control strategy, and then transmits the signal to the drive motor controller 3 and the PTO motor controller 12. The drive motor 4 adjusts the speed in real time according to the signal of the drive motor controller 3, and the PTO motor 10 adjusts the speed in real time according to the signal of the PTO motor controller 12;

[0054] 2) Operation mode only: When the whole machine controller 13 receives the operation mode only, the coupler controller 9 controls the first electromagnetic lock 16 to engage and the synchronizer 19 to interrupt. At this time, the PTO motor 10 is in working state. The whole machine controller 13 calculates the target speed np of the PTO motor 10, and then transmits the signal to the PTO motor controller 12. The PTO motor 10 operates at a constant speed according to the signal of the PTO motor controller 12. The sensor collects the actual speed of the PTO motor 10 in real time. The whole machine controller 13 compares the actual speed of the PTO motor 10 with the target speed of the PTO motor 10 and transmits the signal to the PTO motor controller 12 in real time. The speed of the PTO motor 10 is controlled by the PTO motor controller 12 to keep the PTO motor 10 working at a constant speed.

[0055] 3) Walking operation separation mode: When the whole machine controller 13 receives the walking operation separation mode, the coupler controller 9 controls the first electromagnetic lock 16 to engage and the synchronizer 19 to interrupt. At this time, the drive motor 4 and the PTO motor 10 are both in working state. The whole machine controller 13 calculates the target speed nq of the drive motor 4 and the target speed np of the PTO motor 10, and then transmits the signal to the drive motor controller 3 and the PTO motor controller 12. The drive motor 4 adjusts the speed in real time according to the signal of the drive motor controller 3, and the PTO motor 10 operates at a constant speed according to the signal of the PTO motor controller 12. The sensor collects the actual speed of the PTO motor 10 in real time. The whole machine controller 13 compares the actual speed of the PTO motor 10 with the target speed of the PTO motor 10 and transmits the signal to the PTO motor controller 12 in real time. The speed of the PTO motor 10 is controlled by the PTO motor controller 12 to keep the PTO motor 10 working at a constant speed.

[0056] 4) Walking operation coupling mode: When the whole machine controller 13 receives the walking operation coupling mode, the coupler controller 9 controls the synchronizer 19 to work with the servo cylinder 2103. At this time, the drive motor 4 and the PTO motor 10 are in working state. The whole machine controller 13 calculates the target speed nq of the drive motor 4, the target speed np of the PTO motor 10 and the pressure of the servo cylinder 2103 based on the maximum work efficiency distribution control strategy and the required speed of the first and third output shafts, and then transmits the signal to the drive motor controller 3, the PTO motor controller 12 and the coupler controller 9. The drive motor 4 adjusts its speed in real time according to the signal of the drive motor controller 3, the PTO motor 10 adjusts its speed in real time according to the signal of the PTO motor controller 12, and the servo cylinder 210 3. The transmission ratio of the continuously variable transmission mechanism 21 is controlled in real time according to the signal of the coupler controller 9. The sensor collects the actual rotation speed of the first and third output shafts in real time. The whole machine controller 13 compares the actual rotation speed of the first and third output shafts with the required rotation speed of the first and third output shafts and transmits the signal to the drive motor controller 3, the PTO motor controller 12 and the coupler controller 9 in real time. The drive motor 4 is adjusted in real time according to the signal of the drive motor controller 3. The PTO motor 10 is adjusted in real time according to the signal of the PTO motor controller 12. The servo cylinder 2103 controls the transmission ratio of the continuously variable transmission mechanism 21 in real time according to the signal of the coupler controller 9, and keeps the first output shaft 17 in real time and the third output shaft 20 working at a constant speed.

[0057] 5) Energy recovery mode: When the whole machine controller 13 recognizes that the tractor is stationary and the PTO is not operating or braking, the coupler controller 9 controls the second electromagnetic lock 18 and the third electromagnetic lock 23 to engage and the synchronizer to be interrupted. At this time, the drive motor 4 is in working state, and the PTO motor works as a generator. The whole machine controller 13 calculates the speed nq of the drive motor 4 in the lowest energy consumption state, and then transmits the signal to the drive motor controller 3. The drive motor 4 adjusts the speed in real time according to the signal of the drive motor controller 3, and the PTO motor 10 acts as an electric motor to transmit electrical energy to the power battery pack 2.

[0058] In addition, according to actual needs, those skilled in the art can also select other possible working states.

[0059] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. Dual-motor power coupling device, characterized in that: The electric tractor comprises a BMS controller (1), a power battery pack (2) and a distribution box (11) which are connected in sequence in a circuit and are installed on the electric tractor. The distribution box (11) is connected in a circuit to a whole machine controller (13), a drive motor controller (3), a PTO motor controller (12) and a coupler controller (9). The whole machine controller (13) is used to control the operation of the electric tractor. The drive motor controller (3) and the PTO motor controller (12) respectively control the rotation of the drive motor (4) and the PTO motor (10). The coupler controller (9) controls the operation of the double-row planetary gear coupler (5). The double-row planetary gear coupler (5) comprises a first planetary gear coupling mechanism (15) and a second planetary gear coupling mechanism (24) arranged side by side, a first ring gear (1502) of the first planetary gear coupling mechanism (15) and an adjacent second ring gear (2403) arranged on the second planetary gear coupling mechanism (24) being externally meshed for transmission; The first input shaft (14) of the first planetary gear coupling mechanism (15) is connected to a drive motor (4), and the first output shaft (17) is connected to a drive axle (7) of an electric tractor; the first ring gear (1502) of the first planetary gear coupling mechanism (15) is connected to a first electromagnetic locker (16), and the first output shaft (17) of the first planetary gear coupling mechanism (15) and the drive axle (7) are provided in sequence: a second electromagnetic locker (18) for locking or unlocking the transmission of the first output shaft (17) by the first planet carrier (1504) in the first planetary gear coupling mechanism (15), a synchronizer (19), a continuously variable transmission mechanism (21) and a transmission (6); The second input shaft (25) of the second planetary gear coupling mechanism (24) is connected to the PTO motor (10); a third electromagnetic locker (23) for locking or unlocking the transmission of the second sun gear (2404) in the second planetary gear coupling mechanism (24) to the second output shaft (22) is provided at the second output shaft (22); the second output shaft (22) is connected to the stepless transmission mechanism (21); and the stepless transmission mechanism (21) drives the rotary tillage mechanism (8) to operate via the third output shaft (20).

2. The dual-motor power coupling device according to claim 1, characterized in that: The first planetary gear coupling mechanism (15) comprises a first sun gear (1501) connected to a first input shaft (14), a first ring gear (1502) provided with external teeth and internal teeth, a first electromagnetic locker (16) for locking or unlocking the first ring gear (1502), a first planetary gear (1503), and a first planet carrier (1504) connected to a first output shaft (17); the first planetary gear (1503) is externally meshed with the first sun gear (1501), the first planetary gear (1503) is internally meshed with the first ring gear (1502), and is positioned and supported by the first planet carrier (1504).

3. The dual-motor power coupling device according to claim 2, characterized in that: The second planetary gear coupling mechanism (24) comprises a second planet carrier (2401) connected to the second input shaft (25), a second planetary gear (2402), a second ring gear (2403) provided with external teeth and internal teeth, and a second sun gear (2404) connected to the second output shaft (22); the second planetary gear (2402) is externally meshed with the second sun gear (2404), the second planetary gear (2402) is internally meshed with the second ring gear (2403), and is positioned and supported by the second planet carrier (2401).

4. The dual-motor power coupling device according to claim 3, characterized in that: The whole machine controller (13) obtains BMS controller (1) information, drive motor controller (3) information, coupler controller (9) information, PTO motor controller (12) information and distribution box (11) information via the high-speed CAN bus, and sends control signals to the BMS controller (1), drive motor controller (3), coupler controller (9), PTO motor controller (12) and distribution box (11) via the high-speed CAN bus; the whole machine controller (13) obtains electric tractor operation information via the low-speed CAN bus.

5. The dual-motor power coupling device according to claim 4, characterized in that: The BMS controller (1) controls the power battery pack (2), and the power battery pack (2) supplies power to the drive motor (4), the PTO motor (10), the synchronizer (19), the first electromagnetic lock (16), the second electromagnetic lock (18), and the third electromagnetic lock (23); the coupler controller (9) controls the interruption and engagement of the synchronizer (19), the operation of the servo cylinder (2103), and the locking or unlocking of the first electromagnetic lock (16), the second electromagnetic lock (18), and the third electromagnetic lock (23).

6. The dual-motor power coupling device according to claim 5, characterized in that: The BMS controller (1), the drive motor controller (3), the coupler controller (9), the PTO motor controller (12), the whole machine controller (13) and the distribution box (11) constitute a control system of a dual-motor power coupling device, the system being provided with a walking-only mode, an operation-only mode, a walking-operation separation mode, a walking-operation coupling mode and an energy recovery mode.

7. The dual-motor power coupling device according to claim 4, characterized in that: The electric tractor operation information includes a key signal, a gearbox gear position signal, a pedal position signal, an operation mode signal, and a motor and a rotating shaft speed signal.

8. The dual-motor power coupling device according to claim 1, characterized in that: The continuously variable transmission mechanism (21) comprises an active working wheel arranged on a first output shaft (17) and a driven working wheel arranged on a second input shaft (25), wherein the active working wheel and the driven working wheel are connected via a transmission belt (2104); the active working wheel comprises an active fixed working wheel (2101) and an active movable working wheel (2102), and the driven working wheel comprises a driven fixed working wheel (2105) and a driven movable working wheel (2106); a servo cylinder (2103) is connected between the active movable working wheel (2102) and the driven movable working wheel (2106), and the servo cylinder (2103) drives the active movable working wheel (2102) and the driven movable working wheel (2106) to work, thereby realizing the continuously variable transmission of the continuously variable transmission mechanism (21).

9. The dual-motor power coupling device according to claim 1, characterized in that: The transmission (6) is an intermediate shaft type transmission.

10. The control method of the dual-motor power coupling device according to claim 6, characterized in that: After the electric tractor starts, the whole vehicle enters the system self-check. After the system self-check passes, the whole vehicle controller (13) obtains the key signal, the position signal of the synchronizer (19), the position signal of the first electromagnetic lock (16), the position signal of the second electromagnetic lock (18), the position signal of the third electromagnetic lock (23), the gearbox gear signal, the pedal position signal, the operation mode signal, and the motor and rotating shaft speed signals. According to the obtained information, the whole vehicle controller (13) sends control signals to the BMS controller (1), the drive motor controller (3), the coupler controller (9), the PTO motor controller (12), and the distribution box (11), so that the electric tractor selects different control modes: 1) Only walking mode: When the whole vehicle controller (13) receives the only walking mode, the whole vehicle controller (13) calculates the real-time required power Px. When the rated power of the drive motor Pq ≥ Px, the coupler controller (9) controls the first electromagnetic lock (16) to engage and the synchronizer (19) to disengage. At this time, the drive motor (4) is in the working state. The whole vehicle controller (13) calculates the target speed nq of the drive motor (4), and then transmits the signal to the drive motor controller (3). The drive motor (4) adjusts the speed in real time according to the signal of the drive motor controller (3); When Pq < Px, the coupler controller (9) controls the third electromagnetic lock (23) to engage and the synchronizer (19) to disengage. At this time, both the drive motor (4) and the PTO motor (10) are in the working state. The whole vehicle controller (13) calculates the target speed nq of the drive motor (4) and the target speed np of the PTO motor (10) based on the maximum working efficiency distribution control strategy, and then transmits the signal to the drive motor controller (3) and the PTO motor controller (12). The drive motor (4) adjusts the speed in real time according to the signal of the drive motor controller (3), and the PTO motor (10) adjusts the speed in real time according to the signal of the PTO motor controller (12); 2) Only operation mode: When the whole vehicle controller (13) receives the only operation mode, the coupler controller (9) controls the first electromagnetic lock (16) to engage and the synchronizer (19) to disengage. At this time, the PTO motor (10) is in the working state. The whole vehicle controller (13) calculates the target speed np of the PTO motor (10), and then transmits the signal to the PTO motor controller (12). The PTO motor (10) operates at a constant speed according to the signal of the PTO motor controller (12). The sensor collects the actual speed of the PTO motor (10) in real time. The whole vehicle controller (13) transmits the signal to the PTO motor controller (12) in real time by comparing the actual speed of the PTO motor (10) with the target speed of the PTO motor (10), and controls the speed of the PTO motor (10) through the PTO motor controller (12) to keep the PTO motor (10) operating at a constant speed; 3) Walking operation separation mode: When the whole machine controller (13) receives the walking operation separation mode, the coupler controller (9) controls the first electromagnetic lock (16) to engage and the synchronizer (19) to interrupt. At this time, the drive motor (4) and the PTO motor (10) are both in working state. The whole machine controller (13) calculates the target speed nq of the drive motor (4) and the target speed np of the PTO motor (10), and then transmits the signal to the drive motor controller (3) and the PTO motor controller (12). The drive motor (4) adjusts the speed in real time according to the signal of the drive motor controller (3). The PTO motor (10) operates at a constant speed according to the signal of the PTO motor controller (12). The sensor collects the actual speed of the PTO motor (10) in real time. The whole machine controller (13) compares the actual speed of the PTO motor (10) with the target speed of the PTO motor (10) and transmits the signal to the PTO motor controller (12) in real time. The speed of the PTO motor (10) is controlled by the PTO motor controller (12) to keep the PTO motor (10) operating at a constant speed. 4) Walking operation coupling mode: When the whole machine controller (13) receives the walking operation coupling mode, the coupler controller (9) controls the synchronizer (19) to work in conjunction with the servo cylinder (2103) of the stepless transmission mechanism (21). At this time, the drive motor (4) and the PTO motor (10) are in working state. The whole machine controller (13) calculates the target speed nq of the drive motor (4), the target speed np of the PTO motor (10) and the pressure of the servo cylinder (2103) based on the maximum work efficiency distribution control strategy and the required speed of the first output shaft (17) and the third output shaft (20). Then, the signal is transmitted to the drive motor controller (3), the PTO motor controller (12) and the coupler controller (9). The drive motor (4) adjusts its speed in real time according to the signal of the drive motor controller (3), the PTO motor (10) adjusts its speed in real time according to the signal of the PTO motor controller (12), and the servo cylinder (21 03) According to the signal of the coupler controller (9), the transmission ratio of the continuously variable transmission mechanism (21) is controlled in real time, the sensor collects the actual rotation speed of the first output shaft (17) and the third output shaft (20) in real time, the whole machine controller (13) compares the actual rotation speed of the first output shaft (17) and the third output shaft (20) with the required rotation speed of the first output shaft (17) and the third output shaft (20), and transmits the signal to the drive motor controller (3), the PTO motor controller (12) and the coupler controller (9) in real time, the drive motor (4) adjusts the speed in real time according to the signal of the drive motor controller (3), the PTO motor (10) adjusts the speed in real time according to the signal of the PTO motor controller (12), and the servo cylinder (2103) controls the transmission ratio of the continuously variable transmission mechanism (21) in real time according to the signal of the coupler controller (9), so as to keep the first output shaft (17) in real time speed adjustment and the third output shaft (20) in constant speed operation; 5) Energy recovery mode: When the whole machine controller (13) recognizes that the tractor is stationary and the PTO is not operating or is braking, the coupler controller (9) controls the second electromagnetic lock (18) and the third electromagnetic lock (23) to engage and the synchronizer to interrupt. At this time, the drive motor (4) is in a working state, and the PTO motor (10) works as a generator. The whole machine controller (13) calculates the speed nq of the drive motor (4) in the lowest energy consumption state, and then transmits the signal to the drive motor controller (3). The drive motor (4) adjusts the speed in real time according to the signal of the drive motor controller (3), and the PTO motor (10) acts as a motor to transmit electric energy to the power battery pack (2).

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