CN118494160A - A single-gear-ring dual-planetary-row hybrid power coupling structure and control method thereof - Google Patents

Abstract

The invention provides a single gear ring double planetary row hybrid power coupling structure and a control method thereof, relates to the technical field of hybrid power, aims at the problem of higher power requirement on a driving motor in the prior hybrid power driving system, adopts a double planetary row double motor structure, shares a gear ring with a front planetary row and a rear planetary row, the sun gear of the front planetary row and the sun gear of the rear planetary row are respectively connected with a motor, the working state of the planetary row is changed when the working state is switched, the use of a brake and a clutch is reduced, the simultaneous output of two motors can be realized when the electric motor is driven purely, the output power in the pure electric driving state is improved, and the power requirement on the motor is reduced.

Description

A single-gear-ring dual-planetary-row hybrid power coupling structure and control method thereof

Technical Field

The present invention relates to the field of hybrid technology, and in particular to a single-gear-ring and double-planetary-row hybrid power coupling structure and a control method thereof.

Background Art

The key system of a hybrid vehicle is the hybrid power system. Existing dual-motor hybrid systems usually distinguish between generators and drive motors. The generator is only used to generate electricity and supply the vehicle's power battery, and does not participate in driving the vehicle. In the pure electric drive state, only a single motor is used for driving, which requires a higher power for the drive motor.

A Chinese patent (publication number: CN110077219B) discloses a dual planetary gear hybrid system and a control method, in which the front ring gear of the front planetary gear is connected to the rear planet carrier of the rear planetary gear, the output end of the first motor is connected to the front sun gear of the front planetary gear, the output end of the second motor is connected to the rear sun gear of the rear planetary gear, and a flywheel assembly is provided, which is connected to the front ring gear through a second mode clutch. A dual planetary gear is adopted and a flywheel energy storage system is added to achieve a physical energy storage effect, the engine can work efficiently for a long time, and the power of the first motor and the second motor can be appropriately reduced; it adopts a mutually independent dual ring gear structure, and realizes power diversion through a clutch, and multiple brakes and clutches need to be arranged additionally, resulting in a more complex structure and higher cost. The dual motors used are still one ISG motor for power generation and one TM motor for driving. In the pure electric drive state, only a single motor is used for driving, and there is still a problem of high power demand for the drive motor.

Summary of the invention

The purpose of the present invention is to address the defects of the prior art and provide a single-gear ring and double-planetary row hybrid power coupling structure and a control method thereof. The structure of the double planetary row and double motors is adopted. The first planetary row and the second planetary row share a common gear ring. The sun gear of the first planetary row and the sun gear of the second planetary row are respectively connected to motors. When switching the working state, the working state of the planetary row is changed to reduce the use of brakes and clutches, and the dual motors can be output simultaneously in pure electric drive, thereby improving the output power in the pure electric drive state and reducing the power demand for the motor.

The first object of the present invention is to provide a single-gear-ring dual-planetary-row hybrid power coupling structure, which adopts the following scheme:

It includes an engine, a first planetary row, a second planetary row, a first motor and a second motor. The first planetary row includes a first sun gear, a first planetary gear, a first planetary carrier and a ring gear. The second planetary row includes a second sun gear, a second planetary gear, a second planetary carrier and a ring gear. The first planetary row and the second planetary row share the same ring gear. The output end of the engine is connected to the first planetary carrier through an input shaft, the input and output ends of the first motor are connected to the first sun gear, the input and output ends of the second motor are connected to the second sun gear, and the second planetary carrier is connected to an output shaft.

Furthermore, a first inner gear ring is provided at one end of the gear ring, and a second inner gear ring is provided at the other end, the first planetary gear is meshed with the first inner gear ring, and the second planetary gear is meshed with the second inner gear ring.

Furthermore, taking the perpendicular bisector of the axial midpoint of the gear ring as a reference plane, the first inner gear ring and the second inner gear ring are symmetrically distributed relative to the reference plane, and the first inner gear ring and the second inner gear ring rotate synchronously.

Furthermore, the first motor and the second motor are both generator motors.

Furthermore, a torsional vibration damper is connected between the input shaft and the output end of the engine, and the output shaft is connected to the wheel end through a differential.

A second object of the present invention is to provide a control method for a single-gear-ring dual-planetary-gear hybrid coupling structure, which is applied to a single-gear-ring dual-planetary-gear hybrid coupling structure as described in the first object, comprising:

When charging on the spot, the engine is involved in the work, the engine drives the first motor and the second motor to generate electricity respectively, and the generated electricity is stored in the power battery;

During pure electric operation, the engine does not work, and the first motor and/or the second motor work to drive the output shaft for output;

During hybrid operation, the engine participates in the work, and the engine diverts power to the first motor for power generation and output to the output shaft, while the second motor works and cooperates with the electric motor to drive the output shaft.

Furthermore, during direct drive operation, the engine works independently to drive the output shaft to output, and the first motor and the second motor do not work;

During hybrid operation, the engine participates in the work, and the engine, the first motor and the second motor work together to drive the output shaft;

During energy recovery, the engine does not participate in the work, the output shaft reversely drags the second motor to generate electricity, and the generated energy is stored in the power battery.

Further, when the vehicle speed is not zero and is lower than a first set speed, obtaining the vehicle running state;

If the vehicle is in an accelerating state, the first motor and the second motor work together to drive the output shaft;

If the vehicle is in a constant speed state, the first motor or the second motor works to drive the output shaft;

If the vehicle is in a decelerating state, energy recovery is performed.

Furthermore, when the vehicle speed is not lower than the first set speed and not higher than the second set speed, hybrid operation is performed, the engine participates in the work and is in a working condition that meets the set fuel economy, driving the output shaft to operate, and the second motor serves as an auxiliary power to assist in driving the output shaft to operate.

Further, when the vehicle speed is higher than the second set speed, the vehicle running state is obtained,

If the vehicle is in an accelerating state, a hybrid operation is performed, and the engine, the first motor and the second motor work together to drive the output shaft;

If the vehicle is in a constant speed state, direct drive operation is performed, the engine works, and the output shaft is driven;

If the vehicle is in a decelerating state, energy recovery is performed.

Compared with the prior art, the present invention has the following advantages and positive effects:

(1) In order to solve the problem of high power requirements for drive motors in current hybrid drive systems, a dual planetary gear and dual motor structure is adopted. The front planetary gear and the rear planetary gear share a common ring gear. The sun gear of the front planetary gear and the sun gear of the rear planetary gear are respectively connected to motors. When switching the working state, the working state of the planetary gear is changed to reduce the use of brakes and clutches. In addition, the dual motors can output simultaneously in pure electric drive, thereby increasing the output power in the pure electric drive state and reducing the power demand for the motors.

(2) Taking full advantage of the characteristics of the engine and motor, the symmetrical structure of single gear ring, double planetary gear and dual motor is adopted. The dual motors can be used for driving and power generation. The dual motors can be driven simultaneously or separately as required, achieving parallel-parallel operation or hybrid operation, thus improving the flexibility of hybrid power output.

(3) By utilizing the dual motors to coordinate the operation of the engine, the engine can maintain a fuel-efficient operating condition at a relatively high vehicle speed. The changes in vehicle speed can be achieved through motor-assisted drive, thereby reducing the engine's operating fuel consumption and ensuring the vehicle's operating power.

(4) The combination of different modes and states of the three input terminals of the engine, the first motor and the second motor can produce a variety of different working modes. The first motor and the second motor can generate electricity and drive output. In the pure electric dual-motor output mode, the motor power utilization rate is high and the acceleration performance is good. At the same time, the design requirements of the motor are reduced and the layout of the transmission device is optimized. The two motors can use motors with the same configuration, which effectively reduces the batch procurement cost. The first motor can replace the starter motor to start the engine, simplify the structure and reduce the cost. The engine can be directly driven, the power is directly output, and the transmission efficiency is high, which can achieve the best performance and fuel consumption to drive the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

FIG. 1 is a schematic diagram of a single-ring gear and double-planetary gear hybrid coupling structure in Embodiments 1 and 2 of the present invention.

FIG. 2 is a schematic diagram of power supply during on-site charging in Embodiments 1 and 2 of the present invention.

FIG3 is a schematic diagram of power supply during pure electric operation in Embodiments 1 and 2 of the present invention.

FIG. 4 is a schematic diagram of power supply during series-parallel operation in Embodiments 1 and 2 of the present invention.

FIG. 5 is a schematic diagram of power supply during direct drive operation in Embodiments 1 and 2 of the present invention.

FIG6 is a schematic diagram of power supply during energy recovery in Embodiments 1 and 2 of the present invention.

Among them, 1. engine, 2. torsional vibration damper, 3. input shaft, 4. first motor, 5. first sun gear, 6. first planetary gear, 7. first planetary carrier, 8. ring gear, 9. second planetary carrier, 10. second planetary gear, 11. second sun gear, 12. second motor, 13. output shaft, 14. differential, 15. wheel end.

DETAILED DESCRIPTION

Example 1

In a typical embodiment of the present invention, as shown in FIG. 1 to FIG. 6 , a single-ring gear and double-planetary gear hybrid power coupling structure is provided.

In the current dual-motor hybrid power system, physical energy storage is achieved by adding a flywheel energy storage system, thereby reducing the power of the dual motors. However, after adding the flywheel energy storage system, it is necessary to additionally arrange a clutch and brake adapted to the flywheel, which increases the complexity of the structure. In addition, the dual motors used still cannot achieve dual-motor power generation and dual-motor drive, and the motors are difficult to be effectively utilized, and the demand for the drive motor power is still high. Based on this, this embodiment provides a single-ring gear dual-planetary gear dual-motor hybrid power system drive device, which adopts a single-ring gear dual-planetary gear dual-motor structure. The engine 1 can drive the dual motors to charge at the same time, and the dual motors can drive the output shaft 13 simultaneously or separately to provide driving force, improve the output power in the pure electric drive state, and reduce the demand for motor power.

As shown in FIG1 , a single-ring gear and dual-planetary gear hybrid coupling structure includes an engine 1, a first planetary gear, a second planetary gear, a first motor 4 and a second motor 12. The engine 1 works in coordination with the first motor 4 and the second motor 12 to achieve switching between multiple operating states.

The first planetary row includes a first sun gear 5, a first planetary gear 6, a first planetary carrier 7 and a ring gear 8. The first planetary gear 6 is rotatably mounted on the first planetary carrier 7. The first sun gear 5 is coaxially distributed with the inner gear ring of the ring gear 8. One side of the first planetary gear 6 is meshed with the inner gear ring portion of the ring gear 8. The other side of the first planetary gear 6 is meshed with the first sun gear 5. The shaft of the first planetary carrier 7 is coaxially distributed with the ring gear 8. The second planetary row includes a second sun gear 11, a second planetary gear 10, a second planetary carrier 9 and a ring gear 8. The second planetary gear 10 is rotatably mounted on the second planetary carrier 9. The second sun gear 11 is coaxially distributed with the inner gear ring of the ring gear 8. One side of the second planetary gear 10 is meshed with the inner gear ring portion of the ring gear 8. The other side of the second planetary gear 10 is meshed with the second sun gear 11. The shaft of the second planetary carrier 9 is coaxially distributed with the ring gear 8. In this embodiment, the first planetary row and the second planetary row share the same ring gear 8 and mesh at different positions of the ring gear 8.

The output end of the engine 1 is connected to the first planetary carrier 7 through the input shaft 3, the input and output ends of the first motor 4 are connected to the first sun gear 5, the input and output ends of the second motor 12 are connected to the second sun gear 11, and the second planetary carrier 9 is connected to the output shaft 13, which can be connected to the wheel end 15 to provide power for the wheel end 15.

Among them, the first planetary row and the second planetary row share the same ring gear 8, a first inner ring gear is provided at one end of the ring gear 8, and a second inner ring gear is provided at the other end, the first planetary gear 6 is meshed with the first inner ring gear, and the second planetary gear 10 is meshed with the second inner ring gear, and other components of the first planetary gear except the ring gear 8 are isolated from other components of the second planetary gear except the ring gear 8.

Specifically, the perpendicular bisector of the axial midpoint of the gear ring 8 is used as the reference plane, and the first inner gear ring and the second inner gear ring are symmetrically arranged relative to the reference plane, and the first inner gear ring and the second inner gear ring rotate synchronously. After the first inner gear ring and the second inner gear ring are symmetrically arranged, the planetary gears, planet carriers and sun gears they match are also in corresponding positions.

The first motor 4 and the second motor 12 are both generator motors, which can not only meet the demand of output torque to drive the output shaft 13 during motor-assisted driving, but also meet the demand of power generation during kinetic energy recovery and engine 1 driving. As shown in Figures 2, 4 and 6, the first motor 4 and the second motor 12 transmit the generated electric energy to the power battery for storage. As shown in Figures 3 and 5, when the first motor 4 and the second motor 12 work externally and output torque, they draw electricity from the power battery.

The first motor 4 and the second motor 12 can be permanent magnet synchronous motors, which can be used as motors to convert electrical energy into mechanical energy, and can also be used as generators to convert mechanical energy into electrical energy; in other optional implementations, other forms of motors can also be used as the first motor 4 and the second motor 12. The first motor 4 can replace the starter motor to start the engine 1, simplifying the structure and reducing costs.

A torsional vibration damper 2 is connected between the input shaft 3 and the output end of the engine 1, and the output shaft 13 is connected to the wheel end 15 through the differential 14. The torsional vibration damper 2 is mainly composed of elastic elements and damping elements, etc., and reduces the torsional stiffness of the joint part between the crankshaft of the engine 1 and the transmission system, thereby reducing the natural frequency of torsional vibration of the transmission system. It helps to reduce the resonance phenomenon generated by the transmission system during operation and improve the stability and smoothness of the transmission. Increase the torsional damping of the transmission system and suppress the amplitude caused by torsional resonance. When the car turns, the differential 14 makes the left and right wheels roll at different speeds, thereby ensuring that the driving wheels on both sides perform pure rolling motion to prevent the tires from slipping on the ground.

Taking full advantage of the characteristics of the engine 1 and the motor, a symmetrical structure arrangement of a single gear ring, double planetary gears and double motors is adopted. The dual motors can be used for driving and power generation, and the dual motors can be driven simultaneously or separately as required, achieving parallel-parallel operation or hybrid operation, thereby improving the flexibility of hybrid power output.

Example 2

In another typical embodiment of the present invention, as shown in FIGS. 1 to 6 , a control method for a single-ring gear and double-planet gear hybrid coupling structure is provided, using a single-ring gear and double-planet gear hybrid coupling structure as in Example 1.

include:

During on-site charging, as shown in FIG2 , the engine 1 is engaged in the work, and the engine 1 drives the first motor 4 and the second motor 12 to generate electricity respectively, and the generated electricity is stored in the power battery;

During pure electric operation, as shown in FIG3 , the engine 1 does not participate in the work, and the first motor 4 and/or the second motor 12 work to drive the output shaft 13 to output;

During the hybrid operation, as shown in FIG4 , the engine 1 participates in the work, the engine 1 diverts the power to the first motor 4 for power generation and the output shaft 13 for output, and the second motor 12 works and cooperates with the motor to drive the output shaft 13;

During direct drive operation, as shown in FIG5 , the engine 1 works independently to drive the output shaft 13 to output, and the first motor 4 and the second motor 12 do not work;

During hybrid operation, the engine 1 participates in the work, and the engine 1, the first motor 4 and the second motor 12 work together to drive the output shaft 13;

During energy recovery, as shown in FIG6 , the engine 1 does not participate in the work, and the output shaft 13 reversely pulls the second motor 12 to generate electricity, and the generated electricity is stored in the power battery.

A control method for a single-ring gear and double-planetary gear hybrid coupling structure has multiple operating states, and controls a single-ring gear and double-planetary gear hybrid coupling structure to execute multiple working modes, corresponding to the realization of in-situ charging mode, pure electric mode, hybrid mode, direct drive mode, hybrid mode and energy recovery mode.

After the power reaches the output shaft 13 , it is distributed to the wheel ends 15 via the differential 14 .

As shown in FIG. 2 , when the power battery is low in power, it can be switched to the on-site charging mode to perform on-site charging, where the engine 1 drives the first motor 4 and the second motor 12 to generate electricity and store the electrical energy in the power battery.

Among them, in combination with Figure 1 and Figure 3, the pure electric mode can also be divided into a single-motor pure electric mode and a dual-motor pure electric mode according to the working status of the first motor 4 or the second motor 12.

When the single-motor pure electric mode is adopted, the engine 1 and the first motor 4 do not work, and the second motor 12 drives the output shaft 13 to drive the vehicle; or, the engine 1 and the second motor 12 do not work, and the first motor 4 drives the output shaft 13 to drive the vehicle.

When the dual-motor pure electric mode is adopted, as shown in Figure 3, the engine 1 is not working, the input shaft 3 and the first planetary carrier 7 connected to the input shaft 3 are locked, and the first motor 4 drives the ring gear 8 to operate through the first sun gear 5, thereby driving the second planetary gear 10 to move. At the same time, the second motor 12 drives the second planetary gear 10 to operate through the second sun gear 11, and together with the first motor 4, drives the output shaft 13 to operate through the second planetary carrier 9 to jointly drive the vehicle.

Specifically, when the pure electric mode is adopted, the working states of the first motor 4 and the second motor 12 can also be adjusted according to the motion state of the vehicle, including:

When the vehicle speed is not zero and is lower than a first set speed, obtaining the vehicle running state;

If the vehicle is in the acceleration state and executes the dual-motor pure electric mode, the first motor 4 and the second motor 12 work together to drive the output shaft 13; the dual motors are operated to increase the driving torque, and the speed of the output shaft 13 can be changed by changing the torque and speed of the two motors. The operation is convenient. When the vehicle starts or accelerates, the dual motors are used to output torque to the outside, which has strong explosive power, high motor power utilization, and good acceleration performance. At the same time, the power design requirements of the motors are reduced, thereby reducing costs;

If the vehicle is in a uniform speed state and executes the single-motor pure electric mode, the first motor 4 or the second motor 12 works to drive the output shaft 13; when the vehicle is in a low-speed uniform pure electric state, the required torque is relatively low, and the single-motor drive can meet the working condition requirements and effectively reduce the power loss;

If the vehicle is in a decelerating state, energy recovery is performed.

As shown in Figure 4, when the vehicle speed is not lower than the first set speed and not higher than the second set speed, the hybrid mode is adopted to perform hybrid operation. The engine 1 participates in the work and is in a working condition that meets the set fuel economy, driving the output shaft 13 to operate, and the second motor 12 serves as an auxiliary power, and after coupling the torque from the engine 1, it is transmitted to the output shaft 13 to drive the output shaft 13 to operate.

Specifically, the engine 1 is started and is in the best working state, a part of the torque is transmitted to the first motor 4 through the output shaft 13, the first planetary carrier 7, the first planetary gear 6, and the first sun gear 5 to generate electricity, and the other part of the torque is transmitted to the output shaft 13 through the output shaft 13, the first planetary carrier 7, the first planetary gear 6, the ring gear 8, the second planetary gear 10, and the second planetary carrier 9, and is distributed to the wheel end 15 through the differential 14. The torque of the second motor 12 is transmitted to the second planetary carrier 9 through the second sun gear 11 and the second planetary gear 10 connected thereto, and is coupled with the torque transmitted by the engine 1 and then transmitted to the output shaft 13 for output. Through the hybrid operation, the overall torque is improved, and it is ensured that the engine 1 is in the best working state to achieve fuel saving.

As shown in FIG. 5 and FIG. 6 , when the vehicle speed reaches a speed range where the fuel economy of the engine 1 is relatively high, the engine 1 can execute a direct drive mode or a hybrid mode to ensure the fuel economy and torque output of the engine 1 .

When the vehicle speed is higher than the second set speed, the vehicle running state is obtained.

If the vehicle is in the acceleration state, it switches to the hybrid mode and performs hybrid operation. The engine 1, the first motor 4 and the second motor 12 work together to drive the output shaft 13; the torque is transmitted to the output shaft 13 through the output shaft 13, the first planetary carrier 7, the first planetary gear 6, the ring gear 8, the second planetary gear 10 and the second planetary carrier 9, and is distributed to the wheel end 15 through the differential 14. The torque output by the first motor 4 is transmitted to the second planetary carrier 9 through the first sun gear 5, the first planetary gear 6 and the ring gear 8 connected thereto, and the torque of the second motor 12 is transmitted to the second planetary carrier 9 through the second sun gear 11 and the second planetary gear 10 connected thereto, and is coupled with the torque transmitted by the first motor 4 and transmitted to the output shaft 13 for output, and is distributed to the wheel end 15 through the differential 14; the first motor 4 and the second motor 12 run and output torque, which serves as auxiliary power to increase the torque of the output shaft 13 and provide sufficient power for the vehicle to overtake at high speed;

If the vehicle is in a constant speed state, it switches to the direct drive mode and performs direct drive operation. The engine 1 works to drive the output shaft 13. The torque is transmitted to the output shaft 13 through the output shaft 13, the first planetary carrier 7, the first planetary gear 6, the ring gear 8, the second planetary gear 10, and the second planetary carrier 9, and is distributed to the wheel end 15 through the differential 14. The first motor 4 and the second motor 12 are idling, and the torque of the engine 1 is directly transmitted to the output shaft 13 and distributed to the wheel end 15 through the differential 14. When the vehicle is running at high speed, the direct drive transmission efficiency of the engine 1 is high, and the fuel economy is high.

If the vehicle is in a decelerating state, it switches to energy recovery mode and performs energy recovery.

As shown in Figure 6, during the vehicle deceleration process, when the charge state of the vehicle battery does not exceed the upper limit of the battery charge state, the vehicle enters the energy recovery mode, and the torque is transmitted from the wheel end 15, the differential 14, the output shaft 13, the second planetary carrier 9, the second planetary gear 10, and the second sun gear 11 to the second motor 12. At this time, the second motor 12 generates electricity. On the one hand, the second motor 12 generates electricity and supplies it to the power battery for storage, which is then released to reduce the energy consumption of the vehicle. On the other hand, the second motor 12 can provide braking force to decelerate the vehicle.

In the case of emergency braking, part of the torque is transmitted from the wheel end 15, the differential 14, the output shaft 13, the second planetary carrier 9, the second planetary gear 10, and the second sun gear 11 to the second motor 12, and the other part of the torque is transmitted from the wheel end 15, the differential 14, the output shaft 13, the second planetary carrier 9, the second planetary gear 10, the ring gear 8, the first planetary gear 6, and the first sun gear 5 to the first motor 4. At this time, the first motor 4 and the second motor 12 generate electricity simultaneously, recover energy and provide greater braking force, so that the vehicle can decelerate quickly.

It can be understood that the first set speed and the second set speed in this embodiment can be selected and adjusted according to needs. The value of the second set speed is greater than the value of the first set speed. The first set speed can be 40km/h, 50km/h, etc., and the second set speed can be 90km/h, 100km/h, etc.

The combination of different modes and states of the three input terminals of the engine 1, the first motor 4 and the second motor 12 can produce a variety of different working modes. The first motor 4 and the second motor 12 can generate electricity and drive output. The pure electric dual-motor output mode has high motor power utilization and good acceleration performance. At the same time, it also reduces the design requirements of the motor and optimizes the layout of the transmission device. The two motors can use motors with the same configuration, effectively reducing the batch procurement cost, and the first motor 4 can replace the starter motor to start the engine 1, simplifying the structure and reducing costs. The engine 1 can be directly driven, the power is directly output, and the transmission efficiency is high, which can achieve optimal performance and fuel consumption to drive the vehicle.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (10)

1. A single-gear ring and double-planetary gear hybrid coupling structure, characterized in that it includes an engine, a first planetary gear, a second planetary gear, a first motor and a second motor, the first planetary gear includes a first sun gear, a first planetary gear, a first planetary gear and a ring gear, the second planetary gear includes a second sun gear, a second planetary gear, a second planetary gear and a ring gear, and the first planetary gear and the second planetary gear share the same ring gear; the output end of the engine is connected to the first planetary gear through an input shaft, the input and output ends of the first motor are connected to the first sun gear, the input and output ends of the second motor are connected to the second sun gear, and the second planetary gear is connected to the output shaft. 2. A single-gear ring and double-planetary gear hybrid coupling structure as described in claim 1, characterized in that a first inner gear ring is provided at one end of the gear ring and a second inner gear ring is provided at the other end, the first planetary gear is meshed with the first inner gear ring, and the second planetary gear is meshed with the second inner gear ring. 3. A single-ring gear and double-planetary gear hybrid coupling structure as described in claim 2, characterized in that the perpendicular bisector of the axial midpoint of the ring gear is used as a reference plane, the first inner ring gear and the second inner ring gear are symmetrically distributed relative to the reference plane, and the first inner ring gear and the second inner ring gear rotate synchronously. 4. A single-ring gear and double-planetary gear hybrid coupling structure as claimed in claim 1, characterized in that both the first motor and the second motor are generator motors. 5. A single-ring gear and double-planetary gear hybrid coupling structure as claimed in claim 1, characterized in that a torsional vibration damper is connected between the input shaft and the output end of the engine, and the output shaft is connected to the wheel end through a differential. 6. A control method for a single-gear-ring dual-planetary-gear hybrid coupling structure, applied to a single-gear-ring dual-planetary-gear hybrid coupling structure as claimed in any one of claims 1 to 5, characterized in that it comprises: When charging on the spot, the engine is involved in the work, the engine drives the first motor and the second motor to generate electricity respectively, and the generated electricity is stored in the power battery; During pure electric operation, the engine does not work, and the first motor and/or the second motor work to drive the output shaft for output; During hybrid operation, the engine participates in the work, and the engine diverts power to the first motor for power generation and output to the output shaft, while the second motor works and cooperates with the electric motor to drive the output shaft. 7. The control method of the single-gear-ring dual-planetary-gear hybrid coupling structure according to claim 6, characterized in that during direct drive operation, the engine works independently to drive the output shaft to output, and the first motor and the second motor do not work; During hybrid operation, the engine participates in the work, and the engine, the first motor and the second motor work together to drive the output shaft; During energy recovery, the engine does not participate in the work, the output shaft reversely drags the second motor to generate electricity, and the generated energy is stored in the power battery. 8. The control method of the single-ring gear and double-planet gear hybrid coupling structure according to claim 7, characterized in that when the vehicle speed is not zero and is lower than a first set speed, the vehicle running state is obtained; If the vehicle is in an accelerating state, the first motor and the second motor work together to drive the output shaft; If the vehicle is in a constant speed state, the first motor or the second motor works to drive the output shaft; If the vehicle is in a decelerating state, energy recovery is performed. 9. The control method of the single-ring gear and double-planetary gear hybrid coupling structure as described in claim 7 is characterized in that when the vehicle speed is not lower than a first set speed and not higher than a second set speed, a series-parallel operation is performed, the engine participates in the work and is in a working condition that meets the set fuel economy, the output shaft is driven to operate, and the second motor is used as an auxiliary power to assist in driving the output shaft to operate. 10. The control method of the single-ring gear double-planet gear hybrid coupling structure according to claim 7, characterized in that when the vehicle speed is higher than the second set speed, the vehicle running state is obtained, If the vehicle is in an accelerating state, a hybrid operation is performed, and the engine, the first motor and the second motor work together to drive the output shaft; If the vehicle is in a constant speed state, direct drive operation is performed, the engine works, and the output shaft is driven; If the vehicle is in a decelerating state, energy recovery is performed.