Electric automobile power transmission system and working mode thereof

Abstract

The invention relates to an electric vehicle power transmission system and a working mode thereof, an energy storage system is provided with an electromagnetic coupler and an energy storage flywheel, the electromagnetic coupler adopts a double-rotor motor, and is provided with an outer rotor shaft, an inner rotor shaft and an electrical terminal which are used for output and input; the outer rotor shaft is in driving connection with an energy storage brake wheel through a first transmission mechanism, the inner rotor shaft is in driving connection with an energy storage flywheel through a second transmission mechanism, the electrical terminal is connected with a battery through a battery management system, and a flywheel clutch is arranged between the inner rotor shaft and the second transmission mechanism. By controlling the working states of the flywheel clutch and the electromagnetic coupler, braking energy can be recycled in the form of mechanical energy and electric energy during deceleration, and a flywheel is used as a power source to assist in driving a rear wheel during acceleration under partial conditions. The two energy storage modes of flywheel energy storage and electrochemical energy storage are considered at the same time, and the method is suitable for rear wheel braking energy recovery of the front-wheel-driven pure electric vehicle.

Description

Technical Field

[0001] The present invention relates to an electric vehicle power transmission system and its working mode, and can be mainly used to realize the rear-wheel braking energy recovery of a front-wheel drive pure electric vehicle, belonging to the technical field of new energy vehicles and energy conservation. Background Art

[0002] The energy consumed by vehicle braking accounts for a high proportion of the total energy consumption, which not only wastes energy but also causes environmental problems. Especially in urban road conditions, the frequent deceleration-acceleration conditions of vehicles increase the average fuel consumption. Adopting the braking energy recovery technology to convert the energy consumed during vehicle braking into available energy and store it in a medium, and quickly release the energy when needed, is an effective means to reduce the energy consumption due to braking. For example, Chinese patent document CN114619865A discloses a hybrid power transmission system and a hybrid vehicle, including an engine, an intermediate shaft, a first transmission structure, a first motor and a second motor; the intermediate shaft is adapted to be connected to a load; the first transmission structure is drivingly connected to the intermediate shaft through a first on-off mechanism; the rotating shaft of the first motor is drivingly connected to the output shaft of the engine through a second transmission structure, and the first motor is adapted to be electrically connected to a power battery; the rotating shaft of the second motor is drivingly connected to the intermediate shaft through a third transmission structure, and the second motor is adapted to be electrically connected to a power battery; in the deceleration state, the load transmits power to the second motor through the intermediate shaft and the third transmission structure, causing the second motor to generate electricity. However, the current main energy storage methods include electrochemical energy storage and flywheel energy storage. Among them, electrochemical energy storage is widely used due to its high energy density, low price and mature technology, but its life is shortened due to frequent charge and discharge, and higher performance requirements are imposed on the electrochemical energy storage device; flywheel energy storage has the advantages of high efficiency, high instantaneous power, fast response and long cycle life, but its energy density is relatively low, and it is usually only suitable for energy requirements within a short period of time. Since it is difficult to integrate the two energy storage methods in practice, the current braking energy recovery and utilization technology adopts a single energy storage method and cannot better meet the actual needs. Summary of the Invention

[0003] The object of the present invention is to take into account the characteristics of electrochemical energy storage and flywheel energy storage to better meet the actual needs.

[0004] The technical solution of the present invention is as follows: For an electric vehicle power transmission system, an energy storage system is provided. The energy storage system is provided with an electromagnetic coupler and an energy storage flywheel. The electromagnetic coupler uses a dual-rotor motor, which is provided with an outer rotor shaft, an inner rotor shaft, and electrical terminals for outputting and inputting (used as output / input ports / interfaces). Among them, the outer rotor shaft and the inner rotor shaft are mechanical ports for mechanical output and input, and the electrical terminals are electrical ports for electrical energy output and input. The outer rotor shaft is drivingly connected to an energy storage brake wheel (a wheel / brake wheel in the vehicle that interacts due to connection with the energy storage system) through a first transmission mechanism (a connection method for realizing drive transmission). The inner rotor shaft is drivingly connected to the energy storage flywheel through a second transmission mechanism. The electrical terminals are connected to a battery through a battery management system. A flywheel clutch is provided between the inner rotor shaft and the second transmission mechanism.

[0005] The battery management system can adopt any suitable existing technology for battery charge and discharge management, and usually should be provided with an AC / DC circuit.

[0006] Preferably, both the first transmission mechanism and the second transmission mechanism are bidirectional transmission mechanisms so as to perform transmission in any direction according to actual needs, and generally, a gear transmission method can be adopted.

[0007] Furthermore, the energy storage system is provided with a clutch controller (or flywheel controller) for controlling the state of the flywheel clutch. The outputs of a flywheel speed sensor for real-time detection of the flywheel speed, an inner rotor speed sensor for real-time detection of the inner rotor, and an outer rotor speed sensor for real-time detection of the outer rotor speed are all connected to the clutch controller.

[0008] Preferably, the dual-rotor motor adopts a three-phase permanent magnet motor structure.

[0009] Preferably, the three-phase windings of the dual-rotor motor are arranged on the outer rotor. The electrical terminals are slip ring groups for connecting the three-phase windings. The slip ring group is composed of multiple slip rings corresponding to each winding and is arranged on the outer rotor shaft.

[0010] Furthermore, permanent magnets are provided on the inner rotor.

[0011] Preferably, the flywheel clutch adopts an electromagnetic clutch or a friction clutch.

[0012] Preferably, the energy storage brake wheel is the rear wheel, and the flywheel energy storage system is arranged on the rear axle of the vehicle.

[0013] Furthermore, the driving wheels of the vehicle are the front wheels. The drive system is placed in the front cabin and the front axle of the vehicle. The drive motor drives and connects the front wheels through a transmission, a main reducer, a differential, and a front wheel half shaft.

[0014] A rear-wheel clutch can be provided between the first transmission mechanism and the rear wheel (rear-wheel axle). When necessary (for example, during cruise control), the energy storage system can be disconnected through the rear-wheel clutch.

[0015] For any working mode of the electric vehicle power transmission system disclosed in the present invention, there are a flywheel energy recovery mode, a flywheel energy release mode, and a flywheel disconnection mode. In the flywheel energy recovery mode, the flywheel clutch is engaged. If the outer rotor speed is higher than the inner rotor speed, the electromagnetic coupler operates in the generator state, and the energy storage braking wheel is used as the power source to drive the flywheel to increase its speed for energy storage. The electric energy output of the outer rotor charges the battery. If the outer rotor speed is lower than the inner rotor speed, the electromagnetic coupler operates in the motor state, and the inner rotor speed increases (the inner rotor rotates relative to the outer rotor), driving the flywheel to increase its speed for energy storage. In the flywheel energy release mode, the flywheel clutch is engaged. If the inner rotor speed is higher than the outer rotor speed, the electromagnetic coupler operates in the generator state, and the flywheel is used as the power source to drive the energy storage braking wheel to increase its speed. The electric energy output of the outer rotor charges the battery. If the inner rotor speed is lower than the outer rotor speed, the electromagnetic coupler operates in the motor state, and the outer rotor speed increases (the outer rotor rotates relative to the inner rotor) to drive or assist in driving the energy storage braking wheel. In the flywheel disconnection mode, the flywheel clutch is in the disengaged state.

[0016] The switching of the working mode can be implemented according to the set control strategy. For example,

[0017] During deceleration (braking) (for example, after obtaining the brake pedal signal), based on the flywheel speed, inner rotor speed, and outer rotor speed obtained by each speed sensor, if the flywheel speed is zero or lower than the lower limit for driving the electromagnetic coupler (that is, if the real-time flywheel speed is transmitted to the inner rotor through the second transmission mechanism, and the real-time rear-wheel speed is transmitted to the outer rotor through the first transmission mechanism, the inner rotor speed will be lower than the outer rotor speed, and generally, it will be significantly lower than the outer rotor speed) and the flywheel clutch is in the disengaged state, control the flywheel clutch to engage (if there is a rear-wheel clutch and the rear-wheel clutch is in the disengaged state, also control the rear-wheel clutch to engage at the same time), so that the electromagnetic coupler operates in the generator state (the battery management system is in the battery charging state). Thus, the mechanical energy output (output from the inner rotor shaft) of the electromagnetic coupler drives the flywheel to increase its speed for energy storage, and the electric energy output of the electromagnetic coupler charges the battery for energy storage. When the flywheel speed is not lower than or higher than the lower limit for driving the electromagnetic coupler (for example, the real-time speed of the inner rotor is not lower than the real-time speed of the outer rotor), disengage the flywheel clutch, or, keep the flywheel clutch engaged and disengage the rear-wheel clutch (in the case of having a rear-wheel clutch), keep the electromagnetic coupler operating in the generator state, generate electricity with the flywheel as the power source, and the generated electric energy charges the battery for energy storage (the corresponding charging and energy storage can be controlled by the battery management system) until the flywheel rotor drops to the set lower speed limit in the corresponding situation.

[0018] During long-term normal driving, the flywheel clutch is restored to the disengaged state, and the rear-wheel clutch (if any) is in the disengaged or engaged state.

[0019] During acceleration (for example, after obtaining the throttle pedal / accelerator pedal signal), based on the flywheel speed, inner rotor speed, and outer rotor speed obtained by each speed sensor, if the flywheel speed is higher than the lower limit of the driving electromagnetic coupler (that is, if the real-time flywheel speed is transmitted to the inner rotor through the second transmission mechanism, and the real-time rear-wheel speed is transmitted to the outer rotor through the first transmission mechanism, the inner rotor speed will be higher than the outer rotor speed. For example, when starting after a temporary vehicle brake and the flywheel has a certain speed), control the engagement of the flywheel clutch (if there is a rear-wheel clutch and the rear-wheel clutch is in the disengaged state, also control the engagement of the rear-wheel clutch at the same time), so that the electromagnetic coupler operates in the generator state (the battery management system is in the battery charging state). Thus, the mechanical energy output (outer rotor shaft output) of the electromagnetic coupler is used as an auxiliary power source to drive the rear wheels to increase speed, and the electrical energy output of the electromagnetic coupler charges the battery for energy storage; when the flywheel speed is not higher than or lower than the lower limit of the driving electromagnetic coupler (for example, the real-time speed of the inner rotor is not higher than the real-time speed of the outer rotor), disengage the flywheel clutch and open the electrical port of the electromagnetic coupler, or, keep the flywheel clutch engaged and disengage the rear-wheel clutch (in the case of having a rear-wheel clutch), keep the electromagnetic coupler operating in the generator state, generate electricity using the flywheel as the power source, and the generated electrical energy charges the battery for energy storage (the corresponding charging and energy storage can be controlled by the battery management system) until the flywheel rotor drops to the set speed lower limit in the corresponding situation.

[0020] The beneficial effects of the present invention are as follows: Through different working states of the flywheel clutch and the electromagnetic coupler, it is possible to control the storage or release of energy of the flywheel according to actual needs. At the same time, the electrical energy generated when the electromagnetic coupler is used as a generator can be stored in the driving battery or other energy storage batteries, thereby realizing the conversion and storage of braking energy during the deceleration and braking process, and taking into account both chemical energy storage and mechanical energy storage methods; By using the front wheels of the vehicle as the driving wheels and the rear wheels as the energy storage braking wheels, the driving system and the energy storage system are respectively arranged in different positions, which facilitates the setting of the energy storage system on the vehicle, avoids or reduces excessive space occupation or interference with the layout of other devices due to the setting of the energy storage system, and at the same time is beneficial to simplifying and facilitating the driving connection between the energy storage system and the energy storage braking wheel; Since an AC permanent magnet double-rotor motor is used as the electromagnetic coupler, it has a fast response speed, high energy conversion utilization rate, and is beneficial to reducing the volume of the electromagnetic coupler. Brief Description of the Drawings

[0021] Figure 1 It is a schematic diagram of the structure of the power transmission system of the present invention;

[0022] Figure 2This is the electrical port characteristic diagram of the electromagnetic coupler of the present invention. The upper and lower diagrams on the left are the corresponding characteristic curves, and the schematic diagram of the basic structure of the electromagnetic coupler is on the right;

[0023] Figures 3 - 5 This is the schematic diagram of energy transfer and energy distribution in the flywheel energy recovery mode of the present invention, where Figure 3 is ω mo >ω mi in the case of, Figure 4 is ω mo <ω mi in the case of, Figure 5 is ω mo =ω mi in the case of. The left side of each figure is the schematic diagram of energy transfer, and the right side is the schematic diagram of energy distribution;

[0024] Figures 6 - 8 This is the schematic diagram of energy transfer and energy distribution in the flywheel energy release mode of the present invention, where Figure 6 is ω mo <ω mi in the case of, Figure 7 is ω mo >ω mi in the case of, Figure 8 is ω mo =ω mi in the case of. The left side of each figure is the schematic diagram of energy transfer, and the right side is the schematic diagram of energy distribution.

[0025] Markings in the figure: 1, front wheel; 2, half shaft; 3, main reducer; 4, rear wheel; 5, first transmission mechanism; 6, electromagnetic coupler; 6-1, outer rotor shaft; 6-2, inner rotor shaft; 6-3, slip ring; 7, second transmission mechanism; 8, energy storage flywheel; 9, outer rotor speed sensor; 10, inner rotor speed sensor; 11, flywheel clutch. Detailed implementation manners

[0026] See Figures 1 to 8, the energy storage system (or flywheel energy storage device) of this electric vehicle power transmission system is arranged on the rear axle of the vehicle, including a first transmission mechanism (referred to as the first transmission for short) 5, an electromagnetic coupler 6, an outer rotor shaft (the first mechanical port) 6-1, an inner rotor shaft (the second mechanical port) 6-2, a slip ring (electrical port) 6-3, a second transmission mechanism (referred to as the second transmission for short) 7, a flywheel (energy storage flywheel) 8, an outer rotor speed sensor 9, an inner rotor speed sensor 10, a flywheel clutch (referred to as the clutch for short) 11, and an energy storage battery (for example, a drive battery). The rear wheels are connected to the outer rotor shaft 6-1 of the electromagnetic coupler 6 through the first transmission 5. The inner rotor shaft 6-2 is connected to the flywheel 8 through the second transmission 8. The electrical port of the electromagnetic coupler (a slip ring can be used) is connected to the drive battery (or energy storage battery) through a charging and discharging circuit (or battery management system, equipped with an AC / DC circuit). When the electromagnetic coupler is in the power generation state (i.e., working in the generator mode), its electrical energy output is connected to the AC / DC through the electrical port and is used to charge the battery. When the electromagnetic coupler is in the electric state (i.e., working in the motor mode), the battery serves as the power source, and the electrical energy released by it is connected to the electromagnetic coupler through the AC / DC and the electrical port. The conventional drive system is placed in the front cabin and the front axle of the vehicle. The drive motor is connected to the main reducer 3 through a transmission. The main reducer drives the half shaft 2 to rotate, and then drives the front wheels 1 to rotate.

[0027] The electromagnetic coupler 6 uses a dual-rotor motor and is provided with three output / input ports (or interfaces). These three output / input ports are the first mechanical port (or the first mechanical port), the second mechanical port (or the second mechanical port), and the electrical port (or the electrical port). The first mechanical port is the outer rotor shaft 6-1, the second mechanical port is the inner rotor shaft 6-2, and the electrical port is the slip ring 6-3 arranged on the outer rotor shaft. The working principle of the dual-rotor motor is similar to that of a permanent magnet synchronous motor. Therefore, this dual-rotor motor can be regarded as a permanent magnet synchronous motor with a rotatable stator. The electromagnetic coupler is arranged between the flywheel and the rear wheels. When the vehicle decelerates, the clutch engages, and the kinetic energy transmitted by the vehicle's rear wheels is increased in speed through two-stage gear transmission pairs and stored in the flywheel. When accelerating, the energy of the flywheel is released to meet the performance requirements of the vehicle drive system. The electrical energy generated by the electromagnetic coupler during power generation is stored in the vehicle's power battery or energy storage battery. When necessary, the electromagnetic coupler can also work in the motor state as an auxiliary power source. The existing vehicle processing and control device can be used, with the support of software, as the controller of the energy storage device. An independent controller of the energy storage device can also be set to receive the real-time detection information of each sensor, as well as the braking information (for example, the brake pedal signal) and acceleration information (for example, the accelerator pedal signal) of the vehicle, and accordingly control the engagement and disengagement state of the flywheel clutch. The setting methods of the inner rotor speed sensor 10, the outer rotor speed sensor 9, and the clutch 11 can be based on the prior art. A flywheel rotation sensor can be set according to the prior art to obtain the real-time speed of the flywheel.

[0028] Electromagnetic coupling drive is a non-contact torque transmission method. The electromagnetic coupler can essentially be regarded as an AC motor with both a stator and a rotor that can rotate, that is, a dual-rotor motor. It has three-phase windings on its outer rotor, and permanent magnets are arranged on the inner rotor. Two mechanical ports are respectively connected to the corresponding transmission mechanisms to connect the vehicle (rear-wheel system) and the flywheel. The electrical port is connected to the battery through AC / DC. The clutch turntable of the flywheel is controlled by a controller, and the on-off of the circuit between the electrical port and the AC / DC circuit (or the battery) can be controlled. When it is disconnected, the electrical port can be regarded as an open circuit.

[0029] According to the law of conservation of energy, when the inner rotor drives the flywheel to rotate (accelerate), the mechanical energy output by the inner rotor = the mechanical energy input by the outer rotor + the electrical energy input by the controller - the losses between the inner and outer rotors. Since the controller is mainly used to handle the difference in mechanical power, the capacity of the controller can be relatively small, about 15% of the capacity of the synchronous generator.

[0030] The electromagnetic coupler is determined to be in the power generation state or the electric state by the rotational speed signals of the inner and outer rotors collected by the rotational speed sensors of the inner and outer rotors and the signals of the vehicle's accelerator pedal and brake pedal. According to the real-time rotational speed of the flywheel, when the vehicle decelerates, by controlling the clutch to engage, the kinetic energy transmitted by the vehicle's rear wheels can drive the flywheel to increase in speed after being increased by two-stage gear transmission pairs, and the energy is stored in the flywheel. At the same time, the generated electrical energy is stored in the battery; when the vehicle needs to accelerate, the flywheel serves as an auxiliary power source to release energy to meet the performance requirements of the vehicle drive system. During the above energy recovery and release process, the conversion of kinetic energy between the vehicle (rear wheel) and the flywheel is achieved by controlling the electromagnetic coupler. The electromagnetic coupler can be appropriately set so that the conversion amount of electrical energy is much smaller than the total energy in the mechanical energy conversion process.

[0031] To quantitatively describe the characteristics of the electromagnetic coupling type braking energy recovery system, the mechanical angular velocities of the inner rotor and the outer rotor are defined as ω mi 、ω mo , the slip mechanical angular velocity and slip power are ω m 、P S , and the rated angular velocity, rated power, and rated torque of the electromagnetic coupler are ω N 、P N 、T N . The angular velocity, torque, and power in the electromagnetic coupler satisfy the following relationships:

[0032]

[0033] Assume that the electromagnetic coupler operates at the rated torque and satisfies ω mi =kω N ,ω mo =(k +

[0034] 1) ω N where \(k\geq0\). If the influence of the moment of inertia of the inner and outer rotors and the viscous friction coefficient is not considered, the input power \(P\) of the coupler at this time o , output power \(P\) i , slip power, and slip angular velocity satisfy the following formula:

[0035]

[0036] Table 1 shows the values of the mechanical port power, torque, and speed of the electromagnetic coupler when \(k\) takes 0, 1.0, and 1.5.

[0037] Table 1. Mechanical port power of the electromagnetic coupler under different \(k\) values

[0038]

[0039] When \(k = 0\), the inner rotor is fixed, and the electromagnetic coupler is equivalent to an ordinary motor; when \(k>0\), the inner rotor is released from fixation, and the electromagnetic coupler is equivalent to a dual-mechanical-port motor. Due to the rotation of the inner rotor shaft, the induced voltage on the winding decreases. At this time, the torque-speed characteristic of the coupler shifts to the right, as Figure 2 shown.

[0040] Although the electric drive system has good acceleration performance at low speeds, there is a problem of insufficient driving torque when working in the constant power region at high speeds; on the other hand, when a traditional electric vehicle brakes at high speeds, the motor regenerative braking force will be limited by the available output torque of the motor. As can be seen from the \(T-\omega\) characteristic of the electrical port of the electromagnetic coupler in Figure 2 , the electromagnetic coupling type braking energy recovery system can exert the maximum torque in different speed ranges, that is, the operating point of the system changes and moves towards the high-speed region.

[0041] According to formula (2), when the electromagnetic coupling type braking energy recovery system operates at the rated torque, the power that can be transmitted by the mechanical port is much greater than its rated power. The power recovered by the flywheel from the wheels is not affected by the rated power of the motor and power electronic equipment, and the energy is directly stored in the form of mechanical energy. The battery only needs to recover the slip power in the form of electrochemical energy.

[0042] According to actual needs, the working mode of the energy storage system can be controlled. According to the energy change mode of the flywheel, it can be divided into the flywheel energy recovery (abbreviated as energy recovery) mode or the flywheel energy release (abbreviated as energy release) mode:

[0043] 1. Flywheel energy recovery mode

[0044] For example, when the vehicle decelerates (applies the brakes), the clutch 11 engages, and the rear wheels 4 of the vehicle drive the electromagnetic outer rotor shaft 6-1 to rotate via the first transmission mechanism (usually a gear transmission mechanism, or gear pair) 5. The inner rotor shaft 6-2 is speeded up via the second transmission mechanism (usually a gear transmission mechanism, or gear pair) 7 and stored in the flywheel.

[0045] To quantitatively illustrate the magnitude of the energy conversion during vehicle deceleration, assume that the active power transmitted to the outer rotor shaft via the first transmission mechanism is P o , and after deducting the iron loss P Fe of the outer rotor, the electromagnetic power transmitted to the inner rotor of the electromagnetic coupler through the air gap is P em . The electromagnetic power is divided into mechanical power P emch and slip power P s in the inner rotor, and the following equation is satisfied:

[0046]

[0047] In the formula, s is the slip ratio.

[0048] The mechanical power P emch in the inner rotor is output to the input shaft of the second transmission after deducting the mechanical loss P ml . At this time, the active power on the inner rotor shaft is P i ; the slip power P s can be stored in the battery after being inverted by the controller (with a loss of P el ) after deducting the copper loss and stray loss P bl of the inner rotor winding.

[0049] The specific working mode in the energy recovery mode can be controlled according to the actual working conditions and control strategy of the vehicle. For example:

[0050] Figure 3 shows a working mode and the corresponding energy conversion process when the angular velocity of the outer rotor shaft is greater than that of the inner rotor shaft. The mechanical power P emch of the inner rotor shaft is stored in the flywheel via the second transmission, and the slip power P s is stored in the battery after being inverted by AC / DC. At this time, the electromagnetic coupler acts as a generator;

[0051] Figure 4 shows a working mode and the corresponding energy conversion process when the angular velocity of the outer rotor shaft is less than that of the inner rotor shaft. In this state, according to actual needs, the battery can be used as a power source to speed up the flywheel through the electromagnetic coupler. At this time, the electromagnetic coupler acts as a motor;

[0052] Figure 5It shows a working mode when the inner and outer rotors have the same speed and the corresponding energy conversion process. At this time, the slip power is zero. Under certain working condition changes, it can be regarded that the mechanical power on the outer rotor shaft is directly transmitted to the flywheel through the two mechanical ports of the electromagnetic coupler.

[0053] 2. Flywheel energy release mode

[0054] For example, in the acceleration state, the clutch 11 is engaged, and the energy stored in the flywheel acts on the rear wheel through the second transmission, clutch, inner rotor shaft, outer rotor shaft and the first transmission mechanism as an auxiliary power source.

[0055] The specific working mode in the energy release mode can be controlled according to the actual working conditions and control strategies of the vehicle. For example:

[0056] Figure 6 It shows a working mode when the angular velocity of the inner rotor shaft is greater than that of the outer rotor shaft and the corresponding energy conversion process. The mechanical power P of the electromagnetic coupler emch acts on the rear wheel after being decelerated by the first transmission mechanism, and the slip power P s is stored in the battery after being inverted by the controller. At this time, the electromagnetic coupler is equivalent to a generator;

[0057] Figure 7 It shows a working mode when the angular velocity of the inner rotor shaft is less than that of the outer rotor shaft and the corresponding energy conversion process. The battery can supply energy to the wheels through the electromagnetic coupler. At this time, the electromagnetic coupler is equivalent to a motor; it can also cut off the connection with the energy storage braking wheel (for example, the rear wheel) through the wheel clutch arranged between the first transmission mechanism and the energy storage braking wheel.

[0058] Figure 8 It shows a working mode when the inner and outer rotors have the same speed and the corresponding energy conversion process. The slip power of the electromagnetic coupler is zero. Under certain working condition changes, it can be regarded that the mechanical energy in the flywheel drives the rear wheel through the two mechanical ports of the electromagnetic coupler.

[0059] The energy exchange in the two modes is shown in Table 2:

[0060] Table 2. Examples of the working mode of the electromagnetic coupler and the energy exchange relationship in the two modes

[0061]

[0062]

[0063] In the table, "-" represents meaningless.

[0064] All the preferred and optional technical means disclosed in the present invention can be arbitrarily combined to form several different specific embodiments, unless otherwise specified or one preferred or optional technical means further limits another technical means.

Claims

1. An electric vehicle power transmission system is provided with an energy storage system, characterized in that The energy storage system is provided with an electromagnetic coupler and an energy storage flywheel. The electromagnetic coupler uses a dual-rotor motor, which is provided with an outer rotor shaft, an inner rotor shaft, and electrical terminals for output and input. The outer rotor shaft is drivingly connected to an energy storage brake wheel through a first transmission mechanism. The inner rotor shaft is drivingly connected to the energy storage flywheel through a second transmission mechanism. The electrical terminals are connected to a battery through a battery management system. A flywheel clutch is provided between the inner rotor shaft and the second transmission mechanism.

2. The electric vehicle power transmission system according to claim 1, wherein Both the first transmission mechanism and the second transmission mechanism are bidirectional transmission mechanisms.

3. The electric vehicle power transmission system according to claim 1, characterized in that The energy storage system is provided with a clutch controller for controlling the state of the flywheel clutch. The outputs of a flywheel speed sensor for real-time detection of the flywheel speed, an inner rotor speed sensor for real-time detection of the inner rotor, and an outer rotor speed sensor for real-time detection of the outer rotor speed are all connected to the clutch controller.

4. The electric vehicle power transmission system according to claim 1, wherein The dual-rotor motor adopts a three-phase permanent magnet motor structure.

5. The electric vehicle power transmission system according to claim 4, characterized in that The three-phase windings of the dual-rotor motor are arranged on the outer rotor. The electrical terminals are slip ring groups for connecting the three-phase windings. The slip ring groups are composed of multiple slip rings corresponding to each winding respectively and are arranged on the outer rotor shaft.

6. The electric vehicle power transmission system according to claim 5, characterized in that Permanent magnets are provided on the inner rotor.

7. The electric vehicle power transmission system according to claim 1, wherein The flywheel clutch adopts an electromagnetic clutch or a friction clutch.

8. The electric vehicle power transmission system according to claim 1, characterized in that The energy storage brake wheel is a rear wheel, and the flywheel energy storage system is arranged on the rear axle of the vehicle.

9. The electric vehicle power transmission system according to claim 8, wherein The driving wheels of the vehicle are front wheels. The drive system is placed in the front cabin and front axle of the vehicle. The drive motor drives and connects the front wheels through a transmission, a main reducer, a differential, and a front wheel half shaft.

10. The working mode of the electric vehicle power transmission system according to any one of claims 1-9, characterized in that There are a flywheel energy recovery mode, a flywheel energy release mode, and a flywheel cut-off mode. In the flywheel energy recovery mode, the flywheel clutch is engaged. If the outer rotor speed is higher than the inner rotor speed, the electromagnetic coupler operates in the generator state, and the energy storage brake wheel is used as the power source to drive the flywheel to increase its speed for energy storage. The electrical energy output of the outer rotor charges the battery. If the outer rotor speed is lower than the inner rotor speed, the electromagnetic coupler operates in the motor state, and the inner rotor speed increases, driving the flywheel to increase its speed for energy storage. In the flywheel energy release mode, the flywheel clutch is engaged. If the inner rotor speed is higher than the outer rotor speed, the electromagnetic coupler operates in the generator state, and the flywheel is used as the power source to drive the energy storage brake wheel to increase its speed. The electrical energy output of the outer rotor charges the battery. If the inner rotor speed is lower than the outer rotor speed, the electromagnetic coupler operates in the motor state, and the outer rotor speed increases, which is used to drive or assist in driving the energy storage brake wheel. In the flywheel cut-off mode, the flywheel clutch is in the disengaged state.

Images