Rear wheel braking energy recovery system suitable for front-drive electric automobile

Abstract

The utility model relates to a rear wheel braking energy recovery system suitable for a front-drive electric automobile, which 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 a rear wheel through a first transmission mechanism, and the inner rotor shaft is in driving connection with the rear wheel through a second transmission mechanism. The inner rotor shaft is in driving connection with the 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. A rear wheel clutch is arranged between the first transmission mechanism and the outer rotor shaft or between the first transmission mechanism and the rear wheel shaft. The energy storage device integrates two energy storage modes of flywheel energy storage and electrochemical energy storage, and is suitable for rear wheel braking energy recovery of the front-wheel-driven pure electric vehicle.

Description

TECHNICAL FIELD

[0001] The utility model relates to the rear wheel braking energy recovery system suitable for front drive electric automobile mainly can be used to realize rear wheel braking energy recovery of front wheel drive pure electric automobile, belong to new energy automobile and energy saving technical field. BACKGROUND

[0002] The energy consumed by the vehicle due to braking accounts for a high proportion in the total energy consumption, not only wasting energy, but also causing environmental problems, especially the frequent deceleration-acceleration working condition of the automobile under the urban road working condition increases the average fuel consumption. Adopting the braking energy recovery technology, the energy consumed by the vehicle during braking is converted into usable energy, and stored in the medium, which can be quickly released when used, which 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 hybrid electric vehicle, comprising an engine, an intermediate shaft, a first transmission structure, a first motor and a second motor; the intermediate shaft is adapted to be connected with the load; the first transmission structure is in transmission connection with the intermediate shaft through a first on-off mechanism; the rotating shaft of the first motor is in transmission connection with the output shaft of the engine through a second transmission structure, and the first motor is adapted to be electrically connected with the power battery; the rotating shaft of the second motor is in transmission connection with the intermediate shaft through a third transmission structure, and the second motor is adapted to be electrically connected with the power battery; in the deceleration state, the load transmits power to the second motor through the intermediate shaft and the third transmission structure, so that the second motor generates electricity. However, the current main energy storage methods include electrochemical energy storage and flywheel energy storage, among which electrochemical energy storage is widely used due to its high energy density, low price and mature technology, but frequent charging and discharging shortens its service life, and the performance requirement of electrochemical energy storage is relatively high; flywheel energy storage has the advantages of high efficiency, high instantaneous power, fast response and long cycle life, but the energy density is relatively low, and it is usually only suitable for energy demand within a short period of time. Due to the difficulty in combining the two energy storage methods in practice, the current braking energy recovery technology adopts a single energy storage method, which cannot better meet the actual demand. SUMMARY

[0003] The utility model has the purposes of taking into account the characteristics of electrochemical energy storage and flywheel energy storage, and better meeting the actual demand.

[0004] The utility model discloses a technical scheme is: be suitable for the rear wheel braking energy recovery system of front -drive electric automobile, be equipped with electromagnetic coupler and energy storage flywheel, electromagnetic coupler adopts double rotor motor, is equipped with the outer rotor shaft, inner rotor shaft and electrical terminal for output input ( be used as output input port / interface), wherein the outer rotor shaft and inner rotor shaft are mechanical port, and the output input for mechanical action, and the electrical terminal is electrical port, and the output for electric energy, the outer rotor shaft passes through first transmission mechanism and is connected with rear wheel drive ( for realizing the connection mode of drive transmission), the inner rotor shaft passes through second transmission mechanism and is connected with energy storage flywheel drive, the electrical terminal passes through battery management system and connects battery, be equipped with flywheel clutch between the inner rotor shaft and second transmission mechanism, be equipped with rear wheel clutch between first transmission mechanism and the outer rotor shaft or first transmission mechanism and rear wheel shaft.

[0005] Battery management system can adopt any suitable prior art for charge and discharge management of battery, and generally should be equipped with AC / DC circuit.

[0006] Preferably, the first transmission mechanism and the second transmission mechanism are both bidirectional transmission mechanisms, so as to transmit in either direction according to actual needs, and generally can adopt gear transmission mode.

[0007] Preferably, a flywheel speed sensor for real-time detection of flywheel speed is arranged, and the output of the flywheel speed sensor is connected to a controller for controlling the state of the flywheel clutch and the rear wheel clutch device.

[0008] Preferably, an outer rotor speed sensor for real-time detection of outer rotor speed is arranged, and the output of the outer rotor speed sensor is connected to the controller for controlling the state of the flywheel clutch and the rear wheel clutch device.

[0009] Preferably, an inner rotor speed sensor for real-time detection of inner rotor speed is arranged, and the output of the inner rotor speed sensor is connected to the controller for controlling the state of the flywheel clutch and the rear wheel clutch device.

[0010] Preferably, the double rotor motor adopts a three-phase permanent magnet motor structure.

[0011] Preferably, the three-phase windings of the double rotor motor are arranged on the outer rotor, and the electrical terminal is a slip ring group for connecting the three-phase windings, which is composed of a plurality of slip rings corresponding to each winding and arranged on the outer rotor shaft.

[0012] Further, the inner rotor is provided with permanent magnets.

[0013] Preferably, the flywheel clutch adopts an electromagnetic clutch or a friction clutch.

[0014] Preferably, the rear wheel clutch is an electromagnetic clutch or a friction clutch.

[0015] The recovery system can be arranged on a rear axle of the vehicle.

[0016] Further, the driving wheels of the vehicle are front wheels, the driving system is arranged in the front compartment and the front axle, and the driving motor is connected to the front wheels through a transmission, a main reducer, a differential and a front wheel half shaft.

[0017] The utility model can be in different working modes, such as a flywheel energy recovery mode, a flywheel energy release mode, a flywheel cutting mode or a system cutting mode, by controlling the state of each clutch and electromagnetic coupler. For example, in the flywheel energy recovery mode, the flywheel clutch is combined, and if the speed of the outer rotor is higher than that of the inner rotor, the electromagnetic coupler works in the generator state, and the flywheel is driven by the rear wheels to increase the speed and store energy, and the electric energy output of the outer rotor is used to charge the battery; if the speed of the outer rotor is lower than that of the inner rotor, the electromagnetic coupler works in the motor state, and the speed of the inner rotor increases (the inner rotor rotates relative to the outer rotor), driving the flywheel to increase the speed and store energy. In the flywheel energy release mode, the flywheel clutch is combined, and if the speed of the inner rotor is higher than that of the outer rotor, the electromagnetic coupler works in the generator state, and the flywheel is used as a power source to drive the rear wheels to increase the speed, and the electric energy output of the outer rotor is used to charge the battery; if the speed of the inner rotor is lower than that of the outer rotor, the electromagnetic coupler works in the motor state, and the speed of the outer rotor increases (the outer rotor rotates relative to the inner rotor), which is used to drive or assist in driving the rear wheels. In the flywheel cutting mode, the flywheel clutch is in a separated state. In the system cutting mode, the rear wheel clutch is separated, so that the recovery system is disconnected from the rear wheels.

[0018] The working mode of the utility model can be controlled or switched according to existing technologies or other appropriate technologies or control strategies. For example,

[0019] When decelerating (e.g. upon receiving a brake pedal signal), the flywheel speed, the inner rotor speed and the outer rotor speed are obtained by the respective speed sensors, and if the flywheel speed is zero or lower than the lower limit of driving the electromagnetic coupler (e.g. if the flywheel speed is transmitted to the inner rotor by the second transmission mechanism and the rear wheel speed is transmitted to the outer rotor by the first transmission mechanism, the inner rotor speed will be lower than the outer rotor speed, and in most cases, significantly lower than the outer rotor speed) and the flywheel clutch is in the disengaged state, the flywheel clutch is engaged (and the rear wheel clutch is also engaged if the rear wheel clutch is provided and is in the disengaged state), and the electromagnetic coupler is operated in the generator state (the battery management system is in the battery charging state), so that the mechanical energy output (the inner rotor shaft output) of the electromagnetic coupler drives the flywheel to increase the speed and store energy, and the electrical energy output of the electromagnetic coupler charges the battery to store energy; when the flywheel speed is not lower than or higher than the lower limit of driving the electromagnetic coupler (e.g. the real-time speed of the inner rotor is not lower than the real-time speed of the outer rotor), the flywheel clutch is disengaged, or the flywheel clutch is kept engaged and the rear wheel clutch is disengaged (if the rear wheel clutch is provided), and the electromagnetic coupler is kept in the generator state, and the flywheel is used as a power source to generate electricity, and the generated electrical energy is used to charge the battery to store energy (the corresponding charging energy can be controlled by the battery management system), until the flywheel rotor is reduced to the lower limit of the set speed under the corresponding condition.

[0020] During long-time normal driving, the flywheel clutch is returned to the disengaged state, and the rear wheel clutch (if provided) is in the disengaged state or the engaged state.

[0021] When accelerating (for example, after obtaining an accelerator pedal signal), the flywheel speed, the inner rotor speed and the outer rotor speed are obtained according to each speed sensor, and when the flywheel speed is higher than the lower limit of driving the electromagnetic coupler (for example, when the flywheel has a certain speed after the vehicle temporarily brakes and starts, and the flywheel speed is transmitted to the inner rotor through the second transmission mechanism, and the 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), the flywheel clutch is controlled to be combined (and the rear wheel clutch is also controlled to be combined when the rear wheel clutch is in a separated state), the electromagnetic coupler works in the generator state (the battery management system is in the battery charging state), the mechanical energy output (the outer rotor shaft output) of the electromagnetic coupler is used as an auxiliary power source to drive the rear wheel to increase speed, and the electrical energy output of the electromagnetic coupler charges the battery to store energy; when the flywheel speed is not higher than or lower than the lower limit of driving the electromagnetic coupler (for example, the real-time speed of the inner rotor is not higher than the real-time speed of the outer rotor), the flywheel clutch is separated, the electrical port of the electromagnetic coupler is opened, or the flywheel clutch is combined and the rear wheel clutch is separated (in the case of the rear wheel clutch), the electromagnetic coupler works in the generator state, the flywheel is used as a power source to generate electricity, and the generated electrical energy charges the battery to store energy (the corresponding charging and energy storage can be controlled by the battery management system), until the flywheel rotor is reduced to the set lower limit speed.

[0022] The flywheel clutch, the rear wheel clutch and the electromagnetic coupler are arranged, the electromagnetic coupler can work in two different states of the generator and the motor, the two mechanical ports of the outer rotor shaft and the inner rotor shaft and the electrical port of the slip ring group are arranged, the different working states of the clutches and the electromagnetic coupler can be controlled, the flywheel can store energy or release energy according to actual needs, the electrical energy generated when the electromagnetic coupler is used as the generator can be stored in the driving battery or other energy storage batteries, the conversion and storage of braking energy can be realized during the deceleration and braking process, the chemical energy storage and the mechanical energy storage are combined, the front wheels of the vehicle are used as driving wheels, and the rear wheels are used as energy storage braking wheels for implementing the braking energy recovery, the driving system and the energy recovery system are arranged at different positions, the arrangement of the system on the vehicle is facilitated, the space occupied by the system is reduced, the arrangement of other devices is avoided or reduced, the driving connection between the system and the rear wheels is facilitated, the AC permanent magnet double-rotor motor is used as the electromagnetic coupler, the response speed is high, the energy conversion utilization rate is high, and the size of the electromagnetic coupler is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The utility model discloses a structure schematic diagram of the utility model and vehicle conventional transmission system;

[0024] Figure 2The left upper and lower graphs of the electrical port characteristic diagram of the electromagnetic coupler are corresponding characteristic curves, and the right side is a basic structure schematic diagram of the electromagnetic coupler;

[0025] Figures 3-5 The utility model discloses an energy transmission and energy distribution schematic diagram when working in flywheel energy recovery mode, wherein Figure 3 For the case of ω mo > ω mi , Figure 4 For the case of ω mo < ω mi , Figure 5 For the case of ω mo = ω mi , the left side in each graph is an energy transmission schematic diagram, and the right side is an energy distribution schematic diagram.

[0026] Figures 6-8 The utility model discloses an energy transmission and energy distribution schematic diagram when working in flywheel energy release mode, wherein Figure 6 For the case of ω mo < ω mi , Figure 7 For the case of ω mo > ω mi , Figure 8 For the case of ω mo = ω mi , the left side in each graph is an energy transmission schematic diagram, and the right side is an energy distribution schematic diagram.

[0027] Mark in the drawing: 1, front wheel;2, half axle;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 DESCRIPTION

[0028] Referring to Figures 1 to 8This regenerative braking system can be installed on the rear axle of a vehicle and includes a first transmission mechanism (hereinafter referred to as the first transmission) 5, an electromagnetic coupler 6, an outer rotor shaft (first mechanical port) 6-1, an inner rotor shaft (second mechanical port) 6-2, a slip ring (electrical port) 6-3, a second transmission mechanism (hereinafter referred to as the second transmission) 7, a flywheel (energy storage flywheel) 8, an outer rotor speed sensor 9, an inner rotor speed sensor 10, a flywheel clutch (hereinafter referred to as the clutch) 11, a rear wheel clutch, and an energy storage battery (e.g., a drive battery). The rear wheel clutch (not shown) can be located between the first transmission mechanism and the outer rotor shaft, or between the first transmission mechanism and the rear wheel clutch. Between the wheel axles, the rear wheel is connected to the outer rotor shaft 6-1 of the electromagnetic coupler 6 via the first transmission 5, and the inner rotor shaft 6-2 is connected to the flywheel 8 via the second transmission 8. The electrical port (which may use a slip ring) of the electromagnetic coupler is connected to the drive battery (or energy storage battery) via a charging and discharging circuit (or battery management system, equipped with an AC / DC circuit). When the electromagnetic coupler is in generator mode (i.e., operating in generator mode), its electrical energy output is connected to the AC / DC converter via the electrical port to charge the battery. When the electromagnetic coupler is in electric mode (i.e., operating in motor mode), the battery acts as a power source, and its released electrical energy is connected to the electromagnetic coupler via the AC / DC converter and the electrical port. The conventional drive system is located in the front compartment and front axle of the vehicle. The drive motor is connected to the main reducer 3 via the transmission, which drives the half-shaft 2 to rotate, thereby driving the front wheel 1 to rotate.

[0029] The electromagnetic coupler 6 adopts a double rotor motor, and is provided with three output input ports (or interfaces), which are a first mechanical port (or a first mechanical interface), a second mechanical port (or a second mechanical interface) and an electrical port (or an electrical interface). The first mechanical port is an outer rotor shaft 6-1, the second mechanical port is an inner rotor shaft 6-2, and the electrical port is a slip ring 6-3 arranged on the outer rotor shaft. The working principle of the double rotor motor is similar to that of a permanent magnet synchronous motor, so the double rotor motor can be regarded as a permanent magnet synchronous motor with a rotatable stator. The electromagnetic coupler is arranged between a flywheel and a rear wheel. When the vehicle is decelerating, the clutch is engaged, and the kinetic energy transmitted by the rear wheel of the vehicle is stored in the flywheel through a two-stage gear transmission pair after being increased in speed. When the vehicle is accelerating, the energy of the flywheel is released to meet the performance requirements of the vehicle driving system. The electric energy generated by the electromagnetic coupler is stored in the power battery or the energy storage battery of the vehicle. When necessary, the electromagnetic coupler can also work in a motor state as an auxiliary power source. The existing processing control device of the vehicle can be used as a controller of the energy storage device under the support of software, or an independent controller of the energy storage device can be arranged to receive real-time detection information of various sensors and brake information (for example, brake pedal signal) and acceleration information (for example, accelerator pedal signal) of the vehicle, so as to control the clutching state of the flywheel clutch. The arrangement modes of the inner rotor speed sensor 10, the outer rotor speed sensor 9 and the clutch 11 can be based on the prior art. The flywheel rotation sensor can be arranged based on the prior art to obtain the real-time speed of the flywheel.

[0030] The electromagnetic coupling transmission is a non-contact torque transmission mode. The electromagnetic coupler can be essentially regarded as an alternating current motor with rotatable stators and rotors, that is, a double rotor motor, which has three-phase windings on the outer rotor and permanent magnets arranged on the inner rotor. Two mechanical ports are connected to corresponding transmission mechanisms to connect the vehicle (rear wheel system) and the flywheel, and the electrical port is connected to the battery through an AC / DC circuit. The clutching state of the flywheel clutch can be controlled by a controller, and the circuit between the electrical port and the AC / DC circuit (or the battery) can be controlled to be turned on or off. When the circuit is turned off, the electrical port can be regarded as an open circuit.

[0031] According to the law of conservation of energy, in the case that 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 electric energy input by the controller - the loss of the inner and outer rotors. Since the controller is mainly used to process the difference of mechanical power, the capacity of the controller can be relatively small, about 15% of the capacity of a synchronous generator.

[0032] The speed signals of the inner and outer rotors collected by the speed sensors of the inner and outer rotors and the signals of the accelerator pedal and the brake pedal of the automobile are used to determine whether the electromagnetic coupler is in the power generation state or the power driving state. According to the real-time speed of the flywheel, when the automobile is decelerating, the clutch is controlled to be engaged, the kinetic energy transmitted by the rear wheels of the automobile is increased in speed through the two-stage gear transmission pair, the flywheel is driven to increase in speed, the energy is stored in the flywheel, and the electric energy generated is stored in the battery; when the vehicle needs to accelerate, the flywheel releases energy as an auxiliary power source to meet the performance requirements of the automobile driving system. In the above energy recovery and release process, the electromagnetic coupler is controlled to realize the conversion of the kinetic energy of the automobile (rear wheels) and the flywheel. The electromagnetic coupler can be appropriately set so that the conversion amount of electric energy is much smaller than the total energy in the mechanical energy conversion process.

[0033] To quantitatively describe the characteristics of the electromagnetic coupling type brake energy recovery system, the mechanical angular velocities of the inner rotor and the outer rotor are defined as ω mi 、ω mo , the differential mechanical angular velocity and the differential power are ω m 、P s , the rated angular velocity, the rated power and the 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:

[0034]

[0035] It is assumed that the electromagnetic coupler works at the rated torque and satisfies ω mi =kω N , ω mo =(k+

[0036] 1)ω N , k≥0. If the effects of the moments of inertia of the inner and outer rotors and the viscous friction coefficient are not considered, the input power P o , the output power P i , the differential power and the differential angular velocity of the coupler satisfy the following formula:

[0037]

[0038] Table 1 shows the values of the mechanical port power, torque and speed of the electromagnetic coupler when k is 0, 1.0 and 1.5.

[0039] Table 1. Mechanical port power of electromagnetic coupler under different k values

[0040]

[0041] When k = 0, the inner rotor is fixed, and the electromagnetic coupler is equivalent to a common motor; when k > 0, the inner rotor is released from the fixing, and the electromagnetic coupler is equivalent to a double-mechanical-port motor, and due to the rotation of the inner rotor shaft, the induced voltage on the winding is reduced, at this time, the torque-speed characteristic of the coupler is right-shifted, as shown in Fig. Figure 2 .

[0042] Although the electric drive system has good acceleration performance at low speed, the driving torque is insufficient due to the operation in the constant power region at high speed; on the other hand, the motor regenerative braking force is limited by the available output torque of the motor during high-speed braking of the traditional electric vehicle. Figure 2 As can be seen from the T-ω characteristic of the electrical port of the electromagnetic coupler in the middle, the electromagnetic coupling type brake energy recovery system can exert the maximum torque at different speed ranges, that is, the operating point of the system changes and moves to the high-speed region.

[0043] According to formula (2), when the electromagnetic coupling type brake energy recovery system operates at the rated torque, the power that can be transmitted by the mechanical port is much greater than the rated power, the power recovered from the wheels by the flywheel is not affected by the rated power of the motor and the power electronic equipment, and the energy is directly stored in the form of mechanical energy, and the battery only needs to recover the differential power in the form of electrochemical energy.

[0044] According to actual needs, during use, the working mode of the utility model can be controlled according to actual needs, and according to the energy change mode of the flywheel, the flywheel energy recovery (referred to as energy recovery) mode or the flywheel energy release (referred to as energy release) mode can be formed, and in addition, the flywheel or the rear wheel (relative to the system being cut from the vehicle drive system) can be cut off to form the corresponding working mode.

[0045] 1. Flywheel energy recovery mode

[0046] For example, when the automobile is decelerated (braked), the clutch 11 is combined, the rear wheel 4 of the vehicle drives the electromagnetic outer rotor shaft 6-1 to rotate through the first transmission mechanism (usually a gear transmission mechanism, or a gear pair) 5, and the inner rotor shaft 6-2 is speeded up through the second transmission mechanism (usually a gear transmission mechanism, or a gear pair) 7 and stored in the flywheel.

[0047] To quantitatively describe the size of the energy conversion amount during the deceleration of the automobile, it is assumed that the active power transmitted to the outer rotor shaft through the first transmission mechanism is P o , 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 differential power P s in the inner rotor, and satisfies the following formula:

[0048]

[0049] Where s is the slip ratio.

[0050] Mechanical power of inner rotor P emch Subtract mechanical loss P ml Output to the input shaft of the second transmission, at this time the active power on the inner rotor shaft is P i ; slip power P s Subtract copper loss and stray loss of inner rotor winding P el After which can be stored in the battery through the controller inverter (loss P bl ).

[0051] The specific working mode in the energy recovery mode can be controlled according to the actual working condition and control strategy of the vehicle. For example:

[0052] Figure 3 A working mode and the corresponding energy conversion process when the angular velocity of the outer rotor shaft is greater than the angular velocity of the inner rotor shaft are shown. The mechanical power of the inner rotor shaft P emch is stored in the flywheel through the second transmission, the slip power P s is stored in the battery after AC / DC inversion, at this time the electromagnetic coupler is equivalent to a generator;

[0053] Figure 4 A working mode and the corresponding energy conversion process when the angular velocity of the outer rotor shaft is less than the angular velocity of the inner rotor shaft are shown. 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 is equivalent to a motor;

[0054] Figure 5 A working mode and the corresponding energy conversion process when the inner rotor and the outer rotor are at the same speed are shown. At this time, the slip power is zero, and under certain working condition changes, the mechanical power on the outer rotor shaft can be directly transmitted to the flywheel through the two mechanical ports of the electromagnetic coupler.

[0055] 2. Flywheel energy release mode

[0056] For example, in the acceleration state, the clutch 11 is engaged, and the energy stored in the flywheel acts on the rear wheels through the second transmission, the clutch, the inner rotor shaft, the outer rotor shaft and the first transmission mechanism, as an auxiliary power source.

[0057] The specific working mode in the energy release mode can be controlled according to the actual working condition and control strategy of the vehicle. For example:

[0058] Figure 6 A working mode and the corresponding energy conversion process when the angular velocity of the inner rotor shaft is greater than the angular velocity of the outer rotor shaft are shown. The mechanical power of the electromagnetic coupler P emchThe rotation difference power P is applied to the rear wheel after being decelerated by the first transmission mechanism s The power is stored in the battery after being inverted by the controller, and the electromagnetic coupler is equivalent to a generator at this time.

[0059] Figure 7 A working mode and the corresponding energy conversion process when the inner rotor shaft angular velocity is less than the outer rotor shaft angular velocity are shown. The battery can provide energy to the wheel through the electromagnetic coupler, and the electromagnetic coupler is equivalent to a motor at this time; the connection with the rear wheel can be cut off through the wheel clutch arranged between the first transmission mechanism and the rear wheel (for example, the rear wheel),

[0060] Figure 8 A working mode and the corresponding energy conversion process when the inner rotor and the outer rotor rotate at the same speed are shown. The electromagnetic coupler rotation difference power is zero, and under certain working condition changes, the mechanical energy in the flywheel can be regarded as driving the rear wheel through the two mechanical ports of the electromagnetic coupler.

[0061] The energy exchange in the two modes is shown in Table 2:

[0062] Table 2. Working mode and energy exchange relationship of the electromagnetic coupler in the two modes

[0063]

[0064] In the table, “—” represents meaningless.

[0065] The various preferred and optional technical means disclosed in the utility model can be arbitrarily combined to form several different specific embodiments, except for the special description and the further limitation of one preferred or optional technical means as another technical means.

Claims

1. A rear-wheel braking energy recovery system adapted to a front-wheel drive electric vehicle, characterized in that... The device includes an electromagnetic coupler and an energy storage flywheel. The electromagnetic coupler is a dual-rotor motor with an outer rotor shaft, an inner rotor shaft, and electrical terminals for input and output. The outer rotor shaft is connected to the rear wheel drive via a first transmission mechanism, and the inner rotor shaft is connected to the energy storage flywheel drive via a second transmission mechanism. The electrical terminals are connected to a battery via a battery management system. A flywheel clutch is provided between the inner rotor shaft and the second transmission mechanism, and a rear wheel clutch is provided between the first transmission mechanism and the outer rotor shaft or between the first transmission mechanism and the rear wheel shaft.

2. The rear-wheel braking energy recovery system adapted to a front-wheel drive electric vehicle as described in claim 1, characterized in that... Both the first transmission mechanism and the second transmission mechanism are bidirectional transmission mechanisms.

3. The rear-wheel braking energy recovery system adapted to a front-wheel drive electric vehicle as described in claim 1, characterized in that... A flywheel speed sensor is provided for real-time detection of flywheel speed, and the output of the flywheel speed sensor is connected to a controller for controlling the flywheel clutch status and the rear wheel clutch device.

4. The rear-wheel braking energy recovery system adapted to a front-wheel drive electric vehicle as described in claim 1, characterized in that... An external rotor speed sensor is provided for real-time detection of the external rotor speed. The output of the external rotor speed sensor is connected to a controller for controlling the flywheel clutch status and the rear wheel clutch device.

5. The rear-wheel braking energy recovery system adapted to a front-wheel drive electric vehicle as described in claim 1, characterized in that... An inner rotor speed sensor is provided for real-time detection of the inner rotor speed, and the output of the inner rotor speed sensor is connected to a controller for controlling the flywheel clutch state and the rear wheel clutch device.

6. The rear-wheel braking energy recovery system adapted to a front-wheel drive electric vehicle as described in claim 1, characterized in that... The dual-rotor motor adopts a three-phase permanent magnet motor structure.

7. The rear-wheel braking energy recovery system adapted to a front-wheel drive electric vehicle as described in claim 1, characterized in that... The three-phase windings of the dual-rotor motor are mounted on the outer rotor. The electrical terminals are slip ring assemblies for connecting the three-phase windings. The slip ring assemblies consist of multiple slip rings corresponding to each winding and are mounted on the outer rotor shaft.

8. The rear-wheel braking energy recovery system adapted to a front-wheel drive electric vehicle as described in claim 1, characterized in that... The inner rotor is equipped with a permanent magnet.

9. The rear-wheel braking energy recovery system adapted to a front-wheel drive electric vehicle as described in claim 1, characterized in that... The flywheel clutch is either an electromagnetic clutch or a friction clutch.

10. The rear-wheel braking energy recovery system adapted to a front-wheel drive electric vehicle as described in claim 1, characterized in that... The rear wheel clutch is either an electromagnetic clutch or a friction clutch.

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