Novel motor special for electric automobile and using method thereof

Abstract

According to the operation principle of the motor, the through-flow conductor rotates under the action of force in a magnetic field, induced electromotive force E generated after rotation is equal to Ce phi n (n is the rotating speed of the rotor relative to the stator, namely the rotating speed difference between the rotor and the stator), and electromagnetic torque T generated after rotation is equal to CT phi Ia (Ia is armature loop current). A voltage balance equation (taking a shunt excitation DC motor as an example) in a motor loop after rotation is U = E + IaRa. (Ra is the internal resistance of the armature circuit). At the moment, if the rotating speed n is reduced, the induced electromotive force E is reduced, and if the input voltage U and the magnetic flux phi in the magnetic field are kept unchanged, the armature current Ia is increased, so that the electromagnetic torque T is increased, and the correctness of the theory is verified by an author through a test. According to the scheme, the motor stator is driven to rotate by inertia force during automobile running, the rotating speed difference n between the stator and the rotor is reduced, and therefore electromotive force E is reduced. As the speed difference between the rotor and the stator is very small, very large torque can be generated in the rotor, and electromagnetic loss is also reduced at the same time.

Description

1. Technical Field

[0001] The field of new energy electric vehicles. 2. Background Art

[0002] With the increasing global attention to environmental protection and the demand for sustainable development, electric vehicles have become the future direction of the automotive industry. However, although electric vehicles have made significant progress in reducing carbon emissions and improving energy efficiency, they still face challenges such as driving range and battery safety.

[0003] This solution will introduce a new invention to you. This technology mainly has three technical features: one is to maintain the maximum torque output of the electric vehicle at any moment of movement; the second is to greatly reduce the electromagnetic loss of the electric vehicle and improve the driving range of the electric vehicle; the third is to allow the electric vehicle to switch arbitrarily between front-wheel drive and rear-wheel drive modes with only one motor installed.

[0004] The application of this technology can greatly improve the driving experience and safety factor of users.

[0005] At present, the core motors in electric vehicles on the market generally use two types of motors, one is a permanent magnet DC motor, and the other is an AC synchronous motor. No matter which motor, their operating principles are the same. This solution takes the DC motor as an example to introduce.

[0006] The solution starts from the operating principle of the motor, analyzes the feasibility of the solution from the deep principle, then introduces the specific implementation method, and finally introduces the specific working condition analysis of the solution during vehicle driving.

[0007] Note: This solution is also applicable to all wheel-driven electric vehicles such as electric motorcycles and electric bicycles. This specification only takes electric vehicles as an example for illustration. 3. Summary of the Invention

[0008] 3.1. Utilize vehicle inertia to increase motor torque and reduce power consumption

[0009] This solution utilizes the inertial force during vehicle driving to drive the rotation of the motor stator, reduces the speed difference between the motor stator and rotor, reduces the electromotive force, and increases the armature current in the motor, thereby reducing electromagnetic loss and achieving the purpose of increasing torque and reducing power consumption of the electric vehicle.

[0010] According to the operating principle of an electric motor, a current-carrying conductor is subject to force in a magnetic field, causing it to rotate. This rotation generates an induced electromotive force (E) = CeΦn (where n is the rotor's speed relative to the stator, i.e., the speed difference between the rotor and stator). This rotation also generates an electromagnetic torque (T) = CTΦIa (where Ia is the armature circuit current). The voltage balance equation in the motor circuit after rotation (using a shunt-excited DC motor as an example) is U = E + IaRa (Ra is the resistance in the armature circuit). If the speed n is reduced, the induced electromotive force (E) decreases. If the input voltage (U) and the magnetic flux (Φ) in the magnetic field remain unchanged, the armature current (Ia) increases, thereby increasing the electromagnetic torque (T).

[0011] From the knowledge of mechanics, we know that when a car is running at a constant speed, the resistance and traction it encounters are a pair of equal and opposite action and reaction forces. The car maintains a state of constant motion under the action of gravity, which is a state of inertia.

[0012] Suppose a car weighs 2000kg. When it travels at a constant speed of 100km / h, its tire speed is 6000 rpm, and the traction force it is subjected to is about 9550 Nm. At this time, the force generated by the car's inertia is about 842310 Nm (this is the total force borne by the four wheels, and the actual situation will be less than this value). It can be seen that the car has very large inertial energy during normal driving.

[0013] 3.2. Verification test

[0014] To analyze the force applied to the motor during rotation, the author conducted three small experiments. The motor model used in the experiments was AEM716212-02, DC18V, N094K2, and the measuring instrument was a Fluke F17B multimeter. The specific test process is as follows:

[0015] 1) When the motor stator is fixed, the rotor will rotate after power is applied, and the voltage is 3.9V and the current is 0.74A during rotation. When the motor rotor is fixed, the stator will rotate after power is applied, and the voltage and current during rotation are no different from when the rotor is rotating (it may be that the on-site measurement meter is not accurate enough to distinguish the difference).

[0016] 2) When the stator and rotor of the motor are fixed by hand at the same time, the voltage is 3.9V and the current is 8.5A after power is turned on. At the same time, it can be clearly felt that the rotor and stator are subjected to a pair of opposite forces and reaction forces.

[0017] 3) Continue with test ②. While holding the stator and rotor of the motor by hand, when rotating the stator in the direction of the rotor, you can clearly feel a significant increase in resistance. The current reaches 9.0A and the voltage drops to 3.6V.

[0018] Note: Due to the large force of the motor, the second and third test processes are short, and are affected by the accuracy and sensitivity of the meter, so the test measurement results have certain errors.

[0019] Based on the above experiments, the following conclusions can be drawn:

[0020] 1) When the motor rotates, there is a pair of action and reaction forces in opposite directions between the rotor and the stator. This pair of forces can cause the rotor to rotate as well as the stator to rotate. The specific result is that the object with smaller mass will rotate around the object with larger mass.

[0021] 2) Changes in the relative spatial positions of the motor's field current conductors and armature current conductors affect the forces acting on the motor's stator and rotor. The test results show that when the field winding rotates toward the armature winding, the armature winding's reaction force increases. In other words, when the field winding rotates toward the armature winding, it pushes the armature winding in the same direction.

[0022] 3) According to the voltage balance equation: U=E+I a R a , I a =(UE) / R a When the stator and rotor of the motor are fixed, since the speed n = 0, the electromotive force E = 0, and at this time I a =U / R a , the current is maximum and the torque is maximum.

[0023] 4) According to the power balance equation: P1=P em +P2+P0, when the mechanical power P2 demand is fixed, if the P em , the entire input power P1 will decrease, that is, the energy consumption will be reduced. 4. Illustrations

[0025] Note: The same components in the following figures use the same identification numbers.

[0026] Figure 1 -Front view of the motor interior:

[0027] The components in the figure are labeled as follows: ① motor rotor; ② motor stator; ③ motor stator bearing; ④ motor rotor bearing; ⑤ base.

[0028] Figure 2 -Side view of the motor:

[0029] The components in the figure are marked as follows: ⑥ Motor rotor drive shaft; ⑦ Motor stator drive shaft; ⑧ Carbon brush; ⑨ Collector ring; ⑩

[0030] Motor stator protection housing.

[0031] Regarding the attached Figure 1 and the attached Figure 2 Brief description:

[0032] 1) There is a protective housing (⑩ in the figure) outside the motor stator. The stator is fixed on the protective housing (as shown in the figure). The protective housing is not directly fixed on the motor housing. Instead, a bearing (③ in the figure) is sleeved outside it. The outer ring of the bearing is then fixed to the motor housing or the bearing is directly fixed to the vehicle body, keeping the motor stator able to rotate at high speed. The outer ring of the rotor bearing (④ in the figure) is fixed in the protective housing. Both the rotor and the stator can rotate and can only rotate in one direction. The positive rotation direction must be the direction to drive the car forward. The bearing should be able to withstand high rotational speeds and high load requirements. Anti-reverse measures should be taken for the stator and rotor, such as installing a one-way bearing, etc.

[0033] 2) One end of the protective housing of the motor stator is connected to the drive shaft (⑦ in the figure), and the rotor has a drive shaft (⑥ in the figure) at the other end. That is, each of the motor stator and rotor has one end that can output power, but only one can be the power source at the same time, and the other is the non-power source.

[0034] 3) Since the motor stator needs to rotate, a set of power supply devices for the stator during high-speed rotation, namely carbon brushes (⑧ in the figure)

[0035] and slip rings (⑨ in the figure), are required to keep power supply to the stator. The rotor can use high-performance permanent magnets (if the rotor is also designed in the electromagnetic form, a separate power supply circuit for the rotor needs to be designed).

[0036] Figure 3 - Drive system layout diagram:

[0037] The identification of each component in the figure is as follows: ⑾ differential; ⑿ transmission; ⒀ torque conduction controller; ⒁ motor.

[0038] Regarding the attached Figure 3 Brief description:

[0039] 1) Connect the drive shaft of the front and rear axle differentials (11 in the figure) of the car to the transmission (12 in the figure), and then the transmission is connected to the torque conduction controller (13 in the figure). Note that the gear configurations and shifting logics of the two transmissions must be exactly the same and there must be a reverse gear. The motor is installed longitudinally, and the installation direction is not restricted. In this figure, the output shaft of the front axle torque conduction controller is connected to the drive shaft of the motor stator (⑦ in the figure), and the output shaft of the rear axle torque conduction controller is connected to the drive shaft of the motor rotor (⑥ in the figure);

[0040] Or the motor can also be installed in the reverse direction with the connection method unchanged.

[0041] 2) The torque conduction controller transmits and switches on / off the torque, such as a hydraulic coupling or a clutch, etc. The connection principle is that the torque conduction controller at the driving end is rigidly connected to the transmission device, and the torque conduction controller at the non-driving end is flexibly connected to the transmission device, and the torque conduction controller should be able to switch between flexible conduction and rigid conduction. However, if the torque conduction controller cannot switch between flexible torque conduction and rigid torque conduction, that is, the torque conduction controller has only one fixed working mode, then the driving axle of the vehicle can only be fixed to front axle drive or rear axle drive and cannot be switched.

[0042] 3) The black arrow in the figure indicates the vehicle driving direction. 5. Specific implementation method

[0043] Currently, almost all the usage methods of electric motors are to fix the stator, rotate the rotor, and make the rotor rotate to output power by the mutual force between the stator and the rotor. If the stator can also be rotated, then the rotational speed difference between the stator and the rotor can be reduced, thereby reducing the electromotive force E.

[0044] This solution exactly uses the inertial force during vehicle driving to drive the rotation of the electric motor stator. For electric vehicles, the specific implementation method is as follows:

[0045] 5.1. Design a new electric motor, which should have the following characteristics (such as Figure 1 and Figure 2 ):

[0046] 1) When the electric motor is running, the stator and the rotor can rotate independently and can only rotate in one direction. The electric motor or the carrier of the electric motor should have a design to prevent the stator and the rotor from reversing, and the rotation of the stator and the rotor is controlled by other components.

[0047] 2) The motor must have two power output ends, one is the power output of the rotor, and the other is the power output of the stator. When the motor is running, one of the output ends is the power source to drive the wheels to rotate; the other output end is the non-power source to receive the power feedback of another set of wheels.

[0048] 3) The electric motor can change the power output source by changing the positive and negative poles of the input power supply (if it is an AC motor, it is to change the power supply phase sequence). For example, if the rotor is the power source before changing the polarity (or direction), then the stator is the power source after the change. After changing the power source, the rotation directions of the stator and the rotor remain unchanged, that is, it still drives the vehicle forward instead of backward.

[0049] 4) Since the electric motor stator needs to rotate, a set of brush power supply devices is required for the stator coil. This set of brush devices should ensure reliable power supply while withstanding the high-speed rotation centrifugal force.

[0050] 5.2. Modify the vehicle chassis. The specific modification plan is (such asFigure 3 ):

[0051] 1) Arrange the motor described in 5.1 longitudinally in the vehicle. There is no restriction on the orientation of the driving ends of the stator and rotor. In this design, the driving end of the stator faces the front axle of the vehicle, and the driving end of the rotor faces the rear axle of the vehicle.

[0052] 2) Connect the driving ends of the motor rotor and stator to the front and rear axles of the vehicle respectively through a set of torque conduction controllers (such as clutches or fluid coupling torque converters) and a gearbox. Since this set of design allows the vehicle to freely choose between front-wheel drive and rear-wheel drive, it is required that the torque conduction controller should have the functions of rigid conduction and flexible conduction of torque, that is, it can select between rigid conduction and flexible conduction of torque when needed. In addition, since the stator and rotor of the motor cannot rotate in reverse and the vehicle cannot reverse by reversing the motor, it is required that the gearbox must have a reverse gear, and there is no restriction on the forward gears.

[0053] 3) In this design, when the vehicle is running, if the driving source is the motor rotor, the vehicle is a rear-wheel drive vehicle. The torque conduction between the rotor and the transmission must be rigid, and the torque conduction between the stator and the transmission must be flexible; if the driving source is changed to the stator, the vehicle becomes a front-wheel drive vehicle. At this time, the torque conduction between the rotor and the transmission must be flexible, and the torque conduction between the stator and the transmission must be rigid. The above measures are to ensure that the torque conduction between the non-driving end and the wheels during vehicle operation is unidirectional, avoiding the influence of the non-driving end on the rotation of the wheels.

[0054] 6. Analysis of vehicle operating conditions

[0055] When the vehicle is driving at high speed, under the action of inertial force, the transmission system connecting the non-power source (such as the stator) of the motor drives the stator of the motor to rotate under the drive of the wheels; while the motor rotor drives another set of wheels to drive normally. Since the speed difference between the rotor and the stator is very small, a large torque will be generated in the rotor, and the electromagnetic loss is very small, which can greatly save the power consumption. If the armature current is operated in a pulsed power-on mode (without affecting the feelings of the passengers and drivers), the power consumption can be further reduced.

[0056] The following content stipulates that the rotation direction of the tires during forward driving of the vehicle is the reference positive direction, that is, the clockwise direction is the positive direction, and the shifting logic of the front and rear axle transmission devices is exactly the same. Due to the symmetrical design of the front and rear axles, the vehicle switches between the rear-wheel drive and front-wheel drive modes.

[0057] 6.1. Starting

[0058] The front axle torque conduction controller does not transmit torque, while the rear axle torque conduction controller transmits torque. Before starting, both the stator and rotor of the motor are stationary. During startup, similar to a normal motor, forces and reaction forces are generated between the stator and rotor. The rotor rotates clockwise, and the stator remains fixed and cannot reverse, so the vehicle starts to move forward.

[0059] 6.2. Low-speed and uniform driving

[0060] At this time, the vehicle speed is low, and the inertial force of the vehicle is less than the traction force. Although the front axle torque conduction controller transmits torque, the torque is not sufficient to overcome the reaction force of the rotor. Therefore, the stator is stationary or rotates very slowly; the rear axle torque conduction controller transmits torque, and the force and rotation conditions between the stator and rotor are the same as when the vehicle starts, and the vehicle maintains a forward driving state. Note that at this time, if the stator starts to rotate, even if the rotation speed is very slow, it can still reduce the electromotive force E, thereby enhancing the torque during low-speed driving.

[0061] 6.3. Acceleration

[0062] 1) If the inertial force of the vehicle is less than the traction force at this time, the driving state is the same as in 6.1 (startup).

[0063] 2) If the inertial force of the vehicle is greater than the traction force at this time, both the front and rear axle torque conduction controllers transmit torque, and the stator of the motor will rotate clockwise together with the wheels. The speed difference between the stator and rotor decreases, the electromotive force E decreases, the acceleration torque increases, and the faster the vehicle speed, the greater the acceleration torque.

[0064] 6.4. High-speed and uniform driving

[0065] At this time, the inertial force of the vehicle is greater than the traction force, and both the front and rear axle torque conduction controllers transmit torque. The stator of the motor rotates clockwise together with the wheels, and the speeds of the stator and rotor coils are the same (or nearly the same), and the electromotive force E≈0. At this time, if the input voltage U is reduced, the total input power P = UI a will decrease, reducing the power consumption of electric energy, thereby extending the driving range of the electric vehicle.

[0066] 6.5. Braking and deceleration

[0067] There are the following two solutions for braking and deceleration:

[0068] 1) Both the front and rear axle torque conduction controllers transmit torque to reduce the input armature current I a , and the wheels continue to rotate forward under the action of inertia. Affected by the reaction force of the rotor, the stator tends to stop rotating. Therefore, the front wheels will decelerate; at this time, continuously reduce the input voltage U and the armature current I a , the torque of the rotor rotation will become smaller, and the speed difference between the stator and rotor tends to decrease, that is, the rotational speed of the rear wheels will also decrease accordingly, and the vehicle will continue to decelerate.

[0069] 2) The front axle torque conduction controller does not conduct torque, while the rear axle torque conduction controller conducts torque. Affected by the reaction force of the rotor, the stator tends to stop rotating (until it stops), reducing the input armature current I. a , if the input voltage U is simultaneously reduced so that U < E, the motor enters the power generation state, and at this time the motor operates in the kinetic energy feedback braking state.

[0070] The above process, when combined with the vehicle braking system, can effectively shorten the vehicle braking distance and improve driving safety.

[0071] 6.6. Uphill

[0072] Same as 6.3 Acceleration.

[0073] 6.7. Downhill

[0074] According to the setting of the vehicle computer, the motor can operate in the state of 6.4 (high-speed uniform driving) or 6.5 (braking and decelerating).

[0075] 6.8. Stop

[0076] Both the front and rear axle torque conduction controllers conduct torque, and both the stator and rotor of the motor are stationary.

[0077] 6.9. Reverse

[0078] The gear positions of both the front and rear axle transmissions are set to reverse. The front axle torque conduction controller does not conduct torque, while the rear axle torque conduction controller conducts torque. The rotor of the motor rotates clockwise, and the force conditions of the stator and rotor are the same as in 6.1 (start-up), and the vehicle moves backward.

[0079] 6.10. When the driving wheel tires slip

[0080] When the rear wheels (driving wheels) slip, reverse the positive and negative poles of the DC power supply (change the phase sequence for AC power supply). At this time, the rotation direction of the stator is clockwise, and the rotation direction of the rotor is counterclockwise, but the rotor cannot reverse. The vehicle is driven by the front wheels and becomes a front-wheel drive mode.

[0081] At this time, the stator is the power source, rigidly connected to the front axle transmission, and the rotor is flexibly connected to the rear axle transmission; the rotation direction is still clockwise.

[0082] The specific analysis of the operating conditions is the same as in 6.1 - 6.9.

Claims

1. A new type of motor dedicated to electric vehicles, characterized in that There is a protective housing ⑩ outside the motor stator. The stator is fixed inside the protective housing. A bearing ③ is sleeved outside the protective housing. The outer ring of the bearing is fixed to the motor housing or the bearing is directly fixed to the vehicle body. The outer ring of the rotor bearing ④ is fixed in the motor protective housing. Both the rotor and the stator can rotate independently. And when the motor is running, the stator and the rotor can only rotate in the same direction. There should be measures to prevent the stator and the rotor from reversing (such as installing a one-way bearing). A set of power supply device carbon brushes ⑧ and slip rings ⑨ are also installed on the motor stator protective housing to keep power supply to the rotating stator. One end of the motor stator protective housing is connected to a drive shaft ⑦, and the rotor also has a drive shaft ⑥ at the other end. That is, one end of the motor stator and the rotor can output power respectively, but only one can be the power source and the other is the non-power source at the same time. The motor is applicable to all types of DC motors and AC motors.

2. The novel motor dedicated for electric vehicles according to claim 1, characterized in that The connection method between the motor and the vehicle drive axle is as follows: The drive shaft of the motor power source is connected to the differential (11) of the vehicle drive axle through a set of torque transmission controllers (13) and a transmission device (12). The torque transmission between the drive shaft and the torque transmission controller is rigid; while the drive shaft of the non-power source of the motor is connected to the differential (11) of the non-drive axle of the vehicle through another set of torque transmission controllers (13) and a transmission device (12). The torque transmission between the drive shaft and the torque transmission controller is flexible; the above two sets of torque transmission controllers should both be able to switch between flexible transmission and rigid transmission.

3. A novel motor dedicated for electric vehicles according to claim 2, characterized in that If the torque transmission controller cannot switch between flexible torque transmission and rigid torque transmission, that is, the torque transmission controller has only one fixed working mode, then the vehicle drive axle can only be fixed to front axle drive or rear axle drive; the gear settings and shifting logics of the two sets of transmission devices must be exactly the same, and there should be at least one reverse gear.

4. The usage method of a novel motor dedicated to an electric vehicle according to claim 1 or 2, characterized in that Utilize the inertial force during vehicle driving to drive the rotation of a non-power source drive shaft of the motor through a set of axle drive systems, while the drive shaft of the power source of the motor drives the vehicle to run normally through another set of axle drive systems. When the vehicle is running normally, the rotational speed difference between the motor stator and the rotor is very small, and the power output source of the motor and the vehicle drive axle can be changed by changing the positive and negative poles or phase sequence of the motor power supply, but the vehicle driving direction remains unchanged.

5. The usage method of a novel motor dedicated for electric vehicles according to claim 1 or 2, characterized in that The motor can operate by pulsed power supply during operation.

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