TWI778558B - Driving system and driving control method for electric vehicles - Google Patents

Abstract

A driving system and a driving control method for electric vehicles are disclosed. The disclosure is to retrieve the steering information of the steering device and the reference velocity of the electric vehicle, determine the left driving control command and the right driving control command with velocity difference based on the steering information and the reference velocity, and control the velocity difference between the left driving module and the right driving module. The disclosure can implement stable steering and improve safety.

Description

Drive system of electric vehicle and drive control method thereof

The present invention is related to an electric vehicle, especially a drive system of the electric vehicle and a drive control method thereof.

In the existing electric vehicles (such as electric tricycles), a single motor is used to provide power to all the driving wheels (such as two rear wheels), and this setting method makes all the driving wheels have the same speed, and can not flexibly steer , and there are safety risks such as overturning.

At present, another electric vehicle with wheel speed difference has been proposed. The aforementioned electric vehicle is provided with a set of mechanical differentials, and during the steering process, the mechanical structure is used to distribute more power to the outer drive wheels during steering, thereby increasing the steering speed. However, adding a mechanical differential would increase the size of the electric vehicle (eg, increase the wheelbase), reduce steering flexibility (increase the turning radius), and increase cost. In addition, the power distribution of the mechanical differential is fixed, which makes it impossible for the mechanical differential to dynamically adjust the power distribution according to the current speed and steering range.

Therefore, the existing electric vehicles have the above problems, and more effective solutions are urgently needed.

The main purpose of the present invention is to provide a drive system of an electric vehicle and a drive control method thereof, which can realize speed difference control between driving wheels through multiple drive modules and electronic differential control.

The present invention provides a drive system of an electric vehicle, which includes a left drive module, a right drive module, a steering device and a control module. The left driving module is used for providing power to a left driving wheel to control the rotation of the left driving wheel; the right driving module is used for providing power to a right driving wheel to control the rotation of the right driving wheel; the steering device is used for The direction of a steering wheel is changed by accepting a steering operation, and a steering information is obtained; the control module is electrically connected to the left driving module, the right driving module and the steering device, and is set based on the steering information and the steering device. A reference speed of the electric vehicle calculates a left drive control command and a right drive control command, controls the speed of the left drive module through the left drive control command, and controls the right drive module through the right drive control command. speed. Wherein, during the steering process, the control module generates the left drive control command and the right drive control command with a speed difference, so as to make the electric load drive through the speed difference between the left drive wheel and the right drive wheel Steady steering.

The present invention also provides a drive control method, which is applied to a drive system of an electric vehicle. The drive system includes a left drive module for driving a left drive wheel, and a right drive module for driving a right drive wheel. Set, a steering device for changing the orientation of a steering wheel, and a control module, the method includes the following steps: a) obtaining a steering information corresponding to the orientation of the steering wheel through the steering device; b) in the control The module obtains a reference speed of the electric vehicle; c) calculates a left drive control command and a right drive control command based on the steering information and the reference speed of the electric vehicle; and, d) passes the left drive control command Control the speed of the left drive module, and control the speed of the right drive module through the right drive control command, wherein the left drive control command and the right drive control command generated during the steering process have a speed difference, so as to pass The speed difference between the left driving wheel and the right driving wheel makes the electric vehicle steer stably.

The present invention can realize stable steering and improve safety.

1: Electric vehicle

10: Differential controller

11: Left Motor Controller

12: Right motor controller

13: Left motor

14: Right motor

15: Left drive wheel

16: Right drive wheel

2: Electric vehicle

20: Control Module

21: Steering device

22: Left drive module

23: Right drive module

24: steering wheel

25, 26: drive wheel

30: Steering Structure

31: Speed control structure

32: Speed acquisition module

33: Steering Sensing Module

40: Right drive circuit

41: Right frequency conversion module

42: Right motor

43: Right Motor Sensor

44: Right transmission structure

50: Left drive circuit

51: Left inverter module

52: Left motor

53: Left Motor Sensor

54: Left transmission structure

60: Corner calculation module

61: Speed calculation module

62: Drive control module

620: Left drive control module

621: Right drive control module

63: Differential control module

630: Left speed control module

631: Right speed control module

64: Magnetic Field Guided Control Module

640: Left Magnetic Field Guided Control Module

641: Right Magnetic Field Guided Control Module

701: Steering information input

702: Reference speed input

704, 705: Corner calculation

706, 707: Combination

708, 709: factor addition and multiplication

710, 711: Speed feedback

712, 713: Speed control

714, 715: FOC

716, 717: Separation and Drive Circuits

718, 719: Frequency conversion processing

720, 721: Motor

722, 723: Hall sensor

724, 725: Speed calculation

80: steering wheel

81: Left drive wheel

82: Right drive wheel

83: Center of Gravity

84: Bend Center

θ: corner

C ₁ : Left differential command

C ₂ : Right differential command

C ₃ : Left drive command

C ₄ : Right drive command

delta: steering information

δ ^* : steering coordinates

C _l : Left drive control command

C _r : Right drive control command

H _l : Sensing data of the left motor

H _r : Sensing data of the right motor

L: length

W: Wheelbase

R: distance

PWM: pulse signal

ω _v : speed change signal

ω _c : current speed

ω ^* : reference speed

ω _l : Left feedback speed

:左參考速度

: Left reference speed

ω _r : right feedback speed

:右參考速度

: Right reference speed

K _scale : factor

T _1L , T _2L , T _3L , T _4L , T _5L , T _6L : Left inverter/power crystal switch

T _1R , T _2R , T _3RL , T _4R , T _5R , T _6R : Right inverter/power crystal switch

:左參考速度控制訊號

: Left reference speed control signal

:右參考速度控制訊號

: Right reference speed control signal

S10-S13: The first control step

S20-S28: Second control step

S30-S31: Steering steps

S40-S43: Reference speed setting steps

S50-S53: Drive Steps

FIG. 1 is a structural diagram of an electric vehicle with a dual motor controller.

FIG. 2 is a structural diagram of a drive system of an electric vehicle according to an embodiment of the present invention.

FIG. 3 is a structural diagram of a steering device according to an embodiment of the present invention.

FIG. 4 is a structural diagram of a right driving module according to an embodiment of the present invention.

FIG. 5 is a structural diagram of a left drive module according to an embodiment of the present invention.

FIG. 6 is a structural diagram of a control module according to an embodiment of the present invention.

FIG. 7 is a circuit structure diagram of a driving system according to an embodiment of the present invention.

FIG. 8 is a flowchart of a driving control method according to the first embodiment of the present invention.

FIG. 9A is a first flowchart of a driving control method according to a second embodiment of the present invention.

FIG. 9B is a second flowchart of a driving control method according to an embodiment of the present invention.

FIG. 10 is a schematic diagram of steering according to an embodiment of the present invention.

Hereinafter, a preferred embodiment of the present invention will be described in detail in conjunction with the drawings.

Please refer to FIG. 1 , which is a structural diagram of a conventional electric vehicle with dual motor controllers. The left motor controller 11 of the electric vehicle 1 (such as an electric tricycle) can control the left motor 13 to provide power to the left driving wheel 15 independently, and the right motor controller 12 can control the right motor 14 to provide power to the right driving wheel 16 independently . Therefore, compared with the electric vehicle driven by a single motor, the electric vehicle 1 driven by multiple motors can solve the problem related to the transmission between the multiple driving wheels, and the transmission structure is omitted to reduce the volume.

In addition, in order to create a speed difference of the drive wheels 15, 16 when turning. The electric vehicle 1 is provided with a differential controller 10 (eg, an electronic differential). The differential controller 10 can calculate the speed difference between the two driving wheels 15 and 16 according to the rotation angle θ, and send a left differential command _C1 and a right differential command _C2 (such as different left wheel speed and right wheel speed) indicating the speed difference. ) to the left motor controller 11 and the right motor controller 12. Next, the left motor controller 11 sends a left driving command C3 to the left motor ₁₃ according to the left differential command _C1 to control the left motor 13 to rotate the left driving wheel 15 at the designated left wheel speed. And, the right motor controller ₁₂ sends a right drive command _C4 to the right motor 14 according to the right differential command C2 to control the right motor 14 to rotate the right drive wheel 16 at the designated right wheel speed. Thereby, the dynamic control of multi-motor speed difference is realized.

However, the aforementioned arrangement of the differential controller 10 will not only increase the cost, but also increase the volume of the electric vehicle 1 (eg, increase the wheelbase), and reduce the steering flexibility (increase the turning radius).

In addition, the aforementioned arrangement of the plurality of motor controllers 11 and 12 also increases the cost and volume.

In this regard, the present invention proposes a drive system for an electric vehicle and a drive control method thereof, which is used for an electric vehicle with multiple drive modules, and distributes and controls the speed of each drive module through a single control module, so as to solve the problem of "Dynamic speed difference control, volume reduction and cost reduction of electric vehicles with multiple drive modules".

In the present invention, the "steering wheel" and the "driving wheel" may be a single tire, or a plurality of tires are arranged on the same transmission shaft, which is not limited.

Although the following description of the present invention takes a rear-drive electric tricycle as an example, it does not limit the power setting position and the number of wheels of the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains can refer to the disclosure content of the present invention according to their needs, and apply the technical changes of the present invention to different power setting positions (such as front-wheel drive) and number of wheels (such as four-wheel electric vehicles), These changes all belong to the protection scope of the present invention.

Please refer to FIG. 2 , which is a structural diagram of a driving system of an electric vehicle according to an embodiment of the present invention. The electric vehicle 2 of the present invention includes a steering wheel 24 , a plurality of driving wheels 25 (taking the left driving wheel 25 and the right driving wheel 26 as an example) and a driving system.

The driving system may include a steering device 21 , a left driving module 22 , a right driving module 23 and a control module 20 electrically connected to the above-mentioned devices.

The steering device 21 is used to accept the user's steering operation to change the direction of the steering wheel 24 , and drive the vehicle body of the electric vehicle 2 to deviate in the direction (such as a left curve, a right curve or a straight line). The steering device 21 can be used to obtain steering information corresponding to the steering operation.

The left driving module 22 can provide power to the left driving wheel 25 to control the rotation of the left driving wheel 25 . The right driving module 23 can provide power to the right driving wheel 26 to control the rotation of the right driving wheel 26 . Thereby, by controlling the rotation of the left driving wheel 25 and the right driving wheel 26 , the advancing and retreating direction and speed of the electric vehicle 2 can be driven.

The control module 20 (eg, a control box including a processor (or a microcontroller, a single-chip system), a peripheral control circuit, and a connection interface) is used to control the electric vehicle 2 (eg, startup, shutdown, acceleration and deceleration, etc.).

In one embodiment, the control module 20 further serves as a controller of the left driving module 22 and the right driving module 23 . Specifically, the control module 20 can generate drive control commands (such as left drive control commands and right drive control commands), and control the rotational speed and torque of the left drive module 22 and the right drive module 23 through the drive control commands, Further, the speed of each driving wheel of the electric vehicle 2 is controlled.

Furthermore, the control module 20 can also realize asymmetric power distribution. Specifically, the control module 20 can make a speed difference between the left drive control command and the right drive control command according to different road conditions (such as slipping, being stuck with a single wheel in the air, turning, etc.), so that each drive wheel has a different speed difference. speed and power to achieve stable driving (such as different power distribution between the slipped and unslipped wheels to stabilize the car body, provide more power for the unslung wheels to get out of trouble, stabilize the steering through the inner and outer speed difference, etc.).

In one embodiment, the electric vehicle 2 is an electric tricycle with a rear-drive design. The front wheel is the steering wheel 24 , and the left driving wheel 25 and the right driving wheel 26 are symmetrically arranged rear wheels.

Please refer to FIG. 3 , which is a structural diagram of a steering device according to an embodiment of the present invention. The steering device 21 of this embodiment may include a steering structure 30 , a speed control structure 31 , a speed obtaining module 32 and a steering sensing module 33 .

The steering structure 30 (such as a faucet or a steering wheel) is connected to the steering wheel 24 , which can accept the user's steering operation and change the direction of the steering wheel 24 through a mechanical structure.

The speed control structure 31 can accept the user's speed change operation (eg, acceleration operation, deceleration operation or reverse operation) to trigger the corresponding speed change signal ω _v (eg acceleration signal, deceleration signal or reverse signal).

The speed obtaining module 32 can obtain and provide the current speed ω _c of the electric vehicle 2 , such as speeding the rotation speed of the steering wheel 24 or the driving wheels 25 - 26 (through the stopwatch gear, stopwatch line and stopwatch module). Sensing or measuring the rotational speed of the left driving module 22 and the right driving module 23 .

The steering sensing module 33 can be disposed on the steering structure 30 (or the steering wheel 24 ) to sense and provide the steering information δ of the steering structure 30 (or the steering wheel 24 ).

In one embodiment, the steering information δ may include steering coordinates. In this embodiment, the steering structure 30 is set in a coordinate system, and is passed through sensors (such as optical or mechanical positioning encoders, accelerometers, gyroscopes, electronic sensors, etc.). compass, etc.) to measure the current coordinates of the steering structure 30 (or the steering wheel 24) as the steering coordinates.

Please refer to FIG. 4 and FIG. 5 together. FIG. 4 is a structural diagram of a right driving module according to an embodiment of the present invention, and FIG. 5 is a structural diagram of a left driving module according to an embodiment of the present invention.

The right drive module 23 includes a right drive circuit 40 , a right frequency conversion module 41 , a right motor 42 and a right motor sensor 43 . The left drive module 22 includes a left drive circuit 50 , a left inverter module 51 , a left motor 52 and a left motor sensor 53

The right motor 42 and the left motor 52 are used to generate power. Specifically, the right motor 42 transmits power to the right driving wheel 26 through the right transmission structure 44 (eg, a gear set, a transmission belt or a transmission chain), and the left motor 52 transmits power to the left driving wheel 25 through the left transmission structure 54 .

In one embodiment, the right motor 42 and the left motor 52 are permanent magnet synchronous motors, but not limited thereto.

The right driving circuit 40 and the left driving circuit 50 are used for converting the analog circuit signal into a pulse signal. Specifically, the right driving circuit 40 can receive the right driving control command _Cr and output a corresponding right PWM ( _Pulse -width modulation) signal according to the right reference rotation speed of the right driving control command Cr. _The left driving circuit 50 can receive the left driving control command C1, and output the corresponding left PWM signal according to the left reference rotation speed of the left driving control command C1 _.

The right frequency conversion module 41 and the left frequency conversion module 51 are respectively used to adjust the input voltage and input current of the right motor 42 and the left motor 52 according to the received pulse signal, so as to adjust the torque of the right motor 42 and the left motor 52 respectively with rotational speed.

The right motor sensor 43 and the left motor sensor 53 (such as a Hall sensor) are respectively disposed on the right motor 42 and the left motor 52 to sense the current rotation of the right motor 42 and the left motor 52 respectively. data (such as position and speed).

Please refer to FIG. 6 , which is a structural diagram of a control module according to an embodiment of the present invention. The control module 20 of the present invention may include all or part of the following modules 60-64, 620-621, 630-631, 640-641, and the aforementioned modules are respectively used to realize different functions.

1. Steering angle calculation module 60 : configured to analyze the steering information of the steering device 21 to convert the steering coordinates of the steering structure 30 into corresponding steering angles.

2. Speed calculation module 61: is set to calculate and distribute the reference speed (left reference speed and right reference speed) of each driving wheel (left driving wheel 25 and right driving wheel 26), and generate corresponding left driving control commands and Right drive control command.

3. The drive control module 62 : is set to precisely control the rotational speed and torque of the corresponding motor according to the drive control command of each drive wheel.

In one embodiment, the drive control module 62 includes a left drive control module 620 configured to control the left motor 52 and a right drive control module 621 configured to control the right motor 42 .

4. Differential control module 63: set to monitor and correct the speed of each driving wheel, so that the sensed current actual speed (feedback speed) of each driving wheel conforms to the reference specified by the latest driving control command speed.

In one embodiment, the differential control module 63 includes a left speed control module 630 configured to correct the left current speed (left feedback speed) of the left motor 52 and a left speed control module 630 configured to correct the right current speed of the right motor 42 . Right speed control module 631 for speed (right feedback speed).

5. The magnetic field oriented control module 64: obtain the sensing data of the magnetic field change of each motor (synchronized magnetic field rotation angle) through the hall sensor, and use the Field Oriented Control (FOC) technology to Vector control is performed on each motor. Through vector control, the field-oriented control module 64 can adjust torque and rotor speed in real time, and can provide more precise control of motor performance than traditional voltage/frequency (V/F) control methods.

In one embodiment, the field-guided control module 64 includes a left field-guided control module 640 configured to precisely control the torque and rotational speed of the left motor 52 and a left magnetic field guided control module 640 configured to precisely control the torque and rotational speed of the right motor 42 . The right magnetic field is directed to the control module 641 .

The aforementioned modules are connected to each other (can be electrical connection and information connection), and can be hardware modules (such as electronic circuit modules, integrated circuit modules, SoC, etc.), software modules (such as firmware , operating system components or applications) or a mix of software and hardware modules, without limitation.

It is worth mentioning that when the aforementioned modules are software modules (eg, application programs), the control module 20 may further include a storage device. The storage device may include a non-transitory computer-readable recording medium, the non-transitory computer-readable recording medium stores a computer program, and the computer program records a computer-readable recording medium. For the executed program code, after the processor (or controller) of the control module 20 executes the aforementioned program code, the functions of the aforementioned modules can be realized.

FIG. 8 is a flowchart of a driving control method according to the first embodiment of the present invention. The driving control methods of the embodiments of the present invention can be applied to any combination of driving systems shown in FIGS. 2 to 7 . The drive control method of this embodiment includes the following steps.

Step S10 : the control module 20 obtains the steering information corresponding to the current direction of the steering wheel 24 from the steering device 21 via the rotation angle calculation module 60 . The aforementioned steering information can be coordinate information, angle information or a combination thereof, which is not limited.

Step S11 : the control module 20 obtains the reference speed of the electric vehicle 2 through the speed calculation module 61 .

In one embodiment, the control module 20 can obtain the current speed ω _c of the electric vehicle 2 from the speed obtaining module 32 , obtain the speed conversion signal ω _v from the speed control structure 31 , and adjust the current speed according to the speed conversion signal ω _v ω _c (such as acceleration, deceleration or reversal, etc.) is used as the reference speed of the electric vehicle 2, that is, the speed expected to be reached after the user inputs the speed conversion operation.

Step S12: The control module 20 calculates the left drive control command for controlling the left drive module 22 and the left drive control command for controlling the right drive module respectively according to the obtained steering information and the reference speed of the electric vehicle 2 through the speed calculation module 61 23 of the right drive control command. The aforementioned driving control command can be an analog signal or a digital signal, and is used to indicate the target speed of the corresponding driving module or the range of increase or decrease of the target speed.

Step S13 : the control module 20 controls each driving module to adjust the speed (eg, rotational speed or torque) through the driving control module 62 according to the generated driving control command.

In one embodiment, the control module 20 can control the speed of the left motor 52 of the left drive module 22 by executing the left drive control command through the left drive control module 620 , and execute the right drive control command through the right drive control module 621 . to control the speed of the right motor 42 of the right drive module 23 .

In one embodiment, in order to greatly improve the steering stability, prevent any driving wheel from hanging in the air and cause overturning, and at the same time take into account the steering speed, the present invention will determine the steering range (ie, the steering range) during the steering process (such as a right turn or a left turn). angle) to dynamically distribute the speed of the inner drive wheel and the outer drive wheel, so that there is a speed difference between the two. If the speed of the outer drive wheel is greater than the speed of the inner drive wheel, in order to adapt to the steering route, the outer route is longer than the inner route, so that all the drive wheels can stably touch the ground.

Furthermore, the present invention generates a left drive control command and a right drive control command with a speed difference during the turning process, so as to create a speed difference between the left driving wheel 25 and the right driving wheel 26 to make the electric vehicle 2 turn stably. .

In one embodiment, when the steering information indicates a right turn, the left wheel reference speed of the left drive control command is greater than the right wheel reference speed of the right drive control command, so that the left wheel driving the outer route (longer) but the speed is faster. The drive wheel 25 may maintain the same angle of turn as the right drive wheel 26, which travels the inside course (shorter) but slower.

When the steering information indicates a left turn, the reference speed of the left wheel is lower than the reference speed of the right wheel, so that the right driving wheel 26 driving the outer route but with a higher speed can maintain the same speed as the left driving wheel 25 driving the inner route but with a slower speed. the bending angle.

When the steering information is straight, the speed difference between the reference speed of the left wheel and the reference speed of the right wheel is unnecessary, so the speed difference between the reference speed of the left wheel and the reference speed of the right wheel can be controlled to be less than 5%. load imbalance), or set to 0%, without limitation.

Please refer to FIG. 10 , which is a schematic diagram of steering according to an embodiment of the present invention. FIG. 10 is used to illustrate the calculation method of the reference speed in the present invention when turning right (the same can also be applied to turning left), but this does not limit the calculation method of the reference speed covered by the present invention.

In this example, the steering wheel 80 makes a right turn based on the steering information δ, the center of gravity is the point 83 , the center of the bend is the point 84 , and the distance from the center of the bend is R. In this example, the left reference speed and the right reference speed are calculated through the following (Equation 1) and (Equation 2).

為左驅動輪的左參考速度；

為右驅動輪的右參考速度；W為左驅動輪81與右驅動輪82之間的軸距；L為載具長度(如轉向輪80與驅動輪連線之間的垂直距離)；δ為轉向資訊中的轉向角度；ω _c 為當前速度，亦可替換為前述電動載具2的參考速度(當前速度加乘速度變換訊號)；左驅動 輪81與右驅動輪82之間的速差為

。 in,

is the left reference speed of the left drive wheel;

is the right reference speed of the right driving wheel; W is the wheelbase between the left driving wheel 81 and the right driving wheel 82; L is the length of the vehicle (such as the vertical distance between the steering wheel 80 and the driving wheel); δ is The steering angle in the steering information; ω _c is the current speed, which can also be replaced with the reference speed of the aforementioned electric vehicle 2 (the current speed multiplied by the speed conversion signal); the speed difference between the left driving wheel 81 and the right driving wheel 82 is

.

Furthermore, in the above example, the steering angle of the steering wheel 80 is set as 0. When the steering information δ (such as the steering angle of 30 degrees) is greater than the threshold value (such as 0 degrees or 5 degrees), it can be determined that In order to turn right, when the steering angle δ is less than the critical value, it can be determined as a left turn, and in other cases, it can be determined as straight, but not limited to this, the direction corresponding to the positive and negative angles of the angle can be arbitrarily set according to requirements.

Please refer to FIGS. 9A and 9B together. FIG. 9A is a first flowchart of a driving control method according to a second embodiment of the present invention, and FIG. 9B is a second flowchart of a driving control method according to an embodiment of the present invention. The drive control method of this embodiment includes the following steps.

Step S20 : the control module 20 obtains steering information corresponding to the orientation of the steering wheel 24 from the steering device 21 via the rotation angle calculation module 60 .

In one embodiment, the step S20 may include the following steps S30-S31.

Step S30 : the control module 20 receives the steering coordinates (eg, the current position and attitude of the steering structure 30 ) provided by the steering sensing module 33 via the rotation angle calculation module 60 .

Step S31 : the control module 20 calculates the steering angle of the steering wheel 24 through the steering angle calculation module 60 according to the steering coordinates, and adds the steering angle to the steering information.

Step S21 : the control module 20 obtains the reference speed of the electric vehicle 2 through the speed calculation module 61 .

Step S22: The control module 20 calculates the left wheel reference speed and the right wheel reference speed through the speed calculation module 61, and sets the left drive control command and the right drive control command accordingly.

In one embodiment, referring to the above (Equation 1) and (Equation 2), the speed calculation module 61 can be based on the tangent or cotangent of the steering angle (ie, the reciprocal of the tangent, or can be equivalently replaced with other trigonometric functions) ), the reference speed of the electric vehicle 2 (or the current speed can be used), the length and wheelbase of the electric vehicle 2 to calculate the left wheel reference speed and the right wheel reference speed.

In one embodiment, step S22 may include the following steps S40-S43.

Step S40: The control module 20 determines the steering direction, such as left turn, right turn or straight ahead, through the turning angle calculation module 60 according to the turning information.

And, if it is a left turn or a right turn, steps S41-S43 are executed to establish the speed difference between the driving wheels; if it is a straight run, the establishment of the speed difference is skipped.

。 Step S41 : the control module 20 calculates the half-speed difference through the speed calculation module 61 according to the aforementioned (Formula 1) and (Formula 2), namely

.

Step S42: The control module 20 increases the reference speed (or current speed) of the electric vehicle 2 by the calculated half-speed difference via the speed calculation module 61 as one of the left wheel reference speed and the right wheel reference speed (ie, the outer For the driving wheels, the left driving wheel 25 is the right turning, and the right driving wheel 26 is the left turning, and the corresponding driving control command is set.

Step S43: The control module 20 reduces the reference speed (or current speed) of the electric vehicle 2 by the calculated half-speed difference through the speed calculation module 61 as the other (ie the inner side) of the left wheel reference speed and the right wheel reference speed. The driving wheel of 26 is the right driving wheel 26, and the left turning is the left driving wheel 25), and the corresponding driving control command is set.

Next, the control module 20 can execute steps S23-S26 to obtain the speed of each driving wheel and each motor.

Step S23 : the control module 20 senses the sensing data of the left motor 52 through the left motor sensor 53 via the left drive control module 620 .

Step S24 : the control module 20 calculates the current speed of the left drive wheel 25 through the left drive control module 620 according to the sensing data of the left motor 52 , eg, according to the current speed, gear ratio and wheel diameter.

Step S25 : the control module 20 senses the sensing data of the right motor 42 through the right motor sensor 43 via the right drive control module 621 .

Step S26 : the control module 20 calculates the current speed of the right driving wheel 26 through the right driving control module 621 according to the sensing data of the right motor 42 .

Step S27 : the control module 20 controls the speeds of the left driving module 22 and the right driving module 23 through the differential control module 63 according to the left driving control command and the right driving control command.

In one embodiment, step S27 may include steps S50 and S52, and steps S50 and S52 are used for precise speed control.

Step S50: The control module 20 continuously adjusts the speed of the left drive module 22 via the left speed control module 630 so that the current speed of the left drive wheel 25 conforms to the left wheel reference speed indicated by the left drive control command.

In one embodiment, the left speed control module 630 obtains the left current speed (left feedback speed) of the left drive module 22, and continuously adjusts the input to the left inverter according to the difference between the left feedback speed and the left wheel reference speed The left reference speed signal of module 51.

Step S52: The control module 20 continuously adjusts the speed of the right drive module 23 via the right speed control module 631 so that the current speed of the right drive wheel 26 conforms to the right wheel reference speed indicated by the right drive control command.

In one embodiment, the right speed control module 631 obtains the right current speed (right feedback speed) of the right driving module 23, and continuously adjusts the input to the right according to the difference between the right feedback speed and the right wheel reference speed. The signal of the right reference speed of the frequency conversion module 41 .

In one embodiment, step S27 may include steps S51 and S53, and steps S51 and S53 are used to perform more precise speed/torque control based on FOC. Moreover, the sensing data of the left motor 52 includes the rotational speed of the left motor 52 , and the sensing data of the right motor 42 includes the rotational speed of the right motor 42 .

Step S51 : the control module 20 adjusts the input voltage and input current of the left motor 52 by adjusting the PWM signal for the left motor 52 to adjust the rotational speed and/or torque of the left motor 52 through the left magnetic field guiding the control module 640 , and The sensing data of the left motor 52 is made to conform to the left reference rotational speed of the left drive control command.

In one embodiment, the left magnetic field guide control module 640 obtains the sensing data of the left motor 52 (left feedback data, such as the rotational speed data obtained through the Hall sensor), according to the difference between the left feedback data and the reference rotational speed of the left wheel. The difference between the two is used to continuously adjust the PWM signal input to the left motor 52 .

Step S53 : the control module 20 adjusts the input voltage and input current of the right motor 42 by adjusting the PWM signal for the right motor 42 through the right magnetic field guiding the control module 641 to adjust the rotational speed and/or torque of the right motor 42 , and The sensing data of the right motor 42 is made to conform to the right reference rotational speed of the right drive control command.

In one embodiment, the right magnetic field steering control module 641 obtains the sensing data (right feedback data) of the right motor 42, and continuously adjusts the input to the right motor according to the difference between the right feedback data and the reference speed of the right wheel 42 PWM signals.

Step S28 : the control module 20 determines whether the drive system is turned off, for example, the user turns off the power supply, completes parking, and the like.

If the system is turned off, the control is ended. Otherwise, steps S20-S27 are performed again to continuously monitor and control.

Thereby, the present invention can effectively realize the speed difference control of single control box and multiple motors.

Please refer to FIG. 7 , which is a circuit structure diagram of a driving system according to an embodiment of the present invention. Each functional block 701-725 can be hardware or software, which is not limited.

First, the steering information input 701 inputs the steering coordinate δ ^* , and the reference speed input 702 inputs the reference speed ω ^* to the Electronic Differential System (EDS) shown by the dotted line.

The steering angle calculation 704 and 705 calculate the corresponding steering angle according to the steering coordinate δ ^* , and input the corresponding steering angle to the combinations 706 and 707 respectively, so that the steering angle is combined with the reference speed ω ^* .

與右參考速度

。 Next, factor additions 708 and 709 respectively calculate and output the left reference speed based on the steering angle combined with the reference speed ω ^*

with right reference speed

.

與右參考速度

，並輸入至速度控制712、713。 Next, the speed feedbacks 710 and 711 respectively calculate a new left reference speed based on the left feedback speed _ωl and the right feedback speed _ωr

with right reference speed

, and input to speed control 712,713.

與右參考速度

轉換為類比的左參考速度控制訊號

與類比的右參考速度控制訊號

，並輸入至FOC 714、715。 The speed controls 712, 713 set the left reference speed

with right reference speed

Converted to analog left reference speed control signal

Right reference speed control signal with analog

, and input to FOC 714, 715.

The FOCs 714 and 715 respectively generate corresponding PWM signals according to the received signals, and input them to the separation and driving circuits 716 and 717 . In addition, the FOCs 714 and 715 can also obtain feedback rotational speeds from the Hall sensors 722 and 723 and perform vector control.

Separation and drive circuits 716, 717 pass frequency conversion processing 718 (including left frequency converters _T1L , _T2L , _T3L , _T4L , _T5L , _T6L , such as power crystal switches) and frequency conversion processing 719 (including right frequency converter _T1R ) , T _2R , T _3RL , T _4R , T _5R , T _6R , such as power crystal switches) change the input voltage and input current of the motors 720 and 721 , thereby changing the rotational speed and torque of the motors 720 and 721 .

In addition, the Hall sensors 722, 723 can continuously sense the sensing data of the motors 720, 721, and the left feedback speed ω _l and the right feedback speed ω _r are calculated according to the speed calculation 724, 725, for use as Speed feedback.

The present invention can realize stable steering and improve safety through electronic differential control.

The above description is only a preferred specific example of the present invention, and therefore does not limit the scope of the present invention. Therefore, all equivalent changes made by using the content of the present invention are all included in the scope of the present invention. Chen Ming.

2: Electric vehicle

20: Control Module

21: Steering device

22: Left drive module

23: Right drive module

24: steering wheel

25, 26: drive wheel

delta: steering information

Cl: Left drive control command

Cr: Right drive control command

Claims (18)

A drive system of an electric vehicle, comprising: a left drive module for providing power to a left drive wheel to control the rotation of the left drive wheel; a right drive module for providing power to a right drive wheel to Controlling the rotation of the right driving wheel; a steering device for receiving a steering operation to change the direction of a steering wheel, and for obtaining a steering information; and a control module electrically connected to the left driving module, the right driving module A drive module and the steering device, the control module is set to calculate a left drive control command and a right drive control command based on the steering information and a reference speed of the electric vehicle, and control the left drive through the left drive control command The speed of the drive module, and the speed of the right drive module is controlled by the right drive control command; wherein, during the steering process, the control module generates the left drive control command and the right drive control command with a speed difference , so that the electric vehicle can be steered stably by the speed difference between the left driving wheel and the right driving wheel. The drive system according to claim 1, wherein the steering device further comprises: a steering structure connected to the steering wheel and used to accept the steering operation to change the orientation of the steering wheel; a steering sensing module, electrically connected The control module is used for sensing a steering coordinate of the steering structure; a speed obtaining module is electrically connected to the control module for obtaining a current speed of the electric vehicle; and a speed control structure is electrically sexually connected to the control module for triggering a speed change signal based on a speed change operation; Wherein, the control module is set to determine the reference speed of the electric vehicle based on the speed conversion signal and the current speed; wherein, the control module further includes a rotation angle calculation module, and the rotation angle calculation module is set to A steering angle of the steering wheel is calculated based on the steering coordinates to be set as the steering information. The drive system of claim 1, wherein the left drive control command is used to set a left wheel reference speed, the right drive control command is used to set a right wheel reference speed, and the steering information includes a steering angle; wherein, The control module further includes a speed calculation module, the speed calculation module is set based on one of the tangent value or the cotangent value of the steering angle, the reference speed of the electric vehicle, the The length and a wheelbase between the left drive wheel and the right drive wheel are used to calculate the left wheel reference speed and the right wheel reference speed to set the left drive control command and the right drive control command. The drive system of claim 3, wherein the speed calculation module is set based on one of a tangent or a cotangent of the steering angle, the reference speed of the electric vehicle, and the length of the electric vehicle and the wheelbase to calculate a half speed difference, add the half speed difference to the reference speed of the electric vehicle as one of the left wheel reference speed and the right wheel reference speed, and set the corresponding left drive control command or the Right drive control command, reduce the reference speed of the electric vehicle by the half speed difference as the other of the left wheel reference speed and the right wheel reference speed, and set the corresponding left drive control command or the right drive control commands. The drive system of claim 1, wherein the left drive module comprises: a left motor, which transmits power to the left drive wheel through a left transmission structure; The left PWM signal adjusts the input voltage and input current of the left motor to adjust the torque of the left motor; and a left drive circuit is used to output the left PWM signal corresponding to a left reference speed; wherein, the right drive module include: A right motor transmits power to the right driving wheel through a right transmission structure; a right frequency conversion module is connected to the right motor for adjusting the input voltage and input current of the right motor based on a right PWM signal, so as to adjust the right motor torque of the motor; and a right drive module for outputting the right PWM signal corresponding to a right reference speed. The drive system of claim 1, wherein the left drive module includes a left motor sensor for sensing a sensing data of a left motor, and the right drive module includes a left motor sensor for sensing a right motor A right motor sensor for sensing data; wherein, the control module is electrically connected to the left motor sensor and the right motor sensor, and the control module includes: a left drive control module, which is set to calculate the current speed of the left drive wheel based on the sensing data of the left motor; and a right drive control module set to calculate the current speed of the right drive wheel based on the sensing data of the right motor. The drive system of claim 6, wherein the control module includes: a left speed control module configured to continuously adjust the speed of the left drive module so that the current speed of the left drive wheel conforms to the left drive a left wheel reference speed of the control command; and a right speed control module set to continuously adjust the speed of the right drive module so that the current speed of the right drive wheel conforms to a right wheel reference speed of the right drive control command . The drive system of claim 6, wherein the sensing data of the left motor includes the rotational speed of the left motor, and the sensing data of the right motor includes the rotational speed of the right motor; wherein the control module comprises: a The left magnetic field guide control module is set to adjust a PWM signal for the left motor to adjust the input voltage and input current of the left motor to adjust the rotational speed of the left motor and make the sensing data of the left motor match a left reference speed of the left drive control command; and A right magnetic field steering control module configured to adjust a PWM signal for the right motor to adjust the input voltage and input current of the right motor to adjust the rotational speed of the right motor and to make the sensing data of the right motor A right reference speed corresponding to the right drive control command. The drive system of claim 1, wherein the control module includes a speed calculation module, and the speed calculation module is configured to set a left wheel reference speed of the left drive control command when the steering information is a right turn A right wheel reference speed greater than the right drive control command, when the steering information is left turn, set the left wheel reference speed to be less than the right wheel reference speed, and when the steering information is straight, set the left wheel reference speed and the The speed difference between the reference speeds of the right wheels is less than 5%. The drive system of claim 1, wherein the steering wheel is a front wheel of the electric vehicle, and the left drive wheel and the right drive wheel are symmetrically arranged rear wheels of the electric vehicle; wherein the left drive module It includes a left motor, the right drive module includes a right motor, and the left motor and the right motor are permanent magnet synchronous motors; wherein, the electric vehicle is an electric tricycle. A drive control method, applied to a drive system of an electric vehicle, the drive system comprises a left drive module for driving a left drive wheel, a right drive module for driving a right drive wheel, A steering device for changing the orientation of a steering wheel, and a control module, the method comprising the steps of: a) obtaining a steering information corresponding to the orientation of the steering wheel through the steering device; b) obtaining the steering wheel from the control module a reference speed of the electric vehicle; c) calculating a left drive control command and a right drive control command based on the steering information and the reference speed of the electric vehicle; and d) controlling the left drive module through the left drive control command speed of the group, and control the speed of the right drive module through the right drive control command, wherein the left drive control command generated during the steering process And the right driving control command has a speed difference, so that the electric vehicle can be steered stably by the speed difference between the left driving wheel and the right driving wheel. The drive control method as claimed in claim 11, wherein the step a) comprises the following steps: a1) receiving a steering coordinate of the steering device at the control module; and a2) calculating a steering of the steering wheel based on the steering coordinate The angle to set as the steering information. The drive control method of claim 11, wherein the left drive control command is used to set a left wheel reference speed, the right drive control command is used to set a right wheel reference speed, and the steering information includes a steering angle; wherein The step c) includes the following steps: c1) Based on one of the tangent or cotangent of the steering angle, the reference speed of the electric vehicle, the length of the electric vehicle, and the left drive wheel and the right drive A wheelbase between wheels calculates the left wheel reference speed and the right wheel reference speed to set the left drive control command and the right drive control command. The drive control method as claimed in claim 13, wherein the step c) comprises the following steps: c11) based on one of the tangent value or the cotangent value of the steering angle, the reference speed of the electric vehicle, the electric vehicle Calculate the half speed difference from the length of the vehicle and the wheelbase; c12) increase the half speed difference to the reference speed of the electric vehicle as one of the left wheel reference speed and the right wheel reference speed, and set the corresponding left wheel drive control command or the right drive control command; and c13) reduce the reference speed of the electric vehicle by the half speed difference as the other of the left wheel reference speed and the right wheel reference speed, and set the corresponding left wheel drive control command or the right drive control command. The drive control method of claim 11, further comprising the steps of: e1) sensing a sensing data of a left motor of the left drive module through a left motor sensor; e2) based on the left motor Sensing data to calculate the current speed of the left drive wheel; e3) sensing a sensing data of a right motor of the right driving module through a right motor sensor; and e4) calculating the current speed of the right driving wheel based on the sensing data of the right motor. The drive control method of claim 15, wherein the step d) comprises the following steps: d1) continuously adjusting the speed of the left drive module, so that the current speed of the left drive wheel conforms to a left wheel of the left drive control command reference speed; and d2) continuously adjust the speed of the right drive module, so that the current speed of the right drive wheel conforms to a right wheel reference speed of the right drive control command. The drive control method of claim 15, wherein the sensing data of the left motor includes the rotational speed of the left motor, and the sensing data of the right motor includes the rotational speed of the right motor; the step d) includes the following steps: d3) Adjust the input voltage and input current of the left motor by adjusting a PWM signal for the left motor to adjust the rotational speed of the left motor, and make the sensing data of the left motor conform to a parameter of the left drive control command and d4) adjust the input voltage and input current of the right motor by adjusting a PWM signal for the right motor to adjust the rotation speed of the right motor, and make the sensing data of the right motor match the right motor A right reference speed for the drive control command. The drive control method as claimed in claim 11, wherein the step c) is when the steering information is a right turn, and a left wheel reference speed of the left drive control command is greater than a right wheel reference speed of the right drive control command, in When the steering information is left turn, the reference speed of the left wheel is less than the reference speed of the right wheel, and when the steering information is going straight, the speed difference between the reference speed of the left wheel and the reference speed of the right wheel is less than 5%.

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