CN210363394U

CN210363394U - Protection system for overspeed operation of electric vehicle

Info

Publication number: CN210363394U
Application number: CN201920876510.3U
Authority: CN
Inventors: 黄昱仁; 纪顺得
Original assignee: Kwang Yang Motor Co Ltd
Current assignee: Kwang Yang Motor Co Ltd
Priority date: 2019-06-12
Filing date: 2019-06-12
Publication date: 2020-04-21
Anticipated expiration: 2029-06-12

Abstract

The utility model relates to an electric vehicle overspeed operation's protection system, include a battery, a motor and a control circuit, wherein the battery provides electric power supply electric vehicle and uses, the wheel that this motor is used for driving electric vehicle produces the operation, this battery of this control circuit electric connection and motor, when this control circuit judges the actual rotational speed of this motor and has been greater than a predetermined rated revolution, judge that this motor is overspeed operation, output a reverse magnetic field's electric current to the motor in order to reduce the back electromotive force of this motor promptly; the utility model discloses borrow by the back electromotive force who reduces the motor and play the protection efficiency, can avoid back electromotive force to cause unusual overcharge to the battery to reduce back electromotive force and trigger the battery protection mechanism and make whole car lose the probability of power, maintain electric vehicle's normal function.

Description

Protection system for overspeed operation of electric vehicle

Technical Field

The present invention relates to a control circuit of an electric vehicle, and more particularly to a protection system capable of reducing back electromotive force when the electric vehicle runs at an excessive speed.

Background

As the name implies, electric vehicles, such as electric motorcycles, use electric power as a power source of the vehicle, and generally, a battery is disposed on the vehicle, and the electric power of the battery is used to drive a motor of the vehicle to run, thereby driving the vehicle to move forward. Referring to fig. 4, a control circuit diagram of a conventional electric vehicle is shown, in which a control circuit 83 is disposed between a battery 81 and a motor 82 of the electric vehicle, the control circuit 83 can convert electric power in the battery 81 into a working power for driving the motor 82, and when the motor 82 is driven, the motor rotates to drive wheels to rotate through a transmission mechanism in the vehicle.

It is known that the motor 82 naturally generates a counter EMF (back EMF) when in operation, which increases as the speed of the motor 82 increases. In the case where the electric vehicle is normally running, when the back electromotive force of the motor 82 is equal to the voltage of the battery 81, it represents that the electric vehicle is at the maximum vehicle speed.

When the electric vehicle is subjected to an external force, the operation of the motor 82 may exceed the maximum rated rotation speed and the back electromotive force increases, for example, when the vehicle is dragged or the downhill distance is long, the speed is fast, and the like, the motor 82 may be driven by the external force to run over speed, and the motor 82 is equivalent to a generator. Since the back electromotive force of the motor 82 is already higher than the voltage of the battery 81, a charging current is generated due to the voltage difference relationship to directly charge the control circuit 83 and the battery 81. When the motor 82 runs at an excessive speed and the back electromotive force is abnormally increased, the electric vehicle may have the following problems:

first, when the motor 82 is turned into a generator, excessive charging current or back emf may burn the battery 81 and the control circuit 83 or reduce the life of the battery 81.

Second, since a protection switch 810 is usually connected to the battery 81, when the control circuit 83 detects a charging current rise, it may trigger a protection mechanism, and open the protection switch 810 to interrupt the connection between the battery 81 and the controller 83. However, once the battery 81 is disconnected from the control circuit 83, the entire electric vehicle loses power instantaneously, causing inconvenience or even accidents to the rider.

Third, when the trigger protection mechanism disconnects the battery 81 from the control circuit 83, the battery 81 will no longer absorb power and lose the buffering effect on the back electromotive force, in other words, the back electromotive force or the charging current will be pulled up rapidly to burn out the electronic components in the control circuit 83.

SUMMERY OF THE UTILITY MODEL

[ problem to be solved by the utility model ]

The utility model provides an electric vehicle that can effectively reduce back electromotive force hypervelocity moving protection system to the motor among the solution electric vehicle leads to the problem that back electromotive force risees unusually because of speeding the operation.

[ MEANS FOR SOLVING PROBLEMS ] A method for producing a semiconductor device

In order to achieve the above object, the present invention provides a protection system for over-speed operation of an electric vehicle, comprising:

a battery for providing power for the electric vehicle;

a motor for driving the wheels of the electric vehicle to run;

and the control circuit is electrically connected with the battery and the motor and used for driving the motor, wherein when judging that the actual rotating speed of the motor is greater than a preset rated rotating speed, the control circuit outputs a current of a reverse magnetic field to the motor so as to reduce the counter electromotive force of the motor.

Further, the control circuit comprises:

a processor;

the driving unit is electrically connected with the processor and the battery and drives the motor by the processor;

and the internal of the memory is defaulted with the battery voltage and the rated rotating speed respectively corresponding to the battery voltage.

Further, the processor is connected with an accelerator opening sensor to receive an accelerator opening value; when the actual rotating speed of the motor is larger than the preset rated rotating speed, the processor enables the throttle opening value to return to zero, and the output power of the motor is enabled to be zero.

Further, the driving unit includes a plurality of power transistors for converting the power of the battery into three-phase voltages and supplying the three-phase voltages to the motor.

Further, at least one rotating speed sensing component is arranged inside the motor to sense the actual rotating speed of the motor, and the actual rotating speed is provided to the processor.

Further, the rotating speed sensing assembly is a Hall assembly.

Further, the control circuit is electrically connected to a display instrument of the electric vehicle, wherein when the control circuit determines that the actual rotation speed of the motor is greater than the preset rated rotation speed, the control circuit commands the display instrument to display a warning message.

Further, the warning message displayed by the display instrument is at least one of a pattern symbol, a code or a slogan character.

Further, the battery is connected with a protection switch.

Further, the protection switch is a relay or a MOS transistor component.

[ MEANS FOR UTILITY ] of the utility model

By the technical means of the utility model, when the motor runs at an overspeed, the control circuit outputs the current of the reverse magnetic field to the motor to weaken the counter electromotive force of the motor, thereby avoiding the battery triggering protection mechanism from causing the whole electric vehicle to lose power; and can prevent the excessive charging current from generating to overcharge the battery, therefore can lengthen the battery life; the possibility that the control circuit is damaged by high voltage due to the overhigh back electromotive force is reduced.

Drawings

FIG. 1: the electric vehicle overspeed operation protection system is a circuit schematic diagram.

FIG. 2: schematic diagram of the protection switch.

FIG. 3: a schematic diagram of the meter is displayed.

FIG. 4: the control circuit block diagram of the electric vehicle in the prior art.

[ description of reference ]

10 battery 11 protection switch

20 motor 21 rotational speed sensing assembly

30 control circuit 31 processor

32 drive unit 33 memory

34 accelerator opening sensor 40 display instrument

81 battery 810 protection switch

82 motor 83 control circuit

Q1-Q6 power transistor

Detailed Description

Referring to fig. 1, the present invention is a protection system for an electric vehicle, such as an electric motorcycle, including a battery 10, a motor 20 and a control circuit 30.

The battery 10 is used for providing the electric power required by the electric vehicle, and the battery 10 may be further connected to a protection switch 11, wherein the protection switch 11 may be a relay or a connection of MOS transistor components shown in fig. 2.

The motor 20 is connected to the control circuit 30, the motor 20 may be a permanent magnet synchronous motor for driving the wheels of the electric vehicle to drive the vehicle to move forward, and at least one rotation speed sensing component 21 is disposed in the motor 20 for sensing the actual rotation speed of the motor 20 during operation. In the embodiment, three hall elements are provided to sense the rotation speed of the motor 20, and the rotation speed signals generated by the three hall elements are provided to the processor 31 in the control circuit 30, so that the processor 31 can obtain the real-time rotation speed, and accordingly, it is determined whether the protection function needs to be started or not

The control circuit 30 is connected to the battery 10, in this embodiment, the control circuit 30 includes a processor 31, a driving unit 32, a memory 33, and an accelerator opening sensor 34; the processor 31 is connected to the driving unit 32, the memory 33 and the accelerator opening sensor 34, the driving unit 32 is connected to the battery 10 and includes six power transistors Q1-Q6, the on and off operations of the six power transistors Q1-Q6 are controlled by respective control signals output by the processor 31, and the power of the battery 10 can be converted into three-phase voltage U, V, W and supplied to the motor 20; the memory 33 is configured to default a relationship table of battery voltage to rated rotation speed, that is, the maximum rotation speed (rpm) that the motor 20 can output under what voltage the battery 10 is, for example, when the voltage of the battery 10 is 40V, 50V, and 60V, respectively, the rated rotation speeds of the motor 20 are 400rpm, 500rpm, and 600rpm, respectively. The accelerator opening sensor 34 senses an accelerator opening value outputted when the user operates the handle of the electric vehicle, and the accelerator opening value is provided to the processor 31, so that the processor 31 determines the vehicle speed according to the accelerator opening value.

The control circuit 30 can be further connected to a display instrument 40 of the electric vehicle, as shown in fig. 3, the display instrument 40 can display status information of the electric vehicle, such as electric quantity, real-time vehicle speed, accumulated mileage, etc., in the present invention, a warning message can be displayed.

The specific circuit operation of the present invention is described in further detail below: when the electric vehicle is running, the rotation speed sensing assembly 21 inside the motor 20 continuously senses the actual rotation speed of the motor 20 and generates a rotation speed signal, which is provided to the processor 31 for determination. Based on the default relationship between the battery voltage and the rated rotation speed in the memory 33, the processor 31 determines the corresponding rated rotation speed according to the voltage of the battery 10, compares the sensed actual rotation speed with the corresponding rated rotation speed, and determines that the motor 20 is currently in the overspeed operation when the actual rotation speed is greater than the rated rotation speed, wherein when the processor 31 selects the rated rotation speed, the corresponding rated rotation speed is selected according to the current real-time voltage of the battery 10, for example, when the voltage of the battery 10 is 50V, the selected rated rotation speed is 500rpm, and when the voltage drop of the battery 10 is 40V, the selected rated rotation speed is 400 rpm.

Once the motor 20 is determined to be running at an overspeed, the processor 31 first returns the throttle opening value output by the throttle opening sensor 34 to zero, so as to make the output power of the motor 20 zero, and then performs a field weakening operation through the driving unit 32, that is, controls the driving unit 32 to inject a current capable of generating a reverse magnetic field into the motor 20, so as to reduce the back electromotive force generated by the motor 20.

In addition, when the motor 20 is determined to be running at an overspeed, the processor 31 may further control the display instrument 40 to display a warning message to remind the user to manually start the braking function, wherein the displayed warning message may be a pattern symbol, a code, a slogan character, or other forms for the user to recognize. When the processor 31 determines again that the actual rotation speed of the motor 20 is lower than the rated rotation speed, the display instrument 40 is controlled not to display the warning message.

To sum up, the utility model discloses when motor 20 runs at an excessive speed, this drive unit 22 of this drive unit 22 output reverse magnetic field's electric current to motor 20 is controlled promptly to weaken motor 20's back electromotive force, consequently, the utility model discloses can reach following efficiency:

firstly, the battery 10 is prevented from triggering a protection mechanism to cause the whole electric vehicle to lose power, and inconvenience or accidents caused to a rider are reduced.

Second, since the generation of an excessive charging current can be prevented from overcharging the battery 10 due to the reduction of the counter electromotive force, the battery life can be extended.

And thirdly, damage to the control circuit 30 caused by the overhigh counter electromotive force or charging current is avoided, and the possibility that each electronic component in the control circuit 30 is subjected to high-voltage breakdown due to the overhigh counter electromotive force is reduced.

Fourthly, when the control circuit 30 judges that the actual rotating speed of the motor 20 is greater than the preset rated rotating speed, the control circuit 30 controls the display instrument 40 to display a warning message, such as displaying a pattern symbol, a code or a slogan character, and the warning message can remind a user of the abnormal vehicle state, and the user can immediately take emergency treatment, such as manually starting a brake function to slow down the vehicle speed, so as to avoid harm caused by the excessively fast vehicle speed, and ensure the driving safety of the user.

Although the present invention has been described with reference to the preferred embodiments, it is not intended to limit the present invention, and various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the present invention.

Claims

1. A protection system for over-speed operation of an electric vehicle, comprising:

a battery providing electrical power for use by the electric vehicle;

a motor for driving the wheels of the electric vehicle to run;

and the control circuit is electrically connected with the battery and the motor and used for driving the motor, wherein when the control circuit judges that the actual rotating speed of the motor is greater than a preset rated rotating speed, the control circuit outputs a current of a reverse magnetic field to the motor so as to reduce the counter electromotive force of the motor.

2. The system of claim 1, wherein the control circuit comprises:

a processor;

the driving unit is electrically connected with the processor and the battery, and the processor controls the motor;

3. The system of claim 2, wherein the processor is further coupled to a throttle opening sensor to receive a throttle opening value; and when the actual rotating speed of the motor is greater than the preset rated rotating speed, the processor enables the throttle opening value to return to zero, so that the output power of the motor is zero.

4. The system of claim 2, wherein the driving unit comprises a plurality of power transistors for converting the power of the battery into three-phase voltage and supplying the three-phase voltage to the motor.

5. The protection system for electric vehicle overspeed operation of claim 2, wherein at least one speed sensing assembly is disposed within said motor to sense an actual speed of rotation of said motor, said actual speed of rotation being provided to said processor.

6. The protection system for electric vehicle overspeed operation of claim 5 wherein said speed sensing assembly is a Hall assembly.

7. The system of claim 1, wherein the control circuit is further electrically connected to a display instrument of the electric vehicle, wherein the control circuit causes the display instrument to display a warning message when the control circuit determines that the actual speed of the motor is greater than the predetermined rated speed.

8. The system of claim 7, wherein the warning message displayed by the display meter is at least one of a graphical symbol, a code, or a slogan text.

9. The system of claim 1, wherein the battery is connected to a protection switch.

10. The system of claim 9, wherein the protection switch is a relay or a MOS transistor device.