Motor control device for electric motorcycle

Abstract

The invention relates to a motor control device of an electric motorcycle, which comprises a battery, a motor controller and a motor, and is characterized in that when the motor controller judges that the rotating speed of the motor is lower than a first preset rotating speed, the current of the battery is determined to be a first current; when the motor controller judges that the rotating speed of the motor is higher than a second preset rotating speed, the battery current is determined to be second current, the second preset rotating speed is higher than the first preset rotating speed, and the second current is smaller than the first current; the motor controller determines a current adjusting coefficient according to a battery voltage output by the battery, the battery current is multiplied by the current adjusting coefficient to obtain a driving current, and the motor controller supplies power to the motor through the driving current, so that the motor can output relatively high horsepower at different motor rotating speeds.

Description

Technical Field

[0001] This invention relates to a motor control device for an electric motorcycle, and more particularly to a control device capable of maintaining the motor's output power. Background Technology

[0002] Miniature or small light electric motorcycles on the market mainly use batteries as their power source. A motor controller inside the electric vehicle controls the battery current output, which drives a motor to generate power and move the electric vehicle.

[0003] These micro and small light electric motorcycles are subject to existing regulations that require the maximum output power of the motor to be controlled within a specified limit to restrict the vehicle's speed. For example, the maximum output power of the motor cannot exceed 1kW (1.34 horsepower). To ensure compliance with regulations, existing motor controllers control the battery current output at a fixed level. However, this results in reduced acceleration when the battery voltage is low. For instance, a battery with a rated voltage of 50.4V typically operates between approximately 42 and 57V. When the battery is at 57V, the motor output power can reach 1kW. However, when the battery voltage drops to 42V, if the same current is still output, the motor output power will only be about 0.72kW, equivalent to a reduction of 0.37 horsepower. Furthermore, while the motor may have 1kW of output power at high speeds, when climbing hills with the same battery current, the motor output will only be 0.47kW, equivalent to a reduction of 0.7 horsepower.

[0004] Because the battery current is maintained at a constant value, the motor's output power often falls below the specified value (e.g., 1kW) and cannot provide enough horsepower, making it easy for users to experience insufficient power when riding electric motorcycles. Summary of the Invention

[0005] [The technical problem that the invention aims to solve]

[0006] This invention addresses the problem that the motors of existing micro or small light electric motorcycles often fail to generate sufficient output power. Therefore, it proposes a motor control device for electric motorcycles that, under the premise of complying with relevant regulations, enables the motor to generate relatively high output power.

[0007] [Technical means to solve the problem]

[0008] To achieve the aforementioned objectives, the motor control device for the electric motorcycle of the present invention includes:

[0009] One battery, outputting one battery voltage and one battery current;

[0010] A motor controller is connected to the battery to detect the battery voltage;

[0011] A motor is connected to a motor controller and generates a motor speed, which is received by the motor controller.

[0012] Specifically, when the motor controller determines that the motor speed is lower than a first preset speed, it determines that the battery current is a first current; when the motor controller determines that the motor speed is higher than a second preset speed, it determines that the battery current is a second current, wherein the second preset speed is higher than the first preset speed and the second current is less than the first current.

[0013] The motor controller determines a current adjustment coefficient based on the battery voltage, and multiplies the determined battery current by the current adjustment coefficient to obtain a drive current. The motor controller then supplies power to the motor using this drive current.

[0014] [Effects of the invention]

[0015] When this invention is applied to electric motorcycles, when the motor speed of the electric motorcycle is relatively low (such as when climbing a hill), the motor controller of this invention increases the current supplied to the motor, so that the motor has a higher horsepower output and improves the climbing angle of the vehicle. Attached Figure Description

[0016] Figure 1 : Circuit block diagram of the motor control device for the electric motorcycle of the present invention.

[0017] Figure 2 : Control flowchart of the motor controller of this invention.

[0018] Figure 3 The diagram showing the relative relationship between battery current and motor speed in this invention.

[0019] Figure 4 The diagram showing the relative relationship between the current adjustment coefficient and the battery voltage in this invention.

[0020] Figure 5 The relationship curve between motor output power and motor speed in this invention and prior art.

[0021] List of reference numerals

[0022] 10: Battery

[0023] 20: Motor controller

[0024] 21: Current sensor

[0025] 22: Microprocessor

[0026] 23: Drive Circuit

[0027] 30: Motor

[0028] 31: Speed ​​sensor

[0029] Vo: Battery voltage

[0030] Io: Battery current

[0031] I1: First current

[0032] I2: Second current

[0033] V1: First operating voltage

[0034] V2: Second operating voltage

[0035] R: Motor speed

[0036] R1: First preset speed

[0037] R2: Second preset speed. Detailed Implementation

[0038] Please refer to Figure 1 As shown, the motor control device of the electric motorcycle of the present invention includes a battery 10, a motor controller 20 and a motor 30, wherein the motor controller 20 is electrically connected to the battery 10 and the motor 30.

[0039] The battery 10 outputs a battery voltage Vo and a battery current Io. The battery 10 has a rated voltage Vr, and the actual output battery voltage Vo will be between a first operating voltage V1 and a second operating voltage V2, where the second operating voltage V2 is higher than the first operating voltage V1. The rated voltage Vr is typically greater than the first operating voltage V1 and less than the second operating voltage V2. In this embodiment, taking a rated voltage Vr = 50.4 volts as an example, the actual output range of the first operating voltage V1 to the second operating voltage V2 is between 42 and 57 volts.

[0040] The motor controller 20 can obtain the battery voltage Vo and battery current Io of the battery 10, and can output a drive current to control the motor 30.

[0041] The motor controller 20 includes a current sensor 21, a microprocessor 22, and a drive circuit 23. The microprocessor 22 is electrically connected to the current sensor 21 and the drive circuit 23. The current sensor 21 senses the magnitude of the battery current Io and provides it to the microprocessor 22. The microprocessor 22 obtains the magnitude of the battery current Io through the current sensor 21 and can obtain the battery voltage Vo output by the battery 10 through a voltage detection circuit. The drive circuit 23 is used to drive the motor 30. In this embodiment, the drive circuit 23 is a three-phase drive circuit, which includes three bridge arms. Each bridge arm has an upper switch and a lower switch. The three bridge arms are respectively connected to the three-phase input terminals of the motor 30.

[0042] In this embodiment, the motor 30 is a hub motor, but other types of motors can also be used. The motor 30 is equipped with a speed sensor 31, such as a Hall sensor, which detects the rotational speed of the motor 30 and generates a speed signal. The microprocessor 22 receives the speed signal and obtains a motor speed R (rpm) of the motor 30 based on the speed signal.

[0043] In this invention, the motor controller 20 adjusts the battery current Io of the battery 10 based on the battery voltage Vo and the motor speed R, thereby increasing the output power of the motor 30 while still meeting a predetermined value, which is 1kW as an example. Please refer to... Figure 2 The control flow of the motor controller 20 is as follows:

[0044] S21: The motor controller 20 receives the motor speed R and the battery voltage Vo.

[0045] S22: The motor controller 20 determines whether the motor speed R is greater than 0; if the motor speed R is not greater than 0, the process ends; if the motor speed R is greater than 0, the subsequent process continues.

[0046] S23: The motor controller 20 determines the battery current Io that the battery 10 needs to output based on the motor speed R. Please refer to [reference needed]. Figure 3 As shown, the present invention first presets multiple speed values ​​for comparison, such as a first preset speed R1 and a second preset speed R2. The second preset speed R2 is greater than the first preset speed R1. In one embodiment, the first preset speed R1 is 210 rpm and the second preset speed R2 is 260 rpm. The actual preset speed values ​​can be adjusted according to the specifications of the electric motorcycle, the specifications of the motor, or relevant regulations, and are not particularly limited.

[0047] When the motor controller 20 determines that the motor speed R is lower than the first preset speed R1, the microprocessor 22 determines that the battery 10 needs to output a fixed first current I1, for example, the first current I1 is 25 amps. When the motor speed R is determined to be higher than the second preset speed R2, the microprocessor 22 determines that the battery 10 needs to output a fixed second current I2, for example, the second current I2 is 22 amps, which is less than the first current I1. When the motor speed R is between the first preset speed R1 and the second preset speed R2, the microprocessor 22 calculates the current that the battery 10 needs to output in a linear proportion between the first current I1 and the second current I2 based on the motor speed R. As the motor speed R increases, the battery current Io gradually decreases in a linear proportion. For example, when the motor speed R is 235 rpm, the battery current Io of the battery 10 is controlled to be 23.5 amps in a linear proportion.

[0048] S24: The motor controller 20 calculates a current adjustment coefficient based on the battery voltage Vo of the battery 10. Please refer to [reference needed]. Figure 4 As shown, since the battery voltage Vo output by the battery 10 is between the first operating voltage V1 and the second operating voltage V2, the present invention presets the current adjustment coefficient corresponding to the second operating voltage V2 to be "1", and the maximum current adjustment coefficient corresponding to the first operating voltage V1 is set to the ratio of the second operating voltage V2 to the first operating voltage V1 (i.e., V2 / V1). For example, in this embodiment, the current adjustment coefficient corresponding to the first operating voltage V1 is 57 / 42 = 1.36, i.e., 1.36. The microprocessor 22 in the motor controller 20 calculates a corresponding current adjustment coefficient based on the linear relationship of the battery voltage Vo of the battery 10, and this current adjustment coefficient is between 1 and (V2 / V1).

[0049] S25: The motor controller 20 multiplies the battery current Io determined in step S23 by the current adjustment coefficient calculated in step S24 to obtain a drive current. The motor controller 20 controls the drive circuit 23 to output the drive current to the motor 30, enabling the motor 30 to generate relatively high output power. Because the battery voltage of the battery 10 and the motor speed R of the motor 30 continuously change with the riding of the electric motorcycle, the above steps are performed continuously to adjust the output power of the motor 30 in real time.

[0050] Please refer to Figure 5 As shown, the solid line represents the relationship curve between the motor output power and the motor speed R of the present invention, while the dashed line represents the relationship curve between the motor output power and the motor speed R in the prior art. By comparing the two relationship curves, it can be clearly seen from the solid line curve that the present invention can improve the output power of the motor 30.

[0051] When the electric motorcycle's motor speed R is relatively low (such as during hill climbing), the motor controller 20 of this invention increases the current to give the motor 30 a higher horsepower output, thereby increasing the vehicle's climbing angle. When the motor speed R changes between the first preset speed and the second preset speed, the motor controller 20 adjusts the current in a linear proportion to avoid the user experiencing discomfort from sudden changes in power. On the other hand, when the battery voltage drops, this invention can use a current adjustment coefficient to increase the current supplied to the motor 30, so that the motor 30 can maintain sufficient horsepower output and avoid the user suddenly feeling that the electric motorcycle lacks power.

Claims

1. A motor control device for an electric motorcycle, characterized in that, Includes: One battery, outputting one battery voltage and one battery current; A motor controller is connected to the battery to detect the battery voltage; A motor is connected to the motor controller and generates a motor speed, the motor controller receiving the motor speed; Specifically, when the motor controller determines that the motor speed is lower than a first preset speed, it determines that the battery current is a first current; when the motor controller determines that the motor speed is higher than a second preset speed, it determines that the battery current is a second current, wherein the second preset speed is higher than the first preset speed and the second current is less than the first current. The motor controller determines a current adjustment coefficient based on the battery voltage, and multiplies the determined battery current by the current adjustment coefficient to obtain a drive current. The motor controller supplies power to the motor with the drive current.

2. The motor control device for the electric motorcycle according to claim 1, characterized in that, When the motor controller determines that the motor speed is between the first preset speed and the second preset speed, the motor controller determines the magnitude of the battery current based on the motor speed and the first current and the second current in a linear ratio. The higher the motor speed, the lower the battery current.

3. The motor control device for the electric motorcycle according to claim 1, characterized in that, The battery voltage is between a first operating voltage and a second operating voltage, wherein the second operating voltage is greater than the first operating voltage; The current adjustment coefficient corresponding to the second operating voltage is 1; The current adjustment coefficient corresponding to the first operating voltage is a maximum current adjustment coefficient, which is the ratio of the second operating voltage to the first operating voltage.

4. The motor control device for the electric motorcycle according to claim 3, characterized in that, Between the first operating voltage and the second operating voltage, the current adjustment coefficient changes linearly and proportionally, wherein the smaller the battery voltage, the larger the current adjustment coefficient.

5. The motor control device for an electric motorcycle according to claim 1, characterized in that, The motor controller includes: A current sensor is used to sense the magnitude of the battery current; A microprocessor is connected to the current sensor, compares the motor speed with the first preset speed and the second preset speed, and determines the current adjustment coefficient based on the battery voltage; A drive circuit is connected to the microprocessor and outputs the drive current to the motor according to the control of the microprocessor.

6. The motor control device for the electric motorcycle according to claim 1, characterized in that, The motor is equipped with a speed sensor to sense the motor speed. The speed sensor is connected to the motor controller and outputs a speed signal to the motor controller.

7. The motor control device for an electric motorcycle according to claim 1, characterized in that, The motor is a hub motor.

8. The motor control device for the electric motorcycle according to claim 3, characterized in that, The battery has a first operating voltage of 42 volts and a second operating voltage of 57 volts; a first preset rotation speed of 210 rpm and a second preset rotation speed of 260 rpm; a first current of 25 amps and a second current of 22 amps.

Images