TWI599161B - Motor and revolution speed control method thereof - Google Patents

Description

Motor and its speed control method

The present invention relates to a motor and a control method therefor; and more particularly to a motor and a method of controlling the same.

Conventional motors can convert electrical energy into power output, which can be used as a power source for devices such as fans. For example, a fan can be used to drive airflow through a fan to be used for air circulation or heat dissipation.

Taking a conventional fan motor as an example, a fan driver ASIC outputs a control signal to a motor coil, and an induction element (such as a Hall element) senses a state parameter of the motor operation to drive the rotor of the motor. And the output torque.

Please refer to FIG. 1 , which is a schematic diagram comparing the actual speed curve of the conventional motor with the ideal speed curve. Among them, as the duty cycle (DUTY CYCLE) of the control signal (such as PWM signal) increases, the ideal speed curve C1 of the motor has a linear trend, but the actual speed curve C2 of the motor has a nonlinear curve, and the actual speed curve C2 and The linear shape of the ideal speed curve C1 is inconsistent, so that the speed of the fan motor cannot be directly adjusted by the duty cycle, and an additional speed signal compensation circuit is needed to fine-tune the speed, which increases the cost and difficulty of the motor control.

In view of this, it is necessary to improve the shortcomings of the prior art described above to meet practical needs and improve its practicability.

The present invention provides a motor that tends to linearize the actual speed relationship curve to simplify the motor speed control process.

The invention further provides a motor speed control method, which can make the actual speed relationship curve of the motor tend to be linear, so as to simplify the motor speed control process.

The invention discloses a motor speed control method, which can be applied to a control unit for the control unit to regulate the rotation speed of a motor. The method may include: comparing, by the control unit, a voltage value of a reference signal and a voltage of an oscillation signal And generating a logic signal for controlling the rotation speed of the motor; wherein the voltage value of the reference signal is converted according to a duty cycle of the pulse width modulation signal, and the waveform of the oscillation signal has a charging period and a discharge The hold time of the discharge period is greater than the hold time of the charge period, and the time ratio of the discharge period to the charge period ranges from 1.1 to 4.

The present invention further discloses a motor, which may include: a stator having a coil module for driving a rotor to rotate; and a control unit electrically connected to the coil module, the control unit comparing a voltage value of a reference signal with A logic signal is generated to oscillate a signal to control a rotational speed of the rotor; wherein a voltage value of the reference signal is converted according to a duty cycle of a pulse width modulation signal, and the waveform of the oscillation signal has a waveform The charging period and a discharging period, the holding time of the discharging period is greater than the holding time of the charging period, and the time ratio of the discharging period to the charging period ranges from 1.1 to 4.

The control unit can determine whether the voltage value of the oscillation signal is less than the voltage value of the reference signal. If the determination is yes, the voltage value of the logic signal is a low level voltage. If the determination is no, the voltage value of the logic signal Is a high level voltage. Thereby, the user can adjust the degree of speed compensation to meet the actual running requirements of the motor.

The control unit may have a certain voltage output end, a base signal input end, an oscillating connection end and a speed control output port, and the constant voltage output end may be used to output a certain voltage, and the base signal input end may be used to input the reference signal The oscillating connection terminal can be used to input the oscillation signal, and the speed control The output coil is electrically connected to the coil module of the stator; the oscillating connection end is electrically connected to a capacitor to a ground end; and the current limiting output end and the oscillating connection end are electrically connected to a current limiting component The constant voltage output terminal and a signal input port are electrically connected to a signal converter. Thereby, the control unit can control the rotation speed of the motor according to the reference signal converted by the pulse width modulation signal.

The upper motor and the rotation speed control method thereof can simply change the time proportional range value of the discharge period and the charging period, for example, adjusting the resistance value of the current limiting component between the constant voltage output terminal and the capacitor, without additionally adding a rotation speed signal The compensation circuit can easily adjust the linearity of the actual speed curve of the motor. When the time ratio is 4, the actual speed curve of the motor exhibits the highest linearity, almost overlapping with the ideal speed curve, and can achieve the "reduced motor speed". The cost of control and the effect of reducing the complexity of motor speed control can be applied to various motor speed control circuits, such as fan speed control, which can further increase the demand for motor use.

[study]

C1‧‧‧ ideal speed curve of the motor

C2‧‧‧ actual speed curve of the motor

〔this invention〕

1‧‧‧Motor

11‧‧‧ Stator

111‧‧‧ coil module

2‧‧‧Control unit

21‧‧‧ Constant pressure output

22‧‧‧ basic input

23‧‧‧Oscillating connection

24‧‧‧Speed Control Output埠

3‧‧‧Signal Converter

4‧‧‧ capacitor

5‧‧‧ Current limiting components

A‧‧‧ source input埠

C‧‧‧ oscillation signal

E‧‧‧ logical signal

L‧‧‧ reference signal

P‧‧‧ pulse width modulation signal

T1‧‧‧Charging hours

T2‧‧‧ discharge time

Vcc‧‧‧ power supply

Actual speed curve of U1~U4‧‧‧ motor

Z‧‧‧The ideal speed curve of the motor

Fig. 1 is a schematic diagram showing the comparison between the ideal and actual rotational speed of a conventional fan motor.

Fig. 2 is a circuit diagram showing an embodiment of a motor system of the present invention.

FIG. 3 is a schematic diagram of signals according to an embodiment of the present invention.

Fig. 4 is a schematic view showing the comparison of different rotational speed curves of the motor of the embodiment of the present invention.

The above and other objects, features and advantages of the present invention will become more <RTIgt; Terms such as "before", "after", "left", "right", "upper (top)", "lower", "inside", "outside", "side", etc. The directional and directional terms are used to illustrate and understand the various embodiments of the present invention and are not intended to limit the invention.

Please refer to FIG. 2, which is a circuit diagram of an embodiment of a motor system of the present invention. The system embodiment may include a motor 1 and a control unit 2, and the control unit 2 is electrically connected to the motor 1 for outputting a signal to control the rotation speed of the motor 1, such as a rotation speed of the shaft when the motor 1 is running. The actual speed relationship curve of the motor 1 is made linear. The following examples illustrate its implementation, but not limited to this.

For example, the motor 1 can be composed of various inner or outer rotor motors suitable for a fan, such as a BLDC motor, etc., having a stator 11 having a stator 11 The coil module 111 is configured to drive a rotor (not shown) to rotate, so that the rotor can drive an impeller (not shown) to generate airflow. In addition, the control unit 2 can be a device having a motor control and driving function, such as a microcontroller (MCU), a digital signal processor (DSP) or a specific function integrated circuit (ASIC), etc., the control unit 2 can be pre-stored. a control logic (such as a hardware circuit or a software program) and the required data, the control unit 2 can be electrically connected to the coil module 111 of the stator 11, the control unit 2 can be powered by a power supply Vcc For controlling the rotational speed of the motor 1, the control unit 2 and its electrically connected electronic components are exemplified below. The electronic component and the control unit 2 can be integrated into a circuit board and become part of the internal components of the motor 1, but This is limited to this.

Referring to FIG. 2 again, the control unit 2 can have a certain voltage output terminal 21, a base signal input terminal 22, an oscillating connection terminal 23, and a speed control output port 24. The constant voltage output terminal 21 can be used to output a certain voltage, for example, 6 volts, etc., the constant voltage output terminal 21 can be electrically connected to a signal converter 3, and the signal converter 3 can be electrically connected to a source input port A, The signal input port A can output a pulse width modulation (PWM) signal P to the signal converter 3 (eg, a voltage dividing adjustment circuit), and the signal converter 3 can output the constant voltage of the constant voltage output terminal 21. According to the duty cycle of the pulse width modulation signal P (such as: 1~100%), different voltage division ratios are formed to generate a reference signal L, such as: 5 volts (constant voltage) × 50% (duty cycle) ) = 2.5 volts (the voltage value of the reference signal L), the voltage value of the reference signal L is a voltage range The value of the DC level voltage in the circumference (eg, 0 to 6 volts, etc.) is limited to this; in addition, the base signal input terminal 22 of the control unit 2 can be used to input the reference signal L as the control motor 1 The basis of the speed.

Referring to FIG. 2, the oscillating connection end 23 of the control unit 2 can be used to input an oscillating signal C or an output current. The oscillating connection end 23 can be electrically connected to a capacitor 4 to a ground end. 23 and the constant voltage output terminal 21 can be electrically connected to a current limiting component 5 (such as a resistor) for limiting the current output from the constant voltage output terminal 21 to the capacitor 4, when the electrical energy stored in the capacitor 4 When lower, the constant voltage output terminal 21 and the oscillating connection terminal 23 can be charged to the capacitor 4. When the capacitor 4 is filled with electric energy, the capacitor 4 can be discharged to the oscillating connection terminal 23, and the capacitor 4 is used to recharge the capacitor 4 The discharge signal can generate a continuous oscillation signal as the oscillation signal C. As shown in FIG. 3, the waveform of the oscillation signal C can have a charging period T1 and a discharging period T2, and the holding time of the discharging period T2 is greater than the charging period T1. The maintenance time, the time ratio range of the discharge period T2 and the charging period T1 may be between 1.1 and 4, such as: 1.1, 2, 3, 4, etc., the time proportional range value may be via the resistor of the current limiting element 5 The value is adjusted, such as: the constant pressure The output voltage of the output terminal 21 is 6 volts, and the voltage value of the oscillation signal C is between 1 and 4 volts. The resistance value of the current limiting element 5 can be selected from 300K Ω to 700 K Ω, but not limited thereto. The larger the resistance value of the flow element 5, the relative time value of the discharge period T2 of the oscillation signal C and the charging period T1 can be relatively increased. Thereby, the waveform of the oscillation signal C can be similar to the capacitance charging and discharging waveform between the sawtooth wave and the triangular wave, so as to form a signal with a motor speed compensation function, and the user can adjust the degree of the speed compensation as a control. The basis of the motor 1 speed is to meet the actual operation requirements.

Please refer to the second and third figures. The control logic of the control unit 2 can be used to compare the voltage value of the reference signal L with the voltage value of the oscillation signal C to generate a logic signal E, such as: the logic signal. E can be a pulse signal having a high and a low level, and the control unit 2 can determine whether the voltage value of the oscillation signal C is less than the voltage value of the reference signal L, and if it is determined to be "Yes", the voltage value of the logic signal E is a low level voltage (such as 0.5 volts, etc.). If the determination is "No", the voltage value of the logic signal E is a high level voltage (such as 3 volts, etc.) When the voltage value of the reference signal L is fixed at any voltage value within the voltage regulation range, the voltage value of the logic signal E can be directly adjusted by the ratio of the charging and discharging time of the oscillation signal C, so as to utilize The timing switching time of the logic signal E controls the rotation speed of the motor 1. For example, the logic signal E can control the time when the coil module 111 of the stator 11 supplies power to generate a magnetic force, and the rotation speed of the rotor is adjusted. However, the speed control output 24 of the control unit 2 can be electrically connected to the coil module 111 of the stator 11 for outputting the logic signal E to the coil module 111 as the motor 1 Speed control signal.

Please refer to FIG. 4, which is a schematic diagram of comparison of different speed curves of the motor of the embodiment of the present invention. Please refer to FIG. 3 together, wherein when the time ratio between the discharge period T2 and the charging period T1 is 1.1, 2, 3, and 4, respectively, the rotation speed curves of the motor 1 are U1, U2, and U3, respectively. U4, as can be seen from the figure, as the time ratio value gradually increases, the rotational speed curve of the motor 1 tends to be linear and not bent. In particular, when the time ratio value is 4, the rotational speed curve U4 of the motor 1 is presented. The degree of linearity is the highest and almost overlaps with the ideal speed curve Z of the motor. Therefore, in the embodiment of the present invention, by changing the time ratio of the discharge period T2 and the charging period T1, the actual speed curve of the motor can be finely adjusted according to the demand, and the linear speed is not required, and the motor speed can be reduced without additional speed signal compensation circuit. The cost and complexity of control.

The control unit 2 of the above embodiment of the present invention can compare the voltage value of the reference signal L with the voltage value of the oscillation signal C to generate the logic signal E for controlling the rotation speed of the motor 1; wherein the reference signal The voltage value of L is converted according to the duty cycle of the pulse width modulation signal. The waveform of the oscillation signal C has the charging period T1 and the discharging period T2, and the holding time of the discharging period T2 is greater than the holding time of the charging period T1. . In addition, the embodiment of the motor speed control method of the present invention can be applied to the control unit 2 for the control unit 2 to regulate the rotation speed of the motor 1. The step of: controlling the voltage of the reference signal L by the control unit 2 The value and the voltage value of the oscillation signal C generate the logic signal E for controlling the rotation speed of the rotor of the motor 1; wherein the voltage value of the reference signal L is converted according to the duty cycle of the pulse width modulation signal The waveform of the oscillation signal C has the charging period T1 and the discharging period T2, and the holding time of the discharging period T2 is greater than the holding time of the charging period T1.

Therefore, the above embodiment of the present invention can easily change the time proportional range value of the discharge period T2 and the charging period T1, for example, adjusting the resistance value of the current limiting element 5, and can be easily adjusted without additionally adding a speed signal compensation circuit. The linearity of the actual speed curve of the motor. When the time ratio is 4, the actual speed curve U4 of the motor 1 exhibits the highest degree of linearity, almost overlapping with the ideal speed curve, and can achieve the "cost of reducing the motor speed control" and The function of "reducing the complexity of motor speed control" can be applied to various motor speed control circuits, such as fan speed control, which can further increase the demand for motor use.

While the invention has been described in connection with the preferred embodiments described above, it is not intended to limit the scope of the invention. The technical scope of the invention is protected, and therefore the scope of the invention is defined by the scope of the appended claims.

C‧‧‧ oscillation signal

E‧‧‧ logical signal

L‧‧‧ reference signal

T1‧‧‧Charging hours

T2‧‧‧ discharge time

Claims (8)

A motor speed control method is applied to a control unit for the control unit to regulate the rotational speed of a motor. The method comprises the steps of: comparing, by the control unit, a voltage value of a reference signal and a voltage value of an oscillation signal to generate a a logic signal for controlling the rotation speed of the motor; wherein the voltage value of the reference signal is converted according to a duty cycle of a pulse width modulation signal, and the waveform of the oscillation signal has a charging period and a discharging period, and the discharging The hold time of the time period is greater than the hold time of the charge period, and the time ratio of the discharge period to the charge period ranges from 1.1 to 4. According to the motor speed control method of claim 1, wherein the control unit determines whether the voltage value of the oscillation signal is less than a voltage value of the reference signal, and if the determination is yes, the voltage value of the logic signal is a low level. The bit voltage, if the determination is no, the voltage value of the logic signal is a high level voltage. A motor comprising: a stator having a coil module for driving a rotor to rotate; and a control unit electrically connected to the coil module, the control unit comparing a voltage value of a reference signal with a voltage of an oscillation signal The value generates a logic signal for controlling the rotation speed of the rotor. The voltage value of the reference signal is converted according to a duty cycle of a pulse width modulation signal, and the waveform of the oscillation signal has a charging period and a discharge. The hold time of the discharge period is greater than the hold time of the charge period, and the time ratio of the discharge period to the charge period ranges from 1.1 to 4. The motor of claim 3, wherein the control unit determines whether the voltage value of the oscillation signal is less than a voltage value of the reference signal, and if the determination is yes, the voltage value of the logic signal is a low level voltage, If the determination is no, the voltage value of the logic signal is a high level voltage. The motor according to claim 3, wherein the control unit has a certain voltage output end, a base signal input end, an oscillating connection end and a speed control output port, wherein the constant voltage output end is used for outputting a certain voltage. The base signal input terminal is used for inputting the reference signal, and the oscillating connection end is used for inputting the oscillation signal, and the speed control output is electrically connected to the coil module of the stator. The motor of claim 5, wherein the oscillating connection is electrically connected to a capacitor to a ground. The motor of claim 6, wherein the constant voltage output end and the oscillating connection end are electrically connected to a current limiting element. The motor of claim 5, wherein the constant voltage output is electrically connected to a signal converter.