TWM461937U - Motor driving device with minimum speed setting - Google Patents

Description

Motor drive with minimum speed setting

The present invention relates to a motor drive device, and more particularly to a motor drive device having a minimum speed setting; the motor drive device having the lowest speed setting can be used to adjust different motor speed curves and can be used to set the motor. The minimum speed, which in turn achieves the function of changing the motor speed and maintaining the minimum operating torque of the motor.

Traditionally, Pulse Width Modulation (PWM) is used to control the motor drive. It is impossible to achieve the adjustable speed curve. It is based on the input duty cycle (Duty cycle), which corresponds to the motor output speed. How many. For example, please refer to FIG. 1 , which is a schematic diagram of the output curve of a conventional pulse width modulation control motor drive. As shown in FIG. 1 , the duty cycle of the PWM is 0% to 100%, and the duty cycle of the PWM is 50%. At the same time, the corresponding motor will output 50% of the speed, so the control curve of the motor speed will show a linear curve.

Generally, under the same motor load, in order to achieve the minimum heat dissipation requirement and reduce the noise and noise generated by the motor restart, it is usually necessary to fix the motor at a speed after the PWM duty cycle is low to a certain value, not because of the PWM duty cycle. The output is less than the minimum operating torque of the motor, causing the motor to stop rotating.

However, when the user wants to change the speed of the motor according to the actual operating state, it usually changes the PWM duty cycle of the input or changes the coil design of the motor. However, the above two methods have practical difficulties. For example, when you want to change the PWM duty cycle of the controller input with the actual operating conditions, you must change the control mode of the whole system; if you want to change the coil of the motor, you must replace the motor.

Therefore, this creation provides a motor drive with the lowest speed setting, except through Adjust the voltage between the adjustable maximum set voltage signal (VH), the adjustable minimum set voltage signal (VL) and the triangle wave signal (TRI), and adjust the minimum speed setting voltage signal to keep the motor working at the lowest level. Torque to maintain minimum heat dissipation allows the motor drive to have the ability to change motor speed and the lowest speed setting to increase motor flexibility.

In order to solve the above problems, one of the main purposes of the present invention is to provide a motor driving device with a minimum speed setting, which first inputs an adjustable maximum set voltage signal (VH) and an adjustable minimum set voltage signal through a PWM conversion circuit ( VL) and the control signal are converted into analog signal (VTH), and then the analog signal converted by the PWM conversion circuit is input together with a triangular wave signal (TRI) generated by an oscillation circuit and an adjustable minimum speed setting voltage signal. After comparing to the comparator, an output driving signal is generated, and the output driving signal is sent to the control unit to control the rotation speed of the motor. Therefore, the present invention can use the motor drive device to adjust different motor speed curves and can be used to set the minimum motor speed, thereby achieving the function of changing the motor speed and maintaining the minimum working torque of the motor, and increasing the flexibility of the motor control.

According to the above items, the present invention provides a motor driving device having a minimum speed setting, comprising: a PWM conversion circuit having a first input terminal, a second input terminal, a third input terminal, and an output terminal. The first input terminal is connected to a control signal, the second input terminal is connected to an adjustable maximum set voltage signal (VH), and the third input terminal is connected to an adjustable minimum set voltage signal (VL), and is outputted by the output terminal. a type of ratio signal (VTH), wherein the analog signal can be changed by adjusting the control signal, the adjustable maximum set voltage signal (VH) or the adjustable minimum set voltage signal (VL); an oscillating circuit is used To generate a triangular wave signal (TRI); and a comparator having a first input terminal, a second input terminal, a third input terminal, and an output terminal, wherein the first input terminal and the triangular wave signal generated by the oscillating circuit Connected, the second input is connected to the analog signal output by the PWM conversion circuit, and the third input receives an adjustable minimum speed Set the voltage signal and output a drive signal from the output.

The motor drive device with the lowest speed setting provided by the present invention causes the motor drive device to generate an analog signal by adjusting the control signal, adjusting the maximum set voltage signal (VH), and adjusting the minimum set voltage signal (VL). And comparing the signal with the triangular wave signal (TRI) and one of the adjustable minimum speed setting voltage signals to the comparator for comparison and generating a driving signal, thereby driving the signal to control different motor speed curves. In addition to the function of changing the motor speed, the motor drive device of the present invention can maintain the minimum working torque of the motor, thereby increasing the flexibility of the motor application.

Since the present invention mainly discloses a motor driving device with a minimum speed setting, the input adjustable adjustable maximum voltage signal (VH), adjustable minimum set voltage signal (VL) and control signal are converted into analog signals through a PWM conversion circuit. (VTH), and then input the analog signal with the triangular wave signal (TRI) generated by the oscillating circuit and an adjustable minimum speed setting voltage signal to the comparator for comparison to generate an output driving signal, and then The output drive signal is sent to the control unit to control the speed of the motor. The basic principles and functions of the motor related to the present invention have been known to those skilled in the relevant art, so that the description of the motor drive device and its driving method will be described in detail in the following description. . In addition, the drawings in the following texts are not completely drawn according to the actual relevant dimensions, and their functions are only to express the schematic diagrams related to the present creative features.

First, please refer to FIG. 2, which is a schematic diagram of the motor drive device architecture of the present invention. As shown in FIG. 2, the motor driving device includes: a PWM conversion circuit 10 having a first input terminal, a second input terminal, a third input terminal, and an output terminal, wherein the first input terminal and a control signal 101 Connected, the second input terminal is connected to an adjustable maximum set voltage signal (VH) 102, and the third input terminal is connected to an adjustable minimum set voltage signal (VL) 103, and the output terminal outputs a analog signal (VTH). The control signal is a PWM signal (for example: one provided by a personal computer system) PWM signal), and the analog signal can be changed by adjusting the control signal, the adjustable maximum set voltage signal (VH) or the adjustable minimum set voltage signal (VL); an oscillating circuit 12 is used to generate a triangular wave signal (TRI), wherein the triangular wave signal is adjustable between a high voltage level and a low voltage level; a comparator 14 having a first input, a second input, and a third input And an output end, wherein a first input end is connected to a triangular wave signal (TRI) generated by the oscillation circuit 12, and a second input end is connected to the analog signal (VTH) outputted by the PWM conversion circuit 10, The three input terminal receives an adjustable minimum speed setting voltage signal 141, and outputs a driving signal (S_DR) from the output terminal; and a control unit 16 is configured to receive the driving signal (S_DR) to control a motor 18, wherein the motor It is a single phase motor or a three phase motor.

Next, please refer to FIG. 3, which is a PWM conversion circuit diagram of the present creation. As shown in FIG. 3, the PWM conversion circuit 10 has a first input terminal, a second input terminal, a third input terminal, and an output terminal. The first input terminal is connected to a control signal 101, and the second input terminal is coupled to the second input terminal. An adjustable maximum set voltage signal (VH) 102 is connected, and the third input end is connected to an adjustable minimum set voltage signal (VL) 103, and the output end outputs a analog signal (VTH), wherein the control signal is one a PWM signal (for example, a PWM signal provided by a personal computer system), and the analog signal can be adjusted by adjusting the control signal, the adjustable maximum set voltage signal (VH) or the adjustable minimum set voltage signal (VL) The PWM conversion circuit further includes a first operational amplifier (OP1) having a positive input electrically coupled to the adjustable maximum set voltage signal 102, a negative input, and an output electrically coupled to the negative input. a second operational amplifier (OP2) having a positive input electrically coupled to the adjustable minimum set voltage signal 103, a negative input, and an output electrically coupled to the negative input; a first switching component (TG1), with The input end of the first input signal is coupled to the first operational amplifier (OP1), coupled to an output of one of the output nodes (VA), coupled to one of the control terminals of the control signal 101, and coupled to the first a connection terminal of the common node (N), the first switching element (TG1) determines whether to turn on the first input signal according to the control signal 101, wherein the first switching element (TG1) is a transmission gate; and the second switching element (TG2) having an input for receiving a second input signal The second operational amplifier (OP2) is coupled to one of the outputs of the output node (VA), the control terminal coupled to one of the control signals 101, and the one coupled to the common node (N). The second switching element (TG2) determines whether to turn on the second input signal according to the control signal 101, wherein the second switching element (TG2) is a transmission gate; and an inverter 20 has an input terminal for receiving the control signal. 101, wherein the output is connected to the common node (N); and a low pass filter circuit 22 for converting a voltage generated by the output node (VA) into an analog signal (VTH), wherein the low pass filter circuit The 22 series is a second-order low-pass filter circuit, further comprising a first resistor (R1) having a first end coupled to the output node (VA) and a second end; a second resistor (R2), a first end coupled to the second end of the first resistor (R1) and a second end; a first capacitor (C1) having a first end coupled to the second resistor (R2), And a second terminal coupled to the ground; a third operational amplifier (OP3) having a positive input electrically coupled to the second resistor (R2) a contact between the first capacitor (C1), a negative input terminal, and an output terminal electrically connected to the negative input terminal for outputting an analog signal (VTH); and a second capacitor (C2) having a first One end is coupled to a junction between the first resistor (R1) and the second resistor (R2), and a second end is coupled to the output end of the third operational amplifier (OP3).

After the control signal 101 is input to the PWM conversion circuit 10 via the first input terminal of the PWM conversion circuit 10, the adjustable maximum set voltage signal (VH) 102 and the PWM conversion circuit can be input through the second input terminal of the PWM conversion circuit 10. The third input terminal of 10 inputs an adjustable minimum set voltage signal (VL) 103 to convert into a analog signal (VTH), wherein the control signal 101 is a PWM signal, and the duty cycle can be from 0% to 100%. The change, and the adjustable maximum set voltage signal (VH) 102 and the adjustable minimum set voltage signal (VL) 103 can be set via an external input. After the external input setting is completed, the adjustable maximum set voltage signal (VH) 102 is input to the positive input terminal of the first operational amplifier (OP1), and the first operational input is output through the first operational amplifier (OP1). The signal is input to the first switching element (TG1); the adjustable minimum set voltage signal (VL) 103 is input to the positive input terminal of the second operational amplifier (OP2), and is output through the second operational amplifier (OP2). The terminal outputs the second input signal to the second switching element (TG2) The control signal 101 is connected to the input end of the inverter 20, the control end of the first switching element (TG1), and the control end of the second switching element (TG2), and the control signal 101 is used to adjust the maximum setting. The voltage signal (VH) 102 is output to the output node (VA) through the first operational amplifier (OP1), or the adjustable minimum set voltage signal (VL) 103 is output to the output node through the second operational amplifier (OP2). (VA), and then converted to an analog signal (VTH) by the adjustable maximum set voltage signal (VH) 102 or the adjustable minimum set voltage signal (VL) 103 sampled by the output node (VA) via a low pass filter circuit 22. It is output to the comparator 14, which in turn controls the motor 18.

Next, please refer to FIG. 4 and cooperate with FIG. 3, which is a schematic diagram of the converted analog signal (VTH) output result of the present creation. As shown in FIG. 4, the analog signal (VTH) controls the adjustable maximum set voltage signal (VH) or the adjustable minimum set voltage signal (VL) through the control signal 101 to output to the output node (VA), and converts and outputs the same. The analog signal (VTH) is converted by a conversion formula. The conversion formula is as shown in the following equation (1): VTH = (VH - VL) × control signal its duty cycle (Duty cycle) + VL (1) However, the setting is different. The adjustable maximum set voltage (VH) or the adjustable minimum set voltage signal (VL) is converted by the conversion formula to produce different analog signal (VTH) results. For example, if the duty cycle of the input control signal is fixed to 20%, the duty cycle of the PWM signal is fixed to 20%, and the adjustable maximum set voltage signal (VH) is observed. ) or adjust the analog signal (VTH) generated by the lowest set voltage signal (VL); for example, when the adjustable maximum set voltage signal (VH) = 5V and the adjustable minimum set voltage signal (VL) = 0V, After the conversion formula is converted, an analog signal (VTH)=1V can be generated; when the adjustable maximum set voltage signal (VH)=3.75V and the adjustable minimum set voltage signal (VL)=1.25V are set, the conversion formula can be generated after conversion. The analog signal (VTH)=1.75V; when the adjustable maximum set voltage signal (VH)=3V and the adjustable minimum set voltage signal (VL)=1.5V, the analog signal (VTH) can be generated after conversion by the conversion formula. =1.8V. If the duty cycle (ie, PWM signal) of the input control signal is fixed to 60%, observe the setting of different adjustable maximum set voltage signal (VH) or adjustable minimum set voltage signal (VL). Analog signal (VTH), for example: when setting the adjustable maximum When the constant voltage signal (VH)=5V and the adjustable minimum set voltage signal (VL)=0V, the analog signal (VTH)=3V can be generated after conversion formula conversion; when the adjustable maximum set voltage signal (VH)=3.75 is set V, adjustable minimum set voltage signal (VL) = 1.25V, after conversion formula can generate analog signal (VTH) = 2.75V; and when set adjustable maximum set voltage signal (VH) = 3V, adjustable minimum When the voltage signal (VL)=1.5V is set, the analog signal (VTH)=2.4V can be generated after conversion by the conversion formula. According to the above, when the control signal (ie, the PWM signal) changes its duty cycle from 0% to 100%, different adjustable maximum set voltage signals (VH) or adjustable minimum set voltage signals are set ( VL), the result of the analog signal (VTH) produced by the conversion formula will show a linear change. However, by adjusting the control signal, the adjustable maximum set voltage signal (VH) or the adjustable minimum set voltage signal (VL) can be used to change the analog signal, and then generate the analog signal and the triangular wave signal generated by the oscillating circuit 12 (TRI) The comparison produces a drive signal, and the drive signal is used to generate different output speed ratios (Duty%) to control the motor rotation, which can change the motor speed.

Therefore, please refer to FIG. 5A first, which is a waveform diagram of the first embodiment of the present invention. As shown in FIG. 5A, in the first embodiment, the high voltage of the triangular wave signal (TRI) is fixed to 3.75V, the low voltage is fixed to 1.25V, and the adjustable maximum set voltage signal (VH) is fixed at 3.75V to adjust. The adjustable minimum set voltage signal (VL) is compared with the triangular wave signal (TRI) by the analog signal (VTH) generated by the conversion formula conversion, and the output signal is observed to control the motor output speed; therefore, it is further divided into three states. Explain the result of the comparison: the original state (ORG) represents the state of VH=3.75V, VL=1.25V, the state 1 (CASE1) represents the state of VH=3.75V, VL=0V, and the state 2 (CASE2) represents VH =3.75V, VL=2.25V state; first, assume that in the state of the original state (ORG), the high voltage of the triangular wave signal (TRI) is fixed at 3.75V, and the low voltage is fixed at 1.25V, which will be adjusted to the highest setting. The voltage signal (VH) is fixed at 3.75V, and the adjustable minimum set voltage signal (VL) is set to 1.25V. The result of the analog signal (VTH) generated by the conversion formula conversion will vary from 1.25V to 3.75V. Compare it with the high voltage and low voltage of the triangular wave signal (TRI) and observe the output signal. The raw results of FIG. 5A original state (the ORG) The waveform diagram, because the result of the analog signal (VTH) is consistent with the high voltage and low voltage of the triangular wave signal (TRI), the output speed will change linearly. Secondly, it assumes the state of the state 1 (CASE1). The high voltage of the signal (TRI) is fixed at 3.75V, the low voltage is fixed at 1.25V, the adjustable maximum set voltage signal (VH) is fixed at 3.75V, and the adjustable minimum set voltage signal (VL) is changed to 0V. The result of the analog signal (VTH) generated after the conversion formula conversion will vary from 0V to 3.75V, compare it with the high voltage and low voltage of the triangular wave signal (TRI) and observe the output signal. The result is shown in the figure. 5A state 1 (CASE1) waveform diagram, since the analog signal (VTH) starts from 0V, when the analog signal (VTH) changes to 1.25V, it will contact with the triangle wave signal (TRI). The speed, therefore, the analog signal (VTH) has no output speed at 0V to 1.25V; secondly, under the state 2 (CASE2), the high voltage of the triangular wave signal (TRI) is fixed at 3.75V, and the low voltage is fixed at 1.25V, fixed adjustable maximum voltage signal (VH) at 3.7 5V, and the adjustable minimum set voltage signal (VL) is changed to 2.25V. The result of the analog signal (VTH) generated by the conversion formula conversion will change from 2.25V to 3.75V, and it will be compared with the triangular wave signal (TRI). The high voltage and low voltage are compared and the output signal is observed. The result is shown in the state 2 (CASE2) waveform of Figure 5A. When the analog signal (VTH) is 2.25V, it is in contact with the triangular wave signal (TRI). The time potential is also higher than the low voltage of the triangular wave signal (TRI) of 1.25V, so there is an output speed at the beginning of state 2 (CASE2).

After that, the motor generated by the output signals of the three states of ORG (VH=3.75V, VL=1.25V), CASE1 (VH=3.75V, VL=0V), CASE2 (VH=3.75V, VL=2.25V) The output speed is converted into a speed curve according to a duty cycle (ie, a PWM signal), and the duty cycle is converted into a speed curve. Referring to FIG. 5B and FIG. 5A, as shown in FIG. 5B, the speed of the first embodiment of the present invention is In the graph, the horizontal axis is the control signal (that is, the PWM signal) and its duty cycle (Duty cycle%), and the vertical axis is the motor output speed ratio (Duty%). Observe the original state (ORG) speed curve during the duty cycle ( Duty cycle) varies from 0% to 100%. According to Figure 5A, the analog signal (VTH) results in the same voltage as the triangular wave signal (TRI), so the motor output speed curve is linear. Change; then, observe the speed of state 1 (CASE1) The curve changes from 0% to 100% in the duty cycle. According to Figure 5A, since the analog signal (VTH) starts from 0V, the analog wave (VTH) changes to 1.25V and the triangle wave When the signal (TRI) is in contact, the output speed will start at this time. Therefore, the analog signal (VTH) has no output speed when it is 0V to 1.25V, as shown in the state 1 (CASE1) speed curve in Figure 5B, during the duty cycle (Duty When the cycle is 33%, the motor starts to have the output of the speed; then observe the change of the speed curve of the state 2 (CASE2) from 0% to 100% in the duty cycle, as described in Figure 5A, when the analog signal When (VTH) is 2.25V, it is in contact with the triangular wave signal (TRI). At this time, the potential is also higher than the low voltage of the triangular wave signal (TRI), which is 1.25V. Therefore, the output of the motor speed is generated from the beginning, as shown in Fig. 5B. 2 (CASE2) speed curve, 40% motor output speed ratio (Duty%) when the duty cycle is 0%; in summary, the first embodiment can be used when the motor speed is reduced to some After the degree, it can be adjusted according to the needs of different motors and different systems. When the motor needs to maintain the minimum heat dissipation When the capacity is available, it can be adjusted to the state 2 (CASE2) setting; if the system does not need to dissipate heat at this time, and the energy saving mode is required, it can be adjusted to the state 1 (CASE1) setting, when the PWM signal is less than 33% (can be adjusted according to system requirements), the motor will not output a signal. For the above two system requirements, the output of the motor at low speed can be adjusted by adjusting the adjustable minimum set voltage signal (VL) (as shown by the dotted line in Figure 5B). However, in order to prevent the motor from rotating to a certain degree and then stop the rotation, it is desirable to fix the motor at a speed that can be controlled by the minimum speed setting to control the minimum heat dissipation of the motor and to achieve energy-saving effects.

Please refer to FIG. 6A. FIG. 6A is a schematic diagram of the waveform of the first implementation exception plus minimum speed setting of the present invention. For convenience of explanation, the adjustment range of CASE1 and CASE2 of FIG. 5B is reduced from 40% DUTY to 20% DUTY, as shown by the dashed line in FIG. 6B. Please refer to FIG. 6A for three states: ORG (VH=3.75V, VL=1.25V), CASE1 (VH=3.75V, VL=0.625V), CASE2 (VH=3.75V, VL=1.75V). The adjustable minimum speed setting voltage signal (ALG) is compared with the analog signal (VTH) generated by the conversion formula and the triangular wave signal (TRI), and the output signal is observed to control the motor output speed. As shown in Figure 6A, Assume that under the original state (ORG), the high voltage of the triangular wave signal (TRI) is fixed at 3.75V, the low voltage is fixed at 1.25V, and the adjustable maximum set voltage signal (VH) is fixed at 3.75V, the adjustable minimum setting. The voltage signal (VL) is set to 1.25V, and the adjustable minimum speed setting voltage signal (ALG) is set to 2V. The analog signal (VTH) generated by the conversion formula conversion will be 1.25V to 3.75V. The change is compared with the high voltage and low voltage of the triangular wave signal (TRI) and the adjustable minimum speed set voltage signal (ALG), and the output signal is observed, and the result is as shown in the original state of FIG. 6A ( ORG) waveform diagram. Please refer to the original state (ORG) waveform diagram of FIG. 6A and according to the original state (ORG) waveform diagram of FIG. 5A, since the result of the analog signal (VTH) is consistent with the high voltage and low voltage of the triangular wave signal (TRI), Between 1.25V and 3.75V, but the adjustable minimum speed setting voltage signal (ALG) 2V, so that the motor can operate at the lowest speed, so when the analog signal (VTH) is less than the adjustable minimum speed set voltage signal (ALG) When the potential is 2V, the voltage signal (ALG) is set according to the adjustable minimum speed to output the speed; when the analog signal (VTH) is greater than the potential of the adjustable minimum speed setting voltage signal (ALG) by 2V, the analog signal (VTH) will be used. When compared with the triangular wave signal (TRI) to output the rotational speed, the result will change linearly. Secondly, it is assumed that under state 1 (CASE1), the high voltage of the triangular wave signal (TRI) is fixed at 3.75V, the low voltage is fixed at 1.25V, and the adjustable maximum set voltage signal (VH) is fixed at 3.75V, which is adjustable. The minimum set voltage signal (VL) is changed to 0.625V, and the additional adjustable minimum speed setting voltage signal (ALG) is changed to 1.75V. The result of the analog signal (VTH) generated after conversion formula conversion will be Between 0.625V and 3.75V, compare it with the high voltage and low voltage of the triangular wave signal (TRI) and the adjustable minimum speed setting voltage signal (ALG), and observe the output signal to control the motor output speed. The result is shown in the state 1 (CASE1) waveform diagram of Figure 6A. Please refer to the state 1 (CASE1) waveform diagram of Figure 6A and the description of the waveform 1 of the state 1 (CASE1) of Figure 5A, since the analog signal (VTH) is 0V starts to change. When the analog signal (VTH) changes to 1.25V, it will be in contact with the triangle wave signal (TRI). At this time, the output speed will start to be there, but in order to avoid the motor from rotating, there is no output speed. Speed setting voltage signal (ALG) 1.75V to control Maintain a minimum speed of the motor, when the analog signals (VTH of) less than Adjustable When the minimum speed setting voltage signal (ALG) potential is 1.75V, the voltage signal (ALG) is set according to the adjustable minimum speed to output the speed; when the analog signal (VTH) is greater than the adjustable minimum speed setting voltage signal (ALG) potential 1.75 After V, the analog signal (VTH) is compared with the triangular wave signal (TRI) to output the rotational speed, and the result will change linearly; secondly, under the state 2 (CASE2), the triangular wave signal (TRI) The high voltage is fixed at 3.75V, the low voltage is fixed at 1.25V, the adjustable maximum set voltage signal (VH) is fixed at 3.75V, the adjustable minimum set voltage signal (VL) is changed to 1.75V, and the adjustable is added. The minimum speed setting voltage signal (ALG) is changed to 2.25V. The result of the analog signal (VTH) generated by the conversion formula conversion will vary from 1.75V to 3.75V, and it will be compared with the triangular wave signal (TRI). Compare with the low voltage and the added adjustable minimum speed setting voltage signal (ALG), and observe the output signal. The result is shown in the state 2 (CASE2) waveform of Figure 6A. Please refer to the state 2 of Figure 6A (CASE2). Waveform diagram and according to the state 2 (CASE2) waveform diagram of Figure 5A When the analog signal (VTH) is 1.75V, it is in contact with the triangular wave signal (TRI). At this time, the potential is also higher than the low voltage of the triangular wave signal (TRI), which is 1.25V, so there is output at the beginning of state 2 (CASE2). Speed, but if the motor is too hot due to a large amount of heat, in order to meet the heat dissipation requirements, the adjustable minimum speed setting voltage signal (ALG) 2.25V is applied to control the motor to maintain the minimum speed and effectively adjust the temperature when the analog signal ( VTH) is less than the adjustable minimum speed setting voltage signal (ALG) potential 2.25V, the voltage signal (ALG) is set according to the adjustable minimum speed to output the speed; when the analog signal (VTH) is greater than the adjustable minimum speed setting voltage signal ( After the potential of ALG) is 2.25V, the analog signal (VTH) is compared with the triangular wave signal (TRI) to output the rotation speed, and the result will change linearly.

After that, the output signals of the three states of ORG (VH=3.75V, VL=1.25V), CASE1 (VH=3.75V, VL=0.625V), CASE2 (VH=3.75V, VL=1.75V) are generated. The motor output speed is converted into a speed curve according to the duty cycle (ie, PWM signal) according to the duty cycle (refer to the PWM signal). Please refer to FIG. 6B and FIG. 6A, as shown in FIG. 6B, which is the first implementation of the creation. The speed curve of the minimum speed setting, the horizontal axis is the control signal (ie, PWM signal), its duty cycle (Duty cycle%), and the vertical axis is the motor output speed ratio (Duty%), observe The rotational speed curve of the original state (ORG) varies from 0% to 100% in the duty cycle. According to FIG. 6A and in conjunction with FIG. 6B, the result of the analog signal (VTH) is higher than the triangular wave signal (TRI). The voltage and low voltage are the same, but the adjustable minimum speed setting voltage signal (ALG) is 2V, so that the motor can operate at the minimum speed, so when the analog signal (VTH) is less than the adjustable minimum speed setting voltage signal (ALG) potential 2V The output speed ratio (Duty%) will be maintained at 30%, that is, the duty cycle ratio (Duty%) will remain at 30% between 0% and 30% of the Duty cycle, when the analog signal (VTH) After the potential of the adjustable minimum speed setting voltage signal (ALG) is 2V (that is, after the duty cycle is 30%), the output speed ratio (Duty%) results in a linear change. Next, observe the change of the speed curve of the state 1 (CASE1) from 0% to 100% in the duty cycle, according to FIG. 6A and in conjunction with FIG. 6B, since the analog signal (VTH) starts from 0.625V. When the analog signal (VTH) changes to 1.25V, it will be in contact with the triangular wave signal (TRI). At this time, the output speed will start, but in order to avoid the motor from rotating, there is no output speed, so set the adjustable minimum speed setting voltage. The signal (ALG) 1.75V controls the motor to maintain the minimum speed. When the analog signal (VTH) is less than the adjustable minimum speed setting voltage signal (ALG) potential 1.75V, the output speed ratio (Duty%) will be maintained at 20%, that is, The duty ratio (Duty%) of the Duty cycle is maintained at 20% between 0% and 35%; when the analog signal (VTH) is greater than the potential of the adjustable minimum speed set voltage signal (ALG) of 1.75V (That is, after the duty cycle is 36%), the output speed ratio (Duty%) results in a linear change. Then observe the change of the speed curve of state 2 (CASE2) from 0% to 100% in the duty cycle, according to FIG. 6A and with FIG. 6B, when the analog signal (VTH) is 1.75V, it is combined with the triangle wave. The signal (TRI) is in contact, and the potential at this time is also higher than the low voltage of the triangular wave signal (TRI), which is 1.25V. Therefore, the output speed is generated at the beginning of the state 2 (CASE2), but the motor generates a large amount of heat and the temperature is too high. In order to meet the heat dissipation requirement, the adjustable minimum speed setting voltage signal (ALG) 2.25V is applied to control the motor to maintain the minimum speed to effectively adjust the temperature. When the analog signal (VTH) is smaller than the adjustable minimum speed setting voltage signal (ALG) At a potential of 2.25V, the output speed ratio (Duty%) will be maintained at 40%, that is, the duty cycle ratio (Duty%) will be between 0% and 25% of the duty cycle. Maintained at 40%; when the analog signal (VTH) is greater than the potential of the adjustable minimum speed set voltage signal (ALG) of 2.25V (that is, after the duty cycle (the duty cycle is 25%), the output speed ratio (Duty%) The result will vary linearly. In summary, the first implementation exception can be used to maintain the motor operating at the minimum speed after the minimum speed setting, and can also be adjusted according to different motors and different system requirements.

Next, please refer to FIG. 7A, which is a waveform diagram of the second embodiment of the present invention. As shown in FIG. 7A, in the second embodiment, the high voltage of the triangular wave signal (TRI) is fixed to 3.75V, the low voltage is fixed to 1.25V, and the adjustable minimum set voltage signal (VL) is fixed at 1.25V to adjust. The adjustable maximum set voltage signal (VH) is compared with the triangular wave signal (TRI) by the analog signal (VTH) generated by the conversion formula and the output signal is observed; therefore, the state is further divided into three states to describe the comparison result: the original state (ORG) represents a state of VH=3.75V, VL=1.25V, state 1 (CASE1) represents a state of VH=2.9V, VL=1.25V, and state 2 (CASE2) represents VH=5V, VL=1.25. The state of V; first, assume that in the state of ORG (VH=3.75V, VL=1.25V), the high voltage of the triangular wave signal (TRI) is fixed at 3.75V, and the low voltage is fixed at 1.25V, which will be adjusted to the highest setting. The voltage signal (VH) is set to 3.75V, and the adjustable minimum set voltage signal (VL) is fixed at 1.25V. The result of the analog signal (VTH) generated by the conversion formula conversion will vary from 1.25V to 3.75V. Compare it with the high voltage and low voltage of the triangular wave signal (TRI) and observe the output signal. The result is shown in Figure 7A. The state (ORG) waveform diagram, because the result of the analog signal (VTH) is consistent with the high voltage and low voltage of the triangular wave signal (TRI), the output speed will change linearly. Secondly, it is assumed that CASE1 (VH=2.9V, In the state of VL=1.25V), the high voltage of the triangular wave signal (TRI) is fixed at 3.75V, the low voltage is fixed at 1.25V, and the adjustable maximum set voltage signal (VH) is set to 2.9V, and the adjustable minimum setting is made. The voltage signal (VL) is fixed at 1.25V. The result of the analog signal (VTH) generated by the conversion formula conversion will vary from 1.25V to 2.9V, and it will be combined with the high voltage and low voltage of the triangular wave signal (TRI). Compare and observe the output signal, and the result is shown in the state 1 (CASE1) waveform diagram of Figure 7A. When the analog signal (VTH) is 1.25V, it is in contact with the triangular wave signal (TRI). At this time, the potential and the triangular wave The low voltage of the signal (TRI) is 1.25V, so the output speed starts from the beginning, but the output speed is lower because the highest change of the analog signal (VTH) is 2.9V lower than the high voltage of the triangular wave signal (TRI) of 3.75V. It will be smaller than the output speed when the analog signal (VTH) is 3.75V in the ORG state; secondly, it is assumed that the high voltage of the triangular wave signal (TRI) is fixed in the state of CASE2 (VH=5V, VL=1.25V). It is 3.75V, the low voltage is fixed at 1.25V, the adjustable maximum set voltage signal (VH) is set to 5V, and the adjustable minimum set voltage signal (VL) is fixed at 1.25V, and the analogy generated by the conversion formula is converted. The result of the signal (VTH) will vary from 1.25V to 5V, compare it with the high voltage and low voltage of the triangular wave signal (TRI) and observe the output signal. The result is the state 2 (CASE2) waveform of Figure 7A. In the figure, when the analog signal (VTH) is 1.25V, it is in contact with the triangular wave signal (TRI). At this time, the potential is the same as the low voltage of 1.25V of the triangular wave signal (TRI), so the output speed starts from the beginning, but because of the analogy The highest change of the signal (VTH) is 5V higher than the high voltage of the triangular wave signal (TRI) of 3.75V. This output rotation speed than in the state of the analog signal ORG (VTH of) a large output speed of 3.75V.

After that, the motor generated by the output signals of the three states of ORG (VH=3.75V, VL=1.25V), CASE1 (VH=2.9V, VL=1.25V), CASE2 (VH=5V, VL=1.25V) The output speed is converted into a speed curve according to the duty cycle (ie, PWM signal), and the duty cycle is converted into a speed curve. Referring to FIG. 7B and FIG. 7A, as shown in FIG. 7B, the speed of the second embodiment of the present invention is In the graph, the horizontal axis is the control signal (ie, PWM signal) and its duty cycle (Duty cycle%), and the vertical axis is the motor output speed ratio (Duty%). Observe the original state (ORG) speed curve during the duty cycle. (Duty cycle) from 0% to 100% change, according to Figure 7A, the analog signal (VTH) results will be consistent with the high voltage and low voltage of the triangular wave signal (TRI), so the motor output speed curve will be linear The change of the speed curve under state 1 (CASE1) is from 0% to 100% in the duty cycle. According to FIG. 7A, when the analog signal (VTH) is 1.25V, The triangular wave signal (TRI) is in contact, and the potential at this time is the same as the low voltage 1.25V of the triangular wave signal (TRI), so there is an output speed at the beginning, but Because the highest change of analog signal (VTH) is 2.9V lower than the high voltage of 3.75V of triangular wave signal (TRI), because The output speed will be smaller than the output speed when the analog signal (VTH) is 3.75V in the ORG state, as shown in the state 1 (CASE1) of Figure 7B. It is only 67 when the duty cycle is 100%. % motor output speed ratio (Duty%); then observe the change of the speed curve under state 2 (CASE2) from 0% to 100% in the duty cycle, according to Figure 7A, when the analog signal (VTH) When it is 1.25V, it is in contact with the triangular wave signal (TRI). At this time, the potential is the same as the low voltage of 1.25V of the triangular wave signal (TRI), so the output speed starts from the beginning, but the highest change due to the analog signal (VTH). The high voltage of the 5V triangular wave signal (TRI) is 3.75V high, so the output speed will be larger than the output speed when the analog signal (VTH) is 3.75V in the ORG state, as shown in the state 2 (CASE2) of Figure 7B. The curve reaches 100% motor output speed ratio (Duty%) when the duty cycle is 67%; in summary, the second embodiment can be used for different system requirements corresponding to the motor heat dissipation capacity setting, such as the system. The required heat dissipation capability can be adjusted to the state 1 (CASE1) setting if it does not need to be large, such as The required heat dissipation capacity needs to be output to the maximum at the early stage, and can be adjusted to the state 2 (CASE2) setting. Therefore, when the temperature of the cooling fan such as VGA or CPU is too high, the adjustable maximum setting can be adjusted in order to effectively adjust the temperature. The voltage signal (VH) adjusts the output of the motor at high speed (as indicated by the dashed line in Figure 7B, which represents the adjustable range), thereby reducing the temperature of the cooling fan. However, in order to quickly reduce the temperature of the cooling fan, it is also possible to control the motor to achieve heat dissipation through the function of the minimum speed setting and to take into account the energy saving effect.

Please refer to FIG. 8A. FIG. 8A is a waveform diagram of the second embodiment of the present invention with the exception of the lowest speed setting. Obviously, the difference between FIG. 8A and FIG. 7A is only that: FIG. 8A is in three states ORG (VH=3.75V, VL=1.25V), CASE1 (VH=2.9V, VL=1.25V), CASE2 (VH). =5V, VL=1.25V) is equipped with an adjustable minimum speed set voltage signal (ALG), which is compared with the analog signal (VTH) generated by the conversion formula and the triangular wave signal (TRI), and observed Its output signal controls the motor output speed. As shown in Fig. 8A, it is assumed that under the original state (ORG), the high voltage of the triangular wave signal (TRI) is fixed at 3.75V, the low voltage is fixed at 1.25V, and the adjustable maximum set voltage signal (VH) is set to 3.75. V, adjustable minimum The constant voltage signal (VL) is fixed at 1.25V, and the adjustable minimum speed setting voltage signal (ALG) is set to 2V. The analog signal (VTH) generated by the conversion formula conversion will be 1.25V to 3.75. The change between V is compared with the high voltage and low voltage of the triangular wave signal (TRI) and the adjustable minimum speed setting voltage signal (ALG), and the output signal is observed, and the result is as shown in the original state of FIG. 8A. (ORG) waveform diagram, please refer to the original state (ORG) waveform diagram of Figure 8A and according to the original state (ORG) waveform diagram of Figure 7A, due to the analog signal (VTH) result and the high voltage of the triangular wave signal (TRI) Consistent with low voltage, it will vary from 1.25V to 3.75V, but after setting the adjustable minimum speed setting voltage signal (ALG) 2V, the motor can operate at the minimum speed to meet the minimum heat dissipation requirements of the motor, so when the analog signal ( VTH) is less than the adjustable minimum speed setting voltage signal (ALG) potential 2V, the voltage signal (ALG) is set according to the adjustable minimum speed to output the speed; when the analog signal (VTH) is greater than the adjustable minimum speed setting voltage signal (ALG) After the potential of 2V, it will be its class Comparing the signal (VTH) with the triangular wave signal (TRI) to output the rotational speed, the result will change linearly. Secondly, under the state of state 1 (CASE1), the high voltage of the triangular wave signal (TRI) is fixed at 3.75V. The low voltage is fixed at 1.25V, the adjustable maximum set voltage signal (VH) is set to 2.9V, the adjustable minimum set voltage signal (VL) is fixed at 1.25V, and the adjustable minimum speed setting voltage signal is added ( ALG) is changed to 1.75V. The result of the analog signal (VTH) generated by the conversion formula conversion will vary from 1.25V to 2.9V, and it will be combined with the high voltage and low voltage of the triangular wave signal (TRI) and The adjustable minimum speed setting voltage signal (ALG) is compared together, and the output signal is observed to control the motor output speed. The result is shown in the waveform 1 of the state 1 (CASE1) of FIG. 8A. Please refer to the state 1 (CASE1) of FIG. 8A. The waveform diagram is in accordance with the state 1 (CASE1) waveform diagram of Figure 7A. When the analog signal (VTH) is 1.25V, it is in contact with the triangular wave signal (TRI). At this time, the potential and the low voltage of the triangular wave signal (TRI) are 1.25. V is consistent, so there is output speed at the beginning, but due to the class The highest change of the signal (VTH) is 2.9V lower than the high voltage of 3.75V of the triangular wave signal (TRI), so the output speed will be smaller than the output speed when the analog signal (VTH) is 3.75V in the ORG state, but the setting is smaller. Adjustable minimum speed setting voltage signal (ALG) 1.75V, so that the motor can operate at the lowest speed to meet the lowest motor The thermal requirement, therefore, when the analog signal (VTH) is less than the 1.75V potential of the adjustable minimum speed setting voltage signal (ALG), the voltage signal (ALG) is set according to the adjustable minimum speed to output the speed; when the analog signal (VTH) After the potential of the adjustable minimum speed setting voltage signal (ALG) is 1.75V, the analog signal (VTH) is compared with the triangular wave signal (TRI) to output the rotation speed, and the result will change linearly; secondly, it is assumed to be in the state. In the state of 2 (CASE2), the high voltage of the triangular wave signal (TRI) is fixed at 3.75V, the low voltage is fixed at 1.25V, and the adjustable maximum set voltage signal (VH) is set to 5V, and the minimum set voltage signal can be adjusted ( VL) is fixed at 1.25V, and the adjustable minimum speed setting voltage signal (ALG) is changed to 2.25V. The analog signal (VTH) generated after conversion formula conversion will be between 1.25V and 5V. Change, compare it with the high voltage and low voltage of the triangle wave signal (TRI) and the adjustable minimum speed setting voltage signal (ALG), and observe the output signal. The result is shown in Figure 2A state 2 (CASE2 ) Waveform, please refer to state 2 (CASE2) of Figure 8A According to the description of the state 2 (CASE2) waveform diagram of Fig. 7A, when the analog signal (VTH) is 1.25V, it is in contact with the triangular wave signal (TRI). At this time, the potential and the low voltage of the triangular wave signal (TRI) are 1.25. V is consistent, so there is output speed at the beginning, but since the highest change of analog signal (VTH) is 5V higher than the high voltage of 3.75V of triangle wave signal (TRI), the output speed will be analogous to the analog signal in ORG state ( When the VTH) is 3.75V, the output speed is large, but after setting the adjustable minimum speed setting voltage signal (ALG) 2.25V, the motor can be operated at the minimum speed to meet the minimum heat dissipation requirement of the motor, so when the analog signal (VTH) is smaller than When the adjustable minimum speed setting voltage signal (ALG) potential is 2.25V, the voltage signal (ALG) is set according to the adjustable minimum speed to output the speed; when the analog signal (VTH) is greater than the adjustable minimum speed setting voltage signal (ALG) After the potential is 2.25V, the analog signal (VTH) is compared with the triangular wave signal (TRI) to output the rotation speed, and the result will change linearly.

After that, the motor generated by the output signals of the three states of ORG (VH=3.75V, VL=1.25V), CASE1 (VH=2.9V, VL=1.25V), CASE2 (VH=5V, VL=1.25V) The output speed is converted into a speed curve according to the duty cycle (ie, PWM signal), and the duty cycle is converted into a speed curve. Referring to FIG. 8B and FIG. 8A, as shown in FIG. 8B, the second is the second creation. The speed curve of the exception plus minimum speed setting is implemented. The horizontal axis is the control signal (ie, PWM signal) and its duty cycle (Duty cycle%), and the vertical axis is the motor output speed ratio (Duty%). Observe the original state (ORG). The speed curve of the duty cycle varies from 0% to 100% in the duty cycle. According to Figure 8A and in conjunction with Figure 8B, the analog signal (VTH) results in high voltage and low voltage with the triangular wave signal (TRI). Consistent, but set the adjustable minimum speed setting voltage signal (ALG) 2V, so that the motor can operate at the lowest speed, so when the analog signal (VTH) is less than the adjustable minimum speed set voltage signal (ALG) potential 2V output speed ratio (Duty%) will remain at 30%, that is, the duty cycle (Duty%) will remain at 30% between 0% and 30%, when the analog signal (VTH) is greater than the adjustable minimum After the potential of the speed setting voltage signal (ALG) is 2V (that is, after the duty cycle is 30%), the output speed ratio (Duty%) results in a linear change. Next, observe the change of the speed curve of the state 1 (CASE1) from 0% to 100% in the duty cycle, according to FIG. 8A and with 8B, when the analog signal (VTH) is 1.25V, the triangle wave The signal (TRI) is in contact. The potential at this time is the same as the low voltage of 1.25V of the triangular wave signal (TRI). Therefore, the output speed starts from the beginning, but the highest change of the analog signal (VTH) is 2.9V compared to the triangular wave signal (TRI). The high voltage of 3.75V is low, so the output speed will be smaller than the output speed when the analog signal (VTH) is 3.75V in the ORG state, but the motor can be set after the adjustable minimum speed setting voltage signal (ALG) is 1.75V. It can be operated at the minimum speed to meet the minimum heat dissipation requirement of the motor. Therefore, when the analog signal (VTH) is less than the adjustable minimum speed set voltage signal (ALG) potential of 1.75V, the output speed ratio (Duty%) will remain at 20%. That is, the Duty cycle will maintain the output speed ratio (Duty%) between 0% and 30.3% at 20%; when the analog signal (VTH) is greater than the adjustable minimum speed set voltage signal (ALG), the potential is 1.75V. After (that is, after the duty cycle (Duty cycle) is 30.3%), the output speed ratio (Duty%) If the will was a linear change. Then observe the change of the speed curve of state 2 (CASE2) from 0% to 100% in the duty cycle, according to FIG. 8A and with FIG. 8B, when the analog signal (VTH) is 1.25V, it is combined with the triangular wave. The signal (TRI) is in contact. The potential at this time is the same as the low voltage of 1.25V of the triangular wave signal (TRI). Therefore, the output speed starts from the beginning, but the highest change of the analog signal (VTH) is 5V compared to the triangular wave signal. The high voltage of (TRI) is 3.75V, so the output speed will be larger than the output speed when the analog signal (VTH) is 3.75V in the ORG state, but after setting the adjustable minimum speed setting voltage signal (ALG) 2.25V, The motor can be operated at the minimum speed to meet the minimum heat dissipation requirement of the motor. Therefore, the output speed ratio (Duty%) is maintained at 40% when the analog signal (VTH) is less than the 2.25V potential of the adjustable minimum speed set voltage signal (ALG). , that is, the Duty cycle between 0% and 26.6%, the output speed ratio (Duty%) will be maintained at 40%; when the analog signal (VTH) is greater than the adjustable minimum speed set voltage signal (ALG) potential After 2.25V (that is, after the duty cycle (26.6%), the output speed ratio (Duty%) results in a linear change. In summary, the second implementation exception can be used to maintain the motor operating at the minimum speed after the minimum speed setting, and can also be adjusted according to different motors and different system requirements.

Next, please refer to FIG. 9A, which is a waveform diagram of the third embodiment of the present invention. As shown in FIG. 9A, in the third embodiment, the high voltage of the triangular wave signal (TRI) is fixed to 3.75V, and the low voltage is fixed to 1.25V, and the adjustable minimum set voltage signal (VL) and the adjustable maximum setting are simultaneously adjusted. The voltage signal (VH) is compared with the triangular wave signal (TRI) by the analog signal (VTH) generated by the conversion formula and observes its output signal; therefore, it is further divided into three states to illustrate the comparison result: the original state (ORG) system Representing a state of VH=3.75V, VL=1.25V, state 1 (CASE1) represents a state of VH=3V, VL=2V, and state 2 (CASE2) represents a state of VH=5V, VL=0V; first, assuming In the state of ORG (VH=3.75V, VL=1.25V), the high voltage of the triangular wave signal (TRI) is fixed at 3.75V, the low voltage is fixed at 1.25V, and the adjustable minimum set voltage signal (VL) is set to 1.25V, and the adjustable maximum set voltage signal (VH) is set to 3.75V. The result of the analog signal (VTH) generated by the conversion formula conversion will vary from 1.25V to 3.75V, and it will be combined with the triangular wave signal (TRI). ) The high voltage and low voltage are compared and the output signal is observed. The result is shown in the original state (ORG) waveform of Figure 9A. Since the result of the analog signal (VTH) is consistent with the high voltage and low voltage of the triangular wave signal (TRI), the output speed will change linearly. Secondly, assuming CASE1 (VH=3V, VL=2V), The triangular wave signal (TRI) has a high voltage fixed at 3.75V and a low voltage fixed at 1.25V. The adjustable maximum set voltage signal (VH) is set. It is 3V, and the adjustable minimum set voltage signal (VL) is set to 2V. The result of the analog signal (VTH) generated by the conversion formula conversion will vary from 2V to 3V, which is higher than the triangular wave signal (TRI). Comparing the voltage and the low voltage and observing the output signal, the result is shown in the state 1 (CASE1) waveform diagram of Fig. 9A. When the analog signal (VTH) is 2V, it is in contact with the triangular wave signal (TRI), so at the beginning There is output speed, and the potential at this time will be higher than the low voltage of 1.25V of the triangular wave signal (TRI), so the output speed will be larger than the output speed when the analog signal (VTH) is 1.25V in the ORG state. The highest change of analog signal (VTH) is 3V lower than the high voltage of 3.75V of the triangular wave signal (TRI), so the output speed will be smaller than the output speed when the analog signal (VTH) is 3.75V in the ORG state; then, Assume that in the state of CASE2 (VH=5V, VL=0V), the high voltage of the triangular wave signal (TRI) is fixed at 3.75V, the low voltage is fixed at 1.25V, and the adjustable maximum set voltage signal (VH) is set to 5V. And the adjustable minimum set voltage signal (VL) is set to 0V, and the class generated after conversion formula conversion The result of the signal (VTH) will vary from 0V to 5V, compare it with the high voltage and low voltage of the triangular wave signal (TRI) and observe the output signal. The result is shown in the state 2 (CASE2) waveform of Figure 9A. Since the analog signal (VTH) starts from 0V, when the analog signal (VTH) is 1.25V, it will be in contact with the triangular wave signal (TRI). At this time, the output speed will start, but due to the analog signal (VTH) The highest change is 5V higher than the high voltage of the triangular wave signal (TRI) of 3.75V, so the output speed will be larger than the output speed when the analog signal (VTH) is 3.75V in the ORG state.

After that, the motor output speed generated by the output signals of ORG (VH=3.75V, VL=1.25V), CASE1 (VH=3V, VL=2V), CASE2 (VH=5V, VL=0V) is based on the output speed of the motor. The control signal (that is, the PWM signal) is converted into a speed curve by a duty cycle. Referring to FIG. 9B and FIG. 9A, as shown in FIG. 9B, it is a rotation speed graph of the third embodiment of the present invention. The horizontal axis is the control signal (that is, the PWM signal) its duty cycle (Duty cycle%), the vertical axis is the motor output speed ratio (Duty%), and the original state (ORG) is observed in the duty cycle (Duty cycle). From 0% to 100% change, according to Figure 9A, the analog signal (VTH) results will be consistent with the high voltage and low voltage of the triangular wave signal (TRI), so the motor output speed will be a linear change; then, observe that the speed curve of state 1 (CASE1) changes from 0% to 100% in the duty cycle, as described in Figure 9A, when the analog signal (VTH) is 2V The triangular wave signal (TRI) is in contact, so there is an output speed at the beginning, and the potential at this time will be higher than the low voltage of the triangular wave signal (TRI) by 1.25V, so the output speed will be higher than the analog signal (VTH) in the ORG state. The output speed is 1.25V, and the highest change of the analog signal (VTH) is 3V lower than the high voltage of 3.75V of the triangular wave signal (TRI), so the output speed will be lower than the analog signal (VTH) in the ORG state. The output speed is 3.75V, as shown in the state 1 (CASE1) speed curve in Figure 9B. When the duty cycle is 0%, there is a 30% motor output speed ratio (Duty%), and when the duty cycle ( When the Duty cycle is 100%, only 70% of the motor output speed ratio (Duty%); then observe the state 2 (CASE2) speed curve in the duty cycle (Duty cycle) from 0% to 100%, according to the diagram As described in 9A, since the analog signal (VTH) starts from 0V, it will be compared with the triangular wave signal when the analog signal (VTH) is 1.25V. TRI) contact, the output speed will start at this time, but since the highest change of the analog signal (VTH) is 5V higher than the high voltage of the triangular wave signal (TRI) is 3.75V, the output speed will be analogous to the analog signal in the ORG state. When the (VTH) is 3.75V, the output speed is large, as shown in the state 2 (CASE2) speed curve of Fig. 9B. When the duty cycle is 25%, the motor starts to have the output of the speed, and during the duty cycle (Duty cycle) When the motor is 67%, the motor output speed ratio (Duty%) is 100%; in summary, the third embodiment simultaneously adjusts the adjustable maximum set voltage signal (VH) and the adjustable minimum set voltage signal (VL). It can be used to adjust the output of the motor at high speed and low speed (as shown by the dotted line in Figure 9B), so as to meet the needs of different motors and adapt to different applications, increasing the flexibility of the motor application. However, in order to prevent the motor from rotating to a certain degree and then stop the rotation and to effectively adjust the temperature, the minimum speed setting function can be used to control the motor to maintain the minimum heat dissipation requirement and to balance the energy saving effect.

Please refer to FIG. 10A, which is a waveform diagram of the third embodiment of the present invention with the exception of the lowest speed setting. Obviously, the difference between FIG. 10A and FIG. 9A is only that: FIG. 10A is in three states ORG (VH=3.75V, VL=1.25V), CASE1 (VH=3V, VL=2V), CASE2 (VH=5V, VL=0V) is equipped with an adjustable minimum speed setting voltage signal (ALG), which is compared with the analog signal (VTH) generated by the conversion formula and the triangular wave signal (TRI). And observe its output signal to control the motor output speed. As shown in FIG. 10A, it is assumed that under the original state (ORG), the high voltage of the triangular wave signal (TRI) is fixed at 3.75V, the low voltage is fixed at 1.25V, and the adjustable minimum set voltage signal (VL) is set to 1.25. V, the adjustable maximum set voltage signal (VH) is set to 3.75V, and the adjustable minimum speed setting voltage signal (ALG) is set to 2V, and the result of the analog signal (VTH) generated by the conversion formula conversion will be Between 1.25V and 3.75V, compare it with the high voltage and low voltage of the triangular wave signal (TRI) and the adjustable minimum speed setting voltage signal (ALG), and observe the output signal. The result is as follows. For the original state (ORG) waveform diagram of FIG. 10A, please refer to the original state (ORG) waveform diagram of FIG. 10A and according to the description of the original state (ORG) waveform diagram of FIG. 9A, due to the analog signal (VTH) result and the triangular wave signal ( The high voltage and low voltage of TRI) are consistent between 1.25V and 3.75V, but the adjustable minimum speed setting voltage signal (ALG) is 2V, so that the motor can operate at the minimum speed, so when the analog signal (VTH) Less than the adjustable minimum speed setting voltage signal (ALG) potential 2V, will The adjustable minimum speed setting voltage signal (ALG) is used to output the speed; when the analog signal (VTH) is greater than the potential of the adjustable minimum speed setting voltage signal (ALG) by 2V, the analog signal (VTH) and the triangular wave signal (TRI) are used. Comparing the output speeds, the result will vary linearly. Secondly, it is assumed that under state 1 (CASE1), the high voltage of the triangular wave signal (TRI) is fixed at 3.75V, the low voltage is fixed at 1.25V, and the adjustable maximum set voltage signal (VH) is set to 3V, which is the lowest adjustable. Set the voltage signal (VL) to 2V, and change the adjustable minimum speed setting voltage signal (ALG) to 2.25V. The analog signal (VTH) generated after conversion formula conversion will be 2V to 3V. The change is compared with the high voltage and low voltage of the triangular wave signal (TRI) and the adjustable minimum speed set voltage signal (ALG), and the output signal is observed, and the result is shown in the state 1 of FIG. 10A ( CASE1) Waveform diagram, please refer to the state 1 (CASE1) waveform diagram of FIG. 10A and according to the state 1 (CASE1) waveform diagram of FIG. 9A, when the analog signal (VTH) is 2V, it is in contact with the triangular wave signal (TRI). Therefore, there is an output speed at the beginning, and the potential at this time will be higher than the triangular wave signal (TRI). The low voltage is 1.25V, so the output speed will be larger than the output speed when the analog signal (VTH) is 1.25V in the ORG state, and the highest change of the analog signal (VTH) is 3V compared to the triangular wave signal (TRI). The high voltage is 3.75V, so the output speed will be smaller than the output speed when the analog signal (VTH) is 3.75V in the ORG state, but the motor can be operated after setting the adjustable minimum speed setting voltage signal (ALG) 2.25V. The minimum speed is in accordance with the minimum heat dissipation requirement of the motor. Therefore, when the analog signal (VTH) is less than the potential of the adjustable minimum speed setting voltage signal (ALG) 2.25V, the voltage signal (ALG) is set according to the adjustable minimum speed to output the speed. When the analog signal (VTH) is greater than the potential of the adjustable minimum speed set voltage signal (ALG) 2.25V, the analog signal (VTH) is compared with the triangular wave signal (TRI) to output the speed, and the result will change linearly. Secondly, under state 2 (CASE2), the high voltage of the triangular wave signal (TR1) is fixed at 3.75V, the low voltage is fixed at 1.25V, and the adjustable maximum set voltage signal (VH) is set to 5V. Adjust the minimum set voltage signal (VL) to 0V And the external adjustable minimum speed setting voltage signal (ALG) is changed to 1.75V, and the result of the analog signal (VTH) generated by the conversion formula conversion will vary from 0V to 5V, and it is combined with the triangular wave signal (TRI). The high voltage is compared with the low voltage and the adjustable minimum speed set voltage signal (ALG), and the output signal is observed. The result is shown in Figure 2A state 2 (CASE2) waveform, see Figure 10A State 2 (CASE2) waveform diagram and according to the state 2 (CASE2) waveform diagram of Figure 9A, since the analog signal (VTH) starts from 0V, it will be compared with the triangular wave signal when the analog signal (VTH) is 1.25V ( TRI) contact, the output speed will start at this time, but since the highest change of the analog signal (VTH) is 5V higher than the high voltage of the triangular wave signal (TRI) is 3.75V, the output speed will be analogous to the analog signal in the ORG state. When the (VTH) is 3.75V, the output speed is large, but the adjustable minimum speed setting voltage signal (ALG) is 1.75V, so that the motor can operate at the minimum speed to meet the minimum heat dissipation requirement of the motor, so when the analog signal (VTH) Less than the adjustable minimum speed setting voltage When the potential of the number (ALG) is 1.75V, the voltage signal (ALG) is set according to the adjustable minimum speed to output the rotation speed; when the analog signal (VTH) is greater than the potential of the adjustable minimum speed setting voltage signal (ALG) of 1.75V, Comparing its analog signal (VTH) with the triangular wave signal (TRI) to output the rotational speed, the result will change linearly.

After that, the motor output speed generated by the output signals of ORG (VH=3.75V, VL=1.25V), CASE1 (VH=3V, VL=2V), CASE2 (VH=5V, VL=0V) is based on the output speed of the motor. The control signal (that is, the PWM signal) is converted into a speed curve by the Duty cycle. Please refer to FIG. 10B and FIG. 10A, as shown in FIG. 10B, which is the third implementation exception of the creation and the minimum speed setting. The speed graph, the horizontal axis is the control signal (ie, PWM signal), its duty cycle (Duty cycle%), the vertical axis is the motor output speed ratio (Duty%), and the speed curve under the original state (ORG) is working. The duty cycle varies from 0% to 100%. According to Figure 10A and in conjunction with Figure 10B, the analog signal (VTH) results will be consistent with the high voltage and low voltage of the triangular wave signal (TRI), but the settings are adjustable. The minimum speed setting voltage signal (ALG) 2V allows the motor to operate at the minimum speed, so the output speed ratio (Duty%) is maintained when the analog signal (VTH) is less than the adjustable minimum speed set voltage signal (ALG) potential 2V. The output speed ratio (Duty%) is maintained at 30% at 30%, that is, the duty cycle is between 0% and 30%. When the analog signal (VTH) is greater than the potential of the adjustable minimum speed set voltage signal (ALG) by 2V (that is, after the duty cycle (30%), the output speed ratio (Duty%) results will change linearly. . Next, observe the change of the speed curve under the state 1 (CASE1) from 0% to 100% in the duty cycle, according to FIG. 10A and with 10B, when the analog signal (VTH) is 2V, the triangle wave The signal (TRI) is in contact, so there is an output speed at the beginning, and the potential at this time will be higher than the low voltage of the triangular wave signal (TRI) by 1.25V, so the output speed will be lower than the analog signal (VTH) in the ORG state. The output speed is 1.25V, and the highest change of the analog signal (VTH) is 3V, which is lower than the high voltage of 3.75V of the triangular wave signal (TRI). Therefore, the output speed will be lower than the analog signal (VTH) in the ORG state. The output speed is 3.75V, but the adjustable minimum speed setting voltage signal (ALG) 2.25V allows the motor to operate at the minimum speed to meet the minimum heat dissipation requirement of the motor, so when the analog signal (VTH) is less than the adjustable minimum When the potential of the speed setting voltage signal (ALG) is 2.25V, the output speed ratio (Duty%) will be maintained at 20%, that is, the duty cycle ratio (Duty%) will be between 0% and 25% of the duty cycle. Maintain at 20%; when the analog signal (VTH) is greater than the adjustable minimum speed setting voltage (ALG) after the potential of 1.3V (i.e., the duty cycle (Duty cycle) of After 25%), the output speed ratio (Duty%) results in a linear change; then observe the state 2 (CASE2) speed curve in the duty cycle (Duty cycle) from 0% to 100% change, according to the diagram 10A and in conjunction with FIG. 10B, since the analog signal (VTH) starts from 0V, when the analog signal (VTH) is 1.25V, it will be in contact with the triangular wave signal (TRI), and the output speed will start at this time, but Since the highest change of the analog signal (VTH) is 5V higher than the high voltage of the triangular wave signal (TRI) of 3.75V, the output speed will be larger than the output speed of the analog signal (VTH) of 3.75V in the ORG state, but the setting is higher. Adjustable minimum speed setting voltage signal (ALG) 1.75V, so that the motor can operate at the minimum speed to meet the minimum heat dissipation requirements of the motor, so when the analog signal (VTH) is less than the adjustable minimum speed set voltage signal (ALG) potential 1.75 The output speed ratio (Duty%) at V will be maintained at 40%, that is, the duty cycle ratio (Duty%) will remain at 40% between 0% and 35% during duty cycle (Duty%); when analog signal (VTH) ) is greater than the adjustable minimum speed setting voltage signal (ALG) potential 1.75V (that is, duty cycle (Duty cy After cle) is 35%, the output speed ratio (Duty%) results in a linear change. In summary, the third implementation exception can be used to maintain the motor operating at the minimum speed after the minimum speed setting, and can also be adjusted according to different motors and different system requirements.

Finally, please refer to FIG. 11 , which is a flow chart of the motor driving method of the present invention. As shown in FIG. 11, the motor driving method includes the following steps: Step 1100: providing a PWM conversion circuit; the PWM conversion circuit has a first input terminal, a second input terminal, a third input terminal, and an output terminal The first input end is connected to a PWM signal, the second input end is connected to an adjustable maximum set voltage signal (VH), and the third input end is connected to an adjustable minimum set voltage signal (VL), and is outputted by the output end. A analog signal (VTH) is output, wherein the analog signal (VTH) can be changed by adjusting the PWM signal, the adjustable maximum set voltage signal (VH) or the adjustable minimum set voltage signal (VL), and then proceeds to step 1101.

Step 1101: An oscillating circuit is provided. The oscillating circuit is configured to generate a triangular wave signal, and the triangular wave signal is adjustable between a high voltage level and a low voltage level, and then proceeds to step 1102.

Step 1102: providing a comparator; the comparator has a first input terminal, a second input terminal, a third input terminal, and an output terminal, wherein the first input terminal is connected to the triangular wave signal generated by the oscillating circuit, and the second The input terminal is connected with the analog signal outputted by the PWM conversion circuit, the third input terminal receives an adjustable minimum speed setting voltage signal, and a driving signal (S_DR) is generated by the output terminal, and finally proceeds to step 1103.

Step 1103: Provide a control unit; the control unit is configured to receive a driving signal generated by the comparator to control a motor.

Although the present invention has been described above with reference to the preferred embodiments thereof, it is not intended to limit the present invention, and anyone skilled in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of patent protection of the creation shall be subject to the definition of the scope of the patent application attached to this specification.

10‧‧‧PWM conversion circuit

12‧‧‧Oscillation circuit

14‧‧‧ Comparator

16‧‧‧Control unit

18‧‧‧Motor

20‧‧‧Inverter

101‧‧‧Control signal

102‧‧‧Adjustable maximum set voltage signal

103‧‧‧ Adjustable minimum set voltage signal

141‧‧‧ Adjustable minimum speed setting voltage signal

R2‧‧‧second resistance

C2‧‧‧second capacitor

1100, 1101, 1102, 1103‧‧ steps

VTH‧‧‧ analog signal

TRI‧‧‧ triangle wave signal

OP1‧‧‧First Operational Amplifier

OP2‧‧‧Second operational amplifier

OP3‧‧‧ Third operational amplifier

TG1‧‧‧first switching element

TG2‧‧‧Second switching element

VA‧‧‧ output node

N‧‧‧ public node

R1‧‧‧first resistance

C1‧‧‧first capacitor

S_DR‧‧‧ drive signal

Figure 1 is a schematic diagram of the output curve of the conventional pulse width modulation control motor drive; Figure 2 is the schematic diagram of the motor drive device of the creation; Figure 3 is the PWM conversion circuit diagram of the creation; Figure 4 is the basis Figure 5A is a waveform diagram of the first embodiment of the creation; Figure 5B is a rotation speed diagram of the first embodiment of the creation; Figure 6A is the first implementation of the creation The waveform diagram of the exception plus the minimum speed setting; FIG. 6B is a graph of the speed of the first implementation exception plus the minimum speed setting of the creation; FIG. 7A is a waveform diagram of the second embodiment of the creation; FIG. 7B is the creation of the present invention The rotation speed graph of the second embodiment; FIG. 8A is a waveform diagram of the second implementation exception plus the minimum rotation speed setting of the creation; FIG. 8B is a rotation speed diagram of the second implementation exception plus the minimum rotation speed setting of the creation; FIG. Is a waveform diagram of the third embodiment of the creation; 9B is a graph showing the rotation speed of the third embodiment of the present invention; FIG. 10A is a waveform diagram of the third embodiment of the creation with the minimum speed setting; FIG. 10B is the third embodiment of the creation with the minimum speed setting. The speed curve diagram; Figure 11 is a flow chart of the motor drive method of the present invention.

10‧‧‧PWM conversion circuit

12‧‧‧Oscillation circuit

14‧‧‧ Comparator

16‧‧‧Control unit

18‧‧‧Motor

101‧‧‧Control signal

102‧‧‧Adjustable maximum set voltage signal

103‧‧‧ Adjustable minimum set voltage signal

141‧‧‧ Adjustable minimum speed setting voltage signal

S_DR‧‧‧ drive signal

VTH‧‧‧ analog signal

TRI‧‧‧ triangle wave signal

Claims (11)

A motor driving device having a minimum speed setting includes: a PWM conversion circuit having a first input terminal, a second input terminal, a third input terminal, and an output terminal, wherein the first input terminal and a control signal Connected, the second input terminal is connected to an adjustable maximum set voltage signal (VH), and the third input terminal is connected to an adjustable minimum set voltage signal (VL), and an output signal is outputted by the output terminal, wherein The analog signal can be changed by adjusting the control signal, the adjustable maximum set voltage signal (VH) or the adjustable minimum set voltage signal (VL); an oscillating circuit for generating a triangular wave signal; and a comparison The first input end, a second input end, a third input end, and an output end, wherein the first input end is connected to the triangular wave signal generated by the oscillating circuit, and the second input end is coupled to the The analog signal outputted by the PWM conversion circuit is connected, the third input terminal receives an adjustable minimum speed setting voltage signal, and a driving signal is outputted by the output terminal. A motor drive device having a minimum rotational speed setting according to claim 1 of the patent application, further comprising a control unit for receiving the drive signal to control a motor. According to the motor drive device of claim 1, wherein the PWM conversion circuit further includes: a first operational amplifier having a positive input terminal electrically connected to the adjustable maximum set voltage signal, a negative input terminal, and an output terminal electrically connected to the negative input terminal; a second operational amplifier having a positive input terminal electrically connected to the adjustable minimum set voltage signal, a negative input terminal, and an output terminal Electrically connected to the negative input terminal; a first switching element having an input end coupled to the first operational signal coupled to the first operational amplifier, coupled to an output of an output node, coupled to the a control terminal of the control signal and a connection end connected to a common node, the first switching component determining whether to turn on the first input signal according to the control signal; a second switching component having an input terminal coupled to the second operational amplifier, coupled to the output terminal of the output node, coupled to the control terminal of the control signal, and coupled Up to one of the common nodes, the second switching component determines whether to turn on the second input signal according to the control signal; an inverter having an input for receiving the control signal and an output connected And the low-pass filter circuit is configured to convert a voltage generated by the output node into the analog signal. The motor drive device having the lowest speed setting according to claim 1 of the patent application, wherein the control signal is a PWM signal. The motor drive device having the lowest speed setting according to claim 1 of the patent application, wherein the triangular wave signal can be adjusted between a high voltage level and a low voltage level. A motor drive device having a minimum rotational speed setting according to claim 2, wherein the motor is a single phase motor. A motor drive device having a minimum rotational speed setting according to claim 2, wherein the motor is a three-phase motor. A motor drive device having a minimum rotational speed setting according to claim 3, wherein the first switching element is a transmission gate. A motor drive device having a minimum rotational speed setting according to claim 3, wherein the second switching element is a transmission gate. The motor drive device having the lowest speed setting according to claim 3, wherein the low pass filter circuit further comprises: a first resistor having a first end coupled to the output node, and a second a second resistor having a first end coupled to the second end of the first resistor and a second end; a first capacitor having a first end coupled to the second resistor and a second end coupled to the ground; a third operational amplifier having a positive input electrically coupled to the second resistor a contact between the first capacitor, a negative input terminal, and an output terminal electrically connected to the negative input terminal for outputting the analog signal; and a second capacitor having a first end coupled to the a junction between the first resistor and the second resistor, and a second terminal coupled to the output of the third operational amplifier. A motor drive device having a minimum rotational speed setting according to claim 9 of the patent application, wherein the low pass filter circuit is a second order low pass filter circuit.