CN114900068A

CN114900068A - Driving device and method for ultrasonic motor

Info

Publication number: CN114900068A
Application number: CN202210442841.2A
Authority: CN
Inventors: 张凌云
Original assignee: Hangzhou Youwang Electronics Co ltd
Current assignee: Hangzhou Youwang Electronics Co ltd
Priority date: 2022-04-25
Filing date: 2022-04-25
Publication date: 2022-08-12

Abstract

The application discloses drive arrangement and drive method of ultrasonic motor, drive arrangement includes: the controller is used for providing control voltage corresponding to the driving frequency according to a preset voltage signal corresponding to the target rotating speed in the working mode of the motor; and the processor is connected with the controller and generates a corresponding driving signal according to the control voltage so as to drive the motor based on the driving signal, the target rotating speed is in a low rotating speed interval, and the corresponding driving frequency changes in a sine wave shape along with time. The driving signal driving motor corresponding to the driving frequency which is in sine wave fluctuation along with time variation is provided under the low rotating speed working mode, so that the rotor of the motor is started and stopped to change slowly in the moment, and noise generated by the rotor of the motor is further suppressed.

Description

Driving device and method for ultrasonic motor

Technical Field

The present invention relates to the field of motor driving technologies, and in particular, to a driving apparatus and method for an ultrasonic motor.

Background

The ultrasonic motor utilizes the inverse piezoelectric effect or the electrostrictive effect to enable a stator of the motor to generate micro mechanical vibration in an ultrasonic frequency band, and the vibration is converted into rotary or linear motion through resonance amplification and frictional coupling. Compared with the traditional motor, the ultrasonic motor has the following characteristics: the device has the advantages of low speed, large torque output, good start-stop controllability, direct drive, accurate positioning, low noise, no electromagnetic interference and the like.

At present, when the ultrasonic motor works in a low-rotating-speed environment, the driving frequency of the ultrasonic motor can deviate from a resonance point, so that the power of the ultrasonic motor is reduced, and the torque is reduced. The currently adopted PWM mode speed regulation can enable the ultrasonic motor to be continuously and instantly started and instantly stopped, and can cause the amplitude variation amplitude of the rotor of the ultrasonic motor to be overlarge at the moment of starting and stopping so as to generate larger noise.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide a driving apparatus and method for an ultrasonic motor, so as to solve the technical problem of noise in the speed regulation and low rotation speed driving of the motor, thereby further improving the stability of the ultrasonic motor.

According to an aspect of the present invention, there is provided a driving apparatus of an ultrasonic motor, including: the controller is used for providing control voltage corresponding to the driving frequency according to a preset voltage signal corresponding to the target rotating speed in the working mode of the motor;

a processor connected with the controller and generating a corresponding driving signal according to the control voltage so as to drive the motor based on the driving signal,

when the target rotating speed is in a low rotating speed interval, the driving frequency changes in a sine wave shape along with time.

Optionally, when the target rotation speed is in a high rotation speed interval, the corresponding driving frequency is a fixed value.

Optionally, the controller is further configured to provide a control voltage in a starting mode of the motor, and the processor generates a corresponding driving signal based on the control voltage, so as to soft start the motor, and operates at a target rotation speed after the soft start.

Optionally, the starting frequency is gradually decreased to a lower limit value of the driving frequency corresponding to the target rotation speed with time.

Optionally, the method further comprises:

and the speed regulator provides the preset voltage signal based on the target rotating speed and provides the preset voltage signal to the controller.

Optionally, the controller comprises:

the control unit is used for storing preset starting time and starting frequency and judging that the motor is in the starting mode or the working mode based on an enabling signal and the preset starting time;

the first operation unit is connected with the control unit, receives the starting frequency in the starting mode, acquires an upper limit value and a lower limit value of the driving frequency according to the preset voltage signal in the working mode, and generates the corresponding driving frequency; and

and the second operation unit is connected with the first operation unit and provides the corresponding control voltage based on the driving frequency and the starting frequency, wherein the control voltage is positively correlated with a frequency value.

Optionally, when the target rotation speed is in a low rotation speed interval, the upper limit value and the lower limit value of the driving frequency are not equal, and the control voltage provided by the corresponding second operation unit is an alternating-current voltage with a direct-current component.

Optionally, when the target rotation speed is in a high rotation speed interval, the upper limit value and the lower limit value of the driving frequency are equal, and the control voltage provided by the corresponding second operation unit is a direct current voltage.

Optionally, the processor comprises:

the signal generating unit is connected with the controller and converts the control voltage to obtain a basic frequency signal;

the frequency division unit is connected with the signal generation unit and is used for carrying out frequency division processing on the basic frequency signal to output four paths of frequency division signals; and

and the driving unit is connected with the frequency dividing unit and converts the four paths of frequency dividing signals to generate two paths of driving signals.

Optionally, a fundamental frequency of the fundamental frequency signal corresponds to 4 times of the driving frequency or the starting frequency, and a frequency of the frequency division signal is one quarter of the fundamental frequency.

Optionally, the driving signal is two sine wave signals with a phase difference therebetween.

Optionally, the motor is in the starting mode within the preset starting time, and enters the working mode after the preset starting time.

According to another aspect of the present invention, there is provided a driving method of an ultrasonic motor, including:

providing a control voltage corresponding to a driving frequency according to a preset voltage signal corresponding to a preset target rotating speed in a working mode of the motor; and

and generating a corresponding driving signal according to the control voltage, and then driving the motor based on the driving signal, wherein when the target rotating speed is in a low rotating speed interval, the driving frequency changes in a sine wave shape along with time.

Optionally, the method further comprises:

providing a control voltage in a start-up mode of the motor; and

and generating a corresponding driving signal based on the control voltage, further performing soft start on the motor, and working at a target rotating speed after the soft start.

Optionally, the step of providing the control voltage in a start-up mode of the motor comprises:

providing a starting frequency based on the enabling signal and a preset starting time; and

and providing a corresponding control voltage based on the starting frequency, wherein the control voltage is positively correlated with the frequency value.

Optionally, the step of providing a corresponding control voltage according to the target rotation speed in the operating mode of the motor includes:

providing a corresponding preset voltage signal based on the target rotating speed;

acquiring corresponding driving frequency according to the preset voltage signal; and

and providing a corresponding control voltage based on the driving frequency, wherein the control voltage is positively correlated with the frequency value.

Optionally, when the target rotation speed is in a low rotation speed interval, obtaining that an upper limit value and a lower limit value of the driving frequency are not equal based on the target rotation speed, and the correspondingly provided control voltage is an alternating-current voltage with a direct-current component.

Optionally, the step of generating a corresponding driving signal according to the control voltage includes:

converting based on the control voltage to obtain a basic frequency signal;

performing frequency division processing on the basic frequency signal to output four paths of frequency division signals; and

and converting the four paths of frequency division signals to generate two paths of driving signals.

Optionally, the method further comprises:

and judging that the motor is in the starting module or the working mode based on an enabling signal and set time, wherein the motor is in the starting mode when an effective edge of the enabling signal arrives, and the working mode is entered after the starting mode lasts for the set time.

According to the driving device and the driving method of the ultrasonic motor, the controller and the processor provide corresponding driving signals based on the target rotating speed to drive the motor, so that the speed regulation control of the motor is realized. And this application provides the drive signal that the drive frequency that is sinusoidal wave form fluctuation corresponds with the time variation under low rotational speed mode and drives the motor to make the rotor of motor start-stop change slowly in the twinkling of an eye, and then restrain the produced noise of rotor of motor.

Further, the electrode driving device provides a driving signal corresponding to the starting frequency which is gradually reduced along with the change of time for the motor to soft start the motor in the starting mode of the motor, so that the motor reaches a resonance point after the change of parameters when being started, and the normal starting of the motor is realized.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

fig. 1 shows a schematic structural diagram of a motor system provided according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram illustrating a driving apparatus provided according to an embodiment of the present invention;

fig. 3 is a schematic diagram showing a relationship between a rotational speed and a driving frequency in the driving apparatus provided according to the embodiment of the present invention;

fig. 4 is a schematic diagram illustrating an operation waveform of the driving apparatus according to the embodiment of the present invention;

fig. 5 is a schematic diagram showing still another operation waveform of the driving apparatus provided in accordance with the embodiment of the present invention;

FIG. 6 is a timing diagram of a processor in the driving apparatus according to the embodiment of the invention;

fig. 7 is a flow chart illustrating a driving method according to an embodiment of the present invention.

Detailed Description

Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by the same or similar reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale.

The driving device and method for the ultrasonic motor can solve the technical problems of noise and the like existing in speed regulation, starting and low-speed rotation of the ultrasonic motor. The following description will be made by taking a driving device and a driving method of a traveling wave type ultrasonic motor as an example. The driving signal of the traveling-wave type ultrasonic motor is two paths of alternating current signals, and the frequency, the amplitude, the phase difference and the waveform of the two paths of alternating current signals have direct influence on the performance parameters of the traveling-wave type ultrasonic motor.

Fig. 1 shows a schematic structural diagram of a motor system provided according to an embodiment of the present invention.

As shown in fig. 1, the motor system includes a motor driving device 100 and a motor 200. The motor drive apparatus 100 includes a controller 110 and a processor 120. The controller 110 is configured to provide a corresponding control voltage according to a preset target rotation speed in an operation mode of the motor 200. The processor 120 is connected to the controller 110, generates a corresponding driving signal according to the control voltage, and drives the motor 200 based on the driving signal, so that the motor 200 operates at a target rotation speed. When the target rotation speed is in the low rotation speed range, the motor 200 is considered to be operated in the low rotation speed operation mode, and the driving frequency of the corresponding driving signal fluctuates with time. So as to avoid the noise caused by the overlarge amplitude variation range of the rotor start-stop moment of the motor due to the continuous instant start and instant stop of the motor 200 in the low-rotation-speed working mode. Further, when the target rotating speed is lower than the first threshold value, the corresponding driving frequency changes in a sine wave shape along with time.

Further, when the target rotation speed is in the high rotation speed interval, the corresponding driving frequency is a fixed value. It should be noted that the target rotation speed in the high rotation speed section is higher than or equal to the first threshold, and the target rotation speed in the low rotation speed section is lower than the first threshold.

In other embodiments, the controller 110 is further configured to provide a control voltage in a start mode of the motor 200, and the processor 120 generates a corresponding driving signal based on the control voltage, and then soft-starts the motor 200 based on the driving signal, and operates at the target rotation speed after the soft start. Further, the start frequency is gradually decreased to the lower limit value of the drive frequency corresponding to the target rotation speed with time.

Fig. 2 is a schematic structural diagram of a driving device provided in accordance with an embodiment of the present invention. Fig. 3 is a schematic diagram showing a relationship between a rotation speed and a driving frequency in the driving device provided in the embodiment of the present invention. Fig. 4 is a schematic diagram illustrating an operation waveform of the driving apparatus according to the embodiment of the present invention. Fig. 5 is a schematic diagram illustrating still another operation waveform of the driving apparatus according to the embodiment of the present invention. Fig. 6 is a timing diagram illustrating a processor in the driving apparatus according to the embodiment of the present invention.

As shown in fig. 2, the motor drive apparatus 100 includes, for example, a controller 110, a processor 120, and a speed governor 130.

The governor 130 provides a corresponding preset voltage signal based on the target rotational speed v and provides the preset voltage signal to the controller 110. One of the preset voltage signal values corresponds to a target rotational speed v.

The controller 110 in the motor drive device 100 includes a first arithmetic unit 111, a second arithmetic unit 112, and a control unit 113. The control unit 113 is configured to store a preset start time and a start frequency, and determine that the motor 200 is in the start mode or the working mode based on the enable signal STV and the preset start time. Further, it is determined that the motor 200 is on or off based on the enable signal STV. Wherein, when the enable signal STV is valid, the motor 200 is turned on, and when the enable signal STV is invalid, the motor 200 is stopped. The set activation time is, for example, 25 ms. Wherein the enabling signal STV is provided, for example, by an external system module. The first operation unit 111 is connected to the control unit 113, and receives the start frequency output by the control unit 113 when the motor 200 is in the start mode, that is, the first operation unit 111 jumps to the active level state for the preset start time after the enable signal STV jumps. When the motor 200 is in the operating mode, that is, after a preset start time elapses, the first arithmetic unit 111 acquires the upper limit value and the lower limit value of the corresponding driving frequency from the preset voltage signal corresponding to the target rotation speed v received from the speed governor 130. When the motor 200 is turned off, even if the enable signal STV is in the inactive level state, the governor 130 does not provide the preset voltage signal to the first arithmetic unit 111 and thus the first arithmetic unit 111 does not provide the driving frequency and the control unit 113 does not provide the starting frequency. The second operation unit 112 is connected to the first operation unit 111, and provides a corresponding control voltage Vctrl based on the driving frequency acquired in the operating mode or the starting frequency acquired in the starting mode, wherein the control voltage Vctrl is positively correlated with the frequency value.

In other embodiments, the enable signal STV is provided directly by the governor 130, for example.

Further, as shown in fig. 3, when the target rotation speed v is in the low rotation speed section, the motor 200 operates in the low rotation speed operation mode based on the target rotation speed, and the driving frequency thereof fluctuates with time. Further, the first arithmetic unit 111 obtains the driving frequency upper limit value F1 and the driving frequency lower limit value F2 based on the target rotation speed v, and the corresponding second arithmetic unit 112 is an alternating current voltage having a direct current component based on the control voltage Vctrl provided by the driving frequency upper limit value F1 and the driving frequency lower limit value F2. When the target rotation speed v is in the high rotation speed interval, the motor 200 operates in the high rotation speed operating mode based on the target rotation speed v, the driving frequency is a fixed value, that is, the obtained upper limit value and the obtained lower limit value of the driving frequency are equal. Further, the first arithmetic unit 111 obtains a constant driving frequency value F3 based on the target rotation speed v, and the corresponding second arithmetic unit 112 is a dc voltage based on the control voltage Vctrl provided by the constant driving frequency value F3. Wherein the driving frequency is related to the motor 200 parameters. In the high-rotation-speed working mode, frequency conversion processing is not needed, and the driving frequency is not changed at the same rotation speed. In the low rotation speed operation mode, the motor 200 needs to maintain a certain torque, and if the lower limit of the driving frequency is too high, the average frequency value is increased, the rotation speed is reduced, so that the torque is insufficient, and further frequency conversion processing is needed.

Further, referring to fig. 4, the operation principle of the controller 110 is shown when the motor 200 is started and operated in the high rotation speed operation mode. When the effective edge of the enable signal received by the control unit 113 of the controller 110 arrives, the motor 200 is in the start mode and continues for the set time t11, and during the set time t11, the first arithmetic unit 111 of the controller 110 provides a preset start frequency (including a frequency corresponding to the frequency F11 curve in the set time t 11), and the start frequency gradually decreases with the increase of time. Specifically, the preset starting frequency includes a frequency value between a set frequency and a driving frequency corresponding to the target rotation speed v. So that the motor 200 can reach a resonance point after parameter change through soft start when starting, the peak power of the motor 200 at the resonance point is increased, the maximum static friction force can be overcome, and the inter-electrode capacitance parameter of the motor 200 is restored to the original inter-electrode capacitance parameter, thereby starting normally. At time t12 after the set time t11, the motor 200 is in the high rotation speed operation mode, and the first arithmetic unit 111 of the controller 110 provides a constant driving frequency (which means the frequency value of the frequency F11 curve in the time t 12) based on the target rotation speed v. Correspondingly, the second operation unit 112 of the controller 110 provides the corresponding control voltage Vctrl1 based on the frequency F11 in the set time t11 and the time t12, respectively. Then, the processor 120 generates a fundamental frequency signal with a fundamental frequency F12 based on the control voltage Vctrl1, and obtains two corresponding driving signals OUT through internal processing.

Further, referring to fig. 5, the operation of the controller 110 is illustrated when the motor 200 is started and operated in the low speed operation mode. When the effective edge of the enable signal received by the control unit 113 of the controller 110 arrives, the motor 200 is in the start mode and continues for the set time t21, and during the set time t21, the first arithmetic unit 111 of the controller 110 provides a preset start frequency (including a frequency corresponding to the frequency F21 curve in the set time t 21), and the start frequency gradually decreases with the increase of time. Specifically, the preset starting frequency includes a lower limit value of the driving frequency corresponding to the set frequency to the target rotation speed v. So that the motor 200 can reach a resonance point after parameter change through soft start when starting, the peak power of the motor 200 at the resonance point is increased, the maximum static friction force can be overcome, and the inter-electrode capacitance parameter of the motor 200 is restored to the original inter-electrode capacitance parameter, thereby starting normally. At time t22 after the set time t21, the motor 200 is in the low rotation speed operation mode, and the first arithmetic unit 111 of the controller 110 provides the upper limit value F1 and the lower limit value F2 of the driving frequency (refer to the maximum value and the minimum value of the frequency F21 curve in the time t 22) based on the target rotation speed v. Correspondingly, the second operation unit 112 of the controller 110 provides the corresponding control voltage Vctrl2 based on the frequency F21 in the set time t21 and the time t22, respectively. Then, the processor 120 generates a fundamental frequency signal with a fundamental frequency F22 based on the control voltage Vctrl2, and obtains two corresponding driving signals OUT through internal processing.

In addition, when the operation mode of the motor 200 is switched from the high-rotation-speed operation mode to the low-rotation-speed operation mode, or is switched from the low-rotation-speed operation mode to the high-rotation-speed operation mode, the target rotation speed v may be directly set by the governor 130, and the controller 110 and the processor 120 control and generate the corresponding driving signal OUT to implement the switching. Or after the motor 200 is turned off, the corresponding working mode is entered after the motor 200 is soft started.

The processor 120 in the motor drive apparatus 100 includes a signal generation unit 121, a frequency division unit 122, and a drive unit 123. The signal generating unit 121 is connected to the second operation unit 112 of the controller 110 and converts the base frequency signal Vb1 based on the control voltage Vctrl. The frequency dividing unit 122 is connected to the signal generating unit 121 and frequency-divides the base frequency signal Vb1 to output a four-way frequency-divided signal Vb 2. The driving unit 123 is connected to the frequency dividing unit 122 and generates two driving signals OUT according to the four frequency dividing signals Vb 2. Further, the fundamental frequency of the fundamental frequency signal Vb1 corresponds to 4 times of the driving frequency or the starting frequency, and specifically, the duty ratio of the fundamental frequency signal Vb1 is, for example, 50%. The frequency of the four-way frequency-divided signal Vb2 is one fourth of the basic frequency, and specifically, the four-way frequency-divided signal Vb2 is, for example, a signal whose phase difference is 90 ° and whose duty ratio is 25%. Further, the driving signal OUT is two sine wave signals having a phase difference therebetween to drive the motor 200 such that a greater torque is generated. In a preferred embodiment, the phase difference between the two sine wave signals in the driving signal OUT is 90 °.

The signal generating unit 121 is, for example, an independent signal generating circuit, which can reduce the resource occupation of the controller 110. The controller 110 is, for example, a single chip microcomputer. Further, the peripheral capacitance resistors of the signal generating unit 121 all use low temperature drift capacitance resistors, for example.

The present application provides a driving apparatus 100, in which the start frequency of the driving signal OUT provided in the start mode is gradually decreased with time. The driving frequency of the driving signal OUT provided in the high rotation speed operation mode is fixed. The driving frequency of the driving signal OUT supplied in the low rotation speed operation mode fluctuates with time. Referring to fig. 6, the operation of the processor 120 will be described in detail by taking an example in which the control voltage Vctrl provided based on the high target rotation speed v generates the corresponding driving signal OUT through the processor 120. In the high rotation speed operation mode, the signal generation unit 121 obtains a fundamental frequency signal Vb1 (the fundamental frequency is a fixed value) based on the control voltage Vctrl provided by the controller 110. The fundamental frequency signal Vb1 is further divided by four by the frequency dividing unit 122 to obtain 4 paths of frequency-divided signals, the frequency-divided signal Vb2-a, the frequency-divided signal Vb2-b, the frequency-divided signal Vb2-c and the frequency-divided signal Vb2-d are, for example, signals which are 90 ° out of phase and 25% in duty ratio and one fourth of the fundamental frequency. The 4-channel frequency-divided signal Vb2 is further converted into 2-channel drive signal OUT having a sinusoidal waveform with a phase difference of, for example, 90 ° by the drive unit 123. Specifically, the frequency-divided signal Vb2-a, the frequency-divided signal Vb2-b, the frequency-divided signal Vb2-c and the frequency-divided signal Vb2-d respectively control the four power tubes in the driving unit 123 to be turned on and off to drive the two push-pull transformers in the driving unit 123. Each push-pull transformer has two groups of windings, for example, a frequency-divided signal Vb2-a and a frequency-divided signal Vb2-b drive the two groups of windings in a first push-pull transformer, a frequency-divided signal Vb2-c and a frequency-divided signal Vb2-d drive the two groups of windings in a second push-pull transformer, the first push-pull transformer outputs a first path of sine wave signals, the second push-pull transformer outputs a second path of sine wave signals, and the phase difference of the two paths of sine wave signals is the same as that of the frequency-divided signal Vb2-a and the frequency-divided signal Vb 2-c. The four paths of frequency division signals are converted into two paths of sine wave signals in the mode.

As shown in fig. 7, the driving method includes:

step S310: and providing a control voltage corresponding to the driving frequency according to a preset voltage signal corresponding to the target rotating speed in the working mode of the motor. Further, the steps include: providing a corresponding preset voltage signal based on the target rotating speed; acquiring corresponding driving frequency according to a preset voltage signal; and providing a corresponding control voltage based on the driving frequency, wherein the control voltage is positively correlated with the frequency value. Further, when the target rotating speed is in the low rotating speed interval, the upper limit value and the lower limit value of the driving frequency are obtained based on the target rotating speed, and the correspondingly provided control voltage is an alternating-current voltage with a direct-current component. Further, when the target rotating speed is in the high rotating speed interval, a fixed value of the driving frequency is obtained based on the target rotating speed, and the correspondingly provided control voltage is direct-current voltage.

Step S320: and generating a corresponding driving signal according to the control voltage, and further driving the motor based on the driving signal. The method comprises the following steps: converting based on the control voltage to obtain a basic frequency signal; frequency-dividing the basic frequency signal to output four paths of frequency-divided signals; and converting the four paths of frequency division signals to generate two paths of driving signals. Further, the fundamental frequency of the fundamental frequency signal corresponds to 4 times of the driving frequency or the starting frequency, and the frequency of the frequency-divided signal is one fourth of the fundamental frequency. Furthermore, the driving signals are two paths of sine wave signals with phase difference.

When the target rotating speed is in the low rotating speed interval, the corresponding driving frequency changes in a sine wave shape along with time. When the target rotating speed is in the high rotating speed interval, the corresponding driving frequency is a fixed value.

In other embodiments, further comprising: providing a control voltage in a start-up mode of the motor; and generating a corresponding driving signal based on the control voltage, further soft-starting the motor at a corresponding starting frequency based on the driving signal, and working at a target rotating speed after the soft-starting. Wherein the step of providing the control voltage in a start-up mode of the motor comprises: providing a starting frequency based on the enabling signal and a preset starting time; and providing a corresponding control voltage based on the starting frequency, wherein the control voltage is positively correlated with the frequency value. Further, still include: and judging that the motor is in a starting module or a working mode based on the enabling signal and the set time, wherein the motor is in the starting mode when the effective edge of the enabling signal arrives, and the starting mode enters the working mode after the set time lasts.

According to the driving device and the driving method of the ultrasonic motor, the controller and the processor provide corresponding driving signals based on the target rotating speed to drive the motor, and the speed regulation control of the motor is achieved. And this application provides the drive signal that the drive frequency that is sinusoidal wave form fluctuation corresponds with the time variation under low rotational speed mode and drives the motor to make the rotor of motor start-stop change slowly in the twinkling of an eye, and then restrain the produced noise of rotor of motor. Further, the electrode driving device provides a driving signal corresponding to the starting frequency which is gradually reduced along with the change of time for the motor to soft start the motor in the starting mode of the motor, so that the motor reaches a resonance point after the change of parameters when being started, and the normal starting of the motor is realized.

While embodiments in accordance with the invention have been described above, these embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments described. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A driving apparatus of an ultrasonic motor, comprising:

the controller is used for providing control voltage corresponding to the driving frequency according to a preset voltage signal corresponding to the target rotating speed in the working mode of the motor;

2. The drive device according to claim 1, wherein the corresponding drive frequency is a fixed value when the target rotation speed is in a high rotation speed interval.

3. The drive device of claim 1, wherein the controller is further configured to provide a control voltage in a start mode of the motor, and the processor generates a corresponding drive signal based on the control voltage to soft start the motor and operate at a target speed after the soft start.

4. The drive device according to claim 3, wherein the start-up frequency is gradually decreased to a lower limit value of the drive frequency corresponding to the target rotation speed with time.

5. The drive device according to claim 3, further comprising:

6. The drive device of claim 5, wherein the controller comprises:

7. The driving apparatus according to claim 6, wherein when the target rotation speed is in a low rotation speed range, an upper limit value and a lower limit value of the driving frequency are not equal, and the control voltage provided by the corresponding second operation unit is an alternating-current voltage having a direct-current component.

8. The drive device according to claim 6, wherein when the target rotation speed is in a high rotation speed section, an upper limit value and a lower limit value of the drive frequency are equal, and the control voltage supplied by the corresponding second arithmetic unit is a direct-current voltage.

9. The drive apparatus of claim 3, wherein the processor comprises:

10. The driving device according to claim 9, wherein a fundamental frequency of the fundamental frequency signal corresponds to 4 times the driving frequency or the start-up frequency, and a frequency of the frequency-divided signal is one-quarter of the fundamental frequency.

11. The driving device according to claim 9, wherein the driving signal is two sine wave signals having a phase difference therebetween.

12. The drive of claim 6, wherein the motor is in the start mode for the preset start time, and the operation mode is entered after the preset start time.

13. A driving method of an ultrasonic motor, comprising:

providing a control voltage corresponding to a driving frequency according to a preset voltage signal corresponding to a target rotating speed in a working mode of the motor; and

and generating a corresponding driving signal according to the control voltage, and further driving the motor based on the driving signal, wherein when the target rotating speed is in a low rotating speed interval, the driving frequency changes in a sine wave shape along with time.

14. The driving method according to claim 13, wherein the corresponding driving frequency is a fixed value when the target rotation speed is in a high rotation speed section.

15. The driving method according to claim 13, further comprising:

providing a control voltage in a start-up mode of the motor; and

16. The driving method according to claim 15, wherein the starting frequency is gradually decreased to a lower limit value of the driving frequency corresponding to the target rotation speed with time.

17. The driving method of claim 15, wherein the step of supplying the control voltage in the start mode of the motor comprises:

18. The driving method according to claim 13, wherein the step of providing the corresponding control voltage according to the target rotation speed in the operation mode of the motor includes:

19. The driving method according to claim 18, wherein when the target rotation speed is in a low rotation speed range, an upper limit value and a lower limit value of the driving frequency are obtained based on the target rotation speed and are not equal to each other, and the correspondingly provided control voltage is an alternating-current voltage having a direct-current component.

20. The driving method according to claim 20, wherein when the target rotation speed is in a high rotation speed section, an upper limit value and a lower limit value of the driving frequency are equal, and the control voltage supplied by the corresponding second arithmetic unit is a direct-current voltage.

21. The driving method according to claim 15, wherein the step of generating the corresponding driving signal according to the control voltage includes:

converting based on the control voltage to obtain a basic frequency signal;

22. The driving method according to claim 21, wherein a fundamental frequency of the fundamental frequency signal corresponds to 4 times the driving frequency or the start-up frequency, and a frequency of the frequency-divided signal is one quarter of the fundamental frequency.

23. The driving method according to claim 21, wherein the driving signal is two sine wave signals that are out of phase with each other.

24. The driving method according to claim 17, further comprising:

and judging that the motor is in the starting mode or the working mode based on an enabling signal and set time, wherein the motor is in the starting mode when an effective edge of the enabling signal arrives, and the working mode is entered after the starting mode lasts for the set time.