阅读说明：本技术 超声波电机及其驱动电路 (Ultrasonic motor and drive circuit thereof ) 是由 徐浩桐 黄伯超 王三舟 许诺 于 2020-05-28 设计创作，主要内容包括：本发明公开了一种超声波电机及其驱动电路,属于驱动电路技术领域。所述驱动电路包括：电压源、驱动电感,其中：所述驱动电感的一端与所述电压源电连接,所述驱动电感的另一端与所述超声波电机相连接,所述超声波电机属于容性负载与所述驱动电感形成LCR振荡电路谐振升压。本发明通过利用谐振升压的原理使用驱动电感代替变压器和放大器,解决了现有技术中超声波电机的驱动电路体积过大的问题；达到了减小超声波电机的驱动电路的体积的效果。(The invention discloses an ultrasonic motor and a driving circuit thereof, and belongs to the technical field of driving circuits. The drive circuit includes: voltage source, drive inductance, wherein: one end of the driving inductor is electrically connected with the voltage source, the other end of the driving inductor is connected with the ultrasonic motor, and the ultrasonic motor belongs to a capacitive load and forms LCR oscillation circuit resonance boosting with the driving inductor. According to the invention, the driving inductor is used for replacing a transformer and an amplifier by utilizing the principle of resonance boosting, so that the problem of overlarge volume of a driving circuit of the ultrasonic motor in the prior art is solved; the effect of reducing the volume of the drive circuit of the ultrasonic motor is achieved.)

1. A drive circuit of an ultrasonic motor, comprising: voltage source, drive inductance, wherein: one end of the driving inductor is electrically connected with the voltage source, the other end of the driving inductor is connected with the ultrasonic motor, and the ultrasonic motor belongs to a capacitive load and forms LCR oscillation circuit resonance boosting with the driving inductor.

2. The driving circuit according to claim 1, further comprising a controller and an inverter circuit, wherein the voltage source is a dc voltage source, the dc voltage source is connected to an input terminal of the inverter circuit, an output terminal of the inverter circuit is connected to the stator electrode of the ultrasonic motor via the driving inductor, and a pulse width modulation interface of the controller is electrically connected to a control terminal of the inverter circuit.

3. The drive circuit of claim 2, wherein the inverter circuit comprises a first phase half-bridge inverter circuit, a second phase half-bridge inverter circuit, and an inverter drive circuit, wherein:

the direct-current voltage source is respectively connected to the input ends of the first-phase half-bridge inverter circuit and the second-phase half-bridge inverter circuit to output direct-current voltage;

the first phase half-bridge inverter circuit is electrically connected with one end of a first driving inductor to output a first excitation signal, and the other end of the first driving inductor is connected to a first phase piezoelectric ceramic chip of the ultrasonic motor to output a driving signal to the first phase piezoelectric ceramic chip of the ultrasonic motor;

the second phase half-bridge inverter circuit is electrically connected with one end of a second driving inductor to output a second excitation signal, and the other end of the second driving inductor is connected to a second phase piezoelectric ceramic piece of the ultrasonic motor to output a driving signal to the second phase piezoelectric ceramic piece of the ultrasonic motor;

the controller is electrically connected with the first-phase half-bridge inverter circuit and the second-phase half-bridge inverter circuit through an inverter driving circuit respectively, and provides pulse width modulation signals for the first-phase half-bridge inverter circuit and the second-phase half-bridge inverter circuit respectively.

4. The driver circuit of claim 3, wherein the inverting driver circuit comprises a first optocoupler and a second optocoupler, wherein:

a first control end of the controller and a control end cathode of the first optical coupler output a first pulse width modulation signal, and an output end of the first optical coupler is electrically connected with the first-phase half-bridge inverter circuit;

a second control end of the controller and a control end cathode of the second optical coupler output a second pulse width modulation signal, and an output end of the second optical coupler is electrically connected with the first-phase half-bridge inverter circuit;

the first pulse width modulation signal and the second pulse width modulation signal are mutually same-frequency opposite-phase signals and have the same duty ratio.

5. The driver circuit according to claim 3 or 4, wherein the inverter driver circuit comprises a third optocoupler and a fourth optocoupler, wherein:

a third control end of the controller and a control end cathode of the third optical coupler output a third pulse width modulation signal, and an output end of the third optical coupler is electrically connected with the second phase half-bridge inverter circuit;

a fourth control end of the controller and a control end cathode of the fourth optical coupler output a fourth pulse width modulation signal, and an output end of the fourth optical coupler is electrically connected with the second phase half-bridge inverter circuit;

the third pulse width modulation signal and the fourth pulse width modulation signal are same frequency inverted signals and have the same duty ratio.

6. The driving circuit of claim 5, wherein the phase angle of the third pulse width modulated signal differs from the phase angle of the first pulse width modulated signal by 90 °.

7. The driver circuit of claim 4, wherein the first phase half-bridge inverter circuit comprises first and second NPN transistors, a first diode, and a second diode, wherein:

a collector electrode of a first NPN type triode is electrically connected with the direct-current voltage output end and a cathode of the first diode respectively, an emitter electrode of the first NPN type triode is electrically connected with an anode of the first diode, an emitter electrode of the output end of the first optical coupler and the first driving inductor, and a base electrode of the first NPN type triode is electrically connected with a base electrode of the output end of the first optical coupler;

and a collector electrode of the second NPN type triode is electrically connected with an emitting electrode of the first NPN type triode and a cathode of the second diode respectively, the emitting electrode of the second NPN type triode is electrically connected with an anode of the second diode and an emitting electrode of the output end of the second optocoupler and is grounded, and a base electrode of the second NPN type triode is electrically connected with a base electrode of the output end of the second optocoupler.

8. The drive circuit according to claim 7,

the base electrode of the first NPN type is connected with the direct-current voltage output end through a first resistor, and the base electrode of the second NPN type is connected with the direct-current voltage output end through a second resistor; and/or the presence of a gas in the gas,

the direct-current voltage output end is connected with one end of a first capacitor, and the other end of the first capacitor is grounded; the one end of the first capacitor is connected with the emitter of the second NPN type through a second capacitor and is grounded.

9. The driver circuit of claim 5, wherein the second phase half-bridge inverter circuit comprises third and fourth NPN transistors, third and fourth diodes, and wherein:

a collector electrode of a third NPN type triode is electrically connected with the direct-current voltage output end and a cathode of the third diode respectively, an emitter electrode of the third NPN type triode is electrically connected with an anode electrode of the third diode, an emitter electrode of an output end of the third optocoupler and the second driving inductor, and a base electrode of the third NPN type triode is electrically connected with a base electrode of the output end of the third optocoupler;

and a collector electrode of a fourth NPN type triode is electrically connected with an emitter electrode of the third NPN type triode and a cathode electrode of the fourth diode respectively, the emitter electrode of the fourth NPN type triode is electrically connected with an anode electrode of the fourth diode and an emitter electrode of the output end of the fourth optocoupler and is grounded, and a base electrode of the fourth NPN type triode is electrically connected with a base electrode of the output end of the fourth optocoupler.

10. The drive circuit according to claim 8,

the base electrode of the third NPN type is connected with the direct-current voltage output end through a third resistor, and the base electrode of the fourth NPN type is connected with the direct-current voltage output end through a fourth resistor; and/or the presence of a gas in the gas,

the direct-current voltage output end is connected with one end of a third capacitor, and the other end of the third capacitor is grounded; the one end of the third capacitor is connected with the emitter of the fourth NPN type through a fourth capacitor and is grounded.

11. An ultrasonic motor, characterized in that it comprises a drive circuit according to any one of claims 1 to 10.

Technical Field

The invention relates to the technical field of driving circuits, in particular to an ultrasonic motor and a driving circuit thereof.

Background

The ultrasonic motor has a series of advantages of simple and compact structure, easy miniaturization, fast response and braking, power failure self-locking, good control characteristic, high positioning precision, no magnetism, no influence of a magnetic field, low speed, large torque, small noise and the like, and has wide application prospect and use value in the high and new technical fields of aviation, aerospace, medical treatment, robots, precise instruments and meters and the like.

In some application fields, piezoelectric ceramics in a driving ultrasonic motor are required to be driven by high-frequency sinusoidal voltage with large amplitude, a transformer or an amplifier is generally used for providing the high-frequency sinusoidal voltage for driving a traditional driving circuit, but the traditional driving circuit is difficult to meet the requirements of small size and light weight due to the fact that the transformer is difficult to be small in size, the amplifier needs to be matched with a high-voltage power supply and the like, and the driving circuit of the motor is miniaturized to be one of key technologies for development of the ultrasonic motor.

Disclosure of Invention

In order to solve the problem that the volume of a driving circuit of an ultrasonic motor is too large in the prior art, the embodiment of the invention provides an ultrasonic motor and a driving circuit thereof. The technical scheme is as follows:

in a first aspect, a driving circuit of an ultrasonic motor is provided, including: voltage source, drive inductance, wherein: one end of the driving inductor is electrically connected with the voltage source, the other end of the driving inductor is connected with the ultrasonic motor, and the ultrasonic motor belongs to a capacitive load and forms LCR oscillation circuit resonance boosting with the driving inductor.

Optionally, the driving circuit further includes a controller and an inverter circuit, the voltage source is a dc voltage source, the dc voltage source is connected to an input end of the inverter circuit, an output end of the inverter circuit is connected to the stator electrode of the ultrasonic motor through the driving inductor, and a pulse width modulation interface of the controller is electrically connected to a control end of the inverter circuit.

Optionally, the inverter circuit includes a first-phase half-bridge inverter circuit, a second-phase half-bridge inverter circuit, and an inverter driving circuit, wherein: the direct-current voltage source is respectively connected to the input ends of the first-phase half-bridge inverter circuit and the second-phase half-bridge inverter circuit to output direct-current voltage; the first phase half-bridge inverter circuit is electrically connected with one end of a first driving inductor to output a first excitation signal, and the other end of the first driving inductor is connected to a first phase piezoelectric ceramic chip of the ultrasonic motor to output a driving signal to the first phase piezoelectric ceramic chip of the ultrasonic motor; the second phase half-bridge inverter circuit is electrically connected with one end of a second driving inductor to output a second excitation signal, and the other end of the second driving inductor is connected to a second phase piezoelectric ceramic piece of the ultrasonic motor to output a driving signal to the second phase piezoelectric ceramic piece of the ultrasonic motor; the controller is electrically connected with the first-phase half-bridge inverter circuit and the second-phase half-bridge inverter circuit through an inverter driving circuit respectively, and provides pulse width modulation signals for the first-phase half-bridge inverter circuit and the second-phase half-bridge inverter circuit respectively.

Optionally, the inverter driving circuit includes a first optical coupler and a second optical coupler, wherein: a first control end of the controller and a control end cathode of the first optical coupler output a first pulse width modulation signal, and an output end of the first optical coupler is electrically connected with the first-phase half-bridge inverter circuit; a second control end of the controller and a control end cathode of the second optical coupler output a second pulse width modulation signal, and an output end of the second optical coupler is electrically connected with the first-phase half-bridge inverter circuit; the first pulse width modulation signal and the second pulse width modulation signal are mutually same-frequency opposite-phase signals and have the same duty ratio.

Optionally, the inverter driving circuit includes a third optocoupler and a fourth optocoupler, wherein: a third control end of the controller and a control end cathode of the third optical coupler output a third pulse width modulation signal, and an output end of the third optical coupler is electrically connected with the second phase half-bridge inverter circuit; a fourth control end of the controller and a control end cathode of the fourth optical coupler output a fourth pulse width modulation signal, and an output end of the fourth optical coupler is electrically connected with the second phase half-bridge inverter circuit; the third pulse width modulation signal and the fourth pulse width modulation signal are same frequency inverted signals and have the same duty ratio.

Optionally, the phase angle of the third pwm signal is different from the phase angle of the first pwm signal by 90 °.

Optionally, the first phase half-bridge inverter circuit includes a first NPN type triode and a second NPN type triode, and a first diode and a second diode, wherein: a collector electrode of a first NPN type triode is electrically connected with the direct-current voltage output end and a cathode of the first diode respectively, an emitter electrode of the first NPN type triode is electrically connected with an anode of the first diode, an emitter electrode of the output end of the first optical coupler and the first driving inductor, and a base electrode of the first NPN type triode is electrically connected with a base electrode of the output end of the first optical coupler; and a collector electrode of the second NPN type triode is electrically connected with an emitting electrode of the first NPN type triode and a cathode of the second diode respectively, the emitting electrode of the second NPN type triode is electrically connected with an anode of the second diode and an emitting electrode of the output end of the second optocoupler and is grounded, and a base electrode of the second NPN type triode is electrically connected with a base electrode of the output end of the second optocoupler.

Optionally, the base of the first NPN is connected to the dc voltage output terminal through a first resistor, and the base of the second NPN is connected to the dc voltage output terminal through a second resistor; and/or the direct-current voltage output end is connected with one end of a first capacitor, and the other end of the first capacitor is grounded; the one end of the first capacitor is connected with the emitter of the second NPN type through a second capacitor and is grounded.

Optionally, the second phase half-bridge inverter circuit includes a third NPN type triode and a fourth NPN type triode, and a third diode and a fourth diode, where: a collector electrode of a third NPN type triode is electrically connected with the direct-current voltage output end and a cathode of the third diode respectively, an emitter electrode of the third NPN type triode is electrically connected with an anode electrode of the third diode, an emitter electrode of an output end of the third optocoupler and the second driving inductor, and a base electrode of the third NPN type triode is electrically connected with a base electrode of the output end of the third optocoupler; and a collector electrode of a fourth NPN type triode is electrically connected with an emitter electrode of the third NPN type triode and a cathode electrode of the fourth diode respectively, the emitter electrode of the fourth NPN type triode is electrically connected with an anode electrode of the fourth diode and an emitter electrode of the output end of the fourth optocoupler and is grounded, and a base electrode of the fourth NPN type triode is electrically connected with a base electrode of the output end of the fourth optocoupler.

Optionally, the base of the third NPN is connected to the dc voltage output terminal through a third resistor, and the base of the fourth NPN is connected to the dc voltage output terminal through a fourth resistor; and/or the direct-current voltage output end is connected with one end of a third capacitor, and the other end of the third capacitor is grounded; the one end of the third capacitor is connected with the emitter of the fourth NPN type through a fourth capacitor and is grounded.

In a second aspect, an ultrasonic motor is provided, wherein the ultrasonic motor includes the driving circuit according to the first aspect and any one of the optional embodiments of the first aspect.

The technical scheme provided by the embodiment of the invention has the following beneficial effects:

by providing an ultrasonic motor and a driving circuit thereof, which includes: voltage source, drive inductance, wherein: one end of the driving inductor is electrically connected with the voltage source, the other end of the driving inductor is connected with the ultrasonic motor, and the ultrasonic motor belongs to a capacitive load and forms LCR oscillation circuit resonance boosting with the driving inductor. According to the invention, the driving inductor is used for replacing a transformer and an amplifier by utilizing the principle of resonance boosting, so that the problem of overlarge volume of a driving circuit of the ultrasonic motor in the prior art is solved; the effect of reducing the volume of the drive circuit of the ultrasonic motor is achieved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic diagram of a drive circuit for an ultrasonic motor according to one embodiment of the present invention;

fig. 2 is a circuit diagram of the connection of the first phase half-bridge inverter circuit 20 and the first driving inductor according to an embodiment of the present invention;

fig. 3 is a circuit diagram of the connection of a second phase half-bridge inverter circuit 30 to a second drive inductor according to one embodiment of the present invention;

fig. 4 is a circuit diagram of an inverter driving circuit 50 according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

For the drive circuit problem of solving among the prior art motor on the large side of volume, this application provides a drive circuit of ultrasonic motor, and it includes voltage source, drive inductance, wherein: one end of the driving inductor is electrically connected with the voltage source, the other end of the driving inductor is connected with the ultrasonic motor, and the ultrasonic motor belongs to a capacitive load and forms LCR oscillation circuit resonance boosting with the driving inductor. In this application, utilize the principle that the resonance boosts to use drive inductance to replace transformer and amplifier, when realizing the drive of ultrasonic motor, reduced ultrasonic motor's drive circuit's volume, further reduced ultrasonic motor's volume.

In one example, the voltage source used in the driving circuit is an ac voltage source, and each phase output of the ac voltage source is connected to one phase of the ultrasonic motor through a driving inductor. Furthermore, the ultrasonic motor can be an alternating current voltage source with adjustable frequency, and the rotating speed of the ultrasonic motor can be adjusted by modulating the frequency.

In another example, the driving circuit further includes a controller and an inverter circuit, the voltage source is a dc voltage source, the dc voltage source is connected to an input end of the inverter circuit, an output end of the inverter circuit is connected to the stator electrode of the ultrasonic motor through the driving inductor, and a pulse width modulation interface of the controller is electrically connected to a control end of the inverter circuit. The controller is used for finishing the work of frequency modulation and phase modulation of the pulse width modulation signal. In the description of the driving circuit of the ultrasonic motor in the embodiment, the present application exemplifies two-phase driving of the ultrasonic motor, that is, the driving circuit provides a two-phase driving signal (for example, a column traveling wave type ultrasonic motor). In practical implementation, the driving circuit provided by the application can realize multi-phase driving.

Referring to fig. 1, a schematic diagram of a driving circuit of an ultrasonic motor according to an embodiment of the present invention is shown. As shown in fig. 1, the drive circuit of the ultrasonic motor includes: direct current voltage source 10, inverter circuit, controller 60, inverter circuit includes first looks half-bridge inverter circuit 20, second looks half-bridge inverter circuit 30, inverter drive circuit 50, wherein:

the direct-current voltage source 10 is respectively connected to the input ends of the first-phase half-bridge inverter circuit 20 and the second-phase half-bridge inverter circuit 30 to output a direct-current voltage Ud;

the first-phase half-bridge inverter circuit 20 is electrically connected with one end of a first driving inductor L1 to output a first excitation signal, and the other end of the first driving inductor L1 is connected to a first-phase piezoelectric ceramic plate 40 of the ultrasonic motor to output a driving signal to the first-phase piezoelectric ceramic plate 40 of the ultrasonic motor;

the second-phase half-bridge inverter circuit 30 is electrically connected with one end of a second driving inductor L2 to output a second excitation signal, and the other end of the second driving inductor L2 is connected to a second-phase piezoelectric ceramic plate of the ultrasonic motor to output a driving signal to the second-phase piezoelectric ceramic plate of the ultrasonic motor;

the controller 60 is electrically connected to the first phase half-bridge inverter circuit 20 and the second phase half-bridge inverter circuit 30 through the inverter driving circuit 50, and provides pulse width modulation signals to the first phase half-bridge inverter circuit 20 and the second phase half-bridge inverter circuit 30, respectively. The controller 60 is a device that generates a pulse width modulation signal, and may be any one of an ARM and a DSP, which is not specifically limited in this embodiment.

In one example, the inverter driving circuit 50 may directly adopt an inverter circuit driving dedicated chip, and the controller 60 is electrically connected to the first phase half-bridge inverter circuit 20 and the second phase half-bridge inverter circuit 30 through the inverter circuit driving dedicated chip.

In another example, referring to fig. 4 and fig. 2, the inverter driving circuit 50 includes a first optical coupler U1 and a second optical coupler U2, wherein: a first control terminal (not shown) of the controller 60 and a control terminal cathode of the first optocoupler U1 output a first pulse width modulation signal, a control terminal anode of the first optocoupler U1 is connected to a system supply voltage through a resistor, and an output terminal of the first optocoupler U1 is electrically connected to the first phase half-bridge inverter circuit 20. Specifically, in one example, the first phase half-bridge inverter circuit 20 includes first and second NPN transistors VT1 and VT2, a first diode D1, and a second diode D2, wherein: a collector of the first NPN type triode VT1 is electrically connected to the output terminal of the dc voltage Ud and the cathode of the first diode D1, an emitter of the first NPN type triode VT1 is electrically connected to the anode of the first diode D1, the emitter of the output terminal of the first optocoupler U1, and the first driving inductor L1, and a base of the first NPN type triode VT1 is electrically connected to the base electrode of the output terminal of the first optocoupler U1.

Optionally, referring to fig. 4 and fig. 2, a second control terminal of the controller 60 and a control terminal cathode of the second optical coupler U2 output a second pulse width modulation signal, a control terminal anode of the second optical coupler U2 is connected to a system supply voltage through a resistor, and an output terminal of the second optical coupler U2 is electrically connected to the first-phase half-bridge inverter circuit 20. . Specifically, in an example, a collector of the second NPN transistor VT2 is electrically connected to an emitter of the first NPN transistor VT1 and a cathode of the second diode D2, respectively, an emitter of the second NPN transistor VT2 is electrically connected to an anode of the second diode D2 and an emitter of the output terminal of the second optocoupler U2 and is grounded, and a base of the second NPN transistor VT2 is electrically connected to a base electrode of the output terminal of the second optocoupler U2. The first pulse width modulation signal and the second pulse width modulation signal are mutually same-frequency opposite-phase signals and have the same duty ratio, and the duty ratio is slightly smaller than 50%.

Optionally, the inverter driving circuit 50 includes a third optical coupler U3 and a fourth optical coupler U4, where: a third control end of the controller 60 and a control end cathode of the third optical coupler U3 output a third pulse width modulation signal, and an output end of the third optical coupler U3 is electrically connected with the second phase half bridge inverter circuit 30; a fourth pulse width modulation signal is output by a fourth control end of the controller 60 and a control end cathode of a fourth optical coupler U4, and an output end of the fourth optical coupler U4 is electrically connected with the second phase half-bridge inverter circuit 30; the third pulse width modulation signal and the fourth pulse width modulation signal are same frequency inverted signals and have the same duty ratio, and the duty ratio is slightly smaller than 50%. Wherein the phase angle of the third pulse width modulation signal differs by 90 ° from the phase angle of the first pulse width modulation signal.

Optionally, the base of the first NPN is connected to the output terminal of the dc voltage Ud through a first resistor R3, and the base of the second NPN is connected to the output terminal of the dc voltage Ud through a second resistor R4; and/or the output end of the direct-current voltage Ud is connected with one end of a first capacitor C1, and the other end of the first capacitor C1 is grounded; one end of the first capacitor C1 is connected to the emitter of the second NPN via the second capacitor C2 and grounded.

Optionally, referring to fig. 3, the second-phase half-bridge inverter circuit 30 includes a third NPN transistor and a fourth NPN transistor, and a third diode D3 and a fourth diode D3, where:

a collector of the third NPN triode VT3 is electrically connected to the output terminal of the dc voltage Ud and the cathode of the third diode D3, an emitter of the third NPN triode VT3 is electrically connected to the anode of the third diode D3, an emitter of the output terminal of the third optocoupler U3, and the second driving inductor L2, and a base of the third NPN triode VT3 is electrically connected to the base electrode of the output terminal of the third optocoupler U3; in one example, the anode of the control terminal of the third optocoupler U3 is connected to the system supply voltage through a resistor.

A collector of the fourth NPN triode VT4 is electrically connected to an emitter of the third NPN triode VT3 and a cathode of the fourth diode D3, respectively, an emitter of the fourth NPN triode VT4 is electrically connected to an anode of the fourth diode D3 and an emitter of the output end of the fourth optocoupler U4, and is grounded, and a base of the fourth NPN triode VT4 is electrically connected to a base electrode of the output end of the fourth optocoupler U4; in one example, the anode of the control terminal of the fourth optocoupler U4 is connected to the system supply voltage through a resistor.

Optionally, a base of the third NPN is connected to the output end of the dc voltage Ud through a third resistor R7, and a base of the fourth NPN is connected to the output end of the dc voltage Ud through a fourth resistor R8; and/or the output end of the direct-current voltage Ud is connected with one end of a third capacitor C3, and the other end of the third capacitor C3 is grounded; one end of the third capacitor C3 is connected to the fourth NPN emitter through the fourth capacitor C4 and grounded.

The ultrasonic motor has three speed regulation modes of frequency regulation, phase regulation and voltage regulation. The driving signal output by the first driving inductor to the ultrasonic motor is a sine signal, the driving signal output by the second driving inductor to the ultrasonic motor is also a sine signal, the frequency of the sine signal output by the first driving inductor is the same as that of the first pulse modulation signal and the second pulse modulation signal, and the frequency of the sine signal output by the second driving inductor is the same as that of the third pulse modulation signal and the fourth pulse modulation signal, so that frequency modulation control is realized. By controlling the phase difference between the first pulse modulation signal (i.e., the second pulse modulation signal) and the third pulse modulation signal (i.e., the fourth pulse modulation signal), the phase difference between the driving voltage output by the first driving inductor and the driving voltage output by the second driving inductor can be controlled, and phase modulation control is realized. Because the ultrasonic motor belongs to capacitive load, the motor and the driving inductor form an LCR oscillating circuit (an inverter circuit and a controller are mainly used for exciting the LCR oscillating circuit formed by the driving inductor and the stator of the ultrasonic motor), and the amplitude of the driving voltage output by the first driving inductor L1 and the amplitude of the driving voltage output by the second driving inductor L2 at the working frequency can be controlled by selecting the first driving inductor L1 and the second driving inductor L2, so that the driving requirements are met.

In addition, frequency modulation and phase modulation are completed in the controller, and the driving circuit only has two links of inversion and boosting, so that the modulation steps of the ultrasonic motor driving circuit are optimized for illustration; the inverter, the frequency modulation, the phase shift and the boosting are respectively separated in the traditional driving circuit, and the modulation is complex. In practical implementation, the boost link can be realized by using the driving inductor, other links such as inversion, frequency modulation and phase shift adopt the existing circuit, and the application does not need to be repeated one by one.

In this application, two-phase driving of the ultrasonic motor is exemplified, that is, the driving circuit provides two-phase driving signals for description, and in practical implementation, the driving circuit may also provide multi-phase driving signals. By way of example, the inverter circuit comprises a third phase half-bridge inverter circuit, wherein: the direct current voltage source is connected with the input end of the third phase half-bridge inverter circuit to output direct current voltage; the third phase half-bridge inverter circuit is electrically connected with one end of a third driving inductor to output a third excitation signal, and the other end of the third driving inductor is connected to a third phase piezoelectric ceramic piece of the ultrasonic motor to output a driving signal to the third phase piezoelectric ceramic piece of the ultrasonic motor; the controller is electrically connected with the third phase half-bridge inverter circuit through the inverter driving circuit and provides pulse width modulation signals for the third phase half-bridge inverter circuit. Wherein, other half-bridge inverter circuit of this application can be referred to third half-bridge inverter circuit's circuit connection relation, also can refer to other half-bridge inverter circuit of application with inverter circuit in the connection relation of other components and parts, this application is no longer repeated one by one to this.

The terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying a number of the indicated technical features. Thus, a defined feature of "first", "second", may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program instructing relevant hardware, where the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.