KR20200114685A - Method of driving ultrasonic tranducer and ultrasonic vibration device using thereof - Google Patents

Abstract

The present invention relates to an ultrasonic vibrator driving method and an ultrasonic vibrator driving device using the same and, more specifically, to a technique which can easily find and utilize a natural resonance frequency showing a maximum amplitude, and can be applied to various fields. To this end, the present invention provides the ultrasonic vibrator driving method, which changes a driving frequency of an ultrasonic vibrator and measures current consumption according to the change so that the driving frequency when the consumption current reaches the maximum can be an optimum driving frequency of the ultrasonic vibrator.

Description

TECHNICAL FIELD The method of driving ultrasonic transducer and ultrasonic vibration device using the same

The present invention relates to a method of driving an ultrasonic vibrator and a device for driving an ultrasonic vibrator using the same, and to a technique for easily finding and utilizing a unique resonance frequency showing a maximum amplitude, and applying the same to various fields.

Ultrasonic vibration is used to prevent scale, which degrades efficiency in heat exchangers such as boilers, prevents aquatic organisms from sticking to the surface of a ship, thereby preventing fuel efficiency from dropping, or preventing the occurrence of green algae in reservoirs or lakes. Or, it is applied in a wide variety of fields such as increasing extrusion efficiency by lowering extrusion resistance in extrusion of plastics.

When the driving method of the ultrasonic vibrator is broadly divided, there are a fixed frequency method that is driven with a fixed frequency regardless of the fluctuation of the load, and a vibration tracking method that controls the driving frequency according to the resonance condition of the vibrator according to the application of the load. The fixed frequency method is useful for washing machines or humidifiers with relatively little or no load change, but is not suitable for maintaining optimum efficiency for applications in which the vibrator is mechanically connected to the object to directly supply the vibrator's energy.

The ultrasonic vibrator has a natural resonant frequency that shows the maximum amplitude, and the resonance frequency varies according to the load applied to the vibrator. Therefore, in order to maintain the optimal operating conditions of the equipment using ultrasonic vibration, it is necessary to find the resonance frequency that gives the maximum amplitude and drive the vibrator with that frequency. Until now, methods for checking the maximum amplitude frequency by installing a separate ultrasonic detector have been used (KR 10-2000-0030494 A1, WO 2012/085630 A1, etc.). To do this, it is necessary to have an ultrasonic detector along with an ultrasonic generator and the device is complicated.

Since the selection of the resonance frequency changes due to various loads of the vibrator, temperature change, aging change, influence of the surroundings, etc., there is a problem that the driving frequency of the ultrasonic vibrator does not fall within an appropriate range. Factors affecting the resonance frequency can be viewed as the impedance of the ultrasonic vibrator. The impedance of these ultrasonic oscillators is complexly changed according to the frequency, and the phase difference between the driving voltage and the current consumption is also very complex, so the method of tracking the resonance frequency in the relationship between these driving voltages and current values and phases. (Ultrasonics 54(2014) 187-194, Resonance tracking and vibration stabilization for high power ultrasonic transducers, Ultrasonics 39(2001) 257-261, High power resonance tracking amplifier using admittance locking, etc.) ).

KR 10-2000-0030494 A1 WO 2012/085630 A1

Y.Kuang etc, Ultrasonics 54(2014) 187-194, Resonance tracking and vibration stabilization for high power ultrasonic transducers B.Mortimert etc, Ultrasonics 39(2001) 257-261, High power resonance tracking amplifier using admittance locking

The present inventor proposes a method for easily finding the resonance frequency of an ultrasonic vibrator without a complicated circuit configuration or algorithm, and intends to increase the utilization of the ultrasonic vibrator by utilizing it in various fields.

The present invention for this purpose is a method of changing the driving frequency of the ultrasonic vibrator and measuring the current consumption accordingly in the driving method of the ultrasonic vibrator, and setting the driving frequency when the consumption current becomes the maximum as the optimum driving frequency of the ultrasonic vibrator. .

This is explained step by step, i) driving the ultrasonic vibrator while changing the driving frequency;, ii) measuring the current consumption in the step i); And iii) setting the driving frequency of step ii) as the optimum driving frequency of the ultrasonic vibrator when the maximum current consumption in step ii) is measured.

In this case, it is preferable that the step of changing the driving frequency of step i) is performed periodically. In addition, when there are many changes in the surrounding environment, a step of changing the driving frequency may be separately set.

This can be used in terms of devices. That is, in the ultrasonic vibrator driving device that vibrates according to the setting of the driving frequency, the driving device measures the current consumed while changing the driving frequency to find the driving frequency at the time when the current consumption becomes maximum, and resets the driving frequency. It is possible to provide an ultrasonic vibrator driving device. The environment in which the driving device of the present invention can be installed is very diverse, and it is used to prevent scale, which reduces efficiency in heat exchangers such as boilers, and prevents aquatic organisms from sticking to the surface of a ship, thereby reducing fuel efficiency. It can be applied to a wide variety of fields, such as preventing, preventing the occurrence of green algae in reservoirs or lakes, or increasing extrusion efficiency by lowering extrusion resistance in extrusion of plastics.

It is possible to easily find the resonance frequency of an ultrasonic vibrator without a complicated circuit configuration or algorithm, and it can be used in various fields.

1 is a block diagram of a device for a driving test of a magnetostrictive vibrator device.
2 is a view showing the configuration of a sound pressure meter manufactured to measure the driving ability of the ultrasonic vibrator of the present invention.
3 is a diagram showing the configuration of an apparatus for measuring a sound pressure and driving an ultrasonic vibrator.
4 is a result showing current consumption and sound pressure depending on the driving frequency of the magnetostrictive vibrator.
5 is a configuration diagram of a device for a driving test of a piezoelectric vibrator.
6 is a result showing current consumption and sound pressure according to the driving frequency of the piezoelectric vibrator.

The present invention relates to a method of finding the resonance frequency of an ultrasonic vibrator without a complicated circuit configuration or algorithm, and to an application thereof.

Ultrasonic vibrators generally used include magnetostrictive vibrators using magnetostriction and piezoelectric vibrators using piezoelectric phenomena.

Magnetostriction refers to a phenomenon in which a ferromagnetic material becomes elastically deformed when it is magnetized, and is also referred to as a magnetic distortion phenomenon. It is caused by an internal impact in the magnetic body due to the anisotropic energy required to magnetize the magnetic body in a certain direction along the crystal axis. Conversely, when an external mechanical impact is applied to a magnetic material, the magnetization state (magnetization rate) of the magnetic material is changed. A material with prominent magnetostriction is used as a magnetostrictive material, and a magnetostrictive vibrator is made using it. On the other hand, when some kind of crystal is placed in an electric field, distortion occurs, or when distortion is applied, piezoelectricity is generated. It is a piezoelectric vibrator that uses this phenomenon. Piezoelectric materials that convert electrical energy and mechanical energy using crystal polarization include single crystal crystal, lithium decarbonate, lithium niobate, and ceramic zircon titanate and barium titanate.

The present inventor measures the load current and ultrasonic sound pressure (acoustic output) consumed when driving these ultrasonic vibrators by varying the frequency of the magnetostrictive vibrators and piezoelectric vibrators. It was confirmed that the current consumption value (I _load ) of the power source was measured with an average ammeter with a time constant of 2 ms) as well. In other words, it has been found that the maximum amplitude is obtained when driving at the frequency that maximizes the current consumption value, so that the ultrasonic device can be operated under the optimum condition simply by finding the optimum frequency without installing a separate ultrasonic detector.

In many fields where ultrasonic vibrators are used, the problem of finding the optimum driving frequency has been an important problem. Accordingly, many patents suggest a method for finding it, or a method optimized according to the specific field in which the ultrasonic vibrator is used. It could be implemented through algorithms and circuits that find it at high cost. However, a relatively simple and inexpensive method is required to further increase the utilization of the ultrasonic vibrator.

The resonance frequency of the ultrasonic vibrator varies depending on the temperature and stress of the vibrator, and also depends on the surrounding environment, that is, load conditions (depth of water, water temperature, flow rate, etc.). It is necessary to confirm the optimal driving state according to these different conditions. That is, if you scan the driving frequency periodically or only when these surrounding conditions vary greatly, check the resonance frequency of the ultrasonic vibrator representing the maximum current consumption value, and repeat the process of driving at that frequency, you will always be able to meet the optimal driving conditions. I can.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein. In order to clearly describe the present invention, unnecessary parts are omitted.

The present inventor has examined whether the technical idea of the present inventor can be applied to both a magnetostrictive vibrator and a piezoelectric vibrator.

1 is a configuration diagram of a device for a driving test of a magnetostrictive vibrator device, FIG. 2 is a diagram showing the configuration of a sound pressure meter manufactured to measure the driving capability of an ultrasonic vibrator of the present invention, and FIG. This is a diagram showing the configuration of a device for measuring sound pressure.

For the ultrasonic sound pressure, an acoustic output detector (Fig.) was used to connect an acoustic tube to the microphone PU0410LR5H-QB, which has excellent ultrasonic characteristics from Knowles. The ultrasonic sound pressure propagated into the water due to the vibration of the ultrasonic vibrator was measured by inserting the sound wave tube of the sound pressure gauge in the water. Attach the magnetostrictive vibrator of the sound treatment device ASP-01 (Neo UMC) to the test device of the sound treatment facility according to the [Inspection Operation Regulations for Water Treatment, etc.] of the Korea Energy Management Corporation, and an acrylic cylinder (diameter 20 cm long) on the top 60 cm) was fixed. The cylinder was filled with water and the ultrasonic sound pressure (acoustic output) transmitted to the water was measured.

4 shows the results. Since the frequency at which the power consumption is maximum and the frequency at which sound pressure is maximum are equal to 19.2 kHz, the maximum amplitude can be secured by finding and driving the frequency at which the current consumption is maximum. Looking at the drive device of FIG. 1, the load current of the power source can be measured simply. In the case of the papers cited above as prior art, the process of finding an appropriate driving frequency through a very complicated process is shown, but in the case of the present invention, it is possible to find it very simply. That is, by observing the current consumption value while changing the frequency, the optimum efficiency can be obtained by finding the resonance frequency at which the maximum current value is obtained, and operating at that frequency.

Next, it was examined whether the technical idea of the present invention is applied to the piezoelectric vibrator. 5 is a configuration diagram of a device for a driving test of a piezoelectric vibrator device. A piezoelectric vibrator (ULC 23540 F) for washing machine of Ulso Hitech Co., Ltd. was driven by a 1:10 transformer using a full bridge drive, while current consumption and ultrasonic sound pressure were measured by changing the frequency. For efficient propagation of ultrasonic vibration, the surface of the vibrator coated with grease was fixed upward, a 1 L beaker was placed on it, and about 700 mL of water was filled, and a sound pressure meter was inserted and the sound pressure was measured.

6 is a result showing current consumption and sound pressure according to the driving frequency of the piezoelectric vibrator. In the case of a piezoelectric vibrator, the frequency at which the power consumption is maximum and the frequency at which sound pressure is maximum are 39.9 kHz, and the maximum amplitude can be secured by finding the frequency at which the current consumption is maximum and driving. However, even at a frequency of 13.3 kHz, which is 1/3 of the maximum current frequency, a small peak is seen because of the 3rd harmonics (39.9 kHz) component contained in the 13.3 kHz square wave.

Based on the above results, the technical core of the present invention can be said as follows. That is, in the method of driving the ultrasonic vibrator, the driving frequency of the ultrasonic vibrator is changed, and the resulting current consumption is measured, and the driving frequency when the consumption current becomes the maximum is the optimal driving frequency of the ultrasonic vibrator. As can be seen in the device configuration diagram for the drive test, all you have to do is check the point of the maximum value while observing the change in the load current of the power source while changing the drive frequency.

This is explained step by step, i) driving the ultrasonic vibrator while changing the driving frequency;, ii) measuring the current consumption in the step i); And iii) setting the driving frequency of step ii) as the optimum driving frequency of the ultrasonic vibrator when the maximum consumption current of step ii) is measured. It may be called a driving method of an ultrasonic vibrator, comprising: have.

Since the optimum driving frequency of the vibrator may vary depending on various environments, it is possible to reset the driving frequency by periodically checking this. When it is used on a ship or used for a device for removing green algae in a lake, it is important to change the driving frequency to the maximum efficiency because the external environment changes. In addition, if a change in the surrounding environment is observable, the driving frequency can be separately changed and reset to the driving frequency of the maximum current consumption period.

The detailed description of the present invention is disclosed in order to solve the technical problem of the present invention, and various modifications and equivalent embodiments that are apparent to those of ordinary skill in the art are carried out within the scope of the appended claims. Understand that you can.

Claims (4)

A method of driving an ultrasonic vibrator, wherein the driving frequency of the ultrasonic vibrator is changed, and the resulting current consumption is measured, and the driving frequency when the current consumption is maximized is the optimum driving frequency of the ultrasonic vibrator. I) driving the ultrasonic vibrator while changing the driving frequency;
Ii) measuring the current consumption in the step i);
Iii) setting the driving frequency of step ii) as the optimum driving frequency of the ultrasonic vibrator when the maximum consumption current of step ii) is measured. The method of claim 2,
The driving method of the ultrasonic vibrator, characterized in that the step of changing the driving frequency of step i) is performed periodically. In the ultrasonic vibrator driving device that vibrates according to the driving frequency setting,
The driving device is an ultrasonic vibrator driving device, characterized in that the driving frequency is changed and the driving frequency is reset by measuring the current consumed while changing the driving frequency to find the driving frequency at the point when the current consumption is maximized.

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