阅读说明：本技术 一种超声换能器快速激励装置及控制方法 (Ultrasonic transducer rapid excitation device and control method ) 是由 张喻 王承成 杨涛 杨红幸 陈�胜 于 2020-07-22 设计创作，主要内容包括：本发明提出了一种超声换能器快速激励装置及控制方法,通过电压比较器将变压器副边反射回变压器原边的电压与设定电压比较,比较结果反馈给频率发生器,频率发生器根据比较结果调整下一次输出的方波频率,可以根据不同的充电电容电压,产生不同频率的方波,进而使得充电时间与充电电容电压相匹配,在充电过程中,没有等待的时间,提高了超声波换能器的激励速度；通过电压比较器得知充电循环的开始和结束时间,不论充电电容电压的高或低,都能在一个充电循环完成后立即启动下一个充电循环,中间没有等待的时间,从而大大提高了换能器的激励速度。(The invention provides a rapid excitation device of an ultrasonic transducer and a control method, wherein a voltage comparator is used for comparing the voltage reflected by a secondary side of a transformer to a primary side of the transformer with a set voltage, a comparison result is fed back to a frequency generator, the frequency generator adjusts the frequency of a square wave output next time according to the comparison result, square waves with different frequencies can be generated according to different charging capacitor voltages, so that the charging time is matched with the charging capacitor voltage, no waiting time exists in the charging process, and the excitation speed of the ultrasonic transducer is improved; the starting time and the ending time of the charging cycle are known through the voltage comparator, no matter whether the voltage of the charging capacitor is high or low, the next charging cycle can be started immediately after the completion of one charging cycle, and no waiting time exists in the middle, so that the excitation speed of the transducer is greatly improved.)

1. The utility model provides an ultrasonic transducer rapid excitation device which includes frequency generator, duty ratio controller, switch tube driver, switch tube, transformer and charging capacitor, its characterized in that: the device also comprises a voltage comparator;

the output end of the frequency generator is electrically connected with the input end of the switching tube driver through the duty ratio controller, the output end of the switching tube driver is electrically connected with the control end of the switching tube, one end of the switching tube is electrically connected with the low-voltage end of the primary side of the transformer, the other end of the switching tube is grounded, the high-voltage end of the primary side of the transformer is electrically connected with the power supply, the high-voltage end of the secondary side of the transformer is electrically connected with one end of the charging capacitor, the other end of the charging capacitor is grounded, and the low-voltage end of the secondary side of the; the input end of the voltage comparator is electrically connected with the low-voltage end of the primary side of the transformer, and the output end of the voltage comparator is electrically connected with the feedback end of the frequency generator.

2. The ultrasonic transducer rapid excitation device of claim 1, wherein: the voltage comparator includes: operational amplifiers and resistors R1-R4;

the low-voltage end of the primary side of the transformer is electrically connected with the non-inverting input end of the operational amplifier through a resistor R2, one end of a resistor R4 is electrically connected with the non-inverting input end of the operational amplifier, and the other end of the resistor R4 is grounded;

the power supply is electrically connected with the inverting input end of the operational amplifier through a resistor R1, one end of a resistor R3 is electrically connected with the inverting input end of the operational amplifier, and the other end of the resistor R3 is grounded.

3. The ultrasonic transducer rapid excitation device of claim 1, wherein: the device also comprises a single-phase current valve;

the single-phase current valve is connected between the high-voltage end of the secondary side of the transformer and the sound measuring tube in series.

4. The ultrasonic transducer rapid excitation device of claim 1, wherein: the device also comprises a change-over switch;

the input end of the change-over switch is electrically connected with one end of the charging capacitor, and the other end of the change-over switch is electrically connected with a plurality of external ultrasonic transducers respectively.

5. A control method of an ultrasonic transducer rapid excitation device is characterized in that: the method comprises the following steps:

S1, the frequency generator generates a square wave signal and sends the square wave signal to the duty ratio controller, the duty ratio controller adjusts the duty ratio of the square wave signal, and the adjusted square wave signal drives the switching tube through the switching tube driver;

s2, when the switch tube is conducted, the charging cycle begins, and the current continuously increases due to the inductance characteristic of the transformer; when the switching tube is disconnected, the primary side current of the transformer suddenly changes to 0, the energy accumulated by the primary side inductance of the transformer is not discharged, the transformer enters a flyback mode, the secondary side of the transformer charges the charging capacitor through the single-phase current valve, and meanwhile, the voltage of the secondary side of the transformer is reflected to the primary side of the transformer;

s3, leading out a line from the low-voltage end of the primary side of the transformer to the non-inverting input end of the voltage comparator, when the switching tube is disconnected, the voltage comparator compares the voltage reflected by the secondary side of the transformer to the primary side of the transformer with a set voltage, the comparison result is fed back to the frequency generator, and the frequency generator adjusts the frequency of the square wave output next time according to the comparison result;

and S4, when the current of the secondary side of the transformer is 0, the voltage reflected by the secondary side of the transformer to the primary side of the transformer is 0, the output result of the voltage comparator jumps, the charging cycle is finished, the frequency generator is started immediately, and the next charging cycle starts.

6. The control method of an ultrasonic transducer rapid excitation device according to claim 5, characterized in that: in S1, the switching tube is turned on when the square wave is at a high level, and is turned off when the square wave is at a low level.

7. The control method of an ultrasonic transducer rapid excitation device according to claim 5, characterized in that: in S2, when the switching tube is turned on, the voltage comparator compares the voltage at the low-voltage end of the primary side of the transformer with a preset voltage, the comparison result is fed back to the frequency generator, and the duty ratio controller adjusts the duty ratio of the next output square wave according to the comparison result, so that the voltage of the transformer is quickly increased.

Technical Field

The invention relates to the technical field of foundation pile ultrasonic detectors, in particular to a rapid excitation device of an ultrasonic transducer and a control method.

Background

The main methods for detecting the pile foundation include a static load test, a core drilling method, a low strain method, a high strain method, a sound wave transmission method and the like, wherein the sound wave transmission method is generally applied as an important mode for detecting and evaluating the integrity of the foundation pile. The acoustic transmission method generally adopts a foundation pile ultrasonic detector, and the currently mainstream foundation pile ultrasonic detector in China mainly comprises the following parts: 1. an ultrasonic transducer; 2. an ultrasonic detection host; 3. a depth counting encoder. The specific operation process is as follows: in the field detection process, a detection person operates the ultrasonic detection host, starts an ultrasonic transducer excitation device and an acquisition module in the ultrasonic detection host to work, and simultaneously, the depth counter records the current depth of the ultrasonic transducer in real time by pulling the cable of the ultrasonic transducer, so that the defect position can be conveniently positioned in the subsequent analysis and treatment.

As shown in fig. 1, in the ultrasonic detection technology, if three acoustic pipes are embedded, data detection of three sections needs to be completed simultaneously, and the ultrasonic transducer fast excitation device needs to excite an ultrasonic transducer at least 2 times; if four sound measuring tubes are buried, data detection of six sections needs to be completed simultaneously, and the ultrasonic transducer rapid excitation device needs to excite the ultrasonic transducer at least 3 times; if five sounding pipes are buried, data detection of ten sections needs to be completed simultaneously, and the ultrasonic transducer rapid excitation device needs to excite the ultrasonic transducer at least 4 times. With the continuous rise of large buildings, expressways and the like, the pile body with large diameter is a necessary trend, the more the acoustic pipes are embedded, in order not to influence the lifting speed, and therefore, requirements and challenges are brought to the excitation speed of the transducer. In the whole foundation pile detection process, the lifting speed of the ultrasonic transducer directly influences the detection efficiency and the operation experience. If the moving distance is 50mm according to the lifting speed of 1m/s, the time for completing the excitation of each measuring point needs to be within 20 ms. However, the charging of the 1-2uF large capacitor by the current mainstream excitation device needs more than 50ms-100ms, and can only reach about 70-80% of the preset charging voltage, if the charging voltage is required to reach or approach the preset voltage, the required charging time is multiplied, and the actual engineering application cannot be met. Therefore, in order to solve the above problems, the present invention provides a fast excitation device for an ultrasonic transducer and a control method thereof, which can increase the excitation speed of the ultrasonic transducer and meet the practical engineering application.

Disclosure of Invention

In view of this, the invention provides a fast excitation device and a control method for an ultrasonic transducer, which can improve the excitation speed of the ultrasonic transducer and meet the practical engineering application.

The technical scheme of the invention is realized as follows: the invention provides a rapid excitation device of an ultrasonic transducer, which comprises a frequency generator, a duty ratio controller, a switching tube driver, a switching tube, a transformer, a charging capacitor and a voltage comparator, wherein the frequency generator is connected with the switching tube driver;

the output end of the frequency generator is electrically connected with the input end of the switching tube driver through the duty ratio controller, the output end of the switching tube driver is electrically connected with the control end of the switching tube, one end of the switching tube is electrically connected with the low-voltage end of the primary side of the transformer, the other end of the switching tube is grounded, the high-voltage end of the primary side of the transformer is electrically connected with the power supply, the high-voltage end of the secondary side of the transformer is electrically connected with one end of the charging capacitor, the other end of the charging capacitor is grounded, and the low-voltage end of the secondary side of; the input end of the voltage comparator is electrically connected with the low-voltage end of the primary side of the transformer, and the output end of the voltage comparator is electrically connected with the feedback end of the frequency generator.

On the basis of the above technical solution, preferably, the voltage comparator includes: operational amplifiers and resistors R1-R4;

The low-voltage end of the primary side of the transformer is electrically connected with the non-inverting input end of the operational amplifier through a resistor R2, one end of a resistor R4 is electrically connected with the non-inverting input end of the operational amplifier, and the other end of the resistor R4 is grounded;

the power supply is electrically connected with the inverting input end of the operational amplifier through a resistor R1, one end of a resistor R3 is electrically connected with the inverting input end of the operational amplifier, and the other end of the resistor R3 is grounded.

On the basis of the technical scheme, the device preferably further comprises a single-phase current valve;

the single-phase current valve is connected in series between the high-voltage end of the secondary side of the transformer and the sound measuring tube.

On the basis of the above technical solution, preferably, the device further comprises a switch;

the input end of the change-over switch is electrically connected with one end of the charging capacitor, and the other end of the change-over switch is electrically connected with a plurality of external ultrasonic transducers respectively.

In another aspect, the present invention provides a method for controlling a fast excitation device of an ultrasonic transducer, including the following steps:

s1, the frequency generator generates a square wave signal and sends the square wave signal to the duty ratio controller, the duty ratio controller adjusts the duty ratio of the square wave signal, and the adjusted square wave signal drives the switching tube through the switching tube driver;

S2, when the switch tube is conducted, the charging cycle begins, and the current continuously increases due to the inductance characteristic of the transformer; when the switching tube is disconnected, the primary side current of the transformer suddenly changes to 0, the energy accumulated by the primary side inductance of the transformer is not discharged, the transformer enters a flyback mode, the secondary side of the transformer charges the charging capacitor through the single-phase current valve, and meanwhile, the voltage of the secondary side of the transformer is reflected to the primary side of the transformer;

s3, leading out a line from the low-voltage end of the primary side of the transformer to the non-inverting input end of a voltage comparator, comparing the voltage reflected by the secondary side of the transformer back to the primary side of the transformer with a set voltage by the voltage comparator, feeding the comparison result back to a frequency generator, and adjusting the frequency of the square wave output next time by the frequency generator according to the comparison result;

and S4, when the current of the secondary side of the transformer is 0, the voltage reflected by the secondary side of the transformer to the primary side of the transformer is 0, the output result of the voltage comparator jumps, the charging cycle is finished, the frequency generator is started immediately, and the next charging cycle starts.

Based on the above technical solution, preferably, in S1, the switching tube is turned on when the square wave is at a high level, and the switching tube is turned off when the square wave is at a low level.

On the basis of the above technical solution, preferably, in S2, when the switching tube is turned on, the voltage comparator compares the voltage at the low-voltage end of the primary side of the transformer with a preset voltage, the comparison result is fed back to the frequency generator, and the duty ratio controller adjusts the duty ratio of the square wave output next time according to the comparison result, so that the voltage of the transformer is boosted quickly.

Compared with the prior art, the ultrasonic transducer rapid excitation device and the control method have the following beneficial effects:

(1) the voltage reflected by the secondary side of the transformer back to the primary side of the transformer is compared with the set voltage through the voltage comparator, the comparison result is fed back to the frequency generator, the frequency generator adjusts the frequency of the square wave output next time according to the comparison result, the square waves with different frequencies can be generated according to different charging capacitor voltages, further the charging time is matched with the charging capacitor voltages, no waiting time exists in the charging process, and the excitation speed of the ultrasonic transducer is improved;

(2) the starting time and the ending time of the charging cycle are known through the voltage comparator, no matter whether the voltage of the charging capacitor is high or low, the next charging cycle can be started immediately after the completion of one charging cycle, and no waiting time exists in the middle, so that the excitation speed of the transducer is greatly improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic cross-sectional view of a corresponding process for embedding different numbers of acoustic pipes in an ultrasonic testing technique;

fig. 2 is a structural diagram of a rapid excitation device of an ultrasonic transducer according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.