CN106053614A - Improved electromagnetic ultrasonic transducer of LCL resonance circuit and component parameter design method thereof - Google Patents

Abstract

The invention discloses an improved electromagnetic ultrasonic transducer of an LCL resonance circuit. The electromagnetic ultrasonic transducer comprises a signal emitting part, a bias magnetic field, and a signal receiving part. The signal emitting part and the bias magnetic field react with each other to generate ultrasonic waves to detect the detected devices. The reflected ultrasonic waves can react with the bias magnetic field, the generated signals are received by the signal receiving part, the detection results can be obtained; the signal emitting part is composed of a signal emitting circuit, an impedance matching circuit, and an exciting coil circuit, and the impedance matching circuit is an LCL resonance circuit. The invention also discloses a design method of parameters of the components for the provided electromagnetic ultrasonic transducer. Through two grade resonance, a high voltage gain can be provided to an electromagnetic ultrasonic transducer, a transformer is not required, thus the problems of magnetic saturation and electromagnetic interference of transformer are solved; moreover, the generated pulse excitation signal is single, the detection precision is high; the direct current voltage source can be a lithium battery, and the electromagnetic ultrasonic transducer is portable.

Description

The electromagnet ultrasonic changer of modified model LCL resonance circuit and component parameter design thereof Method

Technical field

The present invention relates to nondestructive detecting field, particularly relate to the electromagnetic acoustic transducer of a kind of modified model LCL resonance circuit Can device and component parameter method for designing thereof.

Background technology

Along with the tremendous expansion of industrial automation, various equipment are used on a large scale, in use security hidden trouble The most greatly highlight, the such issues that of in order to eliminate, need to carry out equipment irregular carrying out flaw detection, therefore, not damaged is detected a flaw Technology develops rapidly.In not damaged inspection field, ultrasonic guided wave detection technology has the advantages such as propagation distance is remote, speed is fast, should The most wide by prospect.In ultrasonic guided wave detection technology, electromagnetic ultrasonic wave detection technique with its noncontact, high temperature resistant, without The advantage of couplant, one of leading edge developments technology becoming ultrasonic detecting technology.In electromagnetic ultrasonic wave detection technique, electromagnetism surpasses The pumping signal in acoustic wave excitation source needs to be high-frequency narrow-band wide pulse signal, and conventional art obtains high pressure mainly by transformator Gain, but this method can produce electromagnetic interference, and also transformator is the impulse type transformator with high conversion ratio, and this Planting transformator and do not only have magnetically saturated restriction, and need the protection circuit of complexity, bulky, cost is high, it is difficult to realize little Type portable set uses.

Summary of the invention

For solve above technical problem, the present invention provide a kind of modified model LCL resonance circuit electromagnet ultrasonic changer and Its excitation power supply component parameter method for designing.Utilize full-bridge inverter to produce impulse type square-wave signal, more improved type LCL is humorous The sinusoidal wave impulse-type excitation high-voltage signal that the two-stage resonance generation resonance free of circuit that shakes trails, in order to encourage electromagnetic acoustic transducer Components and parts flaw detection can be carried out by device generation ultrasound wave.

Technical scheme is as follows:

The electromagnet ultrasonic changer of a kind of modified model LCL resonance circuit, including signal emission part, bias magnetic field and signal Acceptance division, it it is critical only that: described signal emission part is by signal transmission circuit, impedance matching circuit and excitation coil circuit group Becoming, described signal transmission circuit produces rectangular pulse signal, and rectangular pulse is input stimulus after impedance matching circuit voltage gain Coil circuit produces alternating electromagnetic field, and the current vortex effect that alternating electromagnetic field and bias magnetic field produce produces launches ultrasound wave, should Transmitting ul-trasonic irradiation is on testee, and signal receiving part receives testee reflectance ultrasound ripple；

Described impedance matching circuit is LCL resonance circuit, by inductance L_S, inductance L_P, electric capacity C_pComposition, inductance L_SFront end Connect the first outfan of signal transmission circuit, obtain rectangular pulse signal, inductance L_SRear end serial capacitors C_pIt is followed by signal to launch Circuit the second outfan, inductance L_SRear end also meet inductance L_PFront end, inductance L_PThe input of rear termination excitation coil circuit.

Use said structure, be provided that the impulse-type excitation needed for higher electromagnetic acoustic wave transducer by two-stage resonance Voltage, it is not necessary to transformator, the problem not having transformator magnetic saturation and electromagnetic interference；The pulse excitation signal frequency spectrum produced is single, Accuracy of detection is high.

Further, described inductance L_SThrough resistance R₁With inductance L_PConnect, in described excitation coil circuit, be provided with one For eliminating the resistance R of resonance hangover₂。

Use said structure, resistance R₁With resistance R₂Can eliminate resonance conditions of streaking, the pumping signal that can make generation is always Higher hamonic wave, improves accuracy of detection.

Further, described signal transmission circuit includes direct voltage source, drive circuit and full-bridge inverter, described directly Stream voltage source connects described full-bridge inverter, and described drive circuit drives full-bridge inverter output rectangular pulse signal, described full-bridge The output termination LCL resonance circuit of inverter.

Use said structure, good rectangular pulse signal can be produced.

Further, ultrasonic transducer is by lithium battery power supply.

Using said structure, lithium battery is easy to carry, and can realize the Miniaturized portable equipment of electromagnetic acoustic wave transducer Use.

The component parameter method for designing of the electromagnetic acoustic wave transducer of modified model LCL resonance circuit, its it is critical only that by Carry out according to step once:

Step 1, selected gain factor λ and resonance frequency omega_R, wherein λ is positive integer；

Step 2, detect equivalent inductance L of excitation coil circuit₀And equivalent resistance R₀, by excitation coil circuit equivalent Become by resistance R₀, inductance L₀, electric capacity C₀Composition equivalent circuit, then the electromagnet ultrasonic changer of modified model LCL resonance circuit etc. Effect circuit is: inductance L_SFront end connect signal transmission circuit the first outfan, obtain rectangular pulse signal, inductance L_SAfter End serial capacitors C_pIt is followed by signal transmission circuit the second outfan, inductance L_SRear end also through resistance R₁Meet inductance L_PFront end, inductance L_PRear end serial capacitors C₀It is followed by signal transmission circuit the second outfan, inductance L_PRear end is also through resistance R₂Meet inductance L₀Front end, inductance L₀Rear end is through resistance R₀Connect signal transmission circuit the second outfan；

The prime of new equivalent circuit is considered as by inductance L_SWith electric capacity C_pThe LC resonance of composition, rear class can be seen by electricity Sense L_P, electric capacity C₀And inductance L₀The LCL resonance of composition；

Step 3, for rear class LCL resonance, its input impedance

$Z_{LCL}=\frac{{\mathrm{j\ωL}}_p-{\mathrm{j\ω}}^3{L}_0{L}_p{C}_0+{\mathrm{j\ωL}}_0+R_0}{1-{\mathrm{\ω}}^2{L}_0{C}_0}$

Because circuit is operated in resonant condition, so the imaginary part of input impedance is 0, i.e.

$\mathrm{Im}\[Z_{LCL}\]=\frac{{\mathrm{j\ωL}}_p-{\mathrm{j\ω}}^3{L}_p{L}_0{C}_0+{\mathrm{j\ωL}}_0}{1-{\mathrm{\ω}}^2{L}_0{C}_0}=0$

Thus can obtain resonant frequency:

${\mathrm{\ω}}_R=\sqrt{\frac{L_p+L_0}{L_p{L}_0{C}_0}}$

For the ease of determining the parameter of LCL resonance, take L_P/L₀=λ, then can get inductance L_P, electric capacity C₀Parameter calculate public affairs Formula is as follows:

$C_0=\frac{1+\mathrm{\λ}}{L_0{{\mathrm{\ω}}_R}^2}$

Step 4, the gain factor of whole excitation power supply are λ, it may be assumed that L_S/L_P=λ can be in the hope of inductance L with this_SParameter value；

Step 5, for prime LC resonance because the resonant frequency of whole gain circuitry needs to ensure consistent, thus according to Below equation can obtain electric capacity C_pParameter value:

${\mathrm{\ω}}_R=\frac{1}{\sqrt{L_s{C}_p}},L_s{C}_p=\frac{1}{{{\mathrm{\ω}}_R}^2}$

Step 6, the parameter tried to achieve according to step 1-6 put up circuit, and obtain the voltage waveform of output；

Step 7, try to achieve resistance R according to the secondary harmonic amplitude of output voltage waveforms and the difference of triple-frequency harmonics amplitude₁And R₂ Parameter value.

Use said method, the parameter value of each components and parts can be set according to demand, it is to avoid parameter value sets inaccurate making One-tenth can not produce high voltage gain even can not produce voltage gain, or produces excessive resonance conditions of streaking.

Further, the span of described gain factor λ is: 0 < λ≤20.

Use above-mentioned restriction, be avoided that the serious resonance conditions of streaking of generation and system oscillation.

Further, described resistance R₂The span of resistance be 0 < R₂<5Ω。

Use above-mentioned restriction, be avoided that the amplitude reducing gain voltage.

Beneficial effect: use the present invention to be provided that the impulse-type excitation voltage needed for electromagnetic acoustic wave transducer, it is not necessary to become Depressor, the problem not having transformator magnetic saturation and electromagnetic interference；The pulse excitation signal frequency spectrum produced is single, and accuracy of detection is high； Direct voltage source can be the power supplys such as lithium battery, it is simple to carries.

Accompanying drawing explanation

Fig. 1 is the theory diagram of the present invention；

Fig. 2 is the theory diagram of signal emission part in Fig. 1；

Fig. 3 is the LCL resonance topological equivalent circuit diagram of the present invention；

Fig. 4 is the excitation power supply parameter designing flow chart of the present invention；

Fig. 5 is the simulation result figure that the present invention does not suppresses resonance to trail；

Fig. 6 is the resistance R of the present invention₁With resistance R₂Resistance determine figure；

Fig. 7 is the simulated effect figure that the present invention suppresses resonance to trail；

Fig. 8 is present invention experiment effect figure when inputting 50V.

Detailed description of the invention

Below in conjunction with embodiment and accompanying drawing, the invention will be further described.

As shown in Figure 1-2, the electromagnet ultrasonic changer of a kind of modified model LCL resonance circuit, bias including signal emission part Magnetic field and signal receiving part, signal emission part produces alternating electromagnetic field, and the current vortex effect produced with bias magnetic field produces super Sound wave, propagates in ultrasound wave measured device in a certain direction, and when running into defect, portion of ultrasonic sound wave can be reflected back toward signal and receive Portion, then with bias magnetic field produce current vortex effect produce alternating magnetic field, by analyze signal receiving part receive ultrasonic Ripple, just can be accurately detected defect.

Described signal emission part is made up of signal transmission circuit, impedance matching circuit and excitation coil, and signal launches electricity Road produces impulse type square-wave signal, and impulse type square-wave signal, through impedance matching circuit voltage gain, obtains impulse-type excitation high Pressure signal, in impulse-type excitation high-voltage signal input stimulus coil, excitation coil produces alternating electromagnetic field.

Described signal transmission circuit is met institute by direct voltage source, drive circuit and full-bridge inverter, described direct voltage source Stating full-bridge inverter, described drive circuit drives full-bridge inverter output impulse type square-wave signal, described direct voltage source and driving Galvanic electricity road is by lithium battery power supply.

Described impedance matching circuit is LCL resonance circuit, by inductance L_S, inductance L_P, electric capacity C_pComposition, inductance L_SFront end Connect signal transmission circuit the first outfan, obtain rectangular pulse signal, inductance L_SRear end serial capacitors C_pIt is followed by signal and launches electricity Road the second outfan, inductance L_SRear end also meet inductance L_PFront end, inductance L_PThe input of rear termination excitation coil circuit.

For eliminating resonance conditions of streaking, described inductance L_SThrough resistance R₁With inductance L_PConnect, set in described excitation coil circuit It is equipped with one for the resistance R eliminating resonance hangover₂。

As shown in figures 3-8, the excitation power supply component parameter design of the electromagnet ultrasonic changer of modified model LCL resonance circuit Method, is carried out according to step once:

Step 1, selected gain factor λ and resonance frequency omega_R, wherein λ is positive integer, drags for avoiding producing serious resonance Tail phenomenon and system oscillation, the span of described gain factor λ is: 0 < λ≤20.

Step 2, detect equivalent inductance L of excitation coil circuit with electric impedance analyzer₀And equivalent resistance R₀, will excitation Coil circuit equivalence becomes by resistance R₀, inductance L₀, electric capacity C₀The equivalent circuit of composition, then the electromagnetism of modified model LCL resonance circuit surpasses The equivalent circuit of sonic transducer is: inductance L_SFront end connect signal transmission circuit the first outfan, obtain rectangular pulse letter Number, inductance L_SRear end serial capacitors C_pIt is followed by signal transmission circuit the second outfan, inductance L_SRear end also through resistance R₁Connect inductance L_PFront end, inductance L_PRear end serial capacitors C₀It is followed by signal transmission circuit the second outfan, inductance L_PRear end is also through resistance R₂Connect electricity Sense L₀Front end, inductance L₀Rear end is through resistance R₀Connect signal transmission circuit the second outfan.

The prime of new equivalent circuit is considered as one by inductance L_SWith electric capacity C_pThe LC resonance of composition, rear class can be seen By inductance L_P, electric capacity C₀And inductance L₀The LCL resonance of composition.

Step 3, for rear class LCL resonance, its input impedance

$Z_{LCL}=\frac{{\mathrm{j\&omega;L}}_p-{\mathrm{j\&omega;}}^3{L}_0{L}_p{C}_0+{\mathrm{j\&omega;L}}_0+R_0}{1-{\mathrm{\&omega;}}^2{L}_0{C}_0}$

Because circuit is operated in resonant condition, so the imaginary part of input impedance is 0, i.e.

$\mathrm{Im}\&lsqb;Z_{LCL}\&rsqb;=\frac{{\mathrm{j\&omega;L}}_p-{\mathrm{j\&omega;}}^3{L}_p{L}_0{C}_0+{\mathrm{j\&omega;L}}_0}{1-{\mathrm{\&omega;}}^2{L}_0{C}_0}=0$

Thus can obtain resonant frequency:

${\mathrm{\&omega;}}_R=\sqrt{\frac{L_p+L_0}{L_p{L}_0{C}_0}}$

For the ease of determining the parameter of LCL resonance, take L_P/L₀=λ, then can get inductance L_PParameter value, electric capacity C₀Ginseng Number computing formula is as follows:

$C_0=\frac{1+\mathrm{\&lambda;}}{L_0{{\mathrm{\&omega;}}_R}^2}$

Step 4, the gain factor of whole circuit are λ, it may be assumed that L_S/L_P=λ can be in the hope of inductance L with this_SParameter value；

Step 5, for prime LC resonance because the resonant frequency of whole gain circuitry needs to ensure consistent, thus according to Below equation can obtain electric capacity C_pParameter value:

${\mathrm{\&omega;}}_R=\frac{1}{\sqrt{L_s{C}_p}},L_s{C}_p=\frac{1}{{{\mathrm{\&omega;}}_R}^2}$

Step 6, the parameter tried to achieve according to step 1-6 are put up circuit, and are detected the voltage waveform of output；

Step 7, try to achieve resistance R according to the secondary harmonic amplitude of output voltage waveforms and the difference of triple-frequency harmonics amplitude₁With Resistance R₂Parameter value, for avoiding resistance R₂Affect voltage gain, resistance R₂Span be 0 < R₂<5Ω。

It is last it should be noted that foregoing description is only the preferred embodiments of the present invention, the ordinary skill people of this area Member, under the enlightenment of the present invention, on the premise of present inventive concept and claim, can make table as multiple types Show, within such conversion each falls within protection scope of the present invention.

Claims (7)

1. an electromagnet ultrasonic changer for modified model LCL resonance circuit, connects including signal emission part, bias magnetic field and signal Receipts portion, it is characterised in that: described signal emission part is by signal transmission circuit, impedance matching circuit and excitation coil circuit group Becoming, described signal transmission circuit produces rectangular pulse signal, and rectangular pulse is input stimulus after impedance matching circuit voltage gain Coil circuit produces alternating electromagnetic field, and the current vortex effect that alternating electromagnetic field and bias magnetic field produce produces launches ultrasound wave, should Transmitting ul-trasonic irradiation, on testee, produces reflectance ultrasound ripple after running into the damage in testee, and signal receiving part connects Receive reflectance ultrasound ripple；

Described impedance matching circuit is LCL resonance circuit, by inductance L_S, inductance L_P, electric capacity C_pComposition, inductance L_SFront end connect letter First outfan of number radiating circuit, obtains rectangular pulse signal, inductance L_SRear end serial capacitors C_pIt is followed by signal transmission circuit Two outfans, inductance L_SRear end also meet inductance L_PFront end, inductance L_PThe input of rear termination excitation coil circuit.

The electromagnet ultrasonic changer of modified model LCL resonance circuit the most according to claim 1, it is characterised in that: described inductance L_S Through resistance R₁With inductance L_PConnect, be provided with one in described excitation coil circuit for the resistance R eliminating resonance hangover₂。

The electromagnet ultrasonic changer of modified model LCL resonance circuit the most according to claim 2, it is characterised in that: described signal Radiating circuit includes that direct voltage source, drive circuit and full-bridge inverter, described direct voltage source connect described full-bridge inverter Input, described drive circuit drives full-bridge inverter output impulse type square-wave signal.

The electromagnet ultrasonic changer of modified model LCL resonance circuit the most according to claim 1, it is characterised in that: electromagnetic acoustic Wave transducer is by lithium battery power supply.

5. the component parameter method for designing of the electromagnet ultrasonic changer of modified model LCL resonance circuit as claimed in claim 3, its It is characterised by carrying out according to step once:

Step 1, selected gain factor λ and resonance frequency omega_R, wherein λ is positive integer；

Step 2, detect equivalent inductance L of excitation coil circuit₀And equivalent resistance R₀, by excitation coil circuit equivalent become by Resistance R₀, inductance L₀, electric capacity C₀The equivalent circuit of composition, then the equivalent electric of the electromagnet ultrasonic changer of modified model LCL resonance circuit Lu Wei: inductance L_SFront end connect signal transmission circuit the first outfan, obtain rectangular pulse signal, inductance L_SRear end string Electric capacity C_pIt is followed by signal transmission circuit the second outfan, inductance L_SRear end also through resistance R₁Meet inductance L_PFront end, inductance L_PAfter End serial capacitors C₀It is followed by signal transmission circuit the second outfan, inductance L_PRear end is also through resistance R₂Meet inductance L₀Front end, inductance L₀After End is through resistance R₀Connect signal transmission circuit the second outfan；

The prime of new equivalent circuit is considered as one by inductance L_SWith electric capacity C_pThe LC resonance of composition, rear class can be seen by electricity Sense L_P, electric capacity C₀And inductance L₀The LCL resonance of composition；

Step 3, for rear class LCL resonance, its input impedance

$Z_{LCL}=\frac{{\mathrm{j\&omega;L}}_p-{\mathrm{j\&omega;}}^3{L}_0{L}_p{C}_0+{\mathrm{j\&omega;L}}_0+R_0}{1-{\mathrm{\&omega;}}^2{L}_0{C}_0}$

Because circuit is operated in resonant condition, so the imaginary part of input impedance is 0, i.e.

$\mathrm{Im}\&lsqb;Z_{LCL}\&rsqb;=\frac{{\mathrm{j\&omega;L}}_p-{\mathrm{j\&omega;}}^3{L}_p{L}_0{C}_0+{\mathrm{j\&omega;L}}_0}{1-{\mathrm{\&omega;}}^2{L}_0{C}_0}=0$

Thus can obtain resonant frequency:

${\mathrm{\&omega;}}_R=\sqrt{\frac{L_p+L_0}{L_p{L}_0{C}_0}}$

For the ease of determining the parameter of LCL resonance, take L_P/L₀=λ, then can get inductance L_P, electric capacity C₀Parameter calculation formula such as Under:

$C_0=\frac{1+\mathrm{\&lambda;}}{L_0{{\mathrm{\&omega;}}_R}^2}$

Step 4, the gain factor of whole circuit are λ, it may be assumed that L_S/L_P=λ can be in the hope of inductance L with this_SParameter value；

Step 5, for prime LC resonance, because the resonant frequency of whole gain circuitry needs to ensure consistent, so according to following Formula can obtain electric capacity C_pParameter value:

${\mathrm{\&omega;}}_R=\frac{1}{\sqrt{L_s{C}_p}},L_s{C}_p=\frac{1}{{{\mathrm{\&omega;}}_R}^2}$

Step 6, the parameter tried to achieve according to step 1-6 put up analogue simulation circuit, and obtain the voltage waveform of output；

Step 7, according to output the secondary harmonic amplitude of voltage waveform and the difference of triple-frequency harmonics amplitude try to achieve resistance R₁And R₂'s Parameter value.

The component parameter method for designing of the electromagnet ultrasonic changer of modified model LCL resonance circuit the most according to claim 5, It is characterized in that: the span of described gain factor λ is: 0 < λ≤20.

The component parameter method for designing of the electromagnet ultrasonic changer of modified model LCL resonance circuit the most according to claim 5, It is characterized in that: described resistance R₂The span of resistance is 0 < R₂<5。