Differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device

Abstract

The present application discloses a differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device, which relates to the electromagnetic ultrasonic phased array detection technology field. The device includes: a transmitting unit array, a sensor array and a receiving unit array. The transmitting unit array includes a plurality of transmitting units, which are floating differential transmitting units, and include a plurality of transformers connected in series. The sensor array includes a plurality of array elements, which are single-ended electromagnetic ultrasonic sensors. The receiving unit array includes a plurality of receiving units, which are floating differential receiving units. The transmitting unit transmits a pulse excitation signal to excite the array element to work. The array element completes the electro-magnetic-acoustic transduction, generates ultrasonic waves to detect the measured component, and converts the detection echo into a detection electrical signal. The receiving unit performs signal conditioning on the detection electrical signal to obtain the conditioned electrical signal. The device of the present application can reduce the volume, is simple to manufacture, and improves the overall signal-to-noise ratio.

Description

Technical Field

[0001] The present application relates to the technical field of electromagnetic ultrasonic phased array detection, and in particular to a differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device. Background Art

[0002] Electromagnetic ultrasonic phased array detection has the advantages of non-contact and no need for grinding, and has a wider range of applications than piezoelectric ultrasonic phased array detection. However, due to the high transducer efficiency of the piezoelectric ultrasonic phased array, the required excitation voltage is low, the signal echo amplifier gain is small, and the implementation difficulty is low. The transducer of the electromagnetic ultrasonic phased array uses a coil to achieve electro-magnetic-acoustic transduction, and the transducer efficiency is low. Its excitation requires a large excitation voltage and a high-gain and high-signal-to-noise ratio receiving signal conditioning circuit. In addition, the coil structure is very easy to receive noise and interference signals in the air. The electromagnetic ultrasonic signal often requires multiple averaging to obtain a good signal-to-noise ratio. Therefore, the electromagnetic ultrasonic phased array is more difficult to implement than the piezoelectric ultrasonic phased array. In summary, compared with the piezoelectric ultrasonic phased array, the electromagnetic ultrasonic phased array requires a larger excitation voltage and a receiving signal conditioning circuit with a higher signal-to-noise ratio.

[0003] At present, the traditional electromagnetic ultrasonic phased array device includes full single-ended type and full differential type. The full single-ended type includes a single-ended transmitting unit, a single-ended electromagnetic ultrasonic sensor and a single-ended receiving unit. In order to increase the excitation voltage, more complex and higher-demand electronic devices are required. This method will greatly increase the volume and power consumption of the instrument. In the case of multiple channels, the volume of the instrument will be very bulky and high power consumption. In addition, due to the inherent characteristics of the full single-ended type, its signal-to-noise ratio is very low and cannot achieve the purpose of improving the signal-to-noise ratio. The full differential type includes a differential transmitting unit, a differential electromagnetic ultrasonic sensor and a differential receiving unit. Compared with the full single-ended type, the signal-to-noise ratio can be improved by using a differential transmitting unit to excite the differential electromagnetic ultrasonic sensor and cooperate with a differential receiving unit. However, the differential transmitting unit usually uses a high-voltage power supply and a differential power amplifier, and the differential receiving unit usually uses a differential amplifier circuit. In order to increase the excitation voltage, the structure of the high-voltage power supply and the differential power amplifier will also become very complex and large in volume. In addition, the use of a full differential structure will make it very difficult to manufacture. Summary of the invention

[0004] The purpose of the present application is to provide a differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device, which can reduce the volume, is simple to manufacture, and improves the overall signal-to-noise ratio.

[0005] To achieve the above objectives, this application provides the following solutions.

[0006] In a first aspect, the present application provides a differential high-power excitation and high signal-to-noise ratio reception electromagnetic ultrasonic phased array device, wherein the differential high-power excitation and high signal-to-noise ratio reception electromagnetic ultrasonic phased array device comprises: a transmitting unit array, a sensor array and a receiving unit array.

[0007] The transmitting unit array comprises a plurality of transmitting units, wherein the transmitting units are floating differential transmitting units, and the transmitting units comprise a plurality of transformers connected in series.

[0008] The sensor array includes a plurality of array elements, and the array elements are single-ended electromagnetic ultrasonic sensors.

[0009] The receiving unit array includes a plurality of receiving units, and the receiving units are floating differential receiving units.

[0010] The transmitting unit, array element and receiving unit correspond one to one; the transmitting unit is connected to the array element, and the transmitting unit is used to transmit a pulse excitation signal to stimulate the array element to work; the array element is used to complete electro-magnetic-acoustic transduction, generate ultrasonic waves to detect the components under test, and convert the detection echoes into detection electrical signals; the array element is connected to the receiving unit, and the receiving unit is used to perform signal conditioning on the detection electrical signals to obtain conditioned electrical signals.

[0011] Optionally, the first end of the primary coil of each transformer is connected to a first switching tube, the middle tap of each transformer is connected to a DC power supply, the second end of the primary coil of each transformer is connected to a second switching tube, all first switching tubes are connected to the negative input terminal of the transmitting unit, and all second switching tubes are connected to the positive input terminal of the transmitting unit. The negative input terminal is used to input a first pulse signal, and the positive input terminal is used to input a second pulse signal. The first pulse signal and the second pulse signal have the same amplitude and opposite polarity.

[0012] The first end of the secondary coil of the first transformer is connected to the positive output end of the transmitting unit, the first end of the secondary coil of the i-th transformer is connected to the second end of the secondary coil of the i-1-th transformer, i=2, 3, ..., n, n is the total number of transformers, and the second end of the secondary coil of the n-th transformer is connected to the negative output end of the transmitting unit.

[0013] The positive output end of the transmitting unit is connected to the in-phase end of the array element, and the negative output end of the transmitting unit is connected to the inverting end of the array element.

[0014] Optionally, the transmitting unit further includes: a first impedance matching circuit and a second impedance matching circuit.

[0015] The first impedance matching circuit is located between the first end of the secondary coil of the first transformer and the positive output end of the transmitting unit, the first end of the first impedance matching circuit is connected to the first end of the secondary coil of the first transformer, and the second end of the first impedance matching circuit is connected to the positive output end of the transmitting unit.

[0016] The second impedance matching circuit is located between the second end of the secondary coil of the nth transformer and the negative output end of the transmitting unit, the first end of the second impedance matching circuit is connected to the second end of the secondary coil of the nth transformer, and the second end of the second impedance matching circuit is connected to the negative output end of the transmitting unit.

[0017] Optionally, the receiving unit includes a balance compensation circuit, a clamping circuit module, an isolation circuit, a filtering compensation amplifier circuit and an amplifier circuit which are connected in sequence.

[0018] Optionally, the balance compensation circuit includes a capacitor and an inductance of a coil in an array element, a first end of the capacitor is connected to an in-phase end of the array element, and a second end of the capacitor is connected to an in-phase end of the array element.

[0019] The clamping circuit module includes a first clamping circuit and a second clamping circuit, the first clamping circuit is connected to a first end of the capacitor, and the second clamping circuit is connected to a second end of the capacitor.

[0020] The isolation circuit includes a first buffer and a second buffer; the first input end of the first buffer is connected to the output end of the first clamping circuit, and the second input end of the first buffer is connected to the output end of the first buffer; the first input end of the second buffer is connected to the output end of the second clamping circuit, and the second input end of the second buffer is connected to the output end of the second buffer.

[0021] The filtering compensation amplifier circuit includes a differential filter, an inductor, a first amplifier and a second amplifier; the first input end of the differential filter is connected to the output end of the first buffer, and the second input end of the differential filter is connected to the output end of the second buffer; the first end of the inductor is respectively connected to the first output end of the differential filter and the input end of the first amplifier; the second end of the inductor is respectively connected to the second output end of the differential filter and the input end of the second amplifier.

[0022] The amplifying circuit comprises a differential amplifier; a first input end of the differential amplifier is connected to an output end of the first amplifier, and a second input end of the differential amplifier is connected to an output end of the second amplifier.

[0023] Optionally, the first clamping circuit includes a first resistor and a first diode group, the first diode group includes a first diode and a second diode, the first end of the first resistor is connected to the first end of the capacitor, the second end of the first resistor is respectively connected to the anode of the first diode and the cathode of the second diode, and the cathode of the first diode is connected to the anode of the second diode.

[0024] The second clamping circuit includes a second resistor and a second diode group, the second diode group includes a third diode and a fourth diode, the first end of the second resistor is connected to the second end of the capacitor, the second end of the second resistor is respectively connected to the anode of the third diode and the cathode of the fourth diode, and the cathode of the third diode is connected to the anode of the fourth diode.

[0025] There are multiple filtering compensation amplifier circuits.

[0026] Optionally, the differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device also includes: a phased module, connected to the transmitting unit array, used to excite several transmitting units in the transmitting unit array according to preset working parameters and delay rules, so that the transmitting units emit pulse excitation signals; the working parameters include the amplitude and frequency of the excitation waveform, and the delay rule includes the delay sequence and delay time.

[0027] Optionally, the differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device also includes: an analog-to-digital converter array, including a plurality of analog-to-digital converters, and the analog-to-digital converters correspond one-to-one to the receiving units; the analog-to-digital converters are connected to the receiving units, and the analog-to-digital converters are used to perform analog-to-digital conversion on the conditioned electrical signal output by the receiving unit to obtain a digital electrical signal.

[0028] Optionally, the differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device also includes: a data processing module, connected to the analog-to-digital converter array, used to perform imaging based on all digital electrical signals obtained by the analog-to-digital converter array to obtain detection results of the tested components.

[0029] Optionally, the differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device also includes: a main control module, which is connected to the phase control module and the data processing module respectively, and is used to send working parameters and delay rules to the phase control module, and receive detection results obtained by the data processing module; a display module, which is connected to the main control module, and is used to display the detection results and realize human-computer interaction.

[0030] According to the specific embodiments provided in this application, this application has the following technical effects.

[0031] The present application provides a differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device, the device comprising: a transmitting unit array, a sensor array and a receiving unit array, the transmitting unit array comprising a plurality of transmitting units, the transmitting unit being a floating differential transmitting unit, comprising a plurality of transformers connected in series, the sensor array comprising a plurality of array elements, the array elements being single-ended electromagnetic ultrasonic sensors, the receiving unit array comprising a plurality of receiving units, the receiving units being floating differential receiving units, the transmitting units, the array elements and the receiving units corresponding one to one, the transmitting unit being used to transmit a pulse excitation signal to excite the array elements to work, the array elements being used to complete electro-magnetic-acoustic transduction, generating ultrasonic waves to detect a component under test, and converting a detection echo into a detection electrical signal, the receiving unit being used to perform signal conditioning on the detection electrical signal to obtain a conditioned electrical signal. The present application designs a transmitting unit that adopts a floating differential transmitting unit, an array element that adopts a single-ended electromagnetic ultrasonic sensor, and a receiving unit that adopts a floating differential receiving unit, thereby utilizing a single-ended coil to achieve a differential effect. On the premise that the same signal-to-noise ratio improvement effect as the full differential type can be achieved, the circuit can be further simplified and the manufacturing difficulty can be reduced. The differential transmitting unit uses multiple transformers connected in series to increase the excitation voltage (i.e., a pulse excitation signal). Compared with the full single-ended and full differential types that require complex components to increase the excitation voltage, the size and power consumption can be reduced, and the disadvantage that a single-coil high-turns ratio transformer boost can only be used for low-frequency waveguide is overcome. Multiple low-turns transformers are connected in series to excite high-frequency signals in the megahertz range, and the detection blind area is small, further improving the overall signal-to-noise ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 A schematic structural diagram of a differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device provided in Example 1 of the present application.

[0034] Figure 2 A schematic diagram of the workflow of a differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device for detection provided in Example 1 of the present application.

[0035] Figure 3 A schematic diagram showing the software interface provided in Example 1 of the present application.

[0036] Figure 4 This is a schematic diagram showing the test results provided in Example 1 of the present application.

[0037] Figure 5 A schematic diagram of the principles of the transmitting unit and the receiving unit provided in Example 1 of the present application.

[0038] Figure 6 This is a schematic diagram of related signals when the transmitting unit provided in Example 1 of the present application is working; wherein, Figure 6 (a) is the first pulse signal of IN- input. Figure 6 (b) is the second pulse signal of IN+ input. Figure 6 (c) in the figure is the pulse signal output by a single transformer. Figure 6 (d) in the figure is the pulse signal output by n transformers.

[0039] Figure 7 This is a schematic diagram of a fully single-ended electromagnetic ultrasonic signal provided in Example 1 of the present application.

[0040] Figure 8 This is a schematic diagram of a single-ended electromagnetic ultrasonic sensor provided in Example 1 of the present application.

[0041] Fig. 9 This is a schematic diagram of a fully differential electromagnetic ultrasonic signal provided in Example 1 of the present application.

[0042] Fig.10 This is a schematic diagram of the differential electromagnetic ultrasonic sensor provided in Example 1 of the present application.

[0043] Fig.11 This is a schematic diagram of a partially single-ended and partially differential electromagnetic ultrasonic signal provided in Example 1 of the present application.

[0044] Figure numerals: 1-transmitting unit; 2-array element; 3-receiving unit; 4-component under test; 5-phase control module; 6-analog-to-digital converter; 7-data processing module; 8-main control module; 9-display module. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0046] Example 1.

[0047] This embodiment provides a differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device, such as Figure 1As shown, the differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device includes: a transmitting unit array, a sensor array and a receiving unit array.

[0048] The transmitting unit array includes a plurality of transmitting units 1, wherein the transmitting unit 1 is a floating differential transmitting unit, and the transmitting unit 1 includes a plurality of transformers connected in series. Figure 1 As shown, the transmitting unit array includes N identical transmitting units 1, namely Figure 1 The transmitting unit 1, the transmitting unit 2, the transmitting unit 3, ..., the transmitting unit N in the embodiment.

[0049] The sensor array includes a plurality of array elements 2, where the array elements 2 are single-ended electromagnetic ultrasonic sensors. The sensor array may also be referred to as a phased array electromagnetic ultrasonic sensor, such as Figure 1 As shown, the sensor array includes N identical array elements 2, which can be recorded as array element 1, array element 2, array element 3, ..., array element N.

[0050] The receiving unit array includes a plurality of receiving units 3, and the receiving units 3 are floating differential receiving units. Figure 1 As shown, the receiving unit array includes N identical receiving units 3, namely Figure 1 Receiving unit 1, receiving unit 2, receiving unit 3, ..., receiving unit N in.

[0051] There is a one-to-one correspondence between transmitting unit 1, array element 2 and receiving unit 3, that is, transmitting unit 1 is connected to array element 1, array element 1 is connected to receiving unit 1, transmitting unit 2 is connected to array element 2, array element 2 is connected to receiving unit 2, transmitting unit 3 is connected to array element 3, array element 3 is connected to receiving unit 3, and so on, transmitting unit N is connected to array element N, and array element N is connected to receiving unit N.

[0052] The transmitting unit 1 in the transmitting unit array is connected to the corresponding array element 2 in the sensor array, and the transmitting unit array is used to independently excite each array element 2 to work according to the working parameters and the delay law. The receiving unit 3 in the receiving unit array is connected to the corresponding array element 2 in the sensor array, and the receiving unit array is used to respectively amplify the detection electrical signal of each array element 2 to obtain a conditioned electrical signal (also called an electromagnetic ultrasonic signal).

[0053] Specifically, in this embodiment, the transmitting unit 1 is connected to the array element 2, and the transmitting unit 1 is used to transmit a pulse excitation signal (which is a high-voltage pulse excitation signal, and the specific voltage value is set according to needs) to stimulate the array element 2 to work. The array element 2 is used to complete the electro-magnetic-acoustic transduction, generate ultrasonic waves to detect the measured component 4, and convert the detection echo returned by the measured component 4 into a detection electrical signal. The array element 2 is connected to the receiving unit 3, and the receiving unit 3 is used to perform signal conditioning on the detection electrical signal to obtain the conditioned electrical signal.

[0054] The present embodiment provides an electromagnetic ultrasonic phased array device capable of achieving high-power excitation and high signal-to-noise ratio reception. The transmitting unit 1 adopts a floating differential transmitting unit, the array element 2 adopts a single-ended electromagnetic ultrasonic sensor, and the receiving unit 3 adopts a floating differential receiving unit, so that a differential effect is achieved by using a single-ended coil. On the premise of being able to achieve the same effect of improving the signal-to-noise ratio as a full differential type, the circuit can be further simplified and the manufacturing difficulty can be reduced. The differential transmitting unit adopts a plurality of transformers connected in series to increase the excitation voltage. Compared with the full single-ended type and the full differential type that require complex components to increase the excitation voltage, the size can be reduced, the power consumption can be reduced, and the overall signal-to-noise ratio can be improved.

[0055] like Figure 1 As shown, the differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device of this embodiment also includes: a phase control module 5, connected to the transmitting unit array, used to excite several transmitting units 1 in the transmitting unit array according to preset working parameters and delay rules, that is, to control one or more specified transmitting units 1 in the transmitting unit array to be excited according to the delay rule, so that the transmitting unit 1 emits a specified pulse excitation signal, and then uses the specified pulse excitation signal to drive the array element 2 in the sensor array to work, wherein the working parameters include the amplitude (which is the voltage value) and frequency of the excitation waveform, and the delay rule includes the delay sequence and the delay time. The working parameters and the delay rule can be sent to the phase control module 5 by the main control module 8.

[0056] like Figure 1 As shown, the differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device of this embodiment also includes: an analog-to-digital converter array, including a plurality of analog-to-digital converters 6, specifically including N identical analog-to-digital converters 6, namely Figure 1 Analog-to-digital converter 1, analog-to-digital converter 2, analog-to-digital converter 3, ..., analog-to-digital converter N.

[0057] The analog-to-digital converters 6 in the analog-to-digital converter array are connected to the receiving units 3 in the receiving unit array in a one-to-one correspondence. The analog-to-digital converter array is used to complete the analog-to-digital conversion of the conditioned electrical signal of each receiving unit 3 .

[0058] Specifically, the analog-to-digital converter 6 corresponds to the receiving unit 3 one by one, that is, the receiving unit 1 is connected to the analog-to-digital converter 1, the receiving unit 2 is connected to the analog-to-digital converter 2, the receiving unit 3 is connected to the analog-to-digital converter 3, and so on, the receiving unit N is connected to the analog-to-digital converter N. The analog-to-digital converter 6 is connected to the receiving unit 3, and the analog-to-digital converter 6 is used to perform analog-to-digital conversion on the conditioned electrical signal output by the receiving unit 3 to obtain a digital electrical signal.

[0059] like Figure 1As shown, the differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device of this embodiment also includes: a data processing module 7, which is connected to the analog-to-digital converter array, and is used to perform imaging based on all digital electrical signals obtained by the analog-to-digital converter array to obtain the detection result of the measured component 4 (which may be an imaging result), specifically completing the storage of the digital electrical signals of all analog-to-digital converters 6 and performing operations according to specified algorithms, such as fan scanning, full-focus imaging, etc., to obtain the detection result, and subsequently transmitting the detection result to the main control module 8.

[0060] like Figure 1 As shown, the differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device of this embodiment also includes: a main control module 8, which is connected to the phase control module 5 and the data processing module 7 respectively, and is used to send working parameters and delay rules to the phase control module 5, receive the detection results obtained by the data processing module 7, and is specifically responsible for parameter setting, logic control, working detection process control, detection result processing and output, etc. of the entire device.

[0061] The display module 9 is connected to the main control module 8 and is used to display the test results and realize human-computer interaction. It is specifically responsible for software interface display, test result display, human-computer interaction, etc.

[0062] like Figure 2 As shown, during the detection, the main control module 8 sets the parameters, inputs the working parameters and the delay rule into the phase control module 5, and the phase control module 5 excites the transmitting unit 1 based on the working parameters and the delay rule, so that the transmitting unit 1 emits a high-voltage pulse excitation signal, and uses the high-voltage pulse excitation signal to excite the array element 2 to work, and the array element 2 detects the component under test 4, and sends the obtained detection electrical signal to the receiving unit 3, and the receiving unit 3 performs signal conditioning on the detection electrical signal, and further performs analog-to-digital conversion through the analog-to-digital converter 6, and then sends the obtained digital electrical signal to the data processing module 7, and the data processing module 7 performs imaging according to the algorithm to obtain the detection result, and then performs defect interpretation based on the detection result and displays the detection result. Figure 3 As shown, it is a schematic diagram of the software interface display, such as Figure 4 As shown, it is a schematic diagram showing the detection results.

[0063] like Figure 5 As shown, in this embodiment, the structure of each transmitting unit 1 in the transmitting unit array is consistent, and the transmitting unit 1 is composed of a plurality of transformers T1~Tn (i.e. Figure 5 In this embodiment, the turns ratio of the primary coil to the secondary coil of each transformer is less than 3. The first end of the primary coil of each transformer is connected to a first switch tube (i.e. Figure 5Q1A, Q2A, Q3A, ..., QnA in the figure), the center tap of each transformer is connected to a DC power supply (i.e. Figure 5 The second end of each transformer's primary coil is connected to a second switch tube (i.e. Figure 5 Q1B, Q2B, Q3B, ..., QnB in the figure), the first switch tube and the second switch tube can both be MOSFET (Metal Oxide Semiconductor Field Effect Transistor), the two switch tubes are connected to the positive input terminal IN+ and the negative input terminal IN- respectively, and all the first switch tubes are connected to the negative input terminal IN- of the transmitting unit 1, such as Figure 5 As shown, Q1A, Q2A, Q3A, ..., QnA are all connected to the negative input terminal IN-, and all the second switch tubes are connected to the positive input terminal IN+ of the emission unit 1, as shown in FIG. Figure 5 As shown, Q1B, Q2B, Q3B, ..., QnB are all connected to the positive input terminal IN+, the negative input terminal IN- is used to input the first pulse signal, and the positive input terminal IN+ is used to input the second pulse signal. The first pulse signal and the second pulse signal have the same amplitude and opposite polarity.

[0064] The first end of the secondary coil of the first transformer T1 is connected to the positive output end of the transmitting unit 1 (i.e. Figure 5 + at element 2 in the array), the first end of the secondary coil of the i-th transformer is connected to the second end of the secondary coil of the i-1-th transformer, i=2, 3, ..., n, n is the total number of transformers, and the second end of the secondary coil of the n-th transformer Tn is connected to the negative output terminal of the transmitting unit 1 (i.e. Figure 5 - at element 2 in the middle array).

[0065] The positive output terminal of the transmitting unit 1 is connected to the in-phase terminal of the array element 2 , and the negative output terminal of the transmitting unit 1 is connected to the in-phase terminal of the array element 2 .

[0066] In this embodiment, the transmitting unit 1 further includes: a first impedance matching circuit ZA and a second impedance matching circuit ZB.

[0067] The first impedance matching circuit ZA is located between the first end of the secondary coil of the first transformer T1 and the positive output end of the transmitting unit 1, the first end of the first impedance matching circuit ZA is connected to the first end of the secondary coil of the first transformer T1, and the second end of the first impedance matching circuit ZA is connected to the positive output end of the transmitting unit 1.

[0068] The second impedance matching circuit ZB is located between the second end of the secondary coil of the nth transformer Tn and the negative output end of the transmitting unit 1, the first end of the second impedance matching circuit ZB is connected to the second end of the secondary coil of the nth transformer Tn, and the second end of the second impedance matching circuit ZB is connected to the negative output end of the transmitting unit 1.

[0069] At this time, the secondary coils of the transformers T1 to Tn are connected in series, and then connected to the first impedance matching circuit ZA and the second impedance matching circuit ZB respectively, and then output to the designated array element 2. Figure 6 As shown, Figure 6 (a) is the first pulse signal of IN- input. Figure 6 (b) is the second pulse signal of IN+ input. Figure 6 (c) in the figure is the pulse signal output by a single transformer. Figure 6 (d) in the figure is the pulse signal output by n transformers. When the turns ratio is 1, during the excitation operation, when IN+ and IN- input low-voltage control signals (such as 3.3V or 5V square wave signals), each transformer of the transmitting unit 1 will output a pulse signal of 2×V1, where V1 is the voltage of the DC low-voltage power supply DC. The transformers T1~Tn connected in series will output a high-voltage pulse excitation signal of 2×n×V1 to excite the array element 2 to work.

[0070] The transmitting unit 1 of this embodiment realizes high-voltage pulse transmission by connecting a single-ended transformer in series, so as to increase the excitation voltage. The transmitting unit 1 overcomes the large size and the interference of the switching ripple of the high-voltage power supply when boosting the voltage on the rear-end weak signal amplification and transmission circuit caused by the conventional high-voltage power amplifier circuit used in the fully single-ended or fully differential transmitting unit due to the need for an independent high-voltage power supply and a complex signal amplification and transmission circuit. In addition, the transmitting unit 1 is a fully differential floating output without interference from the external earth, which overcomes the interference of the common-mode noise of the single-ended output of the conventional high-voltage power amplifier circuit, and realizes high-voltage transmission and high common-mode rejection ratio in a small volume. Since the transmitting unit 1 uses a transformer with a small turns ratio, its coil inductance is small and can output high-frequency pulse signals. However, if a single transformer with a high turns ratio is used for boosting output, due to the large number of turns and large coil inductance, only low-frequency pulse signals can be output, generally only up to the kilohertz level, and it is difficult to output ultrasonic megahertz level.

[0071] In this embodiment, the structure of each receiving unit 3 in the receiving unit array is consistent. Figure 5 As shown, the receiving unit 3 includes a balance compensation circuit, a clamping circuit module, an isolation circuit, a filtering compensation amplifier circuit and an amplifier circuit which are connected in sequence.

[0072] The balance compensation circuit includes a capacitor C1 and an inductor of a coil in the array element 2 . A first end of the capacitor C1 is connected to the in-phase end of the array element 2 , and a second end of the capacitor C1 is connected to the in-phase end of the array element 2 .

[0073] The clamping circuit module includes a first clamping circuit and a second clamping circuit, the first clamping circuit is connected to the first end of the capacitor C1, and the second clamping circuit is connected to the second end of the capacitor C1. The first clamping circuit includes a first resistor R1 and a first diode group D1, the first diode group D1 includes a first diode and a second diode, the first end of the first resistor R1 is connected to the first end of the capacitor C1, the second end of the first resistor R1 is respectively connected to the anode of the first diode and the cathode of the second diode, and the cathode of the first diode is connected to the anode of the second diode. The second clamping circuit includes a second resistor R2 and a second diode group D2, the second diode group D2 includes a third diode and a fourth diode, the first end of the second resistor R2 is connected to the second end of the capacitor C1, the second end of the second resistor R2 is respectively connected to the anode of the third diode and the cathode of the fourth diode, and the cathode of the third diode is connected to the anode of the fourth diode.

[0074] The isolation circuit includes a first buffer U1 and a second buffer U2. The first input end of the first buffer U1 is connected to the output end of the first clamp circuit, that is, the connection end of the second end of the first resistor R1 and the first diode group D1, and the second input end of the first buffer U1 is connected to the output end of the first buffer U1. The first input end of the second buffer U2 is connected to the output end of the second clamp circuit, that is, the connection end of the second end of the second resistor R2 and the second diode group D2, and the second input end of the second buffer U2 is connected to the output end of the second buffer U2.

[0075] The filtering compensation amplifier circuit includes a differential filter, an inductor, a first amplifier and a second amplifier. The first input end of the differential filter is connected to the output end of the first buffer, the second input end of the differential filter is connected to the output end of the second buffer, the first end of the inductor is respectively connected to the first output end of the differential filter and the input end of the first amplifier, and the second end of the inductor is respectively connected to the second output end of the differential filter and the input end of the second amplifier.

[0076] In this embodiment, there may be multiple filter compensation amplifier circuits. When there are two filter compensation amplifier circuits, at this time, the differential filter of the first filter compensation amplifier circuit is recorded as the first differential filter, the inductor is recorded as the first inductor, the first amplifier is recorded as the first amplifier, and the second amplifier is recorded as the second amplifier. The differential filter of the second filter compensation amplifier circuit is recorded as the second differential filter, the inductor is recorded as the second inductor, the first amplifier is recorded as the third amplifier, and the second amplifier is recorded as the fourth amplifier. Then, the first filter compensation amplifier circuit includes a first differential filter U3, a first inductor L1, a first amplifier U4 and a second amplifier U5. The first input end of the first differential filter U3 is connected to the output end of the first buffer U1, and the second input end of the first differential filter U3 is connected to the output end of the second buffer U2. The first end of the first inductor L1 is respectively connected to the first output end of the first differential filter U3 and the input end of the first amplifier U4, and the second end of the first inductor L1 is respectively connected to the second output end of the first differential filter U3 and the input end of the second amplifier U5. The second filtering compensation amplifier circuit includes a second differential filter U6, a second inductor L2, a third amplifier U7 and a fourth amplifier U8. The first input end of the second differential filter U6 is connected to the output end of the first amplifier U4, the second input end of the second differential filter U6 is connected to the output end of the second amplifier U5, the first end of the second inductor L2 is respectively connected to the first output end of the second differential filter U6 and the input end of the third amplifier U7, and the second end of the second inductor L2 is respectively connected to the second output end of the second differential filter U6 and the input end of the fourth amplifier U8.

[0077] The amplification circuit includes a differential amplifier U9. When there is one filtering and compensating amplifier circuit, the first input terminal of the differential amplifier U9 is connected to the output terminal of the first amplifier U4, and the second input terminal of the differential amplifier U9 is connected to the output terminal of the second amplifier U5; when there are two filtering and compensating amplifier circuits, the first input terminal of the differential amplifier U9 is connected to the output terminal of the third amplifier U7, and the second input terminal of the differential amplifier U9 is connected to the output terminal of the fourth amplifier U8.

[0078] When there are two filter compensation amplifier circuits, such as Figure 5As shown, the in-phase end and the inverting end of the array element 2 are respectively connected to the two ends of the capacitor C1, the inductance of the coil of the array element 2 and the capacitor C1 form a balanced compensation circuit, the output signal of the in-phase end of the array element 2 passes through the clamping circuit composed of the resistor R1 and the diode group D1, and then enters the buffer U1, the output signal of the inverting end of the array element 2 passes through the clamping circuit composed of the resistor R2 and the diode group D2, and then enters the buffer U2, the buffer U1 and the buffer U2 play an isolation role, the output signal of the buffer U1 and the output signal of the buffer U2 are filtered by the differential filter U3 to achieve the initial signal filtering, filter out some strong interference noise, and differential The output signal of the filter U3 is phase-compensated by the inductor L1, and then the in-phase signal is amplified by the amplifier U4, and the anti-phase signal is amplified by the amplifier U5. The output signal of the amplifier U4 and the output signal of the amplifier U5 are filtered again by the differential filter U6. The output signal of the differential filter U6 is phase-compensated by the inductor L2, and then the in-phase signal is amplified again by the amplifier U7, and the anti-phase signal is amplified again by the amplifier U8. The output signal of the amplifier U7 and the output signal of the amplifier U8 are amplified by the differential amplifier U9 and input into the analog-to-digital converter 6.

[0079] The receiving unit 3 of this embodiment adopts a single-ended buffer followed by a differential back-end addition amplifier, and adopts a floating ground symmetrical structure to achieve differential amplification of the signal of the single-ended electromagnetic ultrasonic sensor without the need for a complex differential electromagnetic ultrasonic sensor with a ground pin. Compared with the fully differential type, the sensor design is simplified, and compared with the fully single-ended type, amplification of high signal-to-noise ratio signals is achieved.

[0080] The following further compares the performance of the full single-ended type, the full differential type, and the partial single-ended and partial differential type of this embodiment. Figure 7 and Figure 8 As shown in FIG. 1 , it is a schematic diagram of an electromagnetic ultrasonic signal obtained by a full single-ended method (i.e., after amplification using a single-ended electromagnetic ultrasonic sensor and a single-ended receiving unit). Obviously, the electromagnetic ultrasonic signal contains random crosstalk, which affects the detection. Fig. 9 and Fig.10 As shown in FIG. 1 , it is a schematic diagram of an electromagnetic ultrasonic signal obtained by a full differential method (i.e., after amplification using a differential electromagnetic ultrasonic sensor and a differential receiving unit). Obviously, there is no random crosstalk in the electromagnetic ultrasonic signal, and the signal-to-noise ratio is relatively high. Fig.11 and Figure 8 As shown, it is a schematic diagram of the electromagnetic ultrasonic signal obtained by the partial single-ended and partial differential type (i.e., after amplification by using a single-ended electromagnetic ultrasonic sensor and a differential receiving unit) of this embodiment. Obviously, there is no random crosstalk in the electromagnetic ultrasonic signal, and the signal basic background noise is relatively Fig. 9 Higher, higher signal-to-noise ratio and better detection effect.

[0081] This embodiment provides a differential high-power excitation and high signal-to-noise ratio reception electromagnetic ultrasonic phased array device, which can achieve high-power excitation and high signal-to-noise ratio reception, realize high-power ultrasonic excitation in a small volume, and improve the signal-to-noise ratio of the received signal, and use a single-ended coil to achieve differential transmission and differential reception, which reduces the difficulty of sensor manufacturing, so that electromagnetic ultrasonic detection technology is moving out of the laboratory and towards engineering detection applications.

[0082] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device, characterized in that: The differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device comprises: a transmitting unit array, a sensor array and a receiving unit array; The transmitting unit array includes a plurality of transmitting units, wherein the transmitting units are floating differential transmitting units, and the transmitting units include a plurality of transformers connected in series; The sensor array includes a plurality of array elements, wherein the array elements are single-ended electromagnetic ultrasonic sensors; A receiving unit array includes a plurality of receiving units, wherein the receiving units are floating differential receiving units; The transmitting unit, the array element and the receiving unit correspond to each other one by one; the transmitting unit is connected to the array element, and the transmitting unit is used to transmit a pulse excitation signal to stimulate the array element to work; the array element is used to complete the electro-magnetic-acoustic transduction, generate ultrasonic waves to detect the components under test, and convert the detection echoes into detection electrical signals; the array element is connected to the receiving unit, and the receiving unit is used to perform signal conditioning on the detection electrical signals to obtain conditioned electrical signals; The first end of the primary coil of each transformer is connected to a first switch tube, the middle tap of each transformer is connected to a DC power supply, the second end of the primary coil of each transformer is connected to a second switch tube, all the first switch tubes are connected to the negative input end of the transmitting unit, and all the second switch tubes are connected to the positive input end of the transmitting unit, the negative input end is used to input a first pulse signal, and the positive input end is used to input a second pulse signal, and the first pulse signal and the second pulse signal have the same amplitude and opposite polarity; The first end of the secondary coil of the first transformer is connected to the positive output end of the transmitting unit, the first end of the secondary coil of the i-th transformer is connected to the second end of the secondary coil of the i-1-th transformer, i=2, 3, ..., n, n is the total number of transformers, and the second end of the secondary coil of the n-th transformer is connected to the negative output end of the transmitting unit; The positive output terminal of the transmitting unit is connected to the in-phase terminal of the array element, and the negative output terminal of the transmitting unit is connected to the inverting terminal of the array element; The transmitting unit further includes: a first impedance matching circuit and a second impedance matching circuit; The first impedance matching circuit is located between the first end of the secondary coil of the first transformer and the positive output terminal of the transmitting unit, the first end of the first impedance matching circuit is connected to the first end of the secondary coil of the first transformer, and the second end of the first impedance matching circuit is connected to the positive output terminal of the transmitting unit; The second impedance matching circuit is located between the second end of the secondary coil of the nth transformer and the negative output end of the transmitting unit, the first end of the second impedance matching circuit is connected to the second end of the secondary coil of the nth transformer, and the second end of the second impedance matching circuit is connected to the negative output end of the transmitting unit.

2. The differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device according to claim 1, characterized in that: The receiving unit comprises a balance compensation circuit, a clamping circuit module, an isolation circuit, a filtering compensation amplifying circuit and an amplifying circuit which are connected in sequence.

3. The differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device according to claim 2, characterized in that: The balance compensation circuit includes a capacitor and an inductor of a coil in an array element, a first end of the capacitor is connected to the in-phase end of the array element, and a second end of the capacitor is connected to the inverting end of the array element; The clamping circuit module includes a first clamping circuit and a second clamping circuit, the first clamping circuit is connected to the first end of the capacitor, and the second clamping circuit is connected to the second end of the capacitor; The isolation circuit includes a first buffer and a second buffer; the first input end of the first buffer is connected to the output end of the first clamp circuit, and the second input end of the first buffer is connected to the output end of the first buffer; the first input end of the second buffer is connected to the output end of the second clamp circuit, and the second input end of the second buffer is connected to the output end of the second buffer; The filter compensation amplifier circuit includes a differential filter, an inductor, a first amplifier and a second amplifier; the first input end of the differential filter is connected to the output end of the first buffer, and the second input end of the differential filter is connected to the output end of the second buffer; the first end of the inductor is respectively connected to the first output end of the differential filter and the input end of the first amplifier; the second end of the inductor is respectively connected to the second output end of the differential filter and the input end of the second amplifier; The amplifying circuit comprises a differential amplifier; a first input end of the differential amplifier is connected to an output end of the first amplifier, and a second input end of the differential amplifier is connected to an output end of the second amplifier.

4. The differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device according to claim 3, characterized in that: The first clamping circuit includes a first resistor and a first diode group, the first diode group includes a first diode and a second diode, the first end of the first resistor is connected to the first end of the capacitor, the second end of the first resistor is respectively connected to the anode of the first diode and the cathode of the second diode, and the cathode of the first diode is connected to the anode of the second diode; The second clamping circuit includes a second resistor and a second diode group, the second diode group includes a third diode and a fourth diode, the first end of the second resistor is connected to the second end of the capacitor, the second end of the second resistor is respectively connected to the anode of the third diode and the cathode of the fourth diode, and the cathode of the third diode is connected to the anode of the fourth diode; There are multiple filtering compensation amplifier circuits.

5. The differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device according to claim 1, characterized in that: The differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device also includes: The phase-controlled module is connected to the transmitting unit array and is used to excite several transmitting units in the transmitting unit array according to preset working parameters and delay rules, so that the transmitting units emit pulse excitation signals; the working parameters include the amplitude and frequency of the excitation waveform, and the delay rule includes the delay sequence and delay time.

6. The differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device according to claim 5, characterized in that: The differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device also includes: The analog-to-digital converter array includes a plurality of analog-to-digital converters, and the analog-to-digital converters correspond to the receiving units one by one; the analog-to-digital converters are connected to the receiving units, and the analog-to-digital converters are used to perform analog-to-digital conversion on the conditioned electrical signals output by the receiving units to obtain digital electrical signals.

7. The differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device according to claim 6, characterized in that: The differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device also includes: The data processing module is connected to the analog-to-digital converter array and is used to perform imaging based on all digital electrical signals obtained by the analog-to-digital converter array to obtain the detection results of the tested components.

8. The differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device according to claim 7, characterized in that: The differential high-power excitation and high signal-to-noise ratio receiving electromagnetic ultrasonic phased array device also includes: The main control module is connected to the phase control module and the data processing module respectively, and is used to send working parameters and delay rules to the phase control module, and receive detection results obtained by the data processing module; The display module is connected to the main control module and is used to display the test results and realize human-computer interaction.

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