CN106989702B - Pulse excitation type electromagnetic ultrasonic detector - Google Patents

Abstract

The invention discloses a pulse excitation type electromagnetic ultrasonic detector. Wherein, this detector includes: a programmable ASIC device generating a plurality of signals, wherein the plurality of signals includes a plurality of transmit control signals and a charge control signal; a voltage conversion circuit that converts a low voltage signal into a high voltage signal; a transmitting circuit for generating a high-voltage and high-current excitation signal; the electromagnetic ultrasonic sensor generates an ultrasonic signal according to the excitation signal and transmits the received ultrasonic echo signal to the receiving signal conditioning and sampling circuit; and the receiving signal conditioning and sampling circuit is used for processing and analog-to-digital converting the receiving signal of the electromagnetic ultrasonic sensor and writing waveform data points into a storage unit in the programmable ASIC device. The invention solves the technical problem that the traditional electromagnetic ultrasonic thickness gauge can not emit high-voltage and high-current under the conditions of small volume, low power consumption and power supply of a battery.

Description

Pulse excitation electromagnetic ultrasonic detector

Technical field

The present invention relates to the field of ultrasonic detection, and specifically to a pulse excitation electromagnetic ultrasonic detector.

Background technique

Ultrasonic testing technology is widely used in thickness measurement and flaw detection of metal equipment. Compared with traditional piezoelectric ultrasonic testing technology, electromagnetic ultrasonic testing does not require polishing of the surface when testing metal equipment, which can save testing time and costs. It is suitable for occasions with anti-rust paint and where grinding is not allowed; electromagnetic ultrasonic testing The detection does not require the use of coupling agent, which can avoid the problem of poor repeatability of detection results caused by the volatilization or uneven application of the coupling agent. Since the electromagnetic ultrasonic sensor can achieve non-contact detection, it is especially suitable for high temperature detection occasions. In addition, since electromagnetic ultrasonic sensors are relatively cheaper and easier to design and manufacture than piezoelectric sensors, they are a technology that urgently needs to be developed in the field of non-destructive testing of metal equipment.

However, existing electromagnetic ultrasonic testing instruments are difficult to emit high-voltage and high-current excitation signals under low power consumption and low-voltage battery power supply conditions, which limits the application of electromagnetic ultrasonic testing technology in portable, online monitoring, multi-channel array testing and other occasions. Applications.

In response to the above problems, no effective solution has yet been proposed.

Contents of the invention

Embodiments of the present invention provide a pulse excitation electromagnetic ultrasonic detector to at least solve the problem that existing electromagnetic ultrasonic thickness measurement instruments cannot emit high-voltage and large-current excitation signals under the conditions of small size, low power consumption, and low-voltage battery power supply. technical problem.

According to an aspect of an embodiment of the present invention, a pulse excitation electromagnetic ultrasonic detector is provided, including: a programmable ASIC device for generating multiple channels of signals, wherein the multiple channels of signals include four channels of emission control signals and charging control signal; a voltage conversion circuit, connected to the programmable ASIC device, for converting a low voltage signal into a high voltage signal when receiving the charging control signal; a transmitting circuit, connected to the programmable ASIC device and the The voltage conversion circuit is connected and is used to generate a high-voltage and high-current excitation signal according to the emission control signal and the high-voltage signal; the electromagnetic ultrasonic sensor is connected to the emission circuit and is used to generate an excitation signal according to the excitation signal. Ultrasonic signals, and receive echo signals, wherein the echo signals are reflection signals when the ultrasonic signals encounter structural defects and boundaries to be inspected during propagation; receive signal conditioning and sampling circuits, and the electromagnetic ultrasonic The sensors are connected and used to process and sample the ultrasonic echo signals to obtain waveform data points and write them into the storage unit inside the programmable ASIC device.

Further, the voltage conversion circuit includes: a low-voltage power supply for providing a low-voltage signal; a charging control circuit connected to the programmable ASIC device and the low-voltage power supply. The charging control circuit receives the charging signal. When controlling the signal, the low-voltage power supply is controlled to charge the high-voltage capacitor; the high-voltage capacitor is connected to the charging control circuit and the transmitting circuit, and is charged to a high voltage through the low-voltage power supply to provide the transmitting circuit with the high voltage signal.

Further, four high-speed isolation circuits are connected to the programmable ASIC device, wherein the four high-speed isolation circuits output four analog input signals according to the four transmission control signals, and control the four transmission The control signal is isolated from the four analog input signals. The four analog input signals include a first group of analog input signals and a second group of analog input signals. The first group of analog input signals are separated from the second group of analog input signals. The input signals respectively include two analog input signals with the same polarity. The first group of analog input signals and the second group of analog input signals have opposite polarities; four voltage and current amplification circuits are isolated from the four high-speed The circuit is connected and used to amplify the first group of analog input signals and the second group of analog input signals to obtain the first group of driving signals and the second group of driving signals; the full-bridge high-voltage and high-current switching circuit is connected to the first group of analog input signals and the second group of analog input signals. The four-way voltage and current amplifier circuit is connected to the voltage conversion circuit, wherein the voltage conversion circuit provides the high voltage signal for the full-bridge high-voltage and high-current switching circuit, and the full-bridge high-voltage and high-current switching circuit is based on The first group of driving signals and the second group of driving signals adjust the operating state, and the operating state includes on or off; a high-voltage transformer conversion circuit is connected to the full-bridge high-voltage and high-current switching circuit, and is used according to the The excitation signal is generated by turning on or off the full-bridge high-voltage and high-current switching circuit.

Further, the full-bridge high-voltage and high-current switching circuit includes: a first switch group connected to the four-way voltage and current amplification circuit. When the voltage of the first group of driving signals meets the first preset voltage, the The first switch group is turned on; the second switch group is connected to the four-way voltage and current amplifier circuit. When the voltage of the second group of driving signals meets the second preset voltage, the second switch group is turned on. Pass.

Further, the first switch group includes a left arm high-end switch and a right arm low-end switch. When the voltage of the first group of driving signals meets the first preset voltage, the left arm high-end switch and the right arm low-end switch The end switch is turned on; the second switch group includes a left arm low-end switch and a right arm high-end switch. When the voltage of the second group of driving signals meets the second preset voltage, the left arm low-end switch and the right arm high-end switch are The high-end switch of the right arm is turned on.

Further, the high-voltage transformer conversion circuit includes: a tuning circuit connected to the left arm high-side switch and the left arm low-side switch; a high-voltage transformer, the first end of the primary side of the high-voltage transformer is connected to the tuning circuit. connection, the second end of the primary side of the high-voltage transformer is connected to the high-end switch of the right arm and the low-end switch of the right arm, the first end of the secondary side of the high-voltage transformer is grounded, and the secondary end of the high-voltage transformer is connected to the ground. The second end of the side is connected to the electromagnetic ultrasonic sensor.

Further, the detector further includes: a processor unit connected to the programmable ASIC device for receiving parameters, wherein the programmable ASIC device generates the multi-channel signal according to the parameters; waveform data a storage unit connected to the processor unit, wherein the processor unit reads the waveform data points from the storage unit inside the programmable ASIC device and stores the waveform data points in the waveform data in the storage unit.

Further, the receiving signal conditioning and sampling circuit includes: a receiving signal conditioning circuit, connected to the electromagnetic ultrasonic sensor, for processing the echo signal to obtain a processed echo signal; an analog-to-digital conversion circuit. , connected to the received signal conditioning circuit, used to sample the processed echo signal to obtain the waveform data points.

Further, the received signal conditioning circuit includes: a limiting circuit connected to the electromagnetic ultrasonic sensor; a low-noise preamplifier circuit connected to the limiting circuit; a fixed gain amplifier circuit connected to the low-noise A preamplifier circuit is connected; a bandpass filter circuit is connected to the fixed gain amplification circuit; a first-level program-controlled amplification circuit is connected to the band-pass filter circuit; a second-level programmable amplification circuit is connected to the third-level programmable amplification circuit. The first-level program-controlled amplification circuit is connected; the low-pass filter circuit is connected with the second-level program-controlled amplification circuit.

Further, the multi-channel signal includes a gain setting signal and a frequency selection signal, and the received signal conditioning and sampling circuit includes: a gain voltage setting circuit, together with the programmable ASIC device, the first-level program-controlled amplification circuit and The second-level program-controlled amplification circuit is connected and used to output a voltage signal according to the gain setting signal. The voltage signal is used to set the gains of the first-level program-controlled amplification circuit and the second-level program-controlled amplification circuit. ; Cutoff frequency selection circuit, connected to the programmable ASIC device and the bandpass filter circuit, for setting the cutoff frequency of the bandpass filter circuit according to the frequency selection signal.

In the embodiment of the present invention, a programmable ASIC device is used to generate multiple signals, wherein the multiple signals include multiple emission control signals and charging control signals; a voltage conversion circuit is connected to the programmable ASIC device. Connection, used to convert a low voltage signal into a high voltage signal when receiving the charging control signal; a transmitting circuit, connected to the programmable ASIC device and the voltage conversion circuit, used to convert the low voltage signal into a high voltage signal according to the transmit control signal and the high voltage signal to generate a high voltage and high current excitation signal; an electromagnetic ultrasonic sensor, connected to the transmitting circuit, for generating an ultrasonic signal according to the excitation signal and receiving the echo signal; receiving signal conditioning and A sampling circuit is connected to the electromagnetic ultrasonic sensor and the programmable ASIC device, and is used to process and sample the reflected signal, obtain waveform data points and write them into the storage unit inside the programmable ASIC device. Compared with the existing technology, the pulse excitation electromagnetic ultrasonic detector provided by the present invention achieves the purpose of emitting high voltage and high current excitation signals under the conditions of small size, low power consumption and low voltage power supply, thereby achieving reduced The technical effect of pulse excitation electromagnetic ultrasonic detector power consumption solves the technical problem that existing electromagnetic ultrasonic thickness measurement instruments cannot emit high voltage and large current under the conditions of small size, low power consumption, and low-voltage battery power supply.

Description of the drawings

The drawings described here are used to provide a further understanding of the present invention and constitute a part of this application. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the attached picture:

Figure 1 is a structural diagram of an optional pulse excitation electromagnetic ultrasonic detector according to an embodiment of the present invention;

Figure 2 is a work flow chart of an optional pulse excitation electromagnetic ultrasonic detector according to an embodiment of the present invention.

Detailed ways

In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only These are some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts should fall within the scope of protection of the present invention.

It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances so that the embodiments of the invention described herein are capable of being practiced in sequences other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, e.g., a process, method, system, product, or apparatus that encompasses a series of steps or units and need not be limited to those explicitly listed. Those steps or elements may instead include other steps or elements not expressly listed or inherent to the process, method, product or apparatus.

According to an embodiment of the present invention, an embodiment of a pulse-excited electromagnetic ultrasonic detector is provided. The pulse-excited electromagnetic ultrasonic detector can be used in fields such as ultrasonic thickness measurement and ultrasonic flaw detection, and according to the detector, it can be easily Instruments and equipment such as ultrasonic thickness gauges and ultrasonic flaw detectors are derived.

Figure 1 is a structural diagram of a pulse excitation electromagnetic ultrasonic detector according to an embodiment of the present invention. As shown in Figure 1, the detector includes:

The programmable ASIC device 101 is used to generate multiple channels of signals, where the multiple channels of signals include up to four channels of emission control signals and charging control signals.

In the embodiment of the present invention, the programmable ASIC device can use FPGA or CPLD to realize its functions. Specifically, the programmable ASIC device is used to generate multiple control signals, including four emission control signals and charging control signals, where The programmed ASIC device generates four emission control signals according to the preset frequency according to the preset parameters. The generated emission control signals are digital signals. The four emission control signals include two emission control signals with the same polarity and two poles. The transmission control signal has the opposite characteristic, and the four transmission control signals are all square wave signals with a limited period.

The voltage conversion circuit 102 is connected to the programmable ASIC device and is used to convert the low voltage signal into a high voltage signal when receiving the charging control signal.

In the embodiment of the present invention, the voltage conversion circuit receives the charging control signal generated by the programmable ASIC device, and under the control of the charging control signal, converts the low voltage signal into a high voltage signal, wherein the converted high voltage signal is used for It supplies power to the full-bridge high-voltage and high-current switching circuit in the pulse-excited electromagnetic ultrasonic detector and generates high-voltage and high-current excitation signals.

The transmitting circuit 103 is connected to the programmable ASIC device and the voltage conversion circuit, and is used to generate a high voltage and high current excitation signal according to the transmitting control signal and the high voltage signal.

In the embodiment of the present invention, the transmitting circuit outputs a high-voltage and high-current excitation signal based on the four-channel transmitting control signals generated by the programmable ASIC device and the high-voltage signal provided by the voltage conversion circuit. Specifically, the programmable ASIC device first generates a charging control signal, and controls the voltage conversion circuit to convert the low voltage signal into a high voltage signal. Subsequently, the programmable ASIC device generates four transmission control signals, and the control transmission circuit outputs a device according to the high voltage signal. A high-voltage and high-current excitation signal with a fixed repetition frequency.

The electromagnetic ultrasonic sensor 104 is connected to the transmitting circuit and is used to generate an ultrasonic signal according to the excitation signal and receive an echo signal, where the echo signal is when the ultrasonic signal encounters structural defects and boundaries to be detected during propagation. reflected signal.

In the embodiment of the present invention, the electromagnetic ultrasonic sensor is driven by the high-voltage and high-current excitation signal output by the transmitting circuit to generate an ultrasonic signal. At the same time, the electromagnetic ultrasonic sensor is also used to receive the reflection signal of the ultrasonic signal from the boundary or internal defect of the object to be detected. The reflected signal is an ultrasonic echo signal, where the ultrasonic echo signal contains detection information of the object to be detected.

The receiving signal conditioning and sampling circuit 105 is connected to the electromagnetic ultrasonic sensor and the programmable ASIC device, and is used for processing and analog-to-digital conversion of the echo signal. The converted waveform data points are written into the storage unit inside the programmable ASIC device. Alternatively, the waveform data points written into the storage unit inside the programmable ASIC device can be stored in the waveform data storage unit. Optionally, the processor unit reads the waveform data points from the storage unit inside the programmable ASIC device, adds them to the data at the corresponding position in the waveform data storage unit, and rewrites the result into the corresponding position in the waveform data storage unit, and Send the average results to the waveform data output interface.

In the embodiment of the present invention, the signals received by the electromagnetic ultrasonic sensor include high-voltage and high-current excitation signals, ultrasonic echo signals, and interference signals. The received signal conditioning and sampling circuit is used to process the signals received by the electromagnetic ultrasonic sensor. Preferably, The receiving signal conditioning and sampling circuit can attenuate the high-voltage and high-current excitation signal to a large extent, amplify the amplitude of the ultrasonic echo signal by a large factor, suppress the interference signal through filtering, and then process the received signal. The signal undergoes analog-to-digital conversion, converts the processed reflected signal into a digital signal, obtains waveform data points, and writes the waveform data points into the programmable ASIC device. Optionally, when the programmable ASIC device is an FPGA, the waveform data points sampled by the receiving signal conditioning and sampling circuit are written into the storage unit inside the FPGA until the receiving circuit completes the collection of a set of signals.

In the embodiment of the present invention, a programmable ASIC device is used to generate multiple signals, where the multiple signals include four emission control signals and charging control signals; a voltage conversion circuit is connected to the programmable ASIC device to generate When receiving the charging control signal, the low-voltage signal is converted into a high-voltage signal; the transmitting circuit is connected to the programmable ASIC device and the voltage conversion circuit, and is used to generate a high-voltage and high-current excitation signal based on the transmitting control signal and the high-voltage signal. ; The electromagnetic ultrasonic sensor is connected to the transmitting circuit and is used to generate an ultrasonic signal based on the excitation signal and receive the reflected signal of the ultrasonic signal; the receiving signal conditioning and sampling circuit is connected to the electromagnetic ultrasonic sensor and the programmable ASIC device for The reflected signal is processed and sampled, and the waveform data points are obtained and written into the programmable ASIC device. Compared with the existing technology, the pulse excitation electromagnetic ultrasonic detector provided by the present invention achieves the purpose of emitting high voltage and high current excitation signals under the conditions of small size, low power consumption and low voltage power supply, thereby achieving reduced The technical effect of pulse excitation electromagnetic ultrasonic detector power consumption solves the technical problem that existing electromagnetic ultrasonic thickness measurement instruments cannot emit high voltage and large current under the conditions of small size, low power consumption, and low-voltage battery power supply.

Optionally, the voltage conversion circuit 102 includes: a low-voltage power supply 1021, used to provide a low-voltage signal; a charging control circuit 1022, connected to the programmable ASIC device and the low-voltage power supply. When receiving the charging control signal, the charging control circuit controls the low-voltage The power supply charges the high-voltage capacitor; the high-voltage capacitor 1023 is connected to the charging control circuit and the transmitting circuit, and is charged to high voltage by the low-voltage power supply to provide a high-voltage signal to the transmitting circuit.

As an optional implementation of the embodiment of the present invention, the voltage conversion circuit includes a low-voltage power supply, a charging control circuit and a high-voltage capacitor, wherein the charging control circuit is used to receive the charging control signal generated by the programmable ASIC device, and after receiving After the charging control signal, the low-voltage power supply is controlled to charge the high-voltage capacitor, and the high-voltage capacitor is charged to high voltage, thereby converting the low-voltage signal to a high-voltage signal, thereby providing a high-voltage signal to the transmitter circuit. Optionally, a low-voltage battery can be used as the low-voltage power supply, and a high-voltage aluminum electrolytic capacitor can be used as the high-voltage capacitor to achieve portability and miniaturization of the pulse-excited electromagnetic ultrasonic detector.

Optionally, the transmit circuit 103 includes: four high-speed isolation circuits 1031, connected to the programmable ASIC device, wherein the four high-speed isolation circuits output four analog input signals according to the four transmit control signals, and control the four transmit The signal is isolated from four analog input signals. The four analog input signals include a first group of analog input signals and a second group of analog input signals. The first group of analog input signals and the second group of analog input signals respectively include analog input signals with the same polarity. Input signals, the first group of analog input signals and the second group of analog input signals have opposite polarities; four voltage and current amplification circuits 1032 are connected to four high-speed isolation circuits for converting the first group of analog input signals The signal and the second set of analog input signals are amplified to obtain the first set of driving signals and the second set of driving signals; the full-bridge high-voltage and high-current switching circuit 1033 is connected to the multi-channel voltage and current amplification circuit and the voltage conversion circuit, in which the voltage The conversion circuit provides high voltage signals for the full-bridge high-voltage and high-current switching circuit. The full-bridge high-voltage and high-current switching circuit adjusts the operating state according to the first set of drive signals and the second set of drive signals. The operating state includes on or off; high-voltage transformer conversion circuit 1034 is connected to the full-bridge high-voltage and high-current switching circuit, and is used to generate an excitation signal based on the conduction or cut-off of the full-bridge high-voltage and high-current switching circuit.

As an optional implementation of the embodiment of the present invention, the transmitting circuit includes four high-speed isolation circuits, four voltage and current amplification circuits, a full-bridge high-voltage and high-current amplification circuit and a high-voltage transformer conversion circuit, wherein the four-way high-speed isolation circuit Receive four emission control signals generated by the programmable ASIC device. Each high-speed isolation circuit generates an analog input signal based on one emission control signal, thereby obtaining four analog input signals, and the four analog input signals include the first group of analog input signals. and the second group of analog input signals. The first group of analog input signals includes two signals with the same polarity. The second group of analog input signals includes two signals with the same polarity. The polarity of the first group of analog input signals is the same as that of the second group of analog input signals. The second set of analog input signals has opposite polarity. The four-way high-speed isolation circuit is also used to isolate the emission control signal from the subsequent analog circuit; the four-way voltage and current amplification circuit amplifies the first set of analog input signals and the second set of analog input signals to obtain the first set of driving signals and the third set of analog input signals. Two sets of drive signals. The first set of drive signals includes two drive signals with the same polarity. The second set of drive signals includes two drive signals with the same polarity. The polarity of the first set of drive signals is the same as that of the second set of drive signals. The polarity is opposite; the full-bridge high-voltage and high-current switching circuit adjusts the operating state to off or on according to the first set of driving signals and the second set of driving signals, and the high-voltage transformer conversion circuit adjusts the operating state to off according to the operating state of the full-bridge high-voltage and high-current switching circuit. Or turn on to generate an excitation signal.

Optionally, the full-bridge high-voltage and high-current switching circuit includes: a first switch group connected to four voltage and current amplifier circuits. When the voltage of the first group of driving signals meets the first preset voltage, the first switch group is turned on. ; The second switch group is connected to the four voltage and current amplifier circuits. When the voltage of the second group of driving signals meets the second preset voltage, the second switch group is turned on.

As an optional implementation of the embodiment of the present invention, the full-bridge high-voltage and high-current switch includes a first switch group and a second switch group. The first switch group adjusts the operating state to be off or on according to the first group of driving signals. The second group of switches adjusts the operating state to be off or on according to the second drive signal. When the voltage of the first group of drive signals meets the first preset voltage, the first switch group is turned on. When the second group of drive signals When the voltage meets the second pre-voltage, the second switch group is turned on, and the first group of driving signals and the second group of driving signals have opposite polarities. When the first switch group is turned on, the second switch group is turned off. When the second switch group When it is turned on, the first switch group is turned off. When no signal is emitted, the first switch group and the second switch group are in the cutoff state at the same time.

Optionally, the first switch group includes a left arm high-end switch and a right arm low-end switch. When the voltage of the first group of driving signals meets the first preset voltage, the left arm high-end switch and the right arm low-end switch are turned on; second The switch group includes a left arm low-end switch and a right arm high-end switch. When the voltage of the second group of driving signals meets the second preset voltage, the left arm low-end switch and the right arm high-end switch are turned on. When no signal is emitted, the first The switch group and the second switch group are in the off state at the same time.

As an optional implementation of the embodiment of the present invention, the first switch group includes a left arm high-end switch and a right arm low-end switch, and the second switch group includes a left arm low-end switch and a right arm high-end switch. In the first group When the voltage of the drive signal meets the first preset voltage, the high-end switch of the left arm and the low-end switch of the right arm are turned on at the same time. When the second drive signal meets the second preset voltage, the low-end switch of the left arm and the high-end switch of the right arm are turned on at the same time. Because the polarity of the first group of drive signals and the second group of drive signals are opposite, when the left arm high-end switch and the right arm low-end switch are on, the left arm low-end switch and the right arm high-end switch are off, and when the left arm low-end switch is on, When the switch and the high-end switch of the right arm are turned on, the high-end switch of the left arm and the low-end switch of the right arm are turned off. When no signal is emitted, the first switch group and the second switch group are in a cut-off state at the same time.

Optionally, the high-voltage transformer conversion circuit includes: a tuning circuit connected to the contacts of the left arm high-side switch and the left arm low-side switch; a high-voltage transformer, the first end of the primary side of the high-voltage transformer is connected to the tuning circuit, and the high-voltage transformer The second end of the primary side is connected to the contact point of the right arm high-end switch and the right arm low-end switch, the first end of the secondary side of the high-voltage transformer is grounded, and the second end of the secondary side of the high-voltage transformer is connected to the electromagnetic ultrasonic sensor.

As an optional implementation of the embodiment of the present invention, the high-voltage transformer conversion circuit includes a tuning circuit and a high-voltage transformer, wherein one end of the primary winding of the high-voltage transformer is connected to the low end of the left arm of the full-bridge high-voltage and high-current switching circuit through the tuning circuit. The contact point of the switch and the high-end switch of the left arm. The other end of the primary winding of the high-voltage transformer is connected to the contact point of the low-end switch of the right arm and the high-end switch of the right arm of the full-bridge high-voltage and high-current switching circuit. One end of the secondary winding of the high-voltage transformer is grounded, and the other end Connected to the electromagnetic ultrasonic sensor, the high-voltage transformer provides a high-voltage and high-current excitation signal to the electromagnetic ultrasonic sensor according to the on or off state of the full-bridge high-voltage and high-current switching circuit.

Optionally, the received signal conditioning and sampling circuit 105 includes: a received signal conditioning circuit 1051, connected to the electromagnetic ultrasonic sensor, for processing the echo signal to obtain a processed echo signal; an analog-to-digital conversion circuit 1052, and The receiving signal conditioning circuit is connected and used to sample the processed echo signal to obtain waveform data points.

As an optional implementation of the embodiment of the present invention, the received signal conditioning and sampling circuit includes a received signal conditioning circuit and an analog-to-digital conversion circuit, wherein the received signal conditioning circuit is used to at least limit the received signal of the electromagnetic ultrasonic sensor. , amplification and filtering to obtain the processed ultrasonic echo signal, and the analog-to-digital conversion circuit samples the processed ultrasonic echo signal to obtain waveform data points.

Optionally, the received signal conditioning circuit 1051 includes: a limiting circuit 10511, connected to the electromagnetic ultrasonic sensor; a low-noise preamplifier circuit 10512, connected to the limiting circuit; a fixed gain amplifying circuit 10513, connected to the low-noise preamplifier The band-pass filter circuit 10514 is connected to the fixed-gain amplification circuit; the first-level program-controlled amplification circuit 10515 is connected to the band-pass filter circuit; the second-level program-controlled amplification circuit 10516 is connected to the first-level program-controlled amplification circuit. Connection; low-pass filter circuit 10517, connected to the second-stage program-controlled amplifier circuit.

As an optional implementation of the embodiment of the present invention, the received signal conditioning circuit includes an amplitude limiting circuit, a low-noise preamplifier circuit, a fixed gain amplification circuit, a band-pass filter circuit, a first-stage program-controlled amplification circuit and a second-stage Programmable amplification circuit, in which an amplitude limiting circuit is used to attenuate the high-voltage and high-current signals in the received signal of the electromagnetic ultrasonic sensor at a larger amplitude, and the weak ultrasonic echo signal is amplified by a large factor, and a band-pass filter is used to eliminate interference The signal is suppressed, and a low-noise preamplifier circuit, a fixed-gain amplification circuit, a first-level programmable amplification circuit, and a second-level programmable amplification circuit are used to amplify the reflected signal respectively, and a low-pass filter is used to anti-alias the reflected signal.

Optionally, the multi-channel signal includes a gain setting signal and a frequency selection signal. The received signal conditioning and sampling circuit 105 includes: a gain voltage setting circuit 1053, and a programmable ASIC device, a first-level program-controlled amplification circuit and a second-level program-controlled amplification circuit. The circuit is connected and outputs two voltage signals according to the gain setting signal. The two voltage signals respectively set the gain of the first-level program-controlled amplification circuit and the second-level program-controlled amplification circuit; the cut-off frequency selection circuit 1054 is connected with the programmable ASIC device and the band. It is connected to the pass filter circuit and is used to set the cutoff frequency of the band pass filter circuit according to the frequency selection signal.

As an optional implementation of the embodiment of the present invention, the received signal conditioning and sampling circuit also includes a gain voltage setting circuit and a cutoff frequency selection circuit, wherein the gain voltage setting circuit is used to determine the first program-controlled amplifier circuit and the second-stage program-controlled amplifier circuit. The amplification factor of the amplifier circuit and the cutoff frequency selection circuit are used to determine the cutoff frequency of the bandpass filter. Specifically, the programmable ASIC device generates multiple control signals including gain setting signals and frequency selection signals. The gain voltage setting circuit is connected to the programmable ASIC device, and the value of its output voltage is adjusted according to the gain setting signal. The bandpass filter is connected to the output end of the gain voltage setting circuit, and the gain voltage setting circuit determines the first value through its output voltage. The amplification factor of the first-level programmable amplification circuit and the second-level programmable amplification circuit, optionally, in a preferred implementation of the embodiment of the present invention, the gain of the preamplifier is 20dB, and the gain of the fixed-gain amplification circuit is 20dB, Through the output voltage of the gain voltage setting circuit, the maximum gain of the first-stage program-controlled amplification circuit and the second-stage program-controlled amplification circuit are both set to 34dB, and their minimum gain is set to 4dB, thereby making the gain selection of the received signal conditioning and sampling circuit The range is 48dB-108dB. The cutoff frequency selection circuit is connected to the ASIC device, and the cutoff frequency selection circuit selects the cutoff frequency of the bandpass filter according to the frequency selection signal.

Optionally, the detector also includes: a processor unit 106, connected to the programmable ASIC device, for receiving parameters, and controlling the programmable ASIC device to generate multiple signals according to the parameters; a waveform data storage unit 107, and the processor unit are connected, wherein the processor unit reads the waveform data points from the programmable ASIC device and stores the waveform data points in the waveform data storage unit.

As an optional implementation of the embodiment of the present invention, the pulse excitation electromagnetic ultrasonic detector provided by the present invention also includes a processor unit and a waveform data storage unit. The processor unit can use ARM or DSP to realize its functions. , specifically, the processor unit is connected to the programmable ASIC device. The processor unit includes a parameter input interface, receives parameters through the parameter input interface, and causes the programmable ASIC device to generate multiple control signals according to the parameters. Optionally, when When the programmable ASIC device is an FPGA, the parameters received by the processor unit through the parameter input interface include: excitation frequency and gain. The processor sets the above parameters into the FPGA's excitation frequency register, gain register and adoption frequency register respectively. The FPGA adjusts the parameters according to the corresponding The parameter values in the register generate corresponding control signals. For example: FPGA generates four transmission control signals of corresponding frequencies according to the excitation frequency in the excitation frequency register. At the same time, the signal is selected according to the cut-off frequency to determine the cut-off frequency of the band-pass filter; according to The value of the gain register generates a gain setting signal, thereby determining the gains of the first-stage program-controlled amplifier circuit and the second-stage program-controlled amplifier circuit. The waveform data storage unit is connected to the processor unit. After completing the collection of a set of signals and writing the waveform data points into the internal storage unit of the programmable ASIC device, the programmable ASIC device notifies the processor unit to read the waveform data points, and the processor The unit stores the waveform data points read from the internal storage unit of the programmable ASIC device in the waveform data storage unit. Optionally, the waveform data storage unit can, but is not limited to, use high-speed SRAM or SDRAM to implement its functions.

Optionally, as an optional implementation method of the embodiment of the present invention, during a detection process, the pulse excitation electromagnetic ultrasonic detector can perform multiple excitations and receive multiple ultrasonic echo signals. In each excitation After completing the sampling of the echo signal, the programmable ASIC device sends a command to the processor to read the waveform data points. The processor unit reads the waveform data points from the internal storage unit of the programmable ASIC device and stores them in the waveform data storage unit. The data are superimposed and then re-stored in the waveform data storage unit, thereby achieving the average of the waveform data points collected multiple times.

In the embodiment of the present invention, a charging control circuit is used to quickly charge the high-voltage aluminum electrolytic capacitor to high voltage to provide a high-voltage input signal for the full-bridge high-voltage and high-current switching circuit, thereby achieving a small volume that can provide sufficient high-voltage input for the high-voltage circuit. signal, and at the same time, a full-bridge circuit structure is used to control the limited-period excitation signal of high current generated by the primary side of the high-voltage transformer in a switching amplification manner. The secondary side of the high-voltage transformer can provide high-voltage and high-current driving signals for the electromagnetic ultrasonic sensor, thus achieving a small size The instrument can output high-voltage and high-current excitation signals. In the embodiment of the present invention, the high-voltage signal entering the receiving signal conditioning and sampling circuit is limited in amplitude through the limiting circuit, while allowing the weak receiving signal to pass through without distortion, and is further amplified through a low-noise preamplifier and a fixed gain circuit. , after the signal is adjusted to a certain voltage range, the interference signal in the signal is filtered out, and the program-controlled amplifier circuit amplifies it to the effective range, so that the sampling circuit can perform analog-to-digital conversion of the received signal. At the same time, the present invention The received signal conditioning and sampling circuit in the embodiment can also effectively resist the impact of high-voltage and large-current excitation signals.

Figure 2 is a work flow chart of an optional pulse excitation electromagnetic ultrasonic detector according to an embodiment of the present invention. As shown in Figure 2, in the embodiment of the present invention, ARM is used as the processor unit and FPGA is used as the processor unit. To program ASIC devices, SRAM is used as the waveform data storage unit. The work flow of the pulse excitation electromagnetic ultrasonic detector according to the embodiment of the present invention mainly includes the following steps:

Step S201, start. The material to be tested is detected by the pulse excitation electromagnetic ultrasonic detector according to the embodiment of the present invention. Optionally, the detector can be used to detect the thickness of the material to be tested.

Step S202: ARM receives parameters and writes the parameters into FPGA. ARM first receives parameters through the parameter input interface and writes the parameters into the FPGA. Specifically, ARM uses the value of the average times as the average times global variable, and writes the excitation frequency value and gain value into the corresponding excitation frequency register of the FPGA through the bus interface. , In the gain register, the FPGA selects the signal according to the cut-off frequency, controls the cut-off frequency of the band-pass filter, generates a gain setting signal according to the value of the gain register, and determines the gain of the first-level program-controlled amplification circuit and the second-level program-controlled amplification circuit. Set the value in the average register to 1. When the average register is 1, ARM clears all storage cells in the SRAM.

Step S203: FPGA controls the charging of high-voltage aluminum electrolytic capacitors. The FPGA generates a control signal and controls the charging control circuit to quickly charge the high-voltage aluminum electrolytic capacitor through the low-voltage power supply and charge the high-voltage aluminum electrolytic capacitor to high voltage, thereby providing a high-voltage signal for the full-bridge high-voltage and high-current switching circuit.

Step S204, the FPGA generates four transmission control digital signals, and controls the transmission circuit to output an excitation signal according to the four transmission control digital signals. The FPGA generates four emission control signals based on the excitation frequency in the excitation frequency register, performs analog-to-digital isolation through four high-speed isolation circuits and converts them into four analog signals, and inputs the four analog signals to four voltage and current amplification circuits. The current amplification circuit amplifies four analog signals to obtain four drive signals, thereby driving the full-bridge high-voltage and high-current switching circuit to generate high-voltage and high-current limited period pulse signals at the two input ends of the high-voltage transformer circuit, and then generates a high-voltage and high-current limited period pulse signal on the secondary side of the transformer. High voltage and high current excitation signal.

The electromagnetic ultrasonic sensor generates ultrasound according to the excitation signal, propagates it in the material to be measured, receives the weak ultrasonic echo signal, and outputs the received signal to the receiving signal conditioning and sampling circuit. The received signal conditioning and sampling circuit processes and performs analog-to-digital conversion on the received echo signal. The limiting circuit attenuates the high-voltage and high-current signals in the received echo signal at a larger amplitude, amplifies the weak electromagnetic ultrasonic detection signal by a large factor, and inputs it into the preamplifier, which then amplifies the detection signal. Preamplification is carried out, and the fixed gain amplification circuit is used to amplify again, and then a band-pass filter circuit is used to attenuate the interference signal respectively, and then the first-level program-controlled amplification circuit and the second-level program-controlled large circuit are used for amplification, and finally a low-level Anti-aliasing filtering is performed through the filter circuit to obtain the processed detection signal, which is an analog signal.

At the starting moment when the FPGA transmits the 4-channel transmission control digital signal, the synchronous control sampling circuit performs analog-to-digital conversion on the above-mentioned processed detection signal to obtain waveform data points, which are stored inside the FPGA in sequence until a set of waveform data points is collected. .

Step S205: ARM sequentially reads the waveform data points from the FPGA, reads the data at the corresponding position from the SRAM, superimposes it, and then stores the result into the corresponding position in the SRAM. After the collection of a set of waveform data points is completed, the FPGA sends a command to read the waveform data points to the ARM. The ARM reads one waveform data point data from the inside of the FPGA in a bus manner, and reads out a data from the corresponding address unit of the SRAM. After adding it, write the corresponding address unit of SRAM again until ARM has read all the data, and then ARM adds 1 to the value of the average register.

Step S206, determine whether the value of the average register is equal to the average times global variable. If the value of the average register is not equal to the average times global variable, repeat steps S203 to S206.

Step S207, if the value of the average register is equal to the average times global variable, ARM transmits the averaged waveform data points to the waveform data output interface. ARM reads waveform data points from the waveform data storage unit and outputs them through the waveform data output interface. Optionally, the output waveform data can be displayed on the display screen, or the waveform data can be analyzed and processed by a computer.

Step S208, end. Complete an inspection of the material to be tested.

The above serial numbers of the embodiments of the present invention are only for description and do not represent the advantages and disadvantages of the embodiments.

In the above-mentioned embodiments of the present invention, each embodiment is described with its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are only illustrative. For example, the division of the units may be a logical functional division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or may be Integrated into another system, or some features can be ignored, or not implemented. On the other hand, the coupling or direct coupling or communication connection between each other shown or discussed may be through some interfaces, and the indirect coupling or communication connection of the units or modules may be in electrical or other forms.

The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or they may be distributed to multiple units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated units can be implemented in the form of hardware or software functional units.

If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or contributes to the existing technology or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium , including several instructions to cause a computer device (which can be a personal computer, a server or a network device, etc.) to execute all or part of the steps of the method described in various embodiments of the present invention. The aforementioned storage media include: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program code. .

The above are only preferred embodiments of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications can also be made. should be regarded as the protection scope of the present invention.

Claims (10)

1. A pulse excitation type electromagnetic ultrasonic detector, comprising:

a programmable ASIC device configured to generate a plurality of signals, wherein the plurality of signals includes four transmit control signals and a charge control signal;

the voltage conversion circuit is connected with the programmable ASIC device and is used for converting a low-voltage signal into a high-voltage signal when receiving the charging control signal;

the transmitting circuit is connected with the programmable ASIC device and the voltage conversion circuit and is used for generating a high-voltage and high-current excitation signal according to the transmitting control signal and the high-voltage signal;

the electromagnetic ultrasonic sensor is connected with the transmitting circuit and is used for generating an ultrasonic signal according to the excitation signal and receiving an echo signal, wherein the echo signal is a reflected signal when the ultrasonic signal encounters a structural defect to be detected and a boundary in the propagation process;

And the receiving signal conditioning and sampling circuit is connected with the electromagnetic ultrasonic sensor and is used for processing and sampling the echo signals to obtain waveform data points and writing the waveform data points into a storage unit in the programmable ASIC device.

2. The detector of claim 1, wherein the voltage conversion circuit comprises:

a low voltage power supply for providing a low voltage signal;

the charging control circuit is connected with the programmable ASIC device and the low-voltage power supply, and controls the low-voltage power supply to charge the high-voltage capacitor when receiving the charging control signal;

the high-voltage capacitor is connected with the charging control circuit and the transmitting circuit, is charged to high voltage through the low-voltage power supply, and provides the high-voltage signal for the transmitting circuit.

3. The detector of claim 1, wherein the transmit circuit comprises:

the four-way high-speed isolation circuit is connected with the programmable ASIC device, and outputs four-way analog input signals according to the four-way emission control signals, isolates the four-way emission control signals from the four-way analog input signals, wherein the four-way analog input signals comprise a first group of analog input signals and a second group of analog input signals, the first group of analog input signals and the second group of analog input signals respectively comprise two analog input signals with the same polarity, and the polarities of the first group of analog input signals and the second group of analog input signals are opposite;

The four-way voltage and current amplifying circuit is connected with the four-way high-speed isolating circuit and is used for amplifying the first group of analog input signals and the second group of analog input signals to obtain a first group of driving signals and a second group of driving signals;

the full-bridge high-voltage high-current switch circuit is connected with the four-way voltage-current amplifying circuit and the voltage conversion circuit, wherein the voltage conversion circuit provides the high-voltage signal for the full-bridge high-voltage high-current switch circuit, and the full-bridge high-voltage high-current switch circuit adjusts the running state according to the first group of driving signals and the second group of driving signals, and the running state comprises on or off;

the high-voltage transformer conversion circuit is connected with the full-bridge high-voltage high-current switching circuit and is used for generating the excitation signal according to the on or off of the full-bridge high-voltage high-current switching circuit.

4. The detector of claim 3, wherein the full-bridge high-voltage high-current switching circuit comprises:

the first switch group is connected with the four-way voltage current amplifying circuit, and is conducted when the voltage of the first group of driving signals meets a first preset voltage;

And the second switch group is connected with the four-way voltage current amplifying circuit, and is conducted when the voltage of the second group of driving signals meets a second preset voltage.

5. The apparatus according to claim 4, wherein,

the first switch group comprises a left arm high-end switch and a right arm low-end switch, and the left arm high-end switch and the right arm low-end switch are conducted when the voltage of the first group of driving signals meets a first preset voltage;

the second switch group comprises a left arm low-end switch and a right arm high-end switch, and when the voltage of the second group of driving signals meets a second preset voltage, the left arm low-end switch and the right arm high-end switch are conducted.

6. The detector of claim 5, wherein the high voltage transformer switching circuit comprises:

the tuning circuit is connected with the left arm high-end switch and the left arm low-end switch;

the high-voltage transformer, the first end of high-voltage transformer's primary side is connected with tuned circuit, high-voltage transformer's primary side second end with right arm high-end switch with right arm low-end switch is connected, high-voltage transformer's secondary side's first ground connection, high-voltage transformer's secondary side's second end with electromagnetic ultrasonic sensor is connected.

7. The detector of claim 1, wherein the detector further comprises:

the processor unit is connected with the programmable ASIC device and is used for receiving parameters, wherein the programmable ASIC device generates the multipath signals according to the parameters;

and the waveform data storage unit is connected with the processor unit, wherein the processor unit reads the waveform data points from a storage unit inside the programmable ASIC device and stores the waveform data points in the waveform data storage unit.

8. The detector of claim 1, wherein the received signal conditioning and sampling circuit comprises:

the receiving signal conditioning circuit is connected with the electromagnetic ultrasonic sensor and is used for processing the echo signals to obtain processed echo signals;

and the analog-to-digital conversion circuit is connected with the received signal conditioning circuit and is used for sampling the processed echo signals to obtain the waveform data points.

9. The detector of claim 8, wherein the receive signal conditioning circuit comprises:

the amplitude limiting circuit is connected with the electromagnetic ultrasonic sensor;

The low-noise pre-amplifying circuit is connected with the amplitude limiting circuit;

the fixed gain amplifying circuit is connected with the low noise pre-amplifying circuit;

the band-pass filter circuit is connected with the fixed gain amplifying circuit;

the first-stage program-controlled amplifying circuit is connected with the band-pass filter circuit;

the second-stage program-controlled amplifying circuit is connected with the first-stage program-controlled amplifying circuit;

and the low-pass filter circuit is connected with the second-stage program-controlled amplifying circuit.

10. The detector of claim 9, wherein the multipath signal comprises a gain setting signal and a frequency selection signal, and the receive signal conditioning and sampling circuit comprises:

the gain voltage setting circuit is connected with the programmable ASIC device, the first-stage program-controlled amplifying circuit and the second-stage program-controlled amplifying circuit and is used for outputting voltage signals according to the gain setting signals, and the voltage signals are used for setting the gains of the first-stage program-controlled amplifying circuit and the second-stage program-controlled amplifying circuit;

and the cut-off frequency selection circuit is connected with the programmable ASIC device and the band-pass filter circuit and is used for setting the cut-off frequency of the band-pass filter circuit according to the frequency selection signal.