CN108627570A - Digital harmonic excitation source and implementation method - Google Patents
Digital harmonic excitation source and implementation method Download PDFInfo
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Abstract
The invention discloses digital harmonic excitation source and implementation methods, belong to signal excitation source domain, including：Module occurs for main control chip, low frequency signal, module occurs for high-frequency signal, module, signal tie jumper, power-adjustable amplification module, load, harmonic signal acquisition module, LCD MODULE and frequency and voltage regulator module occur for harmonic signal.Prime harmonic RF module includes：Module occurs for main control chip, low frequency signal, module occurs for high-frequency signal, module, LCD MODULE, frequency and voltage regulator module occur for harmonic signal；Rear class power amplifier module includes：Power-adjustable amplification module, harmonic signal acquisition module and load；Prime harmonic RF module is connected with rear class power amplifier module by signal tie jumper.The digital regulated output of harmonic frequency signal and voltage can be achieved in the present invention, and has the function of frequency and voltage liquid crystal real-time display, being capable of accurate, stable output power harmonic signal.
Description
Technical field
The present invention relates to harmonic signal driving source technical fields, and in particular to a kind of digital harmonic excitation source and realization side
Method can realize the harmonic excitation signals for applying specific frequency and power to load, and have the digital adjusting of frequency, output work
Rate adjusts and crystal display, can be applied to the technical field of nondestructive testing of the metal materials such as steel pipe, rail, storage tank,
The technical fields such as the communications field and biomedical inspection.
Background technology
Nondestructive detecting technology of vortex have it is contactless, without couplant, detection speed is fast, receives signal contain it is abundant
The advantages that spectrum information, in terms of the non-destructive testing for being widely used in ferrimagnet.Eddy detection technology includes：Single-frequency whirlpool
Detection technique, multi frequency detection technology, Far Field Swirl Detecting Technology and Pulsed eddy current testing technology etc. are flowed, has been applied to each
Kind field of non destructive testing, and achieve good effect.The plurality of advantages of above-mentioned eddy detection technology determines that EDDY CURRENT is used
The critical role of driving source.
Currently, traditional eddy detection technology mostly uses the high frequency sinusoidal signal of single-frequency or multifrequency as driving source, due to height
The Kelvin effect of frequency signal leads to not the total wall thickness detection for realizing test specimen；In addition, conventional driver source does not have digital
Frequency and voltage value function are adjusted, signal stabilization is poor, of high cost, and power volume is larger, and real-time without frequency and power
The function of adjusting and show, and the function that digital adjusting is important in being designed as driving source with real-time display function, directly certainly
Determine the property easy to use of driving source.
Invention content
To solve the above problems, the present invention provides a kind of digital harmonic excitation source and implementation methods, it is therefore intended that real
Now using Low Frequency Sine Signals as carrier wave, high frequency sinusoidal signal is the harmonic signal driving source of detection waveform；The harmonic excitation source energy
It enough realizes the total wall thickness detection in steel pipe and metal specimen, has the advantages that detection sensitivity height and penetration capacity are strong.
To achieve the above object, the present invention provides a kind of digital harmonic excitation source, including prime harmonic RF module
(11) and rear class power amplifier module (12)；
The prime harmonic RF module (11) includes main control chip (1), low frequency signal generation module (2), high-frequency signal
Module (3) occurs, module (4) and frequency and voltage regulator module (10) occur for harmonic signal；
Respectively module (2) occurs with the low frequency signal for the main control chip (1), high-frequency signal occurs module (3) and is connected,
Frequency described in being connected with two groups on the main control chip (1) and voltage regulator module (10)；Frequency described in one group is adjusted with voltage
Module (10) is used to adjust the frequency and amplitude of Low Frequency Sine Signals, and frequency described in another group is used for voltage regulator module (10)
Adjust the frequency and amplitude of high frequency sinusoidal signal；
The output end of the low frequency input terminal and low frequency signal generation module (1) of module (4) occurs for the harmonic signal
The output end that module (2) occurs with the high-frequency signal for connected, high frequency input terminal is connected, for what is be made up of operational amplifier
Addition summing circuit carries out harmonic management, and output harmonic wave signal source to Low Frequency Sine Signals and high frequency sinusoidal signal；
The rear class power amplifier module (12) includes the power-adjustable being made of power amplifier chip and its peripheral circuit
Amplification module (6), load (7) and harmonic wave signal acquisition module (8)；
The input terminal of the power-adjustable amplification module (6) is occurred by signal tie jumper (5) and the harmonic signal
The output end of module (4) is connected, output end is connected with the load (7)；The harmonic signal acquisition module (8) respectively with it is described
Load (7) is connected with main control chip (1), for acquiring load (7) both ends harmonic signal voltage value and being transferred to the master
Control chip (1).
As a further improvement on the present invention, the prime harmonic RF module (11) further includes LCD MODULE (9)；
The LCD MODULE (9) is connected by bus with the main control chip (1), for showing Low Frequency Sine Signals
Frequency, high frequency sinusoidal signal higher frequency and acquisition load (7) both ends harmonic voltage.
As a further improvement on the present invention, the main control chip (1) is STM32 main control chips, the low frequency signal hair
The structure that module (3) occurs with high-frequency signal for raw module (2) is identical, is same model direct digital synthesis technique chip DDS
And parameter having the same and function.
As a further improvement on the present invention, it includes sinusoidal signal generator, number that module (2), which occurs, for the low frequency signal
Potentiometer, operational amplifier IC3, resistance R5~R6 and capacitance C2, the frequency include external letter with voltage regulator module (10)
Number input equipment (15), external signal input devices (15) are equipped with for increasing the button S1 of sinusoidal signal frequency, for subtracting
The button S2 of small sinusoidal signal frequency, the button S3 for increasing sinusoidal signal voltage peak-to-peak value and for reduce sinusoidal signal electricity
The button S4 of voltage crest peak value；
The external signal input devices (15) are connected with the controlling switch of main control chip (1), main control chip (1) respectively with
Sinusoidal signal generator is connected with the control terminal of digital regulation resistance, the OUT pins of sinusoidal signal generator and digital regulation resistance
The ends PB are connected, and the ends PA of digital regulation resistance are connected with the in-phase input end of operational amplifier IC3, the reverse phase of operational amplifier IC3
Input terminal is connected through resistance R5 with the output end of operational amplifier IC3, and the inverting input of operational amplifier IC3 is through R6 and GND
End is connected, and the positive power end of operational amplifier IC3 is connected by capacitance C2 and the ends GND；
Sinusoidal signal generator output voltage VDDSWith operational amplifier IC3 output voltages Vout1Proportionate relationship be：
As a further improvement on the present invention, the harmonic signal occur module (4) include operational amplifier IC2A~
IC2B, resistance R1~R4 and capacitance C1；
After the low frequency input terminal connection resistance R1 of module (4), high frequency input terminal connection resistance R2 occur for the harmonic signal,
Parallel connection is input to the inverting input of operational amplifier IC2A, and the output end of operational amplifier IC2A is through resistance R4 and anti-phase input
End is connected, and the in-phase input end of operational amplifier IC2A is connected through resistance R3 with the ends GND；The output end of operational amplifier IC2A passes through
Capacitance C1 is connected with the in-phase input end of operational amplifier IC2B, output end and the inverting input phase of operational amplifier IC2B
Even, the output end output harmonic wave signal source of operational amplifier IC2B.
As a further improvement on the present invention, the signal tie jumper (5) is parallel two-wire system link, respectively positive
With cathode tie jumper；Wherein, front end is connected to prime harmonic RF module (11), and rear end is connected to rear class power amplifier module
(12)。
As a further improvement on the present invention, the power-adjustable amplification module (6) is by signal amplification module (13) and work(
Rate amplification module (14) forms, and the input terminal of the signal amplification module (13) passes through signal tie jumper (5) and the harmonic wave
The output end of signal generating module (4) is connected, output end is connected with the input terminal of the power amplifier module (14), the power
The output end of amplification module (14) is connected with the load (7)；
The signal amplification module (13) is made of second order voltage controlled voltage source low-pass filter comprising operational amplifier
IC4A~IC4B, resistance R10~R14, adjustable resistance RPWith capacitance C11~C12；Adjustable resistance RPA fixing end and the letter
After the input terminal of number amplification module (13) is connected, another fixing end is connected with the ends GND, adjustable end is connected with resistance R10 with operation
The inverting input of amplifier IC4A is connected, and the inverting input of operational amplifier IC4A is connected through resistance R14 with output end, fortune
The in-phase input end for calculating amplifier IC4A is connected through resistance R13 with the ends GND；The output end of operational amplifier IC4A is through being in series
Be connected with the in-phase input end of operational amplifier IC4B after resistance R11, R12, the inverting input of operational amplifier IC4B with it is defeated
Outlet is connected, and resistance R11 right ends draw foot meridian capacitor C11 and are connected with the output end of operational amplifier IC4B, resistance R12 right end pins
It is connected with the ends GND through capacitance C12；
The power amplifier module (14) includes that power amplifier IC5, resistance R15~R21 and capacitance C3~C6, operation are put
The output end of big device IC4B is connected through resistance R15 with the in-phase input end of power amplifier IC5, the same phase of power amplifier IC5
Input terminal is connected through capacitance C3 with inverting input, resistance R16, electricity of the inverting input through being in series of power amplifier IC5
Be connected with the ends GND after resistance R17, after resistance R16, the resistance R18 of the inverting input of power amplifier IC5 through being in series with output
End is connected, after resistance R16 through being in series of the inverting input of power amplifier IC5, capacitance C4, resistance R19 with output end phase
Even, it is connected with the ends GND after capacitance C5, resistance R20 of the output end of power amplifier IC5 through being in series, power amplifier IC5's
It is connected with the load (7) after resistance R21, capacitance C6 of the output end through being in series.
As a further improvement on the present invention, the value of resistance R11, capacitance C11 and resistance R12, capacitance C12 are：
According to cutoff frequency fo, β=1, resistance R11=R12=10(2-4)Ω determines capacitance C11 value models by formula (1)
It encloses：
Capacitance C11 is according to existing capacitance value：
According to parameterβ=1, unit gain AF=1, capacitance C12 value ranges are obtained by formula (2)：
Wherein,
The resistance value of resistance R11 and R12 is determined according to formula (3)：
The power amplification multiple of power amplifier IC5 is：Pass through adjustable resistance RPWork(
Rate adjusting knob adjusts harmonic signal power variation.
As a further improvement on the present invention, the harmonic signal acquisition module (8) includes ABS4 rectifier bridges and resistance R7
~R9；
The input terminal of the harmonic signal acquisition module (8) connect with resistance R7, the R8 being in parallel after through resistance R9 and GND
End is connected, and the exchange electrode input end of ABS4 rectifier bridges is connected with the left end pin of resistance R9, exchanges negative input and direct current
Cathode output end is connected with the ends GND, direct-flow positive pole output end is connected with main control chip (1)；
Analog input end input voltage VADCWith harmonic voltage VOUTRelationship be：
The present invention also provides a kind of implementation methods in digital harmonic excitation source, including：
Step 1 realizes that module (2) occurs for low frequency signal and the common output voltage amplitude phase of module (3) occurs for high-frequency signal
Deng low frequency and high_frequency sine wave signal；
Step 2, harmonic signal occur module (4) and realize that high-frequency signal carrier wave is exported to the harmonic signal source of low frequency signal,
And the frequency and voltage value of low frequency and high-frequency signal are adjusted by frequency and voltage regulator module (10)；
Step 3, harmonic signal source are entered by signal tie jumper (5) in rear class power amplifier module (12), to harmonic wave
Signal carries out power amplification；Harmonic signal acquisition module (8) acquisition simultaneously handles load (7) both ends harmonic signal voltage value, and by
LCD MODULE (9) is shown.
Compared with prior art, beneficial effects of the present invention are：
In digital harmonic excitation source design aspect, the present invention is based on main control chip, signal generating module and harmonic signals
Module output harmonic wave signal source occurs, has frequency resolution high, delay is small, the advantage that harmonic signal is stablized；Meanwhile the harmonic wave
DIGITAL FREQUENCY adjustment module, LCD MODULE and power-adjustable amplification module is added in driving source so that the harmonic excitation
Source has the advantages that easier, stable and reliable in terms of frequency, signal amplitude and power regulation；Machine debugging passes through program
It completes, it is simple in structure to have, debug convenient advantage；
In non-destructive testing application aspect, harmonic excitation source can be exported using low frequency signal as carrier wave, and high-frequency signal is detection
The harmonic signal of waveform is believed using the low Kelvin effect of low frequency signal and the high-frequency detection of strong penetrability carrier wave high detection sensitivity
Number realize steel pipe total wall thickness detection, to realize effective detection of steel pipe damaged portion.
Description of the drawings
Fig. 1 is the structural schematic diagram in digital harmonic excitation source disclosed in an embodiment of the present invention；
Fig. 2 is main control chip in Fig. 1, low frequency signal generation module, LCD MODULE and frequency and voltage regulator module
Circuit diagram；
Fig. 3 is the circuit diagram that module occurs for harmonic signal in Fig. 1；
Fig. 4 is the two-stage circuit schematic diagram of power-adjustable amplification module in Fig. 1；
Fig. 5 is the circuit diagram of harmonic signal acquisition module in Fig. 1.
In figure：
1, main control chip；2, module occurs for low frequency signal；3, module occurs for high-frequency signal；4, module occurs for harmonic signal；
5, signal tie jumper；6, power-adjustable amplification module；7, it loads；8, harmonic signal acquisition module；9, LCD MODULE；
10, frequency and voltage regulator module；11, prime harmonic RF module；12, rear class power amplifier module；13, signal amplifies mould
Block；14, power amplifier module；15, external signal input devices.
Specific implementation mode
In order to make the object, technical scheme and advantages of the embodiment of the invention clearer, below in conjunction with the embodiment of the present invention
In attached drawing, technical scheme in the embodiment of the invention is clearly and completely described, it is clear that described embodiment is
A part of the embodiment of the present invention, instead of all the embodiments.Based on the embodiments of the present invention, ordinary skill people
The every other embodiment that member is obtained without making creative work, shall fall within the protection scope of the present invention.
The present invention is described in further detail below in conjunction with the accompanying drawings：
The present invention proposes a kind of digital harmonic signal driving source and implementation method, the driving source have digital adjusting and
The function of real-time display harmonic signal output frequency and amplitude, and can be by the volume defining of complete machine to a very small extent；Together
When, which is deeply detected using the high-frequency signal of the low frequency signal carrier wave high sensitivity of low Kelvin effect, to reach
Realize the total wall thickness detection of steel pipe.
As shown in Figure 1, the present invention provides a kind of digital harmonic excitation source, including prime harmonic RF module 11 and rear class
Power amplifier module 12；Prime harmonic RF module 11 is placed in before rear class power amplifier module 12, is two groups of separate modules, and
It is connected by signal tie jumper 5；Wherein：
The prime harmonic RF module 11 of the present invention includes main control chip 1, module 2 occurs for low frequency signal, high-frequency signal is sent out
Module 4, LCD MODULE 9 and frequency and voltage regulator module 10 occur for raw module 3, harmonic signal；Main control chip 1 respectively with
Module 2 occurs for low frequency signal, high-frequency signal occurs module 3 and is connected, and two class frequencys are connected on main control chip 1 and adjust mould with voltage
Block 10；A set of frequencies is used to adjust the frequency and amplitude of Low Frequency Sine Signals, another class frequency and electricity with voltage regulator module 10
Pressure adjustment module 10 is used to adjust the frequency and amplitude of high frequency sinusoidal signal, and LCD MODULE 9 passes through bus and main control chip 1
It is connected；The output end that low frequency input terminal and low frequency signal the generation module 1 of module 4 occur for harmonic signal is connected, high frequency input terminal
The output end that module 2 occurs with high-frequency signal is connected, is used for the addition summing circuit that is made up of operational amplifier to low frequency just
String signal and high frequency sinusoidal signal carry out harmonic management, and output harmonic wave signal source；
The present invention rear class power amplifier module 12 include by power amplifier chip and its peripheral circuit constitute can Power Regulation
Rate amplification module 6, load 7 and harmonic wave signal acquisition module 8；The input terminal of power-adjustable amplification module 6 is connected by signal and is jumped
The output end that module 4 occurs with harmonic signal for line 5 is connected, output end is connected with load 7；Harmonic signal acquisition module 8 respectively with
Load 7 is connected with main control chip 1, for acquiring 7 both ends harmonic signal voltage values of load and being transferred to main control chip 1, and in liquid
Brilliant display module 9 is shown.Specifically：
As shown in Fig. 2, the main control chip 1 of the present invention is STM32 chips, main control chip 1 passes through SPI interface and low frequency signal
Module 2 occurs with high-frequency signal generation module 3 to be connected, module 2 occurs for low frequency signal and high-frequency signal occurs module 3 and connects frequency conjunction
Grow up to be a useful person DDS and its peripheral circuit composition, low frequency signal occur module 2 and high-frequency signal occur module 3 structure it is identical and have
Identical parameter and function are only illustrated so that module 2 occurs for low frequency signal as an example in Fig. 2.The low frequency signal of the present invention occurs
Module 2 and high-frequency signal occur module 3 and mould occur for generating Low Frequency Sine Signals and high frequency sinusoidal signal, low frequency signal respectively
Block 2 includes sinusoidal signal generator, digital regulation resistance, operational amplifier IC3, resistance R5~R6 and capacitance C2, main control chip 1
SPI interface is connected with the control terminal of sinusoidal signal generator and digital regulation resistance respectively, the OUT pins of sinusoidal signal generator with
The ends PB of digital regulation resistance are connected, and the ends PA of digital regulation resistance are connected with the in-phase input end of operational amplifier IC3, operation amplifier
The inverting input of device IC3 is connected through resistance R5 with the output end of operational amplifier IC3, the anti-phase input of operational amplifier IC3
End is connected through R6 with the ends GND, and the positive power end of operational amplifier IC3 is connected by capacitance C2 and the ends GND, operational amplifier IC3
Supply voltage be ± 5V；Sinusoidal signal generator output voltage VDDSWith operational amplifier IC3 output voltages Vout1Ratio close
System is：
As shown in Fig. 2, the frequency of the present invention includes external signal input devices 15, external signal with voltage regulator module 10
Input equipment 15 is connected with the controlling switch of main control chip 1, and provides frequency and voltage adjusting control signal to main control chip 1；
Main control chip 1 adjusts the frequency of sinusoidal signal generator output signal according to frequency control signal, according to voltage control signal tune
Joint number word potentiometer resistance size and then control output voltage Vout1.Include four buttons in external signal input devices 15,
It is respectively for increasing the button S1 of sinusoidal signal frequency, the button S2 for reducing sinusoidal signal frequency, for increasing just
The button S3 of string signal voltage peak-to-peak value and button S4 for reducing sinusoidal signal voltage peak-to-peak value.The frequency of the present invention and electricity
Pressure adjustment module 10 is made of above structure two parts module identical with parameter, controls low frequency signal respectively and module 2 occurs
The frequency and voltage of module 3 occur with high-frequency signal.
As shown in Fig. 2, the LCD MODULE 9 of the present invention is liquid crystal display, by data/address bus and address bus with
Main control chip 1 connects；Meanwhile the particular content that LCD MODULE 9 is shown is：Frequency, the high frequency of Low Frequency Sine Signals
The harmonic voltage of the higher frequency of sinusoidal signal and 7 both ends of load of acquisition.
As shown in figure 3, the present invention harmonic signal occur module 4 include operational amplifier IC2A~IC2B, resistance R1~
The supply voltage of R4 and capacitance C1, operational amplifier IC2A~IC2B are ± 15V；The low frequency input of module 4 occurs for harmonic signal
After end connection resistance R1, high frequency input terminal connection resistance R2, parallel connection is input to the inverting input of operational amplifier IC2A, operation
The output end of amplifier IC2A is connected through resistance R4 with inverting input, and the in-phase input end of operational amplifier IC2A is through resistance R3
It is connected with the ends GND；The output end of operational amplifier IC2A is connected through capacitance C1 with the in-phase input end of operational amplifier IC2B, fortune
The output end for calculating amplifier IC2B is connected with inverting input, the output end output harmonic wave signal source of operational amplifier IC2B；Its
In, the harmonic signal source that 4 output end output voltage peak-to-peak value of module is 4V occurs for harmonic signal.
As shown in Figure 1, the signal tie jumper 5 of the present invention is parallel two-wire system link, respectively positive electrode and negative electrode connect
Wire jumper；Wherein, front end is connected to prime harmonic RF module 11, and rear end is connected to rear class power amplifier module 12.
As shown in figure 4, the power-adjustable amplification module 6 of the present invention is by 14 groups of signal amplification module 13 and power amplifier module
At the input terminal of signal amplification module 13 is connected with the output end of harmonic signal generation module 4 by signal tie jumper 5, is defeated
Outlet is connected with the input terminal of power amplifier module 14, and the output end of power amplifier module 14 is connected with load 7；Wherein：
Signal amplification module 13 constitutes reverse phase proportion operational amplifier by operational amplifier IC4A~IC4B (OPA2604AP)
With second order voltage controlled voltage source low-pass filter.It includes operational amplifier IC4A~IC4B, resistance R10~R14, adjustable resistance RP
Supply voltage with capacitance C11~C12, operational amplifier IC4A~IC4B is ± 15V；Adjustable resistance RPA fixing end with letter
It is put with operation after the input terminal of number amplification module 13 is connected, another fixing end is connected with the ends GND, adjustable end is connected with resistance R10
The inverting input of big device IC4A is connected, and the inverting input of operational amplifier IC4A is connected through resistance R14 with output end, operation
The in-phase input end of amplifier IC4A is connected through resistance R13 with the ends GND, and the amplification factor of reverse phase ratio amplifier is：The output end of operational amplifier IC4A is same with operational amplifier IC4B after resistance R11, R12 through being in series
Phase input terminal is connected, and the inverting input of operational amplifier IC4B is connected with output end, and resistance R11 right ends draw foot meridian capacitor C11
It is connected with the output end of operational amplifier IC4B, resistance R12 right ends draw foot meridian capacitor C12 and are connected with the ends GND, resistance R11, capacitance
C11 and resistance R12, capacitance C12 form Order RC filter, and IC4B forms voltage follower, and it is voltage-controlled that two groups of circuits constitute second order
Voltage source low-pass filter.
The value of resistance R11, capacitance C11 and resistance R12, capacitance C12 are in Order RC filter：
According to cutoff frequency fo, β=1, resistance R11=R12=10(2-4)Ω determines capacitance C11 value models by formula (1)
It encloses：
Capacitance C11 is about according to existing capacitance value：
According to parameterβ=1, unit gain AF=1, capacitance C12 value ranges are obtained by formula (2)：
Wherein,
The resistance value of resistance R11 and R12 is determined according to formula (3)：
The power amplifier module 14 of the present invention includes power amplifier IC5 (LM3886TF), resistance R15~R21 and capacitance
The supply voltage of C3~C6, power amplifier IC5 are ± 36V；The output end of operational amplifier IC4B is put through resistance R15 with power
The in-phase input end of big device IC5 is connected, and the in-phase input end of power amplifier IC5 is connected through capacitance C3 with inverting input, work(
The inverting input of rate amplifier IC5 is connected after resistance R16, the resistance R17 through being in series with the ends GND, power amplifier IC5's
Inverting input is connected after resistance R16, the resistance R18 through being in series with output end, the inverting input warp of power amplifier IC5
It is connected with output end after the resistance R16 that is in series, capacitance C4, resistance R19, the output end of power amplifier IC5 is through being in series
It is connected with the ends GND after capacitance C5, resistance R20, the output end of power amplifier IC5 is after resistance R21, the capacitance C6 through being in series
Harmonic signal output end, and be connected with load 7；The power amplification multiple of power amplifier IC5 is：Pass through adjustable resistance RPPower regulating knob adjust harmonic signal power variation.
As shown in figure 5, the harmonic signal acquisition module 8 of the present invention includes ABS4 rectifier bridges and resistance R7~R9；Harmonic wave is believed
The input terminal of number acquisition module 8 is connected through resistance R9 with the ends GND after being connect with resistance R7, the R8 being in parallel, ABS4 rectifier bridges
Exchange electrode input end (AC+) is connected with the left end pin of resistance R9, i.e. A points in Fig. 5, exchange negative input (AC-) and
Direct current cathode output end (DC-) is connected with the ends GND, the ADC module channel of direct-flow positive pole output end (DC+) and main control chip 1
It is connected；Harmonic signal acquisition module 8 is parallel to 7 both ends of load, and accurate partial pressure is carried out to harmonic signal, and current limliting turns direct current with exchanging
Operation.Resistance R7 and R8 are precision resistance in harmonic signal acquisition module 8；ABS4 rectifier bridge parameters are：Reverse phase repeats peak
Threshold voltage (VRRM) it is 400V, maximum voltage virtual value (VRMS) it is 280V, maximum direct-current blocking-up voltage (VDC) it is 400V, forward direction is flat
Equal electric current (IF) it is 1A, Peak Forward Surge Current (IFSM) it is 30A.Harmonic signal acquisition module 8 obtains within the scope of 0V~3V
Analog voltage signal is converted to digital quantity by the analog-to-digital conversion module of main control chip 1, realizes output harmonic wave signal voltage value
Number display.
The present invention also provides a kind of implementation methods in digital harmonic excitation source, including：
Step 1 realizes that low frequency signal generation module 2 is equal with high-frequency signal generation 3 common output voltage amplitude of module
Low frequency and high_frequency sine wave signal；
Step 2, harmonic signal occur module 4 and realize that high-frequency signal carrier wave is exported to the harmonic signal source of low frequency signal, and
The frequency and voltage value of low frequency and high-frequency signal are adjusted by frequency and voltage regulator module 10；
Step 3, harmonic signal source are entered by signal tie jumper 5 in rear class power amplifier module 12, to harmonic signal
Carry out power amplification；Harmonic signal acquisition module 8 acquires and handles 7 both ends harmonic signal voltage values of load, and by liquid crystal display
Module 9 is shown；Wherein, resistance R7, R8 and R9 are high-power resistance in harmonic signal acquisition module 8, and analog input end is defeated
Enter voltage VADCWith harmonic voltage VOUTRelationship be：
Beneficial effects of the present invention are：
In digital harmonic excitation source design aspect, the present invention is based on main control chip STM32, signal generating modules (directly
Digital synthesis chip DDS) and harmonic wave signal generating module output harmonic wave signal source, have frequency resolution high, delay is small, humorous
The advantages of wave signal stabilization；Meanwhile DIGITAL FREQUENCY adjustment module, LCD MODULE and adjustable is added in the harmonic excitation source
Power amplifier module so that the harmonic excitation source in terms of frequency, signal amplitude and power regulation have it is easier, stablize and
Reliable advantage；Machine debugging is completed by program, simple in structure to have, and debugs convenient advantage；
In non-destructive testing application aspect, harmonic excitation source can be exported using low frequency signal as carrier wave, and high-frequency signal is detection
The harmonic signal of waveform is believed using the low Kelvin effect of low frequency signal and the high-frequency detection of strong penetrability carrier wave high detection sensitivity
Number realize steel pipe total wall thickness detection, to realize effective detection of steel pipe damaged portion.
It these are only the preferred embodiment of the present invention, be not intended to restrict the invention, for those skilled in the art
For member, the invention may be variously modified and varied.Any modification made by all within the spirits and principles of the present invention,
Equivalent replacement, improvement etc., should all be included in the protection scope of the present invention.
Claims (10)
1. a kind of digital harmonic excitation source, which is characterized in that including prime harmonic RF module (11) and rear class power amplification
Module (12)；
The prime harmonic RF module (11) includes main control chip (1), module (2) occurs for low frequency signal, high-frequency signal occurs
Module (4) and frequency and voltage regulator module (10) occur for module (3), harmonic signal；
Respectively module (2) occurs with the low frequency signal for the main control chip (1), high-frequency signal occurs module (3) and is connected, described
Frequency described in being connected with two groups on main control chip (1) and voltage regulator module (10)；Frequency and voltage regulator module described in one group
(10) it is used to adjust the frequency and amplitude of Low Frequency Sine Signals, frequency described in another group is with voltage regulator module (10) for adjusting
The frequency and amplitude of high frequency sinusoidal signal；
The low frequency input terminal that module (4) occurs for the harmonic signal is connected with the output end of low frequency signal generation module (1),
The output end that module (2) occurs with the high-frequency signal for high frequency input terminal is connected, the addition for being made up of operational amplifier
Summing circuit carries out harmonic management, and output harmonic wave signal source to Low Frequency Sine Signals and high frequency sinusoidal signal；
The rear class power amplifier module (12) includes the power-adjustable amplification being made of power amplifier chip and its peripheral circuit
Module (6), load (7) and harmonic wave signal acquisition module (8)；
By signal tie jumper (5) and the harmonic signal module occurs for the input terminal of the power-adjustable amplification module (6)
(4) output end is connected, output end is connected with the load (7)；The harmonic signal acquisition module (8) respectively with the load
(7) it is connected with main control chip (1), for acquiring load (7) both ends harmonic signal voltage value and being transferred to the master control core
Piece (1).
2. digital harmonic excitation source as described in claim 1, which is characterized in that the prime harmonic RF module (11) is also
Including LCD MODULE (9)；
The LCD MODULE (9) is connected by bus with the main control chip (1), for showing the low of Low Frequency Sine Signals
The harmonic voltage at load (7) both ends of frequent rate, the higher frequency of high frequency sinusoidal signal and acquisition.
3. digital harmonic excitation source as described in claim 1, which is characterized in that the main control chip (1) is STM32 master controls
Chip, the structure that module (3) occurs with high-frequency signal for the low frequency signal generation module (2) is identical, is that same model is direct
Digital Frequency Synthesize chip DDS and parameter having the same and function.
4. digital harmonic excitation source as claimed in claim 3, which is characterized in that the low frequency signal occurs module (2) and wraps
Include sinusoidal signal generator, digital regulation resistance, operational amplifier IC3, resistance R5~R6 and capacitance C2, the frequency and voltage tune
Mould preparation block (10) includes external signal input devices (15), and external signal input devices (15) are equipped with for increasing sinusoidal signal
The button S1 of frequency, the button S2 for reducing sinusoidal signal frequency, the button S3 for increasing sinusoidal signal voltage peak-to-peak value
With the button S4 for reducing sinusoidal signal voltage peak-to-peak value；
The external signal input devices (15) are connected with the controlling switch of main control chip (1), main control chip (1) respectively with sine
Signal generator is connected with the control terminal of digital regulation resistance, the OUT pins of sinusoidal signal generator and the ends PB of digital regulation resistance
It is connected, the ends PA of digital regulation resistance are connected with the in-phase input end of operational amplifier IC3, the anti-phase input of operational amplifier IC3
End is connected through resistance R5 with the output end of operational amplifier IC3, and the inverting input of operational amplifier IC3 is through the ends R6 and GND phase
Even, the positive power end of operational amplifier IC3 is connected by capacitance C2 and the ends GND；
Sinusoidal signal generator output voltage VDDSWith operational amplifier IC3 output voltages Vout1Proportionate relationship be：
5. digital harmonic excitation source as described in claim 1, which is characterized in that the harmonic signal occurs module (4) and wraps
Include operational amplifier IC2A~IC2B, resistance R1~R4 and capacitance C1；
It is in parallel after the low frequency input terminal connection resistance R1 of module (4), high frequency input terminal connection resistance R2 occur for the harmonic signal
It is input to the inverting input of operational amplifier IC2A, the output end of operational amplifier IC2A is through resistance R4 and inverting input phase
Even, the in-phase input end of operational amplifier IC2A is connected through resistance R3 with the ends GND；The output end of operational amplifier IC2A is through capacitance
C1 is connected with the in-phase input end of operational amplifier IC2B, and the output end of operational amplifier IC2B is connected with inverting input, fortune
Calculate the output end output harmonic wave signal source of amplifier IC2B.
6. digital harmonic excitation source as described in claim 1, which is characterized in that the signal tie jumper (5) is parallel
Two-wire system link, respectively positive electrode and negative electrode tie jumper；Wherein, front end is connected to prime harmonic RF module (11), rear end
It is connected to rear class power amplifier module (12).
7. digital harmonic excitation source as described in claim 1, which is characterized in that the power-adjustable amplification module (6) by
Signal amplification module (13) and power amplifier module (14) composition, the input terminal of the signal amplification module (13) are connected by signal
Connect wire jumper (5) and the harmonic signal occur module (4) output end be connected, output end and the power amplifier module (14)
Input terminal is connected, and the output end of the power amplifier module (14) is connected with the load (7)；
The signal amplification module (13) is made of second order voltage controlled voltage source low-pass filter comprising and operational amplifier IC4A~
IC4B, resistance R10~R14, adjustable resistance RPWith capacitance C11~C12；Adjustable resistance RPA fixing end and the signal amplify
After the input terminal of module (13) is connected, another fixing end is connected with the ends GND, adjustable end is connected with resistance R10 with operational amplifier
The inverting input of IC4A is connected, and the inverting input of operational amplifier IC4A is connected through resistance R14 with output end, operation amplifier
The in-phase input end of device IC4A is connected through resistance R13 with the ends GND；Resistance of the output end of operational amplifier IC4A through being in series
It is connected with the in-phase input end of operational amplifier IC4B after R11, R12, the inverting input and output end of operational amplifier IC4B
It is connected, resistance R11 right ends draw foot meridian capacitor C11 and are connected with the output end of operational amplifier IC4B, and resistance R12 right end pins are through electricity
Hold C12 with the ends GND to be connected；
The power amplifier module (14) includes power amplifier IC5, resistance R15~R21 and capacitance C3~C6, operational amplifier
The output end of IC4B is connected through resistance R15 with the in-phase input end of power amplifier IC5, the homophase input of power amplifier IC5
End is connected through capacitance C3 with inverting input, resistance R16, resistance R17 of the inverting input through being in series of power amplifier IC5
Be connected afterwards with the ends GND, after resistance R16, the resistance R18 of the inverting input of power amplifier IC5 through being in series with output end phase
Even, it is connected with output end after resistance R16 through being in series of the inverting input of power amplifier IC5, capacitance C4, resistance R19, work(
The output end of rate amplifier IC5 is connected after capacitance C5, the resistance R20 through being in series with the ends GND, the output of power amplifier IC5
It is connected with the load (7) after holding resistance R21, capacitance C6 through being in series.
8. digital harmonic excitation source as claimed in claim 7, which is characterized in that resistance R11, capacitance C11 and resistance R12,
The value of capacitance C12 is：
According to cutoff frequency fo, β=1, resistance R11=R12=10(2-4)Ω determines capacitance C11 value ranges by formula (1)：
Capacitance C11 is according to existing capacitance value：
According to parameterβ=1, unit gain AF=1, capacitance C12 value ranges are obtained by formula (2)：
Wherein,
The resistance value of resistance R11 and R12 is determined according to formula (3)：
The power amplification multiple of power amplifier IC5 is：Pass through adjustable resistance RPPower regulation
Knob adjusts harmonic signal power variation.
9. digital harmonic excitation source as described in claim 1, which is characterized in that harmonic signal acquisition module (8) packet
Include ABS4 rectifier bridges and resistance R7~R9；
The input terminal of the harmonic signal acquisition module (8) connect with resistance R7, the R8 being in parallel after through the ends resistance R9 and GND phase
Even, the exchange electrode input end of ABS4 rectifier bridges is connected with the left end pin of resistance R9, exchanges negative input and direct current cathode
Output end is connected with the ends GND, direct-flow positive pole output end is connected with main control chip (1)；
Analog input end input voltage VADCWith harmonic voltage VOUTRelationship be：
10. a kind of implementation method in digital harmonic excitation source as claimed in any one of claims 1-9 wherein, which is characterized in that
Including：
Step 1 realizes that module (2) occurs for low frequency signal and the common output voltage amplitude of high-frequency signal generation module (3) is equal
Low frequency and high_frequency sine wave signal；
Step 2, harmonic signal occur module (4) and realize that high-frequency signal carrier wave is exported to the harmonic signal source of low frequency signal, and lead to
Overfrequency adjusts the frequency and voltage value of low frequency and high-frequency signal with voltage regulator module (10)；
Step 3, harmonic signal source are entered by signal tie jumper (5) in rear class power amplifier module (12), to harmonic signal
Carry out power amplification；Harmonic signal acquisition module (8) acquires and handles load (7) both ends harmonic signal voltage value, and by liquid crystal
Display module (9) is shown.
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| CN113676180A (en) * | 2021-08-25 | 2021-11-19 | 温州大学激光与光电智能制造研究院 | Resonance type micro-cantilever sensor intelligent exciting circuit based on DDS and vibration pickup signal amplifying circuit |
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