CN105158574B - Contravariant direct-current spot-welding dynamic electric resistance real-time measuring device and measuring method - Google Patents
Contravariant direct-current spot-welding dynamic electric resistance real-time measuring device and measuring method Download PDFInfo
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Abstract
Contravariant direct-current spot-welding dynamic electric resistance real-time measuring device and measuring method, belong to electronic circuit and field of measuring technique.Solve the problems, such as that existing contravariant direct-current spot-welding dynamic electric resistor e measurement technology accuracy can not be compatible with implementation.Rogowski coil is enclosed on the secondary loop of contravariant direct-current spot welding machine in apparatus of the present invention, two signal output parts of Rogowski coil connect two signal input parts that integration goes back primary circuit respectively, the integration reduction circuit voltage signal output part connection input end of analog signal of embedded microprocessor first, two voltage signal inputs of differential amplifier circuit connect the both ends of the transformer secondary output tap of contravariant direct-current spot welding machine respectively, differential amplifier circuit voltage signal output end connects the second input end of analog signal of embedded microprocessor and the voltage signal inputs of secondary voltage synchronous circuit simultaneously, the timing signal input end of the voltage signal output end connection embedded microprocessor of secondary voltage synchronous circuit.For to dynamic electric resistance real-time measuring in pinpoint welding procedure.
Description
Technical field
The invention belongs to electronic circuit and field of measuring technique.
Background technology
Resistance spot welding is a kind of welding method for being widely used in body of a motor car manufacture, on the vehicle body of a car about
4000-6000 solder joint, the 95% of its welding total amount is accounted for, its quality directly affects the service life of vehicle.Due to automobile
The particularity of Auto-body Spot-welding, postwelding are difficult to remedy, and the sampling observation of conventional postwelding can not meet requirement of the user to body quality.Cause
This, there is an urgent need to find a kind of reliable monitoring method, carries out on-line monitoring to the Auto-body Spot-welding quality of production scene, understands production
The quality of production of product.
Dynamic electric resistor is conventional resistance spot welding quality monitoring signal.Workpiece resistance in heating and fusion process becomes
Change, therefore nugget growing state can be understood by measuring the dynamic electric resistor during spot welding.The dynamic electric resistor proposed at present is surveyed
Amount method mainly for ac spot welding machine, by measure the signals such as primary current, original edge voltage, power-factor angle and calculate so as to
Obtain dynamic electric resistor.However, the special circuit structure of contravariant direct-current spot welding machine causes the signal differences such as its former secondary current, voltage
Larger, above-mentioned dynamic electric resistor measurement scheme is no longer applicable.At present external import controller by measure secondary current and time
Magnitude voltage signals simultaneously calculate virtual value so as to obtain the dynamic electric resistor of contravariant direct-current spot-welding process, but this method is asked in the presence of some
Topic：(1) if installing clamping bleeder mechanism measurement secondary voltage, although measurement result is accurate, folder in electrode welder end
It is larger to hold device volume, lead is long, is unfavorable for field conduct；(2) if secondary voltage is measured in transformer secondary output, although just
Implement in installation, but due to inductance in secondary loop be present, measurement result has perceptual weight, and effective value calculating method is not
Accurately.In some AC resistance spot welding controllers, using the method for voltage at measurement current peak point, perceptual weight is eliminated
Influence, but this method can not be used directly in contravariant direct-current spot-welding.With " industry 4.0 " and " intelligence manufacture 2025 "
The it is proposed of strategy, increasing robot inverse, which will become spot-welding equipment, to be applied in body of a motor car manufacture, therefore, needing one badly
The apparatus and method that kind is accurate, measures contravariant direct-current spot-welding dynamic electric resistor in real time.
The content of the invention
The present invention is can not be simultaneous with implementation in order to solve existing contravariant direct-current spot-welding dynamic electric resistor e measurement technology accuracy
The problem of appearance, the invention provides a kind of contravariant direct-current spot-welding dynamic electric resistance real-time measuring device and measuring method.
Contravariant direct-current spot-welding dynamic electric resistance real-time measuring device, it includes Rogowski coil, integration goes back primary circuit, differential amplification
Circuit, secondary voltage synchronous circuit and embedded microprocessor；
Described Rogowski coil is enclosed on the secondary loop of contravariant direct-current spot welding machine, two signal output parts of Rogowski coil
Connection integration goes back two signal input parts of primary circuit respectively, and the voltage signal output end connection insertion that integration goes back primary circuit declines
First input end of analog signal of processor,
The transformer secondary output that two voltage signal inputs of differential amplifier circuit connect contravariant direct-current spot welding machine respectively is taken out
The both ends of head, the voltage signal output end of differential amplifier circuit connect the second analog signal input of embedded microprocessor simultaneously
End and the voltage signal inputs of secondary voltage synchronous circuit, the voltage signal output end connection insertion of secondary voltage synchronous circuit
The timing signal input end of microsever.
The dynamic electric resistance real-time measuring method realized using described contravariant direct-current spot-welding dynamic electric resistance real-time measuring device,
The detailed process of this method is：
Step 1：After contravariant direct-current spot welding machine is powered, energization welding is carried out, it is inverse using embedded microprocessor timing acquisition
The rising edge of secondary voltage signals on the secondary loop of inversion of direct current mash welder is as temporal reference, and when temporal reference is zero
Carve；
Step 2：Embedded microprocessor has multiple cachings, and embedded microprocessor is begun through to inverse from zero moment
The secondary current and secondary voltage signals of the secondary loop of inversion of direct current mash welder synchronize automatic data collection, and by the data of collection
It is stored in first caching of embedded microprocessor, while the secondary voltage in second caching is calculated using average algorithm
Signal data average value and secondary current signal data average value, then the secondary voltage signals data in second caching are averaged
Value divided by secondary current signal data average value obtain dynamic electric resistor resistance in second caching,
Step 3：When embedded microprocessor captures next temporal reference, embedded microprocessor continues together
The secondary current signal and secondary voltage signals of the secondary loop of step collection contravariant direct-current spot welding machine, and the data of collection are stored in
In second caching of embedded microprocessor, while the secondary voltage signals in first caching are calculated using average algorithm
Statistical average and secondary current signal data average value, then the secondary voltage signals statistical average in first caching is removed
Dynamic electric resistor resistance in first caching is obtained with secondary current signal data average value；
Step 4：Repeat step one to three, until welding terminates, you can obtain the dynamic electric resistor letter in pinpoint welding procedure in real time
Number.
The beneficial effect that the present invention is brought is, contravariant direct-current spot-welding dynamic electric resistance real-time measuring device of the present invention and
Measuring method, the accurate and quick measurement to dynamic electric resistor during contravariant direct-current spot-welding can be achieved, while take into account installation and implement
Property.Secondary current signal is extracted, from transformer secondary output tap extraction secondary voltage signals by Rogowski coil, improves live peace
Fill implementation；The perceptual weight in secondary voltage is effectively reduced using average algorithm, obtains real secondary dynamic electric
Resistance, improve the accuracy of measurement result；Using the high-speed sampling and computing function of embedded microprocessor, obtaining sample rate is
The dynamic electric resistor signal that twice of welding machine reverse frequency, improve the real-time of measurement result；Can finally number be measured to dynamic electric resistor
According to being locally recorded or being communicated upload, the scalability of measurement apparatus is improved.
Brief description of the drawings
Fig. 1 is the principle schematic of contravariant direct-current spot-welding dynamic electric resistance real-time measuring device of the present invention；
Fig. 2 goes back the circuit diagram of primary circuit for the integration described in embodiment four；
Fig. 3 is the circuit diagram of the differential amplifier circuit described in embodiment five；
Fig. 4 is the internal structure schematic diagram of the switch S21 described in embodiment six；
Fig. 5 is the internal structure schematic diagram of the switch S21 described in embodiment seven；
Fig. 6 is the flow chart of the contravariant direct-current spot-welding dynamic electric resistance real-time measuring method described in embodiment nine；
Fig. 7 is the oscillogram of secondary voltage signals；
Fig. 8 is the oscillogram of secondary current signal；
Fig. 9 is the virtual value of secondary voltage signals with the change oscillogram of conduction time；
Figure 10 is the average value of secondary voltage signals with the change oscillogram of conduction time.
Embodiment
Embodiment one：Illustrate present embodiment referring to Fig. 1, the contravariant direct-current spot-welding dynamic described in present embodiment
Resistance real-time measurement apparatus, it includes Rogowski coil 1, integration goes back primary circuit 2, differential amplifier circuit 3, secondary voltage synchronous circuit
4 and embedded microprocessor 5；
Described Rogowski coil 1 is enclosed on the secondary loop 8 of contravariant direct-current spot welding machine, and two signals of Rogowski coil 1 are defeated
Going out end, connection integrates two signal input parts for going back primary circuit 2 respectively, and the voltage signal output end connection that integration goes back primary circuit 2 is embedding
Enter the first input end of analog signal of microsever 5,
Two voltage signal inputs of differential amplifier circuit 3 connect 9 levels of transformer of contravariant direct-current spot welding machine respectively
The both ends of tap, the voltage signal output end of differential amplifier circuit 3 connect the second analog signal of embedded microprocessor 5 simultaneously
The voltage signal inputs of input and secondary voltage synchronous circuit 4, the voltage signal output end of secondary voltage synchronous circuit 4 connect
Connect the timing signal input end of embedded microprocessor 5.
In present embodiment, embedded microprocessor 5 has ADC more than two-way or two-way, all the way or all the way with
On timer, and SPI (Serial Peripheral Interface (SPI)), CAN, USART (universal synchronous/asynchronous serial transceiver) etc. communication
Interface.
Be powered after welding, the rising edge of the timer of embedded microprocessor 5 detection voltage synchronous signal and as
Temporal reference, it is designated as zero moment.The ADC of embedded microprocessor 5 is since zero moment, in voltage synchronous signal
In cycle, gather the instantaneous value of welding current and voltage, and using average algorithm calculate secondary current in a cycle and
Secondary voltage average value, obtain a resistance value.So repeatedly, within the whole weld time, acquisition sample rate is 2fi's
Dynamic electric resistor signal.
Embodiment two：Illustrate present embodiment referring to Fig. 1, present embodiment with described in embodiment one
The difference of contravariant direct-current spot-welding dynamic electric resistance real-time measuring device is that it also includes communication interface circuit 6, communication interface circuit
6 data signal input is connected with the first data signal output of embedded microprocessor 5.
Present embodiment, communication interface circuit 6 are used for device of the present invention with carrying out data interaction between other equipment.
Embodiment three：Illustrate present embodiment referring to Fig. 1, present embodiment with described in embodiment one
The difference of contravariant direct-current spot-welding dynamic electric resistance real-time measuring device is that it also includes data storage circuitry 7, data storage circuitry
7 data signal input is connected with the second data signal output of embedded microprocessor 5.
Present embodiment, data storage circuitry 7 are used for the local record of the measurement data such as Current Voltage.
Embodiment four：Illustrate present embodiment referring to Fig. 2, present embodiment with described in embodiment one
The difference of contravariant direct-current spot-welding dynamic electric resistance real-time measuring device is, described integration, which goes back primary circuit 2, includes resistance R21, electricity
Hinder R22, resistance R23, resistance R24, electric capacity C21, switch S21, operational amplifier OP21 and operational amplifier OP22；
Described resistance R21 both ends are connected with two signal output parts of Rogowski coil 1 respectively, and the one of resistance R21
Termination power,
The resistance R21 other end is connected with resistance R22 one end, the resistance R22 other end while one with resistance R23
End, electric capacity C21 one end, switch S21 one end connect with operational amplifier OP21 inverting input, and resistance R23's is another
End, the electric capacity C21 other end, switch the S21 other end, operational amplifier OP21 signal output part and operational amplifier OP22
The connection of in-phase signal input, operational amplifier OP22 inversion signal input is connected with its signal output part, and computing is put
The voltage signal output end that big device OP22 signal output part goes back primary circuit 2 as integration connects the of embedded microprocessor 5
One input end of analog signal,
A resistance R24 termination power, the resistance R24 other end and operational amplifier OP21 in-phase signal input
Connection.
In present embodiment, a kind of concrete structure that integration goes back primary circuit 2 is given, the structure can utilize the product of circuit
The intrinsic current differential signal by Rogowski coil output carries out integration reduction, obtains and the proportional voltage of secondary current size
Signal.
In order to reduce integrator drift and capacitance leakage error, resistance R22 and resistance R23 value should meet following relation：
Wherein, R22 is resistance R22 resistance, and R23 is resistance R23 resistance.
It is powered before welding, switch S21 is off；It is powered after welding, switch S21 closures, carries out current differential letter
Number integration reduction.
Embodiment five：Illustrate present embodiment referring to Fig. 3, present embodiment with described in embodiment one
The difference of contravariant direct-current spot-welding dynamic electric resistance real-time measuring device is that described differential amplifier circuit 3 includes resistance R31, electricity
Hinder R32, resistance R33, resistance R34, resistance R35, resistance R36, electric capacity C31, operational amplifier OP31, operational amplifier OP32 and
Operational amplifier OP33；
Described operational amplifier OP31 in-phase signal input and operational amplifier OP32 in-phase signal input
The both ends with the secondary tap of transformer 9 of contravariant direct-current spot welding machine are connected respectively,
Operational amplifier OP31 inversion signal input is connected with one end of its signal output part and resistance R31, resistance
The R31 other end is connected with resistance R33 one end and electric capacity C31 one end simultaneously, the resistance R33 other end while and computing
Amplifier OP33 inverting input connects with resistance R35 one end, the resistance R35 other end and operational amplifier OP33 letter
The connection of number output end, the voltage signal output end of operational amplifier OP33 signal output part as differential amplifier circuit 3,
Operational amplifier OP32 inversion signal input is connected with one end of its signal output part and resistance R32, resistance
The R32 other end is connected with the electric capacity C31 other end and one end of resistance R34 simultaneously, the other end of resistance R34 while and computing
Amplifier OP33 in-phase signal input connects with resistance R36 one end, resistance R36 another termination power.
In present embodiment, a kind of concrete structure of differential amplifier circuit 3 is given, the structure can utilize operation amplifier
The same phase follower that device OP31 and operational amplifier OP42 are formed improves the input impedance of circuit, using resistance R31, resistance R32,
The interference of high-frequency noise is reduced with the low-pass filter circuit that electric capacity C31 is formed, utilizes resistance R33, resistance R34, resistance R35, electricity
The amplifying circuit that resistance R36 and operational amplifier OP33 is formed is amplified or decayed to signal, so as to obtain with appropriate amplitude
Secondary voltage signals.Multiplication factor G is：
Wherein, G is multiplication factor, and R33 is resistance R33 resistance, and R34 is the resistance of resistance R34, and R35 is resistance R35's
Resistance, R36 are resistance R36 resistance.
Meanwhile in order to ensure appropriate multiplication factor,
Wherein, UsFor the amplitude of secondary voltage signals, VCC is power supply cathode voltage.
In order to avoid the high-frequency noise in signal has an impact to output signal, resistance R31, resistance R32 and electric capacity C31's
Value should meet following relation：
Wherein, fiThe reverse frequency of mash welder is represented, R31 is R31 resistance, and R32 is R32 resistance, and C31 is electric capacity
C31 capacitance.
Embodiment six：Illustrate present embodiment referring to Fig. 4, present embodiment with described in embodiment four
The difference of contravariant direct-current spot-welding dynamic electric resistance real-time measuring device is that described switch S21 includes metal-oxide half field effect transistor
D41 and resistance R41；
Resistance R41 one end connection positive source,
Resistance R41 other end connection metal-oxide half field effect transistor D41 grid, and simultaneously as with embedded microprocessor
The control signal input that device 5 connects,
Metal-oxide half field effect transistor D41 source electrode and drain electrode are respectively as the both ends for switching S21.
Embodiment seven：Illustrate present embodiment referring to Fig. 5, present embodiment with described in embodiment four
The difference of contravariant direct-current spot-welding dynamic electric resistance real-time measuring device is that described switch S21 includes：Optocoupler D51 and resistance
R51；
Resistance R51 one end connection positive source,
The positive pole of light emitting diode in resistance R51 other end connection optocoupler D51, and simultaneously as with embedded microprocessor
The control signal input that device 5 connects, the negative pole ground connection of light emitting diode in optocoupler D51, the collection of phototriode in optocoupler D51
Electrode and emitter stage are respectively as the both ends for switching S21.
Embodiment eight：Illustrate present embodiment referring to Fig. 1, present embodiment with described in embodiment one
The difference of contravariant direct-current spot-welding dynamic electric resistance real-time measuring device is, described embedded microprocessor 5 using single-chip microcomputer,
DSP Processor or FPGA are realized.
In present embodiment, embedded microprocessor 5 has ADC more than two-way or two-way, all the way or all the way with
On timer, and SPI (Serial Peripheral Interface (SPI)), CAN, USART (universal synchronous/asynchronous serial transceiver) etc. communication
Interface.
Embodiment nine：Illustrate present embodiment referring to Fig. 6, using the inversion direct current described in embodiment one
The dynamic electric resistance real-time measuring method that spot-welding dynamic electric resistance real-time measuring device is realized, the detailed process of this method are：
Step 1：After contravariant direct-current spot welding machine is powered, energization welding is carried out, utilizes the timing acquisition of embedded microprocessor 5
The rising edge of secondary voltage signals on the secondary loop 8 of contravariant direct-current spot welding machine is as temporal reference, and temporal reference is
Zero moment；
Step 2：Embedded microprocessor 5 has multiple cachings, and it is right to begin through embedded microprocessor 5 from zero moment
The secondary current and secondary voltage signals of the secondary loop 8 of contravariant direct-current spot welding machine synchronize automatic data collection, and by collection
In first caching of data deposit embedded microprocessor 5, while time in second caching is calculated using average algorithm
Magnitude voltage signals statistical average and secondary current signal data average value, then by second caching in secondary voltage signals number
Dynamic electric resistor resistance in second caching is obtained according to average value divided by secondary current signal data average value,
Step 3：When embedded microprocessor 5 captures next temporal reference, embedded microprocessor 5 continues
The secondary current signal and secondary voltage signals of the secondary loop 8 of synchronous acquisition contravariant direct-current spot welding machine, and by the data of collection
It is stored in second caching of embedded microprocessor 5, while the secondary electrical in first caching is calculated using average algorithm
Signal data average value and secondary current signal data average value are pressed, then the secondary voltage signals data in first caching are put down
Average divided by secondary current signal data average value obtain dynamic electric resistor resistance in first caching；
Step 4：Repeat step one to three, until welding terminates, you can obtain the dynamic electric resistor letter in pinpoint welding procedure in real time
Number.
In present embodiment, contravariant direct-current spot-welding dynamic electric resistance real-time measuring device of the present invention is arranged on inversion
Frequency is fiContravariant direct-current spot welding machine on.Rogowski coil 1 and integration go back primary circuit 2 and are used to measure secondary current, and output has
Frequency is 2fiThe long pulse signal of ripple；Differential amplifier circuit 3 is used to measure secondary voltage, output frequency 2fiSquare wave letter
Number；It is 2f that secondary voltage synchronous circuit 4, which exports the frequency synchronous with secondary voltage signals,iPulse signal, as sampling and meter
The temporal reference of calculation, it is designated as voltage synchronous signal；Two ADCs of embedded microprocessor 5 are used for electric current and voltage transient
The sampling of value；The timer of embedded microprocessor 5 is used for the sequential for controlling sampling and calculating.
Embodiment ten：Illustrate present embodiment, present embodiment and embodiment nine referring to Fig. 6 to Figure 10
The difference of the described dynamic electric resistance real-time measuring method realized using contravariant direct-current spot-welding dynamic electric resistance real-time measuring device is existed
In the calculation formula of the average algorithm in described step two and step 3 is：
N represents the number of samples in an inversion cycle, IiFor the measurement instantaneous value of secondary current, UiFor secondary voltage
Measure instantaneous value, IAVGFor the secondary current average value in an inversion cycle, UAVGFor the secondary voltage in an inversion cycle
Average value, i are positive integer；
The sampling rate of embedded microprocessor 5 is, it is known that N can be calculated by equation below：
Wherein, fiRepresent the reverse frequency of mash welder, fsRepresent sample frequency.
For the confirmatory experiment effect of the present invention：
It is following to test for verifying contravariant direct-current spot-welding dynamic electric resistance real-time measuring device of the present invention and measurement side
Method, can be with the dynamic electric resistor signal of accurate measurement contravariant direct-current spot-welding, while taking into account installation implementation.
According to Ohm's law, in order to obtain the dynamic electric resistor between two electrode end surfaces, it is necessary between accurate measurement electrode end surface
Voltage.However, the method reliability that voltage measurement is directly carried out in electrode tip conducting wire is low, it is easy exposed to outer wire
Fracture, be also subject to the destruction of spatter, be not suitable for scene batch and use.And measured from transformer secondary output tap extraction wire
During secondary voltage, the presence of the inductance of secondary loop can cause significant impact to measurement result, and secondary voltage formula is as follows
Wherein, U represents secondary voltage size, and I is secondary current size, RsFor the resistance of soldering turret secondary loop, LsFor secondary
Loop inductance.
It was found from formula (1), secondary voltage U is made up of two parts, respectively resistive component and perceptual weight.Only work as secondary
The inductance L in loopSFor 0 when, secondary voltage U divided by electric current I result are only the resistance R of secondary loops。
According to the equivalent-circuit model of electric resistance welding secondary circuit, secondary voltage can be tried to achieve by equation below：
Wherein, U (t0+ t) represent secondary voltage in t0The size of+t, t0For initial time, t is apart from initial time
Time, UsFor the amplitude of secondary voltage signals, n is some positive integer, fiThe reverse frequency of mash welder is represented, s represents voltage letter
Number dutycycle size.
Under permanent duty cycle condition, secondary current can be tried to achieve by equation below：
Wherein, I (t0+ t) for secondary current in t0The size of+t, n are some positive integer.
Following value is carried out according to above-mentioned model and formula：Us=10V, s=20%, fi=1kHz, Rs=500 μ Ω and
Ls=0.5 μ H, draw out inverse spot-welding machine secondary voltage and current signal, as shown in Figure 7 and Figure 8.
Wherein Fig. 7 is secondary voltage signals, and Fig. 8 is secondary current signal.
Fig. 9 is the virtual value of secondary voltage signals with the changing rule of conduction time.Within each inversion cycle, virtual value
Formula is as follows：
Wherein, RdFor the dynamic electric resistor calculated value in an inversion cycle.
It can be found that the virtual value of perceptual weight is larger in secondary voltage measured value and is just, to cause secondary electrical from Fig. 9
Pressure measured value is significantly greater than resistive component, illustrates more error be present when calculating dynamic electric resistor using rms algorithm.
Figure 10 is the average value of voltage signal with the changing rule of conduction time.It can be found that in secondary voltage measured value
The average value of perceptual weight reduces rapidly；After a short period of time, the average value of perceptual weight is approximately 0, and secondary voltage average value is complete
It is made up of resistive component, illustrates effectively reduce perceptual weight when calculating dynamic electric resistor using average algorithm, improve dynamic electric
Hinder the accuracy of measurement.
Workpiece is 0.7mm+0.7mm galvanized steels between the enterprising Mobile state resistance measurement experiment of contravariant direct-current spot welding machine, electrode
Plate, electrode force size are 2.5kN, and electrical current size is 10kA, conduction time 200ms, is surveyed using device of the present invention
The Current Voltage and dynamic electric resistor signal of amount, it can be found that secondary loop dynamic electric resistor signal be powered start 50ms and
There is steep drop phenomenon in 130ms, illustrate that early stage in pinpoint welding procedure be present splashes and later stage splashing defect, shows of the present invention
Contravariant direct-current spot-welding dynamic electric resistance real-time measuring device has stronger real-time and accuracy with method, can effectively measure inverse
The dynamic electric resistor signal become during spot welding.
Claims (9)
1. contravariant direct-current spot-welding dynamic electric resistance real-time measuring device, it includes Rogowski coil (1), integration goes back primary circuit (2), difference
Amplifying circuit (3), secondary voltage synchronous circuit (4) and embedded microprocessor (5)；
Described Rogowski coil (1) is enclosed on the secondary loop (8) of contravariant direct-current spot welding machine, two signals of Rogowski coil (1)
Output end connects two signal input parts that integration goes back primary circuit (2) respectively, and integration goes back the voltage signal output end of primary circuit (2)
The first input end of analog signal of embedded microprocessor (5) is connected,
The transformer (9) that two voltage signal inputs of differential amplifier circuit (3) connect contravariant direct-current spot welding machine respectively is secondary
The both ends of tap, the voltage signal output end of differential amplifier circuit (3) connect the second simulation of embedded microprocessor (5) simultaneously
The voltage signal inputs of signal input part and secondary voltage synchronous circuit (4), the voltage signal of secondary voltage synchronous circuit (4)
The timing signal input end of output end connection embedded microprocessor (5)；
Characterized in that, described integration, which goes back primary circuit (2), includes resistance R21, resistance R22, resistance R23, resistance R24, electric capacity
C21, switch S21, operational amplifier OP21 and operational amplifier OP22；
Described resistance R21 both ends are connected with two signal output parts of Rogowski coil (1) respectively, and resistance R21 one end
With connecing power supply,
The resistance R21 other end is connected with resistance R22 one end, the resistance R22 other end while one end with resistance R23, electricity
The one end for holding C21, the one end for switching S21 connect with operational amplifier OP21 inverting input, resistance the R23 other end, electricity
Hold the same of the C21 other end, the other end for switching S21, operational amplifier OP21 signal output part and operational amplifier OP22
Phase signals input is connected, and operational amplifier OP22 inversion signal input is connected with its signal output part, operational amplifier
OP22 signal output part goes back the of the voltage signal output end connection embedded microprocessor (5) of primary circuit (2) as integration
One input end of analog signal,
A resistance R24 termination power, the resistance R24 other end connects with operational amplifier OP21 in-phase signal input
Connect.
2. contravariant direct-current spot-welding dynamic electric resistance real-time measuring device according to claim 1, it is characterised in that it also includes
Communication interface circuit (6), the data signal input of communication interface circuit (6) and the first data of embedded microprocessor (5)
Signal output part connects.
3. contravariant direct-current spot-welding dynamic electric resistance real-time measuring device according to claim 2, it is characterised in that it also includes
Data storage circuitry (7), the data signal input of data storage circuitry (7) and the second data of embedded microprocessor (5)
Signal output part connects.
4. contravariant direct-current spot-welding dynamic electric resistance real-time measuring device according to claim 1, it is characterised in that described difference
Amplifying circuit (3) is divided to include resistance R31, resistance R32, resistance R33, resistance R34, resistance R35, resistance R36, electric capacity C31, computing
Amplifier OP31, operational amplifier OP32 and operational amplifier OP33；
Described operational amplifier OP31 in-phase signal input and operational amplifier OP32 in-phase signal input difference
It is connected with the both ends of transformer (9) secondary tap of contravariant direct-current spot welding machine,
Operational amplifier OP31 inversion signal input is connected with one end of its signal output part and resistance R31, resistance R31's
The other end is connected with resistance R33 one end and electric capacity C31 one end simultaneously, the resistance R33 other end while and operation amplifier
Device OP33 inverting input connects with resistance R35 one end, and the signal of resistance the R35 other end and operational amplifier OP33 is defeated
Go out end connection, the voltage signal output end of operational amplifier OP33 signal output part as differential amplifier circuit (3),
Operational amplifier OP32 inversion signal input is connected with one end of its signal output part and resistance R32, resistance R32's
The other end is connected with the electric capacity C31 other end and one end of resistance R34 simultaneously, the other end of resistance R34 while and operation amplifier
Device OP33 in-phase signal input connects with resistance R36 one end, resistance R36 another termination power.
5. contravariant direct-current spot-welding dynamic electric resistance real-time measuring device according to claim 1, it is characterised in that described opens
Closing S21 includes metal-oxide half field effect transistor D41 and resistance R41；
Resistance R41 one end connection positive source,
Resistance R41 other end connection metal-oxide half field effect transistor D41 grid, and simultaneously as with embedded microprocessor
(5) control signal input of connection,
Metal-oxide half field effect transistor D41 source electrode and drain electrode are respectively as the both ends for switching S21.
6. contravariant direct-current spot-welding dynamic electric resistance real-time measuring device according to claim 1, it is characterised in that described opens
Closing S21 includes：Optocoupler D51 and resistance R51；
Resistance R51 one end connection positive source,
The positive pole of light emitting diode in resistance R51 other end connection optocoupler D51, and simultaneously as with embedded microprocessor
(5) control signal input of connection, the negative pole ground connection of light emitting diode in optocoupler D51, the colelctor electrode of triode in optocoupler D51
Both ends with emitter stage respectively as switch S21.
7. contravariant direct-current spot-welding dynamic electric resistance real-time measuring device according to claim 1, it is characterised in that described is embedding
Enter microsever (5) to realize using single-chip microcomputer, DSP Processor or FPGA.
8. the dynamic electric resistor realized using the contravariant direct-current spot-welding dynamic electric resistance real-time measuring device described in claim 1 is surveyed in real time
Amount method, it is characterised in that the detailed process of this method is：
Step 1：After contravariant direct-current spot welding machine is powered, energization welding is carried out, it is inverse using embedded microprocessor (5) timing acquisition
The rising edge of secondary voltage signals on the secondary loop (8) of inversion of direct current mash welder is as temporal reference, and temporal reference is
Zero moment；
Step 2：Embedded microprocessor (5) has multiple cachings, and it is right to begin through embedded microprocessor (5) from zero moment
The secondary current and secondary voltage signals of the secondary loop (8) of contravariant direct-current spot welding machine synchronize automatic data collection, and will collection
Data deposit first of (5) caching of embedded microprocessor in, while calculated using average algorithm in second caching
Secondary voltage signals statistical average and secondary current signal data average value, then by second caching in secondary voltage believe
Number average value divided by secondary current signal data average value obtain dynamic electric resistor resistance in second caching,
Step 3：When embedded microprocessor (5) captures next temporal reference, embedded microprocessor (5) continues
The secondary current signal and secondary voltage signals of the secondary loop (8) of synchronous acquisition contravariant direct-current spot welding machine, and by the number of collection
In being cached according to second of deposit embedded microprocessor (5), while time in first caching is calculated using average algorithm
Magnitude voltage signals statistical average and secondary current signal data average value, then by first caching in secondary voltage signals number
Dynamic electric resistor resistance in first caching is obtained according to average value divided by secondary current signal data average value；
Step 4：Repeat step one to three, until welding terminates, you can obtain the dynamic electric resistor signal in pinpoint welding procedure in real time.
9. the dynamic electric resistor according to claim 8 realized using contravariant direct-current spot-welding dynamic electric resistance real-time measuring device is real
When measuring method, it is characterised in that the calculation formula of the average algorithm in described step two and step 3 is：
<mrow>
<mfenced open = "{" close = "">
<mtable>
<mtr>
<mtd>
<mrow>
<msub>
<mi>I</mi>
<mrow>
<mi>A</mi>
<mi>V</mi>
<mi>G</mi>
</mrow>
</msub>
<mo>=</mo>
<mfrac>
<mn>1</mn>
<mi>N</mi>
</mfrac>
<munderover>
<mo>&Sigma;</mo>
<mrow>
<mi>i</mi>
<mo>=</mo>
<mn>1</mn>
</mrow>
<mi>N</mi>
</munderover>
<msub>
<mi>I</mi>
<mi>i</mi>
</msub>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<msub>
<mi>U</mi>
<mrow>
<mi>A</mi>
<mi>V</mi>
<mi>G</mi>
</mrow>
</msub>
<mo>=</mo>
<mfrac>
<mn>1</mn>
<mi>N</mi>
</mfrac>
<munderover>
<mo>&Sigma;</mo>
<mrow>
<mi>i</mi>
<mo>=</mo>
<mn>1</mn>
</mrow>
<mi>N</mi>
</munderover>
<msub>
<mi>U</mi>
<mi>i</mi>
</msub>
</mrow>
</mtd>
</mtr>
</mtable>
</mfenced>
<mo>,</mo>
</mrow>
N represents the number of samples in an inversion cycle, IiFor the measurement instantaneous value of secondary current, UiFor the measurement of secondary voltage
Instantaneous value, IAVGFor the secondary current average value in an inversion cycle, UAVGIt is averaged for the secondary voltage in an inversion cycle
Value, i is positive integer；
When known to the sampling rate of embedded microprocessor (5), N can be calculated by equation below：
<mrow>
<mi>N</mi>
<mo>=</mo>
<mfrac>
<msub>
<mi>f</mi>
<mi>s</mi>
</msub>
<msub>
<mi>f</mi>
<mi>i</mi>
</msub>
</mfrac>
<mo>,</mo>
</mrow>
Wherein, fiRepresent the reverse frequency of mash welder, fsRepresent sample frequency.
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| CN108941873B (en) * | 2018-05-21 | 2024-04-19 | 上海圣缑电磁设备有限公司 | Resistance welding circuit and dynamic measurement and control method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101149405A (en) * | 2007-09-20 | 2008-03-26 | 上海交通大学 | AC spot-welding dynamic electric resistance real-time measuring device and method |
| CN101733540A (en) * | 2009-11-23 | 2010-06-16 | 上海交通大学 | Method for acquiring values of trigger angle and extinguishing angle in real time in alternating current resistor spot welding |
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| JP3817537B2 (en) * | 2003-10-02 | 2006-09-06 | 学校法人 中村産業学園 | Ultra high resistance measuring device and ultra high resistance measuring method |
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| CN101149405A (en) * | 2007-09-20 | 2008-03-26 | 上海交通大学 | AC spot-welding dynamic electric resistance real-time measuring device and method |
| CN101733540A (en) * | 2009-11-23 | 2010-06-16 | 上海交通大学 | Method for acquiring values of trigger angle and extinguishing angle in real time in alternating current resistor spot welding |
Non-Patent Citations (2)
| Title |
|---|
| DZ-47触头电阻焊;朱世良等;《焊接学报》;20141231;第35卷(第12期);第67-71页 * |
| 电阻点焊过程中动态电阻的变化规律;王亚荣等;《电焊机》;20060228;第36卷(第2期);第42-44页 * |
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