CN106862737A - Output overcurrent protection control circuit and the method for a kind of plasma cutting power supply - Google Patents
Output overcurrent protection control circuit and the method for a kind of plasma cutting power supply Download PDFInfo
- Publication number
- CN106862737A CN106862737A CN201710165104.1A CN201710165104A CN106862737A CN 106862737 A CN106862737 A CN 106862737A CN 201710165104 A CN201710165104 A CN 201710165104A CN 106862737 A CN106862737 A CN 106862737A
- Authority
- CN
- China
- Prior art keywords
- module
- output
- current
- input
- protection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K10/00—Welding or cutting by means of a plasma
- B23K10/006—Control circuits therefor
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- Mechanical Engineering (AREA)
- Plasma Technology (AREA)
Abstract
The invention discloses output overcurrent protection control circuit and the method for a kind of plasma cutting power supply, output overcurrent protection control circuit includes：It is input into main power model, output inductor, high-frequency model, output detection module and control module；The input of output inductor is connected to the first output end for being input into main power model, the input of high-frequency model is connected to the second output end for being input into main power model, the first input end for exporting detection module is connected to the output end of output inductor, the second input for exporting detection module is connected to the output end of high-frequency model, the 3rd output end for exporting detection module is connected to the first input end of control module, the 4th output end for exporting detection module is connected to the second input of control module, the output end of control module is connected to the control end for being input into main power model.The present invention had not only been avoided that plasma cutting power supply breaks down because output current is excessive and had been avoided that production efficiency attenuating caused by protection false triggering.
Description
Technical field
The invention belongs to Arc Welding Power technical field, more particularly, to a kind of output overcurrent of plasma cutting power supply
Protection control circuit and method.
Background technology
Plasma cutting power supply is the important component in welding equipment, is had to the development of arc welding equipment industry important
Meaning, the development with National Industrial is closely related.Plasma cutting power supply be a kind of output of low-voltage, high-current, dynamic response it is fast,
Reliability requirement special power supply high.The main circuit of existing plasma cutting power supply DC converting part generally uses phase-shifting full-bridge
Topology, realizes isolating for power network and late-class circuit, it is ensured that the safety of cutting operation.Plasma cutting power supply is difficult in normal work
Exempt to cause to export electricity due to reasons such as the contact starting the arc under misoperation, workpiece surface out-of-flatness, contactless striking mode
Stream failure.To ensure the safe and reliable work of plasma cutting power supply, it is necessary to quick when there is output overcurrent fault, accurate
Ground responds to failure.
Believed by sampled output current using the method for current instantaneous value protection mostly in existing plasma cutting power supply
Number, after then comparing with the current protection limit value of setting via digital signal processor (DSP), make protection and judge, Ran Houfeng
Lock drive signal, makes plasma cutting power supply be stopped.
As plasma cutting power supply switching device frequency is improved constantly, the method effect of above-mentioned current instantaneous value protection by
Gradually it is weakened.On the one hand, because switching frequency is improved, the outputting inductance inductance value of phase-shifting full-bridge part is set in plasma cutting power supply
Count smaller, this is advantageously implemented the high power density of power supply, but also cause that inductance becomes to the rejection ability of curent change simultaneously
It is weak.When load impedance is undergone mutation, curent change will more acutely, in the case of uncontrolled, it is easier to occur defeated
Go out overcurrent fault.On the other hand, while switching frequency is improved, due to hardware limitation or for cost consideration, system control
Frequency processed there is no lifting or lifting not as switching frequency so that switch motion increased frequency in unit controlling cycle, control difficulty
Increase.
In these cases, if the protection limit value of current instantaneous value protection sets excessive, easily there is a upper controlling cycle
Not yet detect overcurrent, and next controlling cycle has exceeded the current stress of device when detecting overcurrent, it is impossible to play guarantor
Shield is acted on, and influences the safe and reliable work of plasma cutting power supply；If the protection limit value of current instantaneous value protection sets too small, can
Can in normal work, output current slightly has overshoot under the adjustment effect of controller, more than current protection limit value, occur to protect by mistake
Phenomenon, greatly reduces the production efficiency of plasma cutting power supply.
The content of the invention
For the defect of prior art, it is an object of the invention to provide a kind of output overcurrent guarantor of plasma cutting power supply
Shield control method, it is intended to solve the problems, such as that existing output current guard method cannot correctly and efficiently trigger protection.
The invention provides a kind of output overcurrent protection control circuit of plasma cutting power supply, including：It is input into main power
Module, output inductor, high-frequency model, output detection module and control module；The input of output inductor is connected to
The first output end of main power model is input into, the input of high-frequency model is connected to the second output end for being input into main power model,
The first input end for exporting detection module is connected to the output end of output inductor, and the second input for exporting detection module connects
It is connected to the output end of high-frequency model, exporting the first output end of detection module is used to being connected to tungsten electrode, the of output detection module
Two output ends are used to be connected to for being connected to workpiece, and the 3rd output end of the output detection module is connected to the control mould
The first input end of block, the 4th output end of the output detection module is connected to the second input of the control module, institute
The output end for stating control module is connected to the control end of the main power model of input.
Further, during work, the electric energy of input is converted to low-voltage direct-current electric energy by the main power input module,
And after being filtered through the output inductor and the high-frequency model, by the output detection module to output voltage and output electricity
Stream is detected that final output to tungsten electrode, cutting torch and workpiece carry out plasma cut work；The control module is according to described defeated
The output voltage signal and output current signal for going out detection module detection export drive for controlling the main power input module
Dynamic signal；When there is output overcurrent, the drive signal controls the main power input module from service, so as to realize
Stream protection.
Further, output detection module includes：Current detection module and voltage detection module；Current detection module
Input is examined as the first input end for exporting detection module, the first output end of current detection module as the output
The first output end of module is surveyed, the second output end of current detection module is used as the 3rd output end for exporting detection module；
The first input end of voltage detection module is connected with the first output end of output electric current measure module, and the second of voltage detection module
Input as output detection module the second input, while also serve as it is described output detection module the second output end, electricity
The first output end of detection module is pressed as the 4th output end of the output detection module.
Further, control module includes：Drive module, phase shift computing module, data acquisition module, logic synthesis mould
Block, protection recovery timer, current slope protection module, comparison module, current slope computing module and the second comparison module；Drive
The first input end of dynamic model block is connected with the first output end of integrated logic module, the second input and the phase shift meter of drive module
The first output end for calculating module is connected, the first output end of drive module as control module the first output end；Phase shift is calculated
The first input end that the first input end of module is connected as control module with the first input end of data acquisition module, phase shift meter
The second input of module is calculated as the second input of control module, first output end and drive module of phase shift computing module
The second input be connected；The first input end of data acquisition module is connected as control with the first input end of phase shift computing module
The first input end of molding block, the first output end of data acquisition module and the first input end phase of current slope computing module
Even, the second output end of data acquisition module is connected with the first input end of the second comparison module；The first of logic synthesis module
First output end of input current slope protection module is connected, and the second input and the protection of logic synthesis module recover timing
First output end of device is connected, the 3rd input of logic synthesis module and the first output end phase of second comparison module
Even；The first input end of recovery timer is protected to be connected with the first output end of the current slope protection module, the protection
First output end of recovery timer is connected with the second input of the logic synthesis module；The of current slope protection module
One input is connected with the first output end of the comparison module, the first output end of current slope protection module and logic synthesis
The first input end of module is connected, while the first output end of current slope protection module is defeated with the first of protection recovery timer
Enter end to be connected；The first input end of comparison module is connected with the first output end of current slope computing module, and the of comparison module
Two inputs are that slope protects limit value km, the first output end of the comparison module and the first of the current slope protection module
Input is connected；The first input end of current slope computing module is connected with the first output end of the data acquisition module, electricity
The first output end for flowing slope computing module is connected with the first input end of the comparison module；The first of second comparison module is defeated
Enter end to be connected with the second output end of data acquisition module, the second input of the second comparison module is protected for current instantaneous value and limited
Value Ip；Data acquisition module is used to gather the output current value I of current control periodk, a upper controlling cycle output current value
Ik-1；Current slope computing module is used for the output current value I according to current control periodk, a upper controlling cycle output current
Value Ik-1Calculate the current slope k of current control period；The comparison module is used for the current slope k according to current control period
Current slope protection limit value kp computings with setting obtain logic comparative result；Overcurrent protection module compares knot according to the logic
Whether fruit sends the signal protected；Protection recovery timer determines whether to start according to the current protection signal of overcurrent protection module
Protection recover timing, when protect recovery timer receive current protection signal when reset timing, when protection recovery timer not
Start timing when receiving current protection signal, protection recovery timing threshold value a is reached when current slope protection recovers clocking value N
When, send protection and recover signal；Logic synthesis module is used to carry out logic with protection recovery signal to current slope protection signal
Comprehensive descision, when current slope protection signal is invalid and protection recovery signal is effective, driving locking signal is not sent, is otherwise sent out
Go out to drive locking signal；The drive module is used for sending or blocking for driving, when drive module receives logic synthesis module
During the driving locking signal for sending, drive module block drives, and does not send drive signal, is otherwise calculated according to phase shift computing module
The phase shifting angle for obtaining generates corresponding drive signal and sends drive signal to the control end of the main power model of input, drives
The dynamic main power model work of the input.
A kind of output overcurrent present invention also offers plasma cutting power supply protects control method, comprises the steps：
(1) the output current value I of current control period is gatheredkWith the output current value I of a upper controlling cyclek-1, and according to
Formula k=Ik-Ik-1Calculate the current slope k of current control period；
(2) judge whether the output current value of current control period protects limit value Ip more than output current, if so, then carrying out
Block is driven, makes phase-shifting full-bridge module from service；If it is not, being then transferred to step (3)；
(3) judge whether the current slope k of current control period protects limit value kp more than current slope, if so, then carrying out
Block is driven, makes phase-shifting full-bridge module from service；If it is not, being then transferred to step (4)；
(4) judge that current slope protection recovers whether clocking value recovers timing threshold value more than protection, if so, then recovering to drive
It is dynamic, according to the phase shift signal output drive signal that phase shift computing module is obtained, and N=0；If it is not, being then driven block, make shifting
Phase full-bridge modules are stopped, and N=N+1.
In embodiments of the present invention, current slope protection limit value kp allows maximum current climbing to determine according to system, and one
As it is determined that allow maximum current climbing after take certain allowance, be taken as allow maximum current climbing 0.85-0.95.Electric current
Current slope change when slope protects limit value with outputting inductance inductance value, switching frequency, control frequency and normal work is relevant.It is defeated
Go out that inductance inductance value is bigger, current slope when breaking down is smaller；Under same switch frequency, control frequency is higher, required setting
Current slope protection limit value can be bigger；Under identical control frequency, switching frequency is higher, the current slope protection of required setting
Limit value is smaller；And current slope value of the current slope protection limit value for setting when have to be larger than normal work, reduce as far as possible and protect by mistake
Shield probability.
In embodiments of the present invention, current instantaneous value protection limit value Ip should be true according to the maximum allowable operating current point of system
It is fixed, typically it is determined that take certain allowance after maximum allowable operating current, it is taken as the 0.85-0.95 of maximum allowable operating current.This
The protection control method being combined with current slope protection is protected in invention using current instantaneous value, and system is ensured in current slope protection
On the premise of system safety, can suitably relax current instantaneous value protection limit value.Protection recovers timing threshold value should be according to electricity after protection
Stream recovery time determines that generally 10-100 controlling cycle, i.e., described protection recovers timing threshold value a for 10-100.Protection is extensive
The selection of multiple timing threshold value is relevant with outputting inductance, and outputting inductance is bigger, and electric current is got over the time required to dropping to zero after protecting
Long, the timing threshold value of required setting is more long.
By the contemplated above technical scheme of the present invention, compared with prior art, due to using current slope to judge
Condition, it is possible to being more prone to anticipation goes out output current overcurrent fault, it is ensured that the safe and reliable work of plasma cutting power supply
Make；Meanwhile, the protection limit value of current instantaneous value protection can be suitably increased with reference to current instantaneous value protection, reduce the general of protection by mistake
Rate, improve production efficiency.Further, since the output overcurrent protection that the reason such as maloperation, workpiece surface out-of-flatness is caused, without
Restarting machine, only just need to can re-start cutting work by the wait of several controlling cycles, and production effect is greatly improved
Rate.
Brief description of the drawings
Fig. 1 is the modular structure schematic diagram of plasma cutting power supply provided in an embodiment of the present invention；
Fig. 2 is a kind of realization of the output overcurrent protection control method of plasma cutting power supply provided in an embodiment of the present invention
Flow chart；
The theoretical critical oscillogram of trigger slope protection when Fig. 3 is using guard method of the present invention；
Fig. 4 triggers the theoretical critical oscillogram of instantaneous value protection when being using guard method of the present invention；
The emulation key waveforms figure of trigger slope protection when Fig. 5 is using guard method of the present invention；
Fig. 6 triggers the emulation key waveforms figure of instantaneous value protection when being using guard method of the present invention.
Wherein, SC is input ac power, and REC is high-frequency rectification module, and PSFB is phase-shifting full-bridge module, and DCL is output
Filter inductance, CD is current detection module, and VD is voltage detection module, and HFM is high-frequency model, and DRV is drive module, and PSCM is
Phase shift computing module, LSM is logic synthesis module, and PRT recovers timer for protection, and CSPM is current slope protection module, CM
It is comparison module, CSCM is current slope computing module, and DCM is data acquisition module, and Drv is drive signal, and Pss is phase shift control
Signal processed, to drive locking signal, Prs to recover signal for protection, Cps is current slope protection signal to Dbs, and kp is current slope
Protection limit value, k is current control period current slope, and Io is output current value, IkIt is the output current value of current control period,
Ik-1It is the output current value of a upper controlling cycle, Ip is that output current protects limit value, and Imax is maximum allowable operating current point,
Vo is output voltage values, and Tc is controlling cycle, and Ts is switch periods, and N recovers clocking value for protection, and a recovers timing threshold for protection
Value, kmax is permission maximum current climbing.
1 is the main power model of input, and 2 is output inductor, and 3 is high-frequency model, and 4 is output detection module, and 5 is control
Module, 6 is tungsten electrode, and 7 is cutting torch, and 8 is workpiece, and 10 is input ac power, and 11 is high-frequency rectification module, and 12 is phase-shifting full-bridge mould
Block, 40 is current detection module, and 41 is voltage detection module, and 50 is drive module, and 51 is phase shift computing module, and 52 adopt for data
Collection module, 53 is logic synthesis module, and 54 is protection recovery timer, and 55 is current slope protection module, and 56 is comparison module,
57 is current slope computing module, and 58 is the second comparison module.
Specific embodiment
In order to make the purpose , technical scheme and advantage of the present invention be clearer, it is right below in conjunction with drawings and Examples
The present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, and
It is not used in the restriction present invention.
A kind of output overcurrent the invention provides plasma cutting power supply protects control method, solves existing output electricity
Stream guard method cannot correctly and efficiently trigger protection problem, such as in normal work mistiming trigger protection or exporting
Cannot trigger protection etc. during over current fault.
The present invention relates to a kind of output overcurrent protection control circuit of plasma cutting power supply, including it is input into main power model
1st, output inductor 2, high-frequency model 3, output detection module 4 and control module 5.It is input into the first output of main power model 1
Hold for being connected to the input of output inductor 2, being input into the second output end of main power model 1 is used to be connected to high-frequency model
3 inputs, the output end of output inductor 2 is used to be connected to the first input end of output detection module 4, and high-frequency model 3 is exported
The second input for being connected to output detection module 4 is held, exporting the first output end of detection module 4 is used to be connected to cutting torch
7, exporting the second output end of detection module 4 is used to be connected to workpiece 8, and output detection module 4 the 3rd output end is used to be connected to
Control module first input end, the output end of output detection module the 4th is used to be connected to the input of control module second, institute
Control module output end is stated for being connected to the main power model control end of output.
A kind of output overcurrent the invention provides plasma cutting power supply protects control method, comprises the steps：
(1) output current information (including the output current of current control period for being obtained according to data collecting module collected
The output current value of value and a upper controlling cycle), the output current value for calculating current control period is defeated with a upper controlling cycle
Go out the difference of current value as the current slope k of current control period, i.e. k=Ik-Ik-1；Wherein, IkIt is current control period
Output current value, Ik-1It is the output current value of a upper controlling cycle.
(2) judge whether the output current value of current control period protects limit value Ip more than output current, if so, then carrying out
Block is driven, terminates phase-shifting full-bridge module from service, current slope defence program；If it is not, being then transferred to step (3)；
(3) judge whether the current slope k of current control period protects limit value kp more than current slope, if so, then carrying out
Block is driven, makes phase-shifting full-bridge module from service；If it is not, being then transferred to step (4)；
(4) judge that current slope protection recovers whether clocking value N recovers timing threshold value a more than protection, if so, then recovering to drive
It is dynamic, according to the phase shift signal output drive signal that phase shift computing module is obtained, meanwhile, reset current slope protection and recover timing
Value, current slope defence program terminates；If it is not, being then driven block, make phase-shifting full-bridge module from service, meanwhile, electric current
Slope protection recovers clocking value N from adding, and current slope defence program terminates.
The present invention proposes a kind of output overcurrent protection control method of plasma cutting power supply, solves existing plasma and cuts
Cutting in power supply output current overcurrent protection scheme cannot be while takes into account the problem of high safety reliability and high efficiency, can
Protection probability by mistake is reduced while the safe and reliable work of guarantee plasma cutting power supply, while machine need not be restarted in protection by mistake
Device can work on, and production efficiency is greatly improved.
Fig. 1 shows the structural representation of plasma cutting power supply in the embodiment of the present invention, for convenience of description, only shows
The part related to the embodiment of the present invention, details are as follows：
The present invention relates to a kind of output overcurrent protection control circuit of plasma cutting power supply, including main power input module
1st, output inductor 2, high-frequency model 3, output detection module 4, control module 5.The output end of main power input module 1 first with
The input of output inductor 2 is connected, and the output end of main power input module 1 second is connected with the input of high-frequency model 3, output filter
The output end of ripple inductance 2 with output the first input end of detection module 4 be connected, the output end of high-frequency model 3 with export detection module 4 second
Input is connected, and the output output end of detection module 4 first is connected with tungsten electrode 6, exports the output end of detection module 4 second and workpiece 8
Connection, the output output end of detection module 4 the 3rd is connected with the first input end of control module 5, exports the output end of detection module 4 the 4th
It is connected with the input of control module 5 second, the output end of control module 5 is connected with the main control end of power input module 1.It is of the invention
Operation principle is divided into power flow and signal stream two parts, and from the angle of power flow, electric energy is input into by main power input module 1, stream
Filtered through output inductor 2, high-frequency model 3, output voltage, output current are detected by exporting detection module 4, most
Output to tungsten electrode 6, cutting torch 7, workpiece 8 carries out plasma cut work eventually；From the angle of signal stream, output voltage, output current
Signal, by obtaining drive signal after the internal calculation of control module 5, drives letter by the traffic organising module 5 of output detection module 4
Number stream flows to main power input module 1 by control module 5.Wherein, when there is no output overcurrent protection, drive signal stream is for just
Normal drive signal, driving transducer work, transmission energy；When there is output overcurrent protection, drive signal block drives letter
Number stream does not send signal, and converter is stopped.
Wherein, main power input module 1 includes the input ac power 10, the high-frequency rectification module 11, phase shift that are sequentially connected
Full-bridge modules 12；First output end of phase-shifting full-bridge module 12 is connected to the input of output inductor 2, phase-shifting full-bridge module
12 the second output end is connected to the input of high-frequency model 3.Main power input module 1 mainly transmits power flow, AC energy
Input ac power 10 is flowed into, and high-voltage direct-current electric energy is transformed to by high-frequency rectification module 11, then by phase-shifting full-bridge module
12 are transformed to the output of low-voltage direct-current electric energy.
Wherein, output detection module 4 predominantly detects the output current signal and output voltage signal of plasma cutting power supply,
For the control of plasma cutting power supply provides circuit parameter.Output detection module 4 includes current detection module 40, voltage detecting mould
Block 41；The input of the current detection module 40 is connected with the output end of output inductor 2, the current detection module 40
The first output end be connected with the first input end of voltage detection module 41, meanwhile, the first of the current detection module 40 is defeated
Go out end to be connected with tungsten electrode 6 as the first output end of the output detection module 4, the 3rd output of the current detection module 40
End is connected with the first input end of the phase shift computing module 51 of control module 5, the 4th output end of the current detection module 40
Input with the data acquisition module 52 of control module 5 is connected, second input and high frequency of the voltage detection module 41
The output end of module 3 is connected, and the first output end of the voltage detection module 41 is connected with workpiece 8, the voltage detection module
41 the second output end is used as the second of the phase shift computing module 51 of the 4th output end and the control module 5 of the detection module 4
Input is connected.Output detection module 4 transmits power flow and signal stream simultaneously, and output detection module 4 is flowed through in direct current energy
Meanwhile, output detection module 4 obtains output voltage, output current signal from direct current energy.Wherein, current detection module 40 is obtained
The current signal of direct current energy is taken, voltage detection module 41 obtains the voltage signal of direct current energy, while the letter for obtaining will be detected
Number it is transferred to control module 5.
Wherein, control module 5 is mainly used in calculating phase shifting angle according to output voltage, output current signal, and by output
Current signal determines whether block driving, final output or block drive signal.Control module 5 includes drive module 50, phase shift
Computing module 51, data acquisition module 52, logic synthesis module 53, protection recovery timer 54, current slope protection module 55,
Comparison module 56, current slope computing module 57, the second comparison module 58；The input and electric current of the data acquisition module 52
The secondary signal output end of detection module 40 is connected, and the first output end and the current slope of the data acquisition module 52 calculate mould
The input of block 57 is connected, the first input end phase of the second output end of the data acquisition module 52 and the second comparison module 58
Even, the output end of the current slope computing module 57 is connected with the first input end of comparison module 56, the comparison module 56
Output end be connected with the input of current slope comparison module 55, the first output end of the current slope protection module 55 with
The input that protection recovers timer 54 is connected, the second output end and the logic synthesis module of the current slope protection module 55
53 first input end is connected, the output end of the protection recovery timer 54 and the second input phase of logic synthesis module 53
Even, the output end of second comparison module 58 is connected with the 3rd input of logic synthesis module 53, the logic synthesis mould
The output end of block 53 is connected with the first input end of drive module 50, the first input end and electric current of the phase shift computing module 51
First signal output part of detection module 40 is connected, the second input and the voltage detection module of the phase shift computing module 51
Signal output part is connected, and the output end of the phase shift computing module 51 is connected with the second input of drive module 50.
Control module 5 is mainly used in transmitting signal stream, and its input is output voltage signal, output current signal, its output
It is drive signal.Wherein, data acquisition module 52 is gathered for circuit parameter, specifically includes the output current of current control period
Value Ik, a upper controlling cycle output current value Ik-1；Current slope computing module 57 is used for the output according to current control period
Current value Ik, a upper controlling cycle output current value Ik-1Calculate the current slope k of current control period；Comparison module 56
According to the current slope k of current control period logic comparative result is obtained with the current slope protection limit value kp computings of setting；Electric current
Whether protection module 55 sends the signal protected according to the logic comparative result of comparison module 56；The protection basis of recovery timer 54
The current protection signal of overcurrent protection module 55 determines whether that starting protection recovers timing, when protection recovery timer receives electricity
Timing is reset during stream protection signal, starts timing when protecting recovery timer not receive current protection signal, when electric current is oblique
When rate protection recovery clocking value N reaches protection recovery timing threshold value a, send protection and recover signal；Logic synthesis module 53 is used for
Recovering signal to current slope protection signal and protection carries out logic synthesis judgement, when current slope protection signal is invalid and protection
When recovery signal is effective, driving locking signal is not sent, otherwise send driving locking signal；Drive module 50 is used for the hair for driving
Go out or block, when drive module 50 receives the driving locking signal that logic synthesis module 53 sends, drive module block is driven
It is dynamic, drive signal is not sent, corresponding drive signal is otherwise generated simultaneously according to the phase shifting angle that phase shift computing module 51 is calculated
Drive signal is sent to the control end of phase-shifting full-bridge module 12, drive the work of phase-shifting full-bridge module.
The invention provides a kind of protection control method based on above-mentioned current slope protection circuit, the method is based on electric current
Slope realizes protection control：Output current value is first obtained, the current slope of current control period is calculated, then protect with current slope
Shield limit value relatively determines whether to send current slope protection signal, and current slope protection signal is recovered into signal and electric current with protection
Instantaneous value protection signal determines whether to send driving locking signal after carrying out logic synthesis, finally sends or block driving.
The flow chart of the control method is as shown in Fig. 2 specifically include：
(1) output current information (including the output current of current control period for being obtained according to data collecting module collected
The output current value of value and a upper controlling cycle), calculate the current slope k of current control period；
(2) judge whether the output current value of current control period protects limit value Ip more than output current, if so, then carrying out
Block is driven, terminates phase-shifting full-bridge module from service, current slope defence program；If it is not, being then transferred to step (3)；
(3) judge whether the current slope k of current control period protects limit value kp more than current slope, if so, then carrying out
Driving block, makes phase-shifting full-bridge module from service, meanwhile, current slope protection recovers clocking value N by 0 from adding, and often passes through
Cross a controlling cycle current slope protection recovery clocking value N and add 1, current slope defence program terminates；If it is not, being then transferred to step
(4)；
(4) judge that current slope protection recovers whether clocking value recovers timing threshold value more than protection, if so, then recovering to drive
It is dynamic, according to the phase shift signal output drive signal that phase shift computing module is obtained, meanwhile, current slope protection recovers clocking value N by 0
Start from adding, often recovering clocking value N by a controlling cycle current slope protection adds 1, and current slope defence program terminates；If
It is no, then block is driven, terminate phase-shifting full-bridge module from service, current slope defence program.
Fig. 3 show the oscillogram of slope protection during using guard method of the present invention, wherein, Dbs is driving locking signal,
Ik is the output current value at kth moment, and Uk is the output voltage values at phase-shifting full-bridge module kth moment.T1-T4 moment electric currents are with k1
Slope rises, and now current slope protects limit value less than current slope, and driving locking signal is not sent, and plasma cutting power supply is just
Often work；The T4-T5 moment current slope that breaks down is increased to k2, and now current slope protects limit value, hair more than current slope
Go out and drive locking signal, plasma cutting power supply is stopped, after waiting several controlling cycles, protect the counting of recovery timer
Reach protection and recover timing threshold value a, protection recovers, and driving locking signal is not sent, and plasma cutting power supply is resumed work.
Fig. 4 show the oscillogram of instantaneous value protection during using guard method of the present invention.T1-T5 moment electric power is oblique with k3
Rate rises, and now current slope is less than current slope protection value, plasma cutting power supply normal work；T5 moment current instantaneous values
Instantaneous value protection point is risen to, driving locking signal is sent, plasma cutting power supply is stopped, wait several controlling cycles
Afterwards, protection recovery timer counting reach protection recover timing threshold value a, protection recover, driving locking signal is not sent, wait from
Sub- cutting power supply is resumed work.
Control method of the invention needs to design three parameters, specifically includes：
(1) current slope protection limit value
Current slope protection limit value should allow maximum current climbing to determine according to system, typically it is determined that allowing maximum electricity
Certain allowance is taken after stream climbing, is taken as allowing the 0.85-0.95 of maximum current climbing.Current slope protects limit value with output
Current slope change when inductance inductance value, switching frequency, control frequency and normal work is relevant.Outputting inductance inductance value is bigger, hair
Current slope during raw failure is smaller；Under same switch frequency, control frequency is higher, the current slope protection limit value of required setting
Can be bigger；Under identical control frequency, switching frequency is higher, and the current slope protection limit value of required setting is smaller；And set
Current slope protection limit value have to be larger than current slope value during normal work, and protection probability by mistake is reduced as far as possible.Electric current is oblique herein
Rate protection limit value is taken as 60A/Tc.
(2) current instantaneous value protection limit value
Current instantaneous value protection limit value should determine according to the maximum allowable operating current point of system, typically it is determined that maximum allowable
Certain allowance is taken after operating current, the 0.85-0.95 of maximum allowable operating current is taken as.The present invention is using current instantaneous value protection
With the protection control method that current slope protection is combined, on the premise of current slope protection safeguards system safety, Ke Yishi
Limit value is protected when current instantaneous value is relaxed.The limit value of current instantaneous value protection herein is taken as 130A.
(3) protection recovers timing threshold value
When there is the overcurrent protection due to the triggering of the reasons such as misoperation, workpiece surface out-of-flatness, should be in protection
Recovery timer recovers to drive after reaching timing threshold value, plasma cutting power supply is worked on.Protection recovers timing threshold value should
Determined according to electric current recovery time after protection, generally 10-100 controlling cycle, i.e., described protection recovers timing threshold value a and is
10-100.The selection that protection recovers timing threshold value is relevant with outputting inductance, and outputting inductance is bigger, and electric current drops to after protecting
More long the time required to zero, the timing threshold value of required setting is more long.Protection herein recovers timing threshold value a and is taken as 50.
Fig. 5 is shown using current protection method of the present invention, when current slope exceedes current slope protection limit value
The oscillogram of Shi Fasheng protections, current slope exceedes current slope protection limit value and current instantaneous value is not up to current instantaneous value guarantor
During shield limit value trigger protection is remained to, by the imminent overcurrent failure of current slope anticipation, the effective guarantee peace of system
Full reliably working；Fig. 6 is shown using current protection method of the present invention, when current instantaneous value is protected more than current instantaneous value
The oscillogram protected during shield limit value, current instantaneous value exceedes current instantaneous value protection limit value and current slope is not up to electric current
Can correctly set out protection during slope protection limit value, and this is consistent with conventional current guard method operation principle, but it is oblique to combine electric current
Rate protection can suitably relax current instantaneous value protection limit value, reduce the possibility that system occurs protection by mistake, improve system life
Produce efficiency.
As it will be easily appreciated by one skilled in the art that the foregoing is only presently preferred embodiments of the present invention, it is not used to
The limitation present invention, all any modification, equivalent and improvement made within the spirit and principles in the present invention etc., all should include
Within protection scope of the present invention.
Claims (7)
1. the output overcurrent protection of a kind of plasma cutting power supply controls circuit, it is characterised in that including：It is input into main power model
(1), output inductor (2), high-frequency model (3), output detection module (4) and control module (5)；
The input of the output inductor (2) is connected to the first output end of the main power model (1) of input, the height
The input of frequency module (3) is connected to the second output end of the main power model (1) of input, the output detection module (4)
First input end be connected to the output end of the output inductor (2), the second input of the output detection module (4)
The output end of the high-frequency model (3) is connected to, the first output end of the output detection module (4) is used to be connected to tungsten electrode
(6), the second output end of output detection module (4) is used to be connected to for being connected to workpiece (8), the output detection mould
3rd output end of block (4) is connected to the first input end of the control module (5), the 4th of the output detection module (4) the
Output end is connected to the second input of the control module (5), and the output end of the control module (5) is connected to the input
The control end of main power model (1).
2. output overcurrent protection as claimed in claim 1 controls circuit, it is characterised in that during work, the main power input
The electric energy of input is converted to low-voltage direct-current electric energy by module, and is filtered through the output inductor and the high-frequency model
Afterwards, detect that final output to tungsten electrode, cutting torch and workpiece enter to output voltage and output current by the output detection module
Row plasma cut works；Output voltage signal and output current that the control module is detected according to the output detection module
Signal output is used to control the drive signal of the main power input module；When there is output overcurrent, the drive signal control
The main power input module from service is made, so as to realize overcurrent protection.
3. output overcurrent protection as claimed in claim 1 or 2 controls circuit, it is characterised in that the output detection module (4)
Including：Current detection module (40) and voltage detection module (41)；
The input of the current detection module (40) is used as the first input end for exporting detection module (4), the electric current
First output end of detection module (40) is used as first output end for exporting detection module (4), the current detection module
(40) the second output end is used as the 3rd output end for exporting detection module (4)；
First output end phase of the first input end of the voltage detection module (41) and the output electric current measure module (40)
Even, the second input of the voltage detection module (41) as output detection module (4) the second input, while
Used as the second output end of output detection module (4), the first output end of the voltage detection module (41) is used as described
4th output end of output detection module (4).
4. the output overcurrent protection as described in claim any one of 1-3 controls circuit, it is characterised in that the control module
(5) include：Drive module (50), phase shift computing module (51), data acquisition module (52), logic synthesis module (53), protection
Recovery timer (54), current slope protection module (55), comparison module (56), current slope computing module (57) and the second ratio
Compared with module (58)；
The first input end of the drive module (50) is connected with the first output end of the integrated logic module (53), the drive
Second input of dynamic model block (50) is connected with the first output end of the phase shift computing module (51), the drive module (50)
The first output end as the control module (5) the first output end；
The first input end of the phase shift computing module (51) and the first input end phase continuous cropping of the data acquisition module (52)
It is the first input end of the control module (5), the second input of the phase shift computing module (51) is used as the control mould
Second input of block (5), the first output end of the phase shift computing module (51) is defeated with the second of the drive module (50)
Enter end to be connected；
The first input end phase continuous cropping of the first input end of the data acquisition module (52) and the phase shift computing module (51)
It is the first input end of the control module (5), first output end and the current slope of the data acquisition module (52)
The first input end of computing module (57) is connected, and the second output end of the data acquisition module (52) compares mould with described second
The first input end of block (58) is connected；
First output end of current slope protection module (55) described in the first input end of the logic synthesis module (53) is connected,
Second input of the logic synthesis module (53) is connected with the first output end of protection recovery timer (54), described
3rd input of logic synthesis module (53) is connected with the first output end of second comparison module (58)；
The first input end of protection recovery timer (54) and the first output end of the current slope protection module (55)
Be connected, it is described protection recovery timer (54) the first output end and the logic synthesis module (53) the second input phase
Even；
The first input end of the current slope protection module (55) is connected with the first output end of the comparison module (56), institute
The first output end for stating current slope protection module (55) is connected with the first input end of the logic synthesis module (53), while
First output end of the current slope protection module (55) is connected with the first input end of protection recovery timer (54)；
The first input end of the comparison module (56) is connected with the first output end of the current slope computing module (57), institute
The second input of comparison module (56) is stated for slope protects limit value km, the first output end of the comparison module (56) with it is described
The first input end of current slope protection module (55) is connected；
The first input end of the current slope computing module (57) and the first output end phase of the data acquisition module (52)
Even, the first output end of the current slope computing module (57) is connected with the first input end of the comparison module (56)；
The first input end of second comparison module (58) is connected with the second output end of the data acquisition module (52), institute
It is current instantaneous value protection limit value Ip to state the second input of the second comparison module (58)；
The data acquisition module (52) is for gathering the output current value I of current control periodk, a upper controlling cycle output
Current value Ik-1；
The current slope computing module (57) is for the output current value I according to current control periodk, a upper controlling cycle
Output current value Ik-1Calculate the current slope k of current control period；
The comparison module (56) protects limit value kp for the current slope k according to current control period with the current slope of setting
Computing obtains logic comparative result；
Whether the overcurrent protection module (55) sends the signal protected according to the logic comparative result；
Protection recovery timer (54) determines whether to start protection according to the current protection signal of overcurrent protection module (55)
Recover timing, timing is reset when protecting recovery timer to receive current protection signal, when protection recovery timer is not received
Start timing during to current protection signal, when current slope protection recovers clocking value N reaches protection recovery timing threshold value a, hair
Go out protection and recover signal；
The logic synthesis module (53) carries out logic synthesis judgement for recovering signal to current slope protection signal and protection,
When current slope protection signal is invalid and protection recovery signal is effective, driving locking signal is not sent, otherwise send driving envelope
Lock signal；
The drive module (50) sending or blocking for what is driven, when drive module (50) receives logic synthesis module (53)
During the driving locking signal for sending, drive module block drives, and drive signal is not sent, otherwise according to phase shift computing module (51)
The phase shifting angle being calculated generates corresponding drive signal and sends drive signal to the control of the main power model (1) of input
End processed, drives main power model (1) work of the input.
5. output overcurrent protection as claimed in claim 4 controls circuit, it is characterised in that the current slope protection limit value of setting
Kp is the 0.85-0.95 that system allows maximum current climbing, and current instantaneous value protection limit value Ip is that system allows maximum functional
The 0.85-0.95 of electric current, it is 10-100 that protection recovers timing threshold value.
6. a kind of output overcurrent of plasma cutting power supply protects control method, it is characterised in that comprise the steps：
(1) the output current value I of current control period is gatheredkWith the output current value I of a upper controlling cyclek-1, and according to formula k
=Ik-Ik-1Calculate the current slope k of current control period；
(2) judge whether the output current value of current control period protects limit value Ip more than output current, if so, being then driven
Block, makes phase-shifting full-bridge module from service；If it is not, being then transferred to step (3)；
(3) judge whether the current slope k of current control period protects limit value kp more than current slope, if so, being then driven
Block, makes phase-shifting full-bridge module from service；If it is not, being then transferred to step (4)；
(4) judge that current slope protection recovers whether clocking value recovers timing threshold value more than protection, if so, then recovering to drive, root
The phase shift signal output drive signal obtained according to phase shift computing module, and N=0；If it is not, being then driven block, make phase shift complete
Bridge module is stopped, and N=N+1.
7. output overcurrent as claimed in claim 6 protects control method, it is characterised in that the current slope protection limit value of setting
Kp is the 0.85-0.95 that system allows maximum current climbing, and current instantaneous value protection limit value Ip is that system allows maximum functional
The 0.85-0.95 of electric current, it is 10-100 that protection recovers timing threshold value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710165104.1A CN106862737B (en) | 2017-03-20 | 2017-03-20 | A kind of the output overcurrent protection control circuit and method of plasma cutting power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710165104.1A CN106862737B (en) | 2017-03-20 | 2017-03-20 | A kind of the output overcurrent protection control circuit and method of plasma cutting power supply |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106862737A true CN106862737A (en) | 2017-06-20 |
| CN106862737B CN106862737B (en) | 2018-11-30 |
Family
ID=59173407
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710165104.1A Active CN106862737B (en) | 2017-03-20 | 2017-03-20 | A kind of the output overcurrent protection control circuit and method of plasma cutting power supply |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106862737B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110095733A (en) * | 2018-01-26 | 2019-08-06 | 崔云善 | The self diagnosis module and self-diagnosing method of plasma power supply unit |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5844197A (en) * | 1997-07-28 | 1998-12-01 | The Lincoln Electric Company | Arc retract circuit and method |
| CN1557597A (en) * | 2004-01-15 | 2004-12-29 | 沈阳工业大学 | Multifunctional integrated welding and cutting equipment |
| CN201797448U (en) * | 2010-09-25 | 2011-04-13 | 哈尔滨工业大学 | Full PLC-based high-voltage pulse power supply |
| CN203541830U (en) * | 2013-09-23 | 2014-04-16 | 无锡精工焊接设备有限公司 | Inverter air plasma cutting machine |
| CN105414728A (en) * | 2015-12-25 | 2016-03-23 | 华中科技大学 | Single-sensor arc striking circuit and control method thereof for air plasma cutter |
-
2017
- 2017-03-20 CN CN201710165104.1A patent/CN106862737B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5844197A (en) * | 1997-07-28 | 1998-12-01 | The Lincoln Electric Company | Arc retract circuit and method |
| CN1557597A (en) * | 2004-01-15 | 2004-12-29 | 沈阳工业大学 | Multifunctional integrated welding and cutting equipment |
| CN201797448U (en) * | 2010-09-25 | 2011-04-13 | 哈尔滨工业大学 | Full PLC-based high-voltage pulse power supply |
| CN203541830U (en) * | 2013-09-23 | 2014-04-16 | 无锡精工焊接设备有限公司 | Inverter air plasma cutting machine |
| CN105414728A (en) * | 2015-12-25 | 2016-03-23 | 华中科技大学 | Single-sensor arc striking circuit and control method thereof for air plasma cutter |
Non-Patent Citations (1)
| Title |
|---|
| 司冬子 等: ""逆变电源过流保护策略研究"", 《通信电源技术》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110095733A (en) * | 2018-01-26 | 2019-08-06 | 崔云善 | The self diagnosis module and self-diagnosing method of plasma power supply unit |
| CN110095733B (en) * | 2018-01-26 | 2021-09-24 | 帕沃菲克特斯公司 | Self-diagnosis module and self-diagnosis method of plasma power supply device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106862737B (en) | 2018-11-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106026157B (en) | Flexible direct current transmission converter valve sub-module fault prediction technique and device | |
| CN1044536C (en) | Power converter protecting apparatus for electric power system | |
| CN102842887B (en) | Anti-interference electricity protection method and anti-interference electricity protection device for electric equipment | |
| CN102223125B (en) | Method and device for controlling uninterruptible operation of wind generator system in case of faulted power grid voltage | |
| CN102222904B (en) | Direct-current dual-circuit power supply for supplying power | |
| CN103346528A (en) | Current limiting type hybrid direct-current circuit breaker based on power electronic combination switch | |
| CN102522725B (en) | Intelligent overcurrent protection circuit for integrated circuit test system | |
| CN102491137A (en) | Double digital signal processor(DSP)-based elevator drive, control and energy conservation integrated system and method | |
| CN100561628C (en) | Low voltage electrical appliance intelligent control method based on current-varying mode | |
| CN110416974A (en) | A kind of protective circuit of switch power source, Switching Power Supply and Switching Power Supply guard method | |
| CN201616653U (en) | Drive protection circuit used for EP valve and skid-proof valve | |
| CN104158152B (en) | A kind of motor driver protection circuit and means of defence | |
| CN103928918A (en) | Removing system and method for transformation type high-voltage direct-current breaker short-circuit fault | |
| CN102148529B (en) | Control device and control method thereof for intelligently supplying power to circuit breaker control unit | |
| CN102655385B (en) | Threephase asynchronous machine soft starter and control method thereof | |
| CN106862737B (en) | A kind of the output overcurrent protection control circuit and method of plasma cutting power supply | |
| CN104767368A (en) | High-reliable tri-level inverter circuit current-limiting control method | |
| CN205647018U (en) | Circuit breaker controller based on syllogic electric current method cooperation communication system | |
| CN202121543U (en) | AC motor driving device with vector control used in variable-pitch control system | |
| CN104167716A (en) | Protection control method and system of power factor correction circuit | |
| CN113514762A (en) | System for detecting state of APF/SVG relay | |
| CN106787653A (en) | A kind of drive control method and power circuit | |
| CN103474964B (en) | A kind of prevent inversion from overturning intelligent overcurrent protective device and control method | |
| CN103715656B (en) | The over-pressure safety device of chopper, chopper and electric locomotive | |
| CN204696029U (en) | Monostable permanent magnetic mechanism controller and there is its vacuum circuit-breaker |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |