CN110957903A - Arc power supply system and arc power supply based on trapezoidal wave signal - Google Patents
Arc power supply system and arc power supply based on trapezoidal wave signal Download PDFInfo
- Publication number
- CN110957903A CN110957903A CN201911162867.6A CN201911162867A CN110957903A CN 110957903 A CN110957903 A CN 110957903A CN 201911162867 A CN201911162867 A CN 201911162867A CN 110957903 A CN110957903 A CN 110957903A
- Authority
- CN
- China
- Prior art keywords
- arc
- voltage
- current
- inverter
- power supply
- 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.)
- Pending
Links
- 238000006243 chemical reaction Methods 0.000 claims abstract description 27
- 238000002485 combustion reaction Methods 0.000 claims abstract description 23
- 238000004804 winding Methods 0.000 claims abstract description 10
- 238000010304 firing Methods 0.000 claims description 4
- 238000010891 electric arc Methods 0.000 abstract description 5
- 238000010586 diagram Methods 0.000 description 22
- 238000001514 detection method Methods 0.000 description 11
- 238000000034 method Methods 0.000 description 9
- 230000001105 regulatory effect Effects 0.000 description 7
- 239000013307 optical fiber Substances 0.000 description 6
- 230000002238 attenuated effect Effects 0.000 description 5
- 230000001276 controlling effect Effects 0.000 description 5
- 230000001965 increasing effect Effects 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 239000013308 plastic optical fiber Substances 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 238000011946 reduction process Methods 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
- H02M1/4208—Arrangements for improving power factor of AC input
-
- 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
- B23K9/00—Arc welding or cutting
- B23K9/10—Other electric circuits therefor; Protective circuits; Remote controls
- B23K9/1006—Power supply
- B23K9/1043—Power supply characterised by the electric circuit
- B23K9/1056—Power supply characterised by the electric circuit by using digital means
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
- H02M5/40—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc
- H02M5/42—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters
- H02M5/44—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac
- H02M5/453—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal
- H02M5/458—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M5/4585—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only having a rectifier with controlled elements
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- Mechanical Engineering (AREA)
- Arc Welding Control (AREA)
Abstract
The invention discloses an arc power supply system and an arc power supply based on a trapezoidal wave signal, wherein the arc power supply system comprises: a control system and a power conversion circuit; wherein, power conversion circuit includes: a transformer, a rectifier and an inverter; the primary winding of the transformer is connected with an alternating current power grid; the secondary winding of the transformer is connected with the alternating current input end of the rectifier; the direct current output end of the rectifier is connected with the direct current input end of the inverter through a direct current bus; the alternating current output end of the inverter is connected with the arc equipment; and the control system is respectively connected with the power conversion circuit and the arc equipment and is used for acquiring the arc voltage or the arc current of the arc equipment and controlling an inverter in the power conversion circuit to output a trapezoidal wave voltage signal meeting the stable arc combustion condition according to the arc voltage or the arc current of the arc equipment. The invention can provide the trapezoidal wave alternating current signal required by the stable burning electric arc of the electric arc equipment under the condition that the power supply loop does not need to be connected with the inductor in series.
Description
Technical Field
The invention relates to the field of arc power supply, in particular to an arc power supply system and an arc power supply based on a trapezoidal wave signal.
Background
This section is intended to provide a background or context to the embodiments of the invention that are recited in the claims. The description herein is not admitted to be prior art by inclusion in this section.
Ac arc heating is widely used in arc devices such as ac arc furnaces, arc welders and the like, since the ac power supply varies periodically (50 times per second) from zero, a forward maximum, zero, a reverse maximum, a course of zero at its frequency (e.g. 50 Hz). Fig. 1 is a waveform diagram of a time-varying arc voltage and current provided in the prior art, as shown in fig. 1, since an ac arc itself has non-linear impedance characteristics, a certain initial voltage (i.e., an arc-burning voltage Ui) is required for igniting the arc, and a burning arc voltage Ua decreases as the current Ia increases (negative impedance characteristics) until the arc is extinguished when the arc voltage decays to a certain voltage (arc-extinguishing voltage Ue).
Currently, it is widely accepted in the industry that alternating current arcs have non-linear resistance characteristics. In a purely resistive or insufficiently inductive circuit, however, the arc is not continuously burning as the current and voltage phases are close, and the arc is frequently ignited and extinguished periodically at twice the ac power frequency (e.g., 50Hz) during the burning of the arc. In order to achieve the purpose of stable combustion of the alternating current arc, in the conventional arc power supply circuit, an inductor (the inductance value is generally not lower than 30% of a per unit value based on the loop capacity) is connected in series in a power supply loop of the arc, and at the moment when the arc is extinguished, because the current change rate is large, a higher induced voltage is generated at two ends of the inductor, and the induced voltage is superposed with a power supply voltage and then is greater than the arcing voltage of the arc, so that the arc current is continuously uninterrupted, and the purpose of stable combustion of the arc is achieved, as shown in fig. 2, waveforms of the arc voltage and the current, which change along with time, after the inductor is connected in series in the power supply loop.
Fig. 3 shows an arc power supply circuit with an inductor connected in series, and as shown in fig. 3, the inductor connected in series in the arc power supply loop can lead to the current phase of the power supply loop lagging behind the system voltage, which results in the overall power factor of the power supply loop being low, the active loss being large and the power utilization efficiency being low.
In view of the above problems, no effective solution has been proposed.
Disclosure of Invention
The embodiment of the invention provides an arc power supply system based on a trapezoidal wave signal, which is used for solving the technical problems that the existing arc power supply system is connected with an inductor in series in a power supply loop to provide alternating current for stable combustion of an arc, and the inductor causes the current in the power supply loop to have hysteresis so as to cause the total power factor of the power supply loop to be lower, the active loss to be increased and the power utilization efficiency to be lower, and comprises the following components: a control system and a power conversion circuit; wherein, power conversion circuit includes: a transformer, a rectifier and an inverter; the primary winding of the transformer is connected with an alternating current power grid; the secondary winding of the transformer is connected with the alternating current input end of the rectifier; the direct current output end of the rectifier is connected with the direct current input end of the inverter through a direct current bus; the alternating current output end of the inverter is connected with the arc equipment; and the control system is respectively connected with the power conversion circuit and the arc equipment and is used for acquiring the arc voltage or the arc current of the arc equipment and controlling an inverter in the power conversion circuit to output a trapezoidal wave voltage signal meeting the stable arc combustion condition according to the arc voltage or the arc current of the arc equipment.
The embodiment of the present invention further provides an arc power supply, which is used to solve the technical problems that an inductance is connected in series in a power supply loop of the existing arc power supply system to provide alternating current for stable combustion of an arc, and the inductance causes hysteresis in the current in the power supply loop, so that the overall power factor of the power supply loop becomes low, the active loss increases, and the power consumption efficiency becomes low, and the arc power supply comprises: the arc power supply system based on the trapezoidal wave signal is described above.
In the embodiment of the invention, the alternating current of an alternating current network is converted into the alternating current required by the arc equipment through the power converter consisting of the transformer, the rectifier and the inverter, the control system acquires the arc voltage or the arc current of the arc equipment, and the inverter in the power conversion circuit is controlled to output the trapezoidal wave voltage signal meeting the stable arc combustion condition according to the arc voltage or the arc current of the arc equipment.
The arc power supply system and the arc power supply provided by the embodiment of the invention can provide a trapezoidal wave alternating current signal required by stable combustion arc of arc equipment under the condition of not connecting an inductor in series.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts. In the drawings:
FIG. 1 is a waveform diagram of arc voltage and current over time as provided in the prior art;
fig. 2 is a waveform diagram of the arc voltage and current with time variation after an inductor is connected in series in a power supply loop of an arc device in the prior art;
FIG. 3 is a schematic diagram of an arc supply circuit provided in the prior art;
fig. 4 is a schematic diagram of an arc power supply system based on a trapezoidal wave signal according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a trapezoidal wave voltage signal according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of an alternative arc power supply system according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of an alternative voltage signal conversion circuit according to an embodiment of the present invention;
FIG. 8 is a schematic diagram of an alternative current signal conversion circuit according to an embodiment of the present invention;
fig. 9 is a schematic diagram of an alternative dc bus voltage signal acquisition circuit according to an embodiment of the present invention;
fig. 10 is a schematic diagram illustrating a connection between a shift control signal output circuit and a transformer according to an embodiment of the present invention;
fig. 11 is a schematic diagram illustrating a connection between a rectifier and a rectification control signal output circuit according to an embodiment of the present invention;
fig. 12 is a schematic connection diagram of an inverter control signal output circuit and an inverter according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings. The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention.
In the description of the present specification, the terms "comprising," "including," "having," "containing," and the like are used in an open-ended fashion, i.e., to mean including, but not limited to. Reference to the description of the terms "one embodiment," "a particular embodiment," "some embodiments," "for example," etc., means that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. The sequence of steps involved in the embodiments is for illustrative purposes to illustrate the implementation of the present application, and the sequence of steps is not limited and can be adjusted as needed.
An embodiment of the present invention provides an arc power supply system based on a trapezoidal wave signal, and fig. 4 is a schematic diagram of an arc power supply system based on a trapezoidal wave signal according to an embodiment of the present invention, as shown in fig. 4, the arc power supply system includes: a control system 10 and a power conversion circuit 20;
wherein, power conversion circuit includes: a transformer 201, a rectifier 202, and an inverter 203; the primary winding of the transformer is connected with an alternating current power grid; the secondary winding of the transformer 201 is connected to the ac input of the rectifier 202; the direct current output end of the rectifier 202 is connected with the direct current input end of the inverter 203 through a direct current bus; the ac output of the inverter 203 is connected to the arc device 30;
the control system 10 is connected to the power conversion circuit 20 and the arc device 30, and configured to collect an arc voltage or an arc current of the arc device 30, and control the inverter 203 in the power conversion circuit 20 to output a trapezoidal wave voltage signal meeting an arc stable combustion condition according to the arc voltage or the arc current of the arc device 30.
It should be noted that, in the arc power supply system provided by the embodiment of the present invention, the control system 10 may be used to implement, but is not limited to, ① data acquisition, which includes acquiring a primary/secondary voltage of a transformer and a position of a voltage regulating switch, acquiring a dc bus voltage, and current and voltage values at an inverter output side, ② control functions, which include controlling the position of the voltage regulating switch of the transformer to obtain a desired dc bus voltage and a power factor at a power supply side, controlling a trigger angle of a rectifier to obtain a desired dc bus voltage, and controlling waveform, amplitude, and frequency adjustment of the output voltage of the inverter to complete arc stabilization and arc power control.
As shown in fig. 4, the power conversion circuit 20 is composed of a transformer 201, a rectifier 202, and an inverter 203. The transformer can convert the standard alternating current voltage value of the system into a voltage value required by the rectifier according to a transformation ratio, and the voltage value can be a fixed value or an adjustable value within a certain range; the rectifier can convert the secondary voltage of the transformer into direct-current voltage in a controllable or uncontrollable rectification mode; the inverter can convert the direct-current voltage into voltage waveform, amplitude and frequency required by normal and stable combustion of the arc, and the output current value is controlled to meet the requirement of arc power.
The amplitude of the output voltage of the inverter can meet the voltage value required by arc stable combustion, the modulation method of the output voltage of the inverter comprises any one of ① or any combination of two or three of the following steps that the voltage value of a direct current side is adjusted through a transformer or a rectifier, the voltage amplitude is not adjusted on an inversion side, the voltage direction is only switched once in a half period, the voltage of a ② direct current bus is kept unchanged, the on-state voltage time occupying ratio of the output side is adjusted through multiple on-off of the inversion side in the half period, and the voltage amplitude is modulated according to the arc length requirement of the arc by adopting a multi-level inverter ③.
In one embodiment, the frequency of the amplitude of the inverter output voltage may be varied between a lower (e.g., below 10Hz) and a higher (e.g., above 100Hz) frequency range, and the adjustment may be by changing the direction of the voltage at the output side of the inverter.
It should be noted that the dc voltage output by the rectifier can be adjusted within a certain range, and the adjusting method includes, but is not limited to, ① adjusting the secondary voltage of the transformer by changing the transformation ratio of the transformer, ② changing the firing angle of the rectifier to adjust the conduction time of the rectifier.
In order to allow the inverter to output a trapezoidal wave voltage signal satisfying the arc stable combustion condition, the dc voltage at the dc input terminal of the inverter may be controlled, and the voltage at the ac output terminal of the inverter may also be controlled. Therefore, in order to provide a trapezoidal wave voltage signal satisfying the arc-stabilized combustion condition, the embodiments of the present invention may be implemented by, but not limited to, any one of the following manners, or a combination of the following manners:
in the first embodiment, the position of a voltage regulating switch on the transformer is controlled by a control system, so that the inverter outputs a trapezoidal wave voltage signal meeting the stable arc combustion condition. Optionally, in this embodiment, the control system is further configured to collect a primary voltage and a secondary voltage of the transformer, and determine a position of the voltage regulating switch on the transformer according to the primary voltage and the secondary voltage of the transformer.
In the second embodiment, the trigger angle conduction time of the rectifier is controlled by the control system, so that the inverter outputs a trapezoidal wave voltage signal meeting the arc stable combustion condition. Optionally, in this embodiment, the control system is further configured to collect an ac voltage at the ac input terminal of the rectifier and a dc voltage at the dc output terminal of the rectifier, and determine the conduction time of the firing angle of the rectifier according to the ac voltage at the ac input terminal of the rectifier and the dc voltage at the dc output terminal of the rectifier.
In the third embodiment, the voltage duty ratio of the inverter output voltage signal is controlled by the control system, so that the inverter outputs a trapezoidal wave voltage signal satisfying the arc stable combustion condition. Optionally, in this embodiment, the control system is further configured to collect a dc voltage at the dc input terminal of the inverter and an ac voltage at the ac output terminal of the inverter, and determine a voltage duty ratio of the inverter output voltage signal according to the dc voltage at the dc input terminal of the inverter and the ac voltage at the ac output terminal of the inverter.
It is noted that in order to achieve frequency adjustment of the inverter output voltage signal, the direction of the inverter output voltage signal may be changed by the control system.
Fig. 5 is a schematic diagram of a trapezoidal wave voltage signal according to an embodiment of the present invention, as shown in fig. 5, when the control system 10 controls the inverter in the power conversion circuit 20 to output a trapezoidal wave voltage signal meeting the arc stable combustion condition, the control system 10 may control the inverter in the power conversion circuit 20 to output the following voltage signal U in each voltage modulation period:
wherein, t1The time when the arc current decays to zero in the last voltage modulation period; t is t2The moment when the arc current rises from zero to the forward maximum current value; t is t3The moment when the arc current starts to decay from the forward maximum current value; t is t4The moment when the arc voltage decays from the forward maximum voltage value to zero; t is t5The time when the arc current decays from the forward maximum voltage value to zero; t is t6The moment when the arc current decays from zero to a negative maximum current value; t is t7The time when the arc current starts to rise from the negative maximum current value is taken as the time; t is t8The moment when the arc voltage rises to zero from a negative maximum voltage value; t is t9At the moment when the arc current rises from the negative maximum current value to zero,
f is the frequency of the trapezoidal wave voltage signal.
The following is a detailed description of the various stages.
① at 0-t1In the stage, the voltage output is 0, and the arc current gradually decays to 0 in the last voltage modulation period; t is t1The parameters related to the reactor, the arc equivalent resistance, the arc equivalent reactance and the like are one of the key parameters for stabilizing the arc.
② at t1～t2The voltage output is a linear increasing process, and the process is a process that the reactor gradually forms stable maximum current, so as to prevent the voltage from changing too fast. If the voltage is increased too quickly, the reactor may be caused to enter an electromagnetic saturation region, generating a non-linear current, such that the arc voltage may not meet expectations.
③ at t2～t3And in the stage, the voltage output is a stable value M, the forward arc is quickly established in the stage, the arc current maintains the forward maximum value, the more stable the voltage output is, the more continuous the change of the arc current is, meanwhile, the process of quickly converting electric energy into arc heat is also adopted, and the method is an optimization method for stabilizing the arc and improving the arc transmission power.
④ at t3～t4In the stage, the voltage is gradually reduced, the current in the reactor is gradually attenuated to 0, the reduction process needs to be set in cooperation with the parameters of the reactor, and the optimal control result is that the voltage is gradually reduced, the current in the reactor is gradually attenuated to 0, and the optimal control result is at t4At the moment the voltage and current reach 0 simultaneously.
⑤ at t4～t5And in stage, the voltage output is 0. Wait for t1～t4The arc current of the stage gradually decays to 0; like 0 to t1And (5) stage. Uncertainties in the equivalent resistance, equivalent reactance of the system, including the coupling between the three phases of the system, may result in t4The current is not zero at time t4～t5And stage, controlling the voltage output to be 0.
⑥ at t5～t6In stages, the voltage is gradually decreased from 0 to a steady value-M, like t1～t2And (5) stage.
⑦ at t6～t7The voltage output is a stable value-M, the negative arc is rapidly established in the phase, the arc current maintains a negative maximum value, and the like t2～t3And (5) stage.
⑧ at t7～t8Step-wise increment of the voltage output from a steady value-M to 0, like t3～t4And (5) stage.
⑨ at t8～t9Stage, voltage output is 0, wait for t5～t8The arc current of the stage gradually decays to 0; like 0 to t1And (5) stage.
Fig. 6 is a schematic diagram of an alternative arc power supply system according to an embodiment of the present invention, and as shown in fig. 6, in the arc power supply system, a control system 10 includes: the system comprises a controller 100, an arc voltage/current signal acquisition circuit 101, an inversion control signal output circuit 102 and a direct current bus voltage signal acquisition circuit 103; an arc voltage/current signal acquisition circuit 101 connected between the controller 100 and the arc device 30 for transmitting an arc voltage/current signal of the arc device 30 to the controller 100; the direct current bus voltage signal acquisition circuit 103 is connected between the controller 100 and the direct current bus and used for transmitting a direct current voltage signal of the direct current bus to the controller 100; and an inversion control signal output circuit 102 connected between the controller 100 and the inverter 203, for transmitting the inversion control signal output by the controller 100 to the inverter 203.
Since the electrical signals (voltage/current signals) in the power conversion circuit are high-voltage electrical signals; the electrical signals (voltage/current signals) required by the controller in the control system are low-voltage electrical signals; therefore, as an optional implementation manner, in the power supply circuit provided in the embodiment of the present invention, the arc voltage/current signal collecting circuit 101 includes: and a first voltage/current transformer connected between the controller 100 and the arc device 30 for converting the high voltage electrical signal output by the arc device 30 into a low voltage electrical signal required by the controller 100. The voltage transformer in the arc voltage/current signal acquisition circuit 101 can convert a high-voltage signal into a low-voltage signal.
Fig. 7 is a schematic diagram of an alternative voltage signal conversion circuit according to an embodiment of the present invention, and as shown in fig. 7, there are 3 power supply cables, each of which is A, B, C phases, in total. The voltage transformer is used as a detection component, the high-voltage signal can be attenuated into a low-voltage signal (for example, a voltage signal of 100V), and the low-voltage signal is collected and input to the controller through the voltage signal collecting circuit. The signal input side of the voltage transformer has 6 signal lines, and the signal output side has 3 signal lines. 3 high-voltage signals are transmitted to a voltage signal acquisition circuit through 3 signal wires on the signal output side of the voltage transformer, and 3 low-voltage signals are obtained. That is, the first voltage transformer converts the high voltage signals Ua, Ub, Uc of the arc device into low voltage signals PT3-A, PT3-B, PT 3-C.
Fig. 8 is a schematic diagram of an alternative current signal conversion circuit according to an embodiment of the present invention, and as shown in fig. 8, there are 3 power supply cables, each having A, B, C phases, in total for the high-voltage cable. The current transformer is used as a detection component, a high-voltage current signal can be attenuated into a low-voltage current signal (for example, a 1A current signal), and the low-voltage current signal is acquired and input to the controller through the current signal acquisition circuit. The signal input side of the current transformer has 6 signal lines, and the signal output side has 6 signal lines. 3 high-voltage current signals are transmitted to the current signal acquisition circuit through 6 signal wires on the signal output side of the current transformer, and 6 low-voltage current signals are obtained. Namely, the first current transformer converts the high-voltage current signals Ia, Ib and Ic of the arc equipment into low-voltage current signals CT-A1, CT-A2, CT-B1, CT-B2, CT-C1 and CT-C2.
Fig. 9 is a schematic diagram of an optional dc bus voltage signal acquisition circuit according to an embodiment of the present invention, and as shown in fig. 9, the dc bus voltage detection is to detect the output voltage of the rectifier, and the output voltage is charged by the dc capacitor and becomes a dc current. The high-voltage direct current voltage is attenuated into low-voltage direct current (for example, 0 to +10V voltage) through a direct current bus voltage detection board, and the low-voltage direct current is transmitted to a direct current bus voltage signal acquisition circuit in an analog quantity mode through channels AO-1 and AO-2. The direct current bus voltage signal acquisition circuit acquires direct current bus voltage through analog quantity output channels AI-1 and AI-2.
Fig. 10 is a schematic diagram illustrating a connection between a shift control signal output circuit and a transformer according to an embodiment of the present invention, and as shown in fig. 10, 3 signal lines (DO-01, DO-02, and DO-03) of the shift control signal output circuit are connected to 3 signal lines (DI-01, DI-02, and DI-03) of a voltage regulating switch of the transformer.
As the dc voltage signal of the dc bus in the power conversion circuit is also a high voltage signal, in an optional implementation manner, the power supply circuit provided in the embodiment of the present invention may further include: and the direct current bus voltage detection board is connected between the direct current bus voltage signal acquisition circuit 103 and the direct current bus and used for converting the high-voltage direct current electric signal of the direct current bus into a low-voltage direct current electric signal of the controller 100.
Therefore, in an optional embodiment, the power supply circuit provided in the embodiment of the present invention may further include: the rectification control signal output circuit 104 is connected between the controller 100 and the rectifier 202, and is configured to transmit the rectification control signal output by the controller 100 to the inverter 203. Alternatively, the rectification control signal output circuit 104 transmits the rectification control signal output by the controller 100 to the inverter 203 through an optical fiber.
Fig. 11 is a schematic diagram illustrating a connection between a rectification control signal output circuit and a rectifier according to an embodiment of the present invention, and as shown in fig. 11, a control system controls the rectifier through 2 plastic optical fibers, Fib-Tx indicates a transmission signal optical fiber, and Fib-Rx indicates a reception signal optical fiber.
Preferably, in the power supply circuit provided in the embodiment of the present invention, the inversion control signal output circuit 102 transmits the inversion control signal output by the controller 100 to the inverter 203 through an optical fiber. Fig. 12 is a schematic diagram illustrating connection between an inverter control signal output circuit and an inverter according to an embodiment of the present invention, and as shown in fig. 12, a control system controls the inverter through 2 plastic optical fibers, Fib2-Tx indicates a transmission signal optical fiber, and Fib2-Rx indicates a reception signal optical fiber.
As can be seen from the above, in the arc power supply system according to the embodiment of the present invention, the power converter 20 composed of the transformer 201, the rectifier 202, and the inverter 203 converts the ac power of the ac power grid into the ac power required by the arc device, the arc voltage/current signal collecting circuit 101 in the control system 10 collects the voltage/current signal of the arc device 30, and the dc bus voltage signal collecting circuit 103 in the control system collects the dc voltage signal input from the rectifier 202 to the inverter 203 in the power converter; the controller 100 in the control system 10 outputs a control signal of the inverter 203, and the control signal is transmitted to the inverter 203 through the inverter control signal output circuit 102, so as to control the inverter 203 to output an alternating current signal, so that the alternating current signal meets the requirement of the arc equipment for continuously burning the arc. Therefore, the arc power supply system provided by the embodiment of the invention can provide the alternating current signal (for example, a trapezoidal wave alternating current signal) required by the arc equipment for stably burning the arc without connecting an inductor in series.
In an optional embodiment, the power supply circuit provided in the embodiment of the present invention may further include: a primary voltage/current signal acquisition circuit 105 connected between the controller 100 and the primary winding of the transformer 201, for transmitting a primary voltage/current signal of the transformer 201 to the controller 100; the secondary voltage/current signal acquisition circuit 107 is connected between the controller 100 and the secondary winding of the transformer 201, and is used for transmitting a secondary voltage/current signal of the transformer 201 to the controller 100; and the gear control signal output circuit 106 is connected to the controller 100 and connected to the voltage regulating switch of the transformer 201, and is used for transmitting the gear control signal output by the controller 100 to the voltage regulating switch.
Optionally, in the power supply circuit provided in the embodiment of the present invention, the primary voltage/current signal collecting circuit 105 includes: the second voltage/current transformer is connected between the controller 100 and the transformer 201 and is used for converting a high-voltage electric signal output by the primary side of the transformer 201 into a low-voltage electric signal required by the controller 100; the secondary voltage/current signal acquisition circuit 107 includes: and a third voltage/current transformer connected between the controller 100 and the transformer 201 and used for converting the high-voltage electrical signal output by the secondary side of the transformer 201 into a low-voltage electrical signal required by the controller 100.
It is noted that the primary voltage/current signal acquisition circuit 105 and the secondary voltage/current signal acquisition circuit 107 are implemented in the same manner as the arc voltage/current signal acquisition circuit 101.
The primary side voltage detection, the secondary side voltage detection and the arc voltage detection are consistent, and the second voltage transformer converts voltage signals Ua, Ub and Uc of the primary side high voltage of the transformer into low-voltage signals PT-A, PT-B, PT-C; the third voltage transformer converts the high-voltage signals Ua, Ub and Uc on the secondary side of the transformer into low-voltage signals PT2-A, PT2-B, PT 2-C.
Similarly, the primary side current detection, the secondary side current detection and the arc current detection are consistent, and the second current transformer converts the current signals Ia, Ib and Ic of the high voltage at the primary side of the transformer into current signals CT-A1, CT-A2, CT-B1, CT-B2, CT-C1 and CT-C2 of low voltage. (ii) a The third current transformer converts the high-voltage current signals Ia, Ib and Ic on the secondary side of the transformer into low-voltage current signals CT2-A1, CT2-A2, CT2-B1, CT2-B2, CT2-C1 and CT 2-C2.
The embodiment of the invention also provides an arc power supply, which is used for solving the technical problems that the existing arc power supply system is connected with an inductor in series in a power supply loop to provide alternating current for stable combustion of the arc, and the inductor causes the current in the power supply loop to have hysteresis so as to cause the total power factor of the power supply loop to be lower, the active loss to be larger and the power utilization efficiency to be lower, and comprises the following components: the arc power supply system based on the trapezoidal wave signal is described above. Because the principle of the embodiment of the arc power supply for solving the problem is similar to that of the arc power supply system based on the trapezoidal wave signal, the implementation of the embodiment of the arc power supply can refer to the implementation of the arc power supply system based on the trapezoidal wave signal, and repeated details are omitted.
It should be noted that the arc power supply provided by the embodiment of the present invention may be used for, but is not limited to, power supplies of arc-type electric devices such as an arc furnace and an electric welding machine.
It should be noted that the customized power supply provided by the embodiment of the present invention can satisfy the stable operation of the arc-type device, and the output voltage and current thereof are characterized as follows:
① unlike the AC sinusoidal waveform of a standard power supply, embodiments of the present invention use waveform modulation techniques to modulate the voltage waveform into one of rectangular, trapezoidal, or other curve-fitted alternating voltage waveforms proportional to the waveform required for arc combustion.
② is matched with the zero crossing point of the arc current, the zero crossing point of the alternating voltage waveform is controlled by du/dt, and the voltage waveform slope (trapezoid, other curve fitting voltage waveforms) is larger than the value required by the arc current continuity.
③ the amplitude of the output voltage meets the requirements for stable burning of the arc for the arc length.
④, the frequency of the alternating voltage waveform output by the power supply can be adjusted within the range of 10-100 Hz, and the requirements of minimum loss and optimal power factor of the loop are met.
⑤ the set current value is controlled to be constant, and the required arc power value is satisfied.
On the basis of researching the volt-ampere characteristics of the electric arc, the embodiment of the invention adopts a customized power supply technology, specially customizes a power supply for electric arc electric equipment, and meets the requirement of stable operation of the electric arc electric equipment.
In summary, the embodiments of the present invention provide a power supply system and a power supply for an arc device, in which a power converter is connected to an ac power grid through a rectifier transformer, and converts ac power of the ac power grid into ac power required by a rectifier, then converts the ac power into dc power through the rectifier, and converts the dc power output by the rectifier into ac power required by an arc device to burn an arc, and a control system controls an inverter in the power converter to output a trapezoidal wave voltage signal meeting an arc stable combustion condition, so that the ac power of the ac power grid can be converted into ac power required by the arc device to stably burn an arc, and the arc device can continuously burn an arc. Because the embodiment of the invention does not need to serially connect the inductor in the power supply loop, the problems that the overall power factor of the power supply loop is low, the active loss is increased and the power utilization efficiency is low due to the fact that the inductor is serially connected in the existing arc power supply circuit can be solved.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. An arc power supply system based on a trapezoidal wave signal, comprising: a control system and a power conversion circuit;
wherein the power conversion circuit comprises: a transformer, a rectifier and an inverter; the primary winding of the transformer is connected with an alternating current power grid; the secondary winding of the transformer is connected with the alternating current input end of the rectifier; the direct-current output end of the rectifier is connected with the direct-current input end of the inverter through a direct-current bus; the alternating current output end of the inverter is connected with the arc equipment;
the control system is connected with the power conversion circuit and the arc equipment respectively and used for collecting arc voltage or arc current of the arc equipment and controlling an inverter in the power conversion circuit to output a trapezoidal wave voltage signal meeting arc stable combustion conditions according to the arc voltage or the arc current of the arc equipment.
2. The arc power supply system of claim 1 wherein the control system controls an inverter in the power conversion circuit to output a voltage signal U during each voltage modulation cycle as follows:
wherein, t1The time when the arc current decays to zero in the last voltage modulation period; t is t2The moment when the arc current rises from zero to the forward maximum current value; t is t3The moment when the arc current starts to decay from the forward maximum current value; t is t4The moment when the arc voltage decays from the forward maximum voltage value to zero; t is t5The time when the arc current decays from the forward maximum voltage value to zero; t is t6The moment when the arc current decays from zero to a negative maximum current value; t is t7The time when the arc current starts to rise from the negative maximum current value is taken as the time; t is t8The moment when the arc voltage rises to zero from a negative maximum voltage value; t is t9At the moment when the arc current rises from the negative maximum current value to zero,
f is the frequency of the trapezoidal wave voltage signal.
3. The arc supply system of claim 1 or 2 wherein the control system is configured to control the position of the tap changer on the transformer such that the inverter outputs a trapezoidal wave voltage signal that satisfies arc stable combustion conditions.
4. The arc supply system of claim 3 wherein the control system is further configured to collect a primary voltage and a secondary voltage of the transformer and determine a position of a tap changer on the transformer based on the primary voltage and the secondary voltage of the transformer.
5. The arc power supply system according to claim 1 or 2 wherein the control system is configured to control the firing angle on-time of the rectifier such that the inverter outputs a trapezoidal wave voltage signal that satisfies arc stable combustion conditions.
6. The arc power supply system of claim 5 wherein the control system is further configured to collect the ac voltage at the ac input of the rectifier and the dc voltage at the dc output and determine the firing angle on-time of the rectifier based on the ac voltage at the ac input of the rectifier and the dc voltage at the dc output.
7. The arc power supply system according to claim 1 or 2, wherein the control system is configured to control a voltage duty ratio of the inverter output voltage signal such that the inverter outputs a trapezoidal wave voltage signal satisfying an arc-stabilized burning condition.
8. The arc power supply system of claim 7 wherein the control system is further configured to collect the dc voltage at the dc input of the inverter and the ac voltage at the ac output, and to determine the voltage duty cycle of the inverter output voltage signal based on the dc voltage at the dc input of the inverter and the ac voltage at the ac output of the inverter.
9. The arc power supply system of claim 1 wherein said control system is further configured to effect frequency adjustment of said inverter output voltage signal by changing a direction of said inverter output voltage signal.
10. An arc power supply, comprising: the trapezoidal wave signal-based arc power supply system of any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911162867.6A CN110957903A (en) | 2019-11-25 | 2019-11-25 | Arc power supply system and arc power supply based on trapezoidal wave signal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911162867.6A CN110957903A (en) | 2019-11-25 | 2019-11-25 | Arc power supply system and arc power supply based on trapezoidal wave signal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN110957903A true CN110957903A (en) | 2020-04-03 |
Family
ID=69978373
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911162867.6A Pending CN110957903A (en) | 2019-11-25 | 2019-11-25 | Arc power supply system and arc power supply based on trapezoidal wave signal |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110957903A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113267820A (en) * | 2021-05-27 | 2021-08-17 | 唐山学院 | Multi-frequency current zero-crossing waveform signal processing method and device |
-
2019
- 2019-11-25 CN CN201911162867.6A patent/CN110957903A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113267820A (en) * | 2021-05-27 | 2021-08-17 | 唐山学院 | Multi-frequency current zero-crossing waveform signal processing method and device |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8482935B2 (en) | Transformer-isolated switching converter | |
| CA2235776C (en) | An ac-dc power supply | |
| EP2506416B1 (en) | System and method for power conversion | |
| CN108696164A (en) | The single-phase photovoltaic grid-connected Miniature inverter of flyback and control method of DCM frequency control | |
| CN104811053A (en) | Control method for frequency-conversion power supply circuit starting process of magnetron | |
| CN109818501A (en) | With frequency-turn-on time converter controller | |
| CN110957903A (en) | Arc power supply system and arc power supply based on trapezoidal wave signal | |
| CN104917424A (en) | Motor internal contracting brake control system of construction elevator | |
| CN101510732B (en) | Control method for electron beam punching machine acceleration high-voltage power supply and power supply device | |
| CN109004836B (en) | Frequency conversion optimization control method suitable for modular multilevel direct current transformer | |
| CN211183806U (en) | Power supply circuit and power supply of arc equipment | |
| CN110912418B (en) | Electric arc power supply system and electric arc power supply based on strong excitation trapezoidal wave signal | |
| CN105141149B (en) | A kind of electron beam microfabrication equipments accelerating power source device and control method | |
| CN102468769B (en) | Communication system of alternating-current network | |
| CN110957904A (en) | Arc power supply system and arc power supply based on rectangular wave signal | |
| CN209845399U (en) | Variable-frequency dimmer based on Vienna PFC and full-bridge inverter circuit | |
| CN115388433B (en) | Electric ignition circuit and electric stove | |
| CN212413044U (en) | AC/DC power supply system | |
| CN101814850A (en) | Wide-frequency and low-voltage side trigger control method and device thereof for series connection thyristor valve unit | |
| CN103746569A (en) | High-power-factor constant-voltage constant-current programmable switching power supply and power supply method | |
| CN111438425B (en) | Multifunctional pulse arc welding power supply | |
| CN106452121A (en) | Adjustable excitation power supply of electric vibration table | |
| RU2156024C1 (en) | Three-phase sine-voltage regulator with high- frequency section | |
| CN202617030U (en) | Multi-level photovoltaic grid connected inverter with isolation transformer | |
| CN105717388A (en) | Transformer test platform |
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 |