EP2155430A1 - Procédé et dispositif pour réguler une source de courant et source de courant pourvue d'un tel dispositif - Google Patents

Procédé et dispositif pour réguler une source de courant et source de courant pourvue d'un tel dispositif

Info

Publication number
EP2155430A1
EP2155430A1 EP08716465A EP08716465A EP2155430A1 EP 2155430 A1 EP2155430 A1 EP 2155430A1 EP 08716465 A EP08716465 A EP 08716465A EP 08716465 A EP08716465 A EP 08716465A EP 2155430 A1 EP2155430 A1 EP 2155430A1
Authority
EP
European Patent Office
Prior art keywords
measuring
integration
value
capacitor
power
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.)
Withdrawn
Application number
EP08716465A
Other languages
German (de)
English (en)
Inventor
Birger Jaeschke
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Lorch Schweisstechnik GmbH
Original Assignee
Lorch Schweisstechnik GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Lorch Schweisstechnik GmbH filed Critical Lorch Schweisstechnik GmbH
Publication of EP2155430A1 publication Critical patent/EP2155430A1/fr
Withdrawn legal-status Critical Current

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
    • 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

Definitions

  • the invention relates to a method for controlling the current source of a welding, cutting or plasma coating system, wherein the current source comprises a measuring part and a controllable clocked power unit and wherein by means of the measuring part determines a measure that represents a measure of a characteristic to be controlled characteristic of the power unit , and the measure used to control the power unit.
  • Electrical welding equipment as well as electrical cutting equipment and plasma coating equipment, includes a power source having a power section that provides a controllable output voltage or current, or allows combined control of output current and output voltage.
  • a welding electrode can be connected to the power unit via an electric cable to form an arc between the welding electrode and a workpiece to be welded.
  • a controllable output voltage or a controllable output current can be provided in the case of plasma coating systems by means of the clocked power part, so that a plasma for coating a workpiece can be generated within a coating chamber.
  • the clocked power unit can be connected to its power supply to a supply network. In many cases, the power unit has a transformer and electrical converters.
  • the power unit in many cases includes electrical components for smoothing output current and / or output voltage.
  • electrical components for smoothing output current and / or output voltage.
  • internal impedances are used, in particular coils and resistances.
  • the electric cable which can be connected to the power unit forms external impedances and external ohmic resistances, just like the welding electrode and the arc or the plasma electrode and the electrical discharge in the coating chamber. It is desirable to detect the voltage dropping across the arc or the electrical discharge as quickly and accurately as possible for a process control. This voltage can be calculated from the output voltage of the clocked power section taking into account the external impedances and ohmic resistances.
  • the output voltage, the output current or the output power of the clocked power unit represent parameters of the power unit, which are usually controlled by a control part, for example, time-dependent or in response to certain process conditions.
  • a control part for example, time-dependent or in response to certain process conditions.
  • Measured value determined, which is then used to control the power part.
  • a time average of the parameter to be controlled can be determined as the measured value.
  • the parameter is usually subject to fluctuations over time due to changes in the external circuit connected to the power unit.
  • the arc voltage can fluctuate greatly depending on the process due to arc length changes and due to the occurrence of short circuits between the welding electrode and the workpiece to be welded or due to the break of the arc.
  • These fluctuations in turn affect the output voltage of the pulsed power part, which is also characterized by periodic Changes due to the clocked operation of the power unit distinguishes.
  • the object of the present invention is to refine a method of the type mentioned at the outset so that a measure of the parameter to be controlled can be determined within a short time.
  • This object is achieved in a method of the type mentioned in the present invention by applying a correlated with the controlled characteristic of the power part electrical measured variable starting from a predetermined initial value over a predetermined integration time whose duration of one or more clock periods of the clocked power unit speaks, at least approximately integrated and determined from the thus obtained integration value the dimensional value, this process is repeated continuously.
  • an electrical parameter for example, an electrical voltage or an electric current can be used.
  • the integration time is a single or a multiple of a single clock period of the clocked power part.
  • the parameter to be controlled is the output voltage
  • the parameter to be controlled has periodic fluctuations corresponding to the clock frequency of the clocked power unit, whose period corresponds to the clock period of the clock frequency.
  • the integration of the measured variable is carried out over an integration time whose duration corresponds to one or an integer multiple of a clock period. It can therefore be provided, for example, that the measured variable is integrated exactly over a single clock period and the measured value determined from the thus obtained integration value, which in turn is used to control the power part.
  • This integration process is repeated continuously, so that a current integration value is continuously available, from which a measured value can be currently determined. It can be achieved by a very fast control of the characteristic, so that even short-term fluctuations of the characteristic can be effectively counteracted.
  • the temporally synchronized to the clock of the power unit integration of the measured variable has the particular advantage that the caused by the timing of the power unit temporal changes of the characteristic can be filtered out in time insofar as these temporal changes are not considered as interference influences, by appropriate control of the Power parts must be compensated.
  • the determination of the measured value from the obtained integration value can be effected, for example, by multiplying the integration value by the inverse of the integration time, so that the measured value represents the time average of the measured variable correlated with the parameter of the power component.
  • the integration value itself is used as the measured value, since it represents a measure of the parameter to be controlled with a constant integration time.
  • the measured variable is at least approximately integrated in an isochronous manner over one or more clock periods of the clocked power part. The integration of the measured variable thus takes place in time with the power part.
  • the integration time is one or an integral multiple of a clock period.
  • the measured variable is at least approximately integrated in an isochronous manner over a single clock period of the power part. This allows a particularly fast control of the characteristic.
  • the integration value is determined by means of the measuring part, then the detected integration value is interrogated, stored in an intermediate memory and then the measuring part is reset to the initial value for a new determination of an integration value.
  • an integration value is determined periodically, which is initially stored in an intermediate memory and can then be used to determine the dimensional value, which in turn is included in the control of the power component.
  • the measuring part is reset to the initial value, for example to the value 0, so that then with a defined predetermined initial value a re-integration over a predetermined integration time can be performed, the integration value of the duration of one or more clock periods of the clocked Power parts corresponds.
  • the detected integration value is interrogated by the measuring part within one or more clock periods of the clocked power part, and the measuring part is buffered resets to the initial value and then determines isochronous again a new integration value.
  • the interrogation and buffering of the integration value and the resetting of the measuring part take place according to the timing of the power part.
  • a measuring part is provided with at least two measuring elements, with the aid of which an integration value is determined alternately, whereby during the time in which an integration value is determined by means of a first measuring element, the integration value previously determined by the second measuring element is interrogated and buffered and resets the second measuring element to the initial value.
  • This has the advantage that an updated integration value is continuously available and at the same time a new integration value is determined.
  • the respective integration values of the two measuring elements can be combined in a downstream signal processing unit, for example, an average of the two integration values can be determined, which can then again represent a measure of the parameter to be controlled.
  • the measuring voltage is alternately integrated at least approximately alternately via clock periods of the clocked power section which are in each case directly following one another.
  • This has the advantage that a current integration value is available after each clock period.
  • the clock frequency of the power part is thus used to determine the integration, query and reset time of the measuring part. This enables in particular an isochronous integration of the measured variable, an isochronous interrogation of the integration value and also an isochronous reset of the measuring part to the predetermined initial value of the integration.
  • An at least approximate integration of the measured variable can be carried out, for example, by using a capacitor which is connected in series with an ohmic resistor, wherein the charging voltage applied to the capacitor is periodically interrogated, the capacitor subsequently discharged and then carried out a new integration ,
  • the capacitor is charged in such a configuration via the ohmic resistance of an applied to the series circuit of ohmic resistance and capacitor voltage.
  • the charging voltage applied to the capacitor can be chosen to be significantly lower than the amplitude value of the voltage applied to the series connection, so that an approximate integration is achieved.
  • the capacitor is discharged by external switching means back to the desired initial value of the voltage.
  • the initial value of the voltage is advantageously a value close to zero, because then the capacitor via an electronic switch, for example, a MOSFET, can be easily discharged. It can also be provided that, for at least approximate integration, integrating analog-to-digital converters are used, which are synchronized with the clock frequency of the power unit.
  • an analog-to-digital converter which generates a continuous digital data stream from which the integration value is formed by addition or by at least approximating integrating digital filtering over the integration time.
  • a digital 1-bit A / D converter With the aid of a digital 1-bit A / D converter, a sequential data stream of logical zeros and ones can be generated from the signal to be measured.
  • This data stream can be supplied via controllable switching elements to at least one numerically sum-forming accumulation element, which adds up the sequential data stream over a specific integration time and thus forms the integration value. After expiration of the predetermined integration time, the accumulation element is reset to an initial value by means of further controllable switching elements.
  • the numerically formed integration value can be stored via controllable switching elements as a result of the integration in a buffer for further data processing. From the buffer, the integration value may be provided, for example, to a control part of the power source.
  • the structure of at least one numerically summing accumulation element fed by an analog-to-digital converter with a sequential data stream is often referred to as a "sigma-delta converter", and the analog-to-digital converter is used in conjunction with controllable switching - or transmission elements also referred to as "sigma-delta modulator".
  • Such structures are preferably realized in the form of programmable electronic circuits.
  • An at least approximate integration of the measured variable can also be achieved by scanning it at high frequency, for example with a sampling frequency which corresponds to one thousand times the clock frequency of the power part, and adding the probe results numerically.
  • microelectronic circuit is used for the at least approximate integration. This allows a particularly compact design of the power source.
  • the interrogation and buffering of a determined integration value take place with the aid of a sample-and-hold circuit.
  • sample and hold circuits Such circuits are also known as “sample and hold circuits”.
  • an integration value can be briefly stored in a buffer, so that the measuring part can be reset immediately after integration back to the desired initial value of the integration.
  • the buffered integration value can then be supplied, for example, to an analog-to-digital converter which is in electrical connection with a control part of the current source.
  • the output voltage of the power section can be used as the parameter to be controlled.
  • the output voltage itself can be used.
  • an internal voltage of the power part is used as the measured variable, the internal voltage representing an image of the output voltage.
  • the power section smoothing elements in particular inductances and Ohm 1 - comprises specific resistances and that one uses as a measure of the elements to the smoothing applied voltage.
  • the output current of the power unit As a parameter to be controlled, it is also possible to use the output current of the power unit. If the power source is used in a welding system, it is possible, for example, to use the welding current as a parameter. This also has temporal variations that correspond to the timing of the power part.
  • the method according to the invention also makes possible here a very fast and very accurate determination of a dimensional value which represents a measure of the welding current to be regulated.
  • the welding current can be conducted via a measuring resistor, at which a voltage correlated with the welding current drops, which can then be integrated in the above-mentioned manner. It can also be provided that the welding current with the help of a current transformer to a smaller
  • Measuring current converts, which then integrates. For example, by means of the measuring current, it is possible to charge a capacitor whose charging voltage then forms the integration value.
  • the invention also relates to a device for carrying it out, the device having a measuring part which comprises a measuring circuit with at least one triggering device.
  • a measurable measuring element wherein by means of the measuring element continuously repetitively a measured variable can be integrated at least approximately starting from a predetermined initial value over a predetermined integration time.
  • a measured variable which is correlated with a characteristic to be controlled characteristic of the power of a power source, starting from a predetermined initial value over a predetermined integration time whose duration corresponds to one or more clock periods of the clocked power part, and from the thus obtained
  • the integration value can then be determined in the aforementioned manner of the desired value for controlling the parameter.
  • the measuring circuit has at least two triggerable measuring elements, wherein the measured variable can be at least approximately integrated alternately over predetermined integration times by means of the measuring elements.
  • a current integration value can be continuously provided by the alternating integration of the measured variable by means of the two measuring elements.
  • the measuring part in a preferred embodiment of the device according to the invention on at least one sample-and-hold circuit, which is arranged downstream of the measuring circuit.
  • a plurality of sample-and-hold circuits, each connected to a measuring element are used, so that the integration value provided by a measuring element can be temporarily stored in the associated sample-and-hold circuit, in order subsequently to receive it an analog-digital Feed converter.
  • the measuring circuit has at least one clock input, which can be acted upon by an external clock frequency.
  • the at least one triggerable measuring element comprises a capacitor which is connected in series to an ohmic resistance, and an interrogator, wherein the charge voltage applied to the capacitor is interrogated periodically by the interrogator and wo- at the capacitor after the query to a predetermined initial value is discharged.
  • this allows an approximate integration of a measured variable in the form of an electrical voltage, since this provides the capacitor via the ohmic resistance charging current, so that the capacitor is charged to a charging voltage that can be queried by the interrogator.
  • the charging voltage can be kept considerably smaller by appropriate dimensioning of the ohmic resistance and the capacitor than the amplitude value of the voltage applied to the series circuit of ohmic resistor and capacitor electrical voltage, so that an approximate integration can be achieved.
  • the capacitor is discharged by external switching means back to the initial value of the charging voltage. It is advantageous here as the initial value of the voltage, a value close to zero, because then the capacitor via an electronic switch, for example a MOSFET, can be easily discharged.
  • the at least one triggerable measuring element of the measuring circuit comprises an analog-to-digital converter, which can be connected to an can be synchronized clock frequency. This allows a very accurate integration of the measurement voltage.
  • the at least one triggerable measuring element comprises an analog-to-digital converter, which is connected via controllable or logical switching or transmission elements with a sum-forming accumulation element, wherein by means of the accumulation element from a system digital converter provided continuous data stream over the integration time can be summed up.
  • the accumulation element can be reset to an initial value by means of logic or controllable switching or transmission elements, and the accumulation value provided by the accumulation element after expiration of an integration time can preferably be provided to an intermediate memory whose output can be connected to a control part.
  • the at least one triggerable measuring element has a synchronizable operational amplifier.
  • the measuring circuit is preferably designed as a microelectronic circuit. It is particularly advantageous if the entire measuring part is designed as a microelectronic circuit.
  • the device according to the invention is used in particular for power sources for welding systems, cutting systems or plasma coating systems.
  • the invention therefore also relates to a power source for a welding or cutting system or a plasma coating system, comprising a control part, a clocked power unit and a device of the above-mentioned.
  • the device can be connected between an output line of the power unit and a ground line and connected to a control input of the control part, so that a value determined by the device via the control input to the control part can be entered to control the clocked power part.
  • a clock input of the device may be connected to a clock output of the control part, so that the device with the clock frequency of a clock generator of the control part can be acted upon.
  • the clocked power unit may have switching elements that allow a controlled change in the polarity of the output voltage and / or the output current of the power unit.
  • the measuring circuit can have measuring elements for the separate, at least approximate integration of positive and negative current or voltage values.
  • the measured value detection is preceded by converters which always convert the current or voltage value to be detected into the polarity detectable by at least one measuring element.
  • FIG. 1 shows a schematic representation of a power source according to the invention for a welding system
  • FIG. 2 shows a first embodiment of a measuring part of the current source from FIG. 1;
  • 3A to 3G voltage curves and switching states for explaining the measuring part from FIG. 2;
  • FIG. 5 shows a third embodiment of a measuring part of the current source from FIG. 1.
  • FIG. 1 schematically shows a welding power source 10 according to the invention with a clocked power section 12 that can be controlled by a control section 14.
  • the Steuererrteil 14 has a clock generator 15 for generating a clock frequency, which is the clocked power section 12 is provided.
  • control unit 17 To the control part 14, a control unit 17 is connected.
  • the control panel has several known per se and therefore not shown in the drawing controls, via which the welding power source 10 can be operated by the user.
  • the clocked power section 12 is connected via an output line 19 to a voltage output 20 of the welding power source 10, and via a ground line 22, the clocked power section 12 is connected to a ground output 23 of the power unit 12.
  • the welding power source 10 is used in electric welding systems.
  • an electric cable 25 can be connected to the voltage output 20, which carries a welding torch 26 at its free end.
  • a ground cable 28 can be connected on the one hand to the ground output 23 of the welding power source 10 and on the other hand to a workpiece 29 to be welded.
  • the welding power source 10 via a known per se and therefore not shown in the drawing supply cable to a likewise not shown in the drawing energy supply network, in particular a public utility network, for example, a 230 V or 400 V AC mains are connected.
  • an arc 31 can be generated between the welding torch 26 and the workpiece 29 for welding the workpiece 31.
  • the electric cable 25 forms an outer in combination with the welding torch 26, the arc 31, the workpiece 29 and the ground line 28
  • the power section 12 also has impedances and ohmic resistances, which are smoothing elements for smoothing the output voltage provided by the power section 12.
  • These internal smoothing elements are in Figure 1 simplified by the internal impedance of 36 ohms and the internal 1 - illustrates's resistance 37th
  • a parameter of the clocked power part 12 represents the output voltage applied between the output line 19 and the ground line 22.
  • the output voltage can be controlled by the control part 14 to achieve an optimum welding result.
  • the welding power source 10 has a switched between the output line 19 and the ground line 22 measuring part 40, which is explained in more detail below and is only schematically dargterrorism in Figure 1.
  • the measuring part 40 is connected via a control line 41 to a control input 42 of the control part 14, and via a clock line 44 is a clock input 45 of the measuring part 40 with a clock output 46 of the control part 14 in electrical connection.
  • the clock frequency of the clock generator 15 can be provided to the measuring part 40, and via the control line 41, the control part 14 for controlling the power unit 12, a harmonicwert be provided which represents a measure of the output voltage of the clock generator 15 to be controlled.
  • the measuring part 40 is shown in simplified form in FIG. It comprises, in addition to the clock input 45, a signal input 48 and a ground input 49, which are connected to one another via an ohmic resistor 52 and a Zener diode 53.
  • a first capacitor 57 is connected in parallel with the zener diode 53 via a first electronic switch 56, and a discharge resistor 60 is connected in parallel to the first capacitor 57 via a second electronic switch 59.
  • Parallel to the Zener diode 53, a second capacitor 63 is also connected via a third electronic switch 62, which can also be discharged via the discharge resistor 60 via a fourth electronic switch 65.
  • the first capacitor 57 forms a first measuring element of the measuring part 40 and the second capacitor 63 forms a second measuring element.
  • the ohmic resistor 52, the Zener diode 53 and the two capacitors 57 and 63 with the common discharge resistor 60 and the four switches 56, 59, 62 and 64 form a measuring circuit 67 of the measuring part
  • the voltage applied to the first capacitor 57 voltage can be tapped from a first sample-and-hold circuit 69 which is connected to an analog-to-digital converter 71.
  • the voltage applied to the second capacitor 63 voltage can be tapped via a second sample-and-hold circuit 73, which is also in communication with the analog-to-digital converter 71.
  • the output of the analog-to-digital converter 71 is connected via the already explained control line 41 to the control input 42 of the control part 14 in connection, and the two inputs 48 and 49 can be connected to the output line 19 and the ground line 22.
  • the output voltage of the power section 12 can be applied to the inputs 48, 49 of the measuring part 4.
  • the first switch 56 is closed and at the same time the third switch 62 is opened, starting from the signal input 48, a current can flow via the ohmic resistor 52 and the first capacitor 57, which results in the first capacitor 57 charging , Will the first switch 56 opened and the second switch 59 is closed, the first capacitor 57 can discharge via the discharge resistor 60.
  • the second capacitor 63 can be charged, which can be discharged by opening the third switch 62 and closing the fourth switch 65 via the discharge resistor 60.
  • the ohmic resistor 52 and the two capacitors 57 and 63 are dimensioned such that the charging voltage applied to the capacitors 57 and 63 remains significantly smaller than the amplitude value of the applied to the inputs 58 and 59, the measured variable with the output voltage of the power unit 12th is identical.
  • FIG. 3A schematically shows the time profile of the output voltage of the clocked power part 12.
  • this output voltage represents the parameter of the welding current source 10 to be controlled.
  • the clock of the power part 12 is shown in the output voltage in periodic fluctuations, which are shown in FIG regular intervals, namely with the clock period P are illustrated.
  • the switching position of the first electronic switch 56 is shown schematically in FIG. 3B, with the first switch 56 in this figure having S1. is drawing. It changes its switching position in successive periods.
  • the first electronic switch 56 is closed, during the immediately following second clock period P2 it is open, and then again assumes its closed switching state in the third clock period.
  • the fourth clock period P4 it is then opened again. This process is repeated continuously.
  • the switching position of the second electronic switch 59 is shown schematically in Figure 3C, wherein the second electronic switch 59 is designated in this figure with S2. It assumes its open switching position during the first clock period P1 and the first half of the second clock period P2, then is closed during the second half of the second clock period P2, and then its open switch position during the third clock period P3 and the first half of the fourth clock period P4 take. This switching process is repeated continuously.
  • the switching position of the third electronic switch 62 is shown schematically in FIG. 3B, this switch being designated S3 in FIG. 3D. He takes each of the first electronic switch 56
  • Engine-set switching position He takes each of the first electronic switch 56
  • the third electronic switch 62 is open, during the second clock period P2 it is closed, during the third clock period it is open again, and this change of switching position continues periodically.
  • the switching position of the fourth electronic switch 65 is shown schematically in Figure 3E, where it is denoted by S4 in this figure. He takes his open during the second half of the first clock period Switching on, and is closed during the second clock period and the first half of the third clock period. Then it is open during the second half of the third clock period, and then again assume its closed switching position.
  • FIG. 3F schematically shows the time profile of the charging voltage applied to the first capacitor 57. Since the first switch 56 is closed during the first clock period Pl and the third switch 62 is open, the first capacitor 57 charges continuously during the first clock period Pl. After the first clock period Pl, the first switch 56 is closed, so that the charge voltage applied to the first capacitor 57 during the first half of the second period P2 practically maintains a constant value until the second switch 59 after the first half of the second clock period Pl is closed. By closing the second switch 59, the first capacitor 57 is discharged during the second half of the second clock period P2.
  • the charging and discharging process is repeated, because during the third clock period P3, the first switch 56 is closed, the third switch 62 is open and also the second switch 59 assumes its open switching position.
  • the first capacitor 57 can therefore recharge, then retains its charging voltage during the first half of the fourth clock period P4, in order subsequently to be discharged again by opening the second switch 59.
  • the charging voltage applied to the first capacitor 57 is interrogated during the first half of the second clock period P2 by the first sample-and-hold circuit 59 and buffered in the usual way, in order to then supply the analog-digital
  • the first half of the second clock period P2 thus forms a data acceptance interval D1 for the integration value, which was determined by the approximate integration during the first clock period Pl.
  • the first capacitor 57 is discharged, so that it again has its initial charging voltage of approximately 0 V at the beginning of the third clock period P3 and a renewed integration can be carried out.
  • FIG. 3G the time course of the voltage applied to the second capacitor 63 charging voltage is shown schematically.
  • the time profile largely corresponds to that of the charging voltage of the first capacitor 57, however, the charging voltage of the second capacitor 63 is offset by one clock period with respect to the time course of the charging voltage of the first capacitor 57.
  • the third electronic switch 62 is opened and by closing the fourth electronic switch 65 during the second half of the first clock period Pl, the second capacitor 63 is discharged.
  • the third switch 62 is closed during the second clock period P2, whereas the fourth electronic switch 65 assumes its open switching position.
  • the second capacitor 63 is charged alternately with the first capacitor 57.
  • the second capacitor 63 While the data transfer takes place on the first capacitor 57 and then the reset of the first capacitor 57 to the initial value of its charging voltage, the second capacitor 63 is charged. After expiration of the second clock period P2, the third switch 62 is opened again, so that during the first half of the third clock period P3 the charging voltage applied to the second capacitor 63 can be interrogated by the second sample-and-hold circuit 73. The first half of the third clock period P3 thus forms a data acceptance interval D2 for the second capacitor 63. Subsequently, the second capacitor 63 becomes during the second half the third clock period P3 discharged by the fourth switch 64 is closed. Thus, during the second half of the third clock period P3, the charging voltage of the second capacitor 63 is reset to the initial value of approximately 0V. During the fourth clock period P4, the second capacitor 63 is then recharged by opening the first switch 56 and closing the third switch 62.
  • the clock processing unit 75 is thus part of the measuring circuit 67.
  • the clock processing unit 75 is integrated in the control part 14, which then controls the electronic switches 56, 59, 62 and 65 directly synchronously with the clock frequency of the power section 12.
  • the respective integration value is used to form the time average. Subsequently, the deviation of the mean value determined by the measuring part 40 to the mean value of the applied calibration voltage is determined and a corresponding correction value is stored in the control part 14. During ongoing operation, a correction can thus be made by the control part 14, so that the control part 14 by the use of the measuring part 40 continuously present a current actual value of the output voltage of the clocked power section 12. This actual value can be compared in the usual way with a desired value specified by the user by means of the operating part 17 for controlling the output voltage of the clocked power part 12.
  • the second embodiment of a measuring part is assigned the reference numeral 80 in FIG.
  • the measuring part 80 comprises a measuring circuit 82 and an interrogator in the form of a sample-hold circuit 83 and an analog-to-digital converter 84 which is connected to the output of the sample-and-hold circuit 83 and the output side via the control line 41 to the control input 42 of the control part 14 is in communication.
  • the measuring circuit 82 includes a clock processing unit 85.
  • the measuring circuit 82 has a signal input 86 and a ground input 87 and an output 88.
  • the first input 86 is connected via an Ohm 1 - specific resistor 81 and a first electronic changeover switch 89 al ternatively with a first measuring element in the form of a first operational amplifier 90 or with a second measuring element in the form of a second operational amplifier 91 in electrical connection.
  • the outputs of the two operational amplifiers 90, 91 are connected via a second electronic changeover switch 93 to the output 88 of the measuring circuit 82.
  • the two operational amplifiers 90, 91 each have two amplifier inputs, wherein in each case one amplifier input is connected to the first changeover switch 89 and the second amplifier input is connected to ground.
  • the output of the first operational amplifier 90 is connected via a first capacitor 95 to the first amplifier input and, in a corresponding manner, the output of the second operational amplifier 91 is connected via a second capacitor 96 to the first amplifier input of the second operational amplifier 91 in electrical connection.
  • the first capacitor 95 can be bridged by a first electronic switch 98 and the second capacitor 96 can be bridged by a second electronic switch 99.
  • a measured value can be applied to the inputs 86, 87, for example in the form of the output voltage of the clocked power part 12. This measured variable can then be used alternately in immediately successive clock periods of the output voltage by means of the two operational amplifiers 90, 91 and the capacitors 95, 96 corresponding opening and closing of the switches 98, 99 and changing the switching position of the changeover switches 89 and 93 are integrated.
  • the control of the switches 98, 99 and the changeover switches 88, 89 takes place by means of the clock processing unit 85, which forms a constituent part of the measuring circuit 82, but which could also be integrated in the control part 14.
  • the respective integration value provided by the operational amplifiers 90, 91 may be provided by the sample and hold circuit 83 be queried via the second changeover switch 93 and temporarily stored in memory, to then be supplied to the analog-to-digital converter 94.
  • a digital signal provided by the analog-digital converter 94, which corresponds to the respective integration value, can then be transmitted via the control line 41 to the control part 14, as has been explained in more detail above with reference to FIG.
  • the measuring part 40 shown in FIG. 2 in this case only allows an approximate integration, whereas with the measuring part 80 a real integration of the measuring voltage applied to the inputs 86, 87 can be carried out.
  • the measuring part 80 thus enables rapid control of the output voltage of the clocked power unit 12, as is provided by isochronous integration and resetting each of the integration value to an initial value, a current measure of the output voltage of the power unit 12 to be controlled. Before the use of the measuring part 80, this can be calibrated just as was explained using the example of the measuring part 40.
  • a third embodiment of a measuring part is shown schematically in FIG. 5 and has the reference numeral 110 as a whole.
  • the measuring part 110 comprises a signal input 111 and a ground input 112.
  • the signal input 111 is followed by a 1-bit analog-digital converter 114, which is connected via a controllable switching element 116 to a numerically sum-forming accumulation element 118.
  • the latter can be controlled via a controllable switching element 120 by a clock processing unit 122, which is connected to a clock input 124 of the measuring part 110.
  • the output of the accumulation element 118 is connected via a further controllable switching element 126 to a latch 128 whose output is in electrical connection with the signal output 130 of the measuring part 110.
  • the signal output 130 can be connected via the already explained control line 41 to the control input 42 of the control part 14.
  • the signal input to be integrated is applied to the signal input 111.
  • the digital 1-bit analog-to-digital converter 114 generates from the measurement signal a sequential data stream of logical zeros and ones.
  • This data stream is supplied via the controllable switching element 116 to the numerically sum-forming accumulation element 118, which can be reset by the controllable switching element 120 to a predetermined initial value and which adds up the sequential data stream numerically over a predetermined integration time and thus forms the integration value.
  • This integration value is supplied via the controllable switching element 126 to the buffer 128, from which the integration value is provided to the control part 14 via the control line 41.
  • the control of the measuring part 110 via the clock processing unit 122, which is connected via the clock input 124 and the signal line 44 to the clock output 46 of the control part 14 in connection.
  • An approximate integration can also be achieved in the measuring part 110 in a simplified manner in that the controllable switching elements 116, 120 and 126 perform a digital filtering in conjunction with the buffer 128.
  • This filtering allows for an approximate integration.
  • the structure of numerical summation accumulation element 118, to which a sequential data stream is provided by 1-bit analog-to-digital converter 114, is generally referred to in the literature as a "sigma-delta converter", and the 1-bit Analog-to-digital converter 114 is also generally referred to as "sigma-delta modulator" in conjunction with controllable switching element 116.
  • these structures are realized in the form of programmable electronic circuits.
  • the output voltage of the clocked power section 12 can be used for the measuring parts 40, 80 and 110.
  • an internal voltage of the clocked power part 12 is used as the measured variable for the measuring parts 40, 80 and 110, in particular the voltage which the power part 12 has before its internal smoothing elements, ie before the internal impedance 36 and the internal ohm. resistance 38 is provided.
  • Such a circuit option is shown in phantom in FIG.
  • a measuring resistor can be connected in the output line 19 and the voltage drop occurring at this measuring resistor can be used as a measured variable for the measuring part 40, 80 or 110.
  • This measured variable can be at least approximately integrated in the same way as the output voltage of the power part 12 by means of the measuring parts 40, 80 or 110 so that a standard value can also be provided which is a measure of the parameter to be controlled, in this case a measure for the output current to be controlled of the clocked pulse tion parts 12, represents.
  • a standard value can also be provided which is a measure of the parameter to be controlled, in this case a measure for the output current to be controlled of the clocked pulse tion parts 12, represents.
  • Such a use of the measuring parts 40, 80 and 110 is shown in dashed lines in Figure 1.
  • the welding current is converted by means of a current transformer to a measuring current with a smaller amplitude and integrated the measuring current, for example, such that one charges a capacitor whose charging voltage then forms the integration value, which in turn is a measure of the welding current to be controlled represents.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Mechanical Engineering (AREA)
  • Inverter Devices (AREA)
  • Measurement Of Current Or Voltage (AREA)
  • Measurement Of Resistance Or Impedance (AREA)

Abstract

L'invention concerne un procédé pour réguler la source de courant d'une installation de soudage, de coupe ou de revêtement plasma, cette source de courant comprenant un élément de mesure et un élément de puissance cadencé régulable. L'élément de mesure permet de déterminer une valeur de mesure représentant une grandeur pour un paramètre caractéristique de l'élément de puissance devant être régulé, cette valeur de mesure étant utilisée pour réguler l'élément de puissance. L'objectif de l'invention est de perfectionner ce procédé de sorte qu'il permette de déterminer une mesure pour le paramètre caractéristique à réguler en un temps réduit. À cet effet, une grandeur de mesure en corrélation avec le paramètre caractéristique de l'élément de puissance devant être régulé est intégrée au moins approximativement à partir d'une valeur de départ prédéterminée pendant un temps d'intégration prédéterminé, dont la durée correspond à une ou plusieurs périodes élémentaires de l'élément de puissance cadencé, et la valeur de mesure est déterminée à partir de la valeur d'intégration ainsi obtenue, cette opération étant répétée en continu. L'invention concerne en outre un dispositif pour mettre en oeuvre ce procédé et une source de courant pourvue d'un tel dispositif.
EP08716465A 2007-06-12 2008-03-12 Procédé et dispositif pour réguler une source de courant et source de courant pourvue d'un tel dispositif Withdrawn EP2155430A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102007028160.0A DE102007028160B4 (de) 2007-06-12 2007-06-12 Verfahren und Vorrichtung zur Steuerung einer Stromquelle sowie Stromquelle mit einer derartigen Vorrichtung
PCT/EP2008/001959 WO2008151681A1 (fr) 2007-06-12 2008-03-12 Procédé et dispositif pour réguler une source de courant et source de courant pourvue d'un tel dispositif

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EP2155430A1 true EP2155430A1 (fr) 2010-02-24

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EP08716465A Withdrawn EP2155430A1 (fr) 2007-06-12 2008-03-12 Procédé et dispositif pour réguler une source de courant et source de courant pourvue d'un tel dispositif

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US (1) US8153932B2 (fr)
EP (1) EP2155430A1 (fr)
CN (1) CN101678494B (fr)
DE (1) DE102007028160B4 (fr)
WO (1) WO2008151681A1 (fr)

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JP5052586B2 (ja) * 2009-11-18 2012-10-17 株式会社豊田中央研究所 抵抗溶接方法、抵抗溶接部材、抵抗溶接機とその制御装置、抵抗溶接機の制御方法とその制御プログラム、抵抗溶接の評価方法とその評価プログラムおよび抵抗溶接の溶融開始時の検出方法
JP2013151012A (ja) * 2012-01-26 2013-08-08 Daihen Corp 溶接電源の保護制御方法
US10022889B2 (en) 2013-03-14 2018-07-17 Stratasys, Inc. Ceramic support structure
DE102015116171B4 (de) 2015-09-24 2018-03-08 Rehm Gmbh & Co. Kg Schweißgerät und Verfahren zum Betreiben desselben

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US20060226131A1 (en) * 2005-04-11 2006-10-12 Lincoln Global, Inc. System and method for pulse welding

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Also Published As

Publication number Publication date
CN101678494A (zh) 2010-03-24
US20100133249A1 (en) 2010-06-03
DE102007028160A1 (de) 2008-12-18
CN101678494B (zh) 2012-12-26
DE102007028160B4 (de) 2019-07-11
US8153932B2 (en) 2012-04-10
WO2008151681A1 (fr) 2008-12-18

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