Process for resistance welding arrangement for carrying out the process
AssigneeElpatronic AG
InventorsHubert Schuermann, Werner Sutter, Markus Weber
Life of this patent
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Abstract
A process and apparatus for resistance-welding produce a welding current which pulsates in periodic half-waves, in particular an alternating current. The, welding current is generated from a primary alternating voltage which is chopped n times (n>1) in each half-wave and pulse width modulated in order to regulate the welding current. A regulator is provided and has a storage device containing the current nominal values for each chopping interval, corresponding to the welding current form, for comparison with each actual current value determined in each chopping interval.
Claims31
Process for resistance welding with a welding current which pulsates in periodic half-waves and which is generated from a primary alternating voltage and is controlled by pulse length modulation thereof, characterized in that the primary alternating voltage during the pulse length modulation is chopped in each half-wave with a chopping frequency and wherein the welding current is controlled within the half-wave on the basis of a nominal-actual value comparison by influencing the duty ratio in accordance with the pulse length modulation, and said chopping frequency is n-times the welding current frequency, n being a number greater than 1, and wherein a sequence of welding current nominal values is provided to define the form of each half-wave, and in each half-wave n nominal-actual comparisons of the welding current are performed and in each half-wave the duty ratio is influenced n times.
Process for resistance-welding with a welding current pulsating in periodic half-waves which current is generated from a primary alternating voltage, characterized in that the primary alternating voltage is chopped into pulses in each half-wave with a chopping frequency which is a multiple of the welding current frequency, and the pulses are pulse width modulated in order to produce a particular welding current which deviates from a sinusoidal profile and wherein the welding current is controlled within the half-wave on the basis of a nominal-actual value comparison, by influencing the duty ratio in accordance with the pulse width modulation, and wherein said chopping frequency is n-times the welding current frequency, n being a number greater than 1, and wherein a sequence of welding current nominal values is provided to define the form of each half-wave, and wherein in each half-wave n nominal-actual comparisons of the welding current are performed and in each half-wave the duty ratio is influenced n times.
An arrangement for controlling the welding current in a resistance welding machine having a static frequency changer for generating a primary alternating voltage supplied to a welding transformer with the secondary circuit of the transformer connected to the welding electrodes of the machine, comprising:
- a chopper in the frequency changer for chopping each half-wave of the primary alternating voltage into a series of pulses;
- and
- control means connected with the chopper for controlling the pulses and welding current generated in each half-wave of the primary alternating voltage, the control means including a regulator which is connected to the chopper of the frequency changer for controlling the welding current by pulse length modulation of the primary alternating voltage, the control means having a welding current reference element including storage means for storing an ordered sequence of nominal current values corresponding to the form of welding current in each interval of the chopper voltage for comparing with each actual current value which is determined for each chopping interval.
Arrangement for controlling the welding current in a resistance welding machine, comprising:
- a static frequency changer which generates the primary alternating voltage (Up) and transmits it to a welding transformer whose secondary circuit is connected to welding electrodes of a resistance welding machine, the static frequency changer including a direct current intermediate circuit and a chopper as an output stage;
- a control device by means of which the chopper can be controlled for the multiple chopping of each half-wave of the primary alternating voltage, said control means having a welding current reference element including storage means in which a sequence of nominal current values corresponding to the form of welding current in each interval of the chopper voltage is stored for comparing with each actual current value which is determined for each chopping interval;
- and
- a comparator for comparing said actual current value with said nominal current value n-times within each half-wave of said welding current.
An arrangement for controlling the welding current in a resistance welding machine having a static frequency changer for generating a primary alternating voltage supplied to a welding transformer with the secondary circuit of the transformer connected to the welding electrodes of the machine, comprising:
- a chopper in the frequency changer for chopping each half-wave of the primary alternating voltage into a series of pulses;
- and
- control means connected with the chopper for controlling the pulses and welding current generated in each half-wave of the primary alternating voltage, the control means including a regulator which is connected to the chopper of the frequency changer for controlling the welding current by pulse length modulation of the primary alternating voltage, the control means having a welding current reference element including storage means which contains nominal current values corresponding to the form of welding current in each interval of the chopper voltage for comparing with each actual current value which is determined for each chopping interval.
Dependencies are inferred from the claim text.