Multi-source Capacitor Discharge Welding Device
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Solution Overview
Problem
Capacitor discharge welding (KE welding) is limited by its inability to switch off the welding current at a desired time, leading to interrupted processes, inability to perform multi-pulse welding, and high energy consumption, as the current flow is controlled by thyristors that cannot be extinguished once fired, resulting in rapid heating and cooling without adjustable process times.
Innovation Solution
A welding device with multiple power sources, each comprising a capacitor and a thyristor, alternately generates capacitor currents to control the welding current, allowing for sequential or simultaneous discharge of capacitors to manage the welding process, enabling uninterrupted multi-pulse welding and adjustable energy input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single capacitor bank is used for welding, then the welding process is simple, but multi-pulse welding is not possible and the process must be interrupted between pulses
Solution Approach 1:
The single capacitor bank is divided into multiple independent capacitor banks (first capacitor bank and second capacitor bank), each capable of being discharged independently to generate separate welding pulses. This segmentation enables multi-pulse welding capability while maintaining manageable system complexity through modular architecture.
Solution Approach 2:
The capacitor banks are configured to discharge in sequential periods, with the first capacitor bank discharging to generate a first welding pulse, followed by the second capacitor bank discharging to generate a second welding pulse. This periodic action enables continuous multi-pulse welding without interruption between pulses.
2Ease of operation
If thyristors are used to switch the welding current, then the circuit is simple, but the current cannot be switched off at a desired time
Solution Approach 1:
The system transitions from static thyristor switching to dynamic IGBT switching, where the insulated gate bipolar transistors can be turned on and off dynamically during the capacitor discharge process. This enables the welding current to be switched off at precisely desired times, providing adjustable process times and improved ease of operation.
Solution Approach 2:
The switching device changes from thyristors (which can only be turned on) to IGBTs (which can be turned on and off). This parameter change in the switching device capability enables bidirectional control of the welding current, allowing the process time to be adjusted by switching off the current at different moments during capacitor discharge.
3Productivity
If the capacitor discharges completely, then all energy is utilized, but the welding process must wait for capacitor recharging
Solution Approach 1:
While the first capacitor bank is discharging to generate a welding pulse, the second capacitor bank is simultaneously being recharged. This continuity of useful action ensures that when the first capacitor needs to be recharged, the second capacitor is already ready to generate the next welding pulse, eliminating idle waiting time and improving productivity.
Solution Approach 2:
The second capacitor bank is recharged in advance before it is needed for discharge. This preliminary action of recharging the second capacitor while the first is discharging ensures that the welding process can continue without interruption, reducing the loss of time during capacitor recharging cycles.
4Productivity
If high peak current is used for welding, then the welding speed is high, but the energy consumption increases
Solution Approach 1:
Instead of using a single high-energy pulse, the welding process uses multiple lower-energy pulses discharged sequentially from different capacitor banks. The first capacitor bank discharges to create a welding pulse, then the second capacitor bank discharges to create another pulse. This periodic action achieves the same welding effect with distributed energy input, reducing peak energy consumption while maintaining welding speed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for continuous welding over multiple pulses without interruption, reduces energy consumption, and provides flexible control over welding parameters, enabling longer post-pulses and improved partial load operation without increasing peak current.
Implementation Method 1
The welding current partially heats these parts to be joined to near the melting point
Implementation Method 2
When a thyristor fires, the charge on a capacitor, which is basically designed as a capacitor bank, is conducted via the electrodes through the parts to be joined
Implementation Method 3
A transformer can also be interposed
Data Source
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AI summary
The invention relates to a welding device for carrying out a capacitor discharge welding process in which a welding current (lw) is generated by discharging at least one capacitor, and the welding device has at least one first current source (10) for generating a first capacitor current (l1) for generating the welding current (lw), and the first current source (10) comprises - a first capacitor (C1) for providing electrical energy and - a first thyristor (Th1) for switching on the first capacitor current (l1) from the first capacitor (C1), wherein at least one second current source (20) is provided for generating a second capacitor current (l2) in order to generate the welding current (lw) or a part thereof alternately with the first current source (10), or to generate the welding current (lw) or a part thereof successively with the first and further current sources.