Resistance Welding Transformer Polarity Switching Against Magnetization
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Solution Overview
Problem
Resistance welding apparatuses face challenges such as magnetization of welded parts, erosion of welding electrodes, and material creep due to DC current and varying metal alloys, which complicates processing and increases costs.
Innovation Solution
A resistance welding apparatus with a welding tool, a welding transformer, and a series circuit of two transistors connected between the welding tool and the transformer, allowing for polarity-switchable welding voltage and current without additional cables, thus avoiding magnetization and reducing electrode erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a rectifier having four thyristors is used instead of a conventional diode rectifier to avoid magnetization effects, then magnetization of welded parts is avoided, but the structural space requirement doubles and handling becomes unwieldy
Solution Approach 1:
The patent applies dynamics by making the rectifier configuration changeable through transistor polarity switching. Instead of using a fixed four-thyristor rectifier, the system dynamically switches between different rectifier configurations (single-phase full-wave, three-phase bridge, six-pulse) based on welding requirements, thereby avoiding magnetization only when necessary while maintaining a compact structure.
Solution Approach 2:
The patent changes the electrical parameters of the rectifier system by switching transistor polarities to alter the rectifier configuration. This allows the system to transition between different rectification modes (full-wave, bridge, six-pulse) and adjust the welding current characteristics, thereby controlling magnetization effects without requiring a permanently large four-thyristor rectifier structure.
2Object-affected harmful factors
If a rectifier having four thyristors is used to avoid magnetization effects, then magnetization is avoided, but operating properties deteriorate with higher losses and lower power
Solution Approach 1:
The system dynamically selects the appropriate rectifier configuration based on welding requirements. Instead of always operating with the less efficient four-thyristor setup, the system switches to more efficient configurations (such as three-phase bridge or six-pulse rectifiers) when magnetization avoidance is not required, thereby reducing operating losses and improving power efficiency.
Solution Approach 2:
The patent changes the operational parameters of the rectifier by switching transistor polarities to optimize efficiency. The system can transition between different rectification modes to minimize energy losses, using the four-thyristor configuration only when magnetization control is necessary and employing more efficient configurations otherwise.
3Adaptability or versatility
If polarity switching is implemented via an additional electrical cable between transformer and controller, then polarity switching is achieved, but cable defects and connection failures risk increases
Solution Approach 1:
The patent extracts the polarity switching function from the external cable connection and relocates it to the transformer's integrated control circuitry. The switching transistors and control logic are incorporated directly into the transformer assembly, eliminating the need for external cables to carry switching signals and thereby removing the associated reliability risks.
Solution Approach 2:
The patent merges the polarity switching function with the transformer by integrating the switching transistors and control circuitry directly into the transformer assembly. This combination eliminates separate cable connections for polarity control and reduces the system to fewer independent components, thereby improving reliability.
4Adaptability or versatility
If polarity switching via additional cable is implemented, then polarity switching is achieved, but space requirement for terminals and cabling outlay increases
Solution Approach 1:
The patent extracts the polarity switching function from external cabling and relocates it to the transformer's internal circuitry. This eliminates the need for additional cables and external terminals, thereby reducing the space required for cable routing and terminal installations.
Solution Approach 2:
The patent merges the polarity switching function with the transformer by integrating switching transistors and control circuitry directly into the transformer assembly. This consolidation eliminates separate cable connections and reduces the overall space requirement for terminals and cabling infrastructure.
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
The solution effectively avoids magnetization, reduces electrode erosion, and maintains high safety and efficiency, with lower losses and smaller structural size compared to existing solutions, while enabling implementable and checkable polarity switching.
Implementation Method 1
at least one welding transformer for feeding an electric current to the welding tool during the welding of the at least one component
Implementation Method 2
the polarity of one transistor of the series circuit is rotated relative to the polarity of the other transistor of the series circuit, such that the polarity of the at least one welding transformer is switchable in order to realize a polarity-switchable welding voltage and a polarity-switchable welding current
Implementation Method 3
resistance welding of at least one component with which the problems mentioned above can be solved
Implementation Method 4
as a result of different alloys for the welded metal sheets, different sheet metal thickness combinations and the Peltier effect in the case of aluminum, in a manner dependent on the welding current direction, undesired erosion at the welding electrodes and/or material creep can occur
Data Source
AI summary
A resistance welding apparatus includes a welding tool with a welding electrode configured to contact a component. A welding transformer is configured to feed an electric current to the welding tool and a control device is configured to control a polarity of welding transformer by transmitting polarity information to the welding transformer such that a polarity of the welding transformer is switchable. A circuit including two transistors is operably connected in series between the welding tool and an output of the welding transformer and a polarity one of the transistors is rotated relative to the other transistor, such that a polarity of a welding voltage at the welding electrode is switchable with the switching of the polarity of the welding transformer, and such that a polarity of a welding current at the welding transformer is switchable with the switching of the polarity of the welding transformer.