Heavy-Current Transformer Multi-Point Contacting for Energy Loss Reduction
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Solution Overview
Problem
Resistance welding devices experience high energy losses due to heavy-current transformers and power lines, leading to inefficient energy use and increased manufacturing, commissioning, and operational expenses, with existing systems achieving only about 10% efficiency when producing a spot weld with a welding current of 20 kA.
Innovation Solution
A heavy-current transformer design with multiple contacts for multi-point contacting, series/parallel connections of primary and secondary windings, and an I-beam structure that eliminates the need for connection lines, reducing ohmic and contact losses, and allowing for higher switching frequencies, thereby reducing the overall size and weight of the transformer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional separate design of heavy-current transformer and rectification is used, then device complexity is reduced, but energy losses increase significantly
Solution Approach 1:
The patent combines the heavy-current transformer with the rectification circuit into a single integrated unit. The transformer core directly houses the rectifier components, eliminating the need for separate transformer and rectifier assemblies. This merging reduces energy losses by minimizing connection points and contact resistances while consolidating device complexity into a unified structure.
Solution Approach 2:
The patent introduces an intermediate integrated structure that serves as both the transformer core and the rectifier mounting platform. This intermediary structure provides direct electrical connections between the transformer windings and rectifier elements, reducing the number of external connection points and minimizing energy losses at interfaces.
2Loss of energy
If heavy-current transformer with traditional contacting is used, then manufacturing is simplified, but contact losses increase
Solution Approach 1:
The patent extracts the contacting function from the traditional separate connection system and integrates it directly into the transformer structure. The rectifier components are mounted directly on the transformer core with minimal intermediate connections, removing the need for extensive external wiring and reducing contact losses at multiple connection points.
Solution Approach 2:
The patent segments the transformer into functional zones where each section is optimized for its specific purpose. The core structure is divided into regions for windings, rectifier mounting, and cooling, allowing each segment to be manufactured and assembled with minimal contact interfaces, thereby reducing contact losses while maintaining manufacturing simplicity.
3Productivity
If active rectifiers with control elements are used, then rectification efficiency is improved, but overall efficiency decreases due to heavy current losses
Solution Approach 1:
The patent merges the active rectifier control elements directly into the transformer structure, placing transistors and control circuits in immediate proximity to the windings. This integration minimizes the current path length and reduces ohmic losses in the heavy current paths, allowing the rectifier to operate efficiently without the penalty of long connection lines and multiple contact points.
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 reduces energy losses, increasing efficiency to approximately 20% or more, with a connected wattage for generating 20 kA reduced from 150 kW to 75 kW, and enabling the transformer to be positioned closer to the welding electrodes, reducing the load on welding robots.
Implementation Method 1
at least one primary winding (13) and at least ten secondary windings (14) with center tapping (14'), which are connected in parallel
Implementation Method 2
The outer surfaces of the I-beam (25) form the two first contacts (20, 21) of the power source (10), which are connected to corresponding components directly, i.e., without lines
Data Source
AI summary
The invention relates to a heavy-current transformer (12), in particular for a power source (10) in order to provide a welding current of a resistance welding device (1), with at least one primary winding (13) and at least one secondary winding (14) with center tapping, and to a transformer element, a contact plate (29) and a secondary winding (14) for such a heavy-current transformer (12) as well as a method for the manufacturing thereof. For reduction of losses and improvement of efficiency, at least four contacts (20, 21, 22, 23) are provided to form a multi-point contacting, said contacts (20, 21, 22, 23) being formed by four contact faces within which the at least one primary winding (13) and the at least one secondary winding (14) are arranged in a series/parallel connection.