Composite Conductor Structure for Transformer Copper Loss Reduction
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Solution Overview
Problem
In switching power supply transformers, high copper loss occurs due to skin depth and proximity effects in copper sheets or single-core wires, and multi-strand wires have lower copper filling rates, leading to increased DC loss and manufacturing costs from post-processing requirements.
Innovation Solution
A composite conductive structure comprising adjacent enameled wires surrounded by a copper foil that completely covers the outside, increasing copper filling rate and reducing AC and DC losses, while simplifying post-processing and reducing manufacturing costs by shaping the enameled wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If copper sheet or single-core thick wire is used to wrap around iron core, then copper filling rate is increased, but AC loss increases due to skin depth and proximity effects
Solution Approach 1:
The conductive structure is segmented into multiple enameled wires arranged in parallel, each carrying a portion of the current. This segmentation reduces the effective cross-sectional area exposed to alternating magnetic fields, thereby suppressing AC loss from skin depth and proximity effects while maintaining high copper filling rate through tight arrangement of segments.
2Loss of energy
If multi-strand wire is used to suppress AC loss, then AC loss is reduced, but copper filling rate decreases and DC loss increases
Solution Approach 1:
The enameled wires are arranged with different local characteristics: some regions have tighter packing for high copper filling rate, while the overall bundle configuration optimizes AC loss suppression. The copper foil wrapping provides localized reinforcement and shaping without significantly increasing volume, creating optimal local quality in different regions of the conductor.
3Loss of energy
If number of strands is increased to enlarge cross-sectional area, then DC loss is reduced, but volume of multi-strand wire increases
Solution Approach 1:
Multiple enameled wires are nested tightly together in a compact arrangement, with copper foil wrapping nested around the entire bundle. This nesting configuration maximizes the copper filling rate by eliminating air gaps between strands, thereby reducing DC loss without increasing the overall volume of the conductor.
4Reliability
If tin is used to cover two ends of multi-strand wire, then conductivity is improved, but post-processing shaping treatments are required increasing manufacturing cost
Solution Approach 1:
The copper foil wrapping is applied preliminarily around the enameled wires before tinning the ends. This preliminary action provides structural support and shaping to the conductor bundle, making subsequent end-shaping operations easier and reducing the need for complex post-processing treatments, thereby lowering manufacturing cost while maintaining good conductivity.
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 composite conductive structure effectively suppresses AC loss and reduces DC loss under high wattage applications, saving volume and manufacturing costs by eliminating the need for complex post-processing treatments.
Implementation Method 1
the skin depth and proximity effect cause AC loss on the copper sheet or the single-core thick wire
Implementation Method 2
the skin depth and proximity effect cause AC loss on the copper sheet or the single-core thick wire
Implementation Method 3
a copper filling rate in the transformer must be increased to reduce a copper loss under the application of high output current
Data Source
AI summary
A composite conductive structure includes plural enameled wires and a copper foil. The enameled wires are immediately adjacent to each other and extend in the same direction. The copper foil surrounds the outside of the enameled wires at least once, and completely covers the entire outside of the enameled wires.