Planar Transformer Terminal Layout for Lower High-Frequency AC Loss
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Solution Overview
Problem
Planar transformers experience significant termination losses due to current crowding and increased AC resistance caused by the proximity effect in terminals, especially at high switching frequencies and power levels.
Innovation Solution
The use of vertically oriented terminal leads with large surface area faces and a notch or groove in the windings to accept these terminals, which allows for even current distribution and balanced AC impedance, reducing termination losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If high switching frequencies are used in planar transformers, then power converter size and weight are reduced, but termination losses increase significantly
Solution Approach 1:
The patent applies local quality by making the terminal leads vertically oriented with large surface area faces specifically at the connection regions where current crowding occurs. This localized geometric modification addresses the termination loss problem at the critical interface without changing the overall transformer design, allowing high frequency operation while reducing losses at the specific problem area.
Solution Approach 2:
The patent transitions from traditional T-shaped terminal leads to vertically oriented terminal leads, changing the dimensional orientation of the connection interface. This dimensional change allows current to distribute more evenly across the vertical surface area, reducing the proximity effect and termination losses that dominate at high switching frequencies.
2Ease of manufacture
If traditional T-shaped terminal leads are used, then manufacturing is simpler, but current distribution is uneven causing high termination losses
Solution Approach 1:
The patent modifies the terminal lead geometry locally by adding vertical orientation and large surface area faces to the connection regions. This localized geometric enhancement improves current distribution and reduces termination losses without fundamentally changing the manufacturing process, maintaining ease of production while achieving lower losses.
3Reliability
If parallel windings are connected with edge-to-edge terminal orientation, then AC impedance balancing is achieved, but current crowding at edges increases losses
Solution Approach 1:
The patent changes the terminal orientation from edge-to-edge to vertical面对面 (face-to-face) configuration. This dimensional change allows current to distribute across the vertical surface area rather than concentrating at the edges, reducing proximity effect losses while maintaining AC impedance balance between parallel windings.
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 configuration reduces total losses by 55% compared to traditional T-shaped terminal leads, with lower termination losses and more even current distribution within the terminals and bus bars.
Implementation Method 1
Termination losses are caused by current concentrations at the transformer interfaces due to the proximity effect in terminals, bus bars, or circuit board traces.
Data Source
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AI summary
A planar transformer includes a magnetic core (22) having an internal opening. A plurality of high current capacity windings (34) are disposed within the internal opening. These high current capacity windings (34) have a length, a width and a thickness. Each winding is formed as an open loop having adjacent first and second end portions. There is at least one primary winding and one secondary winding. The primary winding and/or secondary winding may be high current capacity windings. A first terminal lead (30) is electrically interconnected to multiple adjacent first end portions and a second terminal lead is electrically interconnected to multiple second end portions. Both the first terminal lead (30) and said second terminal lead have a length, a width and a thickness measured with the thickness being less than either the terminal lead length or the terminal lead width.