Planar Transformer Winding Layout for Lower Common Noise
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Solution Overview
Problem
Planar transformers in low-voltage DC to DC converters for eco-friendly vehicles face issues with increased common noise and reduced efficiency due to high coupling coefficients and parasitic capacitance, which affect power density and size requirements.
Innovation Solution
A planar transformer design with optimized winding structure, including primary and secondary coil elements on a flat plate, insulated by varying thickness insulating sheets, and cores to manage capacitance and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If primary and secondary windings are replaced with PCB pattern to reduce transformer size, then the transformer volume is reduced, but the coupling coefficient between primary and secondary windings increases, causing increased parasitic capacitance and common noise
Solution Approach 1:
The transformer windings are segmented into multiple discrete coil elements arranged in a specific pattern. The primary winding is divided into multiple primary coil elements and the secondary winding into multiple secondary coil elements, which are alternately arranged. This segmentation reduces the parasitic capacitance between windings compared to a continuous PCB pattern, thereby reducing common noise while maintaining the compact planar structure.
Solution Approach 2:
The patent uses composite construction by combining multiple coil elements with specific insulation materials between layers. The insulating sheets with optimized thickness provide electrical isolation while the alternating arrangement of primary and secondary coil elements creates a composite winding structure that reduces coupling coefficient and parasitic capacitance compared to conventional PCB patterns.
2Volume of moving object
If PCB pattern is used for windings to reduce size, then the transformer dimensions are reduced, but the current-conducting area decreases, reducing system efficiency
Solution Approach 1:
The windings are segmented into multiple coil elements that can be optimally sized for current conduction. Each coil element can have sufficient copper thickness and width to handle the required current, unlike a single large PCB trace. This segmentation allows maintaining high current-conducting area while achieving compact overall dimensions through the alternating layered arrangement.
Solution Approach 2:
The patent transitions from a planar PCB pattern to a three-dimensional alternating layered structure. By stacking primary and secondary coil elements in alternating layers, the design achieves compact footprint in the planar dimensions while maintaining adequate current-conducting area through vertical stacking, effectively utilizing the third dimension to resolve the contradiction between size and efficiency.
3Volume of moving object
If coupling coefficient between primary and secondary windings is increased, then transformer size is reduced, but the resonant waveform magnitude of leakage inductance and parasitic capacitance increases, reducing system efficiency
Solution Approach 1:
The patent applies local quality optimization by carefully controlling the spacing and arrangement of individual coil elements within the transformer. The alternating arrangement of primary and secondary coil elements with appropriate insulation creates localized regions of optimized magnetic coupling, achieving compact size while managing the coupling coefficient to minimize resonant effects and maintain system efficiency.
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
Enhances efficiency and reduces common noise, improving power density and reducing size, while maintaining electromagnetic insulation and thermal performance.
Implementation Method 1
a plurality of secondary coil elements included on the flat plate and having an induced current generated by the primary coil elements
Data Source
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AI summary
Provided is a planar transformer, and more particularly, a planar transformer including: a plurality of primary coil elements included on a flat plate and laminated together; and a plurality of secondary coil elements included on the flat plate and having an induced current generated by the primary coil elements, wherein the plurality of secondary coil elements are respectively disposed above and below the primary coil element.