Coaxial Cable and PCB Transformer Layout for Tight Magnetic Coupling
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Solution Overview
Problem
Conventional transformers exhibit high leakage inductance and limited turn ratios due to gaps between discrete insulated wires, limiting their coupling coefficient and efficiency.
Innovation Solution
A transformer design using coaxial cables and printed circuit board (PCB) technology, where primary and secondary windings are formed by coaxial cable portions and PCB traces, with the secondary winding turns circumferentially surrounding the primary, enhancing magnetic coupling and allowing flexible turn ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional discrete insulated wires are used for windings, then the transformer structure is simple to manufacture, but leakage inductance is high and coupling coefficient is limited
Solution Approach 1:
The patent combines discrete insulated wires into a single coaxial cable structure where the inner conductor and outer shield are tightly coupled. This merging eliminates gaps between individual wire turns, achieving superior magnetic coupling (coupling coefficient > 0.990) while maintaining manufacturing simplicity through the use of standard coaxial cable components.
Solution Approach 2:
The patent employs a nested configuration where the primary winding (inner conductor) is surrounded by the secondary winding (outer shield) of the coaxial cable. This nested arrangement maximizes magnetic flux linkage between windings, minimizing leakage inductance and enhancing coupling efficiency while maintaining a compact structure.
2Adaptability or versatility
If conventional wire windings are used, then manufacturing process is straightforward, but turn ratio flexibility is limited
Solution Approach 1:
The patent achieves turn ratio flexibility by changing the physical dimensions of the coaxial cable segments used for windings. By varying the length of the inner conductor and outer shield portions, different effective turn ratios can be obtained without changing the fundamental winding structure, allowing easy adaptation to different application requirements while maintaining straightforward manufacturing processes.
3Productivity
If gaps between discrete wires are present, then winding assembly is simple, but energy transfer efficiency is reduced
Solution Approach 1:
The patent merges multiple discrete wire turns into a continuous coaxial cable structure, eliminating gaps between individual wire segments. This continuous structure ensures uninterrupted magnetic flux paths, maximizing energy transfer efficiency through superior coupling while the coaxial cable itself remains a simple, off-the-shelf component that does not increase overall device complexity.
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 design achieves improved coupling coefficients greater than 0.990 and flexible turn ratios, reducing leakage inductance and enhancing energy transfer efficiency.
Implementation Method 1
A magnetic field generated by current flow in the primary winding inductively couples to the secondary winding, and variations in the magnetic field induce a current flow in the secondary winding
Implementation Method 2
The ferromagnetic core provides a low reluctance path for the magnetic field
Data Source
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AI summary
A transformer (200), (300), (400) and method (600) of forming is disclosed. A set of windings (201), (202) including a coaxial cable portion (251a), (252a) and a printed circuit board (PCB) trace portion (251b), (252b) are wound around a magnetic core (220). The coaxial cable portion (251a), (252a) defines a portion of the primary windings (203a), (203b), (203c) and a portion of the secondary windings (203a), (203b), (203c). The PCB trace portion (251b), (252b) includes a set of first PCB traces (211) and a set of second PCB traces (212) to define another portion of the primary winding turns (203a), (203b), (203c), and a set of third PCB traces (213) and fourth PCB traces (214) define another portion of the secondary winding turns (203a), (203b), (203c). The set of third PCB traces (213) and fourth PCB traces (214) are electrically coupled by a set of conductive vias (217). The third PCB traces (213), fourth PCB traces (214) and the set of conductive (217) vias circumferentially surround at least a portion of the first PCB trace (211) and a second PCB trace (212).