Coaxial Cable and PCB Transformer Windings for Low Leakage
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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, allowing for improved magnetic coupling and 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 the coupling coefficient is limited and leakage inductance is high
Solution Approach 1:
The patent combines discrete insulated wires into a single coaxial cable structure where the inner conductor and outer shield are continuously connected. This merging eliminates gaps between individual wire turns, improving magnetic coupling and reducing leakage inductance while maintaining manufacturing simplicity through standard coaxial cable assembly techniques.
Solution Approach 2:
The patent employs a nested configuration where the inner conductor is positioned within the outer shield of the coaxial cable, and both are wound around the magnetic core. This nested structure ensures tight coupling between primary and secondary windings, maximizing the coupling coefficient while allowing for compact manufacturing using conventional winding processes.
2Productivity
If conventional wire windings are used, then the transformer can be manufactured with standard processes, but the turn ratio is limited and energy transfer efficiency is reduced
Solution Approach 1:
The patent merges primary and secondary windings into a single coaxial cable assembly, allowing for flexible turn ratios to be achieved by simply adjusting the number of turns of the coaxial cable around the core. This approach improves energy transfer efficiency through reduced leakage inductance while avoiding complex multi-layer winding structures.
Solution Approach 2:
The patent changes the fundamental parameter of winding construction from discrete insulated wires to a continuous coaxial cable structure. This parameter change enables broader turn ratio flexibility and improved energy transfer efficiency while maintaining compatibility with standard transformer manufacturing processes.
3Reliability
If gaps between discrete wires are present, then the winding assembly is easier to construct, but leakage inductance increases and coupling is reduced
Solution Approach 1:
The patent merges multiple discrete wire turns into a continuous coaxial cable structure, eliminating gaps between individual wires. The inner conductor and outer shield maintain continuous electrical connection throughout the winding, ensuring consistent magnetic coupling and reduced leakage inductance while remaining constructible using standard cable winding methods.
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 design achieves a higher coupling coefficient and reduced leakage inductance, enabling transformers with turn ratios beyond 1:1 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
AI summary
A transformer and method of forming is disclosed. A set of windings including a coaxial cable portion and a printed circuit board (PCB) trace portion are wound around a magnetic core. The coaxial cable portion defines a portion of the primary windings and a portion of the secondary windings. The PCB trace portion includes a set of first PCB traces and a set of second PCB traces to define another portion of the primary windings, and a set of third PCB traces and fourth PCB traces define another portion of the secondary windings. The set of third PCB traces and fourth PCB traces are electrically coupled by a set of conductive vias. The third PCB traces, fourth PCB traces and the set of conductive vias circumferentially surround at least a portion of the first PCB trace and a second PCB trace.