Magnetic Structures for Low Leakage Inductance and High Efficiency
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Solution Overview
Problem
Current magnetic structures for power converters and inductors face challenges in reducing leakage inductance and stray inductance, particularly at high frequencies, which limits their ability to minimize footprint and power dissipation, especially when using thin copper and multilayer PCBs.
Innovation Solution
The magnetic structures employ a configuration with multiple magnetic flux conducting posts and plates, optimized winding arrangements, and the integration of rectifier means within the windings to enhance copper utilization and reduce leakage inductance, featuring a center tap topology and four-legged magnetic core configurations that allow for efficient current flow and reduced magnetic core volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple independent transformers with series primary windings are employed to handle high currents, then the current processing capability is improved, but the leakage inductance and stray inductance increase
Solution Approach 1:
The patent merges multiple magnetic cores into a single integrated structure with shared magnetic flux paths. The primary and secondary windings are coupled across multiple cores in a way that creates common magnetic paths, reducing the total leakage inductance while maintaining high current processing capability through the combined structure.
2Loss of energy
If the length of magnetic winding is reduced to lower power dissipation in thin copper, then copper power dissipation is improved, but the magnetic coupling and inductance control become more difficult
Solution Approach 1:
The patent implements different winding configurations for different sections of the magnetic structure. Primary windings and secondary windings are arranged with optimized local coupling characteristics, allowing short winding lengths to achieve effective magnetic coupling through strategically placed high-permeability magnetic paths and localized flux confinement.
3Area of stationary object
If magnetic core volume is reduced for smaller footprint, then the footprint is improved, but the magnetic flux conduction and inductance stability deteriorate
Solution Approach 1:
The patent employs a nested magnetic core configuration where multiple magnetic paths are integrated within a compact footprint. The magnetic cores are arranged to share flux paths and provide mutual support, maintaining inductance stability through the nested structure while minimizing the overall footprint area.
4Productivity
If higher operating frequency is employed to reduce component size, then the power conversion efficiency is improved, but the high frequency losses such as proximity losses and skin effect losses increase
Solution Approach 1:
The patent transitions from planar winding arrangements to three-dimensional magnetic structures with vertical flux paths. This dimensional change allows for shorter current paths and reduced winding lengths, thereby reducing skin effect and proximity losses at high frequencies while maintaining effective magnetic coupling through the vertical magnetic core structure.
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 significantly reduces leakage inductance, improves copper utilization, and minimizes power dissipation, making it suitable for high-frequency applications with a smaller footprint and lower core losses, while allowing for efficient power conversion and inductive operations.
Implementation Method 1
a plurality in excess of two magnetic flux conducting posts penetrating through the circuit board, at least two magnetic flux conducting plates connecting on both sides of the magnetic flux conductive posts
Implementation Method 2
at least two connected primary winding encircling the magnetic posts, and at least two connected secondary winding encircling the magnetic posts
Data Source
AI summary
A magnetic configuration utilizing a plurality of posts and spiting the primary winding on each of the posts defining a core and placing the secondary windings together with the rectifier means around each post to minimise the stray and leakage inductance. A significant reduction of the core material and a reduction of the footprint is achieved due to better utilization of the winding material. The magnetic field is weaving from and through one post to the other to minimize the vertical component of ther field and forcing the magnetic field to be parallel with the winding to reduce the AC losses in copper of the winding. These properties allow the magnetic structure to be suitable in very high frequency applications and even in application with an air core. These magnetic structures can be used for implementing a transformer and for inductive applications.