PCB Coupled Inductors for Low-Saturation Multiphase Filtering
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Solution Overview
Problem
Conventional inductors in power converters face challenges with magnetic saturation and high losses due to DC/low-frequency and high-frequency magnetic fields, limiting the reduction of inductor size and weight, especially in interleaved structures where independent inductors increase weight and complexity.
Innovation Solution
The use of through-output coupled inductors designed using PCB-based technologies, where each inductor is wound as a solenoid on a substrate with magnetic materials, and coupled via conductive material, allowing magnetic compensation and reduced leakage inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If independent inductors are used in interleaved structures, then filtering performance is improved, but weight and device complexity increase significantly
Solution Approach 1:
The patent combines multiple independent inductors into a single integrated inductor structure where multiple windings share a common magnetic core. This merging approach maintains the filtering performance of separate inductors while significantly reducing the overall weight and volume by eliminating redundant magnetic materials and structural components.
Solution Approach 2:
The integrated inductor structure serves multiple functions simultaneously: it provides filtering for multiple phases, acts as a magnetic coupling element for differential mode noise suppression, and reduces leakage inductance for common mode filtering. This multi-functionality replaces what would traditionally require multiple separate components.
2Reliability
If independent inductors are used in interleaved structures, then filtering performance is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple inductor functions into a single integrated component with shared magnetic core and coupled windings. This consolidation reduces the number of discrete parts, simplifies assembly, and decreases overall device complexity while maintaining the filtering performance that would otherwise require multiple independent inductors.
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 effectively reduces magnetic saturation and increases filtering efficiency by decoupling LF/DC magnetic fields, enabling smaller, lighter, and more efficient inductors with reduced current ripple and loss levels.
Implementation Method 1
The coupling with the output current is performed through compensation turns done by foils made of conductive material... the two inductors are magnetically coupled through the conductive material for multiple frequencies of N·Fsw
Implementation Method 2
Conventional inductors involve a DC (Direct current) or LF (low frequency) field component superimposed to a HF (High Frequency) component. Magnetic saturation is the most critical point to address... the HF induction field BHF evolves irrespective of the magnetic permeability which is not the case of the low frequency or DC induction field BDC/LF
Data Source
AI summary
The present invention concerns a multiphase system comprising a power converter having at least two legs and a filtering device connected to the at least two legs of the power converter, the filtering device being composed of at least two inductors, each inductor being composed of turns wounded around a magnetic material. The magnetic material is disposed within at least one printed circuit board that comprises connections of the inductors and the filtering device further comprises a conductive material surrounding the at least two inductors, a first terminal of each inductor being respectively connected to one leg of the power converter and one terminal of the conductive material is connected to the second terminals of the inductors.