Foldable PCB Inductive Assembly for High-Power Integration

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Solution Overview

Problem

Existing inductive assemblies for power electronics, such as transformers and inductors supporting at least 1 kilowatt, face challenges including low copper filling, high copper losses due to DC and high-frequency effects, poor cooling, and limited integration, leading to inefficiencies and increased costs.

Innovation Solution

An inductive assembly featuring a support with an open channel and a foldable printed circuit board (PCB) that surrounds a magnetic piece, allowing for efficient electrical connection and heat dissipation, with optional additional PCBs for enhanced connectivity and cooling, enabling high-power operation with reduced size and mass.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If discrete components are used for inductors or transformers, then power handling capability is achieved, but integration level is low and manufacturing cost is high

Engineering Contradiction:
Improvepower handling capabilityVSAvoidintegration level
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent merges multiple discrete components (inductor windings, magnetic core, cooling channels, and circuit board) into a single integrated assembly. The inductive assembly combines the magnetic piece, PCB with cooling channels, and windings into one unified structure that handles kilowatt-level power while achieving high integration, eliminating the need for separate discrete components and manual assembly.

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If planar architecture is used for integrated inductors, then integration is improved, but copper filling is poor and copper losses are high

Engineering Contradiction:
Improveintegration levelVSAvoidcopper losses
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent transitions from a purely planar PCB architecture to a three-dimensional structure by folding the PCB and wrapping windings around a central magnetic piece. This dimensional change allows for significantly increased copper filling ratio and reduced copper losses while maintaining integration benefits, as the windings can now utilize the vertical space around the magnetic core rather than being constrained to a flat plane.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Device complexity

If planar architecture is used for integrated inductors, then integration is improved, but cooling performance is poor

Engineering Contradiction:
Improveintegration levelVSAvoidcooling performance
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The patent implements a nested structure where cooling channels are integrated within the PCB layers, which themselves surround the magnetic piece. The PCB is folded to create multiple cooling channels that are positioned in close proximity to the windings and magnetic piece, enabling efficient heat dissipation from the internal components while maintaining a compact integrated form factor.

Inventive Principle:
Principle #7Nested doll (Nesting)

4Device complexity

If embedded toroid architecture is used, then integration is improved, but size is limited to Watt level or less

Engineering Contradiction:
Improveintegration levelVSAvoidpower handling capability
Core Design Contradiction:
Device complexityVSPower

Solution Approach 1:

The patent employs a dynamic, foldable PCB structure that can be configured to surround the magnetic piece in multiple directions. This dynamic architecture allows the inductive assembly to scale to kilowatt-level power handling capabilities while maintaining high integration, overcoming the size limitations of fixed embedded toroid designs that are constrained to Watt-level applications.

Inventive Principle:
Principle #15Dynamics

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 solution achieves high efficiency, low losses, and easy cooling, making it suitable for kilowatt-level applications with a compact and adaptable design, reducing manufacturing costs and improving performance compared to traditional discrete component assemblies.

Implementation Method 1

The printed circuit board is arranged to surround at least partially a portion of the magnetic piece in the folded state in the channel such that at least one connecting spot of a first track is electrically connected to a connecting spot of a second track to form a winding around the magnetic piece and to inductively couple the printed circuit board and the magnetic piece

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3364429B1Inductive assembly
Publication Date: 2019.08.14 MITSUBISHI ELECTRIC R&D CENTRE EUROPE BV
  • EP3364429B1 patent drawingFigure 1
  • EP3364429B1 patent drawingFigure 2~3
  • EP3364429B1 patent drawingFigure 4

AI summary

An inductive assembly (100) comprising: - a support (1) with an open channel (12) having a straight portion with a bottom surface (13) and two side surfaces (14, 15), - a foldable PCB (2) such that to cover at least a part of the bottom surface and the side surfaces, the PCB comprising a plurality of tracks (27), each track being electrically continuous between a pair of connecting spots (28a, 28b), - a magnetic piece (3) which can be accommodated into the channel equipped with the PCB. The PCB is arranged to surround at least partially a portion of the magnetic piece in the folded state in the channel such that at least one connecting spot of a first track is electrically connected to a connecting spot of a second track to form a winding around the magnetic piece and to inductively couple the PCB and the magnetic piece.