Integrated Magnetic Component for Interleaved LLC Converters

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Solution Overview

Problem

Existing power converters with interleaved LLC converters face challenges of bulky size, high core size, and increased copper losses due to strong coupling between components, which complicates engineering and reduces power density while potentially impacting EMI quality.

Innovation Solution

An integrated magnetic component design with a return leg arranged between winding carrying legs in an interleaved LLC converter configuration, allowing magnetic fluxes to share a return path and reduce total flux, thereby minimizing iron losses and stray inductances, and simplifying the design by decoupling LLC converters magnetically, reducing core size and copper losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple discrete magnetic components are used for interleaved LLC converters, then the converters can operate in parallel to increase output power and spread power losses, but the number of magnetic components doubles resulting in larger size and higher costs

Engineering Contradiction:
Improveoutput powerVSAvoidsize of magnetic components
Core Design Contradiction:
PowerVSVolume of stationary object

Solution Approach 1:

The patent merges multiple discrete magnetic components (transformers and inductors) from multiple interleaved LLC converters into a single integrated magnetic component. This integration shares common magnetic paths and cores among the converters, reducing the total number of separate components while maintaining the parallel operation capability for increased output power and distributed power losses.

Inventive Principle:
Principle #5Merging (Combining)

2Power

If multiple discrete magnetic components are used for interleaved LLC converters, then the converters can operate in parallel, but the number of windings and interconnections increases negatively impacting efficiency

Engineering Contradiction:
Improveoutput powerVSAvoidcopper losses
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent combines multiple windings from different converters onto shared magnetic cores, reducing the total number of interconnections required. This integration minimizes copper losses by eliminating redundant winding sections and reducing the length of interconnecting conductors while preserving the ability to operate multiple converters in parallel for higher output power.

Inventive Principle:
Principle #5Merging (Combining)

3Loss of energy

If magnetic components are integrated into a single structure, then power density and efficiency increase, but the design complexity and coupling between components increases

Engineering Contradiction:
Improvecore lossesVSAvoiddesign complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent segments the integrated magnetic component into distinct magnetic paths and cores that can be independently designed and analyzed. This segmentation allows for systematic design approaches, where each converter's magnetic requirements can be addressed separately while sharing common structures, thereby reducing overall design complexity despite the integration benefits for core losses and power density.

Inventive Principle:
Principle #1Segmentation

4Quantity of substance

If magnetic fluxes are strongly coupled in integrated structures, then power density increases, but EMI quality may be compromised

Engineering Contradiction:
Improvepower densityVSAvoidEMI emissions
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent implements local quality variations in the integrated magnetic structure by providing different magnetic path characteristics, air gaps, and shielding arrangements in different regions. This allows optimized magnetic coupling in areas where power density is prioritized while incorporating EMI mitigation features such as magnetic shields or spaced-apart windings in areas where electromagnetic interference control is critical, thus balancing both requirements within the same integrated structure.

Inventive Principle:
Principle #3Local quality

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 reduces core size, copper losses, and stray inductances, enhancing power density and transient characteristics without compromising EMI quality, leading to a more compact and efficient power converter design.

Implementation Method 1

magnetic fluxes generated by the windings of said two winding carrying legs, will share the return leg as return path and thus superpose each other

Methodology Applied
Scientific EffectMagnetic flux: Magnetic Field

Implementation Method 2

each leg being magnetically connected to both yokes

Methodology Applied
Scientific EffectMagnetic coupling: Electromagnetic Induction

Implementation Method 3

the winding carrying legs include a transformer air gap

Methodology Applied
Scientific EffectAir gap: Magnetic Reluctance

Data Source

PatentEP3401935B1Integrated magnetic component and power converter
Publication Date: 2020.12.02 DELTA ELECTRONICS (THAILAND) PUBLIC CO LTD
  • EP3401935B1 patent drawingFigure 1~2
  • EP3401935B1 patent drawingFigure 3~4
  • EP3401935B1 patent drawingFigure 5a~5b

AI summary

The invention relates to an integrated magnetic component (802) for a power converter including N >= 2 LLC converters configured for interleaved operation. The integrated magnetic component (802) includes a first yoke and a second yoke and for each LLC converter a winding carrying leg which comprises a primary winding (820c) and a secondary winding (821 c), wherein the primary winding (820c) and the secondary winding (821c) are wound on the respective winding carrying leg. The integrated magnetic component (802) further includes one or more return legs. Herein the winding carrying legs and the one or more return legs are arranged side by side, each leg being magnetically connected to both yokes and the winding carrying legs include a transformer air gap (819) whereas the at least one return leg is air gap free and at least one return leg is arranged between two winding carrying legs. The invention further relates to a power converter including a switching converter stage (811a, 811b, 811c), a rectifier stage (813a, 813b, 813c) and a resonant stage, the resonant stage including N >=2 parallel LLC converters.