Forward Converter Magnetic Component Bobbin-less Design

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Solution Overview

Problem

Existing forward converters with integrated magnetic components face challenges in power density, efficiency, and thermal resistance due to the use of E/ER cores with winding bobbins and single air gaps, leading to increased costs and leakage losses.

Innovation Solution

A forward converter design utilizing 8-shaped cores with magnetically coupled ring-shaped sections, where transformer windings are arranged on one section and filter output inductor windings on a bobbin-less section, allowing for bobbin-less winding and distributed air gaps to reduce leakage and thermal resistance, and using U/UR or E/ER cores with body sections for direct winding, enhancing assembly flexibility and reducing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If winding bobbins are used to arrange windings on E/ER cores, then the assembly is easier, but leakage losses and costs increase

Engineering Contradiction:
Improveease of assemblyVSAvoidleakage losses
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent removes the winding bobbins from the magnetic component assembly. The windings are arranged directly on the legs of the E/ER core without intermediate bobbins, eliminating the bobbin-related leakage losses while maintaining assembly feasibility through direct winding placement on the core legs.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the winding arrangement directly with the core structure by placing windings on the core legs themselves rather than on separate bobbins. This integration eliminates the interface between bobbin and core that causes leakage, combining the magnetic path and winding support into a unified structure.

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If a single air gap is manufactured on the centre leg of E/ER core, then the assembly is simpler, but inductance losses and flexibility increase

Engineering Contradiction:
Improveassembly simplicityVSAvoidinductance losses
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent divides the single air gap into multiple distributed air gaps across different legs of the E/ER core. Instead of one large air gap on the centre leg, multiple smaller air gaps are distributed on various legs, reducing the fringing effect and improving magnetic field distribution to lower inductance losses while maintaining assembly simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies air gaps locally on specific legs where needed rather than using a single centralized air gap. This localized distribution optimizes the magnetic properties in different regions of the core, reducing overall inductance losses while keeping the assembly process simple through standardized local modifications.

Inventive Principle:
Principle #3Local quality

3Stability of the object's composition

If legs are disposed opposed to each other in E/ER core, then the structure is more stable, but assembly becomes more complicated

Engineering Contradiction:
Improvestructural stabilityVSAvoidassembly complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent designs the E/ER core with standardized legs that can serve multiple functions - providing structural support, carrying windings, and forming magnetic paths. The legs are configured to be universally applicable for different winding arrangements and air gap positions, maintaining structural stability while simplifying assembly through standardized interfaces.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Power

If all transformer and inductor windings are wound on a single core, then power density increases, but manufacturing precision requirements increase

Engineering Contradiction:
Improvepower densityVSAvoidwinding precision
Core Design Contradiction:
PowerVSManufacturing precision

Solution Approach 1:

The patent segments the integrated magnetic component into distinct functional sections on different legs of the E/ER core. Transformer windings are placed on specific legs while inductor windings are placed on other legs, allowing separate optimization of each winding set while maintaining the integrated single-core structure. This segmentation reduces the complexity and precision requirements compared to winding all components on a single leg.

Inventive Principle:
Principle #1Segmentation

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 design achieves lower leakage and inductance losses, increased power density, reduced thermal resistance, and simplified assembly, while minimizing costs and AC winding power losses, thereby improving the efficiency and flexibility of the converter.

Implementation Method 1

an 8-shaped core with exactly two magnetically coupled ring-shaped sections, namely a first ring-shaped section and a second, at least partially bobbin-less ring-shaped section

Methodology Applied
Scientific EffectMagnetic coupling: Electromagnetic Induction

Data Source

PatentEP2624260B1Forward converter with magnetic component
Publication Date: 2018.04.04 DET INT HLDG LTD
  • EP2624260B1 patent drawingFigure 1a~1c
  • EP2624260B1 patent drawingFigure 2a~2c
  • EP2624260B1 patent drawingFigure 3a~3d

AI summary

The invention relates to a forward converter comprising a magnetic component with a transformer (P, P1, P2, S) and a filter output inductor (Ls), and to method steps in the assembly of a forward converter comprising a magnetic component with a transformer (P, P1, P2, S) and a filter output inductor (Ls). A first and a second U/UR core (U11, U12) are arranged to form an O-core, wherein windings of the transformer (P, P1, P2, S) are arranged on the O-core, wherein a bobbin-less U/UR core (U21) is arranged to abut the O-core, and wherein windings of the filter output inductor (Ls) are arranged directly on a body section of the bobbin-less U/UR core (U21). Alternatively, windings of the transformer (P, P1, P2, S) are arranged on a first section of an E/ER core (E, E1, E2), wherein windings of the filter output inductor (Ls) are arranged directly on a second, bobbin-less section of the E/ER core (E, E1, E2).