Nested Flat-Wound Transformer Windings for Variable Thickness

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Solution Overview

Problem

Current transformer designs have limited conductor fill factor, fixed winding thickness, and lack design flexibility, making it difficult to create high-power transformers with variable thickness and coil arrangements in reduced-sized packages.

Innovation Solution

The use of nested flat wound coils with inner and outer windings wound on different mandrels, allowing for variable thickness and multiple coil arrangements, enabling higher turn counts and higher power transformers in a lower profile package.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If printed circuit boards are used for windings, then manufacturing is simplified, but conductor fill factor is limited to approximately 35%

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidconductor fill factor
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

The winding structure is segmented into multiple independent flat wound coils that can be nested within each other. Each coil is wound separately on its own mandrel, allowing independent optimization of each winding layer. This segmentation enables the coils to be stacked vertically to achieve higher conductor fill factors while maintaining manufacturing simplicity through standardized coil production processes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple flat wound coils are nested within each other in a vertical stacking arrangement, with smaller diameter coils positioned inside larger diameter coils. This nesting configuration maximizes the use of available magnetic core window space, increasing the conductor fill factor from 35% to over 60% while maintaining a compact transformer structure.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Device complexity

If traditional windings are used, then structure is simple, but design flexibility for variable thickness and coil arrangements is limited

Engineering Contradiction:
Improvestructural simplicityVSAvoiddesign flexibility
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The transformer design employs dynamic coil configurations where the number, thickness, and arrangement of flat wound coils can be varied to meet different power and electrical specification requirements. Designers can select from multiple coil combinations and nesting arrangements to optimize performance for specific applications, providing adaptability while maintaining relatively simple individual coil structures.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Different regions of the transformer winding structure can have different coil specifications, including varying wire thicknesses, turn counts, and nesting arrangements tailored to local electrical requirements. This allows optimization of specific winding sections for different electrical stresses and performance criteria while keeping other sections simpler.

Inventive Principle:
Principle #3Local quality

3Power

If higher power transformers are designed, then power capacity increases, but transformer height increases

Engineering Contradiction:
Improvepower capacityVSAvoidtransformer height
Core Design Contradiction:
PowerVSLength of stationary object

Solution Approach 1:

The design transitions from horizontal winding expansion to vertical stacking of nested coils, utilizing the vertical dimension more efficiently. By nesting coils vertically and stacking them along the magnetic core window height, the design achieves higher power capacity without proportionally increasing transformer footprint, effectively redistributing dimensions to optimize power density.

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

Solution Approach 2:

Multiple coils are nested within each other vertically, with each nested coil contributing to the overall power capacity. This nesting arrangement allows higher power transformers to be achieved by increasing the number of nested coil layers rather than increasing individual coil sizes, thereby controlling the overall transformer height while increasing power capacity.

Inventive Principle:
Principle #7Nested doll (Nesting)

4Loss of energy

If fewer turns are used, then winding resistance decreases, but leakage inductance increases

Engineering Contradiction:
Improvewinding resistanceVSAvoidleakage inductance
Core Design Contradiction:
Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The total number of turns is segmented across multiple nested coils rather than concentrated in a single winding. This segmentation allows the magnetic flux to be more uniformly distributed across multiple parallel paths, reducing leakage inductance while maintaining lower overall winding resistance through optimized turn distribution and parallel winding configurations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple nested coils are electrically connected in parallel or series-parallel configurations, merging their individual contributions to achieve both low winding resistance and controlled leakage inductance. The combined effect of multiple nested windings creates more efficient magnetic coupling and reduces harmful leakage inductance while distributing the total turn count to minimize resistive losses.

Inventive Principle:
Principle #5Merging (Combining)

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 achieves higher turn counts, increased power capacity, and improved copper density, allowing for higher current capability and reduced leakage inductance, while enabling more efficient use of magnetic core space.

Implementation Method 1

a varying current in the transformer's primary winding creates a varying magnetic flux in the transformer core and a varying magnetic field impinging on the transformer's secondary winding. This varying magnetic field at the secondary winding induces a varying EMF or voltage in the secondary winding due to electromagnetic induction

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

Transformers rely on Faraday's Law and high magnetic permeability core properties, to efficiently change AC voltages from one voltage level to another

Methodology Applied
Scientific EffectMagnetic permeability: Ferromagnetism

Data Source

PatentEP3453036B1Nested flat wound coils forming windings for transformers and inductors
Publication Date: 2023.11.08 VISHAY DALE ELECTRONICS INC
  • EP3453036B1 patent drawingFigure 1
  • EP3453036B1 patent drawingFigure 2
  • EP3453036B1 patent drawingFigure 3

AI summary

An electro-magnetic device is provided, including a first winding set of nested windings, and a second winding set of nested windings positioned adjacent to the first winding set. A method of making an electro-magnetic device including a first winding set of nested windings, and a second winding set of nested windings positioned adjacent to the first winding set is also provided.