Low Noise Transformer with Segmented Axial Coils

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Solution Overview

Problem

Conventional transformers are not suitable for applications requiring a miniaturized, elongated design with extremely low noise emissions and high efficiency, especially in the automotive sector, due to their compact, cubic shape and high noise levels, which are not met by existing transformer designs in terms of shape, dimensions, performance class, or cost.

Innovation Solution

A transformer with a housing featuring axially aligned coils mechanically chained together using symmetrical clip connections, a special transformer core with an elongated ED sheet metal yoke, and enameled wire windings, which creates a high leakage flux and significantly reduces noise emissions while maintaining low manufacturing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If conventional compact cubic transformer design is used, then manufacturing cost is reduced and magnetic flux path is shortened, but the transformer cannot achieve miniaturized elongated design with cross-sectional dimensions of a few square centimeters

Engineering Contradiction:
Improveelongated flat designVSAvoidcoil arrangement complexity
Core Design Contradiction:
ShapeVSDevice complexity

Solution Approach 1:

The transformer windings are divided into multiple axially aligned coils distributed over three chambers, with the primary coil in the central chamber and secondary coils in the lateral chambers. This segmentation allows the transformer to achieve an elongated flat design while maintaining efficient magnetic coupling through the common magnetic core.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The transformer transitions from a conventional cubic three-dimensional arrangement to an elongated flat configuration by distributing coils axially across multiple chambers along the magnetic core. This dimensional reorganization achieves the required shape with cross-sectional dimensions of a few square centimeters while maintaining electrical performance.

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

2Object-affected harmful factors

If conventional transformer design is used, then standard construction is simplified, but noise emissions are too high for automotive applications requiring extremely low structure-borne and airborne noise

Engineering Contradiction:
Improvenoise emissionsVSAvoidproduction complexity
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The transformer is divided into three separate chambers with axially aligned coils, isolating magnetic flux paths and reducing electromagnetic interference and noise emissions. This segmentation allows each coil to be optimized for minimal noise while maintaining overall transformer efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A common magnetic core serves as an intermediary that couples the primary and secondary coils axially aligned across different chambers. This intermediate magnetic path enables efficient energy transfer while physically separating the coils to reduce noise emissions to levels suitable for automotive applications.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If axially aligned coils over three chambers are used, then leakage inductance is increased and noise is reduced, but the transformer requires precise mechanical chaining with symmetrical clip connections

Engineering Contradiction:
Improvetemperature and climate resistanceVSAvoidmechanical chaining complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple axially aligned coils are mechanically chained together using symmetrical clip connections that combine the coils into a unified assembly. This merging approach ensures precise alignment and spacing critical for achieving the desired leakage inductance and noise reduction while maintaining reliability across temperature and climate variations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The symmetrical clip connections are designed with asymmetric engagement features that ensure correct orientation and positioning of each coil relative to the magnetic core. This asymmetric design within a symmetric overall structure guarantees reliable mechanical chaining that maintains precise geometric relationships essential for transformer performance.

Inventive Principle:
Principle #4Asymmetry

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 transformer achieves low structure-borne and airborne noise emissions, high output voltage, and efficient operation with a significantly lower no-load current, making it suitable for capacitive loads and cost-effective production, particularly in the automotive sector.

Implementation Method 1

An electrical transformer with a housing, the transformer windings being distributed as linearly successive, axially aligned coils over three chambers and having a single centrally symmetrically arranged primary coil and two further coils connected together as a secondary winding

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

A further aspect of the solution consists in a method for producing such a transformer with a housing according to claim 11

Methodology Applied
Scientific EffectMagnetic flux: Magnetic Field

Data Source

PatentEP3304570B1Low noise special transformer
Publication Date: 2020.09.02 MANFRED SCHMELZER
  • EP3304570B1 patent drawingFigure 1
  • EP3304570B1 patent drawingFigure 2
  • EP3304570B1 patent drawingFigure 3

AI summary

The invention relates to a temperature resistant special transformer having excellent structure borne sound and/or airborne sound behaviour at the same time as a small, extremely flat construction and excellent overall efficiency. According to the invention, the transformer windings are distributed over three chambers as linearly consecutive, aligned coils having a single centrosymmetric primary coil (20) and two further coils (10, 30), electrically interconnected as a secondary winding, the coils being mechanically linked to one another in a chain. Such a transformer has a significantly lower input current in idle than in the lowest intended capacitive loading condition. In addition, the aforementioned advantageous acoustic characteristics are further improved by means of a special encapsulation of the transformer in an associated housing. The invention also relates to a method for producing the transformer at optimal cost and to the use of such a transformer in the automotive sector.