Coreless Transformer Galvanic Isolation Railway Sensor

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Solution Overview

Problem

Conventional transformers used for high-voltage applications, such as in the railway field, face challenges in achieving high galvanic isolation while being cost-effective, compact, and reliable due to their bulkiness and weight, which are exacerbated by vibrations and temperature variations.

Innovation Solution

A coreless transformer design utilizing two superimposed conductive coils on a printed circuit board with an insulating element in between, providing galvanic isolation without a magnetic core, and using a simplified primary circuit with low-power components to enhance energy transfer efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a classic transformer with a magnetic core is used, then galvanic isolation between primary and secondary circuits is achieved, but the device has large bulk, significant weight, and high cost

Engineering Contradiction:
Improvegalvanic isolationVSAvoidtransformer weight
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The invention extracts and removes the magnetic core from the transformer structure, retaining only the essential coils for electromagnetic induction. This extraction eliminates the heavy magnetic core while preserving the galvanic isolation function through air-core or ferrite-coreless design, directly resolving the contradiction between isolation performance and weight.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the physical parameters of the transformer by using high-frequency operation and optimized coil geometries (such as toroidal or planar coils) to achieve efficient energy transfer without a magnetic core. This parameter change allows the transformer to maintain functionality with dramatically reduced weight and size.

Inventive Principle:
Principle #35Parameter changes

2Power

If a classic transformer with a magnetic core is used, then energy transfer between circuits is achieved, but the device has large bulk and volume

Engineering Contradiction:
Improveenergy transfer capabilityVSAvoidtransformer volume
Core Design Contradiction:
PowerVSVolume of stationary object

Solution Approach 1:

By removing the bulky magnetic core, the transformer volume is dramatically reduced while maintaining energy transfer capability through optimized coil designs that rely on electromagnetic induction in air or minimal ferrite materials, directly addressing the volume-power contradiction.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention transitions from traditional three-dimensional magnetic core structures to planar or toroidal coil configurations that utilize two-dimensional space more efficiently, reducing the overall volume occupied by the transformer while maintaining its power transfer function.

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

3Reliability

If a classic transformer with a magnetic core is used, then galvanic isolation is provided, but the manufacturing cost is high

Engineering Contradiction:
Improvegalvanic isolationVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Removing the magnetic core eliminates the need for complex core manufacturing processes, precision stacking, and magnetic material handling, thereby significantly reducing manufacturing costs while maintaining galvanic isolation through simpler coil-based designs that are easier to produce.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention employs simpler, cheaper materials and construction methods for the transformer coils that can be manufactured using standard PCB or wire-winding techniques, replacing expensive magnetic core assemblies with more economical air-core or minimal-core designs that achieve the same isolation function at lower cost.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Power

If a classic transformer with a magnetic core is used, then energy transfer is achieved, but the device is susceptible to wear and rupture under vibrations and temperature variations

Engineering Contradiction:
Improveenergy transferVSAvoidresistance to vibrations and temperature variations
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

By extracting the magnetic core, the invention eliminates the mechanical connections and welds required to attach heavy core components, which are vulnerable to vibration-induced fatigue and thermal expansion. The coreless design with suspended or mounted coils reduces mechanical stress points, directly improving reliability under harsh environmental conditions while maintaining energy transfer capability.

Inventive Principle:
Principle #2Taking out (Extraction)

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 significant galvanic isolation, reduces size and cost, and increases reliability by eliminating the need for additional components and welds, making it suitable for high-voltage applications like railways and other on-board solutions.

Implementation Method 1

A first object of the invention consists in proposing an electronic apparatus which offers high galvanic isolation between a primary circuit and a secondary circuit

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2348516B2Railway sensor including a coreless transformer with high galvanic insulation
Publication Date: 2023.07.26 RWAYTECH
  • EP2348516B2 patent drawingFigure 1~2
  • EP2348516B2 patent drawingFigure 3~4b
  • EP2348516B2 patent drawingFigure 5~7

AI summary

The transformer (10) has a printed circuit type insulating element (13) and conductive coils (11, 12) positioned in a superposed manner on opposite faces of the insulating element. The conductive coils are is circular, elliptical, square or rectangular shapes. The coils are in a form of flexible or rigid plastic plate. Each coil includes flat metallic winding turns provided with central ends. Electric wires are positioned at a surface of the insulating element. The coils are separated by the insulating element. An independent claim is also included for an electrical apparatus comprising a printed circuit on which electrical components are arranged.