Concentric Winding Transformer for Electric Vehicle

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Solution Overview

Problem

Existing transformers for electrically driven vehicles face inefficiencies in energy transfer and increased energy losses due to magnetic leakage flux, particularly in the conversion of high voltage to traction and auxiliary voltages, leading to higher manufacturing costs and thermal loads.

Innovation Solution

A transformer design with a traction secondary winding arranged concentrically around a magnetically conductive core, a high-voltage primary winding in an outer layer, and an auxiliary secondary winding with two coils encasing the primary winding, optimizing inductive coupling and reducing magnetic leakage flux, thereby enhancing energy transfer efficiency and reducing losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional winding arrangements (disc or tubular) are used, then the transformer structure is simpler, but energy transfer efficiency is reduced due to magnetic leakage flux

Engineering Contradiction:
Improveenergy lossesVSAvoidwinding arrangement complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent applies nesting by arranging the high-voltage primary winding, traction secondary winding, and auxiliary secondary winding in concentric layers around the core. The traction secondary winding is placed in an inner layer, the high-voltage primary winding in a middle layer, and the auxiliary secondary winding in an outer layer, with each winding nested within the electromagnetic field of the others to maximize flux utilization and minimize leakage.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from planar disc winding arrangements to a three-dimensional concentric cylindrical arrangement. This dimensional change allows the windings to be positioned in radial layers around the core, creating overlapping magnetic flux paths that reduce leakage flux and improve coupling between windings.

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

2Temperature

If magnetic leakage flux is not optimized, then the transformer construction is simpler, but thermal load increases

Engineering Contradiction:
Improvethermal loadVSAvoidwinding arrangement complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The concentric nesting of windings ensures that magnetic flux generated by the high-voltage primary winding passes through both the traction secondary and auxiliary secondary windings in sequence. This nested arrangement minimizes flux leakage and reduces unwanted eddy currents in the tank and structural components, thereby reducing thermal load.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Use of energy by moving object

If conventional winding arrangements are used, then manufacturing costs are lower, but energy transfer efficiency is reduced

Engineering Contradiction:
Improveenergy transfer efficiencyVSAvoidmanufacturing cost
Core Design Contradiction:
Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The patent employs a three-dimensional concentric winding arrangement where windings are positioned in radial layers around the core rather than in planar discs. This dimensional reconfiguration optimizes magnetic flux linkage and reduces leakage, significantly improving energy transfer efficiency despite the increased manufacturing complexity.

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

4Use of energy by moving object

If windings are arranged to maximize coupling, then energy transfer efficiency improves, but the transformer occupies more space

Engineering Contradiction:
Improveenergy transfer efficiencyVSAvoidtransformer volume
Core Design Contradiction:
Use of energy by moving objectVSVolume of moving object

Solution Approach 1:

The concentric nesting of windings allows maximum magnetic coupling between the high-voltage primary, traction secondary, and auxiliary secondary windings within a compact cylindrical volume. Each winding is positioned in a radial layer, creating efficient flux paths that maximize energy transfer while minimizing the overall transformer dimensions.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 a high efficiency in energy transfer to the traction secondary voltage while minimizing energy losses and thermal loads, allowing for a more cost-effective and space-saving transformer construction.

Implementation Method 1

an upper voltage primary winding fed with the upper voltage is inductively coupled to a traction secondary winding and to an auxiliary operating secondary winding

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a magnetically conductive core

Methodology Applied
Scientific EffectMagnetic conduction: Magnetic Field

Data Source

PatentEP2639800B1Transformer for an electric vehicle
Publication Date: 2014.10.15 SIEMENS AG
  • EP2639800B1 patent drawingFigure 1
  • EP2639800B1 patent drawingFigure 2
  • EP2639800B1 patent drawingFigure 3

AI summary

The transformer has a traction secondary winding (2) that is arranged in an inner layer (6) concentrically around a core limb (4). A high-tension primary winding (1) and an auxiliary operation secondary winding (3) are arranged in an outer layer (7) concentrically around core limb and traction secondary winding. The auxiliary operation secondary winding is composed of two electrically connected coils (3.1,3.2) which enclose the high-tension primary winding in axial direction (A).