Coil Device Cooling Plate Eddy Current Reduction

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Solution Overview

Problem

Existing coil devices for power converters face challenges in heat dissipation due to induced eddy currents in metallic cooling plates, which result in ohmic losses and inefficient cooling, especially when using metallic heat sinks or hollow conductors.

Innovation Solution

A coil device design featuring a cooling plate thermally coupled to coil windings, with windings arranged spatially offset by an angle of 2π/N and a cooling channel extending partially around each winding, reducing eddy currents through a non-metallic coolant and improved thermal conductivity, and incorporating an electrically insulating layer to minimize electrical interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a metallic cooling plate is incorporated in the coil device to improve heat dissipation, then thermal conductivity is improved, but eddy currents are induced resulting in ohmic losses

Engineering Contradiction:

Improveheat dissipationVSAvoidohmic losses

Core Design Contradiction:

TemperatureVSLoss of energy

Solution Approach 1:

The patent introduces an electrically insulating layer between the coil windings and the cooling plate to act as an intermediary. This layer prevents direct electrical contact that would allow eddy currents to form in the metallic cooling plate, while still allowing thermal energy to be transferred from the windings to the cooling plate for effective heat dissipation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The cooling plate is segmented into multiple cooling channels that are electrically isolated from each other. This segmentation breaks up continuous electrical paths that would otherwise allow large eddy currents to flow, reducing ohmic losses while maintaining thermal conductivity through the plate structure.

Inventive Principle:

Principle #1Segmentation

2Temperature

If the cooling plate is thermally coupled to coil windings to improve heat dissipation, then thermal conductivity is improved, but electrical insulation is compromised

Engineering Contradiction:

Improveheat dissipationVSAvoidelectrical insulation

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

An electrically insulating layer is introduced as an intermediary between the conductive cooling plate and the coil windings. This layer maintains electrical insulation reliability while allowing thermal energy to pass through, thus preserving both electrical isolation and thermal coupling functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The cooling plate structure uses composite materials that combine electrical insulation properties with thermal conductivity. This allows the cooling plate to maintain electrical isolation from the windings while still effectively conducting heat away from the coil device.

Inventive Principle:

Principle #40Composite materials

3Temperature

If cooling channels extend around all coil windings to improve heat dissipation, then thermal conductivity is improved, but structural space requirements increase

Engineering Contradiction:

Improveheat dissipationVSAvoidstructural space

Core Design Contradiction:

TemperatureVSVolume of stationary object

Solution Approach 1:

Multiple cooling channels are merged into a single integrated cooling plate structure that serves all coil windings simultaneously. This consolidation provides comprehensive cooling coverage without requiring separate cooling components for each winding, thus improving heat dissipation while controlling the overall structural volume.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The cooling channels are arranged in a planar configuration within the cooling plate, utilizing two-dimensional space efficiently. This allows the cooling channels to extend around multiple windings without requiring additional three-dimensional volume, thus providing comprehensive cooling while minimizing structural space requirements.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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

Enhances heat dissipation efficiency, reduces structural space requirements, and minimizes eddy currents, leading to improved mechanical stability and reduced weight, while maintaining effective electrical insulation and thermal conductivity.

Implementation Method 1

the cooling plate (2) is thermally coupled to at least one end face (400) of one of the coil windings (4)

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the cooling plate (2) has a cooling channel (24) which extends at least partially around each of the N coil windings (24)

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 3

incorporating an electrically insulating layer to minimize electrical interference

Methodology Applied

Scientific EffectElectrical insulation: Electrical Resistance

Data Source

PatentUS11443882B2Coil device

Publication Date: 2022.09.13 SIEMENS AG

AI summary

Various embodiments include a coil device for a power converter, the device comprising: a cooling plate; and a plurality N≥3 of coil windings. The cooling plate is thermally coupled to at least one end face of one of the plurality of coil windings. The coil windings are spatially offset from one another by an angle of 2π/N. The cooling plate defines a cooling channel extending at least partially around each of the plurality of coil windings.