Multi-Phase Flexible Conductor Spacing for Homogeneous Current Distribution

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Solution Overview

Problem

Existing multi-phase electrical connection technologies, such as solid busbars and copper braids, suffer from inhomogeneous current density distribution due to skin and proximity effects, leading to high AC resistance and thermal overloads, which are costly and inefficient.

Innovation Solution

A device using multiple identical flexible conductors arranged in a specific configuration to achieve a homogeneous current density distribution, with conditions defining the conductor spacing to maximize current transport and minimize material usage, leveraging the skin and proximity effects for compensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If solid busbars are used to transmit large amounts of power, then power transmission capability is improved, but tolerance compensation capability deteriorates

Engineering Contradiction:
Improvepower transmission capabilityVSAvoidtolerance compensation capability
Core Design Contradiction:
PowerVSAdaptability or versatility

Solution Approach 1:

The solid busbar is segmented into multiple parallel flexible conductors (at least two conductors per phase), each capable of independent movement. This segmentation maintains high power transmission capability while enabling tolerance compensation through the flexible arrangement of individual conductors.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses composite structures combining flexible conductors with specific geometric arrangements and cross-sectional shapes (e.g., rectangular, triangular, or circular cross-sections). This composite approach achieves both high current carrying capacity and mechanical flexibility for tolerance compensation.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If conventional flexible connecting elements (aluminum or copper braids) are used to enable tolerance compensation, then adaptability is improved, but manufacturing cost deteriorates

Engineering Contradiction:
Improvetolerance compensation capabilityVSAvoidmanufacturing cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

Instead of custom-made braided structures, the invention segments the connection into multiple identical or similar flexible conductors that can be manufactured using standard processes. This reduces costs while maintaining flexibility and tolerance compensation capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses identical or similar flexible conductors for all phases, standardized in geometry and material properties. This homogeneity enables batch manufacturing and reduces costs compared to custom-made asymmetric braided structures.

Inventive Principle:
Principle #33Homogeneity

3Adaptability or versatility

If conventional flexible connecting elements are used in alternating current systems, then tolerance compensation is improved, but current density distribution deteriorates

Engineering Contradiction:
Improvetolerance compensation capabilityVSAvoidcurrent density distribution
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The invention optimizes the local geometry of each conductor (specific cross-sectional shapes and dimensions) to compensate for skin and proximity effects. By carefully designing the local properties of individual conductors and their spacing, homogeneous current density distribution is achieved despite AC effects.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention transitions from single solid conductors to multiple parallel conductors with optimized spacing and geometric arrangements. This dimensional change from 1D to 2D/3D arrangement allows control over current distribution patterns, reducing skin and proximity effects.

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

4Manufacturing precision

If multiple conductors are used to reduce displacement effects, then current density distribution is improved, but device complexity increases

Engineering Contradiction:
Improvecurrent density distributionVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention uses identical or similar flexible conductors standardized in geometry, material, and arrangement for all phases. This homogeneity simplifies design, manufacturing, and assembly despite using multiple conductors, reducing overall device complexity.

Inventive Principle:
Principle #33Homogeneity

Solution Approach 2:

The multiple flexible conductors serve multiple functions simultaneously: they transmit current, provide tolerance compensation through flexibility, and reduce skin and proximity effects through their geometric arrangement. This multi-functionality reduces the need for additional components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution results in a more homogeneous current distribution, reducing thermal loads and material costs, enabling efficient and cost-effective multi-phase electrical connections with a simple design.

Implementation Method 1

physical effects such as the so-called skin and proximity effects can mean that when they are used in alternating current systems, the current density within the connecting elements is not homogeneous

Methodology Applied
Scientific EffectSkin effect: Skin Effect

Implementation Method 2

When using several conductors, the proximity effect as a result of eddy currents caused by the voltages induced by changing magnetic fields in adjacent conductors leads to a further displacement effect

Methodology Applied
Scientific EffectProximity effect: Eddy Currents

Implementation Method 3

A device using multiple identical flexible conductors arranged in a specific configuration to achieve a homogeneous current density distribution, with conditions defining the conductor spacing to maximize current transport and minimize material usage, leveraging the skin and proximity effects for compensation

Methodology Applied
Scientific EffectSkin effect compensation: Skin Effect

Data Source

PatentEP3332464B1Device for producing a multi-phase electric connection and an arrangement having corresponding devices
Publication Date: 2020.03.04 SMA SOLAR TECH AG
  • EP3332464B1 patent drawingFigure 1
  • EP3332464B1 patent drawingFigure 2
  • EP3332464B1 patent drawingFigure 3

AI summary

The invention relates to a device (1) for producing a multi-phase electric connection, comprising at least one connecting element (2) per phase. Each connecting element (2) comprises two current rails (3) and a number (N) of identical flexible conductors (4) arranged in parallel in a plane connecting the two current rails (3) in an electrically conductive manner. A distance (a) of geometric center points of cross-sections of adjacent conductors (4) from one another is at least twice as great as an equivalent diameter (d, däqui ) of one of the conductors (4). Each current rail (3) has one each connection area (5) for electrically and mechanically connecting the connecting elements (2) to an electrical system, and the connecting elements (2) are arranged in parallel to one another. The geometric center points of the cross-sections of adjacent conductors (4) of adjacent connecting elements (2), which are assigned to different phases, are at a distance (b) from one another, which distance is in each case at most half of the product of the number (N) of the electrical conductors (4) minus 1, multiplied by the distance a of the conductors (4) of a phase amongst each other.