Folded DC Bus Tab Assembly for Low-Inductance Connections

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Prior art DC bus connections often suffer from parasitic inductances that increase the size or capacitance requirements of capacitors needed to filter ripple current or noise, necessitating an improved electronic assembly for direct current bus connections.

Innovation Solution

The electronic assembly features a DC bus connection with a folded outer tab and a bent inner tab, both composed of dielectric and conductive layers, which are connected using a clamp with elastically deformable members to reduce electrical resistance to approximately 3 micro-ohms, thereby minimizing inductance and enhancing mechanical and electrical reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional single bolt connections are used, then the device complexity is low, but the electrical resistance and inductance are high

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidconnection structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The connection structure is segmented into multiple functional components: clamp body, elastically deformable members, and multiple contact points. This segmentation allows each component to perform its specific function optimally, achieving low resistance and inductance while maintaining manageable complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The elastically deformable members are designed to change their physical parameters (deformation, contact pressure) under clamping force, transforming the connection from rigid to compliant. This parameter change enables adaptive contact pressure distribution, reducing electrical resistance and improving connection reliability

Inventive Principle:
Principle #35Parameter changes

2Reliability

If elastically deformable members with multiple contact points are used, then the electrical resistance is reduced to approximately 3 micro-ohms, but the manufacturing complexity increases

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The elastically deformable members function as flexible elastic elements that can be formed from sheet material or extruded profiles. This approach simplifies manufacturing compared to rigid multi-component assemblies, as the flexible members can be produced using standard forming and bending processes

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The clamp assembly combines different materials (conductive layers, dielectric layers, elastic materials) to achieve both electrical performance and mechanical properties. This composite approach allows optimization of each material for its specific function while maintaining ease of manufacture through standardized material selection

Inventive Principle:
Principle #40Composite materials

3Reliability

If folded tab and bent inner tab configuration are used, then the inductance is minimized, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidtab formation precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The folded outer tab and bent inner tab utilize curved geometries to minimize inductance by optimizing current path geometry. The curved paths reduce loop area and improve current distribution, achieving low inductance while the curves can be formed using standard bending processes rather than requiring precision machining

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Reliability

If multiple conductive and dielectric layers are used, then the mechanical and electrical reliability is enhanced, but the device complexity increases

Engineering Contradiction:
Improvemechanical and electrical reliabilityVSAvoidlayer structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The conductive and dielectric layers are merged into integrated laminated structures where multiple layers are bonded together to form unified components. This merging reduces the number of separate parts and assembly steps, achieving enhanced reliability through layered construction while maintaining manageable complexity through integration

Inventive Principle:
Principle #5Merging (Combining)

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 configuration reduces electrical resistance and inductance, providing a reliable and efficient DC connection with superior mechanical properties, outperforming conventional single bolt connections by achieving lower electrical resistance and reduced inductance values.

Implementation Method 1

a clamp with elastically deformable members to reduce electrical resistance

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

DC bus connection with a folded outer tab and a bent inner tab, both composed of dielectric and conductive layers

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3817528B1Electronic assembly with a direct current bus connection
Publication Date: 2023.09.06 DEERE & CO
  • EP3817528B1 patent drawingFigure 1
  • EP3817528B1 patent drawingFigure 2
  • EP3817528B1 patent drawingFigure 3

AI summary

A folded outer tab comprises a first outer dielectric layer and a second outer dielectric layer that contact or overlie an outer terminal, where the outer terminal is associated with a first polarity of the DC bus. A bent inner tab comprises a first inner dielectric layer and a second inner dielectric layer that contact or overlie an inner terminal, where the inner terminal is associated with a second polarity of the DC bus that is opposite the first polarity. The folded outer tab and the bent inner tab comprise electrically conductive faces, of opposite polarities, formed of exposed portions of the outer terminal and the inner terminal.