Busbar with Tailored Perforation Sizes for Thermal Path

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Solution Overview

Problem

The miniaturization of electric power converters leads to increased heat/current density, which results in thermal management challenges, particularly in the connection between smoothing DC link capacitors and power modules, where traditional busbar designs fail to effectively manage heat flow and reduce temperature gradients.

Innovation Solution

A busbar design featuring perforations of varying sizes along an arcuate axis, with smaller perforations closer to the power module end and larger ones further away, to increase the effective heat flow area and reduce thermal resistance, while maintaining electrical connectivity through aligned connector orifices and bolts, and incorporating multiple layers with insulation and cooling plates to manage heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If traditional busbar designs are used, then electrical connectivity is maintained, but thermal resistance is high and heat flow is not effectively managed

Engineering Contradiction:

Improvethermal resistanceVSAvoidbusbar structure

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The busbar incorporates perforations of varying sizes at different locations, with smaller perforations near the power module end and larger perforations further away, creating local variations in thermal conductivity to optimize heat flow paths from the capacitor to the cooling plate

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The busbar is divided into multiple layers with different electrical isolation characteristics, allowing independent optimization of thermal paths for different electrical circuits while maintaining electrical connectivity where needed

Inventive Principle:

Principle #1Segmentation

2Volume of moving object

If miniaturization is applied to reduce converter size, then device footprint is reduced, but heat/current density increases leading to thermal management challenges

Engineering Contradiction:

Improveconverter sizeVSAvoidheat density

Core Design Contradiction:

Volume of moving objectVSTemperature

Solution Approach 1:

The patent transitions from planar heat dissipation to three-dimensional heat management by stacking multiple busbar layers with alternating electrical isolation, creating vertical thermal paths to the cooling plate while maintaining compact horizontal footprint

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Perforation sizes are locally optimized based on thermal requirements, with larger perforations positioned to maximize heat flow from high-density areas while maintaining structural integrity in other regions

Inventive Principle:

Principle #3Local quality

3Temperature

If perforations are made larger to increase heat flow area, then thermal resistance decreases, but electrical connectivity is compromised

Engineering Contradiction:

Improveheat flow areaVSAvoidelectrical connectivity

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The busbar is segmented into multiple layers where certain layers are electrically isolated, allowing perforations to pass through isolated layers for thermal purposes while maintaining electrical connectivity in non-isolated layers

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Electrically isolated layers act as thermal mediators, conducting heat from capacitors to the cooling plate while blocking electrical current, thus enabling large perforations in thermally conductive paths without compromising electrical connectivity

Inventive Principle:

Principle #24Intermediary (Mediator)

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 effectively reduces thermal resistance and directs heat flow away from capacitors, maintaining operational temperatures within limits and preventing overheating, thereby ensuring efficient performance of the inverter system.

Implementation Method 1

increase the effective heat flow area and reduce thermal resistance

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3893378B1Busbar with tailored perforation sizes to provide thermal path

Publication Date: 2023.07.12 HAMILTON SUNDSTRAND CORP

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AI summary

Disclosed is an assembly including a busbar that includes: a first layer (110) that defines: first layer top and bottom surfaces (120, 130); first layer first and second ends (140, 150); and a first layer center region (160) between the first layer first and second ends (140, 150); and the first layer forms first layer perforations (170) of different sizes about the first layer center region (160) so perforations closer to the first layer first end (140) are smaller than perforations spaced apart therefrom; a second layer (180) that is disposed against and electrically isolated from the first layer bottom surface (130), wherein the second layer defines connector orifices (190) having a same size as each other that are aligned with the first layer perforations (170); and a first capacitor (200) supported against and electrically connected to the first layer top surface (120), wherein the first capacitor (200) includes busbar connectors (210) that respectively extend through the first layer perforations (170) to electrically connect with the connector orifices (190).