Capacitor Busbar Thermal Management in Power Electronic Subassembly

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Solution Overview

Problem

Existing power electronic systems face challenges in effectively cooling and thermally managing capacitor devices within their housing, leading to potential overheating and reduced reliability.

Innovation Solution

The power electronic subassembly incorporates a housing with an integrated cooling area, where a capacitor busbar system comprising two sheet-like metal bodies of different polarities is arranged closely adjacent with an insulation film for reliable potential separation, and a meandering cross-section design for enhanced thermal contact with the cooling area, allowing for efficient heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the capacitor device is arranged close to the cooling area for thermal management, then heat dissipation efficiency is improved, but the risk of overheating and reliability degradation increases

Engineering Contradiction:

Improveheat dissipation efficiencyVSAvoidcapacitor reliability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The capacitor busbar system is segmented into multiple regions: a first region with first polarity contact devices, a second region with second polarity contact devices, and a third region forming the cooling contact surface. This segmentation allows different portions of the busbar system to serve different functions (electrical connection vs. thermal management) simultaneously, enabling effective heat dissipation while maintaining electrical isolation and preventing overheating of capacitor components.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the capacitor busbar system are assigned different local properties: the first and second regions are optimized for electrical connectivity with contact devices, while the third region is optimized for thermal contact with the cooling area. This local differentiation allows the system to achieve both reliable electrical connections and effective heat dissipation without compromising capacitor reliability.

Inventive Principle:

Principle #3Local quality

2Temperature

If the capacitor busbar system is arranged closely adjacent to the cooling area, then thermal coupling is enhanced, but electrical insulation and potential separation become more difficult to maintain

Engineering Contradiction:

Improvethermal coupling efficiencyVSAvoidinsulation structure complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The capacitor busbar system performs multiple functions simultaneously: it provides electrical connection for contact devices, establishes potential separation between polarities, and serves as a thermal conduction path to the cooling area. The third region of the busbar system specifically provides thermal coupling while the insulated housing maintains electrical isolation, eliminating the need for separate insulation structures and reducing overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Device complexity

If the capacitor device is positioned away from the cooling area for safety, then electrical insulation is simplified, but heat dissipation effectiveness is reduced

Engineering Contradiction:

Improveinsulation structure simplicityVSAvoidheat dissipation effectiveness

Core Design Contradiction:

Device complexityVSTemperature

Solution Approach 1:

The capacitor busbar system acts as an intermediary element that bridges the capacitor device and the cooling area. The third region of the busbar system provides thermal coupling to the cooling area while the insulated housing maintains electrical isolation. This intermediary approach allows effective heat dissipation without requiring the capacitor device itself to be positioned close to the cooling area, maintaining simple insulation structures.

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 ensures reliable thermal management and heat dissipation for the capacitors, maintaining the capacitors at a safe distance from the cooling area while ensuring effective thermal coupling, thereby enhancing the reliability and performance of the power electronic subassembly.

Implementation Method 1

a second subportion, which is in thermal contact with the cooling area

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

an insulation film is advantageously arranged between the first shaped metal body and the second shaped metal body

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Data Source

PatentUS9907215B2Power electronic subassembly with capacitor

Publication Date: 2018.02.27 SEMIKRON DANFOSS ELEKTRONIK GMBH & CO KG

AI summary

A power electronic subassembly having a housing and a capacitor arranged therein. The housing has an internally arranged cooling area, which is cooled by a cooling device integrated in the housing or an external cooling device. The capacitor has a contact device of a first polarity and a contact device of a second polarity and a capacitor busbar system. This capacitor busbar system comprises first and second sheet-like shaped metal bodies. The first metal body with the first contact device of the first polarity and the second metal body with the second contact device of the second polarity are electrically conductively connected. A first portion of the first metal body has a first subportion, which is arranged parallel to and at a distance from the cooling area, and a second subportion, which is in thermal contact with the cooling area, wherein the two subportions are connected by an intermediate portion.