Bus Bar Heat Sink Layout for Compact Inverter Cooling

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional inverter devices face challenges in effectively dissipating heat from bus bars connected to smoothing capacitors and power semiconductor modules while maintaining a compact size and reducing inductance, which affects the rigidity and heat dissipation performance.

Innovation Solution

A bus bar heat dissipation structure that integrates a pair of bus bars with a heat sink and insulating members, using a resin member to secure insulation and rigidity, allowing heat to be dissipated through a case-side fixing leg part, thereby improving heat dissipation and reducing the device's size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the cross-sectional area of bus bars is increased to improve heat dissipation, then heat dissipation performance is improved, but the space required increases and the compactness of the inverter device deteriorates

Engineering Contradiction:
Improveheat dissipation performanceVSAvoiddevice size
Core Design Contradiction:
TemperatureVSVolume of moving object

Solution Approach 1:

A heat sink is introduced as an intermediary component between the bus bars and the inverter case. The heat sink receives heat from the bus bars through thermal contact and transfers it to the inverter case, enabling effective heat dissipation without requiring increased bus bar cross-sectional area, thus maintaining compact device dimensions

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If a large area heat sink is provided at the lower part of bus bars to improve heat dissipation, then heat dissipation performance is improved, but the device complexity and space occupation increase

Engineering Contradiction:
Improveheat dissipation performanceVSAvoidstructure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The inverter case serves multiple functions: it provides structural housing, electrical insulation between bus bars and ground, and acts as a heat dissipation surface. By utilizing the case's lower surface as a heat dissipation area through the heat sink, the design avoids adding separate large heat dissipation structures, thereby reducing overall device complexity

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

3Area of stationary object

If bus bars are integrally molded with resin to ensure insulation and save space, then insulation distance is ensured and space is saved, but heat dissipation capability deteriorates

Engineering Contradiction:
Improvespace utilizationVSAvoidheat dissipation capability
Core Design Contradiction:
Area of stationary objectVSTemperature

Solution Approach 1:

The heat sink acts as a thermal intermediary that contacts the resin-molded bus bars. It extracts heat from the bus bars through the resin interface and transfers it to the inverter case, enabling heat dissipation while maintaining the space-saving integral molding structure and its associated insulation benefits

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

Enhances the rigidity and heat dissipation performance of bus bars, reduces the inverter device's size, and shields electrical noise, ensuring effective heat management and component protection.

Implementation Method 1

a heat sink disposed between the pair of the bus bars along the pair of the bus bars

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4350969B1Bus bar heat dissipation structure and inverter device
Publication Date: 2025.11.26 MEIDENSHA CORP
  • EP4350969B1 patent drawingFigure 1
  • EP4350969B1 patent drawingFigure 2
  • EP4350969B1 patent drawingFigure 3(a)~3(d)

AI summary

In an inverter device 1, a pair of bus bars P and N are disposed along each other between a smoothing capacitor 2 and a power semiconductor module 3 and are connected to the smoothing capacitor 2 and the power semiconductor module 3. A heat sink 5 is disposed between the bus bars P and N along the bus bars P and N. Insulating members 6 are disposed between the bus bar P and the heat sink 5 and between the bus bar N and the heat sink 5. A part of the heat sink 5 is connected to a case 4 on which the power semiconductor module 3 is mounted.