Power Conversion Device Casing with Segmented Refrigerant Grooves

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Solution Overview

Problem

Existing power conversion devices face challenges in downsizing due to component mounting on both sides of refrigerant flow passages, leading to increased space requirements and low heat dissipation performance, particularly for large heat-generating components like reactors and transformers, which experience long heat conduction paths and high thermal resistance.

Innovation Solution

A power conversion device design featuring a casing with a refrigerant flow passage groove and a groove cover, where electrical components are mounted on facing portions with distinct flow passage areas, allowing refrigerant to flow beneath and alongside components, enhancing cooling through heat transfer materials and optimized flow passage dimensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If components are mounted on both sides of the refrigerant flow passage, then the device can be downsized, but the heat dissipation performance deteriorates due to long heat conduction paths and high thermal resistance

Engineering Contradiction:
Improvedevice sizeVSAvoidheat dissipation performance
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

The refrigerant flow passage is segmented into multiple regions: a first flow passage region with a first cross-sectional area and a second flow passage region with a second cross-sectional area. This segmentation allows different components to be positioned in optimal locations for heat dissipation while maintaining compact device dimensions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different cross-sectional areas are provided at different locations of the refrigerant flow passage to match the heat generation characteristics of components mounted at those locations. Large heat-generating components are positioned in regions with larger cross-sectional areas for better cooling, while smaller components are in regions with smaller cross-sectional areas.

Inventive Principle:
Principle #3Local quality

2Device complexity

If the refrigerant flow passage has uniform cross-sectional area, then the structure is simple, but the cooling capacity is insufficient for large heat-generating components

Engineering Contradiction:
Improveflow passage structureVSAvoidcooling capacity
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The refrigerant flow passage is designed with non-uniform cross-sectional area, where the first flow passage region has a first cross-sectional area and the second flow passage region has a second cross-sectional area that is different from the first. This local variation in geometry optimizes heat dissipation for components with different heat generation characteristics.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The cross-sectional area parameter of the refrigerant flow passage is changed along its length to match the heat generation profile of mounted components. This parameter optimization enhances cooling capacity without requiring complex external cooling systems.

Inventive Principle:
Principle #35Parameter changes

3Weight of moving object

If electronic components are downsized, then the device weight is reduced, but the heat generation density increases requiring higher cooling capacity

Engineering Contradiction:
Improvedevice weightVSAvoidheat generation density
Core Design Contradiction:
Weight of moving objectVSTemperature

Solution Approach 1:

The refrigerant flow passage cross-sectional area is optimized to provide sufficient cooling capacity for high-density heat generation in downsized components. The first and second cross-sectional areas are specifically designed to match the heat generation characteristics of the mounted electronic components.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

A refrigerant-based liquid cooling system is used to efficiently remove heat from high-density electronic components. The refrigerant flow passage is designed with appropriate cross-sectional areas to ensure sufficient heat transfer capacity while maintaining compact device dimensions.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 design increases cooling capacity while downsizing the device, improving heat dissipation for high-heat-generating components and reducing assembly complexity, thus enhancing overall efficiency and reducing costs and weight.

Implementation Method 1

a refrigerant flow passage groove (27) formed in a refrigerant flow passage surface (22), which is a back side of the component mounting surface (21)

Methodology Applied
Scientific EffectHeat transfer: Convection

Implementation Method 2

enhancing cooling through heat transfer materials

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3518413B1Power conversion device
Publication Date: 2023.01.11 MITSUBISHI ELECTRIC CORP
  • EP3518413B1 patent drawingFigure 1~2
  • EP3518413B1 patent drawingFigure 3~4
  • EP3518413B1 patent drawingFigure 5~6

AI summary

In a power conversion device, a casing main body has a component mounting surface, on which electrical components are mounted, and a refrigerant flow passage surface, which is a back side of the component mounting surface. The refrigerant flow passage surface has a refrigerant flow passage groove. The component mounting surface has a first facing portion, which faces a lid, a second facing portion, which is adjacent to the first facing portion, and faces the lid farther away from the lid than the first facing portion, and a side surface portion, which is formed between the first facing portion and the second facing portion. The refrigerant flow passage groove has a first flow passage portion located on back sides of the first facing portion and the side surface portion, and a second flow passage portion located on a back side of the second facing portion.