Converter Cooling Unit Pressure Frame PCB Thermal Contact

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Solution Overview

Problem

Existing polyphase converters, such as three-phase inverters, face inadequate thermal contact between the printed circuit board and the heat sink due to insufficient compressive forces from pressure pads or screw connections, leading to reduced cooling efficiency during continuous or alternating load operations.

Innovation Solution

A pressure frame is introduced to enhance thermal contact by pressing the printed circuit board onto the heat sink, complementing the existing fastening means, ensuring full-surface contact and preventing lifting, thereby improving thermal contact and cooling efficiency with minimal construction effort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If pressure pieces are arranged on the longitudinal sides of the rectangular substrates, then the substrates can be pressed onto the heat sink, but the pressing is limited to longitudinal areas and thermal contact is insufficient during continuous or alternating load operation

Engineering Contradiction:
Improvecompressive forceVSAvoidthermal contact
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent transitions from point/line contact (pressure pieces on longitudinal sides) to surface contact by introducing a pressure frame that presses the entire printed circuit board surface onto the heat sink, achieving full-surface thermal contact and eliminating insufficient cooling during continuous or alternating load operation

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The pressure frame is divided into multiple pressing points or zones distributed across the printed circuit board surface, ensuring uniform pressure distribution and comprehensive thermal contact across the entire board area, rather than concentrating force at limited longitudinal locations

Inventive Principle:
Principle #1Segmentation

2Device complexity

If screw connections are arranged in the inner area of the rectangular structure, then the printed circuit board can be clamped and pressed onto the heat sink, but full contact cannot be ensured and thermal contact is reduced

Engineering Contradiction:
Improvefastening structureVSAvoidthermal contact
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent expands the fastening action from localized screw connection points to a distributed surface pressure system using a pressure frame, ensuring the entire printed circuit board surface maintains full contact with the heat sink, thereby achieving comprehensive thermal contact without increasing fastening complexity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The pressure frame serves multiple functions simultaneously: it distributes compressive force across the entire printed circuit board surface, maintains uniform thermal contact, and prevents localized overheating, thereby enhancing thermal management effectiveness without adding significant structural complexity

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

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

The pressure frame ensures reliable full-surface pressing and clamping of the printed circuit board on the heat sink, enhancing thermal contact and cooling performance while reducing assembly effort and potential leakage inductance issues.

Implementation Method 1

the power module being formed by a printed circuit board which rests on a heat sink with a side opposite the power semiconductors and by means of at least one fastening means, in particular a screw connection, can be brought into thermal contact with the heat sink

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2328390B1Converter with a cooling unit
Publication Date: 2016.08.31 STILL GMBH
  • EP2328390B1 patent drawingFigure 1
  • EP2328390B1 patent drawingFigure 2
  • EP2328390B1 patent drawingFigure 3

AI summary

The converter (1) has a power module (3) formed from a printed circuit board (6) designed as an insulated metal substrate printed circuit board. The circuit board rests upon a cooling body (21) with a side lying opposite to power semiconductors (7). The circuit board is brought into thermal contact with the body by a screw connection and is fixed at the body. A pressure frame (25) is provided for additional pressing of the circuit board against the body. A plate-shaped board (4) and the circuit board are electrically and mechanically interconnected by surface-mounted soldering pins (10a, 10b).