Rotary Electrical Machine Thermal Management via Transferring Elements

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Solution Overview

Problem

High power electrical machines with low internal resistance electronic components face heat dissipation challenges, particularly in sealed types, where circulating currents due to the Joule effect cause significant losses, and the printed circuit's limited operating temperature becomes a weak link.

Innovation Solution

The implementation of surface-mounted transferring elements with high thermal conductivity, connected directly to MOSFETs, which face the cap and dissipate heat efficiently, along with a thermally conductive paste to maximize heat exchange, prevents heat from being transferred to the printed circuit, thereby enhancing thermal reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If electronic power components with lower internal resistances are used to increase power output and efficiency, then power output and efficiency are improved, but heat generation from circulating currents increases due to the Joule effect

Engineering Contradiction:
Improvepower outputVSAvoidheat loss
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent extracts the heat dissipation function from the printed circuit board by introducing dedicated heat sinks directly coupled to the electronic power components. This separation allows the PCB to focus on electrical connections while specialized components handle thermal management, resolving the contradiction between high power output and heat generation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces thermal paste as an intermediary substance between the electronic power components and heat sinks. This mediator improves thermal contact and heat transfer efficiency, allowing the system to handle higher power outputs without excessive heat accumulation in the PCB.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If heat dissipation structures are added to manage thermal loads, then thermal reliability is improved, but device complexity increases

Engineering Contradiction:
Improvethermal reliabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the heat sink structure with the existing casing or housing of the electrical machine. By integrating thermal management into existing structural components rather than adding separate assemblies, the design improves thermal reliability while minimizing increases in device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent designs the cap as a multi-functional component that serves both as a structural closure and as a heat dissipation element. This universal approach allows the same component to fulfill multiple functions, improving thermal management without adding extra parts or complexity.

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

3Ease of manufacture

If electronic components are mounted on the printed circuit, then ease of manufacture is improved, but the printed circuit becomes a weak link due to its lower maximum operating temperature

Engineering Contradiction:
Improveassembly easeVSAvoidthermal reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent segments the thermal management approach by providing dedicated heat sinks for each high-power electronic component rather than relying on the PCB's thermal capacity. This segmentation allows each component to be optimized for its specific thermal requirements while maintaining the ease of PCB-based assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses thermal paste as an intermediary to improve heat transfer from the electronic components to the heat sinks. This mediator enables effective thermal management without requiring direct soldering or mechanical attachment that would compromise the PCB or component integrity.

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 solution effectively disperses heat generated by electronic components, preventing overheating and maintaining efficiency in high power applications by redirecting heat away from the printed circuit, thus improving thermal reliability and performance.

Implementation Method 1

a thermally conductive paste is inserted between the electronic components and the cap so as to act as a dissipator thereby maximising the heat exchange between the cap and the components

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the cap of the electrical machine forms a transferring element, that is, a component for dispersing the heat generated by the electronic module

Methodology Applied
Scientific EffectHeat dissipation: Conduction (thermal)

Implementation Method 3

the circulating currents in the electronic power components can cause relatively high losses due to the Joule effect

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP2957020B1Electrical machine
Publication Date: 2019.12.04 SPAL AUTOMOTIVE
  • EP2957020B1 patent drawingFigure 1~2
  • EP2957020B1 patent drawingFigure 3
  • EP2957020B1 patent drawingFigure 4~5

AI summary

A rotary electrical machine incorporating an electronic module (8) comprising a printed circuit (13) mounted with a plurality of surface mounted electronic components (11) and a plurality of pin-through-hole electronic components (12); the electrical machine comprises a dissipator (9) for dispersing the heat generated by the electronic module (8); the surface mounted electronic components (11) and the pin-through-hole electronic components (12) are mounted between the printed circuit (13) and the dissipator (9); the electronic module (8) also comprises a transferring element (19), also mounted between the printed circuit (13) and the dissipator (9), in thermal contact with at least one of the surface mounted electronic components (11); the transferring element (19) is designed to disperse the heat generated by the surface mounted electronic components (11) towards the dissipator (9) with the aid of a thermally conductive and electrically isolating filler material (24) inserted between the transferring element (19) and the dissipator (9).