Distributed Inverter Mounting for Rotating Electric Machine Thermal Management

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Solution Overview

Problem

Existing rotating electric machines face inefficiencies due to high power consumption and heating issues in inverters, leading to reduced lifespan and reliability, primarily caused by inadequate heat dissipation and thermal gradients.

Innovation Solution

The design disperses inverter components across multiple positions on the housing's periphery, with each inverter supplying current to distinct windings, and incorporates a common control circuit to reduce heat concentration and power consumption, while using cooling fins and recessed portions for efficient heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If inverter components are concentrated in a single location, then device complexity is reduced, but heat concentration increases causing temperature rise and reduced reliability

Engineering Contradiction:
Improveinverter reliabilityVSAvoidinverter temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The inverter components (power conversion devices) are segmented and distributed to multiple locations on the housing periphery instead of being concentrated in one location. Each power conversion device is positioned on a different flat portion, which divides the heat generation sources and enables better heat dissipation, thereby reducing temperature rise while maintaining system reliability.

Inventive Principle:
Principle #1Segmentation

2Temperature

If inverter components are dispersed to multiple locations, then heat dissipation is improved, but device complexity increases

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidinverter configuration complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The housing structure is designed with multiple identical flat portions that can universally accommodate power conversion devices. Each flat portion has the same structural characteristics and cooling capabilities, allowing the system to maintain simplicity in design while achieving heat dissipation through distribution. The standardized mounting interfaces and uniform thermal management approach reduce the complexity increase that would normally result from分散ed configuration.

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

3Temperature

If power conversion devices are positioned on housing periphery, then cooling efficiency is improved, but internal space utilization is reduced

Engineering Contradiction:
Improvecooling efficiencyVSAvoidhousing internal space
Core Design Contradiction:
TemperatureVSVolume of stationary object

Solution Approach 1:

Instead of placing power conversion devices in the internal space of the housing, the design utilizes the external peripheral surface of the housing for mounting. This dimensional transition from internal to external placement allows the internal volume to remain fully available for other purposes while the external surfaces provide adequate cooling through exposure to ambient air flow.

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

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 enhances the efficiency and reliability of the rotating electric machine by reducing thermal interference, allowing for smoother operation and improved cooling efficiency, even in the event of inverter failure, and reduces the risk of overheating.

Implementation Method 1

cooling fins and recessed portions for efficient heat dissipation

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

cooling fins and recessed portions for efficient heat dissipation

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentEP3331135B1Rotating electric machine
Publication Date: 2021.02.17 HITACHI IND EQUIP SYST CO LTD
  • EP3331135B1 patent drawingFigure 1
  • EP3331135B1 patent drawingFigure 2
  • EP3331135B1 patent drawingFigure 3

AI summary

A rotating electric machine is provided with: a housing; a stator positioned inside the housing; a rotor which is rotated by receiving magnetic flux from the stator; and a power conversion device for supplying a drive current to each coil of the stator. In the rotating electric machine, a plurality of said power conversion devices are positioned at respectively different flat portions formed on the outer perimeter of the housing, and the coil to which a first power conversion device among the plurality of said power conversion devices supplies a drive current and the coil to which a second power conversion device different from the first power conversion device supplies a drive current are different from each other. This makes it possible to provide a rotating electric machine assembly suitable for integrating a control device and other devices.