Power Converter Switching Device Spacing for Linear Drive Thermal Management

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Solution Overview

Problem

Linear drive systems experience localized heating issues due to elevated currents required for speed changes and load interactions, limiting their capacity and efficiency.

Innovation Solution

The power converter design includes pairs of adjacent switching devices connected to coils with an additional coil between them, spreading heat generation and reducing localized heating by spacing out the elevated current handling across multiple modules.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If multiple adjacent switching devices are connected to adjacent coils to control mover speed changes, then the linear drive system can achieve the required electromagnetic force for acceleration and deceleration, but localized heating occurs in the switching devices due to elevated currents

Engineering Contradiction:
Improveelectromagnetic force for speed controlVSAvoidlocalized heating in switching devices
Core Design Contradiction:
ForceVSTemperature

Solution Approach 1:

The patent divides the track into multiple segments with coils grouped into different sets. Switching devices are distributed across these segments rather than concentrated in one location. This segmentation allows the system to achieve required electromagnetic force for speed control while distributing heat generation across multiple spatial locations, preventing localized overheating.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements different switching device configurations for different track segments. Each segment can be optimized with appropriate switching devices based on local requirements. This allows adjacent switching devices to handle elevated currents when needed while other devices remain cooler, creating local quality variations that resolve the heating problem.

Inventive Principle:
Principle #3Local quality

2Speed

If multiple adjacent coils are activated to create smooth speed transitions, then the mover acceleration and deceleration become smoother, but the current demand on adjacent switching devices increases

Engineering Contradiction:
Improvesmoothness of speed transitionVSAvoidcurrent demand on switching devices
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The patent segments the coil activation into different groups distributed along the track. When smooth speed transitions are required, multiple coils from different segments can be activated simultaneously or sequentially. This segmentation allows smooth acceleration and deceleration while distributing the current demand across multiple switching devices rather than concentrating it in adjacent devices.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent distributes coils and switching devices along the spatial dimension of the track rather than concentrating them in one location. This spatial distribution allows the system to activate multiple coils for smooth speed transitions while the current demand is spread across different spatial locations, effectively using the track length as an additional dimension to manage current demand.

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 design effectively reduces localized heating within the power converter, enhancing the capacity and efficiency of linear drive systems by distributing heat generation and improving control over switching devices.

Implementation Method 1

each mover includes multiple permanent magnets mounted to the mover. The permanent magnets are operative to propel the mover along the track responsive to an electromagnetic field

Methodology Applied
Scientific EffectElectromagnetic field interaction: Lorentz Force

Implementation Method 2

The coils are distributed along a length of the track segment, and each coil generates at least a portion of the electromagnetic field propelling each mover along the track

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3301809B1Method and apparatus for interleaved switching of track segments in a motion control system
Publication Date: 2020.11.11 ROCKWELL AUTOMATION TECH INC
  • EP3301809B1 patent drawingFigure 1
  • EP3301809B1 patent drawingFigure 2
  • EP3301809B1 patent drawingFigure 3

AI summary

A power converter for a linear drive system having improved control of the switching devices to reduce the effects of localized heating within the power converter is disclosed. The linear drive system controls multiple movers along a track. Multiple coils are positioned adjacent to each other along the length of the track. Each coil is connected to a switching device within the power converter to energize and de-energize the coils. Pairs of adjacent switching devices are connected to coils that have at least additional coil located between the adjacent switching devices. Thus, adjacent switching modules do not conduct the same level of current and those switching modules that are required to conduct elevated levels of current are spaced apart from each other within the power converter. Consequently, the heat generated as a result of the elevated current and increased switching is similarly spread out within the power converter.