Laminated Electromagnetic Actuator Reduces Eddy Current Losses

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Solution Overview

Problem

Miniature circuit breakers (MCBs) experience excessive losses and overheating due to higher-order harmonics in power electronics applications, leading to potential failure, as existing designs are not optimized to handle these frequencies effectively.

Innovation Solution

An electromagnetic actuator with an electrically conductive armature and core made of magnetizable material, coupled by a magnetic field and an electric coil, incorporates an electrically conductive layer to reduce eddy current losses by directing induced currents away from the core and armature, using materials like copper or aluminum for high conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If solid steel core and armature are used in the electromagnetic actuator, then magnetic coupling and force generation are improved, but eddy current losses increase significantly under higher-order harmonics

Engineering Contradiction:
Improvemagnetic forceVSAvoideddy current losses
Core Design Contradiction:
ForceVSLoss of energy

Solution Approach 1:

The solid steel core and armature are segmented into thin laminated layers insulated from each other. This segmentation interrupts the path of eddy currents, reducing their magnitude and associated energy losses while maintaining the magnetic coupling effectiveness between core and armature.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The electrical resistance parameter of the core and armature paths is changed by introducing insulating layers between conductive laminations. This increases the effective resistance to eddy current flow, reducing power losses under harmonic conditions while preserving magnetic force generation capability.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the electromagnetic actuator is designed for mains frequency only, then device simplicity is maintained, but performance deteriorates under higher-order harmonics from power electronics

Engineering Contradiction:
Improveactuator structureVSAvoidoperational reliability under harmonics
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The actuator components are segmented into laminated structures that specifically address harmonic frequency effects. This segmentation adds minimal structural complexity while significantly improving reliability under power electronics-generated harmonic conditions by reducing eddy current losses.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the actuator are given different structural qualities - the core and armature use laminated construction to reduce eddy currents, while maintaining solid magnetic pathways. This local differentiation allows the actuator to handle harmonic frequencies effectively without over-complicating the overall design.

Inventive Principle:
Principle #3Local quality

3Temperature

If eddy current losses are reduced through material or structural changes, then overheating is prevented, but manufacturing complexity increases

Engineering Contradiction:
Improvethermal managementVSAvoidmanufacturing simplicity
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The core and armature are constructed from stacked laminated sheets that can be manufactured separately and assembled. This segmentation approach prevents overheating by reducing eddy currents while maintaining relatively simple manufacturing processes through standard lamination techniques used in electrical machine construction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The actuator uses composite construction combining conductive magnetic material layers with insulating layers. This composite structure reduces eddy current losses and prevents overheating while using well-established manufacturing methods for laminated electrical components, balancing thermal management with manufacturing ease.

Inventive Principle:
Principle #40Composite materials

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 solution significantly reduces electrical losses and prevents overheating, maintaining the actuator's robustness and compact size, even under high-frequency harmonic conditions, thereby extending the MCB's operational lifespan and reliability.

Implementation Method 1

an electric coil configured to generate the magnetic field

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

eddy currents induced to the electrically conductive material of the electromagnetic actuator by the generated magnetic field

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Data Source

PatentEP4036952A1Electromagnetic actuator for triggering a circuit breaker
Publication Date: 2022.08.03 ABB (SCHWEIZ) AG
  • EP4036952A1 patent drawingFigure 1
  • EP4036952A1 patent drawingFigure 2a~2b
  • EP4036952A1 patent drawingFigure 3~5

AI summary

An electromagnetic actuator for triggering a circuit breaker, is provided with: an electrically conductive armature comprising magnetizable material, wherein the armature is movable arranged within the electromagnetic actuator for triggering the circuit breaker; an electrically conductive core comprising magnetizable material, configured to be operational coupled to the armature by a magnetic field; an electric coil configured to generate the magnetic field; and an electrically conductive layer configured and arranged within the electromagnetic actuator to reduce electrical losses of eddy currents induced to the electrically conductive material of the electromagnetic actuator by the generated magnetic field.