Composite Magnetic Core Wires for Low-Loss Electric Machines

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Solution Overview

Problem

Conventional iron cores in electric machines suffer from efficiency losses and heat generation, making it difficult to evaluate and design these machines effectively, and materials like silicon steel have limitations due to high thermal expansion and magnetostriction, leading to increased torque ripple, noise, and vibration.

Innovation Solution

A composite material assembly comprising magnetic microwires, nanowires, or chains of nanoparticles/microparticles embedded in a nonmagnetic polymeric matrix, which provides low core losses, high permeability, and reduced thermal expansion, used in rotor-stator assemblies and electromagnetic shields to enhance efficiency and reduce stress effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional iron cores are used in electrical machines, then the structure is simple and cost is low, but core losses increase and efficiency decreases

Engineering Contradiction:

Improvecore lossesVSAvoidmaterial structure complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent applies composite materials by embedding magnetic microwires or nanowires within a nonmagnetic polymeric matrix. This composite structure reduces core losses through the magnetic material's inherent properties while the polymeric matrix provides insulation and structural support, achieving lower energy losses compared to conventional iron cores without excessive complexity

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent segments the magnetic material into discrete microwires or nanowires that are individually embedded in the polymeric matrix. This segmentation allows each wire to function independently, reducing eddy current losses and improving overall core performance while maintaining a manageable structural complexity

Inventive Principle:

Principle #1Segmentation

2Object-affected harmful factors

If silicon steel is used as soft magnetic material, then flux density is high and cost is low, but thermal expansion and magnetostriction increase leading to torque ripple and vibration

Engineering Contradiction:

Improvethermal expansion and magnetostriction effectsVSAvoidperformance stability under thermal and magnetic stress

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent introduces a nonmagnetic polymeric matrix as an intermediary material that embeds the magnetic microwires or nanowires. This matrix acts as a buffer that reduces thermal expansion effects and magnetostriction, preventing direct stress transmission that would cause torque ripple and vibration, thereby improving performance stability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical parameters of the core material by using magnetic microwires or nanowires with specific diameter ranges (1-500 microns for microwires, 1-500 nanometers for nanowires) and controlling their volume fraction (1-50%). These parameter changes result in reduced thermal expansion and magnetostriction compared to conventional silicon steel

Inventive Principle:

Principle #35Parameter changes

3Productivity

If magnetic microwires or nanowires embedded in polymeric matrix are used, then core losses are reduced and efficiency is increased, but manufacturing complexity increases

Engineering Contradiction:

Improveelectrical machine efficiencyVSAvoidmanufacturing process simplicity

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by pre-forming the magnetic micrawires or nanowires and preparing the polymeric matrix before assembly. The magnetic wires are manufactured separately with controlled properties, then embedded in the polymeric matrix in a systematic manner, allowing for optimized manufacturing processes that balance efficiency improvement with manufacturing feasibility

Inventive Principle:

Principle #10Preliminary action

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 composite material significantly reduces core losses, increases efficiency, and minimizes stress effects in electrical machines by offering low thermal expansion and high permeability, resulting in improved torque, reduced noise, and vibration, while being lighter than conventional materials.

Implementation Method 1

the composite material significantly reduces core losses, increases efficiency, and minimizes stress effects in electrical machines by offering low thermal expansion and high permeability

Methodology Applied

Scientific EffectPermeability:

Implementation Method 2

the core material should ideally have low thermal expansion and magnetostriction to minimize the stress effects

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

strain responses to temperature and the magnetic field, known as thermal expansion and magnetostriction, respectively

Methodology Applied

Scientific EffectMagnetostriction: Magnetostriction

Data Source

PatentUS11739402B2Magnetic particles or wires for electrical machinery

Publication Date: 2023.08.29 THE UNIVERSITY OF AKRON

AI summary

An electrical composite assembly includes a plurality of composite material macro-wires each including a magnetic material embedded within a nonmagnetic matrix. The magnetic material can be selected from magnetic microwires, magnetic nanowires, chains of magnetic nanoparticles, and chains of magnetic microparticles. The plurality of composite material macro-wires are included in an electrical component, where the electrical component is selected from a rotor, a stator, and an electromagnetic shield.