Trapped-Field Magnet Rotor Design for High Power Density

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Solution Overview

Problem

Current high-temperature superconductor (HTS) rotors and machines, while offering modest improvements in size and efficiency over traditional permanent magnet (PM) rotors, come with a high premium cost and are not efficiently activated, limiting their practical application.

Innovation Solution

The development of trapped-field magnet (TFM) rotors and synchronous machines that utilize YBCO pucks with specific configurations and activation methods, including the use of slip-ring couplings and cryogenic cooling, to generate and maintain a magnetic field, allowing for efficient magnetization and operation of the TFM bulks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high-temperature superconductor (HTS) rotors are used, then size and efficiency are improved, but cost increases significantly

Engineering Contradiction:

ImproveefficiencyVSAvoidcost

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent changes the material parameters by using YBCO bulk superconductors with specific critical current density thresholds (greater than 300 kA/cm² at 77K and 1 Tesla) to achieve high efficiency while controlling costs through parameter optimization rather than using expensive HTS wires

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by using permanent magnets only in specific regions where they are most effective (rotor poles facing the stator), rather than throughout the entire rotor, thereby reducing material costs while maintaining efficiency

Inventive Principle:

Principle #3Local quality

2Volume of moving object

If HTS rotors are used, then size is reduced, but cost increases significantly

Engineering Contradiction:

ImprovesizeVSAvoidcost

Core Design Contradiction:

Volume of moving objectVSEase of manufacture

Solution Approach 1:

The patent achieves size reduction by optimizing the volume and configuration of YBCO bulk superconductors and permanent magnets, using parameter changes in material selection and geometric arrangement to minimize volume while controlling costs

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The rotor is segmented into discrete permanent magnet pieces positioned in specific locations, allowing for optimized material usage and reduced overall size compared to traditional winding-based rotors

Inventive Principle:

Principle #1Segmentation

3Power

If TFM bulks are used, then power density is improved, but device complexity increases

Engineering Contradiction:

Improvepower densityVSAvoidcomplexity

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The patent improves power density by selecting YBCO bulks with specific critical current density parameters (greater than 300 kA/cm² at 77K and 1 Tesla) and optimizing their configuration, achieving high power output while managing complexity through parameter specification

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The TFM bulks are designed to be self-magnetizing, eliminating the need for external magnetization equipment and complex activation procedures, thereby reducing device complexity while maintaining high power density

Inventive Principle:

Principle #25Self-service

4Productivity

If TFM bulks are used, then efficiency is improved, but ease of operation worsens due to activation requirements

Engineering Contradiction:

ImproveefficiencyVSAvoidease of operation

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The TFM bulks are pre-magnetized during manufacturing or assembly, performing the magnetization action in advance so that no complex activation procedure is needed during operation, thereby maintaining high efficiency while improving ease of operation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The TFM bulks are designed to be self-magnetizing through their inherent properties, eliminating the need for external magnetization systems and complex operational procedures, thus improving ease of operation while maintaining efficiency

Inventive Principle:

Principle #25Self-service

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 TFM rotors and machines achieve significant improvements in power density and efficiency, potentially reducing costs and enhancing performance by leveraging the high critical current density of YBCO materials, while maintaining a stable magnetic field over time with effective thermal management.

Implementation Method 1

trapped-field magnet (TFM) rotors, TFM synchronous machines, and methods of activating TFM bulks in a synchronous machine

Methodology Applied

Scientific EffectTrapped field magnetization: Magnetic Field

Implementation Method 2

leveraging the high critical current density of YBCO materials

Methodology Applied

Scientific EffectSuperconductivity: Superconductivity

Implementation Method 3

including the use of slip-ring couplings and cryogenic cooling

Methodology Applied

Scientific EffectCryogenic cooling: Cryogenics

Data Source

PatentUS9577503B2Rotating machines using trapped field magnets and related methods

Publication Date: 2017.02.21 TECO WESTINGHOUSE MOTOR CO

AI summary

Rotors with trapped-field magnet (TFM) bulks, machines with TFM rotors, and methods of activating and/or using machines with TFM rotors.