Roebel Winding with Alloy Shell for Superconducting Generator

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Solution Overview

Problem

High temperature superconducting windings in electric generators are prone to premature degradation and failure due to mechanical bending and tensile stresses, which are exacerbated by centrifugal, thermal, and fault-induced forces.

Innovation Solution

A winding design featuring a Roebel structure with conductive elements made from high temperature superconductive materials, such as yttrium barium copper oxide, wrapped in a protective shell of high strength alloy like stainless steel or INCONEL, which reduces the need for matrix resin and allows for a smaller radius of curvature, thereby enhancing structural integrity and resistance to stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If high temperature superconducting windings are used to improve generator efficiency, then energy conversion efficiency is improved, but mechanical strength and resistance to stress deteriorate due to sensitivity to bending and tensile stresses

Engineering Contradiction:

Improvegenerator efficiencyVSAvoidmechanical strength

Core Design Contradiction:

Use of energy by moving objectVSStrength

Solution Approach 1:

The patent uses composite materials by combining high temperature superconductive material with a protective shell made of high strength alloy. This composite structure allows the superconducting material to maintain its electrical properties while the protective shell provides the necessary mechanical strength to resist bending and tensile stresses during operation and fault conditions.

Inventive Principle:

Principle #40Composite materials

2Strength

If conventional windings are used, then mechanical strength is maintained, but generator efficiency deteriorates due to resistance losses

Engineering Contradiction:

Improvemechanical strengthVSAvoidgenerator efficiency

Core Design Contradiction:

StrengthVSUse of energy by moving object

Solution Approach 1:

The composite structure combines the electrical advantages of superconducting materials with the mechanical advantages of high strength alloys, achieving both high efficiency and mechanical strength simultaneously rather than having to choose one over the other.

Inventive Principle:

Principle #40Composite materials

3Power

If rotor windings are designed to circumscribe cylindrical rotor core, then generator power output is improved, but winding stress increases due to centrifugal and thermal mechanical loads

Engineering Contradiction:

Improvegenerator power outputVSAvoidwinding stress

Core Design Contradiction:

PowerVSStress or pressure

Solution Approach 1:

The patent employs curved Roebel conductor structures that are specifically designed to follow the cylindrical geometry of the rotor core. This curved configuration allows the windings to circumscribe the rotor core effectively for high power output while the protective shell and transposed structure distribute and reduce the centrifugal and thermal mechanical stresses.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The Roebel conductor structure segments the winding into multiple parallel conductors that are transposed along the length. This segmentation allows each individual conductor to experience reduced stress compared to a single solid conductor, while collectively providing the necessary current carrying capacity for high power output.

Inventive Principle:

Principle #1Segmentation

4Reliability

If over-speed protection is designed into the generator, then safety is improved, but centrifugal force loads on rotor coil windings increase beyond normal operating loads

Engineering Contradiction:

ImprovesafetyVSAvoidcentrifugal force

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The protective shell acts as a pre-designed protective measure that cushions the superconducting conductors against the increased centrifugal forces that will occur during over-speed fault conditions. This beforehand protection allows the generator to safely withstand over-speed events without damaging the delicate superconducting material.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 design improves the mechanical strength and durability of the windings, reducing the risk of failure under stress conditions and enabling a more compact generator design while maintaining effective cryogenic performance.

Implementation Method 1

high temperature superconductive materials

Methodology Applied

Scientific EffectSuperconductivity: Superconductivity

Implementation Method 2

high strength alloy suitable for cryogenic temperatures

Methodology Applied

Scientific EffectMechanical strength:

Data Source

PatentEP1971015B1Winding for use in high temperature superconducting generator

Publication Date: 2019.06.12 SIEMENS ENERGY INC

Figure 1~2
Figure 2A
Figure 3

AI summary

A winding for use in a superconducting electric generator having a rotating rotor assembly surrounded by a non-rotating stator assembly is provided. The winding comprises at least one conductor structure associated with a component in the superconducting electric generator. The conductor structure comprises a plurality of conductive elements formed from a high temperature superconductive material. At least a portion of the conductive elements is arranged in a transposed relationship. A protective shell is positioned about the conductive elements and formed from a high strength alloy suitable for cryogenic temperatures.