Synchronous Superconductive Rotary Machine with Segmented Pole Units

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Solution Overview

Problem

Existing superconductive rotary machines have complex and costly designs due to the need for cryostats and high cooling capacities, which increase manufacturing costs and downtime, especially in direct drive wind turbines with many pole units.

Innovation Solution

A synchronous superconductive rotary machine design where the first pole units are operated at ambient temperature and the second pole units at cryogenic temperature, with thermally insulating support elements to reduce cooling requirements and allow for a compact, lightweight structure, and separate manufacturing of superconductive pole modules for easier assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If all pole units are operated at cryogenic temperature to use superconductive coils, then high current density and efficiency are achieved, but the mass to be cooled increases significantly and cooling capacity needs increase

Engineering Contradiction:
Improvecurrent densityVSAvoidmass to be cooled
Core Design Contradiction:
Use of energy by moving objectVSWeight of moving object

Solution Approach 1:

The rotor is segmented into first pole units with conventional coils and second pole units with superconductive coils. This segmentation allows only specific regions to be cooled cryogenically, reducing the total mass requiring cooling while maintaining high current density in the superconductive regions where it provides maximum benefit.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the rotor are assigned different operational temperatures and coil types based on local requirements. The second pole units use superconductive coils at cryogenic temperature where high current density is critical, while first pole units use conventional coils at ambient temperature, optimizing the overall system without requiring complete cryogenic cooling.

Inventive Principle:
Principle #3Local quality

2Temperature

If a complete cryostat system is used to cool all rotor components, then superconductive coils can be operated at required temperature, but the device complexity and manufacturing costs increase

Engineering Contradiction:
Improveoperating temperatureVSAvoidcooling system complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The cooling system is segmented to cool only the second pole units containing superconductive coils, rather than cooling the entire rotor. This reduces the complexity of the cryostat system and associated infrastructure while maintaining the required operating temperature for the superconductive components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Thermally insulating support elements are introduced as intermediaries between the cryogenically cooled second pole units and the ambient temperature rotor structure. These elements minimize heat transfer while allowing mechanical support, reducing the cooling load and simplifying the overall thermal management system.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Temperature

If the entire rotor structure is cooled to cryogenic temperature, then uniform cooling is achieved, but the cooling time and downtime increase

Engineering Contradiction:
Improvetemperature uniformityVSAvoidcooling time
Core Design Contradiction:
TemperatureVSLoss of time

Solution Approach 1:

Instead of cooling the entire rotor structure uniformly, only the specific second pole units containing superconductive coils are cooled to cryogenic temperature. This segmented approach dramatically reduces the thermal mass that must be cooled, decreasing cooling time and downtime while maintaining temperature uniformity in the cooled regions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second pole units with superconductive coils are pre-cooled to operating temperature before being installed in the rotor assembly. This preliminary cooling action reduces the overall cooling time required for the complete system, as the cryogenic components are already at operating temperature when assembled.

Inventive Principle:
Principle #10Preliminary action

4Strength

If thermally conductive support elements are used to attach pole units to the rotor, then mechanical strength is sufficient, but heat transfer to the ambient temperature rotor increases cooling requirements

Engineering Contradiction:
Improvemechanical strengthVSAvoidcooling capacity
Core Design Contradiction:
StrengthVSUse of energy by stationary object

Solution Approach 1:

Hybrid support structures combining thermally conductive and thermally insulating materials are used to attach the second pole units to the rotor. The thermally conductive portion provides mechanical strength and support, while the thermally insulating portion minimizes heat transfer from the ambient temperature rotor to the cryogenic pole units, reducing cooling capacity requirements.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The support elements have localized thermal properties: thermally conductive where mechanical strength is needed for structural integrity, and thermally insulating where heat transfer would increase cooling loads. This local differentiation of thermal properties optimizes both mechanical support and thermal management.

Inventive Principle:
Principle #3Local quality

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 reduces the mass to be cooled, decreases cooling capacity needs, and lowers manufacturing costs while maintaining high current density and efficiency, allowing for faster assembly and reduced downtime.

Implementation Method 1

the at least one rotor coil is configured to interact with at least one stator coil arranged in the stator via an electromagnetic field when the rotor is rotated relative to the stator

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the at least one second pole unit is spaced apart from the back iron by means of at least one thermally insulating support element

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 3

Superconducting rotary machines can be made significantly more compact and in a manner that requires less resources. However, such superconductive coils must be operated at an operating temperature below their critical temperature

Methodology Applied
Scientific EffectSuperconductivity: Superconductivity

Data Source

PatentEP3384585B1Synchronous superconductive rotary machine having a consecutive pole arrangement
Publication Date: 2021.04.21 ENVISION ENERGY DENMARK
  • EP3384585B1 patent drawingFigure 1
  • EP3384585B1 patent drawingFigure 2~3
  • EP3384585B1 patent drawingFigure 4~5

AI summary

The invention relates to a synchronously excited rotary machine with a superconductive rotor comprising a plurality of projecting first pole units of a magnetic material and a plurality of second pole units having superconductive coils wrapped around a core element of a magnetic material. Each second pole unit is positioned between two adjacent first pole units. The second pole units are spaced apart from aback iron and the first pole units via a plurality of thermally insulating support elements, wherein this spacing is evacuated so that it acts as magnetic air gap. An enclosed housing is provided on the back iron in which the first and second pole units are arranged, where- in the superconductive coils of the second pole units are in fluid communication with a cooling system. The first pole units and back iron are operated at an ambient temperature while the second pole units are operated at a cryogenic operating temperature.