Modular Direct-Drive Generator Torque Mass Trade-off

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Solution Overview

Problem

Large direct-drive wind turbines face challenges with high cost, mass, and complexity due to the need for high-torque generators, limiting their scalability and applicability in large systems, while existing direct-drive generator technologies are disadvantageous in cost but advantageous in energy yield and reliability compared to geared generators.

Innovation Solution

The development of a direct-drive electric machine with an optimized structure that reduces material usage, facilitates fabrication, transport, and maintenance by incorporating a transverse flux permanent magnet machine with a bearingless drive and modular design, which minimizes active and inactive materials, and employs hydrostatic bearings for reduced weight and energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a large-diameter high-torque generator is used in direct-drive wind turbines, then high torque rating is achieved, but mass and manufacturing cost significantly increase

Engineering Contradiction:
Improvetorque ratingVSAvoidgenerator mass
Core Design Contradiction:
ForceVSWeight of moving object

Solution Approach 1:

The generator is divided into multiple independent modules arranged in a circular configuration. Each module contains its own permanent magnet rotor and stator components. The modules are connected to a common shaft through flexible couplings, allowing independent assembly and reducing transportation constraints while achieving high torque through modular scaling.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a conventional single large-diameter generator to a multi-module circular arrangement. The modules are positioned at different angular positions around a central shaft, creating a three-dimensional modular structure that achieves high torque rating through spatial distribution rather than increasing the diameter of a single generator.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Force

If a large-diameter high-torque generator is used in direct-drive wind turbines, then high torque rating is achieved, but manufacturing cost significantly increases

Engineering Contradiction:
Improvetorque ratingVSAvoidmanufacturing cost
Core Design Contradiction:
ForceVSEase of manufacture

Solution Approach 1:

The generator is divided into multiple independent modules arranged in a circular configuration. Each module contains its own permanent magnet rotor and stator components. The modules are connected to a common shaft through flexible couplings, allowing independent assembly and reducing transportation constraints while achieving high torque through modular scaling.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the structural parameters from a single large generator to multiple smaller modular units. This parameter change allows standardization of module components, enabling economies of scale in manufacturing and reducing overall cost while maintaining high torque rating through increased module quantity.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If conventional bearing systems are used in direct-drive generators, then rotational support is provided, but device complexity and maintenance requirements increase

Engineering Contradiction:
Improverotational supportVSAvoidbearing system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent removes the conventional bearing system from the generator structure. Instead of using bearings to support the rotor on the shaft, the design uses a bearingless configuration where the rotor is suspended magnetically or mechanically supported through alternative means, eliminating the bearing components and their associated complexity and maintenance requirements.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The support function traditionally performed by bearings is merged into the overall modular structure. The flexible couplings and modular arrangement provide both torque transmission and rotational support functions, combining multiple functions into integrated components rather than separate bearing assemblies.

Inventive Principle:
Principle #5Merging (Combining)

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 solution enables the reduction of manufacturing costs, improves scalability, and maintains high energy yield and reliability by maximizing force density, minimizing material usage, and allowing continuous power production even with module faults through modular design and efficient bearing systems.

Implementation Method 1

transverse flux permanent magnet machine

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

maximizing force density

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Implementation Method 3

employs hydrostatic bearings for reduced weight and energy consumption

Methodology Applied
Scientific EffectHydrostatic pressure: Hydraulic Press

Data Source

PatentEP2479876B1Direct-drive electric equipment
Publication Date: 2016.01.06 KOREA ELECTROTECH RES INST
  • EP2479876B1 patent drawingFigure 1
  • EP2479876B1 patent drawingFigure 2(a)~3
  • EP2479876B1 patent drawingFigure 4(a)~4(b)

AI summary

The present invention provides a direct-drive electric machine such as a generator and a motor comprising a rotor or a mover and a stator. The direct-drive electric machine is configured with a plural-module combination structure in which the rotor or the mover and the stator are mutually combined such that a plurality of modules form one phase, respectively.