Wind Turbine Winding Switching for Low-Speed Blade Fitting Torque

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Solution Overview

Problem

Existing wind turbine assembly and disassembly processes require high torque for hub rotation, which is challenging with standard converters that reduce power at low frequencies, leading to insufficient torque for leaf mounting.

Innovation Solution

A wind power generator with a winding divided into parts, connected by a switching device that allows parallel operation during normal generator operation and series connection during leaf assembly, along with a bidirectional converter capable of operating at frequencies below 10 Hz.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the converter operates at very low frequencies during blade assembly, then the hub can be rotated for blade mounting, but the current becomes too high for the semiconductor components, requiring current reduction of 50 to 70 percent

Engineering Contradiction:
Improvehub rotation speedVSAvoidconverter component reliability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The converter dynamically adjusts its operating parameters based on the operational state. During blade assembly at very low frequencies (below 10 Hz), the converter operates in motor mode with reduced current to protect semiconductor components. During normal operation, it switches to generator mode with full current capability, optimizing performance for each specific operational phase.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the winding parts are connected in parallel during normal operation, then the current through each winding part is reduced, but the torque available for blade mounting becomes insufficient

Engineering Contradiction:
Improveconverter operation reliabilityVSAvoidtorque for hub rotation
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The switching device dynamically reconfigures the winding connection topology based on operational requirements. In parallel connection during normal generator operation to reduce current and heat. In series connection during blade assembly to maximize torque output for hub rotation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The electrical parameters of the generator are changed by altering the winding configuration. Parallel connection provides lower current and reduced torque, while series connection provides higher current and increased torque, allowing the system to adapt to different operational demands.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the converter reduces current at low frequencies to protect semiconductor components, then the components are protected from overload, but the torque available from the generator becomes insufficient to rotate the hub

Engineering Contradiction:
Improvesemiconductor component reliabilityVSAvoidtorque for blade assembly
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The converter operates in two distinct dynamic modes: motor mode for blade assembly with reduced current protection, and generator mode for normal operation with full power capability. This dynamic switching allows the system to protect components during low-speed operation while maintaining full torque capability when needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The same converter and generator system performs multiple functions: generating electricity during normal operation and providing controlled motor torque during blade assembly. The switching device and bidirectional converter enable this multi-functionality, allowing one system to serve both power generation and blade assembly purposes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 configuration enables high torque generation necessary for leaf mounting by switching the winding parts into series, while maintaining efficient operation during normal generator operation, thus overcoming the limitations of standard converters.

Implementation Method 1

the wind power generator is motor-operated in the blade mounting state of the winding parts

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the converter supplies a current for the winding with a frequency of less than 10 Hz, and in particular less than 1 Hz

Methodology Applied
Scientific EffectElectromagnetic torque: Lorentz Force

Data Source

PatentEP2800898B2Blade fitting method for a wind power generator
Publication Date: 2025.04.02 FLENDER GMBH
  • EP2800898B2 patent drawingFigure 1~2

AI summary

The intention is to make it possible using simple means to make available a high motor torque for blade fitting in a wind power generator. For this purpose, a wind power generator is proposed which has a winding which is associated with one phase of a current to be generated, wherein the winding is divided into a first winding element (WT1) and a second winding element (WT2). A switching device (S) is connected to the winding and can be used to connect the first winding element (WT1) and the second winding element (WT2) in parallel with one another in an operating state and in series with one another in a blade fitting state.