Windmill Pitch Angle Controller for Load Reduction

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Solution Overview

Problem

Conventional wind turbine pitch-angle control methods result in aerodynamic load imbalances when blades are halted, as they are moved to a feathering position from different initial angles, leading to increased loads on the turbine.

Innovation Solution

A method and device for individually controlling wind turbine blade pitch angles, where the blades are matched to a representative angle closest to the feathering position before being moved collectively to that position, using adjusted speed controls to efficiently synchronize their angles and reduce aerodynamic load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If individual pitch control is used to move blades to feathering position, then blade independence is improved, but aerodynamic load imbalance increases

Engineering Contradiction:

Improveblade independenceVSAvoidaerodynamic load imbalance

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by matching the pitch angles of all blades to a reference blade's angle before moving them to the feathering position. This preliminary matching step ensures that blades are synchronized beforehand, preventing aerodynamic load imbalance while maintaining individual control capability during normal operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent merges the individual pitch control capability with synchronized feathering by combining two operations: first matching all blade pitch angles to a reference angle, then moving them collectively to the feathering position. This combination resolves the contradiction by ensuring blades move together during halting while maintaining individual control during operation.

Inventive Principle:

Principle #5Merging (Combining)

2Object-affected harmful factors

If pitch angles are matched before feathering, then aerodynamic load is reduced, but control complexity increases

Engineering Contradiction:

Improveaerodynamic loadVSAvoidcontrol complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies local quality by selecting one specific blade as a reference blade and using its pitch angle as the target for matching other blades. This approach simplifies the control complexity by establishing a clear reference point rather than requiring complex multi-variable coordination, while still achieving aerodynamic load reduction through pitch angle matching.

Inventive Principle:

Principle #3Local quality

3Productivity

If representative blade is identified and used for matching, then matching efficiency is improved, but time to reach feathering position increases

Engineering Contradiction:

Improvematching efficiencyVSAvoidtime to feathering position

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent applies partial action by having non-representative blades move to match the representative blade's pitch angle rather than all blades moving simultaneously to the feathering position. This partial matching approach improves efficiency by reducing the total adjustment required, while the representative blade continues moving to feathering, optimizing the overall time to reach the feathering position.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentEP2290232B1Windmill pitch angle controller and method for controlling windmill pitch angle

Publication Date: 2015.08.05 MHI VESTAS OFFSHORE WIND AS

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AI summary

The object is to reduce aerodynamic load when a wind turbine is halted. When a wind turbine halt command is input, pitch angles of wind turbine blades 5-1, 5-2, and 5-3 are matched, and then the pitch angles of the wind turbine blades 5-1, 5-2, and 5-3 are moved to a feathering position.