Wind Turbine Rotor Braking via Segmented Torque Control

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Solution Overview

Problem

Wind turbines face operational safety risks and increased load conditions during secondary operating modes outside of power-optimized normal operation, particularly due to malfunctions that can lead to rotor blade pitch angle errors and excessive rotational speeds.

Innovation Solution

Implementing a method that includes adjustable rotor blades and a safety system to initiate braking processes when rotational speed, acceleration, or pitch rate limits are exceeded, with adjustable parameter limits and monitoring to prevent malfunctions, especially in reduced-speed or power modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the rotor is stopped by applying a braking torque to the main rotor shaft during a grid failure, then the rotor can be quickly brought to a standstill, but high stopping torques cause excessive mechanical stress on the drivetrain components

Engineering Contradiction:

Improverotor stopping speedVSAvoidmechanical stress on drivetrain

Core Design Contradiction:

SpeedVSStress or pressure

Solution Approach 1:

The braking process is divided into two distinct phases: a first braking phase with limited braking torque to reduce speed to a threshold value, and a second braking phase with higher braking torque to bring the rotor to complete standstill. This segmentation prevents excessive mechanical stress during the initial high-speed braking while still achieving rapid overall stopping.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The braking torque is dynamically adjusted based on the rotor speed. The control system monitors the rotor speed and automatically transitions between the first braking phase (with lower torque) and the second braking phase (with higher torque) to optimize the stopping process and protect drivetrain components from excessive stress.

Inventive Principle:

Principle #15Dynamics

2Stress or pressure

If a conventional braking system with limited braking torque is used, then mechanical stress on the drivetrain is reduced, but the rotor cannot be quickly brought to a standstill

Engineering Contradiction:

Improvemechanical stress on drivetrainVSAvoidrotor stopping time

Core Design Contradiction:

Stress or pressureVSLoss of time

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #15Dynamics

3Loss of time

If high braking torque is applied immediately during grid failure, then the rotor stops quickly, but the risk of damaging drivetrain components increases

Engineering Contradiction:

Improverotor stopping timeVSAvoiddrivetrain component reliability

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #15Dynamics

4Reliability

If the wind turbine is completely shut down during grid failure, then the drivetrain is protected from damage, but the wind energy available for grid restoration cannot be utilized

Engineering Contradiction:

Improvedrivetrain protectionVSAvoidenergy availability for grid restoration

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control system continuously monitors rotor speed and grid status, using feedback to determine when to apply braking torque and when to allow the rotor to accelerate again. This feedback mechanism enables the wind turbine to quickly respond to grid failures and restoration signals, making the available wind energy accessible when needed for grid restoration.

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP2846037B1Method for operating a wind turbine and a wind turbine

Publication Date: 2022.09.14 SIEMENS GAMESA RENEWABLE ENERGY SERVICE GMBH

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AI summary

The invention relates to a method for operating a wind turbine (10) with a rotor (12) having at least one angle-adjustable rotor blade (14), wherein the wind turbine (10) is operated in a first operating mode (71) and/or a second operating mode (75), wherein in the first operating mode (71) a braking process of the rotor (12) is initiated when the rotational speed of the rotor (12) exceeds a first speed limit. The invention further relates to a method for operating a wind turbine (10) with a rotor (12) having at least one angle-adjustable rotor blade (14), wherein an operating parameter is monitored and a braking process of the rotor (12) is initiated when an operating parameter limit is reached.The method according to the invention is characterized in that, in the second operating mode, a braking process of the rotor (12) is initiated when the rotational speed of the rotor (12) is greater than a second rotational speed limit, wherein the second rotational speed limit is less than the first rotational speed limit, and/or wherein, in the first and/or second operating mode, a braking process of the rotor (12) is initiated when a rotor acceleration prevails that is greater than a rotor acceleration limit. The wind turbine (10) according to the invention is characterized in that the operating parameter limit in the first operating mode differs from the operating parameter limit in the second operating mode and/or that the operating parameter limit is variable depending on at least one operating parameter.