Wind Turbine Pitch Angle Error Detection Logic

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Solution Overview

Problem

Existing methods for operating wind energy installations with individual pitch devices struggle to detect errors in blade pitch regulation reliably and early, leading to potential malfunctions and mechanical stresses.

Innovation Solution

A method that measures actual blade pitch angles, calculates difference values, and accumulates logical link results to compare with threshold values, triggering an error signal when exceeded, while weighting large differences more heavily and allowing for decay of accumulated values over time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If individual pitch devices are used for each rotor blade, then the ability to detect and respond to blade-specific issues is improved, but the complexity of the control system and difficulty of detecting regulation errors increase

Engineering Contradiction:
Improveerror detection capabilityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the monitoring of multiple individual pitch devices into a unified control concept. Instead of treating each pitch device independently, the system evaluates all pitch angle actual values together, calculates difference values between blades, and accumulates logical link results across multiple time steps. This merging approach simplifies the overall control architecture while maintaining individual blade monitoring capability, resolving the contradiction between improved reliability and reduced system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system implements continuous feedback by repeatedly measuring actual pitch angles, calculating difference values, evaluating logical links, and accumulating results over time. The error detection is based on feedback from the accumulated values that exceed thresholds, creating a closed-loop monitoring system. This feedback mechanism enables reliable error detection without requiring complex additional hardware, as the existing pitch angle measurements are reused in a feedback-based evaluation cycle.

Inventive Principle:
Principle #23Feedback

2Loss of time

If difference values between blade pitch angles are accumulated over time, then early error detection is improved, but the computational requirements and processing complexity increase

Engineering Contradiction:
Improveerror detection timeVSAvoidprocessing complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The system performs preliminary actions by continuously accumulating logical link results from difference value evaluations before actual errors manifest into critical failures. The accumulation process begins immediately upon system operation, building up evidence of potential issues over time. This preliminary monitoring allows errors to be detected at their incipient stages, reducing the time loss before detection without requiring complex real-time analysis, as the accumulation happens in discrete time steps.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies partial action by focusing the accumulation process only on the essential logical link results related to pitch angle differences, rather than monitoring all possible operational parameters. The system selectively accumulates only the relevant difference value evaluations that contribute to error detection, avoiding unnecessary computational overhead. This partial monitoring approach achieves early error detection with moderate processing requirements, balancing detection speed and computational complexity.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If thresholds are set for accumulated values to trigger error signals, then operational safety is improved, but the risk of false alarms or missed detections increases

Engineering Contradiction:
Improveoperational safetyVSAvoiderror detection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The system employs parameter changes by using multiple threshold levels or adjustable threshold values that can be optimized based on operational conditions. The threshold for triggering error signals is set based on the accumulated logical link results, allowing the detection criteria to adapt to different operating scenarios. This parameter-based approach improves operational safety by providing clear decision criteria while maintaining detection accuracy through proper threshold selection, avoiding both false alarms and missed detections.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2915998B1Method for operating a wind turbine
Publication Date: 2018.02.28 NORDEX ENERGY
  • EP2915998B1 patent drawingFigure 1

AI summary

A method for operating a wind turbine with at least two rotor blades whose pitch angle is adjustable, characterized by: - ​​measuring an actual value of the pitch angle for each of the rotor blades, - generating at least one difference value by subtracting two measured actual values ​​of the pitch angles from each other, - generating at least one result of a logic operation by performing logical operations on at least one of the difference values, - generating an accumulated value by accumulating the at least one result of the logic operation, and - comparing the accumulated value with a predetermined threshold value, and - triggering an error signal if the accumulated value exceeds the predetermined threshold value.