Wind Turbine Generator Control for Grid Frequency Stability

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Solution Overview

Problem

Existing wind turbine generator control methods fail to maintain grid stability by only adjusting power output when frequency rises, neglecting potential frequency drops, which can lead to unstable utility grids.

Innovation Solution

A control method for wind turbine generators that decreases power output when the grid frequency exceeds a predetermined level and the rotational speed is below a certain threshold, and increases power output when the rotational speed exceeds this threshold to prevent over-speed, using a control device to manage the power output and rotational speed in response to grid frequency fluctuations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If power output is controlled only when frequency rises, then frequency stabilization is partially achieved, but grid stability cannot be maintained when frequency drops

Engineering Contradiction:
Improvegrid stabilityVSAvoidresponse to frequency fluctuations
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The control method dynamically adjusts power output based on real-time frequency conditions, switching between different control strategies: when frequency rises above rated frequency, power output is decreased; when frequency drops below rated frequency, power output is increased. This dynamic adaptation ensures comprehensive grid stability support across all frequency fluctuation scenarios.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the control parameter (power output) in response to frequency parameter variations. By monitoring frequency deviations from the rated frequency and adjusting power output accordingly, the system adapts to different grid conditions, achieving both frequency rise and drop stabilization.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If power output is decreased when frequency rises, then frequency stabilization is achieved, but generator rotational speed may increase causing over-speed risk

Engineering Contradiction:
Improvefrequency stabilizationVSAvoidgenerator rotational speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The control system implements feedback by continuously monitoring both frequency and rotational speed, and adjusting power output based on the combined state of these parameters. When frequency rises and rotational speed is below the second threshold, power output is decreased to stabilize frequency. When rotational speed approaches the second threshold, the control adjusts to prevent over-speed while maintaining frequency stability.

Inventive Principle:
Principle #23Feedback

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 approach stabilizes the utility grid by adjusting power output in response to both rising and falling frequencies, ensuring grid stability and preventing generator over-speed.

Implementation Method 1

a generator that is driven by rotation of the rotor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a rotor that rotates by wind power

Methodology Applied
Scientific EffectWind power: Wind Power

Data Source

PatentEP2463519B2Wind turbine generator, control method for wind turbine generator, wind turbine generator system, and control method for wind turbine generator system
Publication Date: 2021.10.27 MITSUBISHI HEAVY IND LTD
  • EP2463519B2 patent drawingFigure 1
  • EP2463519B2 patent drawingFigure 2
  • EP2463519B2 patent drawingFigure 3

AI summary

It is an object to stabilize utility grid even when an unexpected fluctuation in the frequency of the utility grid occurs. A wind turbine generator (1) includes a rotor (7) that rotates by wind power, a generator (5) that is driven by rotation of the rotor (7), and a control device (20) that controls a power output of the generator (5) to increase while a rotational speed of the generator (5) decreases when a frequency of a utility grid (13) becomes smaller than or equal to a predetermined rated frequency and when the rotational speed of the generator (5) is greater than or equal to a first predetermined value. In this way, even when the frequency of the utility grid (13) fluctuates, the frequency fluctuation can be suppressed, and the utility grid (13) can be stabilized.