Wind Turbine Generator Torque Control During Voltage Dip Recovery

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Solution Overview

Problem

Wind turbines face challenges in complying with grid codes that require them to ride through low voltage or zero voltage events without disconnecting from the grid, as existing methods can lead to torsional oscillations and potential damage to drive train components due to improper torque management during recovery from voltage dips.

Innovation Solution

A method for operating a wind turbine that involves detecting the end of a voltage dip, determining the rotor's acceleration, and increasing the generator torque according to a selected torque profile from a plurality of predetermined profiles, which helps in managing torque levels and reducing peaks in generator speed and electrical power, thereby preventing damage to drive train components and ensuring timely recovery of power production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the wind turbine rapidly reduces power supplied to the grid by reducing generator torque during a voltage dip, then compliance with grid codes is improved, but torsional oscillations in drive train elements increase

Engineering Contradiction:

Improvecompliance with grid codesVSAvoidtorsional oscillations

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamic torque control during voltage dips by continuously adjusting generator torque based on real-time measurements of drive train torque and generator speed. The controller modifies torque reduction strategy dynamically rather than applying fixed torque reduction, allowing adaptation to changing grid conditions and drive train states to minimize torsional oscillations while maintaining LVRT compliance.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system employs feedback control by measuring actual drive train torque and generator speed during the voltage dip event, then using these measurements to adjust generator torque in real-time. This closed-loop control enables the system to respond to actual drive train conditions rather than following predetermined torque profiles, thereby reducing harmful torsional oscillations while maintaining grid code compliance.

Inventive Principle:

Principle #23Feedback

2Strength

If the wind turbine waits before resuming normal power generation after a voltage dip, then drive train components are protected from damage, but productivity is reduced

Engineering Contradiction:

Improvedrive train component integrityVSAvoidpower generation recovery time

Core Design Contradiction:

StrengthVSProductivity

Solution Approach 1:

The patent applies preliminary action by detecting the end of the voltage dip event and immediately initiating controlled torque increase procedures before actual damage can occur. The system proactively manages the torque recovery process by gradually increasing generator torque while continuously monitoring drive train conditions, allowing rapid yet safe resumption of power generation without waiting for extended protection periods.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses dynamic torque adjustment during the recovery phase, continuously adapting generator torque based on real-time drive train torque measurements and generator speed. This dynamic control enables the system to resume power generation as quickly as safety conditions permit, optimizing the balance between component protection and productivity recovery rather than using fixed waiting periods.

Inventive Principle:

Principle #15Dynamics

3Productivity

If the wind turbine increases generator torque quickly after a voltage dip to resume power production, then productivity is improved, but torque peaks that could damage drive train components occur

Engineering Contradiction:

Improvepower production recovery speedVSAvoiddrive train component safety

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The patent implements dynamic torque control during the recovery phase by continuously adjusting generator torque based on real-time measurements of drive train torque and generator speed. The controller modulates torque increase rate dynamically rather than applying fixed ramp rates, allowing the system to recover power production as quickly as safety conditions permit while preventing harmful torque peaks that could damage drive train components.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system employs feedback control during torque recovery by measuring actual drive train torque and generator speed, then using these measurements to adjust the torque increase rate in real-time. This closed-loop control enables the system to identify safe operating boundaries dynamically and adjust torque application accordingly, maximizing power production recovery speed while maintaining drive train component safety.

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP3772172B1Verfahren zum betrieb einer windkraftanlage und einer windkraftanlage mit generator im falle eines spannungseinbruchs

Publication Date: 2022.08.31 GENERAL ELECTRIC CO

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AI summary

A method of operating a wind turbine comprising a generator in the event of a voltage dip is disclosed. The method comprises detecting an end of the voltage dip, determining an acceleration of a rotor of the generator, and increasing a torque of the generator when the end of the voltage dip is detected according to a selected torque profile. The selected torque profile is selected from a plurality predetermined torque profiles, wherein the predetermined torque profiles describe torque as a function of time. The selected torque profile is selected based on the determined acceleration of the rotor of the generator. Also provided are wind turbines configured for such methods.