Wind Turbine Converter Control for Grid Stability

Solution Overview

Problem

Conventional wind turbines face inefficiencies and potential converter overload when trying to balance energy demand and supply with the utility grid, leading to reduced efficiency and potential damage, as they increase power output temporarily to stabilize grid frequency, which can result in rotor slowdown and decreased production.

Innovation Solution

A method and system for controlling electric devices within wind turbines that receive state signals from the utility grid to adjust operations, such as reducing internal consumption or increasing power transfer, without overloading converters, by using a controller to manage power flow and maintain grid stability without overloading the converter during transient situations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the power output of the converter is increased temporarily to stabilize grid frequency, then grid stability is improved, but the rotor rotational speed decreases and production efficiency is reduced

Engineering Contradiction:

Improvegrid stabilityVSAvoidproduction efficiency

Core Design Contradiction:

Stability of the object's compositionVSProductivity

Solution Approach 1:

The control system performs preliminary assessment of grid frequency conditions and proactively adjusts converter output before significant frequency deviations occur. By monitoring grid state signals and predicting frequency trends, the system prepares appropriate power adjustment actions in advance, preventing the need for large temporary output increases that would slow the rotor and reduce production efficiency.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously receives feedback from grid state signals (frequency, voltage, power flow) and dynamically adjusts converter output accordingly. This closed-loop control ensures that power output is increased only when and to the extent necessary for grid stability, avoiding unnecessary rotor slowdown and maintaining optimal production efficiency while still providing grid support when needed.

Inventive Principle:

Principle #23Feedback

2Stability of the object's composition

If the converter output is increased to balance energy demand and supply, then grid frequency is restored, but the converter and turbine drive train are overloaded

Engineering Contradiction:

Improvegrid frequency stabilityVSAvoidconverter reliability

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

Instead of increasing converter output to full capacity during frequency events, the control system applies partial action by adjusting output only to the degree necessary to restore grid frequency. The system calculates the minimum required power increase based on grid state signals and applies only that amount, avoiding excessive loading of the converter and turbine drive train while still achieving grid frequency stabilization.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The control system performs preliminary assessment of grid frequency conditions and proactively adjusts converter output before significant frequency deviations occur. By monitoring grid state signals and predicting frequency trends, the system prepares appropriate power adjustment actions in advance, preventing the need for large temporary output increases that would slow the rotor and reduce production efficiency.

Inventive Principle:

Principle #10Preliminary action

3Stability of the object's composition

If the wind turbine increases power output temporarily during low frequency events, then grid frequency is stabilized, but the turbine drive train experiences increased load and potential damage

Engineering Contradiction:

Improveutility grid stabilityVSAvoidturbine drive train integrity

Core Design Contradiction:

Stability of the object's compositionVSStrength

Solution Approach 1:

Instead of increasing converter output to full capacity during frequency events, the control system applies partial action by adjusting output only to the degree necessary to restore grid frequency. The system calculates the minimum required power increase based on grid state signals and applies only that amount, avoiding excessive loading of the converter and turbine drive train while still achieving grid frequency stabilization.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The control system uses the natural kinetic energy already present in the rotating rotor mass to support grid frequency without imposing additional mechanical stress on the drive train. By controlling the converter to allow temporary rotor acceleration rather than forcing mechanical power increases, the system converts the rotor's kinetic energy into useful grid support, avoiding drive train overload while stabilizing grid frequency.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentEP2458205B1Method and system for controlling an electric device of a wind turbine

Publication Date: 2016.10.19 SIEMENS AG

AI summary

It is described a method for controlling an electric device (117, 121, 123, 125, 127, 129) of a wind turbine (100), the method comprising: receiving a state signal (f) of a utility grid (115) electrically connected to the electric device; and controlling an operation of the electric device based on the state signal. Further, a system for controlling an electric device of a wind turbine and a wind turbine is provided.