Grid-Forming Wind Turbine Control for Power Oscillation Damping

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Solution Overview

Problem

The implementation of a DC link controller in grid forming wind turbines can cancel out or significantly reduce the inertial effect and damping power effect, leading to inadequate damping of power oscillations in the power grid.

Innovation Solution

A method for controlling the power output of a grid forming wind turbine by calculating damping and inertia power references, generating a feedforward power reference that includes these, and controlling the machine side converter based on this reference to ensure effective damping and inertia response.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a DC link controller is implemented in the grid side converter control to maintain voltage at a reference level, then voltage stability is improved, but the inertial effect and damping power effect are cancelled out or significantly reduced

Engineering Contradiction:

Improvevoltage stabilityVSAvoiddamping of power oscillations

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The power reference is segmented into multiple components: a base power reference from the DC link controller, and additional damping power and inertia power components. These segmented components are summed to create a total power reference that simultaneously achieves voltage stability and power oscillation damping.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention merges the DC link controller's voltage stabilization function with the damping power and inertia power functions. By combining these control objectives in the power reference calculation, the system achieves both voltage stability and effective damping of power oscillations without mutual interference.

Inventive Principle:

Principle #5Merging (Combining)

2Stability of the object's composition

If the DC link controller seeks to keep voltage at a certain reference level, then voltage control is improved, but the desired damping of power oscillations is not obtained

Engineering Contradiction:

Improvevoltage controlVSAvoidpower oscillations

Core Design Contradiction:

Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The damping power and inertia power are calculated in advance based on grid frequency and its derivative, and are added to the base power reference before being sent to the converter. This preliminary anti-action counteracts power oscillations before they can develop, while the DC link controller maintains voltage control independently.

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS12492678B1Method for controlling a power output of a grid forming wind turbine

Publication Date: 2025.12.09 VESTAS WIND SYSTEMS AS

AI summary

A method for controlling a power output of a grid forming wind turbine (1) in order to dampen power oscillations between a power grid (13) to which the wind turbine (1) is connected and the wind turbine (1) is disclosed. A damping power reference, PD, depending on a grid frequency of the power grid (13) and/or on a virtual rotor speed is calculated, with the purpose of dampening oscillations in the power output of the grid side converter (11). A power output of the grid side converter (11) is controlled, in accordance with a grid side power reference, Pref, and taking the damping power reference, PD, into account. A feedforward power reference for the machine side converter (10) is generated, the feedforward power reference including the damping power reference, PD, and an inertia power reference, PI, proportional to the time derivative of the grid frequency, and a power output of the machine side converter (10) is controlled at least partly based on the feedforward power reference.