Virtual Synchronous Machine Angular Stability Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing methods for emulating synchronous machine behavior in converters do not effectively handle network errors, leading to potential angular instability and loss of stability in electrical supply networks.

Innovation Solution

A control module for power converters, comprising a power module to calculate power changes and a correction module to set power set points, which identifies angular instability and adjusts power output to maintain stability by multiplying power and power angle changes to form a coefficient indicative of stability, and only intervenes when a threshold is exceeded.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If converters operate like synchronous machines to stabilize the electrical supply network, then angular stability is improved, but vulnerability to network errors increases

Engineering Contradiction:

Improveangular stabilityVSAvoidrobustness against network errors

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The control module continuously monitors the power change dP/dt and compares it against a threshold value. When the power change exceeds the threshold, indicating a network error, the system automatically adjusts the power set point to prevent angular instability. This closed-loop feedback mechanism enables the virtual synchronous machine to detect and respond to network disturbances while maintaining stability.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The control module proactively identifies critical states by monitoring power changes before angular instability occurs. By detecting when dP/dt exceeds the threshold and adjusting the power set point in advance, the system prevents instability rather than reacting after it occurs. This preliminary action allows the converter to maintain stable operation even during network errors.

Inventive Principle:

Principle #10Preliminary action

2Stability of the object's composition

If the converter continuously adjusts power output to maintain stability, then angular stability is improved, but control complexity increases

Engineering Contradiction:

Improveangular stabilityVSAvoidcontrol complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The control module applies stability control selectively rather than continuously. It monitors the power change dP/dt and only intervenes when this parameter exceeds a predefined threshold, indicating a network error. This localized approach to control activation reduces the overall control complexity while maintaining angular stability when needed.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system changes its control behavior based on the parameter dP/dt (power change). When this parameter remains within normal limits, the converter operates with standard control. When dP/dt exceeds the threshold, the control module adjusts the power set point parameter to maintain stability. This parameter-based control strategy simplifies the overall control structure by using clear threshold-based decision logic.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11566601B2Device and method for angle stabilization of a virtual synchronous machine

Publication Date: 2023.01.31 WOBBEN PROPERTIES GMBH

AI summary

Provided is a control circuit of a converter, in particular a power converter of a wind power installation, configured to control the converter in such a way that the converter emulates a behavior of a synchronous machine. The control circuit includes a power module for calculating a power change depending on a detected power and a correction module for setting a power set point, in particular for the converter, depending on the calculated power change.