Power Converter Stabilizer for Grid Contingency Oscillations

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Solution Overview

Problem

Power converters in wind turbine generators experience system oscillations during recovery from grid contingency events, leading to instability in power output and grid stability issues.

Innovation Solution

A stabilizer system that generates command signals based on measured PLL errors to control reactive and real current outputs of the power converter, reducing oscillations by adjusting voltage and power regulator stabilization signals to stabilize the system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the power converter operates during grid contingency events to maintain LVRT/ZVRT capability, then grid stability is improved, but system oscillations occur during recovery leading to instability

Engineering Contradiction:

ImproveLVRT/ZVRT capabilityVSAvoidsystem stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The stabilizer system is activated in advance during grid contingency events before the LVRT/ZVRT sequence begins. By preemptively applying stabilization signals to dampen potential oscillations, the system prepares for the upcoming instability conditions, allowing the power converter to maintain LVRT/ZVRT capability without suffering from severe oscillations during recovery

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The stabilizer system continuously monitors system conditions and dynamically adjusts stabilization signals based on real-time feedback. This closed-loop control detects oscillations as they develop during LVRT/ZVRT operation and applies counteracting signals, enabling the system to maintain both grid stability and LVRT/ZVRT capability simultaneously

Inventive Principle:

Principle #23Feedback

2Productivity

If the power converter returns to steady-state operation quickly after a grid contingency event, then productivity is improved, but system oscillations cause instability

Engineering Contradiction:

Improverecovery speedVSAvoidpower output stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The stabilizer system dynamically adjusts its stabilization signals based on the changing system conditions during recovery. The control parameters are adapted in real-time to match the transition from contingency to steady-state operation, enabling faster recovery while maintaining stability through continuous optimization of control characteristics

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP2658112B1Methods and Systems for Controlling a Power Converter

Publication Date: 2020.08.26 GENERAL ELECTRIC CO

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AI summary

A stabilizer system (182) associated with a power converter controller (44) is described. The stabilizer system includes a regulator stabilizer (186) configured to receive a phase locked loop (PLL) error signal (190) and to generate a regulator stabilization signal (188) based at least partially on the PLL error signal. The stabilizer system also includes a regulator (184, 204) coupled to the regulator stabilizer and a converter interface controller (156). The regulator is configured to receive the regulator stabilization signal, generate a first command signal (192, 166), based at least partially on the regulator stabilization signal, that reduces system oscillations, and transmit the first command signal to the converter interface controller.