Wind Turbine Generator Negative Sequence Current Regulator

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Solution Overview

Problem

Variable-speed wind turbine power generation systems face inefficiencies due to electrical imbalances in generator and converter currents, leading to reduced power transmission to the grid.

Innovation Solution

A negative sequence current regulator is employed to balance thread currents, using frequency-dependent D-axis and Q-axis negative sequence gains to manage currents across the generator and line converters, ensuring balanced three-phase currents and maximizing wind power transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If variable-speed operation is used to capture more wind energy, then power generation efficiency is improved, but electrical current imbalances occur leading to reduced power transmission

Engineering Contradiction:

Improvepower generation efficiencyVSAvoidpower transmission loss

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent employs a negative sequence current regulator that continuously monitors generator currents and dynamically adjusts converter thread currents to compensate for imbalances. This feedback mechanism detects current imbalances caused by variable-speed operation and actively corrects them, ensuring balanced three-phase currents are transmitted to the grid while maintaining variable-speed operation for maximum wind energy capture.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent dynamically changes operating parameters (converter thread currents) based on detected generator current imbalances. By adjusting the converter currents in response to varying wind conditions and generator speeds, the system maintains balanced power transmission across the full variable-speed operating range, resolving the contradiction between variable-speed efficiency and transmission balance.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If multiple converter threads are used to handle variable power, then adaptability is improved, but current imbalances between threads increase

Engineering Contradiction:

Improvepower handling adaptabilityVSAvoidcurrent balance stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The negative sequence current regulator monitors all converter thread currents and generator currents simultaneously, using feedback control to detect imbalances between parallel threads. When imbalances are detected, the regulator dynamically adjusts individual thread currents to restore balance, enabling the system to adapt to varying power conditions while maintaining stable, balanced three-phase current output to the grid.

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP2595308B1System for improved wind turbine generator performance

Publication Date: 2022.03.30 GENERAL ELECTRIC CO

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AI summary

A system 10 for improving wind turbine generator 24 performance is disclosed. In one aspect a rotary power generation system is provided, including: a rotary power generator 24 for generating variable-frequency alternating currents; a negative sequence current regulator 50 that determines and uses frequency-dependent D-axis and Q-axis negative sequence gains based on an electrical frequency of the rotary power generator 24; and a system 58 for controlling voltage components for balancing the variable-frequency alternating currents generated by the rotary power generator (24) based on the D-axis and Q-axis negative sequence gains.