Modular Control System for Doubly-Fed Wind Turbines
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Solution Overview
Problem
Wind energy plants with doubly-fed asynchronous machines face challenges in adapting to varying grid fault ride through (FRT) requirements, leading to delays and increased costs due to the need for frequent redesign and testing of control systems.
Innovation Solution
A modular control system for wind energy plants with doubly-fed asynchronous machines, utilizing a direct current link and control modules that adjust torque, active power, and reactive current settings based on pre-selectable parameters to prevent disconnection from the grid until voltage falls below a predetermined voltage-time characteristic curve, allowing easy adaptation to different FRT requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the control system is redesigned to comply with new FRT requirements, then compliance with grid codes is improved, but development time and costs increase
Solution Approach 1:
The control system is segmented into a modular architecture where the command variable generation for fault conditions is separated from the converter control structure. This allows the command variable functions to be independently adapted to different FRT requirements without redesigning the entire control system, thereby reducing development and testing time while maintaining compliance with grid codes.
Solution Approach 2:
The control system is designed with universal converter control structures that can handle multiple FRT scenarios. By making the command variable functions adaptable through parameter selection rather than structural changes, the same control hardware and basic control logic can serve multiple grid code requirements, reducing development time and costs.
2Adaptability or versatility
If the control structure is redesigned for different FRT requirements, then adaptability to grid codes is improved, but device complexity increases
Solution Approach 1:
The control system is divided into fixed control structures and adaptable command variable functions. This segmentation allows adaptability to be achieved through parameter selection in the command variable generation rather than through structural changes, thereby maintaining simple device architecture while improving adaptability to different FRT requirements.
Solution Approach 2:
Adaptability to different FRT requirements is achieved by changing parameters within the command variable functions rather than modifying the control structure. This allows the same control device to adapt to various grid codes by selecting appropriate parameters, avoiding increases in device complexity while maintaining high adaptability.
Data Source
AI summary
A wind energy plant and method for operating it, the plant having a doubly-fed asynchronous machine, a grid-sided converter and a generator-sided converter both being controlled by a control means. In case of a grid fault the converters are controlled by at least one control module which (i) controls the torque and/or the active power and (ii) controls the reactive current and/or the reactive power.