VSM Wind Turbine Damping Control via Line Side Converter Power
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Solution Overview
Problem
Conventional methods for damping mechanical oscillations in wind turbines configured as virtual synchronous machines (VSMs) are not effective, as they cannot utilize existing drive train damping methods, necessitating a new approach for controlling VSMs to manage these oscillations.
Innovation Solution
A method for damping mechanical oscillations in wind turbines involves obtaining a speed signal, determining a drive train damping power signal, calculating a virtual synchronous machine rotational speed and angle, and using the line side converter to generate active power variations based on these calculations, with optional bandwidth modification and amplitude adjustment to ensure stability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional drive train damping methods are used in VSM configured wind turbines, then existing damping control can be applied, but the method is not suitable for VSMs and cannot be utilized
Solution Approach 1:
The patent introduces a virtual synchronous machine model as an intermediary layer between the physical wind turbine drive train and the power converter control system. This virtual model enables conventional damping methods to be applied by creating a mathematical representation that bridges the gap between physical oscillations and electrical control, allowing VSMs to exhibit synchronous generator-like behavior while maintaining compatibility with existing damping techniques
Solution Approach 2:
The patent modifies control parameters by determining virtual synchronous machine rotational speed and angle based on power deviation, and using these to generate converter references. This parameter transformation allows the system to translate mechanical oscillation signals into appropriate electrical control signals that achieve damping effects in the VSM configuration, effectively adapting conventional methods to the new system architecture
2Reliability
If the line side converter generates active power variations based on virtual synchronous machine angle, then mechanical oscillations are dampened, but system complexity increases
Solution Approach 1:
The patent makes the line side converter multi-functional by using it not only for standard power conversion and grid synchronization but also for generating active power variations specifically for damping mechanical oscillations. By utilizing the existing line side converter for this additional damping function through virtual synchronous machine control, the patent avoids adding separate dedicated damping actuators, thereby reducing overall system complexity while achieving improved stability
Solution Approach 2:
The patent implements a feedback mechanism where the virtual synchronous machine angle and rotational speed are continuously determined based on power deviation from mechanical oscillations, and this feedback is used to adjust the converter reference for the line side converter. This closed-loop feedback control automatically adjusts power variations to counteract oscillations, providing stable damping control without requiring complex manual intervention or additional sensing infrastructure
Data Source
AI summary
The invention relates to a method for damping drive train oscillations of a VSM configured wind turbine. The method comprises determining a drive train damping power signal based on speed signal representing a generator speed, determining a power deviation based on a combination of a power reference for a desired power production, the drive train damping power-signal, a grid power supplied by the line side converter to the grid and a damping power, determining a virtual synchronous machine angle based on the power deviation so that the derivative of the virtual synchronous machine rotational speed is indicative of the power deviation, determining a converter reference for controlling the line side converter to generate the desired active power based on the virtual synchronous machine angle and a voltage reference for a voltage amplitude to be generated by the line side converter, and applying the converter reference to the line side converter.