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Optimal FRT Crowbarless solution for DFIG topology up to 3.5 MW

15/05/2016
Optimal FRT Crowbarless solution for DFIG topology up to 3.5 MW
Media: AWEA 2016.
Date: May 2016 (23/05/2016)
Type: Conference presentation.
Author: Aritz Lorea

Summary: The Doubly Fed Induction Generator (DFIG) topology is proven as the most efficient and cost-competitive topology for wind turbines rated up to 3.5 MW. However, continuous evolution of the grid codes jeopardizes the use of this type of conversion system, due to its high sensitivity to FRT events, in which high voltages and currents appear in the rotor side of the generator. Most widely used solutions to fulfill the FRT requirements consist in actively controlled crowbar-base systems, which have been identified to have limitations in fulfilling the most demanding grid codes.

This paper presents a FRT crowbarless solution, based on a chopper system, which allows for a cost-optimal power converter adapted for each grid code and generator characteristics, due to its modularity. A deep analysis of key components is developed, including IGBT CFD and generator non-linear response, and a new control technique is implemented.

Finally, experimental results in a 3 MW Wind Turbine with a rotor peak current up to 12 kA prove the validity of the modular solution for grid codes in markets with high wind energy integration and for a range of type generators. The solution achieves a current feed-in time of less than 50ms for 2-ph and 3-ph voltage dips.


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