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Fault Ride Through Techniques of DFIG-based Wind Energy Systems. Presenter: Lingling Fan, Co-authors: Chanxia Zhu, Minqiang Hu (Southeast University , Nanjing China) Assistant Professor Electrical Engineering University of South Florida Tampa, FL 33620 USA. Outline. Objectives
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Fault Ride Through Techniques of DFIG-based Wind Energy Systems Presenter: Lingling Fan, Co-authors: Chanxia Zhu, MinqiangHu (Southeast University, Nanjing China) Assistant Professor Electrical Engineering University of South Florida Tampa, FL 33620 USA
Outline • Objectives • Analysis of DFIG behavior during faults • Single phase fault ride through • Three-phase fault ride through • Simulation results • Conclusion
Objective • Design control schemes to help DFIG ride through faults • Faults: Balanced (symmetrical) or unbalanced (unsymmetrical) • In literature, ride through balanced faults and unbalanced faults are treated separately • A control scheme for all
fm Doubly Fed Induction Generator Ps RSC AC/DC GSC DC/AC Pr = sPs
DFIG converter control loops GSC DC/AC RSC DC/AC
Analysis of DFIG behavior during unbalanced faults Unbalanced stator currents Positive sequence (fe) Negative sequence (-fe) Zero sequence Rotor currents Ir: fe-fm=sfe Ir: -fe-fm=-(2-s)fe s: slip = 1-fm/fe fm: electric frequency corresponding to rotating speed. fe: nominal frequency 60 Hz (stator) – 50 Hz (rotating speed) = 10 Hz -60 Hz (stator) – 50 Hz (rotating speed) = -110 Hz
Reference frames Pos. Neg. Sequences and DC can be separated by a dc filter!
Fault ride through schemes- modify RSC current control loops
Conclusion • Proportional Resonant control is proposed for RSC to mitigate rotor current high frequency components and surge. • Simulation results demonstrate the effectiveness. • A major contribution: both unbalanced and balanced faults are considered.