Mehdi Samiei Sarkhanloo - Islamic Azad University, Ardabil, Iran
Mir Mohammad Mir Mousavi - Islamic Azad University, Tehran, Iran
Akbar Danandeh - Islamic Azad University, Tabriz, Iran

In this paper, a new wind farm topology is considered, where series connected fixed speed wind turbines (FSWTs) are installed with variable speed wind turbine (VSWT) driven bydoubly fed induction generators (DFIGs). Fixed speed wind generators (FSWGs) are largely dependent on reactive power, sothey require large reactive power when a short circuit fault occurs in the power system. Otherwise, they become unstable and have to be disconnected from the power system. A new directpower control (DPC) strategy based on discrete space vector modulation (DSVM) technique, is implemented to control DFIGbasedwind turbine system. DPC-DSVM strategy which has constant switching frequency and the simple structure withoutextra the current control loops, is applied to DFIG rotor side converter in order to decoupled control the stator powers. By DSVM technique, a more numbers of voltage space vector invarietal sizes can be synthesized with respect to those used in classic DPC techniques, more accurate selecting voltage vector,decreasing power and current ripples, and improving transient performance. Simulation results confirm that the proposedtopology with control strategies is a cost effective solution and simplified system design to minimize voltage fluctuation of bothfixed and variable speed WTGs as well as to improve the transient stability of the wind farm

Doubly fed induction generator, Direct power control, Discrete space vector modulation, Fixed speed wind turbine, Frequency converter/inverter