Improved the ride-through capability of wind power plants using doubly-fed induction generator under unbalanced voltage conditions

Abstract

This paper presents study results on the application aspect of the symmetrical components analysis method in order to improve the asymmetrical grid voltage fault ride-through capability of wind generator systems. When the grid voltage undergoes a fault the grid side converter needs to force the wave form of the grid currents similar to that of the basis positive sequence component of the grid current and to guarantees that the negative sequence has to be eliminated as much as possible. In order to do so, the current controller should be implemented on both the positive and negative rotational coordinates. Simutaneously, the rotor side current controller is stopped from working and the rotor windings of the generator are short circuited by a dissipative resistor bank to maintain the synchronization of the generator with the power supply. The simulation results in the Matlab - Simulink - Plecs environment show, with the application of the proposed stratergy, that the grid currents become more balanced under asymmentrical grid voltage fault.