Decoupled control of doubly-fed-induction generator under unbalanced grid voltage with modified reference generation

In this paper, the performance of a doubly-fed induction generator subjected to unbalanced grid voltage is presented. Instead of using double vector control and decomposing all the unbalanced vectors to positive, negative and zero sequence components the present scheme involves PI controller based stator flux oriented vector control. The power reference generation is based on the measured active power and estimated torque in order to reduce the torque and active power oscillations using Rotor Side Converter (RSC). The Grid Side Converter (GSC) is used to reduce the dc voltage oscillations and to maintain sinusoidal current exchange with the grid. Numerical simulations are carried out in PSCAD/EMTDC for the laboratory 3-hp DFIG test set up.