Fast on-line symmetrical components separation method for synchronization and control purposes in three phase distributed power generation systems.

This work introduces a fast symmetrical components separation method, in order to obtain instantly positive and negative phase sequence. Therefore, intrinsic delay presents in other sequence detection methods, like delayed signal cancellation, is removed. Accurate positive and negative phase-sequence components are obtained with the proposed method, tested by simulation under different grid voltage dips or unbalance condition. Experimental results show good performance in presence of a clean grid voltage waveforms. However, when grid voltages are distorted due to the harmonic content, the outputs of proposed system deliver a significant and undesirable amount of ripple. Therefore, an additional block to eliminate grid voltage harmonics is needed in order to take advantage of the proposed method.