A Fast Extraction of Positive Sequence Components with Noise Immunity in Unbalanced Conditions

Fast and accurate acquisition of voltage components are the basic requirement for grid-connected inverters to realize various control under unbalanced grids. In view of this situation, a delay sampling period filter (DSPF) algorithm, which rapidly separates each voltage component by delaying two sampling periods of voltage components under dq frame, is proposed. Besides, in view of the noise interference in the grid voltage, a delay operation period filter (DOPF) algorithm is proposed to scale the operation period and limit the noise level to an acceptable range. Finally, the corresponding model is built in MATLAB and physics experiment platform to verify the feasibility and priority of this method.