A Novel Scheme of Computer Application for Extracting Grid Fundamental Positive Sequence Voltage Vector under Unbalance and Distortion Grid Condition

摘要

This paper proposed a novel scheme for grid fundamental positive sequence voltage detection. By means of transferring three-phase voltage to α, β two-phase reference frame and converting with two simple mathematical transfermations, it is able to obtain grid fundamental positive sequence voltage through eliminating negative sequence and harmonic component of grid voltage in α, β reference frame. Based on the grid fundamental positive sequence voltage, a software phase locked loop, which is used for idea grid, is applied to track grid voltage synchronization phase rapidly and correctly. Experimental and simulation results validate that the proposed method has features of high precision and fast dynamic response, which provides the basis of the control of three-phase PWM rectifier under nonideal even fault grid.