The basic requirement for implementing high-performance grid-connected inverter control is to quickly and accurately obtain the sequence components(i. e.

positive

negative and zero sequence components)of the three-phase unbalanced grid voltage. This paper proposes a practical extraction method of sequence components

and it can significantly improve the extraction speed of voltage sequence components in unbalanced grid. The method first uses the virtual quadrature signal construction method and the single-phase locked operation to obtain the virtual three-phase voltage phasor. Next

the symmetrical component method and the single-phase-locked inverse operation can be used to quickly obtain the amplitude and real-time phase of the sequence component. The method only needs the grid voltage and its virtual orthogonal signal to calculate the amplitude and phase of the voltage sequence component

and the method does not require parameter design and debugging process. Meanwhile

its calculation accuracy can meet engineering requirements. The correctness of the method is verified by MATLAB/Simulink real-time simulation platform.