Abstract: Aiming at the problem that the traditional frequency-locked loop cannot reject the DC component of grid voltage,a frequencylocked loop structure based on DC component rejection loop is proposed. In order to improve the dynamic performance of the frequencylocked loop during startup stage and phase angle jump condition,the traditional frequency-locked loop structure is improved to reduce the gain of the frequency estimator loop,achieving fast and smooth phase angle tracking. Finally,a soft-start up single-phase frequencylocked loop which can reject DC component of grid voltage is proposed. Simulation analysis and experimental results show that the proposed structure has good steady-state and dynamic characteristics.