传统基于二阶广义积分器的锁相环(phase locked loop，PLL)尽管能应对三相不平衡或谐波情况下锁相问题，但是二阶广义积分器的正交发生器难以完全滤除所含谐波。针对三相不平衡和电网谐波污染时锁相困难的问题，提出了一种快速信号同步方案。首先，双二阶广义积分器(double second-order generalized integrator，DSOGI)可以实现正交信号的产生，滤除高次谐波，从而得到可能含有低次谐波的正序分量信号，保证三相不平衡时的精确锁相。其次，在dq同步旋转坐标系中，采用延迟信号消除(delay signal cancellation，DSC)方法滤除低偶数谐波，从而避免了采用低通滤波器(low-pass filter，LPF)时动态响应差的问题。最后，通过PI调节控制q轴分量为0，实现同步信号的快速提取。在Matlab/Simulink环境下的仿真结果验证了所提出的快速相位同步方案在电网不平衡和存在谐波污染的情况下能够实现快速锁相。

Although the traditional phase locked loop (PLL) based on double second-order generalized integrator (DSOGI) can finish the phase-lock in the case of three-phase imbalance or harmonics, the quadrature generator of the second-order generalized integrator is difficult to completely filter out all the harmonics. Aiming at the difficulty of phase lock when three-phase imbalance and grid harmonic pollution, this paper proposed a fast phase synchronization scheme. Firstly, the DSOGI can achieve quadrature signal generation, and filter out high-order harmonics, so that it can obtain the positive-sequence component which may contain low-order harmonics, and ensure accurate phase lock when the three-phase unbalance. In the dq synchronous rotation coordinate system, the delay signal cancellation (DSC) scheme was used to filter out the lower even harmonics, thereby avoiding the problem of poor dynamic response when applying low-pass filter(LPF). Finally, the q-axis component was controlled to 0 by PI regulation to realize the fast extraction of synchronous signal. The simulation results built in Matlab/Simulink verified that the proposed fast synchronous phase scheme can quickly phase lock when the power grid is unbalanced and exists harmonic pollution.