讲述并网逆变器中全软件锁相环的设计与实现，，即检测基波正序分量的电网电压不平衡和扭曲的条件下。明确地,提出了一种积极的基于一种新的序列检测器双同步坐标系的解耦锁相环（双dq–PLL），完全消除了检测误差传统的同步参考框架（SRF–锁相环PLL）(and implementation of all software phase-locked loop in grid connected inverter is described, that is, detecting the positive and negative component of the fundamental wave under unbalanced grid voltage conditions. Explicitly, a positive decoupling phase locked loop (double DQ - PLL) based on a new sequence detector dual synchronous coordinate system (double DQ - PLL) is proposed, which completely eliminates the traditional synchronous reference frame (SRF - PLL PLL) for detection error.)