考虑到不平衡电网条件下，传统锁相环的局限性，这里比较了几种基于正负序分离的锁相环着重基于陷波器的提取方式-Taking into account the unbalanced grid conditions, the limitations of the traditional PLL, where positive and negative sequence based on comparison of several separat

pll-sogi which is used to cap the phase of U