中文摘要：

传统的d-q锁相技术在电网电压不平衡、电压谐波畸变情况下无法获得精确的电网频率／相位信息，因而无法获得很好的并网控制性能。此处对传统的d-q锁相原理和电网不对称情况下锁相失效的原因进行了分析．在此基础上，对传统的d-q锁相进行了改进，得到了新的锁相方法，即采用多个全通滤波器（APF）进行相序分离的锁相方法。实验验证了新的锁相方法的正确性和可行性。

英文摘要：

Under ideal grid conditions, the synchronous reference frame phase lock enables fast and accurate phase/ frequency detection.However,unbalanced and distorted grid conditions highly degrade its perforrnance.A detail analysis is made on the principle of traditional d-q phase lock.Based on the analysis, an improvement is made and a new phase lock technology is gotten.At last, the experimental results are presented to support the new theoretical analysis.