A method for accurately locking the frequency and phase of the positive sequence voltage of the fundamental wave is proposed in order to eliminate the influence of unbalanced grid environment, such as the unbalanced three-phase voltage, frequency mutation, phase mutation and injection harmonics, on the traditional phase locking method. The basic structure of the phase locked loop (αβ-PLL) of the stationary coordinate system is introduced, and the basic principle of the work of the phase locked loop in the static coordinate system is analyzed. Based on this, the positive and negative first-order complex filter is introduced which has a quality of selective, by improving the filter structure and designing its parameters reasonably, the positive-sequence fundamental voltage is detected accurately under the αβ coordinate system. The simulation result shows that, this method can make the frequency and phase of positive-sequence fundamental voltage be locked faster and more accurately.%为了消除因三相电压不对称、频率突变、相位突变、注入谐波等不平衡电网环境对传统锁相方法的影响,提出一种准确锁定基波正序电压频率以及相位的方法.介绍静止坐标系锁相环(αβ-PLL)的基本结构,分析静止坐标系锁相环工作的基本原理.基于此,引入具有极性选择性的正、负序一阶复数滤波器,通过改进滤波结构、合理选择其参数,在αβ 坐标系下实现了正序基波电压的准确提取.仿真结果表明,该方法能更快速准确的检测基波正序电压的幅值、频率及相位.
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