改进型解耦自适应复数滤波器的锁相环研究

Study on improved crossing-decoupling frequency-adaptive complex filter PLL

为了消除因三相电压不对称、频率突变、相位突变和注入谐波等不平衡电网环境对传统锁相方法的影响,提出了一种准确锁定基波正序电压频率以及相位的方法。介绍了静止坐标系锁相环(αβ-PLL)的基本结构,分析了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地检测基波正序电压的幅值、频率及相位。

This paper proposes a method of three-phase voltage phase and frequency locked loop in order to reduce the influence of traditional PLL under distorted voltage conditions like voltage dip, frequency mutation, phase mutation, harmonics injected. This paper tells how αβ-PLL works under the conditions of ideal power grid. On this basis, this paper introduces the positive and negative first-order complex filter which has a quality of selectivity, by improving the filter structure and designing its parameters reasonably, positive-sequence fundamental voltage is detected accurately under aft coordinate system. The simulation result shows that this method can make the amplitude, frequency and phase of positive-sequence fundamental voltage be locked faster and more accurately.