基于解耦双同步坐标变换的三相锁相环研究

提出了一种三相电压在三相电压不对称、频率突变、相位突变、注入谐波等不平衡情况下,准确锁定基波正序电压频率以及相位的方法。正(负)序同步坐标变换后,将产生二倍频交流分量,这个分量可以看作是由负(正)序电压分量导致的。通过提取负(正)序同步坐标变换下的直流分量,对正(负)序同步坐标变换下的二倍频交流分量进行补偿,构建了正负序解耦模块;同时,合理设计低通滤波器,滤除高次谐波分量,从而准确提取出了三相不平衡电压的正序基波分量。仿真结果表明,该方法能更快速准确的锁定基波正序电压的频率及相位。

Study on Decoupled Double Synchronous Reference Frame PLL

This paper proposes a method of three-phase voltage and frequency locked loop under distorted voltage conditions like voltage dip, frequency mutation, phase mutation, harmonics injected.After positive(negative) dq synchronous coordinate transformation, the dq axis voltage component contains AC component whose frequency is 2ω, which is caused by negative (positive) voltage component.After the dq axis DC voltage component is extracted from negative (positive) sequence dq synchronous reference frame transformation which compensates the 2ω AC component under the positive (negative) sequence dq transformation synchronous reference frame, and the negative-positive decoupling model is built.Meanwhile, the high-frequency harmonics are filtered by designing low-pass filter reasonably, so that positive-sequence fundamental component can be extracted from three-phase unbalanced voltage.The simulation result shows that, this method can make it that the frequency and phase of positive-sequence fundamental voltage can be locked faster and more accurately.