改进dq变换的动态电压恢复器检测新方法

Improved dq Transform Algorithm for Dynamic Voltage Restorer Detection

为了满足动态电压恢复器的电压暂降检测实时性和准确性要求,提出了基于自适应最小均方LMS(leastmean square)滤波器及其软件锁相环的改进dq变换新方法。结合自适应LMS算法与延时正反馈构成数字滤波器,将其应用于dq变换的软件锁相环控制过程中。并使滤波环节提前,采用求导法代替传统低通滤波器瞬时分离出dq坐标系下的直流分量。该方法可提高电压采样值的准确度,实现有效锁相,提高电压暂降检测精度及响应速度。通过PSCAD/EMTDC进行仿真验证,结果表明了该方法的有效性。

To meet the real-time and accuracy requirements for voltage sag detection in dynamic voltage restorer,an improved dq transform algorithm based on adaptive least mean square（LMS）filter and software phase-locked loop is proposed.The adaptive LMS algorithm with time delayed feedback is applied to the digital filter,which is applied to the control process of software phase-locked loop. The filtering process is conducted in advance,where instead of the traditional low pass filter,derivative method is used to isolate the DC component under dq coordinate system instantaneously. The proposed method can improve the accuracy of voltage sampling value,accomplish phase lock,and improve the accuracy and response speed of voltage sag detection.A simulation model built in PSCAD/EMTDC validates the effectiveness of the proposed method .