中文摘要：

动态电压恢复器（dynamic voltage restorer,DVR）是补偿电压暂降的一种有效电力电子装置,快速准确的电压检测是DVR精确补偿的重要前提。文中分析了现有检测算法,针对固定采样短数据窗最小方差（least error squares,LES）法的谐波敏感问题、固定采样长数据窗LES法的延迟问题,提出了一种基于递归变量可变数据窗最小方差法的暂降检测算法,采用短数据窗和长数据窗同时采样,两种方法的计算差值同时大于动作阀值时触发递归可变数据窗采样,以识别电压暂降。通过在线性和非线性负载、谐波、直流偏置等情况下进行实验分析,验证了可行性。结果表明,该方法计算量小、实现简单、实时性强,检测结果波动量小,电压暂降时相量检测时间可在5 ms内完成,且对谐波和直流偏置均不敏感,具有良好的动态响应。

英文摘要：

Dynamic voltage restorer（DVR） is a power electronic device compensating voltage sag. Rapid and accurate voltage detection is an important prerequisite for DVR control. In this paper, existing voltage sag detection methods are analyzed. To solve the problem that fixed data window least error square（LES） method is sensitive to harmonics, and that long data window LES method increases time delay, a voltage sag phasor detection algorithm based on recursive variable LES method is proposed. LES method with short and long data window is used with two calculating differences greater than operation threshold. Recursive variable data window algorithm is started to identify voltage sag. According to experimental analysis under various conditions such as linear and nonlinear loads, harmonics, dc offset, the proposed method is proved feasible. Study results indicate that, with real-time feature and high reliability, the proposed algorithm is insensitive to harmonics and dc offset and easy to implement. The calculated results have no ripple. The proposed method estimates phasor within 5ms with better dynamic response.