考虑频率波动的改进瞬时电压d-q分解算法

Improved instantaneous d-q transformation considering frequency fluctuating

电压有效值的准确检测是分析电压暂降、波动和偏差的基础,是电压质量评估与抑制干扰首先要解决的重要问题.以单相电源为参考电压,采用60°延时方法构造虚拟的三相系统,借助d-q坐标变换可以对电压瞬时有效值进行计算.本文在该方法基本原理的基础上,分析了检测信号的频率波动对计算结果的影响,推导了频率波动误差公式,并在Matlab/Simulink平台下对推导结论进行了仿真验证,同时提出了基于u2d+u2q项滤波和局部均值计算的改进算法.通过仿真对比改进算法与传统算法,结果表明,改进算法对频率波动信号电压有效值的计算更准确.

The accurate detection of root-mean-square voltage is the base for analyzing voltage sag,fluctuation and deviation,and also is the primary major topic for assessing the voltage quality and suppressing interference. With the help of d-q transformation,the r. m. s. value of instantaneous voltage can be calculated by building spatial three-phase system which takes single-phase power as the reference voltage and conducts 60° delay,then adopting. This paper introduced the basic principle of this method,analyzed how the frequency fluctuation of detected signal affected calculation result,then derived frequency fluctuation error formula,conducted simulation and proved it in Matlab/Simulink platform,and proposed the improved calculation algorithm based on filtering of u2d＋ u2 qand calculating of ocal mean. Simulation result showed that the improved algorithm was more accurate than the conventional one when calculated the r. m. s. voltage of frequency fluctuation signal.