基于改进i_(p)-i_(q)理论的谐波与无功电流检测方法研究

Research on Harmonic and Reactive Current Detection Methods Based on Improved i_(p)-i_(q)Theory

基于传统i_(p)-i_(q)理论谐波与无功电流检测原理,提出了一种改进的检测方法。该改进一是在相电压提取环节,采用T/3延时算法代替锁相环模块,避免了三相电压不对称时因负序电压存在产生的相位差后导致无功电流检测存在误差;二是在低通滤波环节,采用滑动平均滤波器(MAF)代替低通滤波器,利用MAF滑动平方特性,准确获得电流正序基波信号,用以弥补传统低通滤波器结构复杂且检测存在延时问题,能够实现快速、准确的模拟量数据采样。最后利用MATLAB/SIMULINK软件对所提出方法与传统i_(p)-i_(q)理论检测方法进行仿真对比,仿真证明系统的三相电压不对称工况下,所提出的检测方法仍能够精确对系统谐波与无功电流进行检测,其检测精度高于传统i_(p)-i_(q)理论检测方法。

Based on the traditional i_(p)-i_(q)theory of harmonic and reactive current detection,an improved detection method is proposed in this paper.The first improvement is to replace the phase-locked loop module with the T/3 delay method in the phase voltage extraction process,which avoids errors in reactive current detection caused by phase differences resulting from the negative sequence voltage when the three-phase voltage is asymmetric;In the low-pass filtering process,a moving average filter(MAF)is used instead of the low-pass filter,and the MAF sliding square feature is used to accurately obtain the positive-sequence fundamental signal of the current.This compensate is for the complex structure of the traditional low-pass filter and detection time problems,making harmonic and reactive current detection faster and more accurate.In this paper,MATLAB/SIMULINK software is used for modeling and simulation comparison.The simulation results show that the harmonic and reactive current detection methods described in this paper can quickly and accurately detect harmonics and reactive current when the three-phase voltage of the system is asymmetric.,The detection accuracy of the proposed method is higher than that of the traditional i_(p)-i_(q)theoretical detection method.