基于i_(p)-i_(q)法的改进谐波电流检测方法  

Improved harmonic current detection method based on i_(p)-i_(q) method

作　　者：王清亮[1] 应欣峰 宋曦 杨林 Wang Qingliang;Ying Xinfeng;Song Xi;Yang Lin(School of Electrical and Control Engineering,Xi′an University of Science and Technology,Xi’an 710054,China)

机构地区：[1]西安科技大学电气与控制工程学院,西安710054

出　　处：《电子测量技术》2022年第6期72-78,共7页Electronic Measurement Technology

基　　金：国家自然科学基金(51777166)项目资助。

摘　　要：针对现有谐波电流检测算法难以准确检测次同步谐波和超同步谐波电流的问题,提出了一种改进的i_(p)-i_(q)谐波电流检测算法。首先明确了低通滤波器平缓衰减性和动态调节能力不足是谐波电流检测精度不高的根本原因,然后采用在基频附近具有陡峭衰减特性的自调谐滤波器取代低通滤波器,实现了在不降低整数次谐波电流滤除效果的同时加强了次同步谐波和超同步谐波电流的检测效果;通过基于改进双曲正弦函数的自适应滤波算法改善i_(p)-i_(q)算法的动态特性,建立步长参数与谐波补偿电流的函数关系,实现步长参数的动态调整,克服了次同步谐波和超同步谐波电流的时变准稳态特性对谐波检测的不利影响,并通过电流畸变率、谐波含有率指标来评价改进算法的检测效果,仿真实验验证了改进算法的有效性。相较于传统i_(p)-i_(q)谐波电流检测法,本文方法可将谐波电流检测精度提高了23.59%,实现了次同步谐波和超同步谐波环境下对谐波电流的准确检测。Aiming at the problem that the existing harmonic current detection algorithms are difficult to accurately detect subsynchronous harmonic current and supersynchronous harmonic current, an improved i_(p)-i_(q)harmonic current detection algorithm is proposed. Firstly, it is clear that the low pass filter gentle attenuation characteristics and insufficient dynamic adjustment ability are the fundamental reasons for the low harmonic current detection accuracy. Secondly, the low pass filter is replaced by a self-tuning filter with steep attenuation characteristics near the fundamental frequency. The self-tuning filter can enhance the detection effect of subsynchronous harmonic current and supersynchronous harmonic current without reducing the filtering effect of the integer harmonic current;The dynamic characteristics of i_(p)-i_(q)algorithm are ameliorated through the adaptive filtering algorithm based on the improved hyperbolic sinusoidal function. The adaptive filtering algorithm establishes the functional relationship between the step size parameter and the harmonic compensation current, and realizes the dynamic adjustment of the step size parameter. This algorithm overcomes the adverse influence of the time-varying quasi steady state characteristics of subsynchronous harmonic current and supersynchronous harmonic current on harmonic detection. In this paper, the detection effect of the improved algorithm is evaluated by current distortion rate and harmonic content rate. Simulation experiments verify the effectiveness of the improved algorithm. Compared with the traditional i_(p)-i_(q)harmonic current detection method, this method can improve the detection accuracy of harmonic current by 23.59%, and realize the accurate detection of harmonic current in the environment of subsynchronous harmonic and supersynchronous harmonic.

关 键 词：次同步谐波 超同步谐波 i_(p)-i_(q)法 低通滤波器 自调谐滤波器 自适应滤波 

分 类 号：TM935[电气工程—电力电子与电力传动]