三相四线制变频电网的谐波及无功电流检测  

Detection for harmonics and reactive currents in three-phase four-wire variable-frequency power system

作　　者：高峰[1] 林辉[1] 

机构地区：[1]西北工业大学自动化学院,陕西西安710129

出　　处：《电机与控制学报》2014年第10期14-20,共7页Electric Machines and Control

基　　金：高等学校博士学科点专项科研基金(20106102110032)

摘　　要：为了满足变频电网提高电能质量的需要,提出一种基于通用瞬时无功理论和正序基波滤波器的谐波、无功及不平衡电流检测方法。针对基于传统通用瞬时无功理论的方法在电源电压畸变或不对称时检测不准确的问题,提出了改进算法。详细分析了正序基波滤波器的特性,采用带有自适应参数的正序基波滤波器提取正序基波电压,采用平均值法获得平均功率,同时应用到改进算法中,适应了电网基频的各种变化,克服了低通滤波器在变频工况下使用的缺陷。在飞机交流变频电网并联APF系统中对所提方法进行了仿真验证,并与Ip-Iq改进法和PHC法进行了对比。研究表明所提方法在电网基频处于不同稳态值或在稳态值间快速变化时均能实现准确,快速地检测。与传统方法相比,具有检测精度高,受变频环境影响小的优点。A new harmonic,reactive and unbalanced current detection method based on generalized instantaneous reactive power theory and positive sequence fundamental filter was proposed for improvement of power quality in variable-frequency power system.An improved algorithm was proposed to eliminate the inaccurate detection in traditional method based on generalized instantaneous reactive power theory when the voltage of power supply is distorted or unbalanced.A detailed analysis of characteristics of positive sequence fundamental filter was made firstly.The fundamental positive sequence voltage was extracted by positive sequence fundamental filter and the average power was obtained by the average method.The improved algorithm with adaptive parameters can adapt any change of fundamental frequency of power system and can overcome the defect of LPF under variable-frequency conditions.The proposed method,improved Ip-Iq method and PHC method were applied in simulation of the variable-frequency aircraft electric power system.The comparison of simulation results showed that proposed method can detect the harmonics,reactive and unbalanced current accurately and rapidly when the grid fundamental frequency is in different steady-state value or is changing rapidly between two steady-state values.The proposed method has advantage of accurate detection and strong robustness over traditional methods.

关 键 词：变频电网 三相四线制 有源电力滤波器 通用瞬时无功理论 正序基波滤波器 谐波检测 

分 类 号：TM714.3[电气工程—电力系统及自动化]