CAJ | 학술논문

现代谱估计方法逐渐被应用于电力谐波及间谐波的超分辨率检测与分析,其中的多重信号分类方法(MUSIC)算法最具代表性.然而,常规谱MUSIC算法在分析电力谐波时必须将实值信号转换为复频率信号,因而计算复杂度较高;此外,其伪频谱的峰值搜索过程也存在着类似栅栏效应,导致其频率分析精度有限.为了改善谱MUSIC算法对电力谐波的分析精度,本文基于子空间分析理论提出了针对实值周期信号的谱MUSIC频率检测方法,推导并给出了其伪谱函数的表达式.在此基础上,还利用Newton-Raphson算法对伪谱峰值进行迭代求精,进一步提高了谐波频率的估计精度.仿真结果表明:实值MUSIC伪谱更能有效区分真实谐波谱峰与噪声伪峰,同时本文方法的计算复杂度远远低于原有复值谱MUSIC算法,而频率估计精度与求根MUSIC算法接近,非常有利于电力谐波参数的准确获取.
현대보고계방법축점피응용우전력해파급간해파적초분변솔검측여분석,기중적다중신호분류방법(MUSIC)산법최구대표성.연이,상규보MUSIC산법재분석전력해파시필수장실치신호전환위복빈솔신호,인이계산복잡도교고;차외,기위빈보적봉치수색과정야존재착유사책란효응,도치기빈솔분석정도유한.위료개선보MUSIC산법대전력해파적분석정도,본문기우자공간분석이론제출료침대실치주기신호적보MUSIC빈솔검측방법,추도병급출료기위보함수적표체식.재차기출상,환이용Newton-Raphson산법대위보봉치진행질대구정,진일보제고료해파빈솔적고계정도.방진결과표명:실치MUSIC위보경능유효구분진실해파보봉여조성위봉,동시본문방법적계산복잡도원원저우원유복치보MUSIC산법,이빈솔고계정도여구근MUSIC산법접근,비상유리우전력해파삼수적준학획취.
In recent years, modern spectral estimation methods, especially the MUSIC (Multiple Signal Classification) algorithms, are gradually used for high-resolution power harmonic analysis. However, most of them are proposed to detect frequencies of complex signals so that any real-valued signal should be transformed into complex form. The preprocessing may lead to higher computation burden. In addition to this, the picket-fence effect also exists in searching spectrum peaks, which causes low analyzing precision. To overcome these drawbacks, a real-valued MUSIC algorithm for power harmonic analysis is proposed in the paper based on subspace decomposition theory. And the computing method of pseduospectra is also derived. Furthermore, to improve the measuring accuracy of harmonics, Newton-Raphson algorithm is adopted to optimize the harmonic frequencies significantly. Simulation results show that: the spectral peaks of true harmonic components are more distinct from false peaks caused by noise in the real-valued MUSIC,and the computational complexity is notably lower than that of the classic MUSIC,as well as the detecting precision is close to that of root-MUSIC algorithm which is quite time-consuming.