电压间谐波对紧凑型荧光灯光闪变效应的实验研究

为进行实验研究,对IEC闪变仪模型中的加权滤波器进行分解,提出闪变仪的分解模型,该模型可直接导入实验获得的光通量信号以进行光闪变强度Pst计算,实验验证了该模型的可行性和有效性;设计并建立了实验装置,利用高准确度照度计采集紧凑型荧光灯在含有特定间谐波频率和幅值的电压下的光通量输出,使用闪变仪分解模型,对其在间谐波电压下的光闪变效应进行实验研究,获得了紧凑型荧光灯在不同间谐波频率和含量下的光闪变强度Pst,并据此提出了针对紧凑型荧光灯光闪变的间谐波限制曲线。     

第7讲 公用电网间谐波标准

介绍间谐波的基本概念及其产生的影响,国际相关标准对间谐波限值的规定,并详细解析GB／T24337—2009《电能质量公用电网间谐波》对间谐波限值的规定,间谐波的测量和取值,及抑制间谐波的措施。     

电压间谐波分量对荧光灯闪变效应的研究

运用调制理论,对自激式电子镇流器荧光灯在间谐波导致的闪变电压下的功率波动进行理论分析,得到了在电源电压中含间谐波分量时荧光灯的功率响应,建立了荧光灯瞬时功率波动特征与间谐波特征之间的关系曲线。利用Matlab/Simulink软件对该研究对象进行的仿真和实验研究,验证了理论分析结果的正确性。理论分析和实验结果均表明电源电压中的间谐波分量可能导致荧光灯闪变,且闪变频率与间谐波造成的电压波动频率相同。荧光灯瞬时功率波动特征与间谐波特征之间关系的建立,有助于进一步对荧光灯在间谐波电压条件下的闪变效应进行评价方法研究,及其间谐波闪变限制标准的制定。     

A backstepping high-order sliding mode voltage control strategy for an islanded microgrid with harmonic/interharmonic loads

This paper presents a new nonlinear voltage control strategy based on backstepping control and a high-order sliding mode differentiator for an islanded microgrid. The microgrid consists of multiple distributed generation (DG) units with an arbitrary configuration that can be parametrically uncertain or topologically unknown. The proposed controller robustly regulates the microgrid voltages in the presence of parametric uncertainties, unmodeled dynamics, load imbalances, and nonlinear loads with harmonic/interharmonic currents. In contrast to existing methods, the controller does not need to know the frequency of harmonic and interharmonic current of microgrid loads that lead to the reduction of the steady-state error of the voltage controller in the frequency of unknown harmonics and interharmonics. The MATLAB/SimPowerSystems toolbox has verified the proposed control strategy's performance.     

Spectral correction-based method for interharmonics analysis of power signals with fundamental frequency deviation

In this paper, a spectral correction-based algorithm for interharmonic computation is proposed for especially highly fluctuating fundamental frequency cases in the power system. It has been observed and reported that fluctuating demands of some loads such as arc furnaces, or disturbances and subsequent system transients make the fundamental frequency of the power system deviate and this causes non-existing interharmonics to appear in the spectrum due to grid-effect when a standard window length is used for the entire FFT process. The proposed method uses a synthetic waveform produced at the fundamental frequency and amplitude to determine the amount of the leakage due to the grid-effect at each frequency. Then the leakage is subtracted from the original FFT of the signal to correct the frequency spectrum. It has been shown that the leakage effect caused by the fundamental frequency variation is avoided with a correction algorithm applied after FFT and the error in the first interharmonic computation due to frequency deviation is reduced to zero exactly if the fundamental frequency can be determined accurately. Both simulative and field data tests have been performed. The method does not require online sampling frequency or FFT window length adjustment and it is simple to implement.     

基于回归型支持向量机的间谐波检测与Labview的实现

支持向量机方法以结构风险最小化为原则为机器学习提供了一个崭新的角度,以广泛应用于模式识别和函数拟合中。以支持向量机方法为理论基础,并以当今应用广泛、功能强大的图形化软件开发集成环境LabVIEW为开发平台, 设计实现了间谐波检测系统。该系统具有结构简单、精度高等特点,能准确地检测出间谐波,具有很好的实用价值。     

Modeling of the behavior of power electronic equipment to grid ripple control signal

The paper presents time-domain simulation for power electronic device equivalent impedance computation at ripple control signal frequency.     

MUSIC算法在间谐波信号检测中的应用及优势

间谐波问题是影响电力系统安全稳定的重要因素之一.传统方法无法在短采样时间内检测出信号的谐波和间谐波,且误差较大.因而提出了采用空间谱估计算法中的MUSIC算法进行检测,并通过仿真与Burg算法进行比较,验证了方法在短采样时间内检测出信号基波附近间谐波的优势.     

一种基于自回归模型的间谐波谱估计的改进算法

间谐波的频率是基频的非整数倍，频谱随时间而变化，具有随机性，因此间谐波是随机信号。该文首先介绍平稳随机信号的AR模型和Burg算法的基本原理，然后分析Burg算法在处理正弦信号时出现谱峰偏移的原因。在此基础上该文提出了一种基于AR模型的间谐波谱估计改进算法。该算法通过直接求解在预测误差功率最小意义下的较低阶AR模型系数，再递推计算高阶系数，减小了谱估计的谱峰偏移。仿真结果表明，该算法明显改善了谱估计的性能，而且只要用比较短的数据即可得出较好的间谐波谱估计。