谐波电流的概率分析

对于由大量变流器负载组成的系统，其总的谐波电流将远远小于各个变流器的谐波电流的矢量和。本文利用概率模型对多台变流器负载产生的决的谐波电流幅值的概率分布作研究，并利用Ｍｏｎｔｅ Ｃａｒｌｏ方法对所得结论加以验证。这种方法可以用于系统的谐波估计，多台变流器系统的谐波分析。

HARMONICS ANALYSIS FOR MULTI CONVERTER SYSTEMS

In this paper,the sum of harmonic currents of a multi converter system is analyzed by means of probability method because of its random feature.A series of formula to calculate the 5 important parameters of the normal distribution of the sum of harmonics are derived for a group of VVVF loads,provided that the firing angle of each converter follows the mean distribution.The multi converter system is simulated further by Monte Carlo method,and the conclusions are in good concordance with the analysis model method.It is found that the random propriety of the sum harmonics becomes more evident as the number of converters,the harmonic order increases and the distribution range of the firing angle widens.The correlation of the sum harmonic magnitude and phase is studied and it is concluded that the correlation decreases with the increase of the converter number and the distribution range of firing angle as well as the harmonic order.