磁通补偿串联APF采用多绕组变压器的不必要性

Dispensability of the Series Hybrid APF Based on Magnetic Flux Compensation with Multiple Secondary Windings Series Transformer

为促进基于基波磁通补偿的有源滤波器的实际应用,对传统的采用多绕组串联变压器实现大容量的方式进行了研究。首先将串联变压器和逆变器作为一个整体,建立串联变压器谐波等效阻抗的精确数学模型。然后根据串联变压器的匝比k和二次绕组数N的相互关系,将多绕组技术分为"分裂法"和"增加法"两种方式,分别分析串联变压器的谐波等效阻抗。结果表明:对于"增加法",当N足够大时,串联变压器在主要谐波频段上相当于导线,滤波效果变差;而对于"分裂法",滤波效果不变,但逆变器容量增加N倍。因此认为串联变压器采用多绕组技术是不必要的。

In order to improve the industrial application of the series hybrid active power filter based on the fundamental magnetic flux compensation, We proposed a traditional large capacity achieving method which adopts multiple winding series transformer. Taking the series transformer and the inverter as a whole, we established an accurate mathematical model of the equivalent harmonics impedance of the series transformer. Then based on the relationship between the numbers of the secondary winding N and the tuna＇s ratio k of the series transformer, multiple winding technologies were divided into ＂add＂ and ＂divide＂ ways. Then, we discussed the equivalent harmonics impedance of the series transformer. Conclusions are drawn form the analysis as follows. For the ＂add＂ way, the series transformer can be equivalent to a wire under the main harmonic frequency when N is very large. Thus the filtering of the APF will be ineffective. For the ＂divide＂ way, the total capacity of the inverter increases N times as the filtering effects remain unchanged. It can be concluded that it is not necessary to adopt multiple secondary windings series transformer.