Analytical study and numerical simulation of the static and dynamic performances of combined shunt passive and series active filters

Harmonics generated by power converters have become a serious problem for the AC mains as they can only be removed by using bulky passive filters. Besides, harmonic compensation by shunt passive filters may cause undesirable interference such as resonance with the AC mains. To solve this problem, the authors propose a combined system of a shunt passive and series active filters. This system is self-adaptable and only a small power active filter is needed. The choice of the control algorithm, together with the AC mains and nonlinear load parameters determine its performance in static operation as well as in dynamic mode resulting from fluctuating loads. In this paper, the calculation of harmonic current references is considered first. Secondly the compensation characteristics of the whole filter are studied in steady state mode and some simulation results are presented. Finally the dynamic of the harmonic compensation is studied when the nonlinear load varies, so as to the appreciate the series active filter effect on harmonic compensation