Passive filter design research in hybrid active filter design

There's an urgent need to apply active filter in HVDC project. The control strategy of active filter that imitating a resistor is effective to restrain the harmonic voltage. There are two strategies combined used: voltage feedback strategy and impedance offset strategy, which make the impedance of hybrid active filter extremely low at aim frequencies. The passive filter in hybrid active filter will influence the impedance finally reached. In this research, we designed several topologies of passive filter to design corresponding active filter. We calculated the impedance of each design, analysed the stability, simulate the filter performance and calculated the IGBT modules consumption. Besides, we calculated the equipment stable and transient rating voltage and current stress. Finally we concluded the suitable passive filter topology for hybrid active filter design.