An Indirect Approach to Control an Active Capacitor

Jun Lin*, George Weiss

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


We propose an indirect approach to control an active capacitor, realized using a bidirectional converter, meant for dc voltage filtering (ripple elimination). This active capacitor can replace large, expensive, and unreliable electrolytic capacitors connected on a dc bus for power filtering. It can deal with a wide frequency band of harmonics so that it does not need a priori knowledge of the ripple frequencies. Thanks to the simple decentralized controller proposed in this paper, our active capacitor can be connected directly to the dc bus like a passive filtering capacitor, and no extra connections are needed. Compared with the various direct approaches, a unique feature of the proposed indirect approach is that the buffering capacitor energy VS2 is directly regulated and much better dynamics of VS2 under sudden load variations are obtained. The control algorithm has been verified by both simulation and experiments, with our circuit being connected to a 350-W commercial power factor compensator.

Original languageEnglish
Article number8723569
Pages (from-to)2898-2906
Number of pages9
JournalIEEE Journal of Emerging and Selected Topics in Power Electronics
Issue number3
StatePublished - Sep 2020


FundersFunder number
Tel Aviv University


    • Active capacitor
    • active power filtering
    • decentralized control
    • fractional-order filter approximation
    • impedance emulation
    • plug-and-play (PnP)
    • ripple elimination


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