Analysis and Design of a New Current Controlled Switched Capacitor Filter for Harmonic Mitigation

This article presents a novel switched capacitor (SC) type single-phase active filter. The power circuit is simple, requiring only three bi-directional switches, as well as the control circuit that is based on hysteresis current control. There is no need for employing a capacitor voltage regulation loop if the reactive components are chosen adequately. The operating principles are described and a logic circuit for generating the gating signals of the switches is presented. A design approach is proposed and the feasibility of the topology is verified by simulation and experimental results. An interesting feature of the proposed scheme is that considerable harmonic mitigation can be achieved with an average switching frequency of a few kHz.