Sliding mode control technique for indirect current controlled active filter

This paper deals with a DSP based implementation of a three-phase active filter (AF) to compensate harmonics of a nonlinear load. The AF system suffers from the problems of switching ripples and these ripples contribute considerably to the Total Harmonics Distortion (THD) in the supply current. This investigation proposes a new and simple approach for the elimination of switching ripples. In closed loop control of the AF sliding mode control (SMC) technique is used. A current controlled voltage source inverter (CC-VSI) based configuration is used as an AF. A three-phase diode bridge rectifier with R-L load is considered as a nonlinear load. The prototype model of the AF is tested, steady state and transient results are given and discussed in detail.