Comparative Study between Different Controllers used in Three-phase Four-wire Shunt Active Filter

This paper presents a simulation of Three-Phase Four-Wire Shunt Active Filter destined to suppress harmonic currents generated by nonlinear loads in low voltage networks, and also to compensate reactive power. The identification method is based on P-Q theory using Self Tuning Filters; for-leg inverter commanded by hysteresis is used as generator of harmonic compensation currents. In order to have good performances of compensation, DC voltage of the inverter must remain constant (240V). In this paper we propose to use three different DC voltage controllers, PI, Backstepping and improved Backstepping controllers. The performances of these controllers are compared and discussed. Simulation results proved very good filtering performances with the three controllers either in transient or steady state. Improved backstepping controller gave the best results in transient state.