Output feedback control of a three-phase shunt active power filter

Abstract

A three-phase shunt active power filter is generally used to compensate current harmonics demanded by non-linear loads, so that the source current remains quasi-sinusoidal and therefore the level of harmonic pollution in an electrical network is decreased. Most of the existing classical control methods for a three-phase shunt active filter usually lead to a non-linear control problem due to the non-linearity of the Park transformation. In a previous work, a compensated three-phase power distribution system has been successfully represented by a dasiasimplepsila linear state space model. Its state matrix contains a fundamental parameter used to extract the desired frequency component of any electrical signal. The linearity of the model enables one to use the control theory in a linear context in order to build a control system. In this paper, a three-phase shunt active filter is driven using output feedback control with Hinfin performance in order to reduce the number of measured outputs. The control method is mainly based on Linear Matrix Inequalities which are considered as a powerful tool for numerically solving control problems. The ability of the synthesized controller to provide an acceptable harmonic compensation is investigated through both numerical simulations on a prototype built in Simulink and experimental results.