Observation and nonlinear control single phase half bridge shunt active power filter

The problem of controlling single-phase half bridge shunt active power filter (HBSAPF) is addressed in this paper in presence of nonlinear loads. The control objective is twofold: (i) compensation of harmonic currents and the reactive power absorbed by the nonlinear load; (ii) regulation the DC bus voltage of the converter. First, an observer based on Kalman technique, is designed to estimate the network voltage which is not accessible to measurement. Second, a nonlinear controller that involves two loops in cascade, an inner-loop is designed, using the Backstepping technique, to provide the harmonic compensation and an outer-loop is designed to regulate the DC bus voltage of the converter. The controller performances are illustrated by simulation in Matlab/Simulink environment.