Harmonic compensation in shunt active power filters by applying kalman filtering for estimation of the averaged load conductance

Load current components which contribute to non-active power consumption in electrical systems increase losses in distribution lines and reduce the power system efficiency. Shunt active power filters (APFs) can be employed to reduce the non-active power flow and, due to their characteristics, are more effective than passive filters under dynamical conditions. The main drawback of SAPFs is the controller complexity, which must evaluate the instantaneous values of the compensation current and ensure that the injected current at the point of common coupling (PCC) of the SAPF, the electrical grid and the distorting load, matches the reference one. This paper presents a new discrete technique to obtain the reference signals of a generalized N-phase SAPF based on the instantaneous estimation of the FBD-method load conductance. This method allows non-active power components to be compensated under stationary or dynamical conditions (i.e. voltage dips and load current transients). Experimental results obtained on a three-phase laboratory prototype demonstrate the effectiveness of the proposed method.