A single-phase DG generation unit with shunt active power filter capability by adaptive neural filtering

This paper deals with a single-phase Distributed Generation (DG) system with Active Power Filtering (APF) capability, devised for utility current harmonic compensation. The idea is to integrate the DG unit functions with the shunt APF capabilities, since the DG is connected in parallel to the grid. With the proposed approach, the control of the DG unit is performed by injecting into the grid a current with the same phase and frequency of the grid voltage and with amplitude depending on the power available from the renewable sources. On the other hand, the load harmonic current compensation is performed by injecting into the AC system harmonic currents as those of the load but with opposite phase, thus keeping the line current almost sinusoidal. Both the phase detection of the grid voltage and the computation of the load harmonic compensation current have been performed by two neural adaptive filters with the same structure, one in configuration "notch" and the other complementary in configuration "band". The methodology has been tested succesfully both in numerical simulation and experimentally on a suitably devised test setup.