A single-phase active power filter based in a two stages grid-connected PV system

In this paper a single-phase active power filter based in a two stages grid-connected photovoltaic system with is presented. The proposed system can not only inject PV power into utility but can act always as an active power filter to compensate the load harmonics and reactive power such that the input power factor is unity independently of the solar radiation. In sunny days, the system processes all the reactive and active load power and the excessive power from the PV module can be fed to the utility. On the other hand, on cloudy days for instance, if the PV power is not enough, the system processes all the reactive load power and the shortage of load active power is supplemented by the utility. Besides, just using one current sensor, the control strategy is simpler and of easy practical implementation.