Unified power quality conditioner in a grid-connected photovoltaic system

This paper presents a system that provides photovoltaic generation as well as the functions of a unified power quality conditioner. The system can be controlled for current harmonics and reactive power compensation simultaneously by using a converter operating as active shunt filter. The other converter is used as active series filter and it compensates voltage harmonics or voltage sags and swells. Using only an inverter in photovoltaic energy conversion process, the system presents increased efficiency when compared to the conventional systems. The synchronous reference frame method is used to control the three-phase converters. Simulation results demonstrate the good performance of the proposed configuration. Experimental results corresponding to the operation of the series filter as voltage sag compensator are presented.