A new SRF-based power angle control method for UPQC-DG to integrate solar PV into grid

Abstract

In this paper, a new synchronous reference frame theory–based power anglecontrol (PAC) method for unified power quality conditioner with distributedgeneration (UPQCDG) is proposed for effective grid integration of solar PV. InUPQCDG, shunt active power filter (APF) feeds power from distributed genera-tor to load, apart from supplying reactive power demand, which leads to increasein VA burden, hence its rating. Power angle control method aims at effective uti-lization of series and shunt APFs through sharing of reactive power to reduceVA burden on shunt APF. Proposed PAC method is based on instantaneousthree-phase power estimation technique, which is simple and robust and utilizesalready available measurements of UPQCDG. Performance of proposed systemis tested in the presence of nonlinear and reactive loads with solar PV genera-tion system. Dynamic performance of system is studied during grid disturbancessuch as voltage sag and swell, solar irradiation variation, and change in load.Effectiveness of proposed method is validated using real-time simulation per-formed in Opal-RT, in which electrical circuit of UPQCDGis simulated on FPGAcomputation engine with submicrosecond time step to emulate real hardwareclosely.