ROGI-PLL and Quasi-PI-Resonant Based Control Strategy for Unified Power Quality Controller

In the background of the power quality issues in the low-voltage distribution network, this paper makes a comprehensive and in-depth study on the three-phase three-wire unified power quality controller (UPQC) based on quasi-PI-resonant(quasi-PIR) controller and ROGI-PLL to improve the quality of power supply at the user’s side. Considering the typical characteristics of both harmonic current and harmonic voltage under nonlinear load condition, this paper designed and implemented a quasi-PIR controller to eliminate the selected current and voltage harmonics. Furthermore, this paper presented a reduced-order generalized integrator (ROGI) based synchronization technique, namely the ROGI-PLL to achieve excellent phase-locking performance under both unbalanced and distorted voltage condition. Finally, simulations and experimental verifications under different poor working conditions were carried out to testify the outstanding voltage compensation effect by series side of UPQC, the current compensation effect by shunt side of UPQC, and phase-locking performance by the ROGI-PLL.