Advance PLL based PV-UPQC under Adverse Grid Conditions

This paper presents a cascaded delayed signal cancellation(CDSC) based phase locked loop (PLL) employed for Photovoltaic unified power quality conditioner (PV-UPQC) to compensate grid voltage disturbance. A PV-UPQC is utilized for the purpose of mitigating power quality problems that arise from current and voltage variations in addition to the active power injection from PV. The important function of PLL is continously and precisely tracking grid voltage angle and feeding it to the PV-UPQC control. Synchronous reference frame phase-locked loop (SRF-PLL) less suited for mitigating grid voltage harmonics due to its ability to track and synchronize with the grid voltage fundamental frequency component. This paper proposes a modified PLL named CDSC PLL which mitigate this grid voltage problem. The assessment of the system’s dynamic performance is carried out by Simulating a nonlinear load in Matlab/Simulink.