Retracted: Study of Low Voltage Distortion Control Strategy for PV System

According to the operating characteristics of a grid-connected PV system this paper develops an improved PLL based on second order generalized integrator and adaptive filter. This paper makes a PV grid-connected control system model, analyzes characteristic of traditional phaselocked loop (PLL), and designs an improved PLL based on second order generalized integrator(SOGI) and adaptive filter (AF). Simulate the improved PLL under both three phase voltage balance and unbalance conditions on Matlab platform. The simulation results show that the improved PLL has a good performance of tracking and self-adaptive filter discrimination. It also shows that the improved PLL reduces distortion rate of voltage and induces less harmonic while working which improves power quality of the gridconnected system.