A SOGI-FLL based control algorithm for single phase grid interfaced multifunctional SPV under non ideal distribution system

This paper deals with a single phase grid interfaced SPV (Solar Photo Voltaic) system. The proposed multifunctional system also helps in power quality improvement in single phase distribution system. A two stage system is used in the presented work. The first stage is a boost converter, which serves the purpose of MPPT (Maximum Power Point Tracking). The second stage is a VSC (Voltage Source Converter), which performs reactive power compensation, harmonics elimination and feeding solar energy into the grid. A SOGI-FLL (Second Order Generalized Integrator with Frequency Lock Loop) based control algorithm is proposed for control of VSC. A feed forward term for solar contribution is used to improve the dynamic response. A PI controller is used to regulate the DC link voltage to desired value. A wide range of simulation studies are carried out to show all features of proposed system. The system is tested considering realistic non-ideal grid conditions. The performance of proposed system is found satisfactory for wide variation in grid voltage. The THD of grid current is well under IEEE-519 standard.