Design of Single-Phase Grid-Connected Based on Dual-MPPT for Photovoltaic Generation Systems

A new development of Dual-MPPT algorithm for single-phase grid-connected photovoltaic generation systems under variation of irradiance is presented in this research. This method is extract the maximum available power from PV module by making them operates at the most efficient output and fastest transient response. In order to accelerate the tracking speed, an incremental conductance based integral proportional (IP) controller and integrated with a new maximum power point tracking (MPPT) based on control region for operating the dc–dc converter is also proposed, which uses the reference voltage information from the tracking algorithm to shift the operation toward the maximum power point(MPP). For synchronizing to grid voltage is used a synchronization algorithm by using two phase locked loop (PLL) as a reference and feedback for the synchronization controller. Simulation and experiment results show that the Grid-Connected controller functions well in regulating the output voltage and current under variation of irradiance. The developed controller can regulate the output voltage and current in the same phase under irradiance variation from 1000 W/m to sudden irradiance of 600 W/m, and from 600 W/m to sudden irradiance of 1200 W/m. The tracking time with this controller is about one-sixth as compared to an incremental conductance. When the system connected to the grid at the time of 3.5s the output voltage experiences small drop before it is recovered to stable condition. It can be concluded that the developed control system works well satisfying the design specification. Keywords— grid-connected; dual-MPPT; integralproportional; phase locked loop; controller; synchronization