Simulation of synchronous reference frame PLL based grid connected inverter for photovoltaic application

Utilization of renewable energy resources have been the most important & prospective field to seek new energy sources to meet up the increasing demand in power all over the world specially in a developing country like India. Grid-connected photovoltaic systems are providing a viable technology for producing electrical energy by using renewable energy resources. High power density, high efficiency and reliability for this system are important design considerations along with control objectives like Maximum power point tracking (MPPT), grid synchronization, islanding detection and prevention, sinusoidal current injection into the grid, maintaining the THD within certain permissible limit (<5%), active harmonic filtering, EMI/EFI protection. This paper present a double stage converter with some ancillary features, where in the first stage, dc-dc boost conversion is achieved. Second stage dc-ac inversion is achieved using voltage source inverter. Grid synchronization is achieved by using synchronous reference frame base Phase locked loop (SRF PLL), whose performance is equally good for all the frequencies unlike the normal PLL. PI controller will be used in the current and the voltage controller.