PLL Based Photovoltaic System of LCL Three-Phase Grid Connected Inverter with and Without SVPWM Technique

A photovoltaic (PV) system uses the sun’s energy to produce electricity in an endless supply. PV systems are integrated with traditional residential and commercial electrical systems to satisfy the consumer side’s electrical energy needs. This paper explains power conversion stages between PV panel to three phase utility grid. PV panel requires a power interfacing circuit to make electric isolation and maximize the voltage with adjusted duty cycle. Power interfacing circuit with a dc link will deliver the power to three phase utility grid by connecting three phase voltage source inverter (VSI). However, semiconductor switching in inverter cause harmonics. Such harmonics can be suppressed by using LCL type grid connected filter. Meanwhile for VSI, a phase locked loop (PLL) based algorithm and a current control feedback technique is employed in the circuit with the help of Direct-Quadrature (dq) theory and PWM techniques like Space vector pulse width modulation (SVPWM) and Sinusoidal pulse width modulation (SPWM). Simulation results are carried out for active power injection from PV panel to the constant three phase utility grid.