A power electronic controller for PV-tied Grid-connected system with single parameter sensing for mppt using boost converter and line-commutated inverter

A simple power electronic controller employing boost converter and SCR based line commutated inverter (LCI) for interfacing PV array with utility grid has been proposed. The variable voltage of PV array is boosted to a fixed value and is connected to the line commutated inverter, which operates with a fixed firing angle more that 90°. The grid voltage and firing angle will determine the constant dc voltage of boost converter. As the output of boost converter is maintained constant, any variation in PV array output voltage will result in variation of dc link current. Thus MPPT is achieved by tracking dc link current alone. The complete scheme has been constructed and experiments have been conducted on a 84 V, 4.7 A PV array interfaced with a utility grid of 110 V and the results are furnished. An 8051 μC has been employed for generating trigger pulses to the SCRs and a simple analog controller for varying the duty ratio of the boost converter. The experimental results are compared with simulation results and a close agreement between them is observed.