Hybrid power electronic controller for combined operation of constant power and maximum power point tracking for single-phase grid-tied photovoltaic systems

This study presents a hybrid technique that offers constant power operation for single-phase grid-tied photovoltaic (PV) systems while performing maximum power point tracking function. A boost converter and a line commutated inverter (LCI) have been used for interfacing PV array with utility grid. Fixed firing angle of the LCI keeps the dc-link voltage constant and the boost converter extracts maximum power from the solar PV array by simply adjusting the duty ratio of the boost converter. A low-capacity battery bank connected at the dc link is used to deliver constant power to grid. Harmonic filter is eliminated as the system inherently delivers quality supply with reduced current harmonics. PIC microcontrollers have been programmed for generating pulses to the inverter and the boost converter. The system has been simulated in MATLAB/Simulink and the simulation results are presented. The parameters of a PV panel rated for 100 W, 21.5 V and 6.83 A have been used for the simulation. Experiments have been conducted on the 21.5 V, 6.83 A PV panel for obtaining a constant power of 80 W with varying irradiation and the results correlate with the simulation study.