Single-phase grid-connected photovoltaic system based on ripple correlation control maximum power point tracking

This work presents a comparison of ripple correlation control maximum power point tracking (MPPT) technique and the modified version of the same MPPT applied to single-phase, single-stage, grid-connected photovoltaic (PV) system, as the technique is fast and suitable for fast changing environmental conditions. Both the techniques are compared on the basis of the time taken to reach (track) the MPP, operating point oscillations about MPP and the dependence of the algorithms, if any, on array configuration and parameters. An LCL-Filter based grid connected inverter with proportional-resonant (PR) current controller is suggested to provide power to the line with unity power factor and the inverter offers much less total harmonic distortion. The focus is on presenting a systematic design procedure for AC current, DC voltage controllers for the VSI and low complexity grid synchronization method. The complete system is numerically simulated in MATLAB and the results are presented for rapidly changing irradiation levels.