AN IMPROVED ALGORITHM FOR MPPT OF PHOTOVOLTAIC SYSTEMBY ZERO –VOLTAGE SWITCHING TECHNIQUE

摘要

This paper deals with the design and experimentalrnimplementation of a maximum power point trackingrn(MPPT) for photovoltaic system , The MPP-trackerrnproposed in this paper is a study the quasi – squarernware resonant switch (QSW) DC-DC buck converter thernchoice for many high efficiency converter that havernmany advantage when compared with conventionalrnzero voltage switching quasi resonant switches andrnzero voltage transition(ZVT) converter. Which is arnthis type DC-DC buck converter operating in continuousrnand discontinuous conduction mode(CCM/DCM) torndepend on change of load. The converter is able torndraw maximum power from the PV system for arngiven irradiation level by adjusting the duty cycle ofrnconverter. Analytical models are built for the PVrnsystem and converter on the basis of the data sheetrnof manufacturer and the principle of energyrnconservation. The control technique, implement withrna single-chip microcontroller ADMC331, is based onrnthe Hill-climbing / P&O method. From the resultrnobtained it can be concluded that , the MPPT canrnincrease the overall efficiency of the system 87 % forrnconventional converter. While, the overall efficiency ofrnthe converter efficiency when the zero voltage switchingrnby this current technique is used increases 94 %rnunder different atmospheric condition. The accuracy ofrnthe proposed scheme is confirmed by experimental.