MAXIMUM PHOTOVOLTAIC POWER TRACKING - AN ALGORITHM FOR RAPIDLY CHANGING ATMOSPHERIC CONDITIONS

As the maximum power operating point (MPOP) of photovoltaic (PV) power generation systems changes with changing atmospheric conditions (e.g. solar radiation and temperature), an important consideration in the d esign of efficient PV systems is to track the MPOP correctly. Many max imum power tracking (MPT) techniques have been considered in the past but techniques using microprocessors with appropriate MPT algorithms a re favoured because of their flexibility and compatibility with differ ent PV arrays. Although the efficiency of these MPT algorithms is usua lly high, it drops noticeably in cases of rapidly changing atmospheric conditions. The authors have developed a new MPT algorithm based on t he fact that the MPOP of a PV generator can be tracked accurately by c omparing the incremental and instantaneous conductances of the PV arra y. The work was carried out by both simulation and experiment, with re sults showing that the developed incremental conductance (IncCond) alg orithm has successfully tracked the MPOP, even in cases of rapidly cha nging atmospheric conditions, and has higher efficiency than ordinary algorithms in terms of total PV energy transferred to the load.