Centralized and modular architectures for photovoltaic panels with improved efficiency

The most common type of photovoltaic (PV) installation in residential applications is the centralized architecture. This realization aggregates a number of solar panels into a single power converter for power processing. The performance of a centralized architecture is adversely affected when it is subject to partial shading effects due to clouds or surrounding obstacles, such as trees. An alternative modular approach can be implemented using several power converters with partial throughput power processing capability. This paper presents a detailed study of these two architectures for the same throughput power level. The study compares the overall efficiency of these two different topologies, using a set of rapidly-changing real solar irradiance data collected by the Solar Radiation Research Laboratory (SRRL) at the National Renewable Energy Laboratory (NREL). This provides an opportunity to study both schemes using real measured data. The output power of both the topology is compared against the panel ideal power. Hence, the efficiency is overall in nature. The electrical efficiency is another form of computation which uses the panel maximum available power as input instead of panel ideal power. The paper uses overall efficiency for all analysis. The buck converter along with the Perturb & Observe maximum power point tracking algorithm were selected to perform the study. A detail power loss analysis is also presented in the paper. Analytical results are validated through detailed computer simulations using the Matlab/Simulink mathematical software package.