Configurable Module Topology to Recover Power Lost due to Current Mismatch

29th European Photovoltaic Solar Energy Conference and Exhibition; 194-197
Variable shading due to clouds and nearby objects has a severe impact on the energy-yield of photovoltaic installations. Due to the industry's standard of permanently series-connected cells in a PV module, partial shading creates mismatches between the I-V characteristics of cells. Apart from irradiation, temperature differences can lead to non-uniform operating conditions of the module. Current mismatch in series-connected cells reduces the total power either by limiting the extracted current or by bypassing “poorly” operating cells. Our proposal is a configurable module topology, where cell connections can be decided and altered during operation. A network of switches allows cells to be clustered at run-time based on their instantaneous MPP. Cost of additional components is taken into account and the parameters of cells, wires and switches included in the simulation model are taken from fabrication data. The proposed configurable topology can recover most of the power lost due to current mismatch and outperforms conventional topologies under non-uniform operating conditions, while the cost remains acceptable. In certain shading patterns with heavy shade, configurable topologies can produce double the power than conventional PV modules.