Improved PV Module Performance under Partial Shading Conditions

Abstract

In a typical series-connected photovoltaic module with three bypass diodes, not all of the energy generated by the individual cells in the module can be collected when one or more of the cells in the module are partially shaded. In this work, various photovoltaic (PV) module layouts are investigated, using both full-size solar cells and halved solar cells. The performance of these module layouts is investigated under conditions where one or more cells in the module are partially shaded. A solar cell equivalent circuit model has been implemented in the SPICE soft ware Micro-Cap to investigate several different module configurations. Module configurations investigated include a standard 72-cell module with 3 bypass diodes, one new configuration with a series of six matrices (whereby each matrix consists of two parallel strings of 12 halved cells each) with 3 bypass diodes, and another configuration with a series of 72 cells (whereby each matrix consists of two halved cells in parallel) with 3 bypass diodes. In the simulation, a shadow with zero transmittance was simulated to pass over the area of one 6-inch full-size solar cell in the corner of the module from two orthogonal directions, and the maximum power was calculated for each of the investigated module configurations. Simulation results show that the series-parallel hybrid connection of cells within a module has a significant improvement on the power output of the PV module under partial shading conditions.