Understanding partial shading effects in shingled PV modules

Shingled solar modules are one of several technologies currently being considered to obtain higher solar module efficiencies. Using equivalent circuit modelling this paper investigates the robustness of shingled modules to partial shading with respect to the power produced and the power dissipated in shaded shingles. The modeling results are experimentally verified. We find that power losses in shingled modules can be larger than in conventional modules for similar shading conditions. The risk of significant local heating resulting from partial shading, potentially leading to catastrophic module failure can also be higher in shingled modules due to the substantially higher reverse biases experienced by shaded shingles. Both risks can effectively be mitigated by operating each shingled module at its own maximum power point, for instance by using module level power electronics on each module or by incorporating a sufficient number of bypass diodes into the module design.