  Modelling of physical systems may be a challenging task when it requires
solving large sets of numerical equations. This is the case of photovoltaic
(PV) systems which contain many PV modules, each module containing several
silicon cells. The determination of the temperature field in the modules leads
to large scale systems, which may be computationally expensive to solve. In
this context, Model Order Reduction (MOR) techniques can be used to approximate
the full system dynamics with a compact model, that is much faster to solve.
Among the several available MOR approaches, in this work we consider the
Discrete Empirical Interpolation Method (DEIM), which we apply with a suitably
modified formulation that is specifically designed for handling the nonlinear
terms that are present in the equations governing the thermal behaviour of PV
modules. The results show that the proposed DEIM technique is able to reduce
significantly the system size, by retaining a full control on the accuracy of
the solution.
