Modelling spatial electrical properties in photovoltaic modules using PV-oriented nodal analysis

Authors: X. Wu, M. Bliss, A. Sinha, TR. Betts, R. Gupta, R. Gottschalg

39th Annual Conference of the IEEE Industrial Electronics Society (IECON 2013), Vienna, Austria, pp. 8098-8103, November 2013

Inhomogeneities in photovoltaic (PV) devices can cause spatially non-uniform performances and hence, electrical mismatches which will reduce the overall power generation. A distributed electrical modelling technique is developed to investigate localised electrical properties and their impacts on the change of power generation of PV modules. The proposed modelling approach introduces a hierarchical architecture built up from the diode-model based sub-cell level to the module level. Resistances of the front and the back contacts are introduced to establish lateral current flows. A PV-oriented nodal analysis method is developed to enable the spatially-resolved quantitative analysis of electrical operating points by given localised properties. The principle of the PV-oriented nodal analysis is elaborated. The simulation results show that the spatial electrical operating points and the overall electrical power output of the module can be calculated from distributed parameters. The possibility of combining this modelling approach with physical characterisation techniques is discussed. This approach allows restoring PV modules utilizing material related parameters and acceleration over conventional methods, which may enable it to be a manufacturing relevant simulation tool.




Linearization of a one-diode PV model: (a) The circuit diagram with reference directions marked. (b) Linearization of the one-diode model according to a given operating voltage Vx. (c) The linearized one-diode model can be represented by a set of parallel connected equivalent linear conductance (Geq) and equivalent current source (Ieq)