Modelling and analysis of multi-junction photovoltaic cells using MATLAB/Simulink for the improvement of conversion efficiency

Multijunction solar cells (MJSCs) are a more efficient photovoltaic solar cell technology than the conventional single junction alternative. When used in conjunction with concentrator technology MJSCs can provide conversion efficiencies upwards of 40% - due to a better conversion response to a broader light spectrum. Iterative design methodology can be applied to derive models of conversion efficiency in MJSCs by adapting existing single junction solar cell (SJSC) modelling practices. However this can be a very time consuming process, given the abundance of literature regarding conversion efficiency in SJSCs. This dissertation provides several criteria to consider when designing MJSC conversion efficiency models, by addressing two research questions: (1) how is the conversion efficiency of MJSCs simulated within the Matlab/Simulink environment?, (2) and which of the existing SJSC modelling practices are more/less adaptable for simulating MJSCs in the Simulink environment. The first part of the literature review outlines the peer reviewed literature regarding SJSC model practices and discusses the results of the project simulation tests. The second part of the review (1) outlines the literature on MJSC architecture related to model design, (2) proposes an iteration of a SJSC model that simulates the conversion efficiency in MJSCs and (3) discusses the results of the proposed model tested under Simulink simulation. The simulation results confirmed that, as expected, the double diode model provides more accurate results than the single diode model, with respect to changes in temperature and changes in irradiance. The simulation results confirmed that the proposed model correctly simulated the conversion efficiency in MJSCs with respect to irradiance, but failed to correctly simulate the conversion efficiency in MJSCs with respect to temperature. This paper offers insight into appropriate and inappropriate SJSC modelling techniques to consider when applying iterative design methodology to design a model that correctly simulates MJSC conversion efficiency within the Matlab/Simulink environment