A new application of the coupled-inductors SEPIC converter to obtain I-V and P-V curves of photovoltaic modules

The achievement of I-V and P-V curves of photovoltaic modules gives the possibility to obtain the exact operation point, the short-circuit current (I_sc), the open-circuit voltage (V_oc), the maximum power point (MPP) and the fill factor (FF). These are significant parameters for the design and for the start-up of a photovoltaic installation. In this paper, we propose and analyse by means of simulation the capacity of the SEPIC (single-ended primary inductance converter) structure to implement I-V and P-V curves tracers of photovoltaic modules, mainly because the SEPIC topology presents the capability of buck-boost conversion. Thanks to this property, a complete sweep of the voltage and the current given by a photovoltaic panel can be made, including V_oc and I_sc . This structure is implemented by coupled inductors and presents two fundamental advantages: 1) it allows to emulate a resistance at the input converter within the range [0,infin) and 2) it guarantees a null ripple in the input current when the magnetic coupling of his two inductors fulfils ZRC (zero ripple condition)