Programmable energy source emulator for photovoltaic panels considering partial shadow effect

The aim of this paper is to study and produce a programmable emulator for photovoltaic panels. A uniform solar illumination model, a partially shaded model with two photovoltaic modules in series and a partially shaded model with two photovoltaic modules in parallel are proposed in this paper. Solar illumination and ambient temperature can be set on the emulator to emulate the behavior of a photovoltaic panel and to explore the effect of its being polluted by dust, shaded by clouds or solar oblique incidence. When making the physical models, a digital signal processor is used to calculate the quiescent points of the photovoltaic panels according to the load resistance and characteristics of the photovoltaic panels, and a DC (direct current)/DC buck power converter is adopted to adjust the output of the emulator in accordance with the quiescent points. To reduce the DSP's (digital signal processor) calculation burden, a characteristic curve segmentation method is proposed. This study successfully develops a 300 W/60 V emulator for photovoltaic panels under uniform solar illumination and partially shaded conditions. The load is changed over and over again so as to sketch the V–P curve and confirm the feasibility of the emulator.