Abstract—In
the case of photovoltaic (PV) systems, an adequate PV voltage regulation is
fundamental in order to both maximize and limit the power. For this purpose, a
large input capacitor has traditionally been used. However, when reducing that
capacitor’s size, the nonlinearities of the PV array make the performance of
the voltage regulation become highly dependent on the operating point. This
paper analyzes the nonlinear characteristics of the PV generator and clearly
states their effect on the control of the dc/dc boost stage of commercial
converters by means of a linearization around the operating point. Then, it
proposes an adaptive control, which enables the use of a small input capacitor
preserving at the same time the performance of the original system with a large
capacitor. Experimental results are carried out for a commercial converter with
a 40 μF input capacitor, and a 4 kWPV array. The results corroborate the
theoretical analysis; they evidence the problems of the traditional control,
and validate the proposed control with such a small capacitor.
(Index
Terms—Adaptive control, photovoltaic converters, photovoltaic power systems,
small-signal modeling, voltage control.)
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