| Abstract |
This paper shows that the efficiency of the Perturb
and Observe (P&O) Maximum Power Point Tracking (MPPT)
control technique can be improved by optimizing its sampling
interval Ta according to the converter’s dynamics. During
sunny days, when the maximum power point of the photovoltaic
(PV) array moves very slowly, the sampling interval Ta must be
set as short as possible without causing instability. If the
algorithm samples the array voltage and current too quickly, it
is subjected to possible mistakes caused by the transient
behavior of the PV array+converter system, thus missing
temporarily the MPP. As a consequence, the algorithm can be
confused, the energy efficiency decays, and the operating point
can become unstable, entering disordered behaviors. The
solution proposed in this paper lies in choosing Ta according to
the converter’s dynamics. The choice of the value of Ta
according to the proposed approach ensures a three-level
steady-state duty-cycle swing around the MPP, whatever the
duty-cycle step-size and the irradiance level are. As an example,
a boost MPPT battery charger has been studied. |
