A new control strategy for the optimization of Distributed MPPT in PV applications

• In DMPPT PV applications, the energetic efficiency depends on the several factors.
• In the mismatched PV systems, the joint adoption of the CMPPT and DMPPT techniques is necessary.
• A new control technique for the optimization of DMPPT is proposed.
• The first advantage of the proposed technique is the high speed of tracking.
• The second advantage of the proposed technique is the high energetic efficiency.

In this paper, a new control strategy allowing to optimize the performances of PV systems adopting Distributed Maximum Power Point Tracking (DMPPT) is presented and discussed. Such a strategy is based on the evaluation of an estimate of the optimal operating range of the inverter input voltage and on the evaluation of an estimate of the optimal operating voltages of the PV modules. The main advantage of the proposed technique is represented by the possibility to evaluate in closed-form the above estimates, provided that the PV modules short circuit currents are known. The closed-form evaluation of the above estimates allows in turn the fast identification of a set of optimal operating points for the inverter and for the PV modules; such a fast identification allows to obtain a marked increase of the speed of tracking of the maximum power point of the whole PV system. Moreover, a further advantage of the proposed technique is represented by the capability to avoid that the operating value of the inverter input voltage remains trapped in the neighborhood of a suboptimal operating point thus lowering the energetic efficiency of the PV system, as it may happen when standard MPPT techniques (such as the Perturb and Observe technique) are adopted.