PFC Control Signal Driven MPPT Technique for Grid-Connected PV Systems

In this article, a novel MPPT technique is proposed and experimentally tested. It is called 'grid-connected photovoltaic (PV) systems maximum power point tracking (MPPT) technique driven by the power factor correction (PFC) controller' (CICERONE). It generates, for both single stage (SS) and double stage (DS) grid-connected PV systems, the bulk voltage reference by exploiting only the internal (not coming from sensors) PFC control signal. CICERONE leads to a piecewise ramp bulk voltage whose slope is updated to maximize the average power injected into the grid. Experimental results show that CICERONE exhibits better performance and robustness than the Perturb and Observe MPPT technique, especially in case of dynamic irradiance conditions. In addition, CICERONE can be applied without modifications to both SS and DS grid-connected PV systems. Hence, differently from a traditional DS system, in a CICERONE based DS system, the dc-dc converter can be operated with a fixed duty-cycle and can work in the highest efficiency conditions. Moreover, CICERONE operates without using external signals coming from sensors and affected by measuring noise (such as PV voltage, PV current, grid current, or their derivatives), but it performs the MPPT using only an internal signal already used for PFC purposes.