A Comparative Study of Flexible Power Point Tracking Algorithms in Photovoltaic Systems

The ever-increasing penetration of photovoltaic power plants (PVPPs) in the power system and the need for voltage control and frequency support services impose new requirements on PVPPs, extending the functionalities of existing maximum power point tracking (MPPT) algorithms. Accordingly, a considerable number of flexible power point tracking (FPPT) algorithms are introduced in the literature. The aim of such algorithms is to regulate the PV power to a specific value rather than continuously track the maximum power point. This power reference value is calculated based on the operation condition and grid requirements. This paper provides a short description of several available FPPT algorithms in the literature, and studies various features of each algorithm. The dynamic performance of the investigated algorithms is compared using experimental tests on a scaled-down prototype. The comparison reveals that the FPPT algorithms with direct calculation of the voltage reference, which corresponds to the required power reference, provide better performance in all aspects.