A multivariable MPPT algorithm for granular control of photovoltaic systems

In this paper a novel approach to the Maximum Power Point Tracking (MPPT) in distributed PhotoVoltaic (PV) applications is proposed. It is useful when the granular control of the PV field is applied by adopting a dc/dc converter for each PV module. It consists of a single digital controller implementing a multivariable MPPT algorithm based on the Perturb and Observe (P&O) approach, acting on the dc/dc converters dedicated to each PV module and with their output terminals put in series connection. The control strategy only requires a single current sensor on the dc bus, so that classical PV modules current sensing is avoided. PSIM simulations confirm the advantages offered by the proposed approach.