Maximum power point tracking based on slidingmode control for output-series connected converters in photovoltaic systems

A perturb and observe algorithm based on both the power-current characteristic of a photovoltaic (PV) panel and the sliding-mode control of the input inductor current of an associated converter is investigated in a static application. A single ended primary inductance converter (SEPIC) converter charging a battery from a PV generator illustrates the procedure whose effectiveness is proved with experimental results. The reported technique is appropriate for distributed maximum power point tracking of PV systems with output series connected DC-DC switching converters. In these systems, each converter is supplied by an independent PV panel at the input port whereas its output port is connected in series with the output ports of the other converters. The proposed converter interconnection is based on a transformer-less SEPIC because of the capability of this converter to step-up or step-down the input voltage. The resulting system allows maximum power extraction from each PV source even in cases of non-uniform irradiance.