Combination of Distributed MPPT and Distributed Supercapacitor Energy Storage Based on Cascaded Converter in Photovoltaic Installation

This paper presents a proposal for a new architecture of a stand-alone/grid-connection small photovoltaic (PV) installation based on a cascaded half-bridge DC-DC converter. Cascaded configuration provides distributed maximum power point tracking (MPPT), which increase power generation, but is more complex and more expensive. Furthermore, boost topology of DC-DC converters in cascaded configuration does not efficient works in the cases of mismatch in solar panels conditioned of the different types of PV panels, they partial shading, aging, or manufacturing variation. We propose to introduce in each a channel of cascaded DC-DC converter a supercapacitor (SC) pack combining distributed MPPT with distributed energy storage. Setting the SC pack in each a channel between the PV panel and the DC-DC converter enables using of SC pack for simple MPPT control and simultaneously power decoupling of energy generation stage from energy consumption. The latter allows improving distributed control of DC-DC boost converters in cascade with series connected outputs. To control of proposed PV installation,it has been developed some control subsystems: searching MPPT with one current sensor, flatness interleaving control of DC-bus voltage, balancing of SC voltages, energy management system (EMS). The conducted simulation studies in the Matlab/Simulink environment showed the workability and effectiveness of the proposed solution.