Energy management and control of a standalone PV system using ultracapacitors

This paper presents the design and implementation of a standalone photovoltaic (PV) system using ultracapacitors as an energy storage unit. Ultracapacitors offer a high power density and long life cycle and could improve PV systems efficiency when subjected to peak loads. The setup is used to evaluate the direct parallel connection between the PV panel and the ultracapacitors bank without additional batteries. A buck-boost converter is interconnected between the ultracapacitors and to dc bus to match the voltage levels and allow the operation in buck and boost modes for charging and discharging the ultracapacitors respectively. The proposed energy management system is implemented on a 150W PV system prototype using a microcontroller. Simulation and experimental results for the buck mode of operation are used to demonstrate the feasibility and validity of the proposed approach.