Integration of supercapacitor in photovoltaic energy storage: Modelling and control

Due to the variable characteristics of photovoltaic energy production or the variation of the load, batteries used in storage systems renewable power can undergo many irregular cycles of charge / discharge. In turn, this can also have a detrimental effect on the life of the battery and can increase project costs. This paper presents an embedded energy share method between the energy storage system (battery) and the auxiliary energy storage system such as supercapacitors (SC). Supercapacitors are used to improve batteries life and reduce their stresses by providing or absorbing peaks currents as demanded by the load. The photovoltaic cells are connected to DC bus with boost converter and controlled with MPPT algorithm, Supercapacitors and batteries are linked to the DC bus through the buck-boost converter. The inductive load is connected to the DC bus by a DC-AC converter. The static converters associated with batteries and supercapacitors are controlled by current. The components of the systems are supervised through a block of energy management. The complete model of the system is implemented in MATLAB/Simulink environment. Simulation results are given to show the performance of the proposed control strategy, for the overall system.