Cadmium Telluride Solar Cell: From Device Modeling to Battery Charging Application through Maximum Power Point Tracking and Charging Circuitry

摘要

Battery charging for industrial and vehicular application by second generation thin film solar cells like CdTe can have a promising future for their cheaper production and better efficiency. Though the production of solar cells is still based mainly on silicon (Si), the market share of thin film solar has been increasing over the last few years. The mathematical modeling of the voltage dependent current-voltage (I-V) characteristics of Cadmium Telluride (CdS/CdTe) Solar cell and utilizing the model as an electrical source to charge a Li-ion battery and to charge it a battery charging algorithm in a concept level has been analyzed in this thesis. A single cell is developed based on the mathematical model and a solar module/network is constructed considering a series and parallel combinations of the single cell. The module performance is analyzed from efficient circuit operating viewpoint under various operating conditions. To extract the power from the solar cell, Perturb and Observe (P&O) Maximum power point technique has been used. Battery charging with its charging algorithm is also discussed in this paper. To apply the power as charging source after P&O converter a second dc-dc converter driven with a battery charging algorithm is applied to charge a Li-ion battery. A simple charging algorithm considering both constant current and constant voltage mode charging system has been developed. Both CC and CV mode and algorithm switching between these two modes developed here has shown a consistent result in battery charging simulation.