Solar PV based retrofit solution for cell phone towers powered by diesel generators

The use of cellular phones and hence its infrastructure has been growing very rapidly across the globe. The power system for a cell phone tower needs uninterrupted power supply. Hence its power system relies heavily on batteries and Diesel Generator (DG) sets - especially at those places that do not have a regular power grid. The batteries need heavy maintenance and do not work well at high temperatures. They also have a short life span. In this paper, a PV based system solution is proposed which can be retrofitted in the existing power system of the cell phone towers. This solution makes use of ultracapacitors and reduces the use of batteries. The implemented control scheme facilitates MPPT of the PV source, easy integration of the ultracapacitor stack into the system and seamless transition from grid-tied mode to islanded mode and vice versa. Mathematical modeling and system design for a 3kW cell tower power system are presented. The model is validated using simulation results. All the results of this work are presented.