Indoor power harvesting using photovoltaic cells for low power applications

Utilization of low power indoor devices such as remote sensors, supervisory and alarm systems, distributed controls, and data transfer system are on steady rise. Due to remote and distributed nature of these systems, it is attractive to avoid using electrical wiring to supply power to them. Primary batteries have been used for this application for many years but they require regular maintenance at usually hard to access places. This paper provides a complete analysis of a PV harvesting system for indoor low power applications. The characteristics of a target load, photovoltaic (PV) cell and power conditioning circuit are discussed. Different choices of energy storage are also explained. Implementation and test results of the system are presented that highlights the practical issues and limitations of the system.