A wireless irradiance-temperature-humidity sensor for photovoltaic plant monitoring applications

In this paper we present the project and a first concept circuit of a wireless sensor station designed to collect and send information about the environment conditions of a photovoltaic (PV) power plant, in order to monitor on-site specific phenomena of interest. The system is battery-free and uses a 4 mm² PV harvester chip as electronic supply. It is equipped with temperature, irradiance and humidity sensors and with a MicroController Unit (MCU) for data treatment and wireless management. The light irradiance sensor discriminates the contribute of direct and diffusive light, accounting for air mass index effects. The PV harvester is integrated using a 0.35 μm BCD SOI technology while sensors, the MCU and a 802.15.4 transmitting module are placed in a external Printed Circuit Board (PCB). The goal of this project is to realize a 1 cm² autonomous fully-integrated device representing the single low-cost node of a Wireless Sensor Network (WSN) to be installed in each PV module of a solar power plant.