Concepção de um circuito energy harvesting aplicado a redes de sensores sem fio para sistemas de iluminação

Abstract

This thesis aims to present the design and development of an Energy Harvesting (EH) circuit applied to wireless sensor networks (WSN), especially those that perform functions in lighting systems, such as monitoring or control. The primary function of an Energy Harvesting system is to convert, condition and manage energy from an available source in the environment, in order to power low power consumption devices, which usually would be fed by batteries. The most used energy sources in EH systems are solar, wind, electromagnetic waves, mechanical vibration and thermal differences. Thus Energy Harvesting is an alternative to increase the autonomy or even eliminate the use of batteries for portable, implanted or remote located devices. Initially, an analysis of the most appropriate energy sources to power wireless sensors networks is performed, taking into aspects such as energy density, advantages and disadvantages. Subsequently, the proposed EH circuit is developed and tested. One of the specific objectives is that the EH proposed circuit is capable to being adapted for different energy sources. The proposed circuit consists of two stages, the first is a pre-amplifier and rectifier based on Villard multiplier. The second stage consists of a low-power boost converter with a synthesized inductor. The circuit is able to operate with minimum input voltages about 0.3 V, reaching maximum output of 5 V and 100mW of power.