Design, prototyping and validation of a wireless, self-powered, non-intrusive power consumption metering device for mains electricity in virtue of inductive energy harvesting techniques
Autor: Edgar Saavedra Darriba
Directora: Asunción Santamaría Galdón
This Master Thesis aims to offer an easy way for metering power consumption at electric lines without the need of encroaching electric installations. Since the main objective is providing a simple manner to monitor electric consumption remotely, the device proposed in this Master Thesis will be self- powered thank to inductive energy harvesting techniques —taking advantage of the magnetic fields inducted around the electric lines themselves. This yields to attaining a very low power consumption for the microcontroller and peripherals as well as a clever energy management system due to the energy harvested being extremely low.
First, a deep research on low power modes (LPM) for the microcontroller will be done to reach the lowest energy intake possible. This is a crucial factor in the project owing to the fact that the lower the consumption, the more flexibility on the design of the device. The microcontroller’s behaviour shall be in bursts as the energy available from the magnetic fields is not enough to drive a full processor continuously in time. This means an energy storage system will be required in sync with a dynamic firmware for the microcontroller.
For this reason, according to the available energy, the microcontroller must behave one way or another changing the period of measurements, the period of wireless transmissions, etc.
Second, several measures on how much energy will be available to harvest from the magnetic fields will be carried out to study the viability of the project. Taking for granted that this will be accomplished, the next stage is designing the power management and storage electronics in order to fulfil the microcontroller’s minimum power demand, as said before. This system will use a battery and a capacitor to manage the incoming power in the most effective manner. Also, it must be able to provide the microcontroller with enough power in compliance with its needs.
Finally, the proper firmware for the microcontroller will be developed in conformity with the available energy resources, as well as the wireless transmission protocol. This firmware must be able to handle the above-stated resources and change its behaviour automatically to satisfy the system constraints. It must ensure that the energy present in the storage element never drops to zero as the device might remain futile.
Carrying out all these stages and blending things together, a fully functioning, autonomous metering device will be ready to use. This development will keep track on power consumptions without the necessity of either altering current electric installations or deploying feeding and data lines for the metering devices themselves. This consumptions record can help us save energy by enhancing our habits at the same time that we are aiding the environment by reducing pollution.