Multiple-input multiple-output energy processing for energy-harvesting applications

This project belongs to energy harvesting field, which is a method of collecting energy from the environment to power small devices. This type of energy use is growing exponentially due to the appearance of many of these devices (sensors, wearables...). The objective of this project is to design and implement an ultra-low-power boost converter, designed for energy harvesting applications, which is able to add different types of energy coming from the environment to charge a battery or to feed another electronic device. It is a very innovative project and therefore, the methodology used has contemplated a lot of time for studying, doing simulations, optimizing and testing a prototype. This has allowed us to carry out a study of great value and usefulness which establishes the basis to construct a device that adds energies of our surroundings. Finally, to verify the feasibility of the application, a two-input boost converter is built to add energy coming from two different sources (with the possibility of expanding this number) and also offers different types of output storage elements. In conclusion, the work has confirmed the possibility of adding energy from our environment and has shown the great potential of the application studied through a functional prototype

Flexible Integration of Alternative Energy Sources for Autonomous Sensing

Recent developments in energy harvesting and autonomous sensing mean that it is now possible to power sensors solely from energy harvested from the environment. Clearly this is dependent on sufficient environmental energy being present. The range of feasible environments for operation can be extended by combining multiple energy sources on a sensor node. The effective monitoring of their energy resources is also important to deliver sustained and effective operation. This paper outlines the issues concerned with combining and managing multiple energy sources on sensor nodes. This problem is approached from both a hardware and embedded software viewpoint. A complete system is described in which energy is harvested from both light and vibration, stored in a common energy store, and interrogated and managed by the node

Switched Capacitor DC-DC Converter for Miniaturised Wearable Systems

Motivated by the demands of the integrated power system in the modern wearable electronics, this paper presents a new method of inductor-less switched-capacitor (SC) based DC-DC converter designed to produce two simultaneous boost and buck outputs by using a 4-phases logic switch mode regulation. While the existing SC converters missing their reconfigurability during needed spontaneous multi-outputs at the load ends, this work overcomes this limitation by being able to reconfigure higher gain mode at dual outputs. From an input voltage of 2.5 V, the proposed converter achieves step-up and step-down voltage conversions of 3.74 V and 1.233 V for Normal mode, and 4.872 V and 2.48 V for High mode, with the ripple variation of 20–60 mV. The proposed converter has been designed in a standard 0.35 μm CMOS technology and with conversion efficiencies up to 97–98% is in agreement with state-of-the-art SC converter designs. It produces the maximum load currents of 0.21 mA and 0.37 mA for Normal and High modes respectively. Due to the flexible gain accessibility and fast response time with only two clock cycles required for steady state outputs, this converter can be applicable for multi-function wearable devices, comprised of various integrated electronic modules

Energy Harvesting and Management for Wireless Autonomous Sensors

Wireless autonomous sensors that harvest ambient energy are attractive solutions, due to their convenience and economic benefits. A number of wireless autonomous sensor platforms which consume less than 100?W under duty-cycled operation are available. Energy harvesting technology (including photovoltaics, vibration harvesters, and thermoelectrics) can be used to power autonomous sensors. A developed system is presented that uses a photovoltaic module to efficiently charge a supercapacitor, which in turn provides energy to a microcontroller-based autonomous sensing platform. The embedded software on the node is structured around a framework in which equal precedent is given to each aspect of the sensor node through the inclusion of distinct software stacks for energy management and sensor processing. This promotes structured and modular design, allowing for efficient code reuse and encourages the standardisation of interchangeable protocols

Multiple-input multiple-output energy processing for energy-harvesting applications

This article deals with energy harvesting field, which is a method of collecting energy from the environment to power small devices. This type of energy use is growing exponentially due to the appearance of many of these devices. The objective is to design and implement an ultra-low-power boost converter, designed for energy harvesting applications, which is able to add different types of energy coming from the environment to charge a battery or to feed another electronic device. It is a very innovative project and therefore, the methodology used has contemplated a lot of time for studying, doing simulations, optimizing and testing a prototype. This has allowed us to carry out a study of great value and usefulness which establishes the basis to construct a device that adds energies of our surroundings. Finally, to verify the feasibility of the application, a two-input boost converter is built to add energy coming from two different sources (with the possibility of expanding this number) and also offers different types of output storage elements. In conclusion, the work has confirmed the possibility of adding energy from our environment and has shown the great potential of the application studied through a functional prototype.Postprint (published version

Design of Processing Circuitry for an RF Energy Harvester

Significant advancements in technology and the use of low power sensors in both commercial and industrial applications have made it essential to develop wireless solutions for low power devices. Once such solution, which has generated attention in university and R&D environments, is radio frequency (RF) energy harvesting. RF energy harvesting seeks to capture ambient RF energy by means of an antenna and convert this energy to useable DC power. The presence of ambient RF energy in the environment is a result of numerous high-frequency technologies including Wi-Fi, cell phones, microwave ovens, and radio broadcasting, as well as many others. The intention of this thesis is to design the processing circuitry necessary to convert a received RF signal into useable DC power, with the ability to charge a Lithium-Ion battery. The design presented here was performed to process an RF energy signal received from an antenna that targets both the 2.4GHz and 5GHz Wi-Fi bands. The final design consists of two bandpass filters (one for each Wi-FI band) two two-stage voltage doubler circuits (one for each Wi-Fi band), and a boost converter that is designed to achieve an output voltage of 3.2V in order to charge a Lithium-Ion battery. Testing of the RF energy harvester in an environment with ambient 2.4GHz Wi-Fi signals and a 470μF capacitor connected at the output demonstrates the circuit’s ability to harvest a measureable amount of energy. While the maximum measured voltage of 50mV does not meet the design specification of 3.2V, the circuit demonstrates proof-of-concept. Additional design improvements are necessary to make it a viable solution for charging a battery