Fast-waking and low-voltage thermoelectric and photovoltaic CMOS chargers for energy-harvesting wireless microsensors

The small size of wireless microsystems allows them to be deployed within larger systems to sense and monitor various indicators throughout many applications. However, their small size restricts the amount of energy that can be stored in the system. Current microscale battery technologies do not store enough energy to power the microsystems for more than a few months without recharging. Harvesting ambient energy to replenish the on-board battery extend the lifetime of the microsystem. Although light and thermal energy are more practical in some applications than other forms of ambient energy, they nevertheless suffer from long energy droughts. Additionally, due to the very limited space available in the microsystem, the system cannot store enough energy to continue operation throughout these energy droughts. Therefore, the microsystem must reliably wake from these energy droughts, even if the on-board battery has been depleted. The challenge here is waking a microsystem directly from an ambient source transducer whose voltage and power levels are limited due to their small size. Starter circuits must be used to ensure the system wakes regardless of the state of charge of the energy storage device. The purpose of the presented research is to develop, design, simulate, fabricate, test and evaluate CMOS integrated circuits that can reliably wake from no energy conditions and quickly recharge a depleted battery. Since the battery is depleted during startup, the system must use the low voltage produced by the energy harvesting transducer to transfer energy. The presented system has the fastest normalized wake time while reusing the inductor already present in the battery charger for startup, therefore, minimizing the overall footprint of the system.Ph.D

Infrared Power Generation: Fundamental Understanding, Applications, and Benefits

The interaction between infrared radiation and a power generator device can be used to produce voltage and current. This phenomenon is called infrared power generation. It is shown that the infrared radiation transfers both thermal and electric energy to the power generator device. The coexistence of a thermal and an electrical component signifies that the temperature difference between the faces of the power generator devices is not a limiting factor to the amount of power that can be produced. Indeed, many avenues can be explored to increase the power for infrared energy harvesting purposes for military and civil applications. The existence of an electric component in the transferred energy also has interesting manifestations, such as the appearance of non-linear phenomena e.g. solitons, and fundamental consequences, which will be discussed

Battery-sourced switched-inductor multiple-output CMOS power-supply systems

Wireless microsystems add intelligence to larger systems by sensing, processing and transmitting information which can ultimately save energy and resources. Each function has their own power profile and supply level to maximize performance and save energy since they are powered by a small battery. Also, due to its small size, the battery has limited energy and therefore the power-supply system cannot consume much power. Switched-inductor converters are efficient across wide operating conditions but one fundamental challenge is integration because miniaturized dc-dc converters cannot afford to accommodate more than one off-chip power inductor. The objective of this research is to explore, develop, analyze, prototype, test, and evaluate how one switched inductor can derive power from a small battery to supply, regulate, and respond to several independent outputs reliably and accurately. Managing and stabilizing the feedback loops that supply several outputs at different voltages under diverse and dynamic loading conditions with one CMOS chip and one inductor is also challenging. Plus, since a single inductor cannot supply all outputs at once, steady-state ripples and load dumps produce cross-regulation effects that are difficult to manage and suppress. Additionally, as the battery depletes the power-supply system must be able to regulate both buck and boost voltages. The presented system can efficiently generate buck and boost voltages with the fastest response time while having a low silicon area consumption per output in a low-cost technology which can reduce the overall size and cost of the system.Ph.D

Contribution to the design and control of a hybrid renewable energy generation system based on reuse of electrical and electronics components for rural electrification in developing countries

While the Cambodia’s government is making effort to increase electricity production for its energy demand, it still remains dependent on the existing or the expansion of the centralized grid lines which have high initial investment cost. The temporally solution is to employ a distributed energy generation system which has lower life cycle cost and provides a diversity of technologies to meet the desired applications. Minimizing environmental impacts represents a major objective of sustainable development considering resources depletion and the limited capabilities of the environment to adapt. The potential of renewable energy resources has been well understood as the solutions to power rural development and to reduce the environmental impacts of energy generation. Due to advance in technologies and increasing consumer demands, there has been a vast amount of electrical and electronic waste which introduces severe impacts on the environment. The current strategies mainly rely on conventional waste collection and processing techniques for material recovery. This thesis proposed a solution of reusing discarded components in an isolated hybrid renewable energy system as the solution for electrification of rural Cambodia. This is frugal innovation, local solution with local materials for and with local people. A suitable configuration for the proposed system is a solar-hydro hybrid generation system since solar and water resources are plentiful in rural Cambodia. The components that are reused in the solution after being discarded include computer power supply units (PSUs) for the solar part, uninterruptable power supply units (UPSs) and three phase induction machines for the electrohydro part. Used auto-mobile batteries will be used for the system storage. The thesis presents in the first part the evaluation of the environmental impacts of the proposed reuse solution for rural electrification. The study of the environmental impacts is based on Life Cycle Assessment (LCA) methodology which compares the life cycle impacts of the proposed solution to that of a conventional solution. Moreover, a sensitivity analysis is achieved in order to evaluate the impacts of uncertainties of the environmental impacts. The second part of this work deals with the technological aspects of the reuse solution in both theory and experimentation. The first part of this aspect is focused on the repurposing of used computer power supply units (PSUs), through limited modifications of the circuits in order to increase its range of operation. The PSU which usually contains one of a few types of isolated DC-DC converters is repurposed as charge controller with MPPT control in a cheap micro-controller with very good results. The last part of this thesis studies a new configuration of generators based on re-used three-phase induction motors. The proposed single-phase generator is based on a three-phase machine in a modified version of the coupling and with a rather uncommon supply. Modelling is highly investigated. An inverterassisted topology where two windings will be supplied separately by two inverters for excitation and the remaining winding is connected to load. A new modeling of the generator has been studied. The results of simulation were compared to experimental test results in open loop study. These results have demonstrated the advantages of the new configuration in comparison to the previously proposed inverter-assisted topology in term of efficiency and minimization of torquerippl

Battery Management in Electric Vehicles: Current Status and Future Trends

Lithium-ion batteries are an indispensable component of the global transition to zero-carbon energy and are instrumental in achieving COP26's objective of attaining global net-zero emissions by the mid-century. However, their rapid expansion comes with significant challenges. The continuous demand for lithium-ion batteries in electric vehicles (EVs) is expected to raise global environmental and supply chain concerns, given that the critical materials required for their production are finite and predominantly mined in limited regions worldwide. Consequently, significant battery waste management will eventually become necessary. By implementing appropriate and enhanced battery management techniques in electric vehicles, the performance of batteries can be improved, their lifespan extended, secondary uses enabled, and the recycling and reuse of EV batteries promoted, thereby mitigating global environmental and supply chain concerns. Therefore, this reprint was crafted to update the scientific community on recent advancements and future trajectories in battery management for electric vehicles. The content of this reprint spans a spectrum of EV battery advancements, ranging from fundamental battery studies to the utilization of neural network modeling and machine learning to optimize battery performance, enhance efficiency, and ensure prolonged lifespan

Resilient and Real-time Control for the Optimum Management of Hybrid Energy Storage Systems with Distributed Dynamic Demands

A continuous increase in demands from the utility grid and traction applications have steered public attention toward the integration of energy storage (ES) and hybrid ES (HESS) solutions. Modern technologies are no longer limited to batteries, but can include supercapacitors (SC) and flywheel electromechanical ES well. However, insufficient control and algorithms to monitor these devices can result in a wide range of operational issues. A modern day control platform must have a deep understanding of the source. In this dissertation, specialized modular Energy Storage Management Controllers (ESMC) were developed to interface with a variety of ES devices. The EMSC provides the capability to individually monitor and control a wide range of different ES, enabling the extraction of an ES module within a series array to charge or conduct maintenance, while remaining storage can still function to serve a demand. Enhancements and testing of the ESMC are explored in not only interfacing of multiple ES and HESS, but also as a platform to improve management algorithms. There is an imperative need to provide a bridge between the depth of the electrochemical physics of the battery and the power engineering sector, a feat which was accomplished over the course of this work. First, the ESMC was tested on a lead acid battery array to verify its capabilities. Next, physics-based models of lead acid and lithium ion batteries lead to the improvement of both online battery management and established multiple metrics to assess their lifetime, or state of health. Three unique HESS were then tested and evaluated for different applications and purposes. First, a hybrid battery and SC HESS was designed and tested for shipboard power systems. Next, a lithium ion battery and SC HESS was utilized for an electric vehicle application, with the goal to reduce cycling on the battery. Finally, a lead acid battery and flywheel ES HESS was analyzed for how the inclusion of a battery can provide a dramatic improvement in the power quality versus flywheel ES alone

Innovative Technologies and Services for Smart Cities

A smart city is a modern technology-driven urban area which uses sensing devices, information, and communication technology connected to the internet of things (IoTs) for the optimum and efficient utilization of infrastructures and services with the goal of improving the living conditions of citizens. Increasing populations, lower budgets, limited resources, and compatibility of the upgraded technologies are some of the few problems affecting the implementation of smart cities. Hence, there is continuous advancement regarding technologies for the implementation of smart cities. The aim of this Special Issue is to report on the design and development of integrated/smart sensors, a universal interfacing platform, along with the IoT framework, extending it to next-generation communication networks for monitoring parameters of interest with the goal of achieving smart cities. The proposed universal interfacing platform with the IoT framework will solve many challenging issues and significantly boost the growth of IoT-related applications, not just in the environmental monitoring domain but in the other key areas, such as smart home, assistive technology for the elderly care, smart city with smart waste management, smart E-metering, smart water supply, intelligent traffic control, smart grid, remote healthcare applications, etc., signifying benefits for all countries

Recent Development of Hybrid Renewable Energy Systems

Abstract: The use of renewable energies continues to increase. However, the energy obtained from renewable resources is variable over time. The amount of energy produced from the renewable energy sources (RES) over time depends on the meteorological conditions of the region chosen, the season, the relief, etc. So, variable power and nonguaranteed energy produced by renewable sources implies intermittence of the grid. The key lies in supply sources integrated to a hybrid system (HS)