Date of Thesis

Spring 2024

Description

Microgrids are localized, independent power grids that can operate while connected to the larger electrical grid. These systems make intelligent decisions regarding power management and use an array of components to monitor power generation, consumption, and environmental conditions. While this technology can save end users money, the complexity of installation and maintenance has limited the adoption of microgrids in residential spaces. To simplify this technology for end users, the next evolution of microgrid components includes sensors that are wireless and ambiently powered.

Even with a microgrid installed, significant energy is wasted in residential spaces. To address this loss, energy harvesting circuits can be incorporated into microgrid sensors, enabling them to recapture otherwise wasted environmental energy. Light, heat, radio frequency (RF) energy, mechanical energy, and 60 Hz noise from power lines are all abundant in most residential spaces and can be harvested to power microgrid components. Equipping microgrid sensors with energy harvesters simplifies the end user experience by eliminating the need for cable routing. Implementing energy harvesting techniques results in a microgrid that is easier to deploy, cleaner, and requires less maintenance.

Developing this type of sensor is not only feasible, but sensible and can be constructed using off-the-shelf components. My research led me to conclude that the most effective strategy for designing an energy harvesting sensor is to combine energy harvesting technologies with battery power. By delegating smaller loads away from the harvesting integrated circuit (IC), its full harvesting potential is utilized, maximizing energy collection for the power-hungry transmitter. Simultaneously, a small coin-cell battery can sustain the remaining components, ensuring over a decade of functionality. This thesis explores the feasibility and design of a hybrid battery and energy harvesting sensor. The developed system block diagram allows for the swapping of components within each block, catering to the varying needs of the end user. The system is data and energy-aware, allowing it to make intelligent decisions regarding data transmission and enable communication as reliable as that of a traditional wire-line powered sensor.

The hybrid sensor module underwent testing with a small monocrystalline solar cell as its energy source, delivering consistent power throughout the testing period. It accumulated surplus energy in a super capacitor storage unit, ensuring the system’s reliable operation even at night when the energy source was not available. While the tests utilized a photovoltaic (PV) cell, the design accommodates any energy harvesting source that can generate a minimum of 40 µW of power.

Keywords

energy harvesting, residential microgrid, home energy management, sensors, smart grid, hybrid sensors

Access Type

Masters Thesis

Degree Type

Master of Science in Electrical Engineering

Major

Electrical Engineering

First Advisor

Peter Mark Jansson

Second Advisor

Stewart J. Thomas

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