Energy Harvesting for Self-Powered, Ultra-Low Power Microsystems with a Focus on Vibration-Based Electromechanical Conversion [open pdf - 2MB]
"Wireless distributed microsensor systems offer reliable monitoring and control of a myriad of applications ranging from machine state and perimeter security to nuclear/chemical/biological and other military applications. Historically, batteries have supplied power to mobile, embedded, and ultra-low power microsensors. While there are many obvious short-term advantages of using batteries, they do have a long-term negative environmental impact. An alternative to batteries exists in harnessing the ambient energy surrounding the system and subsequently converting it into electrical energy. Once a long-established concept, energy harvesting offers an inexhaustible replacement for batteries. Energy-harvesting systems scavenge power from optical, acoustic, thermal, and mechanical energy sources. The proliferation of and advances in wireless technology, particularly wireless sensor nodes and mobile electronic devices, has increased the volume of energy harvesting research as of late. This thesis reviews the principles of the state of the art in energy harvesting systems. We focus on generating electrical power from mechanical energy in a vibrating environment due to its dominant scalability. We explore microelectromechanical systems (MEMS), including electromagnetic, electrostatic, and piezoelectric transduction. Further, power management, trends, suitable applications, and possible future developments are discussed."
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