PhD Final Defense by Sehwan Kim

Energy Harvesting and Power Optimization for Remote Sensing Systems by Sehwan Kim Location: Engineering Gateway РCEE Conference Room Date and Time: October 27, 2011 2:00pm Committee: Prof. Pai Chou (Chair) Prof. Masanobu Shinozuka Prof. Maria Feng Abstract: The mobile and wireless micro-sensors suffer from short operational lifetimes because they lack space to store the energy that wireless transmission, signal conditioning, and monitoring require to operate across time. Energy harvesting capabilities enable totally untethered operation of mobile and wireless micro-sensors for extended periods of time without requiring battery replacement. This paper is to introduce and discuss the design challenges associated with harvesting circuits when harnessing, conditioning, and transferring power from ambient energy sources. In addition, supercapacitors have emerged as an increasingly viable alternative to batteries for micro-solar energy harvesters. To address the problems of high leakage and high unusable residual charge, previous work proposed multiple supercapacitors with a reconfigurable topology. We propose to optimize such systems by two ways: selection of optimal sizes of the supercapacitors at design time, and choosing the optimal series or parallel topology at run time. This combination enables the supercapacitor subsystem to maximize the energy storage while minimizing leakage and residual energy, thereby enabling the maximum utility of the energy storage elements over different operating scenarios.