The objective of this research is to explore innovative ways to increase the energy conversion efficiency and address the issues limiting wide-spread usage of electromagnetic transduction for harvesting vibration energy. Specifically studied are the methods to increase the conversion efficiency through ingenious designs and fabrication techniques, implement high-energy-conversion ideas with macro- and micro-fabrication technologies including microfabrication processes for permanent magnets and low resistive coils, and demonstrate low-cost energy harvesters with unprecedented conversion efficiency and power level. The intellectual merit is in the new electromagnetic energy-conversion principle based on arrays of magnets and coils with a magnet array moving in parallel with a coil array in response to vibration input. The new conversion principle has resulted in 270 mW power (into 96 ohm load) out of 0.66 mm vibration amplitude at 65 Hz with a harvester occupying 26 cc and weighing 90 gram. Such a large power is unprecedented, and this research is transformative as it enables hand-held harvesters to be capable of generating 1 100 W out of sub-millimeter vibration amplitude as well as microfabricated counterparts capable of 1 1,000 mW. The broader impacts are on harvesting ubiquitous vibration energy for alternative energy means and micropower source for electronic or electromechanical systems (removing the need of battery). Students from underrepresented groups including local inner-city high school students will be given opportunities to work on the proposed research. Moreover, local inner-city high schools will be offered working energy harvesters with which the high school students can experiment in their science labs.
