A 1-mW vibration energy harvesting system for moth flight-control applications

Abstract

This thesis focuses on the approach and methodologies required to build a 1-mW energy-harvesting system for moth flight control applications. The crepuscular hawk moth Manduca sexta is the chosen test subject. This project is part of the Hybrid Insect MEMS (HI-MEMS) program. The objective of the program is to establish an interface between adult insect neural systems, wireless communication and MEMS systems so that insects may be directed to fly to specific locations in real time. As in all micro-air vehicles, power is one of the major concerns. A power source on the moth is required to support the flight control and wireless communication systems. There are two methods by which these payloads might be powered. The first method is to draw power from a battery, while the second method is to harvest energy from the environment. Batteries have the advantage of simplicity, while energy harvesting systems have much longer life and lower mass per total energy delivered. In addition, the total mass of circuitry, MEMS devices, and batteries may severely limit flight duration. Therefore, we have chosen the energy-harvesting method. The energy harvesting system includes a vibration energy harvester and a boost converter that delivers power at the required 1-V level for the entire flight control system.

(cont.) The latest harvester has a mass of 1.28 g and output power of 1.7 mW into a matched resistive load when the moth vibrates with a +0.37-mm amplitude at 25.8 Hz, resulting in a ±7.82-mm harvester amplitude. A 2-stage AC-DC boost converter with off chip inductors has been designed and fabricated in 0.18 um CMOS technology. SPICE simulation and experiments using equivalent discrete components prove that the converter can achieve 71.68% efficiency. The test experiment of the chip will be conducted later this winter and is not included in the scope of this thesis.