A power electronic approach to improved dual-frequency vibration energy harvesting

Abstract

Vibration energy harvesters may be used as power sources for low-power, self-sufficient, wireless industrial sensors. State-of-the-art vibration energy harvesting uses switching power electronics to synthesize compact conjugate matched loads allowing for maximum harvested power. Previous work demonstrating dual-frequency vibration energy harvesting used a piezoelectric harvester loaded with analog-controlled power electronics but was unable to cancel the parasitic output capacitance typical of piezoelectric harvesters at both frequencies. This thesis addresses the technical challenge of achieving maximum power transfer from multi-frequency vibration energy sources, simultaneously. Improved dual-frequency energy harvesting is demonstrated using a piezoelectric vibration energy harvester loaded with digitally-controlled power electronics. The digital controller - performing fixed-point computations - allows for synthesis of a band-limited negative capacitor needed to improve dual-frequency energy harvesting.