Impact-driven, frequency up-converting coupled vibration energy harvesting device for lowfrequency operation

Abstract

This paper presents experiments and models of an energy harvesting device in which a lowfrequency resonator impacts a high frequency energy harvesting resonator, resulting inenergy harvesting predominantly at the system’s coupled vibration frequency. Analysisshows that a reduced mechanical damping ratio during coupled vibration enables increasedelectrical power generation as compared with conventional technology. Experimentsdemonstrate that the efficiency of electrical power transfer is significantly improved withthe coupled vibration approach. An average power output of 0.43 mW is achieved under0.4g acceleration at 8.2 Hz, corresponding to a power density of25.5 µW cm − 3. The measured power and power density at the resonant frequency are respectively 4.8times and 13 times the measured peak values for a conventional harvester created from alow frequency beam alone.