Analysis and Characterization of Optimized Dual-Frequency Vibration Energy Harvesters for Low-Power Industrial Applications

We present a multiresonant vibration energy harvester designed for ultra-low-power applications in industrial environments together with an optimized harvester design. The proposed device features dual-frequency operation, enabling the harvesting of energy over a wider operational frequency range. It has been designed such that its harvesting bandwidth range is [50, 100] Hz, which is a typical frequency range for vibrations found in industrial applications. At an excitation level of 0.5 g, a maximum mean power output of 6 mW and 9 mW can be expected at the resonance frequencies of 63.3 and 76.4 Hz, respectively. The harvester delivers a power density of 492 µW/cm(2). Design optimization led to improved harvester geometries yielding up to 2.6 times closer resonance frequencies, resulting in a wider harvesting bandwidth and a significantly higher power output.