Research on Energy Harvester for Low Frequency Vibration Based on Inertial Rotary Structure

Some common vibration sources in our ambient environment are sampled and their spectrum are analyzed. The results show that low-frequency vibration sources are widely distributed and typically have large vibration acceleration, which means they are an ideal energy source for vibration energy harvesting. For low-frequency vibration sources, an energy harvester based on an inertial rotary structure is proposed, which can transfer linear motion to high-speed inertial rotary movement, and its operating principle and dynamic model are also analyzed in detail. The experimental results indicate that the energy harvester can collect 85.2 mJ of energy from one step of an adult, and the instantaneous output power can reach up to 32.2 mW. Through continuously collecting the energy generated by human walking, the energy harvester can successfully drive a wireless sensor health monitoring system to operate normally. Furthermore, by optimizing the device size and structure, the energy harvester can also be applied to collect ocean wave energy with 112.2 mW of average output power and 58.87 μW/cm³ of power density. The effects of device structure parameters and external excitation conditions on the output are also explored.