Design and analysis of a novel electromagnetic vibrational energy harvester with triangular structure

The energy harvesting from vibrations that are ubiquitous in the environment is the focus and hotspot of current research. In the paper, an electromagnetic vibrational energy harvester based on a triangular displacement amplification structure was proposed, which amplified the relative displacement between the magnet and the coil through a lever structure and improved the effect of vibration energy conversion. Springs were set at the ends of the levers to form a three-degree-of-freedom nonlinear dynamic system, which broadened the energy harvesting frequency bands of the system. Using the Runge-Kutta method, the dynamic response of the system was numerically analyzed. The results show that the designed system has two energy harvesting frequency bands, one of which covers the low frequency range below 5-10 Hz, and the other covers the 20-45 Hz frequency band. By analyzing the influences of different design parameters on the vibration energy harvesting effect, it is found that increasing the assembly angle of the lever structure, the mass of the lower slider and the spring stiffness is beneficial to energy harvesting in the low frequency range, while reducing the assembly angle and slider mass can improve the output voltage of the second acquisition frequency band. Comparing the designed system with the equivalent linear vibration energy harvester, it is found that thanks to the displacement amplification effect of the levers, the maximum output voltage of the triangular vibration energy harvester under the same excitation is 1.76 times that of the linear vertical vibration energy harvesting system. These characteristics make this new type of harvester able to achieve good energy harvesting effect for low-frequency and wide-range environmental vibrations. © 2021, Editorial Office of Journal of Vibration and Shock. All right reserved.