Design of a frequency-adjusting device for harvesting energy from a rotating wheel

This study designed a well-weighted pendulum to harvest energy from a rotating wheel, which consisted of a pendulum and one or more weights. In general, a pendulum cannot oscillate with a large angle at any wheel speed. In this study, three well-designed weights helped the pendulum to adjust its natural frequency to meet the wheel rotation frequency. Therefore, the well-weighted pendulum is able to oscillate at various wheel speeds with a large angle and a high velocity. The kinetic energy produced was converted into electrical energy by electromagnetic induction, and a numerical study revealed that the well-weighted pendulum generated a power of several milli-Watts. The numerical results obtained using the analytical model of the well-weighted pendulum were in good agreement with the experimental results. The swing angle of the weighted pendulum was close to 43° at a wheel rotation speed of 350 rpm, 8 times that of the ill-weighted pendulum, verifying that the well-weighted pendulum oscillated at larger angles.