Pendulum energy harvester with torsion spring mechanical energy storage regulator

This paper presents the integration of a novel mechanical torsion spring regulator into a pendulum energy harvester system. This regulator was designed to provide the same voltage-smoothing benefits of a flywheel without the start-up issues caused by increasing system inertia. In addition, the introduction of the spring between the input and output stages of the device acts as a buffer for any sudden impacts, which not only allows the energy from such events to be fully absorbed and dissipated slowly through the output but significantly reduces the torque stress and torque fluctuation stress on critical components to improve the reliability of the system. Through experimentation and simulation, the transducer was shown to reduce the voltage fluctuation range from 13.85 to 28.16 V to 16.41 to 23.59 V for the pendulum energy harvester at resonance, and comparison of start-up response to that of a device with a flywheel shows a significant improvement in initial acceleration of the output when subjected to excitation. The energy harvester with spring has demonstrated a maximum normalised average power output of 12.09 W/g², a maximum normalised average voltage of 109.96 V/g, and a maximum normalised power density of 7.8 W/g²/kg, at a resonant frequency of 1.2 Hz. The effectiveness of the spring mechanism for regulating output voltage and power, improving start-up performance, and reducing stress on critical components has significant implications for the real-world viability of pendulum energy harvesters, with the potential to improve their reliability in often unpredictable environments.