Passive Mechanical Switching for Synchrony-Free Integration of Footstep Energy Harvesters

Footstep energy harvesters can convert pedestrian kinetic energy into electrical power for electronic devices and have undergone significant advancements as an emerging alternative to conventional dry batteries. Typically, these harvesters are connected in specific configurations to form an array that supplies power to a single electronic device. However, conventional combination methods, such as series and parallel configurations, result in energy losses and exhibit low fault tolerance. Integrating active control modules into the energy harvesting circuit presents a feasible solution but introduces additional energy consumption. This work proposed a novel passive mechanical switching method for footstep energy harvester array, where pedestrian movement dynamically adjusted the states of specific mechanical switches within the array, enabling precise control over the target circuit branches. Test results indicate that compared to the conventional series combination method, the proposed method can bring a 31.07% increase in load voltage when applied a footstep on the first harvester in the array with step velocity of 0.5 cm/s, and can increase the effective operating time of the load by 282% when applied footsteps to the harvesters in sequence with step velocity of 1 cm/s. The proposed method demonstrates its contribution in improving energy conversion efficiency and potential for large-scale application value.