Equivalent circuit modeling for triboelectric energy harvesters

The utilization of triboelectric transduction for vibration energy harvesting has garnered considerable attention owing to its manifold advantages. Researchers across diverse disciplines have endeavored to develop various theoretical models to investigate the properties of triboelectric energy harvesters (TEHs). Initially, material scientists formulated analytical models to explain triboelectric transduction's electric energy generation process. Subsequently, experts in mechanical engineering devised dynamical models to describe the mechanical response of TEHs, often simplifying the energy extraction circuit (EEC) to a mere resistor. Conversely, researchers in electrical engineering derived models for intricate EECs but tended to oversimplify the harvesters’ mechanical response as sinusoidal motions. Consequently, the integration of models addressing both the electromechanical response of the harvesters and the practical EECs remains largely unaddressed due to the analytical challenges posed by such intricate systems. This article presents a novel technique to reconcile the disparity between the electromechanical and EEC models of TEHs by implementing an equivalent circuit model (ECM). Initially, the equivalent circuit parameters of the harvester are identified based on an electromechanical model of a cantilever-based harvester. Subsequently, an ECM encompassing both the mechanical and electrical responses is established. Finally, the ECM is experimentally validated, demonstrating its capability to simulate the harvester's performance on a holistic system level. This proposed methodology serves as a crucial step towards comprehensive modeling and optimization of TEH systems for enhanced energy harvesting efficiency and applicability in various domains.