Vehicle-Level Modelling and Analysis of Onboard Energy Harvesters and Their Impact on Dynamics

Integrating energy harvesters into rail transit systems, such as vehicles, offers a sustainable power solution for onboard sensors, yet their impact on vehicle dynamics remains largely underexplored. This study proposes an approach that combines vehicle dynamics, energy harvesters, and interface circuits to thoroughly analyze bidirectional complex coupling effects between the subsystems. An equivalent circuit model (ECM) is developed by employing the mechanical-electrical analogy theory to simulate vehicle dynamics, and its accuracy is verified through comparison with a traditional dynamic model. Subsequently, electromagnetic and piezoelectric harvesters were integrated into the model, along with power-boosting interface circuits, to assess the combined effects. The energy harvesting performance and the vehicle dynamic behaviors under harmonic and random excitations were investigated. Results indicated that the power-boosting interface circuits can significantly enhance energy harvesting efficiency and stabilize power output under different excitation conditions. However, the installation of energy harvesters deteriorates vehicle dynamics noticeably, and the power-boosting interface circuits further exacerbate these effects, particularly at low frequencies. In general, the proposed ECM presents a comprehensive method for the design and optimization of onboard energy harvesters and their interface circuits, offering insights from a system-level analysis for rail transit applications.