Energy regeneration of an electrically interconnected suspension with various electrical network configurations under random or bump excitations

This paper studies a half-car suspension model equipped with two energy-harvesting shock absorbers (EHSAs) interconnected through a two-port electrical network. The network's impedance is modeled in the Laplace domain and then transformed into the time domain to augment the mechanical equations of motion. The coupled electromechanical system is analyzed in both frequency and time domains for three general circuit configurations: resistive, resistive-inductive, and resistive-capacitive. Power output is evaluated under two excitation scenarios: random and bump excitation. Under random excitation, power spectral density (PSD) analysis reveals that the resistive-capacitive network enhances low-frequency PSDs when internal EHSA impedance is present. However, due to a fast PSD roll-off at higher frequencies, the mean power does not improve significantly. Under bump excitation, the resistive-capacitive network exhibits improved performance—by approximately 5–6 percent —within the translational acceleration range of 4–10 m/s2 of the sprung mass. This improvement is attributed to the system's frequency response aligning with the dominant frequencies of the bump excitation, thereby enhancing energy regeneration.