Vibration energy harvesting based on a piezoelectric nonlinear energy sink with synchronized charge extraction interface circuit

Nonlinear energy sink (NES) conventionally designed for vibration control has been recently explored for energy harvesting purpose. To simplify the analysis, a pure resistive load is usually used in the evaluation of the performance of NES-based energy harvesting systems. This paper investigates the performance of an NES-based energy harvesting system interfaced to a synchronized charge extraction (SCE) circuit (EHNES-SCE). For the ease of analysis, the SCE interface circuit is simplified by the equivalent impedance method. An equivalent circuit model for system-level simulation of the EHNES-SCE system is also established to confirm the feasibility of using the simplified SCE circuit. Subsequently, with the simplified SCE circuit, approximate analytical solutions of the EHNES-SCE system are derived using the harmonic balance method and the performance of the EHNES-SCE system under harmonic excitation is investigated. With the established modelling and simulation tools, the influences of electrical load and electromechanical coupling on the performance of the EHNES-SCE system are revealed. Finally, experimental results are presented to confirm the main findings from the theory and simulation and reveal that the EHNES-SCE system is able to harvest energy in a wide frequency range, regardless of the load resistance in the SCE circuit. (paper)