Efficiency and effectiveness of stabilization control of high-energy orbit for wideband piezoelectric vibration energy harvesting

摘要

This paper investigates the efficiency and the effectiveness of the stabilization control which makes the highest-energy steady-state solution of a nonlinear wideband piezoelectric vibration energy harvester globally stable. For the conventional linear vibration energy harvester, there is a trade-off between the bandwidth of the resonance peak and the performance of the power generation in the resonance frequency band. A nonlinear harvester can expand the resonance frequency band to generate larger electric power in a wider frequency range. However, since the nonlinear oscillator can have multiple stable steady-state solutions in the resonance band, it is difficult for the nonlinear vibration energy harvester to maintain the response in the highest-energy solution under the presence of disturbances. A self-excitation circuit has been proposed to make it possible to stabilize the highest-energy solution globally for a nonlinear piezoelectric vibration energy harvester. The self-excitation circuit consists of a switch that connects/disconnects the load circuit and a positive velocity feedback circuit. This circuit can destabilize other unexpected lower-energy solutions and entrain the oscillator only in the highest-energy solution by providing electric energy to the piezoelectric elements. In this study, numerical analyses and experiments are conducted to show that the proposed self-excitation control can provide the global stability to the high-energy solution and maintain the performance of the power generation in the widened resonance frequency band. Furthermore, the energy consumption by the self-excitation circuit is evaluated by numerical analyses in order to find more efficient control law to realize the self-powered control circuit.