Optimal design of a piezoelectric coupled beam for power harvesting

An optimal design of a beam structure coupled with a piezoelectric patch is developed to achieve high efficiency of power transformation from a mechanical input to an electrical output power for the application of power harvesting. The power harvesting is realized by generating an electric voltage from the electromechanical coupling effect by the piezoelectric patch when the host beam is subjected to a dynamic loading. The electric power is then collected by a capacitor through an alternating current (AC)/direct current (DC) converter circuit (diode bridge circuit). To describe the power-harvesting process, a numerical model is developed to calculate the output voltage from the piezoelectric patch, the charge on the capacitor and the power-harvesting efficiency of the piezoelectric coupled vibrating beam. In addition, an experimental study is conducted to measure the generated voltage on the piezoelectric patch to verify the proposed numerical model. The effects of the excitation angular frequency and the patch size and location on the power-harvesting efficiency are discussed for the optimal design. The research provides a guideline for optimal designs of power-harvesting devices made of piezoelectric beam structures. © 2012 IOP Publishing Ltd.