Design of a controller to improve the performance of a piezoelectric energy harvester under wind-induced galloping effect

Abstract

In the field of energy harvesting, several models have been developed aiming to the conversion from wind energy into electrical, approaching distincts flow phenomena and harvesting mechanisms. In this context, this research project aims to implement a control system applied to a piezoelectric energy harvester subjected to vibration induced by wind flow. The purpose of the control system is to keep, whenever is possible, the device under the aeroelastic effect of galloping, amplifying the vibration amplitude, and improving the process of energy conversion. The device consists of a cantilever beam containing a prismatic body (bluff body) rigidly coupled at its free end. This body contains external adjustable expansion rods with displacement controlled by a servo motor, making it possible to change the geometry of its face and, therefore, the area in contact with the wind. The device also has a piezoelectric device, which is rigidly coupled to the beam and used both as a vibration sensor and as a energy conversion mechanism (connected to a load resistor). For determination of the dynamic behavior of the energy conversion device, it will be experimented in a wind tunnel, in which variations in wind speed and contact area will be imposed. With this, it is possible to design the control system taking into account the performance specifications to be established. Once the control system has been designed, it will be implemented using a micro-controlled board and new wind tunnel tests will be carried out in order to validate the proposed control system. It is expected that an efficient active control system can be designed in order to maintain the system under specific vibrating conditions, thus having a satisfactory performance in the regarding energy conversion.