Piezoelectric Energy Harvester including a Monitoring Circuit for Detecting Harvester Alteration or Downgrading

摘要

The energy harvesting module is provided with a pendular unit comprising an inertial mass coupled to an elastic piezoelectric beam providing a power voltage. An acceleration sensor provides a signal representative of the instantaneous acceleration of the beam in a direction perpendicular to a surface of the beam, and an angular speed sensor provides a signal representative of the instantaneous angular speed of rotation of the beam about an axis perpendicular to a plane of bending of the beam. Based on the voltage, acceleration and angular speed values, a beam integrity monitoring circuit estimates parameters of a mechanical-electrical transfer function and derives therefrom metrics representative of physical and electrical parameters of the pendular unit and of the material of the beam. This makes it possible to evaluate the proper operation of the energy harvester and to detect a potential performance decrease liable to lead to a failure in the more or less short term.