A unified approach to optimal conditions of power harvesting using electromagnetic and piezoelectric transducers

Power harvesting systems generate electric power from mechanical vibration using electromechanical transducers. To assess the practical performance of these systems, it is important to be able to estimate the maximum power that could be harvested from a specific structure and to derive the optimal conditions for the harvesting. We introduce a two-port network model which can fully describe the electromechanical coupled dynamics of the transducer, including the interaction between the structure and the electrical load in a unified manner. Electromagnetic and piezoelectric transducers are then considered as special cases of this general treatment. The power harvested by both types of transducer on a simply supported beam is derived and the optimal matching conditions and the maximum harvested power are obtained theoretically. In this numerical example, a piezoelectric transducer would have higher potential than an electromagnetic device of equal mass for the harvesting, but only when the transducer parameters are tuned optimally.