System design of a time-controlled broadband piezoelectric energy harvesting interface circuit

This paper presents a novel system design of an adaptive time-controlled energy harvesting interface circuit for broadening the bandwidth of piezoelectric transducers. The proposed system monitors the excitation frequency and delays the switching activity accordingly to achieve optimal impedance matching. The system and the theory for calculating the time delay values are described in detail. Simulation result shows that the proposed system is able to generate nearly as much power as the theoretical limitation over a large range of excitation frequency, and the bandwidth increases from 3.7 Hz to more than 70 Hz.