Synchronized switch piezoelectric energy harvesting using rotating magnetic ball and reed switches

Abstract

Synchronized switch harvesting on inductor (SSHI) interface circuit has been developed to boost the harvesting capability of piezoelectric energy harvesters (PEHs). Although some electronic self-powered peak-detector and switching circuits have been proposed to support the practical realization of SSHI, the energy dissipation and voltage drops in transistors and diodes of the self-powered circuits might significantly deteriorate the actual energy harvesting performance. Some mechatronic designs were proposed as well. However, most of their switches are activated by touch impacts, which might introduce undesired high-order vibrations to the main structure. In this paper, rather than using the impact-engaged strategy discussed in the literature, a new mechanism using a magnetic ball for vibration synchronization and reed switches for switching operation is proposed. A PEH shunted to an SSHI interface circuit using the proposed mechatronic approach has been prototyped. Since the peak-detection and switching operations are completed by a mechanical mechanism, less passive electrical components, which consume extra energy, are required in our proposed design. Therefore, the overall energy harvesting performance is improved. Numerical simulations and experimental tests have validated the feasibility of the proposed design. The experimental results have shown that the power output produced by the proposed mechatronic self-powered SSHI design can be increased by and , as compared with the cases using a benchmark standard energy harvesting bridge rectifier and an electronic self-powered SSHI solutions, respectively. Moreover, owing to the new mechatronic design, the auxiliary mechanical components are embedded in the tip block of the cantilevered PEH, rendering the whole system to be a compact design.