Design of Synchronous Charge Extraction Multi-input Piezoelectric Energy Harvesting Circuit

Piezoelectric energy harvesting (PEH) holds remarkable potential in energizing low-power sensors within wireless sensor networks, thereby alleviating the necessity for frequent battery replacements. Nevertheless, the output power yielded by a solitary piezoelectric element often proves inadequate to meet the demands of powering sensor nodes. Multi-input piezoelectric energy harvesters emerges as a compelling strategy to not only bolster power output but also to expand operational bandwidth. This augmentation necessitates judicious considerations in the design of energy harvesting circuits, with due regard for the distinct attributes inherent to various harvesters. A multi-input self-powered parallel synchronized switch harvesting on inductor (MISP-SSHI) circuit for piezoelectric energy harvesting is proposed in this study. The MISP-SSHI circuit adeptly addresses the divergence in voltage amplitudes and phase disparities across piezoelectric elements, while effectively obviating the mutual interference that can arise during energy extraction. A peak detection module is introduced and meticulously engineered to discern the peak of the piezoelectric output signal, which facilitates energy extraction without necessitating any external power supply. This process entails the judicious extraction of charge from both the clamped capacitance and the peak detection capacitance of the piezoelectric element, culminating in a discernible enhancement of the energy conversion efficiency. The intricate interplay between output power, efficiency, and load resistance characterizing the MISP-SSHI is rigorously examined through a combination of simulation and experimental analyses. A comparative simulation evaluation is conducted under varying excitation conditions. Substantiation of the theoretical framework is further attained through the integration of a DC-DC converter and the meticulous implementation of impedance matching across diverse load scenarios. Encouragingly, the alignment between simulation results and experimental outcomes lends credence to the efficacy of the proposed circuit design.