An Efficient SSHI Interface With Increased Input Range for Piezoelectric Energy Harvesting Under Variable Conditions

Abstract

Abstract-Piezoelectric vibration energy harvesters have been widely researched and are increasingly employed for powering wireless sensor nodes. The Synchronized Switch Harvesting on Inductor (SSHI) circuit is one of the most efficient interfaces for piezoelectric vibration energy harvesters. However, the traditional incarnation of this circuit suffers from a significant startup issue that limits operation in low and variable amplitude vibration environments. This paper addresses this start-up issue for the SSHI rectifier by proposing a new architecture with SSHI startup circuitry. The startup circuitry monitors if the SSHI circuit is operating correctly and re-starts the SSHI interface if required. The proposed circuit is comprehensively analyzed and experimentally validated through tests conducted by integrating a commercial piezoelectric vibration energy harvester with the new interface circuit designed in a 0.35 µm HV CMOS process. Compared to conventional SSHI rectifiers, the proposed circuit significantly decreases the required minimum input excitation amplitude before energy can be harvested, making it possible to extract energy over an increased excitation range.Index Terms-Energy harvesting, piezoelectric transducer, synchronized switch harvesting on inductor (SSHI), rectifier.

An Adaptable Interface Circuit With Multistage Energy Extraction for Low-Power Piezoelectric Energy Harvesting MEMS

“…Beside standard rectification, switching approaches based on nonlinear processing of the voltage across PEH are used to enhance the extracted power, including synchronized switching [13], [14], single supply prebiasing [15], and synchronous electric charge extraction (SECE) [16], [17] techniques. Synchronized switch harvesting on inductor (SSHI) [18], [19] benefits from charge inversion on C p through recycling inductor. In this way, opposite charge generation is initiated close to conduction threshold of the rectifier.…”

Tuning Techniques for Piezoelectric and Electromagnetic Vibration Energy Harvesters

“…Therefore, a second objective to fulfill is the matching of the RVEH with its optimal load impedance, frequency by frequency. This is the aim of the so-called electrical tuning techniques (ETTs) [96][97][98][99][100][101][102]. It is worth noting that the application of the ETTs of course does not change the mechanical resonance frequency of a RVEH.…”

Asymmetric SECE Piezoelectric Energy Harvester Under Weak Excitation

“…These sensors indicate that an operating voltage of less than 2 V is widely used for lowpower applications [14][15][16][17][18][19][20][21]. Inductor-based PEHs such as SSHI, SECE, and precharging SECE in [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] are widely used for IoT devices. Recently, the sense-and-sat (SaS) scheme in [38] enhances the harvested power by maintaining the input near the maximum-power point at the expense of multiple switching in a cycle.…”