Non-Linear Switching Circuit for Active Voltage Rectification and Ripples Reduction of Piezoelectric Energy Harvesters

Abstract

This paper describes an improved non-linear switching circuit (INLSC) for active rectification of voltage and reduction of ripples in the voltage waveform for the piezoelectric energy harvesting (PEH) system. The proposed converter controls the alternating current (AC) generated by the piezoelectric device (PD) under mechanical vibration. The proposed circuit combines the boost and buck-boost processes through a switching process, which functions in both positive and negative cycles. In addition, it controls the voltage and frequency of the load capacitor. In this process, the passive components in the circuit are energised by being short with the AC voltage using switching signals, which facilitates the active rectification of ultra-low AC voltage. Design considerations, theoretical analysis, simulations and experimental results are presented. It was shown that the circuit was able to control the switching signal and to convert low AC voltage (0.44 Vi) to high direct current (DC) voltage (6.5 Vdc) while achieving an output power of 469 µW which outperforms the existing similar circuits and synchronous rectifier circuit. The ripples in the rectified voltage were also comparatively less. Application-wise, the proposed circuit could power a manually connected 7-segments display, commonly used for traffic applications.

Analysis of the Methods for Realization of Low-Power Piezoelectric Energy Harvesting Circuits for Wearable Battery-Free Power Supply Devices

“…In the last 2 years, various practical realizations of piezoelectric power conversion devices have been published [85,94,[99][100][101][102][103]. In this section, seven devices for piezoelectric energy harvesting are presented and compared.…”

“…The other two switches (M 1 and M 2 ) are controlled by the external circuits. The eight possible modes of operation are described in detail in [99]. The presented topology uses a classical H-bridge with enchanted logic control which optimizes the power extraction from the piezo generator.…”

A Self-Powered VDJT AC–DC Conversion Circuit for Piezoelectric Energy Harvesting Systems

“…The generated current by the PG as a result of its mechanical stimulation may be represented as [6,11,34,37]:…”

“…where I ac and ω are the magnitude of current and angular frequency, respectively (while t is the time). The generated current by the PG as a result of its mechanical stimulation may be represented as [6,11,34,37]:…”

“…In practice, PGs are confined to low-power domains in the micro/milliwatt category caused by physically constrained features like internal capacitance and resistance [1][2][3][4]. They can withstand extremely high pressure but have minimal strain and make huge material quantities challenging to use [5][6][7][8][9]. In contrast, most anticipated excitations are generally in the range of 0.1 to 1 kHz and produce low voltage levels, whereas most electronic equipment requires 3 to 5 V dc.…”