An Integrated High-Performance Active Rectifier for Piezoelectric Vibration Energy Harvesting Systems

Abstract

In this letter, a highly efficient active full-bridge rectifier is proposed for piezoelectric (PE) vibration energy harvesting systems. By replacing the passive diodes with an operational amplifier-controlled active counterpart and adding a switch in parallel with the transducer, the proposed rectifier solves the dc-offset problem of the comparator-based active diode, minimizes the voltage drop along the conduction path, and extracts more power from the transducer, all of which lead to better power extraction and conversion capability. The proposed rectifier, implemented in 0.18-μm CMOS technology, shows 90% power conversion efficiency and 81 μW output power, with values corresponding to 1.5 times and 3.4 times the values for a conventional full-bridge rectifier.Index Terms-Active rectifier, CMOS, full-bridge rectifier, operational amplifier, piezoelectric (PE), transducer, vibration energy harvesting.

A Piezoelectric Energy Harvester with High Efficiency and Low Circuit Complexity

“…al proposed a rectifier which implements diodes with two cross-coupled PMOS transistors and comparator-based NMOS transistors [5], and the rectifier called Lam rectifier in this paper is highly efficient. The proposed rectifier incorporates synchronized switching to Lam rectifier to realize an SS rectifier, which will further improve the efficiency.…”

“…Conventional full bridge rectifiers with passive diodes suffer from low efficiency due to (i) large power dissipation across the passive diodes and (ii) inability to extract large power from the capacitive PE source. Various configurations of active diodes were investigated to reduce power dissipation of passive diodes, and a rectifier based on cross-coupled PMOS transistor and comparators in [5] achieves high efficiency. To extract maximum power from the capacitive source of a PE transducer, two nonlinear approaches were investigated [1][2][3][4][5].…”

“…Various configurations of active diodes were investigated to reduce power dissipation of passive diodes, and a rectifier based on cross-coupled PMOS transistor and comparators in [5] achieves high efficiency. To extract maximum power from the capacitive source of a PE transducer, two nonlinear approaches were investigated [1][2][3][4][5]. The first approach is to discharge the capacitor with a switch when the PE transducer current changes its direction from positive to negative or vice versa [1,2,4,10].…”

“…The control circuitry for the SS rectifier and the buck converter is much simpler compared with other existing PE energy harvesters, which results in high efficiency. The proposed SS rectifier adds two switches to the rectifier reported in [5] for synchronized switching, but unlike existing SS rectifiers it does not require external supply voltages.…”

An Active Voltage Doubling Rectifier with Unbalanced-Biased Comparators for Piezoelectric Energy Harvesters

“…The rectifier achieves a PCE equal to 80.5% while operating with an input frequency of 13.56 MHz and an amplitude of 3.8V. Based on the same CCAF structure, Sun Y et al [12] apply an operational amplifier-controlled active diode and a switch in parallel with a transducer to improve the PCE by solving the dc-offset issue of the comparator-controlled active diode. This rectifier shows a PCE of 90% when operated with a 200 Hz sinusoidal voltage having an amplitude equal to 1.5 V and a resistive load of 95 kΩ.…”